linux/drivers/ide/ide-tape.c
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   1/*
   2 * linux/drivers/ide/ide-tape.c         Version 1.19    Nov, 2003
   3 *
   4 * Copyright (C) 1995 - 1999 Gadi Oxman <gadio@netvision.net.il>
   5 *
   6 * $Header$
   7 *
   8 * This driver was constructed as a student project in the software laboratory
   9 * of the faculty of electrical engineering in the Technion - Israel's
  10 * Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
  11 *
  12 * It is hereby placed under the terms of the GNU general public license.
  13 * (See linux/COPYING).
  14 */
  15 
  16/*
  17 * IDE ATAPI streaming tape driver.
  18 *
  19 * This driver is a part of the Linux ide driver and works in co-operation
  20 * with linux/drivers/block/ide.c.
  21 *
  22 * The driver, in co-operation with ide.c, basically traverses the 
  23 * request-list for the block device interface. The character device
  24 * interface, on the other hand, creates new requests, adds them
  25 * to the request-list of the block device, and waits for their completion.
  26 *
  27 * Pipelined operation mode is now supported on both reads and writes.
  28 *
  29 * The block device major and minor numbers are determined from the
  30 * tape's relative position in the ide interfaces, as explained in ide.c.
  31 *
  32 * The character device interface consists of the following devices:
  33 *
  34 * ht0          major 37, minor 0       first  IDE tape, rewind on close.
  35 * ht1          major 37, minor 1       second IDE tape, rewind on close.
  36 * ...
  37 * nht0         major 37, minor 128     first  IDE tape, no rewind on close.
  38 * nht1         major 37, minor 129     second IDE tape, no rewind on close.
  39 * ...
  40 *
  41 * Run linux/scripts/MAKEDEV.ide to create the above entries.
  42 *
  43 * The general magnetic tape commands compatible interface, as defined by
  44 * include/linux/mtio.h, is accessible through the character device.
  45 *
  46 * General ide driver configuration options, such as the interrupt-unmask
  47 * flag, can be configured by issuing an ioctl to the block device interface,
  48 * as any other ide device.
  49 *
  50 * Our own ide-tape ioctl's can be issued to either the block device or
  51 * the character device interface.
  52 *
  53 * Maximal throughput with minimal bus load will usually be achieved in the
  54 * following scenario:
  55 *
  56 *      1.      ide-tape is operating in the pipelined operation mode.
  57 *      2.      No buffering is performed by the user backup program.
  58 *
  59 * Testing was done with a 2 GB CONNER CTMA 4000 IDE ATAPI Streaming Tape Drive.
  60 * 
  61 * Ver 0.1   Nov  1 95   Pre-working code :-)
  62 * Ver 0.2   Nov 23 95   A short backup (few megabytes) and restore procedure
  63 *                        was successful ! (Using tar cvf ... on the block
  64 *                        device interface).
  65 *                       A longer backup resulted in major swapping, bad
  66 *                        overall Linux performance and eventually failed as
  67 *                        we received non serial read-ahead requests from the
  68 *                        buffer cache.
  69 * Ver 0.3   Nov 28 95   Long backups are now possible, thanks to the
  70 *                        character device interface. Linux's responsiveness
  71 *                        and performance doesn't seem to be much affected
  72 *                        from the background backup procedure.
  73 *                       Some general mtio.h magnetic tape operations are
  74 *                        now supported by our character device. As a result,
  75 *                        popular tape utilities are starting to work with
  76 *                        ide tapes :-)
  77 *                       The following configurations were tested:
  78 *                              1. An IDE ATAPI TAPE shares the same interface
  79 *                                 and irq with an IDE ATAPI CDROM.
  80 *                              2. An IDE ATAPI TAPE shares the same interface
  81 *                                 and irq with a normal IDE disk.
  82 *                        Both configurations seemed to work just fine !
  83 *                        However, to be on the safe side, it is meanwhile
  84 *                        recommended to give the IDE TAPE its own interface
  85 *                        and irq.
  86 *                       The one thing which needs to be done here is to
  87 *                        add a "request postpone" feature to ide.c,
  88 *                        so that we won't have to wait for the tape to finish
  89 *                        performing a long media access (DSC) request (such
  90 *                        as a rewind) before we can access the other device
  91 *                        on the same interface. This effect doesn't disturb
  92 *                        normal operation most of the time because read/write
  93 *                        requests are relatively fast, and once we are
  94 *                        performing one tape r/w request, a lot of requests
  95 *                        from the other device can be queued and ide.c will
  96 *                        service all of them after this single tape request.
  97 * Ver 1.0   Dec 11 95   Integrated into Linux 1.3.46 development tree.
  98 *                       On each read / write request, we now ask the drive
  99 *                        if we can transfer a constant number of bytes
 100 *                        (a parameter of the drive) only to its buffers,
 101 *                        without causing actual media access. If we can't,
 102 *                        we just wait until we can by polling the DSC bit.
 103 *                        This ensures that while we are not transferring
 104 *                        more bytes than the constant referred to above, the
 105 *                        interrupt latency will not become too high and
 106 *                        we won't cause an interrupt timeout, as happened
 107 *                        occasionally in the previous version.
 108 *                       While polling for DSC, the current request is
 109 *                        postponed and ide.c is free to handle requests from
 110 *                        the other device. This is handled transparently to
 111 *                        ide.c. The hwgroup locking method which was used
 112 *                        in the previous version was removed.
 113 *                       Use of new general features which are provided by
 114 *                        ide.c for use with atapi devices.
 115 *                        (Programming done by Mark Lord)
 116 *                       Few potential bug fixes (Again, suggested by Mark)
 117 *                       Single character device data transfers are now
 118 *                        not limited in size, as they were before.
 119 *                       We are asking the tape about its recommended
 120 *                        transfer unit and send a larger data transfer
 121 *                        as several transfers of the above size.
 122 *                        For best results, use an integral number of this
 123 *                        basic unit (which is shown during driver
 124 *                        initialization). I will soon add an ioctl to get
 125 *                        this important parameter.
 126 *                       Our data transfer buffer is allocated on startup,
 127 *                        rather than before each data transfer. This should
 128 *                        ensure that we will indeed have a data buffer.
 129 * Ver 1.1   Dec 14 95   Fixed random problems which occurred when the tape
 130 *                        shared an interface with another device.
 131 *                        (poll_for_dsc was a complete mess).
 132 *                       Removed some old (non-active) code which had
 133 *                        to do with supporting buffer cache originated
 134 *                        requests.
 135 *                       The block device interface can now be opened, so
 136 *                        that general ide driver features like the unmask
 137 *                        interrupts flag can be selected with an ioctl.
 138 *                        This is the only use of the block device interface.
 139 *                       New fast pipelined operation mode (currently only on
 140 *                        writes). When using the pipelined mode, the
 141 *                        throughput can potentially reach the maximum
 142 *                        tape supported throughput, regardless of the
 143 *                        user backup program. On my tape drive, it sometimes
 144 *                        boosted performance by a factor of 2. Pipelined
 145 *                        mode is enabled by default, but since it has a few
 146 *                        downfalls as well, you may want to disable it.
 147 *                        A short explanation of the pipelined operation mode
 148 *                        is available below.
 149 * Ver 1.2   Jan  1 96   Eliminated pipelined mode race condition.
 150 *                       Added pipeline read mode. As a result, restores
 151 *                        are now as fast as backups.
 152 *                       Optimized shared interface behavior. The new behavior
 153 *                        typically results in better IDE bus efficiency and
 154 *                        higher tape throughput.
 155 *                       Pre-calculation of the expected read/write request
 156 *                        service time, based on the tape's parameters. In
 157 *                        the pipelined operation mode, this allows us to
 158 *                        adjust our polling frequency to a much lower value,
 159 *                        and thus to dramatically reduce our load on Linux,
 160 *                        without any decrease in performance.
 161 *                       Implemented additional mtio.h operations.
 162 *                       The recommended user block size is returned by
 163 *                        the MTIOCGET ioctl.
 164 *                       Additional minor changes.
 165 * Ver 1.3   Feb  9 96   Fixed pipelined read mode bug which prevented the
 166 *                        use of some block sizes during a restore procedure.
 167 *                       The character device interface will now present a
 168 *                        continuous view of the media - any mix of block sizes
 169 *                        during a backup/restore procedure is supported. The
 170 *                        driver will buffer the requests internally and
 171 *                        convert them to the tape's recommended transfer
 172 *                        unit, making performance almost independent of the
 173 *                        chosen user block size.
 174 *                       Some improvements in error recovery.
 175 *                       By cooperating with ide-dma.c, bus mastering DMA can
 176 *                        now sometimes be used with IDE tape drives as well.
 177 *                        Bus mastering DMA has the potential to dramatically
 178 *                        reduce the CPU's overhead when accessing the device,
 179 *                        and can be enabled by using hdparm -d1 on the tape's
 180 *                        block device interface. For more info, read the
 181 *                        comments in ide-dma.c.
 182 * Ver 1.4   Mar 13 96   Fixed serialize support.
 183 * Ver 1.5   Apr 12 96   Fixed shared interface operation, broken in 1.3.85.
 184 *                       Fixed pipelined read mode inefficiency.
 185 *                       Fixed nasty null dereferencing bug.
 186 * Ver 1.6   Aug 16 96   Fixed FPU usage in the driver.
 187 *                       Fixed end of media bug.
 188 * Ver 1.7   Sep 10 96   Minor changes for the CONNER CTT8000-A model.
 189 * Ver 1.8   Sep 26 96   Attempt to find a better balance between good
 190 *                        interactive response and high system throughput.
 191 * Ver 1.9   Nov  5 96   Automatically cross encountered filemarks rather
 192 *                        than requiring an explicit FSF command.
 193 *                       Abort pending requests at end of media.
 194 *                       MTTELL was sometimes returning incorrect results.
 195 *                       Return the real block size in the MTIOCGET ioctl.
 196 *                       Some error recovery bug fixes.
 197 * Ver 1.10  Nov  5 96   Major reorganization.
 198 *                       Reduced CPU overhead a bit by eliminating internal
 199 *                        bounce buffers.
 200 *                       Added module support.
 201 *                       Added multiple tape drives support.
 202 *                       Added partition support.
 203 *                       Rewrote DSC handling.
 204 *                       Some portability fixes.
 205 *                       Removed ide-tape.h.
 206 *                       Additional minor changes.
 207 * Ver 1.11  Dec  2 96   Bug fix in previous DSC timeout handling.
 208 *                       Use ide_stall_queue() for DSC overlap.
 209 *                       Use the maximum speed rather than the current speed
 210 *                        to compute the request service time.
 211 * Ver 1.12  Dec  7 97   Fix random memory overwriting and/or last block data
 212 *                        corruption, which could occur if the total number
 213 *                        of bytes written to the tape was not an integral
 214 *                        number of tape blocks.
 215 *                       Add support for INTERRUPT DRQ devices.
 216 * Ver 1.13  Jan  2 98   Add "speed == 0" work-around for HP COLORADO 5GB
 217 * Ver 1.14  Dec 30 98   Partial fixes for the Sony/AIWA tape drives.
 218 *                       Replace cli()/sti() with hwgroup spinlocks.
 219 * Ver 1.15  Mar 25 99   Fix SMP race condition by replacing hwgroup
 220 *                        spinlock with private per-tape spinlock.
 221 * Ver 1.16  Sep  1 99   Add OnStream tape support.
 222 *                       Abort read pipeline on EOD.
 223 *                       Wait for the tape to become ready in case it returns
 224 *                        "in the process of becoming ready" on open().
 225 *                       Fix zero padding of the last written block in
 226 *                        case the tape block size is larger than PAGE_SIZE.
 227 *                       Decrease the default disconnection time to tn.
 228 * Ver 1.16e Oct  3 99   Minor fixes.
 229 * Ver 1.16e1 Oct 13 99  Patches by Arnold Niessen,
 230 *                          niessen@iae.nl / arnold.niessen@philips.com
 231 *                   GO-1)  Undefined code in idetape_read_position
 232 *                              according to Gadi's email
 233 *                   AJN-1) Minor fix asc == 11 should be asc == 0x11
 234 *                               in idetape_issue_packet_command (did effect
 235 *                               debugging output only)
 236 *                   AJN-2) Added more debugging output, and
 237 *                              added ide-tape: where missing. I would also
 238 *                              like to add tape->name where possible
 239 *                   AJN-3) Added different debug_level's 
 240 *                              via /proc/ide/hdc/settings
 241 *                              "debug_level" determines amount of debugging output;
 242 *                              can be changed using /proc/ide/hdx/settings
 243 *                              0 : almost no debugging output
 244 *                              1 : 0+output errors only
 245 *                              2 : 1+output all sensekey/asc
 246 *                              3 : 2+follow all chrdev related procedures
 247 *                              4 : 3+follow all procedures
 248 *                              5 : 4+include pc_stack rq_stack info
 249 *                              6 : 5+USE_COUNT updates
 250 *                   AJN-4) Fixed timeout for retension in idetape_queue_pc_tail
 251 *                              from 5 to 10 minutes
 252 *                   AJN-5) Changed maximum number of blocks to skip when
 253 *                              reading tapes with multiple consecutive write
 254 *                              errors from 100 to 1000 in idetape_get_logical_blk
 255 *                   Proposed changes to code:
 256 *                   1) output "logical_blk_num" via /proc
 257 *                   2) output "current_operation" via /proc
 258 *                   3) Either solve or document the fact that `mt rewind' is
 259 *                      required after reading from /dev/nhtx to be
 260 *                      able to rmmod the idetape module;
 261 *                      Also, sometimes an application finishes but the
 262 *                      device remains `busy' for some time. Same cause ?
 263 *                   Proposed changes to release-notes:
 264 *                   4) write a simple `quickstart' section in the
 265 *                      release notes; I volunteer if you don't want to
 266 *                   5) include a pointer to video4linux in the doc
 267 *                      to stimulate video applications
 268 *                   6) release notes lines 331 and 362: explain what happens
 269 *                      if the application data rate is higher than 1100 KB/s; 
 270 *                      similar approach to lower-than-500 kB/s ?
 271 *                   7) 6.6 Comparison; wouldn't it be better to allow different 
 272 *                      strategies for read and write ?
 273 *                      Wouldn't it be better to control the tape buffer
 274 *                      contents instead of the bandwidth ?
 275 *                   8) line 536: replace will by would (if I understand
 276 *                      this section correctly, a hypothetical and unwanted situation
 277 *                       is being described)
 278 * Ver 1.16f Dec 15 99   Change place of the secondary OnStream header frames.
 279 * Ver 1.17  Nov 2000 / Jan 2001  Marcel Mol, marcel@mesa.nl
 280 *                      - Add idetape_onstream_mode_sense_tape_parameter_page
 281 *                        function to get tape capacity in frames: tape->capacity.
 282 *                      - Add support for DI-50 drives( or any DI- drive).
 283 *                      - 'workaround' for read error/blank block around block 3000.
 284 *                      - Implement Early warning for end of media for Onstream.
 285 *                      - Cosmetic code changes for readability.
 286 *                      - Idetape_position_tape should not use SKIP bit during
 287 *                        Onstream read recovery.
 288 *                      - Add capacity, logical_blk_num and first/last_frame_position
 289 *                        to /proc/ide/hd?/settings.
 290 *                      - Module use count was gone in the Linux 2.4 driver.
 291 * Ver 1.17a Apr 2001 Willem Riede osst@riede.org
 292 *                      - Get drive's actual block size from mode sense block descriptor
 293 *                      - Limit size of pipeline
 294 * Ver 1.17b Oct 2002   Alan Stern <stern@rowland.harvard.edu>
 295 *                      Changed IDETAPE_MIN_PIPELINE_STAGES to 1 and actually used
 296 *                       it in the code!
 297 *                      Actually removed aborted stages in idetape_abort_pipeline
 298 *                       instead of just changing the command code.
 299 *                      Made the transfer byte count for Request Sense equal to the
 300 *                       actual length of the data transfer.
 301 *                      Changed handling of partial data transfers: they do not
 302 *                       cause DMA errors.
 303 *                      Moved initiation of DMA transfers to the correct place.
 304 *                      Removed reference to unallocated memory.
 305 *                      Made __idetape_discard_read_pipeline return the number of
 306 *                       sectors skipped, not the number of stages.
 307 *                      Replaced errant kfree() calls with __idetape_kfree_stage().
 308 *                      Fixed off-by-one error in testing the pipeline length.
 309 *                      Fixed handling of filemarks in the read pipeline.
 310 *                      Small code optimization for MTBSF and MTBSFM ioctls.
 311 *                      Don't try to unlock the door during device close if is
 312 *                       already unlocked!
 313 *                      Cosmetic fixes to miscellaneous debugging output messages.
 314 *                      Set the minimum /proc/ide/hd?/settings values for "pipeline",
 315 *                       "pipeline_min", and "pipeline_max" to 1.
 316 *
 317 * Here are some words from the first releases of hd.c, which are quoted
 318 * in ide.c and apply here as well:
 319 *
 320 * | Special care is recommended.  Have Fun!
 321 *
 322 */
 323
 324/*
 325 * An overview of the pipelined operation mode.
 326 *
 327 * In the pipelined write mode, we will usually just add requests to our
 328 * pipeline and return immediately, before we even start to service them. The
 329 * user program will then have enough time to prepare the next request while
 330 * we are still busy servicing previous requests. In the pipelined read mode,
 331 * the situation is similar - we add read-ahead requests into the pipeline,
 332 * before the user even requested them.
 333 *
 334 * The pipeline can be viewed as a "safety net" which will be activated when
 335 * the system load is high and prevents the user backup program from keeping up
 336 * with the current tape speed. At this point, the pipeline will get
 337 * shorter and shorter but the tape will still be streaming at the same speed.
 338 * Assuming we have enough pipeline stages, the system load will hopefully
 339 * decrease before the pipeline is completely empty, and the backup program
 340 * will be able to "catch up" and refill the pipeline again.
 341 * 
 342 * When using the pipelined mode, it would be best to disable any type of
 343 * buffering done by the user program, as ide-tape already provides all the
 344 * benefits in the kernel, where it can be done in a more efficient way.
 345 * As we will usually not block the user program on a request, the most
 346 * efficient user code will then be a simple read-write-read-... cycle.
 347 * Any additional logic will usually just slow down the backup process.
 348 *
 349 * Using the pipelined mode, I get a constant over 400 KBps throughput,
 350 * which seems to be the maximum throughput supported by my tape.
 351 *
 352 * However, there are some downfalls:
 353 *
 354 *      1.      We use memory (for data buffers) in proportional to the number
 355 *              of pipeline stages (each stage is about 26 KB with my tape).
 356 *      2.      In the pipelined write mode, we cheat and postpone error codes
 357 *              to the user task. In read mode, the actual tape position
 358 *              will be a bit further than the last requested block.
 359 *
 360 * Concerning (1):
 361 *
 362 *      1.      We allocate stages dynamically only when we need them. When
 363 *              we don't need them, we don't consume additional memory. In
 364 *              case we can't allocate stages, we just manage without them
 365 *              (at the expense of decreased throughput) so when Linux is
 366 *              tight in memory, we will not pose additional difficulties.
 367 *
 368 *      2.      The maximum number of stages (which is, in fact, the maximum
 369 *              amount of memory) which we allocate is limited by the compile
 370 *              time parameter IDETAPE_MAX_PIPELINE_STAGES.
 371 *
 372 *      3.      The maximum number of stages is a controlled parameter - We
 373 *              don't start from the user defined maximum number of stages
 374 *              but from the lower IDETAPE_MIN_PIPELINE_STAGES (again, we
 375 *              will not even allocate this amount of stages if the user
 376 *              program can't handle the speed). We then implement a feedback
 377 *              loop which checks if the pipeline is empty, and if it is, we
 378 *              increase the maximum number of stages as necessary until we
 379 *              reach the optimum value which just manages to keep the tape
 380 *              busy with minimum allocated memory or until we reach
 381 *              IDETAPE_MAX_PIPELINE_STAGES.
 382 *
 383 * Concerning (2):
 384 *
 385 *      In pipelined write mode, ide-tape can not return accurate error codes
 386 *      to the user program since we usually just add the request to the
 387 *      pipeline without waiting for it to be serviced. In case an error
 388 *      occurs, I will report it on the next user request.
 389 *
 390 *      In the pipelined read mode, subsequent read requests or forward
 391 *      filemark spacing will perform correctly, as we preserve all blocks
 392 *      and filemarks which we encountered during our excess read-ahead.
 393 * 
 394 *      For accurate tape positioning and error reporting, disabling
 395 *      pipelined mode might be the best option.
 396 *
 397 * You can enable/disable/tune the pipelined operation mode by adjusting
 398 * the compile time parameters below.
 399 */
 400
 401/*
 402 *      Possible improvements.
 403 *
 404 *      1.      Support for the ATAPI overlap protocol.
 405 *
 406 *              In order to maximize bus throughput, we currently use the DSC
 407 *              overlap method which enables ide.c to service requests from the
 408 *              other device while the tape is busy executing a command. The
 409 *              DSC overlap method involves polling the tape's status register
 410 *              for the DSC bit, and servicing the other device while the tape
 411 *              isn't ready.
 412 *
 413 *              In the current QIC development standard (December 1995),
 414 *              it is recommended that new tape drives will *in addition* 
 415 *              implement the ATAPI overlap protocol, which is used for the
 416 *              same purpose - efficient use of the IDE bus, but is interrupt
 417 *              driven and thus has much less CPU overhead.
 418 *
 419 *              ATAPI overlap is likely to be supported in most new ATAPI
 420 *              devices, including new ATAPI cdroms, and thus provides us
 421 *              a method by which we can achieve higher throughput when
 422 *              sharing a (fast) ATA-2 disk with any (slow) new ATAPI device.
 423 */
 424
 425#define IDETAPE_VERSION "1.19"
 426
 427#include <linux/module.h>
 428#include <linux/types.h>
 429#include <linux/string.h>
 430#include <linux/kernel.h>
 431#include <linux/delay.h>
 432#include <linux/timer.h>
 433#include <linux/mm.h>
 434#include <linux/interrupt.h>
 435#include <linux/jiffies.h>
 436#include <linux/major.h>
 437#include <linux/errno.h>
 438#include <linux/genhd.h>
 439#include <linux/slab.h>
 440#include <linux/pci.h>
 441#include <linux/ide.h>
 442#include <linux/smp_lock.h>
 443#include <linux/completion.h>
 444#include <linux/bitops.h>
 445#include <linux/mutex.h>
 446
 447#include <asm/byteorder.h>
 448#include <asm/irq.h>
 449#include <asm/uaccess.h>
 450#include <asm/io.h>
 451#include <asm/unaligned.h>
 452
 453/*
 454 * partition
 455 */
 456typedef struct os_partition_s {
 457        __u8    partition_num;
 458        __u8    par_desc_ver;
 459        __u16   wrt_pass_cntr;
 460        __u32   first_frame_addr;
 461        __u32   last_frame_addr;
 462        __u32   eod_frame_addr;
 463} os_partition_t;
 464
 465/*
 466 * DAT entry
 467 */
 468typedef struct os_dat_entry_s {
 469        __u32   blk_sz;
 470        __u16   blk_cnt;
 471        __u8    flags;
 472        __u8    reserved;
 473} os_dat_entry_t;
 474
 475/*
 476 * DAT
 477 */
 478#define OS_DAT_FLAGS_DATA       (0xc)
 479#define OS_DAT_FLAGS_MARK       (0x1)
 480
 481typedef struct os_dat_s {
 482        __u8            dat_sz;
 483        __u8            reserved1;
 484        __u8            entry_cnt;
 485        __u8            reserved3;
 486        os_dat_entry_t  dat_list[16];
 487} os_dat_t;
 488
 489#include <linux/mtio.h>
 490
 491/**************************** Tunable parameters *****************************/
 492
 493
 494/*
 495 *      Pipelined mode parameters.
 496 *
 497 *      We try to use the minimum number of stages which is enough to
 498 *      keep the tape constantly streaming. To accomplish that, we implement
 499 *      a feedback loop around the maximum number of stages:
 500 *
 501 *      We start from MIN maximum stages (we will not even use MIN stages
 502 *      if we don't need them), increment it by RATE*(MAX-MIN)
 503 *      whenever we sense that the pipeline is empty, until we reach
 504 *      the optimum value or until we reach MAX.
 505 *
 506 *      Setting the following parameter to 0 is illegal: the pipelined mode
 507 *      cannot be disabled (calculate_speeds() divides by tape->max_stages.)
 508 */
 509#define IDETAPE_MIN_PIPELINE_STAGES       1
 510#define IDETAPE_MAX_PIPELINE_STAGES     400
 511#define IDETAPE_INCREASE_STAGES_RATE     20
 512
 513/*
 514 *      The following are used to debug the driver:
 515 *
 516 *      Setting IDETAPE_DEBUG_INFO to 1 will report device capabilities.
 517 *      Setting IDETAPE_DEBUG_LOG to 1 will log driver flow control.
 518 *      Setting IDETAPE_DEBUG_BUGS to 1 will enable self-sanity checks in
 519 *      some places.
 520 *
 521 *      Setting them to 0 will restore normal operation mode:
 522 *
 523 *              1.      Disable logging normal successful operations.
 524 *              2.      Disable self-sanity checks.
 525 *              3.      Errors will still be logged, of course.
 526 *
 527 *      All the #if DEBUG code will be removed some day, when the driver
 528 *      is verified to be stable enough. This will make it much more
 529 *      esthetic.
 530 */
 531#define IDETAPE_DEBUG_INFO              0
 532#define IDETAPE_DEBUG_LOG               0
 533#define IDETAPE_DEBUG_BUGS              1
 534
 535/*
 536 *      After each failed packet command we issue a request sense command
 537 *      and retry the packet command IDETAPE_MAX_PC_RETRIES times.
 538 *
 539 *      Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
 540 */
 541#define IDETAPE_MAX_PC_RETRIES          3
 542
 543/*
 544 *      With each packet command, we allocate a buffer of
 545 *      IDETAPE_PC_BUFFER_SIZE bytes. This is used for several packet
 546 *      commands (Not for READ/WRITE commands).
 547 */
 548#define IDETAPE_PC_BUFFER_SIZE          256
 549
 550/*
 551 *      In various places in the driver, we need to allocate storage
 552 *      for packet commands and requests, which will remain valid while
 553 *      we leave the driver to wait for an interrupt or a timeout event.
 554 */
 555#define IDETAPE_PC_STACK                (10 + IDETAPE_MAX_PC_RETRIES)
 556
 557/*
 558 * Some drives (for example, Seagate STT3401A Travan) require a very long
 559 * timeout, because they don't return an interrupt or clear their busy bit
 560 * until after the command completes (even retension commands).
 561 */
 562#define IDETAPE_WAIT_CMD                (900*HZ)
 563
 564/*
 565 *      The following parameter is used to select the point in the internal
 566 *      tape fifo in which we will start to refill the buffer. Decreasing
 567 *      the following parameter will improve the system's latency and
 568 *      interactive response, while using a high value might improve system
 569 *      throughput.
 570 */
 571#define IDETAPE_FIFO_THRESHOLD          2
 572
 573/*
 574 *      DSC polling parameters.
 575 *
 576 *      Polling for DSC (a single bit in the status register) is a very
 577 *      important function in ide-tape. There are two cases in which we
 578 *      poll for DSC:
 579 *
 580 *      1.      Before a read/write packet command, to ensure that we
 581 *              can transfer data from/to the tape's data buffers, without
 582 *              causing an actual media access. In case the tape is not
 583 *              ready yet, we take out our request from the device
 584 *              request queue, so that ide.c will service requests from
 585 *              the other device on the same interface meanwhile.
 586 *
 587 *      2.      After the successful initialization of a "media access
 588 *              packet command", which is a command which can take a long
 589 *              time to complete (it can be several seconds or even an hour).
 590 *
 591 *              Again, we postpone our request in the middle to free the bus
 592 *              for the other device. The polling frequency here should be
 593 *              lower than the read/write frequency since those media access
 594 *              commands are slow. We start from a "fast" frequency -
 595 *              IDETAPE_DSC_MA_FAST (one second), and if we don't receive DSC
 596 *              after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
 597 *              lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
 598 *
 599 *      We also set a timeout for the timer, in case something goes wrong.
 600 *      The timeout should be longer then the maximum execution time of a
 601 *      tape operation.
 602 */
 603 
 604/*
 605 *      DSC timings.
 606 */
 607#define IDETAPE_DSC_RW_MIN              5*HZ/100        /* 50 msec */
 608#define IDETAPE_DSC_RW_MAX              40*HZ/100       /* 400 msec */
 609#define IDETAPE_DSC_RW_TIMEOUT          2*60*HZ         /* 2 minutes */
 610#define IDETAPE_DSC_MA_FAST             2*HZ            /* 2 seconds */
 611#define IDETAPE_DSC_MA_THRESHOLD        5*60*HZ         /* 5 minutes */
 612#define IDETAPE_DSC_MA_SLOW             30*HZ           /* 30 seconds */
 613#define IDETAPE_DSC_MA_TIMEOUT          2*60*60*HZ      /* 2 hours */
 614
 615/*************************** End of tunable parameters ***********************/
 616
 617/*
 618 *      Debugging/Performance analysis
 619 *
 620 *      I/O trace support
 621 */
 622#define USE_IOTRACE     0
 623#if USE_IOTRACE
 624#define IO_IDETAPE_FIFO 500
 625#endif
 626
 627/*
 628 *      Read/Write error simulation
 629 */
 630#define SIMULATE_ERRORS                 0
 631
 632/*
 633 *      For general magnetic tape device compatibility.
 634 */
 635typedef enum {
 636        idetape_direction_none,
 637        idetape_direction_read,
 638        idetape_direction_write
 639} idetape_chrdev_direction_t;
 640
 641struct idetape_bh {
 642        u32 b_size;
 643        atomic_t b_count;
 644        struct idetape_bh *b_reqnext;
 645        char *b_data;
 646};
 647
 648/*
 649 *      Our view of a packet command.
 650 */
 651typedef struct idetape_packet_command_s {
 652        u8 c[12];                               /* Actual packet bytes */
 653        int retries;                            /* On each retry, we increment retries */
 654        int error;                              /* Error code */
 655        int request_transfer;                   /* Bytes to transfer */
 656        int actually_transferred;               /* Bytes actually transferred */
 657        int buffer_size;                        /* Size of our data buffer */
 658        struct idetape_bh *bh;
 659        char *b_data;
 660        int b_count;
 661        u8 *buffer;                             /* Data buffer */
 662        u8 *current_position;                   /* Pointer into the above buffer */
 663        ide_startstop_t (*callback) (ide_drive_t *);    /* Called when this packet command is completed */
 664        u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];   /* Temporary buffer */
 665        unsigned long flags;                    /* Status/Action bit flags: long for set_bit */
 666} idetape_pc_t;
 667
 668/*
 669 *      Packet command flag bits.
 670 */
 671/* Set when an error is considered normal - We won't retry */
 672#define PC_ABORT                        0
 673/* 1 When polling for DSC on a media access command */
 674#define PC_WAIT_FOR_DSC                 1
 675/* 1 when we prefer to use DMA if possible */
 676#define PC_DMA_RECOMMENDED              2
 677/* 1 while DMA in progress */
 678#define PC_DMA_IN_PROGRESS              3
 679/* 1 when encountered problem during DMA */
 680#define PC_DMA_ERROR                    4
 681/* Data direction */
 682#define PC_WRITING                      5
 683
 684/*
 685 *      Capabilities and Mechanical Status Page
 686 */
 687typedef struct {
 688        unsigned        page_code       :6;     /* Page code - Should be 0x2a */
 689        __u8            reserved0_6     :1;
 690        __u8            ps              :1;     /* parameters saveable */
 691        __u8            page_length;            /* Page Length - Should be 0x12 */
 692        __u8            reserved2, reserved3;
 693        unsigned        ro              :1;     /* Read Only Mode */
 694        unsigned        reserved4_1234  :4;
 695        unsigned        sprev           :1;     /* Supports SPACE in the reverse direction */
 696        unsigned        reserved4_67    :2;
 697        unsigned        reserved5_012   :3;
 698        unsigned        efmt            :1;     /* Supports ERASE command initiated formatting */
 699        unsigned        reserved5_4     :1;
 700        unsigned        qfa             :1;     /* Supports the QFA two partition formats */
 701        unsigned        reserved5_67    :2;
 702        unsigned        lock            :1;     /* Supports locking the volume */
 703        unsigned        locked          :1;     /* The volume is locked */
 704        unsigned        prevent         :1;     /* The device defaults in the prevent state after power up */   
 705        unsigned        eject           :1;     /* The device can eject the volume */
 706        __u8            disconnect      :1;     /* The device can break request > ctl */        
 707        __u8            reserved6_5     :1;
 708        unsigned        ecc             :1;     /* Supports error correction */
 709        unsigned        cmprs           :1;     /* Supports data compression */
 710        unsigned        reserved7_0     :1;
 711        unsigned        blk512          :1;     /* Supports 512 bytes block size */
 712        unsigned        blk1024         :1;     /* Supports 1024 bytes block size */
 713        unsigned        reserved7_3_6   :4;
 714        unsigned        blk32768        :1;     /* slowb - the device restricts the byte count for PIO */
 715                                                /* transfers for slow buffer memory ??? */
 716                                                /* Also 32768 block size in some cases */
 717        __u16           max_speed;              /* Maximum speed supported in KBps */
 718        __u8            reserved10, reserved11;
 719        __u16           ctl;                    /* Continuous Transfer Limit in blocks */
 720        __u16           speed;                  /* Current Speed, in KBps */
 721        __u16           buffer_size;            /* Buffer Size, in 512 bytes */
 722        __u8            reserved18, reserved19;
 723} idetape_capabilities_page_t;
 724
 725/*
 726 *      Block Size Page
 727 */
 728typedef struct {
 729        unsigned        page_code       :6;     /* Page code - Should be 0x30 */
 730        unsigned        reserved1_6     :1;
 731        unsigned        ps              :1;
 732        __u8            page_length;            /* Page Length - Should be 2 */
 733        __u8            reserved2;
 734        unsigned        play32          :1;
 735        unsigned        play32_5        :1;
 736        unsigned        reserved2_23    :2;
 737        unsigned        record32        :1;
 738        unsigned        record32_5      :1;
 739        unsigned        reserved2_6     :1;
 740        unsigned        one             :1;
 741} idetape_block_size_page_t;
 742
 743/*
 744 *      A pipeline stage.
 745 */
 746typedef struct idetape_stage_s {
 747        struct request rq;                      /* The corresponding request */
 748        struct idetape_bh *bh;                  /* The data buffers */
 749        struct idetape_stage_s *next;           /* Pointer to the next stage */
 750} idetape_stage_t;
 751
 752/*
 753 *      REQUEST SENSE packet command result - Data Format.
 754 */
 755typedef struct {
 756        unsigned        error_code      :7;     /* Current of deferred errors */
 757        unsigned        valid           :1;     /* The information field conforms to QIC-157C */
 758        __u8            reserved1       :8;     /* Segment Number - Reserved */
 759        unsigned        sense_key       :4;     /* Sense Key */
 760        unsigned        reserved2_4     :1;     /* Reserved */
 761        unsigned        ili             :1;     /* Incorrect Length Indicator */
 762        unsigned        eom             :1;     /* End Of Medium */
 763        unsigned        filemark        :1;     /* Filemark */
 764        __u32           information __attribute__ ((packed));
 765        __u8            asl;                    /* Additional sense length (n-7) */
 766        __u32           command_specific;       /* Additional command specific information */
 767        __u8            asc;                    /* Additional Sense Code */
 768        __u8            ascq;                   /* Additional Sense Code Qualifier */
 769        __u8            replaceable_unit_code;  /* Field Replaceable Unit Code */
 770        unsigned        sk_specific1    :7;     /* Sense Key Specific */
 771        unsigned        sksv            :1;     /* Sense Key Specific information is valid */
 772        __u8            sk_specific2;           /* Sense Key Specific */
 773        __u8            sk_specific3;           /* Sense Key Specific */
 774        __u8            pad[2];                 /* Padding to 20 bytes */
 775} idetape_request_sense_result_t;
 776
 777
 778/*
 779 *      Most of our global data which we need to save even as we leave the
 780 *      driver due to an interrupt or a timer event is stored in a variable
 781 *      of type idetape_tape_t, defined below.
 782 */
 783typedef struct ide_tape_obj {
 784        ide_drive_t     *drive;
 785        ide_driver_t    *driver;
 786        struct gendisk  *disk;
 787        struct kref     kref;
 788
 789        /*
 790         *      Since a typical character device operation requires more
 791         *      than one packet command, we provide here enough memory
 792         *      for the maximum of interconnected packet commands.
 793         *      The packet commands are stored in the circular array pc_stack.
 794         *      pc_stack_index points to the last used entry, and warps around
 795         *      to the start when we get to the last array entry.
 796         *
 797         *      pc points to the current processed packet command.
 798         *
 799         *      failed_pc points to the last failed packet command, or contains
 800         *      NULL if we do not need to retry any packet command. This is
 801         *      required since an additional packet command is needed before the
 802         *      retry, to get detailed information on what went wrong.
 803         */
 804        /* Current packet command */
 805        idetape_pc_t *pc;
 806        /* Last failed packet command */
 807        idetape_pc_t *failed_pc;
 808        /* Packet command stack */
 809        idetape_pc_t pc_stack[IDETAPE_PC_STACK];
 810        /* Next free packet command storage space */
 811        int pc_stack_index;
 812        struct request rq_stack[IDETAPE_PC_STACK];
 813        /* We implement a circular array */
 814        int rq_stack_index;
 815
 816        /*
 817         *      DSC polling variables.
 818         *
 819         *      While polling for DSC we use postponed_rq to postpone the
 820         *      current request so that ide.c will be able to service
 821         *      pending requests on the other device. Note that at most
 822         *      we will have only one DSC (usually data transfer) request
 823         *      in the device request queue. Additional requests can be
 824         *      queued in our internal pipeline, but they will be visible
 825         *      to ide.c only one at a time.
 826         */
 827        struct request *postponed_rq;
 828        /* The time in which we started polling for DSC */
 829        unsigned long dsc_polling_start;
 830        /* Timer used to poll for dsc */
 831        struct timer_list dsc_timer;
 832        /* Read/Write dsc polling frequency */
 833        unsigned long best_dsc_rw_frequency;
 834        /* The current polling frequency */
 835        unsigned long dsc_polling_frequency;
 836        /* Maximum waiting time */
 837        unsigned long dsc_timeout;
 838
 839        /*
 840         *      Read position information
 841         */
 842        u8 partition;
 843        /* Current block */
 844        unsigned int first_frame_position;
 845        unsigned int last_frame_position;
 846        unsigned int blocks_in_buffer;
 847
 848        /*
 849         *      Last error information
 850         */
 851        u8 sense_key, asc, ascq;
 852
 853        /*
 854         *      Character device operation
 855         */
 856        unsigned int minor;
 857        /* device name */
 858        char name[4];
 859        /* Current character device data transfer direction */
 860        idetape_chrdev_direction_t chrdev_direction;
 861
 862        /*
 863         *      Device information
 864         */
 865        /* Usually 512 or 1024 bytes */
 866        unsigned short tape_block_size;
 867        int user_bs_factor;
 868        /* Copy of the tape's Capabilities and Mechanical Page */
 869        idetape_capabilities_page_t capabilities;
 870
 871        /*
 872         *      Active data transfer request parameters.
 873         *
 874         *      At most, there is only one ide-tape originated data transfer
 875         *      request in the device request queue. This allows ide.c to
 876         *      easily service requests from the other device when we
 877         *      postpone our active request. In the pipelined operation
 878         *      mode, we use our internal pipeline structure to hold
 879         *      more data requests.
 880         *
 881         *      The data buffer size is chosen based on the tape's
 882         *      recommendation.
 883         */
 884        /* Pointer to the request which is waiting in the device request queue */
 885        struct request *active_data_request;
 886        /* Data buffer size (chosen based on the tape's recommendation */
 887        int stage_size;
 888        idetape_stage_t *merge_stage;
 889        int merge_stage_size;
 890        struct idetape_bh *bh;
 891        char *b_data;
 892        int b_count;
 893        
 894        /*
 895         *      Pipeline parameters.
 896         *
 897         *      To accomplish non-pipelined mode, we simply set the following
 898         *      variables to zero (or NULL, where appropriate).
 899         */
 900        /* Number of currently used stages */
 901        int nr_stages;
 902        /* Number of pending stages */
 903        int nr_pending_stages;
 904        /* We will not allocate more than this number of stages */
 905        int max_stages, min_pipeline, max_pipeline;
 906        /* The first stage which will be removed from the pipeline */
 907        idetape_stage_t *first_stage;
 908        /* The currently active stage */
 909        idetape_stage_t *active_stage;
 910        /* Will be serviced after the currently active request */
 911        idetape_stage_t *next_stage;
 912        /* New requests will be added to the pipeline here */
 913        idetape_stage_t *last_stage;
 914        /* Optional free stage which we can use */
 915        idetape_stage_t *cache_stage;
 916        int pages_per_stage;
 917        /* Wasted space in each stage */
 918        int excess_bh_size;
 919
 920        /* Status/Action flags: long for set_bit */
 921        unsigned long flags;
 922        /* protects the ide-tape queue */
 923        spinlock_t spinlock;
 924
 925        /*
 926         * Measures average tape speed
 927         */
 928        unsigned long avg_time;
 929        int avg_size;
 930        int avg_speed;
 931
 932        /* last sense information */
 933        idetape_request_sense_result_t sense;
 934
 935        char vendor_id[10];
 936        char product_id[18];
 937        char firmware_revision[6];
 938        int firmware_revision_num;
 939
 940        /* the door is currently locked */
 941        int door_locked;
 942        /* the tape hardware is write protected */
 943        char drv_write_prot;
 944        /* the tape is write protected (hardware or opened as read-only) */
 945        char write_prot;
 946
 947        /*
 948         * Limit the number of times a request can
 949         * be postponed, to avoid an infinite postpone
 950         * deadlock.
 951         */
 952        /* request postpone count limit */
 953        int postpone_cnt;
 954
 955        /*
 956         * Measures number of frames:
 957         *
 958         * 1. written/read to/from the driver pipeline (pipeline_head).
 959         * 2. written/read to/from the tape buffers (idetape_bh).
 960         * 3. written/read by the tape to/from the media (tape_head).
 961         */
 962        int pipeline_head;
 963        int buffer_head;
 964        int tape_head;
 965        int last_tape_head;
 966
 967        /*
 968         * Speed control at the tape buffers input/output
 969         */
 970        unsigned long insert_time;
 971        int insert_size;
 972        int insert_speed;
 973        int max_insert_speed;
 974        int measure_insert_time;
 975
 976        /*
 977         * Measure tape still time, in milliseconds
 978         */
 979        unsigned long tape_still_time_begin;
 980        int tape_still_time;
 981
 982        /*
 983         * Speed regulation negative feedback loop
 984         */
 985        int speed_control;
 986        int pipeline_head_speed;
 987        int controlled_pipeline_head_speed;
 988        int uncontrolled_pipeline_head_speed;
 989        int controlled_last_pipeline_head;
 990        int uncontrolled_last_pipeline_head;
 991        unsigned long uncontrolled_pipeline_head_time;
 992        unsigned long controlled_pipeline_head_time;
 993        int controlled_previous_pipeline_head;
 994        int uncontrolled_previous_pipeline_head;
 995        unsigned long controlled_previous_head_time;
 996        unsigned long uncontrolled_previous_head_time;
 997        int restart_speed_control_req;
 998
 999        /*
1000         * Debug_level determines amount of debugging output;
1001         * can be changed using /proc/ide/hdx/settings
1002         * 0 : almost no debugging output
1003         * 1 : 0+output errors only
1004         * 2 : 1+output all sensekey/asc
1005         * 3 : 2+follow all chrdev related procedures
1006         * 4 : 3+follow all procedures
1007         * 5 : 4+include pc_stack rq_stack info
1008         * 6 : 5+USE_COUNT updates
1009         */
1010         int debug_level; 
1011} idetape_tape_t;
1012
1013static DEFINE_MUTEX(idetape_ref_mutex);
1014
1015static struct class *idetape_sysfs_class;
1016
1017#define to_ide_tape(obj) container_of(obj, struct ide_tape_obj, kref)
1018
1019#define ide_tape_g(disk) \
1020        container_of((disk)->private_data, struct ide_tape_obj, driver)
1021
1022static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
1023{
1024        struct ide_tape_obj *tape = NULL;
1025
1026        mutex_lock(&idetape_ref_mutex);
1027        tape = ide_tape_g(disk);
1028        if (tape)
1029                kref_get(&tape->kref);
1030        mutex_unlock(&idetape_ref_mutex);
1031        return tape;
1032}
1033
1034static void ide_tape_release(struct kref *);
1035
1036static void ide_tape_put(struct ide_tape_obj *tape)
1037{
1038        mutex_lock(&idetape_ref_mutex);
1039        kref_put(&tape->kref, ide_tape_release);
1040        mutex_unlock(&idetape_ref_mutex);
1041}
1042
1043/*
1044 *      Tape door status
1045 */
1046#define DOOR_UNLOCKED                   0
1047#define DOOR_LOCKED                     1
1048#define DOOR_EXPLICITLY_LOCKED          2
1049
1050/*
1051 *      Tape flag bits values.
1052 */
1053#define IDETAPE_IGNORE_DSC              0
1054#define IDETAPE_ADDRESS_VALID           1       /* 0 When the tape position is unknown */
1055#define IDETAPE_BUSY                    2       /* Device already opened */
1056#define IDETAPE_PIPELINE_ERROR          3       /* Error detected in a pipeline stage */
1057#define IDETAPE_DETECT_BS               4       /* Attempt to auto-detect the current user block size */
1058#define IDETAPE_FILEMARK                5       /* Currently on a filemark */
1059#define IDETAPE_DRQ_INTERRUPT           6       /* DRQ interrupt device */
1060#define IDETAPE_READ_ERROR              7
1061#define IDETAPE_PIPELINE_ACTIVE         8       /* pipeline active */
1062/* 0 = no tape is loaded, so we don't rewind after ejecting */
1063#define IDETAPE_MEDIUM_PRESENT          9
1064
1065/*
1066 *      Supported ATAPI tape drives packet commands
1067 */
1068#define IDETAPE_TEST_UNIT_READY_CMD     0x00
1069#define IDETAPE_REWIND_CMD              0x01
1070#define IDETAPE_REQUEST_SENSE_CMD       0x03
1071#define IDETAPE_READ_CMD                0x08
1072#define IDETAPE_WRITE_CMD               0x0a
1073#define IDETAPE_WRITE_FILEMARK_CMD      0x10
1074#define IDETAPE_SPACE_CMD               0x11
1075#define IDETAPE_INQUIRY_CMD             0x12
1076#define IDETAPE_ERASE_CMD               0x19
1077#define IDETAPE_MODE_SENSE_CMD          0x1a
1078#define IDETAPE_MODE_SELECT_CMD         0x15
1079#define IDETAPE_LOAD_UNLOAD_CMD         0x1b
1080#define IDETAPE_PREVENT_CMD             0x1e
1081#define IDETAPE_LOCATE_CMD              0x2b
1082#define IDETAPE_READ_POSITION_CMD       0x34
1083#define IDETAPE_READ_BUFFER_CMD         0x3c
1084#define IDETAPE_SET_SPEED_CMD           0xbb
1085
1086/*
1087 *      Some defines for the READ BUFFER command
1088 */
1089#define IDETAPE_RETRIEVE_FAULTY_BLOCK   6
1090
1091/*
1092 *      Some defines for the SPACE command
1093 */
1094#define IDETAPE_SPACE_OVER_FILEMARK     1
1095#define IDETAPE_SPACE_TO_EOD            3
1096
1097/*
1098 *      Some defines for the LOAD UNLOAD command
1099 */
1100#define IDETAPE_LU_LOAD_MASK            1
1101#define IDETAPE_LU_RETENSION_MASK       2
1102#define IDETAPE_LU_EOT_MASK             4
1103
1104/*
1105 *      Special requests for our block device strategy routine.
1106 *
1107 *      In order to service a character device command, we add special
1108 *      requests to the tail of our block device request queue and wait
1109 *      for their completion.
1110 */
1111
1112enum {
1113        REQ_IDETAPE_PC1         = (1 << 0), /* packet command (first stage) */
1114        REQ_IDETAPE_PC2         = (1 << 1), /* packet command (second stage) */
1115        REQ_IDETAPE_READ        = (1 << 2),
1116        REQ_IDETAPE_WRITE       = (1 << 3),
1117        REQ_IDETAPE_READ_BUFFER = (1 << 4),
1118};
1119
1120/*
1121 *      Error codes which are returned in rq->errors to the higher part
1122 *      of the driver.
1123 */
1124#define IDETAPE_ERROR_GENERAL           101
1125#define IDETAPE_ERROR_FILEMARK          102
1126#define IDETAPE_ERROR_EOD               103
1127
1128/*
1129 *      The following is used to format the general configuration word of
1130 *      the ATAPI IDENTIFY DEVICE command.
1131 */
1132struct idetape_id_gcw { 
1133        unsigned packet_size            :2;     /* Packet Size */
1134        unsigned reserved234            :3;     /* Reserved */
1135        unsigned drq_type               :2;     /* Command packet DRQ type */
1136        unsigned removable              :1;     /* Removable media */
1137        unsigned device_type            :5;     /* Device type */
1138        unsigned reserved13             :1;     /* Reserved */
1139        unsigned protocol               :2;     /* Protocol type */
1140};
1141
1142/*
1143 *      INQUIRY packet command - Data Format (From Table 6-8 of QIC-157C)
1144 */
1145typedef struct {
1146        unsigned        device_type     :5;     /* Peripheral Device Type */
1147        unsigned        reserved0_765   :3;     /* Peripheral Qualifier - Reserved */
1148        unsigned        reserved1_6t0   :7;     /* Reserved */
1149        unsigned        rmb             :1;     /* Removable Medium Bit */
1150        unsigned        ansi_version    :3;     /* ANSI Version */
1151        unsigned        ecma_version    :3;     /* ECMA Version */
1152        unsigned        iso_version     :2;     /* ISO Version */
1153        unsigned        response_format :4;     /* Response Data Format */
1154        unsigned        reserved3_45    :2;     /* Reserved */
1155        unsigned        reserved3_6     :1;     /* TrmIOP - Reserved */
1156        unsigned        reserved3_7     :1;     /* AENC - Reserved */
1157        __u8            additional_length;      /* Additional Length (total_length-4) */
1158        __u8            rsv5, rsv6, rsv7;       /* Reserved */
1159        __u8            vendor_id[8];           /* Vendor Identification */
1160        __u8            product_id[16];         /* Product Identification */
1161        __u8            revision_level[4];      /* Revision Level */
1162        __u8            vendor_specific[20];    /* Vendor Specific - Optional */
1163        __u8            reserved56t95[40];      /* Reserved - Optional */
1164                                                /* Additional information may be returned */
1165} idetape_inquiry_result_t;
1166
1167/*
1168 *      READ POSITION packet command - Data Format (From Table 6-57)
1169 */
1170typedef struct {
1171        unsigned        reserved0_10    :2;     /* Reserved */
1172        unsigned        bpu             :1;     /* Block Position Unknown */    
1173        unsigned        reserved0_543   :3;     /* Reserved */
1174        unsigned        eop             :1;     /* End Of Partition */
1175        unsigned        bop             :1;     /* Beginning Of Partition */
1176        u8              partition;              /* Partition Number */
1177        u8              reserved2, reserved3;   /* Reserved */
1178        u32             first_block;            /* First Block Location */
1179        u32             last_block;             /* Last Block Location (Optional) */
1180        u8              reserved12;             /* Reserved */
1181        u8              blocks_in_buffer[3];    /* Blocks In Buffer - (Optional) */
1182        u32             bytes_in_buffer;        /* Bytes In Buffer (Optional) */
1183} idetape_read_position_result_t;
1184
1185/*
1186 *      Follows structures which are related to the SELECT SENSE / MODE SENSE
1187 *      packet commands. Those packet commands are still not supported
1188 *      by ide-tape.
1189 */
1190#define IDETAPE_BLOCK_DESCRIPTOR        0
1191#define IDETAPE_CAPABILITIES_PAGE       0x2a
1192#define IDETAPE_PARAMTR_PAGE            0x2b   /* Onstream DI-x0 only */
1193#define IDETAPE_BLOCK_SIZE_PAGE         0x30
1194#define IDETAPE_BUFFER_FILLING_PAGE     0x33
1195
1196/*
1197 *      Mode Parameter Header for the MODE SENSE packet command
1198 */
1199typedef struct {
1200        __u8    mode_data_length;       /* Length of the following data transfer */
1201        __u8    medium_type;            /* Medium Type */
1202        __u8    dsp;                    /* Device Specific Parameter */
1203        __u8    bdl;                    /* Block Descriptor Length */
1204#if 0
1205        /* data transfer page */
1206        __u8    page_code       :6;
1207        __u8    reserved0_6     :1;
1208        __u8    ps              :1;     /* parameters saveable */
1209        __u8    page_length;            /* page Length == 0x02 */
1210        __u8    reserved2;
1211        __u8    read32k         :1;     /* 32k blk size (data only) */
1212        __u8    read32k5        :1;     /* 32.5k blk size (data&AUX) */
1213        __u8    reserved3_23    :2;
1214        __u8    write32k        :1;     /* 32k blk size (data only) */
1215        __u8    write32k5       :1;     /* 32.5k blk size (data&AUX) */
1216        __u8    reserved3_6     :1;
1217        __u8    streaming       :1;     /* streaming mode enable */
1218#endif
1219} idetape_mode_parameter_header_t;
1220
1221/*
1222 *      Mode Parameter Block Descriptor the MODE SENSE packet command
1223 *
1224 *      Support for block descriptors is optional.
1225 */
1226typedef struct {
1227        __u8            density_code;           /* Medium density code */
1228        __u8            blocks[3];              /* Number of blocks */
1229        __u8            reserved4;              /* Reserved */
1230        __u8            length[3];              /* Block Length */
1231} idetape_parameter_block_descriptor_t;
1232
1233/*
1234 *      The Data Compression Page, as returned by the MODE SENSE packet command.
1235 */
1236typedef struct {
1237        unsigned        page_code       :6;     /* Page Code - Should be 0xf */
1238        unsigned        reserved0       :1;     /* Reserved */
1239        unsigned        ps              :1;
1240        __u8            page_length;            /* Page Length - Should be 14 */
1241        unsigned        reserved2       :6;     /* Reserved */
1242        unsigned        dcc             :1;     /* Data Compression Capable */
1243        unsigned        dce             :1;     /* Data Compression Enable */
1244        unsigned        reserved3       :5;     /* Reserved */
1245        unsigned        red             :2;     /* Report Exception on Decompression */
1246        unsigned        dde             :1;     /* Data Decompression Enable */
1247        __u32           ca;                     /* Compression Algorithm */
1248        __u32           da;                     /* Decompression Algorithm */
1249        __u8            reserved[4];            /* Reserved */
1250} idetape_data_compression_page_t;
1251
1252/*
1253 *      The Medium Partition Page, as returned by the MODE SENSE packet command.
1254 */
1255typedef struct {
1256        unsigned        page_code       :6;     /* Page Code - Should be 0x11 */
1257        unsigned        reserved1_6     :1;     /* Reserved */
1258        unsigned        ps              :1;
1259        __u8            page_length;            /* Page Length - Should be 6 */
1260        __u8            map;                    /* Maximum Additional Partitions - Should be 0 */
1261        __u8            apd;                    /* Additional Partitions Defined - Should be 0 */
1262        unsigned        reserved4_012   :3;     /* Reserved */
1263        unsigned        psum            :2;     /* Should be 0 */
1264        unsigned        idp             :1;     /* Should be 0 */
1265        unsigned        sdp             :1;     /* Should be 0 */
1266        unsigned        fdp             :1;     /* Fixed Data Partitions */
1267        __u8            mfr;                    /* Medium Format Recognition */
1268        __u8            reserved[2];            /* Reserved */
1269} idetape_medium_partition_page_t;
1270
1271/*
1272 *      Run time configurable parameters.
1273 */
1274typedef struct {
1275        int     dsc_rw_frequency;
1276        int     dsc_media_access_frequency;
1277        int     nr_stages;
1278} idetape_config_t;
1279
1280/*
1281 *      The variables below are used for the character device interface.
1282 *      Additional state variables are defined in our ide_drive_t structure.
1283 */
1284static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];
1285
1286#define ide_tape_f(file) ((file)->private_data)
1287
1288static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
1289{
1290        struct ide_tape_obj *tape = NULL;
1291
1292        mutex_lock(&idetape_ref_mutex);
1293        tape = idetape_devs[i];
1294        if (tape)
1295                kref_get(&tape->kref);
1296        mutex_unlock(&idetape_ref_mutex);
1297        return tape;
1298}
1299
1300/*
1301 *      Function declarations
1302 *
1303 */
1304static int idetape_chrdev_release (struct inode *inode, struct file *filp);
1305static void idetape_write_release (ide_drive_t *drive, unsigned int minor);
1306
1307/*
1308 * Too bad. The drive wants to send us data which we are not ready to accept.
1309 * Just throw it away.
1310 */
1311static void idetape_discard_data (ide_drive_t *drive, unsigned int bcount)
1312{
1313        while (bcount--)
1314                (void) HWIF(drive)->INB(IDE_DATA_REG);
1315}
1316
1317static void idetape_input_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1318{
1319        struct idetape_bh *bh = pc->bh;
1320        int count;
1321
1322        while (bcount) {
1323#if IDETAPE_DEBUG_BUGS
1324                if (bh == NULL) {
1325                        printk(KERN_ERR "ide-tape: bh == NULL in "
1326                                "idetape_input_buffers\n");
1327                        idetape_discard_data(drive, bcount);
1328                        return;
1329                }
1330#endif /* IDETAPE_DEBUG_BUGS */
1331                count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), bcount);
1332                HWIF(drive)->atapi_input_bytes(drive, bh->b_data + atomic_read(&bh->b_count), count);
1333                bcount -= count;
1334                atomic_add(count, &bh->b_count);
1335                if (atomic_read(&bh->b_count) == bh->b_size) {
1336                        bh = bh->b_reqnext;
1337                        if (bh)
1338                                atomic_set(&bh->b_count, 0);
1339                }
1340        }
1341        pc->bh = bh;
1342}
1343
1344static void idetape_output_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
1345{
1346        struct idetape_bh *bh = pc->bh;
1347        int count;
1348
1349        while (bcount) {
1350#if IDETAPE_DEBUG_BUGS
1351                if (bh == NULL) {
1352                        printk(KERN_ERR "ide-tape: bh == NULL in "
1353                                "idetape_output_buffers\n");
1354                        return;
1355                }
1356#endif /* IDETAPE_DEBUG_BUGS */
1357                count = min((unsigned int)pc->b_count, (unsigned int)bcount);
1358                HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
1359                bcount -= count;
1360                pc->b_data += count;
1361                pc->b_count -= count;
1362                if (!pc->b_count) {
1363                        pc->bh = bh = bh->b_reqnext;
1364                        if (bh) {
1365                                pc->b_data = bh->b_data;
1366                                pc->b_count = atomic_read(&bh->b_count);
1367                        }
1368                }
1369        }
1370}
1371
1372static void idetape_update_buffers (idetape_pc_t *pc)
1373{
1374        struct idetape_bh *bh = pc->bh;
1375        int count;
1376        unsigned int bcount = pc->actually_transferred;
1377
1378        if (test_bit(PC_WRITING, &pc->flags))
1379                return;
1380        while (bcount) {
1381#if IDETAPE_DEBUG_BUGS
1382                if (bh == NULL) {
1383                        printk(KERN_ERR "ide-tape: bh == NULL in "
1384                                "idetape_update_buffers\n");
1385                        return;
1386                }
1387#endif /* IDETAPE_DEBUG_BUGS */
1388                count = min((unsigned int)bh->b_size, (unsigned int)bcount);
1389                atomic_set(&bh->b_count, count);
1390                if (atomic_read(&bh->b_count) == bh->b_size)
1391                        bh = bh->b_reqnext;
1392                bcount -= count;
1393        }
1394        pc->bh = bh;
1395}
1396
1397/*
1398 *      idetape_next_pc_storage returns a pointer to a place in which we can
1399 *      safely store a packet command, even though we intend to leave the
1400 *      driver. A storage space for a maximum of IDETAPE_PC_STACK packet
1401 *      commands is allocated at initialization time.
1402 */
1403static idetape_pc_t *idetape_next_pc_storage (ide_drive_t *drive)
1404{
1405        idetape_tape_t *tape = drive->driver_data;
1406
1407#if IDETAPE_DEBUG_LOG
1408        if (tape->debug_level >= 5)
1409                printk(KERN_INFO "ide-tape: pc_stack_index=%d\n",
1410                        tape->pc_stack_index);
1411#endif /* IDETAPE_DEBUG_LOG */
1412        if (tape->pc_stack_index == IDETAPE_PC_STACK)
1413                tape->pc_stack_index=0;
1414        return (&tape->pc_stack[tape->pc_stack_index++]);
1415}
1416
1417/*
1418 *      idetape_next_rq_storage is used along with idetape_next_pc_storage.
1419 *      Since we queue packet commands in the request queue, we need to
1420 *      allocate a request, along with the allocation of a packet command.
1421 */
1422 
1423/**************************************************************
1424 *                                                            *
1425 *  This should get fixed to use kmalloc(.., GFP_ATOMIC)      *
1426 *  followed later on by kfree().   -ml                       *
1427 *                                                            *
1428 **************************************************************/
1429 
1430static struct request *idetape_next_rq_storage (ide_drive_t *drive)
1431{
1432        idetape_tape_t *tape = drive->driver_data;
1433
1434#if IDETAPE_DEBUG_LOG
1435        if (tape->debug_level >= 5)
1436                printk(KERN_INFO "ide-tape: rq_stack_index=%d\n",
1437                        tape->rq_stack_index);
1438#endif /* IDETAPE_DEBUG_LOG */
1439        if (tape->rq_stack_index == IDETAPE_PC_STACK)
1440                tape->rq_stack_index=0;
1441        return (&tape->rq_stack[tape->rq_stack_index++]);
1442}
1443
1444/*
1445 *      idetape_init_pc initializes a packet command.
1446 */
1447static void idetape_init_pc (idetape_pc_t *pc)
1448{
1449        memset(pc->c, 0, 12);
1450        pc->retries = 0;
1451        pc->flags = 0;
1452        pc->request_transfer = 0;
1453        pc->buffer = pc->pc_buffer;
1454        pc->buffer_size = IDETAPE_PC_BUFFER_SIZE;
1455        pc->bh = NULL;
1456        pc->b_data = NULL;
1457}
1458
1459/*
1460 *      idetape_analyze_error is called on each failed packet command retry
1461 *      to analyze the request sense. We currently do not utilize this
1462 *      information.
1463 */
1464static void idetape_analyze_error (ide_drive_t *drive, idetape_request_sense_result_t *result)
1465{
1466        idetape_tape_t *tape = drive->driver_data;
1467        idetape_pc_t *pc = tape->failed_pc;
1468
1469        tape->sense     = *result;
1470        tape->sense_key = result->sense_key;
1471        tape->asc       = result->asc;
1472        tape->ascq      = result->ascq;
1473#if IDETAPE_DEBUG_LOG
1474        /*
1475         *      Without debugging, we only log an error if we decided to
1476         *      give up retrying.
1477         */
1478        if (tape->debug_level >= 1)
1479                printk(KERN_INFO "ide-tape: pc = %x, sense key = %x, "
1480                        "asc = %x, ascq = %x\n",
1481                        pc->c[0], result->sense_key,
1482                        result->asc, result->ascq);
1483#endif /* IDETAPE_DEBUG_LOG */
1484
1485        /*
1486         *      Correct pc->actually_transferred by asking the tape.
1487         */
1488        if (test_bit(PC_DMA_ERROR, &pc->flags)) {
1489                pc->actually_transferred = pc->request_transfer - tape->tape_block_size * ntohl(get_unaligned(&result->information));
1490                idetape_update_buffers(pc);
1491        }
1492
1493        /*
1494         * If error was the result of a zero-length read or write command,
1495         * with sense key=5, asc=0x22, ascq=0, let it slide.  Some drives
1496         * (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
1497         */
1498        if ((pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD)
1499            && pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) { /* length==0 */
1500                if (result->sense_key == 5) {
1501                        /* don't report an error, everything's ok */
1502                        pc->error = 0;
1503                        /* don't retry read/write */
1504                        set_bit(PC_ABORT, &pc->flags);
1505                }
1506        }
1507        if (pc->c[0] == IDETAPE_READ_CMD && result->filemark) {
1508                pc->error = IDETAPE_ERROR_FILEMARK;
1509                set_bit(PC_ABORT, &pc->flags);
1510        }
1511        if (pc->c[0] == IDETAPE_WRITE_CMD) {
1512                if (result->eom ||
1513                    (result->sense_key == 0xd && result->asc == 0x0 &&
1514                     result->ascq == 0x2)) {
1515                        pc->error = IDETAPE_ERROR_EOD;
1516                        set_bit(PC_ABORT, &pc->flags);
1517                }
1518        }
1519        if (pc->c[0] == IDETAPE_READ_CMD || pc->c[0] == IDETAPE_WRITE_CMD) {
1520                if (result->sense_key == 8) {
1521                        pc->error = IDETAPE_ERROR_EOD;
1522                        set_bit(PC_ABORT, &pc->flags);
1523                }
1524                if (!test_bit(PC_ABORT, &pc->flags) &&
1525                    pc->actually_transferred)
1526                        pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
1527        }
1528}
1529
1530/*
1531 * idetape_active_next_stage will declare the next stage as "active".
1532 */
1533static void idetape_active_next_stage (ide_drive_t *drive)
1534{
1535        idetape_tape_t *tape = drive->driver_data;
1536        idetape_stage_t *stage = tape->next_stage;
1537        struct request *rq = &stage->rq;
1538
1539#if IDETAPE_DEBUG_LOG
1540        if (tape->debug_level >= 4)
1541                printk(KERN_INFO "ide-tape: Reached idetape_active_next_stage\n");
1542#endif /* IDETAPE_DEBUG_LOG */
1543#if IDETAPE_DEBUG_BUGS
1544        if (stage == NULL) {
1545                printk(KERN_ERR "ide-tape: bug: Trying to activate a non existing stage\n");
1546                return;
1547        }
1548#endif /* IDETAPE_DEBUG_BUGS */ 
1549
1550        rq->rq_disk = tape->disk;
1551        rq->buffer = NULL;
1552        rq->special = (void *)stage->bh;
1553        tape->active_data_request = rq;
1554        tape->active_stage = stage;
1555        tape->next_stage = stage->next;
1556}
1557
1558/*
1559 *      idetape_increase_max_pipeline_stages is a part of the feedback
1560 *      loop which tries to find the optimum number of stages. In the
1561 *      feedback loop, we are starting from a minimum maximum number of
1562 *      stages, and if we sense that the pipeline is empty, we try to
1563 *      increase it, until we reach the user compile time memory limit.
1564 */
1565static void idetape_increase_max_pipeline_stages (ide_drive_t *drive)
1566{
1567        idetape_tape_t *tape = drive->driver_data;
1568        int increase = (tape->max_pipeline - tape->min_pipeline) / 10;
1569        
1570#if IDETAPE_DEBUG_LOG
1571        if (tape->debug_level >= 4)
1572                printk (KERN_INFO "ide-tape: Reached idetape_increase_max_pipeline_stages\n");
1573#endif /* IDETAPE_DEBUG_LOG */
1574
1575        tape->max_stages += max(increase, 1);
1576        tape->max_stages = max(tape->max_stages, tape->min_pipeline);
1577        tape->max_stages = min(tape->max_stages, tape->max_pipeline);
1578}
1579
1580/*
1581 *      idetape_kfree_stage calls kfree to completely free a stage, along with
1582 *      its related buffers.
1583 */
1584static void __idetape_kfree_stage (idetape_stage_t *stage)
1585{
1586        struct idetape_bh *prev_bh, *bh = stage->bh;
1587        int size;
1588
1589        while (bh != NULL) {
1590                if (bh->b_data != NULL) {
1591                        size = (int) bh->b_size;
1592                        while (size > 0) {
1593                                free_page((unsigned long) bh->b_data);
1594                                size -= PAGE_SIZE;
1595                                bh->b_data += PAGE_SIZE;
1596                        }
1597                }
1598                prev_bh = bh;
1599                bh = bh->b_reqnext;
1600                kfree(prev_bh);
1601        }
1602        kfree(stage);
1603}
1604
1605static void idetape_kfree_stage (idetape_tape_t *tape, idetape_stage_t *stage)
1606{
1607        __idetape_kfree_stage(stage);
1608}
1609
1610/*
1611 *      idetape_remove_stage_head removes tape->first_stage from the pipeline.
1612 *      The caller should avoid race conditions.
1613 */
1614static void idetape_remove_stage_head (ide_drive_t *drive)
1615{
1616        idetape_tape_t *tape = drive->driver_data;
1617        idetape_stage_t *stage;
1618        
1619#if IDETAPE_DEBUG_LOG
1620        if (tape->debug_level >= 4)
1621                printk(KERN_INFO "ide-tape: Reached idetape_remove_stage_head\n");
1622#endif /* IDETAPE_DEBUG_LOG */
1623#if IDETAPE_DEBUG_BUGS
1624        if (tape->first_stage == NULL) {
1625                printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
1626                return;         
1627        }
1628        if (tape->active_stage == tape->first_stage) {
1629                printk(KERN_ERR "ide-tape: bug: Trying to free our active pipeline stage\n");
1630                return;
1631        }
1632#endif /* IDETAPE_DEBUG_BUGS */
1633        stage = tape->first_stage;
1634        tape->first_stage = stage->next;
1635        idetape_kfree_stage(tape, stage);
1636        tape->nr_stages--;
1637        if (tape->first_stage == NULL) {
1638                tape->last_stage = NULL;
1639#if IDETAPE_DEBUG_BUGS
1640                if (tape->next_stage != NULL)
1641                        printk(KERN_ERR "ide-tape: bug: tape->next_stage != NULL\n");
1642                if (tape->nr_stages)
1643                        printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 now\n");
1644#endif /* IDETAPE_DEBUG_BUGS */
1645        }
1646}
1647
1648/*
1649 * This will free all the pipeline stages starting from new_last_stage->next
1650 * to the end of the list, and point tape->last_stage to new_last_stage.
1651 */
1652static void idetape_abort_pipeline(ide_drive_t *drive,
1653                                   idetape_stage_t *new_last_stage)
1654{
1655        idetape_tape_t *tape = drive->driver_data;
1656        idetape_stage_t *stage = new_last_stage->next;
1657        idetape_stage_t *nstage;
1658
1659#if IDETAPE_DEBUG_LOG
1660        if (tape->debug_level >= 4)
1661                printk(KERN_INFO "ide-tape: %s: idetape_abort_pipeline called\n", tape->name);
1662#endif
1663        while (stage) {
1664                nstage = stage->next;
1665                idetape_kfree_stage(tape, stage);
1666                --tape->nr_stages;
1667                --tape->nr_pending_stages;
1668                stage = nstage;
1669        }
1670        if (new_last_stage)
1671                new_last_stage->next = NULL;
1672        tape->last_stage = new_last_stage;
1673        tape->next_stage = NULL;
1674}
1675
1676/*
1677 *      idetape_end_request is used to finish servicing a request, and to
1678 *      insert a pending pipeline request into the main device queue.
1679 */
1680static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
1681{
1682        struct request *rq = HWGROUP(drive)->rq;
1683        idetape_tape_t *tape = drive->driver_data;
1684        unsigned long flags;
1685        int error;
1686        int remove_stage = 0;
1687        idetape_stage_t *active_stage;
1688
1689#if IDETAPE_DEBUG_LOG
1690        if (tape->debug_level >= 4)
1691        printk(KERN_INFO "ide-tape: Reached idetape_end_request\n");
1692#endif /* IDETAPE_DEBUG_LOG */
1693
1694        switch (uptodate) {
1695                case 0: error = IDETAPE_ERROR_GENERAL; break;
1696                case 1: error = 0; break;
1697                default: error = uptodate;
1698        }
1699        rq->errors = error;
1700        if (error)
1701                tape->failed_pc = NULL;
1702
1703        spin_lock_irqsave(&tape->spinlock, flags);
1704
1705        /* The request was a pipelined data transfer request */
1706        if (tape->active_data_request == rq) {
1707                active_stage = tape->active_stage;
1708                tape->active_stage = NULL;
1709                tape->active_data_request = NULL;
1710                tape->nr_pending_stages--;
1711                if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
1712                        remove_stage = 1;
1713                        if (error) {
1714                                set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1715                                if (error == IDETAPE_ERROR_EOD)
1716                                        idetape_abort_pipeline(drive, active_stage);
1717                        }
1718                } else if (rq->cmd[0] & REQ_IDETAPE_READ) {
1719                        if (error == IDETAPE_ERROR_EOD) {
1720                                set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
1721                                idetape_abort_pipeline(drive, active_stage);
1722                        }
1723                }
1724                if (tape->next_stage != NULL) {
1725                        idetape_active_next_stage(drive);
1726
1727                        /*
1728                         * Insert the next request into the request queue.
1729                         */
1730                        (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
1731                } else if (!error) {
1732                                idetape_increase_max_pipeline_stages(drive);
1733                }
1734        }
1735        ide_end_drive_cmd(drive, 0, 0);
1736//      blkdev_dequeue_request(rq);
1737//      drive->rq = NULL;
1738//      end_that_request_last(rq);
1739
1740        if (remove_stage)
1741                idetape_remove_stage_head(drive);
1742        if (tape->active_data_request == NULL)
1743                clear_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
1744        spin_unlock_irqrestore(&tape->spinlock, flags);
1745        return 0;
1746}
1747
1748static ide_startstop_t idetape_request_sense_callback (ide_drive_t *drive)
1749{
1750        idetape_tape_t *tape = drive->driver_data;
1751
1752#if IDETAPE_DEBUG_LOG
1753        if (tape->debug_level >= 4)
1754                printk(KERN_INFO "ide-tape: Reached idetape_request_sense_callback\n");
1755#endif /* IDETAPE_DEBUG_LOG */
1756        if (!tape->pc->error) {
1757                idetape_analyze_error(drive, (idetape_request_sense_result_t *) tape->pc->buffer);
1758                idetape_end_request(drive, 1, 0);
1759        } else {
1760                printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - Aborting request!\n");
1761                idetape_end_request(drive, 0, 0);
1762        }
1763        return ide_stopped;
1764}
1765
1766static void idetape_create_request_sense_cmd (idetape_pc_t *pc)
1767{
1768        idetape_init_pc(pc);    
1769        pc->c[0] = IDETAPE_REQUEST_SENSE_CMD;
1770        pc->c[4] = 20;
1771        pc->request_transfer = 20;
1772        pc->callback = &idetape_request_sense_callback;
1773}
1774
1775static void idetape_init_rq(struct request *rq, u8 cmd)
1776{
1777        memset(rq, 0, sizeof(*rq));
1778        rq->cmd_type = REQ_TYPE_SPECIAL;
1779        rq->cmd[0] = cmd;
1780}
1781
1782/*
1783 *      idetape_queue_pc_head generates a new packet command request in front
1784 *      of the request queue, before the current request, so that it will be
1785 *      processed immediately, on the next pass through the driver.
1786 *
1787 *      idetape_queue_pc_head is called from the request handling part of
1788 *      the driver (the "bottom" part). Safe storage for the request should
1789 *      be allocated with idetape_next_pc_storage and idetape_next_rq_storage
1790 *      before calling idetape_queue_pc_head.
1791 *
1792 *      Memory for those requests is pre-allocated at initialization time, and
1793 *      is limited to IDETAPE_PC_STACK requests. We assume that we have enough
1794 *      space for the maximum possible number of inter-dependent packet commands.
1795 *
1796 *      The higher level of the driver - The ioctl handler and the character
1797 *      device handling functions should queue request to the lower level part
1798 *      and wait for their completion using idetape_queue_pc_tail or
1799 *      idetape_queue_rw_tail.
1800 */
1801static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
1802{
1803        struct ide_tape_obj *tape = drive->driver_data;
1804
1805        idetape_init_rq(rq, REQ_IDETAPE_PC1);
1806        rq->buffer = (char *) pc;
1807        rq->rq_disk = tape->disk;
1808        (void) ide_do_drive_cmd(drive, rq, ide_preempt);
1809}
1810
1811/*
1812 *      idetape_retry_pc is called when an error was detected during the
1813 *      last packet command. We queue a request sense packet command in
1814 *      the head of the request list.
1815 */
1816static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
1817{
1818        idetape_tape_t *tape = drive->driver_data;
1819        idetape_pc_t *pc;
1820        struct request *rq;
1821        atapi_error_t error;
1822
1823        error.all = HWIF(drive)->INB(IDE_ERROR_REG);
1824        pc = idetape_next_pc_storage(drive);
1825        rq = idetape_next_rq_storage(drive);
1826        idetape_create_request_sense_cmd(pc);
1827        set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
1828        idetape_queue_pc_head(drive, pc, rq);
1829        return ide_stopped;
1830}
1831
1832/*
1833 *      idetape_postpone_request postpones the current request so that
1834 *      ide.c will be able to service requests from another device on
1835 *      the same hwgroup while we are polling for DSC.
1836 */
1837static void idetape_postpone_request (ide_drive_t *drive)
1838{
1839        idetape_tape_t *tape = drive->driver_data;
1840
1841#if IDETAPE_DEBUG_LOG
1842        if (tape->debug_level >= 4)
1843                printk(KERN_INFO "ide-tape: idetape_postpone_request\n");
1844#endif
1845        tape->postponed_rq = HWGROUP(drive)->rq;
1846        ide_stall_queue(drive, tape->dsc_polling_frequency);
1847}
1848
1849/*
1850 *      idetape_pc_intr is the usual interrupt handler which will be called
1851 *      during a packet command. We will transfer some of the data (as
1852 *      requested by the drive) and will re-point interrupt handler to us.
1853 *      When data transfer is finished, we will act according to the
1854 *      algorithm described before idetape_issue_packet_command.
1855 *
1856 */
1857static ide_startstop_t idetape_pc_intr (ide_drive_t *drive)
1858{
1859        ide_hwif_t *hwif = drive->hwif;
1860        idetape_tape_t *tape = drive->driver_data;
1861        atapi_status_t status;
1862        atapi_bcount_t bcount;
1863        atapi_ireason_t ireason;
1864        idetape_pc_t *pc = tape->pc;
1865
1866        unsigned int temp;
1867#if SIMULATE_ERRORS
1868        static int error_sim_count = 0;
1869#endif
1870
1871#if IDETAPE_DEBUG_LOG
1872        if (tape->debug_level >= 4)
1873                printk(KERN_INFO "ide-tape: Reached idetape_pc_intr "
1874                                "interrupt handler\n");
1875#endif /* IDETAPE_DEBUG_LOG */  
1876
1877        /* Clear the interrupt */
1878        status.all = HWIF(drive)->INB(IDE_STATUS_REG);
1879
1880        if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1881                if (HWIF(drive)->ide_dma_end(drive) || status.b.check) {
1882                        /*
1883                         * A DMA error is sometimes expected. For example,
1884                         * if the tape is crossing a filemark during a
1885                         * READ command, it will issue an irq and position
1886                         * itself before the filemark, so that only a partial
1887                         * data transfer will occur (which causes the DMA
1888                         * error). In that case, we will later ask the tape
1889                         * how much bytes of the original request were
1890                         * actually transferred (we can't receive that
1891                         * information from the DMA engine on most chipsets).
1892                         */
1893
1894                        /*
1895                         * On the contrary, a DMA error is never expected;
1896                         * it usually indicates a hardware error or abort.
1897                         * If the tape crosses a filemark during a READ
1898                         * command, it will issue an irq and position itself
1899                         * after the filemark (not before). Only a partial
1900                         * data transfer will occur, but no DMA error.
1901                         * (AS, 19 Apr 2001)
1902                         */
1903                        set_bit(PC_DMA_ERROR, &pc->flags);
1904                } else {
1905                        pc->actually_transferred = pc->request_transfer;
1906                        idetape_update_buffers(pc);
1907                }
1908#if IDETAPE_DEBUG_LOG
1909                if (tape->debug_level >= 4)
1910                        printk(KERN_INFO "ide-tape: DMA finished\n");
1911#endif /* IDETAPE_DEBUG_LOG */
1912        }
1913
1914        /* No more interrupts */
1915        if (!status.b.drq) {
1916#if IDETAPE_DEBUG_LOG
1917                if (tape->debug_level >= 2)
1918                        printk(KERN_INFO "ide-tape: Packet command completed, %d bytes transferred\n", pc->actually_transferred);
1919#endif /* IDETAPE_DEBUG_LOG */
1920                clear_bit(PC_DMA_IN_PROGRESS, &pc->flags);
1921
1922                local_irq_enable();
1923
1924#if SIMULATE_ERRORS
1925                if ((pc->c[0] == IDETAPE_WRITE_CMD ||
1926                     pc->c[0] == IDETAPE_READ_CMD) &&
1927                    (++error_sim_count % 100) == 0) {
1928                        printk(KERN_INFO "ide-tape: %s: simulating error\n",
1929                                tape->name);
1930                        status.b.check = 1;
1931                }
1932#endif
1933                if (status.b.check && pc->c[0] == IDETAPE_REQUEST_SENSE_CMD)
1934                        status.b.check = 0;
1935                if (status.b.check || test_bit(PC_DMA_ERROR, &pc->flags)) {     /* Error detected */
1936#if IDETAPE_DEBUG_LOG
1937                        if (tape->debug_level >= 1)
1938                                printk(KERN_INFO "ide-tape: %s: I/O error\n",
1939                                        tape->name);
1940#endif /* IDETAPE_DEBUG_LOG */
1941                        if (pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
1942                                printk(KERN_ERR "ide-tape: I/O error in request sense command\n");
1943                                return ide_do_reset(drive);
1944                        }
1945#if IDETAPE_DEBUG_LOG
1946                        if (tape->debug_level >= 1)
1947                                printk(KERN_INFO "ide-tape: [cmd %x]: check condition\n", pc->c[0]);
1948#endif
1949                        /* Retry operation */
1950                        return idetape_retry_pc(drive);
1951                }
1952                pc->error = 0;
1953                if (test_bit(PC_WAIT_FOR_DSC, &pc->flags) &&
1954                    !status.b.dsc) {
1955                        /* Media access command */
1956                        tape->dsc_polling_start = jiffies;
1957                        tape->dsc_polling_frequency = IDETAPE_DSC_MA_FAST;
1958                        tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
1959                        /* Allow ide.c to handle other requests */
1960                        idetape_postpone_request(drive);
1961                        return ide_stopped;
1962                }
1963                if (tape->failed_pc == pc)
1964                        tape->failed_pc = NULL;
1965                /* Command finished - Call the callback function */
1966                return pc->callback(drive);
1967        }
1968        if (test_and_clear_bit(PC_DMA_IN_PROGRESS, &pc->flags)) {
1969                printk(KERN_ERR "ide-tape: The tape wants to issue more "
1970                                "interrupts in DMA mode\n");
1971                printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
1972                ide_dma_off(drive);
1973                return ide_do_reset(drive);
1974        }
1975        /* Get the number of bytes to transfer on this interrupt. */
1976        bcount.b.high = hwif->INB(IDE_BCOUNTH_REG);
1977        bcount.b.low = hwif->INB(IDE_BCOUNTL_REG);
1978
1979        ireason.all = hwif->INB(IDE_IREASON_REG);
1980
1981        if (ireason.b.cod) {
1982                printk(KERN_ERR "ide-tape: CoD != 0 in idetape_pc_intr\n");
1983                return ide_do_reset(drive);
1984        }
1985        if (ireason.b.io == test_bit(PC_WRITING, &pc->flags)) {
1986                /* Hopefully, we will never get here */
1987                printk(KERN_ERR "ide-tape: We wanted to %s, ",
1988                        ireason.b.io ? "Write":"Read");
1989                printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
1990                        ireason.b.io ? "Read":"Write");
1991                return ide_do_reset(drive);
1992        }
1993        if (!test_bit(PC_WRITING, &pc->flags)) {
1994                /* Reading - Check that we have enough space */
1995                temp = pc->actually_transferred + bcount.all;
1996                if (temp > pc->request_transfer) {
1997                        if (temp > pc->buffer_size) {
1998                                printk(KERN_ERR "ide-tape: The tape wants to send us more data than expected - discarding data\n");
1999                                idetape_discard_data(drive, bcount.all);
2000                                ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2001                                return ide_started;
2002                        }
2003#if IDETAPE_DEBUG_LOG
2004                        if (tape->debug_level >= 2)
2005                                printk(KERN_NOTICE "ide-tape: The tape wants to send us more data than expected - allowing transfer\n");
2006#endif /* IDETAPE_DEBUG_LOG */
2007                }
2008        }
2009        if (test_bit(PC_WRITING, &pc->flags)) {
2010                if (pc->bh != NULL)
2011                        idetape_output_buffers(drive, pc, bcount.all);
2012                else
2013                        /* Write the current buffer */
2014                        HWIF(drive)->atapi_output_bytes(drive, pc->current_position, bcount.all);
2015        } else {
2016                if (pc->bh != NULL)
2017                        idetape_input_buffers(drive, pc, bcount.all);
2018                else
2019                        /* Read the current buffer */
2020                        HWIF(drive)->atapi_input_bytes(drive, pc->current_position, bcount.all);
2021        }
2022        /* Update the current position */
2023        pc->actually_transferred += bcount.all;
2024        pc->current_position += bcount.all;
2025#if IDETAPE_DEBUG_LOG
2026        if (tape->debug_level >= 2)
2027                printk(KERN_INFO "ide-tape: [cmd %x] transferred %d bytes on that interrupt\n", pc->c[0], bcount.all);
2028#endif
2029        /* And set the interrupt handler again */
2030        ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2031        return ide_started;
2032}
2033
2034/*
2035 *      Packet Command Interface
2036 *
2037 *      The current Packet Command is available in tape->pc, and will not
2038 *      change until we finish handling it. Each packet command is associated
2039 *      with a callback function that will be called when the command is
2040 *      finished.
2041 *
2042 *      The handling will be done in three stages:
2043 *
2044 *      1.      idetape_issue_packet_command will send the packet command to the
2045 *              drive, and will set the interrupt handler to idetape_pc_intr.
2046 *
2047 *      2.      On each interrupt, idetape_pc_intr will be called. This step
2048 *              will be repeated until the device signals us that no more
2049 *              interrupts will be issued.
2050 *
2051 *      3.      ATAPI Tape media access commands have immediate status with a
2052 *              delayed process. In case of a successful initiation of a
2053 *              media access packet command, the DSC bit will be set when the
2054 *              actual execution of the command is finished. 
2055 *              Since the tape drive will not issue an interrupt, we have to
2056 *              poll for this event. In this case, we define the request as
2057 *              "low priority request" by setting rq_status to
2058 *              IDETAPE_RQ_POSTPONED,   set a timer to poll for DSC and exit
2059 *              the driver.
2060 *
2061 *              ide.c will then give higher priority to requests which
2062 *              originate from the other device, until will change rq_status
2063 *              to RQ_ACTIVE.
2064 *
2065 *      4.      When the packet command is finished, it will be checked for errors.
2066 *
2067 *      5.      In case an error was found, we queue a request sense packet
2068 *              command in front of the request queue and retry the operation
2069 *              up to IDETAPE_MAX_PC_RETRIES times.
2070 *
2071 *      6.      In case no error was found, or we decided to give up and not
2072 *              to retry again, the callback function will be called and then
2073 *              we will handle the next request.
2074 *
2075 */
2076static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
2077{
2078        ide_hwif_t *hwif = drive->hwif;
2079        idetape_tape_t *tape = drive->driver_data;
2080        idetape_pc_t *pc = tape->pc;
2081        atapi_ireason_t ireason;
2082        int retries = 100;
2083        ide_startstop_t startstop;
2084
2085        if (ide_wait_stat(&startstop,drive,DRQ_STAT,BUSY_STAT,WAIT_READY)) {
2086                printk(KERN_ERR "ide-tape: Strange, packet command initiated yet DRQ isn't asserted\n");
2087                return startstop;
2088        }
2089        ireason.all = hwif->INB(IDE_IREASON_REG);
2090        while (retries-- && (!ireason.b.cod || ireason.b.io)) {
2091                printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
2092                                "a packet command, retrying\n");
2093                udelay(100);
2094                ireason.all = hwif->INB(IDE_IREASON_REG);
2095                if (retries == 0) {
2096                        printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
2097                                        "issuing a packet command, ignoring\n");
2098                        ireason.b.cod = 1;
2099                        ireason.b.io = 0;
2100                }
2101        }
2102        if (!ireason.b.cod || ireason.b.io) {
2103                printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
2104                                "a packet command\n");
2105                return ide_do_reset(drive);
2106        }
2107        /* Set the interrupt routine */
2108        ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
2109#ifdef CONFIG_BLK_DEV_IDEDMA
2110        /* Begin DMA, if necessary */
2111        if (test_bit(PC_DMA_IN_PROGRESS, &pc->flags))
2112                hwif->dma_start(drive);
2113#endif
2114        /* Send the actual packet */
2115        HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
2116        return ide_started;
2117}
2118
2119static ide_startstop_t idetape_issue_packet_command (ide_drive_t *drive, idetape_pc_t *pc)
2120{
2121        ide_hwif_t *hwif = drive->hwif;
2122        idetape_tape_t *tape = drive->driver_data;
2123        atapi_bcount_t bcount;
2124        int dma_ok = 0;
2125
2126#if IDETAPE_DEBUG_BUGS
2127        if (tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD &&
2128            pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2129                printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
2130                        "Two request sense in serial were issued\n");
2131        }
2132#endif /* IDETAPE_DEBUG_BUGS */
2133
2134        if (tape->failed_pc == NULL && pc->c[0] != IDETAPE_REQUEST_SENSE_CMD)
2135                tape->failed_pc = pc;
2136        /* Set the current packet command */
2137        tape->pc = pc;
2138
2139        if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
2140            test_bit(PC_ABORT, &pc->flags)) {
2141                /*
2142                 *      We will "abort" retrying a packet command in case
2143                 *      a legitimate error code was received (crossing a
2144                 *      filemark, or end of the media, for example).
2145                 */
2146                if (!test_bit(PC_ABORT, &pc->flags)) {
2147                        if (!(pc->c[0] == IDETAPE_TEST_UNIT_READY_CMD &&
2148                              tape->sense_key == 2 && tape->asc == 4 &&
2149                             (tape->ascq == 1 || tape->ascq == 8))) {
2150                                printk(KERN_ERR "ide-tape: %s: I/O error, "
2151                                                "pc = %2x, key = %2x, "
2152                                                "asc = %2x, ascq = %2x\n",
2153                                                tape->name, pc->c[0],
2154                                                tape->sense_key, tape->asc,
2155                                                tape->ascq);
2156                        }
2157                        /* Giving up */
2158                        pc->error = IDETAPE_ERROR_GENERAL;
2159                }
2160                tape->failed_pc = NULL;
2161                return pc->callback(drive);
2162        }
2163#if IDETAPE_DEBUG_LOG
2164        if (tape->debug_level >= 2)
2165                printk(KERN_INFO "ide-tape: Retry number - %d, cmd = %02X\n", pc->retries, pc->c[0]);
2166#endif /* IDETAPE_DEBUG_LOG */
2167
2168        pc->retries++;
2169        /* We haven't transferred any data yet */
2170        pc->actually_transferred = 0;
2171        pc->current_position = pc->buffer;
2172        /* Request to transfer the entire buffer at once */
2173        bcount.all = pc->request_transfer;
2174
2175        if (test_and_clear_bit(PC_DMA_ERROR, &pc->flags)) {
2176                printk(KERN_WARNING "ide-tape: DMA disabled, "
2177                                "reverting to PIO\n");
2178                ide_dma_off(drive);
2179        }
2180        if (test_bit(PC_DMA_RECOMMENDED, &pc->flags) && drive->using_dma)
2181                dma_ok = !hwif->dma_setup(drive);
2182
2183        if (IDE_CONTROL_REG)
2184                hwif->OUTB(drive->ctl, IDE_CONTROL_REG);
2185        hwif->OUTB(dma_ok ? 1 : 0, IDE_FEATURE_REG);    /* Use PIO/DMA */
2186        hwif->OUTB(bcount.b.high, IDE_BCOUNTH_REG);
2187        hwif->OUTB(bcount.b.low, IDE_BCOUNTL_REG);
2188        hwif->OUTB(drive->select.all, IDE_SELECT_REG);
2189        if (dma_ok)                     /* Will begin DMA later */
2190                set_bit(PC_DMA_IN_PROGRESS, &pc->flags);
2191        if (test_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags)) {
2192                ide_set_handler(drive, &idetape_transfer_pc, IDETAPE_WAIT_CMD, NULL);
2193                hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2194                return ide_started;
2195        } else {
2196                hwif->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG);
2197                return idetape_transfer_pc(drive);
2198        }
2199}
2200
2201/*
2202 *      General packet command callback function.
2203 */
2204static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
2205{
2206        idetape_tape_t *tape = drive->driver_data;
2207        
2208#if IDETAPE_DEBUG_LOG
2209        if (tape->debug_level >= 4)
2210                printk(KERN_INFO "ide-tape: Reached idetape_pc_callback\n");
2211#endif /* IDETAPE_DEBUG_LOG */
2212
2213        idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
2214        return ide_stopped;
2215}
2216
2217/*
2218 *      A mode sense command is used to "sense" tape parameters.
2219 */
2220static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
2221{
2222        idetape_init_pc(pc);
2223        pc->c[0] = IDETAPE_MODE_SENSE_CMD;
2224        if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
2225                pc->c[1] = 8;   /* DBD = 1 - Don't return block descriptors */
2226        pc->c[2] = page_code;
2227        /*
2228         * Changed pc->c[3] to 0 (255 will at best return unused info).
2229         *
2230         * For SCSI this byte is defined as subpage instead of high byte
2231         * of length and some IDE drives seem to interpret it this way
2232         * and return an error when 255 is used.
2233         */
2234        pc->c[3] = 0;
2235        pc->c[4] = 255;         /* (We will just discard data in that case) */
2236        if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
2237                pc->request_transfer = 12;
2238        else if (page_code == IDETAPE_CAPABILITIES_PAGE)
2239                pc->request_transfer = 24;
2240        else
2241                pc->request_transfer = 50;
2242        pc->callback = &idetape_pc_callback;
2243}
2244
2245static void calculate_speeds(ide_drive_t *drive)
2246{
2247        idetape_tape_t *tape = drive->driver_data;
2248        int full = 125, empty = 75;
2249
2250        if (time_after(jiffies, tape->controlled_pipeline_head_time + 120 * HZ)) {
2251                tape->controlled_previous_pipeline_head = tape->controlled_last_pipeline_head;
2252                tape->controlled_previous_head_time = tape->controlled_pipeline_head_time;
2253                tape->controlled_last_pipeline_head = tape->pipeline_head;
2254                tape->controlled_pipeline_head_time = jiffies;
2255        }
2256        if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))
2257                tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_last_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_pipeline_head_time);
2258        else if (time_after(jiffies, tape->controlled_previous_head_time))
2259                tape->controlled_pipeline_head_speed = (tape->pipeline_head - tape->controlled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->controlled_previous_head_time);
2260
2261        if (tape->nr_pending_stages < tape->max_stages /*- 1 */) {
2262                /* -1 for read mode error recovery */
2263                if (time_after(jiffies, tape->uncontrolled_previous_head_time + 10 * HZ)) {
2264                        tape->uncontrolled_pipeline_head_time = jiffies;
2265                        tape->uncontrolled_pipeline_head_speed = (tape->pipeline_head - tape->uncontrolled_previous_pipeline_head) * 32 * HZ / (jiffies - tape->uncontrolled_previous_head_time);
2266                }
2267        } else {
2268                tape->uncontrolled_previous_head_time = jiffies;
2269                tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;
2270                if (time_after(jiffies, tape->uncontrolled_pipeline_head_time + 30 * HZ)) {
2271                        tape->uncontrolled_pipeline_head_time = jiffies;
2272                }
2273        }
2274        tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed, tape->controlled_pipeline_head_speed);
2275        if (tape->speed_control == 0) {
2276                tape->max_insert_speed = 5000;
2277        } else if (tape->speed_control == 1) {
2278                if (tape->nr_pending_stages >= tape->max_stages / 2)
2279                        tape->max_insert_speed = tape->pipeline_head_speed +
2280                                (1100 - tape->pipeline_head_speed) * 2 * (tape->nr_pending_stages - tape->max_stages / 2) / tape->max_stages;
2281                else
2282                        tape->max_insert_speed = 500 +
2283                                (tape->pipeline_head_speed - 500) * 2 * tape->nr_pending_stages / tape->max_stages;
2284                if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)
2285                        tape->max_insert_speed = 5000;
2286        } else if (tape->speed_control == 2) {
2287                tape->max_insert_speed = tape->pipeline_head_speed * empty / 100 +
2288                        (tape->pipeline_head_speed * full / 100 - tape->pipeline_head_speed * empty / 100) * tape->nr_pending_stages / tape->max_stages;
2289        } else
2290                tape->max_insert_speed = tape->speed_control;
2291        tape->max_insert_speed = max(tape->max_insert_speed, 500);
2292}
2293
2294static ide_startstop_t idetape_media_access_finished (ide_drive_t *drive)
2295{
2296        idetape_tape_t *tape = drive->driver_data;
2297        idetape_pc_t *pc = tape->pc;
2298        atapi_status_t status;
2299
2300        status.all = HWIF(drive)->INB(IDE_STATUS_REG);
2301        if (status.b.dsc) {
2302                if (status.b.check) {
2303                        /* Error detected */
2304                        if (pc->c[0] != IDETAPE_TEST_UNIT_READY_CMD)
2305                                printk(KERN_ERR "ide-tape: %s: I/O error, ",
2306                                                tape->name);
2307                        /* Retry operation */
2308                        return idetape_retry_pc(drive);
2309                }
2310                pc->error = 0;
2311                if (tape->failed_pc == pc)
2312                        tape->failed_pc = NULL;
2313        } else {
2314                pc->error = IDETAPE_ERROR_GENERAL;
2315                tape->failed_pc = NULL;
2316        }
2317        return pc->callback(drive);
2318}
2319
2320static ide_startstop_t idetape_rw_callback (ide_drive_t *drive)
2321{
2322        idetape_tape_t *tape = drive->driver_data;
2323        struct request *rq = HWGROUP(drive)->rq;
2324        int blocks = tape->pc->actually_transferred / tape->tape_block_size;
2325
2326        tape->avg_size += blocks * tape->tape_block_size;
2327        tape->insert_size += blocks * tape->tape_block_size;
2328        if (tape->insert_size > 1024 * 1024)
2329                tape->measure_insert_time = 1;
2330        if (tape->measure_insert_time) {
2331                tape->measure_insert_time = 0;
2332                tape->insert_time = jiffies;
2333                tape->insert_size = 0;
2334        }
2335        if (time_after(jiffies, tape->insert_time))
2336                tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2337        if (time_after_eq(jiffies, tape->avg_time + HZ)) {
2338                tape->avg_speed = tape->avg_size * HZ / (jiffies - tape->avg_time) / 1024;
2339                tape->avg_size = 0;
2340                tape->avg_time = jiffies;
2341        }
2342
2343#if IDETAPE_DEBUG_LOG   
2344        if (tape->debug_level >= 4)
2345                printk(KERN_INFO "ide-tape: Reached idetape_rw_callback\n");
2346#endif /* IDETAPE_DEBUG_LOG */
2347
2348        tape->first_frame_position += blocks;
2349        rq->current_nr_sectors -= blocks;
2350
2351        if (!tape->pc->error)
2352                idetape_end_request(drive, 1, 0);
2353        else
2354                idetape_end_request(drive, tape->pc->error, 0);
2355        return ide_stopped;
2356}
2357
2358static void idetape_create_read_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2359{
2360        idetape_init_pc(pc);
2361        pc->c[0] = IDETAPE_READ_CMD;
2362        put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2363        pc->c[1] = 1;
2364        pc->callback = &idetape_rw_callback;
2365        pc->bh = bh;
2366        atomic_set(&bh->b_count, 0);
2367        pc->buffer = NULL;
2368        pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2369        if (pc->request_transfer == tape->stage_size)
2370                set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2371}
2372
2373static void idetape_create_read_buffer_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2374{
2375        int size = 32768;
2376        struct idetape_bh *p = bh;
2377
2378        idetape_init_pc(pc);
2379        pc->c[0] = IDETAPE_READ_BUFFER_CMD;
2380        pc->c[1] = IDETAPE_RETRIEVE_FAULTY_BLOCK;
2381        pc->c[7] = size >> 8;
2382        pc->c[8] = size & 0xff;
2383        pc->callback = &idetape_pc_callback;
2384        pc->bh = bh;
2385        atomic_set(&bh->b_count, 0);
2386        pc->buffer = NULL;
2387        while (p) {
2388                atomic_set(&p->b_count, 0);
2389                p = p->b_reqnext;
2390        }
2391        pc->request_transfer = pc->buffer_size = size;
2392}
2393
2394static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, unsigned int length, struct idetape_bh *bh)
2395{
2396        idetape_init_pc(pc);
2397        pc->c[0] = IDETAPE_WRITE_CMD;
2398        put_unaligned(htonl(length), (unsigned int *) &pc->c[1]);
2399        pc->c[1] = 1;
2400        pc->callback = &idetape_rw_callback;
2401        set_bit(PC_WRITING, &pc->flags);
2402        pc->bh = bh;
2403        pc->b_data = bh->b_data;
2404        pc->b_count = atomic_read(&bh->b_count);
2405        pc->buffer = NULL;
2406        pc->request_transfer = pc->buffer_size = length * tape->tape_block_size;
2407        if (pc->request_transfer == tape->stage_size)
2408                set_bit(PC_DMA_RECOMMENDED, &pc->flags);
2409}
2410
2411/*
2412 * idetape_do_request is our request handling function. 
2413 */
2414static ide_startstop_t idetape_do_request(ide_drive_t *drive,
2415                                          struct request *rq, sector_t block)
2416{
2417        idetape_tape_t *tape = drive->driver_data;
2418        idetape_pc_t *pc = NULL;
2419        struct request *postponed_rq = tape->postponed_rq;
2420        atapi_status_t status;
2421
2422#if IDETAPE_DEBUG_LOG
2423#if 0
2424        if (tape->debug_level >= 5)
2425                printk(KERN_INFO "ide-tape:  %d, "
2426                        "dev: %s, cmd: %ld, errors: %d\n",
2427                         rq->rq_disk->disk_name, rq->cmd[0], rq->errors);
2428#endif
2429        if (tape->debug_level >= 2)
2430                printk(KERN_INFO "ide-tape: sector: %ld, "
2431                        "nr_sectors: %ld, current_nr_sectors: %d\n",
2432                        rq->sector, rq->nr_sectors, rq->current_nr_sectors);
2433#endif /* IDETAPE_DEBUG_LOG */
2434
2435        if (!blk_special_request(rq)) {
2436                /*
2437                 * We do not support buffer cache originated requests.
2438                 */
2439                printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
2440                        "request queue (%d)\n", drive->name, rq->cmd_type);
2441                ide_end_request(drive, 0, 0);
2442                return ide_stopped;
2443        }
2444
2445        /*
2446         *      Retry a failed packet command
2447         */
2448        if (tape->failed_pc != NULL &&
2449            tape->pc->c[0] == IDETAPE_REQUEST_SENSE_CMD) {
2450                return idetape_issue_packet_command(drive, tape->failed_pc);
2451        }
2452#if IDETAPE_DEBUG_BUGS
2453        if (postponed_rq != NULL)
2454                if (rq != postponed_rq) {
2455                        printk(KERN_ERR "ide-tape: ide-tape.c bug - "
2456                                        "Two DSC requests were queued\n");
2457                        idetape_end_request(drive, 0, 0);
2458                        return ide_stopped;
2459                }
2460#endif /* IDETAPE_DEBUG_BUGS */
2461
2462        tape->postponed_rq = NULL;
2463
2464        /*
2465         * If the tape is still busy, postpone our request and service
2466         * the other device meanwhile.
2467         */
2468        status.all = HWIF(drive)->INB(IDE_STATUS_REG);
2469
2470        if (!drive->dsc_overlap && !(rq->cmd[0] & REQ_IDETAPE_PC2))
2471                set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2472
2473        if (drive->post_reset == 1) {
2474                set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
2475                drive->post_reset = 0;
2476        }
2477
2478        if (tape->tape_still_time > 100 && tape->tape_still_time < 200)
2479                tape->measure_insert_time = 1;
2480        if (time_after(jiffies, tape->insert_time))
2481                tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
2482        calculate_speeds(drive);
2483        if (!test_and_clear_bit(IDETAPE_IGNORE_DSC, &tape->flags) &&
2484            !status.b.dsc) {
2485                if (postponed_rq == NULL) {
2486                        tape->dsc_polling_start = jiffies;
2487                        tape->dsc_polling_frequency = tape->best_dsc_rw_frequency;
2488                        tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
2489                } else if (time_after(jiffies, tape->dsc_timeout)) {
2490                        printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
2491                                tape->name);
2492                        if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2493                                idetape_media_access_finished(drive);
2494                                return ide_stopped;
2495                        } else {
2496                                return ide_do_reset(drive);
2497                        }
2498                } else if (time_after(jiffies, tape->dsc_polling_start + IDETAPE_DSC_MA_THRESHOLD))
2499                        tape->dsc_polling_frequency = IDETAPE_DSC_MA_SLOW;
2500                idetape_postpone_request(drive);
2501                return ide_stopped;
2502        }
2503        if (rq->cmd[0] & REQ_IDETAPE_READ) {
2504                tape->buffer_head++;
2505#if USE_IOTRACE
2506                IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
2507#endif
2508                tape->postpone_cnt = 0;
2509                pc = idetape_next_pc_storage(drive);
2510                idetape_create_read_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2511                goto out;
2512        }
2513        if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
2514                tape->buffer_head++;
2515#if USE_IOTRACE
2516                IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
2517#endif
2518                tape->postpone_cnt = 0;
2519                pc = idetape_next_pc_storage(drive);
2520                idetape_create_write_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2521                goto out;
2522        }
2523        if (rq->cmd[0] & REQ_IDETAPE_READ_BUFFER) {
2524                tape->postpone_cnt = 0;
2525                pc = idetape_next_pc_storage(drive);
2526                idetape_create_read_buffer_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
2527                goto out;
2528        }
2529        if (rq->cmd[0] & REQ_IDETAPE_PC1) {
2530                pc = (idetape_pc_t *) rq->buffer;
2531                rq->cmd[0] &= ~(REQ_IDETAPE_PC1);
2532                rq->cmd[0] |= REQ_IDETAPE_PC2;
2533                goto out;
2534        }
2535        if (rq->cmd[0] & REQ_IDETAPE_PC2) {
2536                idetape_media_access_finished(drive);
2537                return ide_stopped;
2538        }
2539        BUG();
2540out:
2541        return idetape_issue_packet_command(drive, pc);
2542}
2543
2544/*
2545 *      Pipeline related functions
2546 */
2547static inline int idetape_pipeline_active (idetape_tape_t *tape)
2548{
2549        int rc1, rc2;
2550
2551        rc1 = test_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
2552        rc2 = (tape->active_data_request != NULL);
2553        return rc1;
2554}
2555
2556/*
2557 *      idetape_kmalloc_stage uses __get_free_page to allocate a pipeline
2558 *      stage, along with all the necessary small buffers which together make
2559 *      a buffer of size tape->stage_size (or a bit more). We attempt to
2560 *      combine sequential pages as much as possible.
2561 *
2562 *      Returns a pointer to the new allocated stage, or NULL if we
2563 *      can't (or don't want to) allocate a stage.
2564 *
2565 *      Pipeline stages are optional and are used to increase performance.
2566 *      If we can't allocate them, we'll manage without them.
2567 */
2568static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
2569{
2570        idetape_stage_t *stage;
2571        struct idetape_bh *prev_bh, *bh;
2572        int pages = tape->pages_per_stage;
2573        char *b_data = NULL;
2574
2575        if ((stage = kmalloc(sizeof (idetape_stage_t),GFP_KERNEL)) == NULL)
2576                return NULL;
2577        stage->next = NULL;
2578
2579        bh = stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
2580        if (bh == NULL)
2581                goto abort;
2582        bh->b_reqnext = NULL;
2583        if ((bh->b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2584                goto abort;
2585        if (clear)
2586                memset(bh->b_data, 0, PAGE_SIZE);
2587        bh->b_size = PAGE_SIZE;
2588        atomic_set(&bh->b_count, full ? bh->b_size : 0);
2589
2590        while (--pages) {
2591                if ((b_data = (char *) __get_free_page (GFP_KERNEL)) == NULL)
2592                        goto abort;
2593                if (clear)
2594                        memset(b_data, 0, PAGE_SIZE);
2595                if (bh->b_data == b_data + PAGE_SIZE) {
2596                        bh->b_size += PAGE_SIZE;
2597                        bh->b_data -= PAGE_SIZE;
2598                        if (full)
2599                                atomic_add(PAGE_SIZE, &bh->b_count);
2600                        continue;
2601                }
2602                if (b_data == bh->b_data + bh->b_size) {
2603                        bh->b_size += PAGE_SIZE;
2604                        if (full)
2605                                atomic_add(PAGE_SIZE, &bh->b_count);
2606                        continue;
2607                }
2608                prev_bh = bh;
2609                if ((bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL)) == NULL) {
2610                        free_page((unsigned long) b_data);
2611                        goto abort;
2612                }
2613                bh->b_reqnext = NULL;
2614                bh->b_data = b_data;
2615                bh->b_size = PAGE_SIZE;
2616                atomic_set(&bh->b_count, full ? bh->b_size : 0);
2617                prev_bh->b_reqnext = bh;
2618        }
2619        bh->b_size -= tape->excess_bh_size;
2620        if (full)
2621                atomic_sub(tape->excess_bh_size, &bh->b_count);
2622        return stage;
2623abort:
2624        __idetape_kfree_stage(stage);
2625        return NULL;
2626}
2627
2628static idetape_stage_t *idetape_kmalloc_stage (idetape_tape_t *tape)
2629{
2630        idetape_stage_t *cache_stage = tape->cache_stage;
2631
2632#if IDETAPE_DEBUG_LOG
2633        if (tape->debug_level >= 4)
2634                printk(KERN_INFO "ide-tape: Reached idetape_kmalloc_stage\n");
2635#endif /* IDETAPE_DEBUG_LOG */
2636
2637        if (tape->nr_stages >= tape->max_stages)
2638                return NULL;
2639        if (cache_stage != NULL) {
2640                tape->cache_stage = NULL;
2641                return cache_stage;
2642        }
2643        return __idetape_kmalloc_stage(tape, 0, 0);
2644}
2645
2646static int idetape_copy_stage_from_user (idetape_tape_t *tape, idetape_stage_t *stage, const char __user *buf, int n)
2647{
2648        struct idetape_bh *bh = tape->bh;
2649        int count;
2650        int ret = 0;
2651
2652        while (n) {
2653#if IDETAPE_DEBUG_BUGS
2654                if (bh == NULL) {
2655                        printk(KERN_ERR "ide-tape: bh == NULL in "
2656                                "idetape_copy_stage_from_user\n");
2657                        return 1;
2658                }
2659#endif /* IDETAPE_DEBUG_BUGS */
2660                count = min((unsigned int)(bh->b_size - atomic_read(&bh->b_count)), (unsigned int)n);
2661                if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf, count))
2662                        ret = 1;
2663                n -= count;
2664                atomic_add(count, &bh->b_count);
2665                buf += count;
2666                if (atomic_read(&bh->b_count) == bh->b_size) {
2667                        bh = bh->b_reqnext;
2668                        if (bh)
2669                                atomic_set(&bh->b_count, 0);
2670                }
2671        }
2672        tape->bh = bh;
2673        return ret;
2674}
2675
2676static int idetape_copy_stage_to_user (idetape_tape_t *tape, char __user *buf, idetape_stage_t *stage, int n)
2677{
2678        struct idetape_bh *bh = tape->bh;
2679        int count;
2680        int ret = 0;
2681
2682        while (n) {
2683#if IDETAPE_DEBUG_BUGS
2684                if (bh == NULL) {
2685                        printk(KERN_ERR "ide-tape: bh == NULL in "
2686                                "idetape_copy_stage_to_user\n");
2687                        return 1;
2688                }
2689#endif /* IDETAPE_DEBUG_BUGS */
2690                count = min(tape->b_count, n);
2691                if  (copy_to_user(buf, tape->b_data, count))
2692                        ret = 1;
2693                n -= count;
2694                tape->b_data += count;
2695                tape->b_count -= count;
2696                buf += count;
2697                if (!tape->b_count) {
2698                        tape->bh = bh = bh->b_reqnext;
2699                        if (bh) {
2700                                tape->b_data = bh->b_data;
2701                                tape->b_count = atomic_read(&bh->b_count);
2702                        }
2703                }
2704        }
2705        return ret;
2706}
2707
2708static void idetape_init_merge_stage (idetape_tape_t *tape)
2709{
2710        struct idetape_bh *bh = tape->merge_stage->bh;
2711        
2712        tape->bh = bh;
2713        if (tape->chrdev_direction == idetape_direction_write)
2714                atomic_set(&bh->b_count, 0);
2715        else {
2716                tape->b_data = bh->b_data;
2717                tape->b_count = atomic_read(&bh->b_count);
2718        }
2719}
2720
2721static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage)
2722{
2723        struct idetape_bh *tmp;
2724
2725        tmp = stage->bh;
2726        stage->bh = tape->merge_stage->bh;
2727        tape->merge_stage->bh = tmp;
2728        idetape_init_merge_stage(tape);
2729}
2730
2731/*
2732 *      idetape_add_stage_tail adds a new stage at the end of the pipeline.
2733 */
2734static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
2735{
2736        idetape_tape_t *tape = drive->driver_data;
2737        unsigned long flags;
2738        
2739#if IDETAPE_DEBUG_LOG
2740        if (tape->debug_level >= 4)
2741                printk (KERN_INFO "ide-tape: Reached idetape_add_stage_tail\n");
2742#endif /* IDETAPE_DEBUG_LOG */
2743        spin_lock_irqsave(&tape->spinlock, flags);
2744        stage->next = NULL;
2745        if (tape->last_stage != NULL)
2746                tape->last_stage->next=stage;
2747        else
2748                tape->first_stage = tape->next_stage=stage;
2749        tape->last_stage = stage;
2750        if (tape->next_stage == NULL)
2751                tape->next_stage = tape->last_stage;
2752        tape->nr_stages++;
2753        tape->nr_pending_stages++;
2754        spin_unlock_irqrestore(&tape->spinlock, flags);
2755}
2756
2757/*
2758 *      idetape_wait_for_request installs a completion in a pending request
2759 *      and sleeps until it is serviced.
2760 *
2761 *      The caller should ensure that the request will not be serviced
2762 *      before we install the completion (usually by disabling interrupts).
2763 */
2764static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
2765{
2766        DECLARE_COMPLETION_ONSTACK(wait);
2767        idetape_tape_t *tape = drive->driver_data;
2768
2769#if IDETAPE_DEBUG_BUGS
2770        if (rq == NULL || !blk_special_request(rq)) {
2771                printk (KERN_ERR "ide-tape: bug: Trying to sleep on non-valid request\n");
2772                return;
2773        }
2774#endif /* IDETAPE_DEBUG_BUGS */
2775        rq->end_io_data = &wait;
2776        rq->end_io = blk_end_sync_rq;
2777        spin_unlock_irq(&tape->spinlock);
2778        wait_for_completion(&wait);
2779        /* The stage and its struct request have been deallocated */
2780        spin_lock_irq(&tape->spinlock);
2781}
2782
2783static ide_startstop_t idetape_read_position_callback (ide_drive_t *drive)
2784{
2785        idetape_tape_t *tape = drive->driver_data;
2786        idetape_read_position_result_t *result;
2787        
2788#if IDETAPE_DEBUG_LOG
2789        if (tape->debug_level >= 4)
2790                printk(KERN_INFO "ide-tape: Reached idetape_read_position_callback\n");
2791#endif /* IDETAPE_DEBUG_LOG */
2792
2793        if (!tape->pc->error) {
2794                result = (idetape_read_position_result_t *) tape->pc->buffer;
2795#if IDETAPE_DEBUG_LOG
2796                if (tape->debug_level >= 2)
2797                        printk(KERN_INFO "ide-tape: BOP - %s\n",result->bop ? "Yes":"No");
2798                if (tape->debug_level >= 2)
2799                        printk(KERN_INFO "ide-tape: EOP - %s\n",result->eop ? "Yes":"No");
2800#endif /* IDETAPE_DEBUG_LOG */
2801                if (result->bpu) {
2802                        printk(KERN_INFO "ide-tape: Block location is unknown to the tape\n");
2803                        clear_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2804                        idetape_end_request(drive, 0, 0);
2805                } else {
2806#if IDETAPE_DEBUG_LOG
2807                        if (tape->debug_level >= 2)
2808                                printk(KERN_INFO "ide-tape: Block Location - %u\n", ntohl(result->first_block));
2809#endif /* IDETAPE_DEBUG_LOG */
2810                        tape->partition = result->partition;
2811                        tape->first_frame_position = ntohl(result->first_block);
2812                        tape->last_frame_position = ntohl(result->last_block);
2813                        tape->blocks_in_buffer = result->blocks_in_buffer[2];
2814                        set_bit(IDETAPE_ADDRESS_VALID, &tape->flags);
2815                        idetape_end_request(drive, 1, 0);
2816                }
2817        } else {
2818                idetape_end_request(drive, 0, 0);
2819        }
2820        return ide_stopped;
2821}
2822
2823/*
2824 *      idetape_create_write_filemark_cmd will:
2825 *
2826 *              1.      Write a filemark if write_filemark=1.
2827 *              2.      Flush the device buffers without writing a filemark
2828 *                      if write_filemark=0.
2829 *
2830 */
2831static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
2832{
2833        idetape_init_pc(pc);
2834        pc->c[0] = IDETAPE_WRITE_FILEMARK_CMD;
2835        pc->c[4] = write_filemark;
2836        set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2837        pc->callback = &idetape_pc_callback;
2838}
2839
2840static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
2841{
2842        idetape_init_pc(pc);
2843        pc->c[0] = IDETAPE_TEST_UNIT_READY_CMD;
2844        pc->callback = &idetape_pc_callback;
2845}
2846
2847/*
2848 *      idetape_queue_pc_tail is based on the following functions:
2849 *
2850 *      ide_do_drive_cmd from ide.c
2851 *      cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c
2852 *
2853 *      We add a special packet command request to the tail of the request
2854 *      queue, and wait for it to be serviced.
2855 *
2856 *      This is not to be called from within the request handling part
2857 *      of the driver ! We allocate here data in the stack, and it is valid
2858 *      until the request is finished. This is not the case for the bottom
2859 *      part of the driver, where we are always leaving the functions to wait
2860 *      for an interrupt or a timer event.
2861 *
2862 *      From the bottom part of the driver, we should allocate safe memory
2863 *      using idetape_next_pc_storage and idetape_next_rq_storage, and add
2864 *      the request to the request list without waiting for it to be serviced !
2865 *      In that case, we usually use idetape_queue_pc_head.
2866 */
2867static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
2868{
2869        struct ide_tape_obj *tape = drive->driver_data;
2870        struct request rq;
2871
2872        idetape_init_rq(&rq, REQ_IDETAPE_PC1);
2873        rq.buffer = (char *) pc;
2874        rq.rq_disk = tape->disk;
2875        return ide_do_drive_cmd(drive, &rq, ide_wait);
2876}
2877
2878static void idetape_create_load_unload_cmd (ide_drive_t *drive, idetape_pc_t *pc,int cmd)
2879{
2880        idetape_init_pc(pc);
2881        pc->c[0] = IDETAPE_LOAD_UNLOAD_CMD;
2882        pc->c[4] = cmd;
2883        set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2884        pc->callback = &idetape_pc_callback;
2885}
2886
2887static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
2888{
2889        idetape_tape_t *tape = drive->driver_data;
2890        idetape_pc_t pc;
2891        int load_attempted = 0;
2892
2893        /*
2894         * Wait for the tape to become ready
2895         */
2896        set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
2897        timeout += jiffies;
2898        while (time_before(jiffies, timeout)) {
2899                idetape_create_test_unit_ready_cmd(&pc);
2900                if (!__idetape_queue_pc_tail(drive, &pc))
2901                        return 0;
2902                if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
2903                    || (tape->asc == 0x3A)) {   /* no media */
2904                        if (load_attempted)
2905                                return -ENOMEDIUM;
2906                        idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
2907                        __idetape_queue_pc_tail(drive, &pc);
2908                        load_attempted = 1;
2909                /* not about to be ready */
2910                } else if (!(tape->sense_key == 2 && tape->asc == 4 &&
2911                             (tape->ascq == 1 || tape->ascq == 8)))
2912                        return -EIO;
2913                msleep(100);
2914        }
2915        return -EIO;
2916}
2917
2918static int idetape_queue_pc_tail (ide_drive_t *drive,idetape_pc_t *pc)
2919{
2920        return __idetape_queue_pc_tail(drive, pc);
2921}
2922
2923static int idetape_flush_tape_buffers (ide_drive_t *drive)
2924{
2925        idetape_pc_t pc;
2926        int rc;
2927
2928        idetape_create_write_filemark_cmd(drive, &pc, 0);
2929        if ((rc = idetape_queue_pc_tail(drive, &pc)))
2930                return rc;
2931        idetape_wait_ready(drive, 60 * 5 * HZ);
2932        return 0;
2933}
2934
2935static void idetape_create_read_position_cmd (idetape_pc_t *pc)
2936{
2937        idetape_init_pc(pc);
2938        pc->c[0] = IDETAPE_READ_POSITION_CMD;
2939        pc->request_transfer = 20;
2940        pc->callback = &idetape_read_position_callback;
2941}
2942
2943static int idetape_read_position (ide_drive_t *drive)
2944{
2945        idetape_tape_t *tape = drive->driver_data;
2946        idetape_pc_t pc;
2947        int position;
2948
2949#if IDETAPE_DEBUG_LOG
2950        if (tape->debug_level >= 4)
2951                printk(KERN_INFO "ide-tape: Reached idetape_read_position\n");
2952#endif /* IDETAPE_DEBUG_LOG */
2953
2954        idetape_create_read_position_cmd(&pc);
2955        if (idetape_queue_pc_tail(drive, &pc))
2956                return -1;
2957        position = tape->first_frame_position;
2958        return position;
2959}
2960
2961static void idetape_create_locate_cmd (ide_drive_t *drive, idetape_pc_t *pc, unsigned int block, u8 partition, int skip)
2962{
2963        idetape_init_pc(pc);
2964        pc->c[0] = IDETAPE_LOCATE_CMD;
2965        pc->c[1] = 2;
2966        put_unaligned(htonl(block), (unsigned int *) &pc->c[3]);
2967        pc->c[8] = partition;
2968        set_bit(PC_WAIT_FOR_DSC, &pc->flags);
2969        pc->callback = &idetape_pc_callback;
2970}
2971
2972static int idetape_create_prevent_cmd (ide_drive_t *drive, idetape_pc_t *pc, int prevent)
2973{
2974        idetape_tape_t *tape = drive->driver_data;
2975
2976        if (!tape->capabilities.lock)
2977                return 0;
2978
2979        idetape_init_pc(pc);
2980        pc->c[0] = IDETAPE_PREVENT_CMD;
2981        pc->c[4] = prevent;
2982        pc->callback = &idetape_pc_callback;
2983        return 1;
2984}
2985
2986static int __idetape_discard_read_pipeline (ide_drive_t *drive)
2987{
2988        idetape_tape_t *tape = drive->driver_data;
2989        unsigned long flags;
2990        int cnt;
2991
2992        if (tape->chrdev_direction != idetape_direction_read)
2993                return 0;
2994
2995        /* Remove merge stage. */
2996        cnt = tape->merge_stage_size / tape->tape_block_size;
2997        if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
2998                ++cnt;          /* Filemarks count as 1 sector */
2999        tape->merge_stage_size = 0;
3000        if (tape->merge_stage != NULL) {
3001                __idetape_kfree_stage(tape->merge_stage);
3002                tape->merge_stage = NULL;
3003        }
3004
3005        /* Clear pipeline flags. */
3006        clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
3007        tape->chrdev_direction = idetape_direction_none;
3008
3009        /* Remove pipeline stages. */
3010        if (tape->first_stage == NULL)
3011                return 0;
3012
3013        spin_lock_irqsave(&tape->spinlock, flags);
3014        tape->next_stage = NULL;
3015        if (idetape_pipeline_active(tape))
3016                idetape_wait_for_request(drive, tape->active_data_request);
3017        spin_unlock_irqrestore(&tape->spinlock, flags);
3018
3019        while (tape->first_stage != NULL) {
3020                struct request *rq_ptr = &tape->first_stage->rq;
3021
3022                cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors; 
3023                if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3024                        ++cnt;
3025                idetape_remove_stage_head(drive);
3026        }
3027        tape->nr_pending_stages = 0;
3028        tape->max_stages = tape->min_pipeline;
3029        return cnt;
3030}
3031
3032/*
3033 *      idetape_position_tape positions the tape to the requested block
3034 *      using the LOCATE packet command. A READ POSITION command is then
3035 *      issued to check where we are positioned.
3036 *
3037 *      Like all higher level operations, we queue the commands at the tail
3038 *      of the request queue and wait for their completion.
3039 *      
3040 */
3041static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
3042{
3043        idetape_tape_t *tape = drive->driver_data;
3044        int retval;
3045        idetape_pc_t pc;
3046
3047        if (tape->chrdev_direction == idetape_direction_read)
3048                __idetape_discard_read_pipeline(drive);
3049        idetape_wait_ready(drive, 60 * 5 * HZ);
3050        idetape_create_locate_cmd(drive, &pc, block, partition, skip);
3051        retval = idetape_queue_pc_tail(drive, &pc);
3052        if (retval)
3053                return (retval);
3054
3055        idetape_create_read_position_cmd(&pc);
3056        return (idetape_queue_pc_tail(drive, &pc));
3057}
3058
3059static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_position)
3060{
3061        idetape_tape_t *tape = drive->driver_data;
3062        int cnt;
3063        int seek, position;
3064
3065        cnt = __idetape_discard_read_pipeline(drive);
3066        if (restore_position) {
3067                position = idetape_read_position(drive);
3068                seek = position > cnt ? position - cnt : 0;
3069                if (idetape_position_tape(drive, seek, 0, 0)) {
3070                        printk(KERN_INFO "ide-tape: %s: position_tape failed in discard_pipeline()\n", tape->name);
3071                        return;
3072                }
3073        }
3074}
3075
3076/*
3077 * idetape_queue_rw_tail generates a read/write request for the block
3078 * device interface and wait for it to be serviced.
3079 */
3080static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
3081{
3082        idetape_tape_t *tape = drive->driver_data;
3083        struct request rq;
3084
3085#if IDETAPE_DEBUG_LOG
3086        if (tape->debug_level >= 2)
3087                printk(KERN_INFO "ide-tape: idetape_queue_rw_tail: cmd=%d\n",cmd);
3088#endif /* IDETAPE_DEBUG_LOG */
3089#if IDETAPE_DEBUG_BUGS
3090        if (idetape_pipeline_active(tape)) {
3091                printk(KERN_ERR "ide-tape: bug: the pipeline is active in idetape_queue_rw_tail\n");
3092                return (0);
3093        }
3094#endif /* IDETAPE_DEBUG_BUGS */ 
3095
3096        idetape_init_rq(&rq, cmd);
3097        rq.rq_disk = tape->disk;
3098        rq.special = (void *)bh;
3099        rq.sector = tape->first_frame_position;
3100        rq.nr_sectors = rq.current_nr_sectors = blocks;
3101        (void) ide_do_drive_cmd(drive, &rq, ide_wait);
3102
3103        if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
3104                return 0;
3105
3106        if (tape->merge_stage)
3107                idetape_init_merge_stage(tape);
3108        if (rq.errors == IDETAPE_ERROR_GENERAL)
3109                return -EIO;
3110        return (tape->tape_block_size * (blocks-rq.current_nr_sectors));
3111}
3112
3113/*
3114 *      idetape_insert_pipeline_into_queue is used to start servicing the
3115 *      pipeline stages, starting from tape->next_stage.
3116 */
3117static void idetape_insert_pipeline_into_queue (ide_drive_t *drive)
3118{
3119        idetape_tape_t *tape = drive->driver_data;
3120
3121        if (tape->next_stage == NULL)
3122                return;
3123        if (!idetape_pipeline_active(tape)) {
3124                set_bit(IDETAPE_PIPELINE_ACTIVE, &tape->flags);
3125                idetape_active_next_stage(drive);
3126                (void) ide_do_drive_cmd(drive, tape->active_data_request, ide_end);
3127        }
3128}
3129
3130static void idetape_create_inquiry_cmd (idetape_pc_t *pc)
3131{
3132        idetape_init_pc(pc);
3133        pc->c[0] = IDETAPE_INQUIRY_CMD;
3134        pc->c[4] = pc->request_transfer = 254;
3135        pc->callback = &idetape_pc_callback;
3136}
3137
3138static void idetape_create_rewind_cmd (ide_drive_t *drive, idetape_pc_t *pc)
3139{
3140        idetape_init_pc(pc);
3141        pc->c[0] = IDETAPE_REWIND_CMD;
3142        set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3143        pc->callback = &idetape_pc_callback;
3144}
3145
3146#if 0
3147static void idetape_create_mode_select_cmd (idetape_pc_t *pc, int length)
3148{
3149        idetape_init_pc(pc);
3150        set_bit(PC_WRITING, &pc->flags);
3151        pc->c[0] = IDETAPE_MODE_SELECT_CMD;
3152        pc->c[1] = 0x10;
3153        put_unaligned(htons(length), (unsigned short *) &pc->c[3]);
3154        pc->request_transfer = 255;
3155        pc->callback = &idetape_pc_callback;
3156}
3157#endif
3158
3159static void idetape_create_erase_cmd (idetape_pc_t *pc)
3160{
3161        idetape_init_pc(pc);
3162        pc->c[0] = IDETAPE_ERASE_CMD;
3163        pc->c[1] = 1;
3164        set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3165        pc->callback = &idetape_pc_callback;
3166}
3167
3168static void idetape_create_space_cmd (idetape_pc_t *pc,int count, u8 cmd)
3169{
3170        idetape_init_pc(pc);
3171        pc->c[0] = IDETAPE_SPACE_CMD;
3172        put_unaligned(htonl(count), (unsigned int *) &pc->c[1]);
3173        pc->c[1] = cmd;
3174        set_bit(PC_WAIT_FOR_DSC, &pc->flags);
3175        pc->callback = &idetape_pc_callback;
3176}
3177
3178static void idetape_wait_first_stage (ide_drive_t *drive)
3179{
3180        idetape_tape_t *tape = drive->driver_data;
3181        unsigned long flags;
3182
3183        if (tape->first_stage == NULL)
3184                return;
3185        spin_lock_irqsave(&tape->spinlock, flags);
3186        if (tape->active_stage == tape->first_stage)
3187                idetape_wait_for_request(drive, tape->active_data_request);
3188        spin_unlock_irqrestore(&tape->spinlock, flags);
3189}
3190
3191/*
3192 *      idetape_add_chrdev_write_request tries to add a character device
3193 *      originated write request to our pipeline. In case we don't succeed,
3194 *      we revert to non-pipelined operation mode for this request.
3195 *
3196 *      1.      Try to allocate a new pipeline stage.
3197 *      2.      If we can't, wait for more and more requests to be serviced
3198 *              and try again each time.
3199 *      3.      If we still can't allocate a stage, fallback to
3200 *              non-pipelined operation mode for this request.
3201 */
3202static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
3203{
3204        idetape_tape_t *tape = drive->driver_data;
3205        idetape_stage_t *new_stage;
3206        unsigned long flags;
3207        struct request *rq;
3208
3209#if IDETAPE_DEBUG_LOG
3210        if (tape->debug_level >= 3)
3211                printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_write_request\n");
3212#endif /* IDETAPE_DEBUG_LOG */
3213
3214        /*
3215         *      Attempt to allocate a new stage.
3216         *      Pay special attention to possible race conditions.
3217         */
3218        while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
3219                spin_lock_irqsave(&tape->spinlock, flags);
3220                if (idetape_pipeline_active(tape)) {
3221                        idetape_wait_for_request(drive, tape->active_data_request);
3222                        spin_unlock_irqrestore(&tape->spinlock, flags);
3223                } else {
3224                        spin_unlock_irqrestore(&tape->spinlock, flags);
3225                        idetape_insert_pipeline_into_queue(drive);
3226                        if (idetape_pipeline_active(tape))
3227                                continue;
3228                        /*
3229                         *      Linux is short on memory. Fallback to
3230                         *      non-pipelined operation mode for this request.
3231                         */
3232                        return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3233                }
3234        }
3235        rq = &new_stage->rq;
3236        idetape_init_rq(rq, REQ_IDETAPE_WRITE);
3237        /* Doesn't actually matter - We always assume sequential access */
3238        rq->sector = tape->first_frame_position;
3239        rq->nr_sectors = rq->current_nr_sectors = blocks;
3240
3241        idetape_switch_buffers(tape, new_stage);
3242        idetape_add_stage_tail(drive, new_stage);
3243        tape->pipeline_head++;
3244#if USE_IOTRACE
3245        IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
3246#endif
3247        calculate_speeds(drive);
3248
3249        /*
3250         *      Estimate whether the tape has stopped writing by checking
3251         *      if our write pipeline is currently empty. If we are not
3252         *      writing anymore, wait for the pipeline to be full enough
3253         *      (90%) before starting to service requests, so that we will
3254         *      be able to keep up with the higher speeds of the tape.
3255         */
3256        if (!idetape_pipeline_active(tape)) {
3257                if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
3258                    tape->nr_stages >= tape->max_stages - tape->uncontrolled_pipeline_head_speed * 3 * 1024 / tape->tape_block_size) {
3259                        tape->measure_insert_time = 1;
3260                        tape->insert_time = jiffies;
3261                        tape->insert_size = 0;
3262                        tape->insert_speed = 0;
3263                        idetape_insert_pipeline_into_queue(drive);
3264                }
3265        }
3266        if (test_and_clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3267                /* Return a deferred error */
3268                return -EIO;
3269        return blocks;
3270}
3271
3272/*
3273 *      idetape_wait_for_pipeline will wait until all pending pipeline
3274 *      requests are serviced. Typically called on device close.
3275 */
3276static void idetape_wait_for_pipeline (ide_drive_t *drive)
3277{
3278        idetape_tape_t *tape = drive->driver_data;
3279        unsigned long flags;
3280
3281        while (tape->next_stage || idetape_pipeline_active(tape)) {
3282                idetape_insert_pipeline_into_queue(drive);
3283                spin_lock_irqsave(&tape->spinlock, flags);
3284                if (idetape_pipeline_active(tape))
3285                        idetape_wait_for_request(drive, tape->active_data_request);
3286                spin_unlock_irqrestore(&tape->spinlock, flags);
3287        }
3288}
3289
3290static void idetape_empty_write_pipeline (ide_drive_t *drive)
3291{
3292        idetape_tape_t *tape = drive->driver_data;
3293        int blocks, min;
3294        struct idetape_bh *bh;
3295        
3296#if IDETAPE_DEBUG_BUGS
3297        if (tape->chrdev_direction != idetape_direction_write) {
3298                printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline, but we are not writing.\n");
3299                return;
3300        }
3301        if (tape->merge_stage_size > tape->stage_size) {
3302                printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
3303                tape->merge_stage_size = tape->stage_size;
3304        }
3305#endif /* IDETAPE_DEBUG_BUGS */
3306        if (tape->merge_stage_size) {
3307                blocks = tape->merge_stage_size / tape->tape_block_size;
3308                if (tape->merge_stage_size % tape->tape_block_size) {
3309                        unsigned int i;
3310
3311                        blocks++;
3312                        i = tape->tape_block_size - tape->merge_stage_size % tape->tape_block_size;
3313                        bh = tape->bh->b_reqnext;
3314                        while (bh) {
3315                                atomic_set(&bh->b_count, 0);
3316                                bh = bh->b_reqnext;
3317                        }
3318                        bh = tape->bh;
3319                        while (i) {
3320                                if (bh == NULL) {
3321
3322                                        printk(KERN_INFO "ide-tape: bug, bh NULL\n");
3323                                        break;
3324                                }
3325                                min = min(i, (unsigned int)(bh->b_size - atomic_read(&bh->b_count)));
3326                                memset(bh->b_data + atomic_read(&bh->b_count), 0, min);
3327                                atomic_add(min, &bh->b_count);
3328                                i -= min;
3329                                bh = bh->b_reqnext;
3330                        }
3331                }
3332                (void) idetape_add_chrdev_write_request(drive, blocks);
3333                tape->merge_stage_size = 0;
3334        }
3335        idetape_wait_for_pipeline(drive);
3336        if (tape->merge_stage != NULL) {
3337                __idetape_kfree_stage(tape->merge_stage);
3338                tape->merge_stage = NULL;
3339        }
3340        clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
3341        tape->chrdev_direction = idetape_direction_none;
3342
3343        /*
3344         *      On the next backup, perform the feedback loop again.
3345         *      (I don't want to keep sense information between backups,
3346         *       as some systems are constantly on, and the system load
3347         *       can be totally different on the next backup).
3348         */
3349        tape->max_stages = tape->min_pipeline;
3350#if IDETAPE_DEBUG_BUGS
3351        if (tape->first_stage != NULL ||
3352            tape->next_stage != NULL ||
3353            tape->last_stage != NULL ||
3354            tape->nr_stages != 0) {
3355                printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
3356                        "first_stage %p, next_stage %p, "
3357                        "last_stage %p, nr_stages %d\n",
3358                        tape->first_stage, tape->next_stage,
3359                        tape->last_stage, tape->nr_stages);
3360        }
3361#endif /* IDETAPE_DEBUG_BUGS */
3362}
3363
3364static void idetape_restart_speed_control (ide_drive_t *drive)
3365{
3366        idetape_tape_t *tape = drive->driver_data;
3367
3368        tape->restart_speed_control_req = 0;
3369        tape->pipeline_head = 0;
3370        tape->controlled_last_pipeline_head = tape->uncontrolled_last_pipeline_head = 0;
3371        tape->controlled_previous_pipeline_head = tape->uncontrolled_previous_pipeline_head = 0;
3372        tape->pipeline_head_speed = tape->controlled_pipeline_head_speed = 5000;
3373        tape->uncontrolled_pipeline_head_speed = 0;
3374        tape->controlled_pipeline_head_time = tape->uncontrolled_pipeline_head_time = jiffies;
3375        tape->controlled_previous_head_time = tape->uncontrolled_previous_head_time = jiffies;
3376}
3377
3378static int idetape_initiate_read (ide_drive_t *drive, int max_stages)
3379{
3380        idetape_tape_t *tape = drive->driver_data;
3381        idetape_stage_t *new_stage;
3382        struct request rq;
3383        int bytes_read;
3384        int blocks = tape->capabilities.ctl;
3385
3386        /* Initialize read operation */
3387        if (tape->chrdev_direction != idetape_direction_read) {
3388                if (tape->chrdev_direction == idetape_direction_write) {
3389                        idetape_empty_write_pipeline(drive);
3390                        idetape_flush_tape_buffers(drive);
3391                }
3392#if IDETAPE_DEBUG_BUGS
3393                if (tape->merge_stage || tape->merge_stage_size) {
3394                        printk (KERN_ERR "ide-tape: merge_stage_size should be 0 now\n");
3395                        tape->merge_stage_size = 0;
3396                }
3397#endif /* IDETAPE_DEBUG_BUGS */
3398                if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3399                        return -ENOMEM;
3400                tape->chrdev_direction = idetape_direction_read;
3401
3402                /*
3403                 *      Issue a read 0 command to ensure that DSC handshake
3404                 *      is switched from completion mode to buffer available
3405                 *      mode.
3406                 *      No point in issuing this if DSC overlap isn't supported,
3407                 *      some drives (Seagate STT3401A) will return an error.
3408                 */
3409                if (drive->dsc_overlap) {
3410                        bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
3411                        if (bytes_read < 0) {
3412                                __idetape_kfree_stage(tape->merge_stage);
3413                                tape->merge_stage = NULL;
3414                                tape->chrdev_direction = idetape_direction_none;
3415                                return bytes_read;
3416                        }
3417                }
3418        }
3419        if (tape->restart_speed_control_req)
3420                idetape_restart_speed_control(drive);
3421        idetape_init_rq(&rq, REQ_IDETAPE_READ);
3422        rq.sector = tape->first_frame_position;
3423        rq.nr_sectors = rq.current_nr_sectors = blocks;
3424        if (!test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags) &&
3425            tape->nr_stages < max_stages) {
3426                new_stage = idetape_kmalloc_stage(tape);
3427                while (new_stage != NULL) {
3428                        new_stage->rq = rq;
3429                        idetape_add_stage_tail(drive, new_stage);
3430                        if (tape->nr_stages >= max_stages)
3431                                break;
3432                        new_stage = idetape_kmalloc_stage(tape);
3433                }
3434        }
3435        if (!idetape_pipeline_active(tape)) {
3436                if (tape->nr_pending_stages >= 3 * max_stages / 4) {
3437                        tape->measure_insert_time = 1;
3438                        tape->insert_time = jiffies;
3439                        tape->insert_size = 0;
3440                        tape->insert_speed = 0;
3441                        idetape_insert_pipeline_into_queue(drive);
3442                }
3443        }
3444        return 0;
3445}
3446
3447/*
3448 *      idetape_add_chrdev_read_request is called from idetape_chrdev_read
3449 *      to service a character device read request and add read-ahead
3450 *      requests to our pipeline.
3451 */
3452static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
3453{
3454        idetape_tape_t *tape = drive->driver_data;
3455        unsigned long flags;
3456        struct request *rq_ptr;
3457        int bytes_read;
3458
3459#if IDETAPE_DEBUG_LOG
3460        if (tape->debug_level >= 4)
3461                printk(KERN_INFO "ide-tape: Reached idetape_add_chrdev_read_request, %d blocks\n", blocks);
3462#endif /* IDETAPE_DEBUG_LOG */
3463
3464        /*
3465         * If we are at a filemark, return a read length of 0
3466         */
3467        if (test_bit(IDETAPE_FILEMARK, &tape->flags))
3468                return 0;
3469
3470        /*
3471         * Wait for the next block to be available at the head
3472         * of the pipeline
3473         */
3474        idetape_initiate_read(drive, tape->max_stages);
3475        if (tape->first_stage == NULL) {
3476                if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
3477                        return 0;
3478                return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, tape->merge_stage->bh);
3479        }
3480        idetape_wait_first_stage(drive);
3481        rq_ptr = &tape->first_stage->rq;
3482        bytes_read = tape->tape_block_size * (rq_ptr->nr_sectors - rq_ptr->current_nr_sectors);
3483        rq_ptr->nr_sectors = rq_ptr->current_nr_sectors = 0;
3484
3485
3486        if (rq_ptr->errors == IDETAPE_ERROR_EOD)
3487                return 0;
3488        else {
3489                idetape_switch_buffers(tape, tape->first_stage);
3490                if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
3491                        set_bit(IDETAPE_FILEMARK, &tape->flags);
3492                spin_lock_irqsave(&tape->spinlock, flags);
3493                idetape_remove_stage_head(drive);
3494                spin_unlock_irqrestore(&tape->spinlock, flags);
3495                tape->pipeline_head++;
3496#if USE_IOTRACE
3497                IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
3498#endif
3499                calculate_speeds(drive);
3500        }
3501#if IDETAPE_DEBUG_BUGS
3502        if (bytes_read > blocks * tape->tape_block_size) {
3503                printk(KERN_ERR "ide-tape: bug: trying to return more bytes than requested\n");
3504                bytes_read = blocks * tape->tape_block_size;
3505        }
3506#endif /* IDETAPE_DEBUG_BUGS */
3507        return (bytes_read);
3508}
3509
3510static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
3511{
3512        idetape_tape_t *tape = drive->driver_data;
3513        struct idetape_bh *bh;
3514        int blocks;
3515        
3516        while (bcount) {
3517                unsigned int count;
3518
3519                bh = tape->merge_stage->bh;
3520                count = min(tape->stage_size, bcount);
3521                bcount -= count;
3522                blocks = count / tape->tape_block_size;
3523                while (count) {
3524                        atomic_set(&bh->b_count, min(count, (unsigned int)bh->b_size));
3525                        memset(bh->b_data, 0, atomic_read(&bh->b_count));
3526                        count -= atomic_read(&bh->b_count);
3527                        bh = bh->b_reqnext;
3528                }
3529                idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
3530        }
3531}
3532
3533static int idetape_pipeline_size (ide_drive_t *drive)
3534{
3535        idetape_tape_t *tape = drive->driver_data;
3536        idetape_stage_t *stage;
3537        struct request *rq;
3538        int size = 0;
3539
3540        idetape_wait_for_pipeline(drive);
3541        stage = tape->first_stage;
3542        while (stage != NULL) {
3543                rq = &stage->rq;
3544                size += tape->tape_block_size * (rq->nr_sectors-rq->current_nr_sectors);
3545                if (rq->errors == IDETAPE_ERROR_FILEMARK)
3546                        size += tape->tape_block_size;
3547                stage = stage->next;
3548        }
3549        size += tape->merge_stage_size;
3550        return size;
3551}
3552
3553/*
3554 *      Rewinds the tape to the Beginning Of the current Partition (BOP).
3555 *
3556 *      We currently support only one partition.
3557 */ 
3558static int idetape_rewind_tape (ide_drive_t *drive)
3559{
3560        int retval;
3561        idetape_pc_t pc;
3562#if IDETAPE_DEBUG_LOG
3563        idetape_tape_t *tape = drive->driver_data;
3564        if (tape->debug_level >= 2)
3565                printk(KERN_INFO "ide-tape: Reached idetape_rewind_tape\n");
3566#endif /* IDETAPE_DEBUG_LOG */  
3567        
3568        idetape_create_rewind_cmd(drive, &pc);
3569        retval = idetape_queue_pc_tail(drive, &pc);
3570        if (retval)
3571                return retval;
3572
3573        idetape_create_read_position_cmd(&pc);
3574        retval = idetape_queue_pc_tail(drive, &pc);
3575        if (retval)
3576                return retval;
3577        return 0;
3578}
3579
3580/*
3581 *      Our special ide-tape ioctl's.
3582 *
3583 *      Currently there aren't any ioctl's.
3584 *      mtio.h compatible commands should be issued to the character device
3585 *      interface.
3586 */
3587static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
3588{
3589        idetape_tape_t *tape = drive->driver_data;
3590        idetape_config_t config;
3591        void __user *argp = (void __user *)arg;
3592
3593#if IDETAPE_DEBUG_LOG   
3594        if (tape->debug_level >= 4)
3595                printk(KERN_INFO "ide-tape: Reached idetape_blkdev_ioctl\n");
3596#endif /* IDETAPE_DEBUG_LOG */
3597        switch (cmd) {
3598                case 0x0340:
3599                        if (copy_from_user(&config, argp, sizeof (idetape_config_t)))
3600                                return -EFAULT;
3601                        tape->best_dsc_rw_frequency = config.dsc_rw_frequency;
3602                        tape->max_stages = config.nr_stages;
3603                        break;
3604                case 0x0350:
3605                        config.dsc_rw_frequency = (int) tape->best_dsc_rw_frequency;
3606                        config.nr_stages = tape->max_stages; 
3607                        if (copy_to_user(argp, &config, sizeof (idetape_config_t)))
3608                                return -EFAULT;
3609                        break;
3610                default:
3611                        return -EIO;
3612        }
3613        return 0;
3614}
3615
3616/*
3617 *      idetape_space_over_filemarks is now a bit more complicated than just
3618 *      passing the command to the tape since we may have crossed some
3619 *      filemarks during our pipelined read-ahead mode.
3620 *
3621 *      As a minor side effect, the pipeline enables us to support MTFSFM when
3622 *      the filemark is in our internal pipeline even if the tape doesn't
3623 *      support spacing over filemarks in the reverse direction.
3624 */
3625static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
3626{
3627        idetape_tape_t *tape = drive->driver_data;
3628        idetape_pc_t pc;
3629        unsigned long flags;
3630        int retval,count=0;
3631
3632        if (mt_count == 0)
3633                return 0;
3634        if (MTBSF == mt_op || MTBSFM == mt_op) {
3635                if (!tape->capabilities.sprev)
3636                        return -EIO;
3637                mt_count = - mt_count;
3638        }
3639
3640        if (tape->chrdev_direction == idetape_direction_read) {
3641                /*
3642                 *      We have a read-ahead buffer. Scan it for crossed
3643                 *      filemarks.
3644                 */
3645                tape->merge_stage_size = 0;
3646                if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
3647                        ++count;
3648                while (tape->first_stage != NULL) {
3649                        if (count == mt_count) {
3650                                if (mt_op == MTFSFM)
3651                                        set_bit(IDETAPE_FILEMARK, &tape->flags);
3652                                return 0;
3653                        }
3654                        spin_lock_irqsave(&tape->spinlock, flags);
3655                        if (tape->first_stage == tape->active_stage) {
3656                                /*
3657                                 *      We have reached the active stage in the read pipeline.
3658                                 *      There is no point in allowing the drive to continue
3659                                 *      reading any farther, so we stop the pipeline.
3660                                 *
3661                                 *      This section should be moved to a separate subroutine,
3662                                 *      because a similar function is performed in
3663                                 *      __idetape_discard_read_pipeline(), for example.
3664                                 */
3665                                tape->next_stage = NULL;
3666                                spin_unlock_irqrestore(&tape->spinlock, flags);
3667                                idetape_wait_first_stage(drive);
3668                                tape->next_stage = tape->first_stage->next;
3669                        } else
3670                                spin_unlock_irqrestore(&tape->spinlock, flags);
3671                        if (tape->first_stage->rq.errors == IDETAPE_ERROR_FILEMARK)
3672                                ++count;
3673                        idetape_remove_stage_head(drive);
3674                }
3675                idetape_discard_read_pipeline(drive, 0);
3676        }
3677
3678        /*
3679         *      The filemark was not found in our internal pipeline.
3680         *      Now we can issue the space command.
3681         */
3682        switch (mt_op) {
3683                case MTFSF:
3684                case MTBSF:
3685                        idetape_create_space_cmd(&pc,mt_count-count,IDETAPE_SPACE_OVER_FILEMARK);
3686                        return (idetape_queue_pc_tail(drive, &pc));
3687                case MTFSFM:
3688                case MTBSFM:
3689                        if (!tape->capabilities.sprev)
3690                                return (-EIO);
3691                        retval = idetape_space_over_filemarks(drive, MTFSF, mt_count-count);
3692                        if (retval) return (retval);
3693                        count = (MTBSFM == mt_op ? 1 : -1);
3694                        return (idetape_space_over_filemarks(drive, MTFSF, count));
3695                default:
3696                        printk(KERN_ERR "ide-tape: MTIO operation %d not supported\n",mt_op);
3697                        return (-EIO);
3698        }
3699}
3700
3701
3702/*
3703 *      Our character device read / write functions.
3704 *
3705 *      The tape is optimized to maximize throughput when it is transferring
3706 *      an integral number of the "continuous transfer limit", which is
3707 *      a parameter of the specific tape (26 KB on my particular tape).
3708 *      (32 kB for Onstream)
3709 *
3710 *      As of version 1.3 of the driver, the character device provides an
3711 *      abstract continuous view of the media - any mix of block sizes (even 1
3712 *      byte) on the same backup/restore procedure is supported. The driver
3713 *      will internally convert the requests to the recommended transfer unit,
3714 *      so that an unmatch between the user's block size to the recommended
3715 *      size will only result in a (slightly) increased driver overhead, but
3716 *      will no longer hit performance.
3717 *      This is not applicable to Onstream.
3718 */
3719static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
3720                                    size_t count, loff_t *ppos)
3721{
3722        struct ide_tape_obj *tape = ide_tape_f(file);
3723        ide_drive_t *drive = tape->drive;
3724        ssize_t bytes_read,temp, actually_read = 0, rc;
3725        ssize_t ret = 0;
3726
3727#if IDETAPE_DEBUG_LOG
3728        if (tape->debug_level >= 3)
3729                printk(KERN_INFO "ide-tape: Reached idetape_chrdev_read, count %Zd\n", count);
3730#endif /* IDETAPE_DEBUG_LOG */
3731
3732        if (tape->chrdev_direction != idetape_direction_read) {
3733                if (test_bit(IDETAPE_DETECT_BS, &tape->flags))
3734                        if (count > tape->tape_block_size &&
3735                            (count % tape->tape_block_size) == 0)
3736                                tape->user_bs_factor = count / tape->tape_block_size;
3737        }
3738        if ((rc = idetape_initiate_read(drive, tape->max_stages)) < 0)
3739                return rc;
3740        if (count == 0)
3741                return (0);
3742        if (tape->merge_stage_size) {
3743                actually_read = min((unsigned int)(tape->merge_stage_size), (unsigned int)count);
3744                if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, actually_read))
3745                        ret = -EFAULT;
3746                buf += actually_read;
3747                tape->merge_stage_size -= actually_read;
3748                count -= actually_read;
3749        }
3750        while (count >= tape->stage_size) {
3751                bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3752                if (bytes_read <= 0)
3753                        goto finish;
3754                if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, bytes_read))
3755                        ret = -EFAULT;
3756                buf += bytes_read;
3757                count -= bytes_read;
3758                actually_read += bytes_read;
3759        }
3760        if (count) {
3761                bytes_read = idetape_add_chrdev_read_request(drive, tape->capabilities.ctl);
3762                if (bytes_read <= 0)
3763                        goto finish;
3764                temp = min((unsigned long)count, (unsigned long)bytes_read);
3765                if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage, temp))
3766                        ret = -EFAULT;
3767                actually_read += temp;
3768                tape->merge_stage_size = bytes_read-temp;
3769        }
3770finish:
3771        if (!actually_read && test_bit(IDETAPE_FILEMARK, &tape->flags)) {
3772#if IDETAPE_DEBUG_LOG
3773                if (tape->debug_level >= 2)
3774                        printk(KERN_INFO "ide-tape: %s: spacing over filemark\n", tape->name);
3775#endif
3776                idetape_space_over_filemarks(drive, MTFSF, 1);
3777                return 0;
3778        }
3779
3780        return (ret) ? ret : actually_read;
3781}
3782
3783static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
3784                                     size_t count, loff_t *ppos)
3785{
3786        struct ide_tape_obj *tape = ide_tape_f(file);
3787        ide_drive_t *drive = tape->drive;
3788        ssize_t actually_written = 0;
3789        ssize_t ret = 0;
3790
3791        /* The drive is write protected. */
3792        if (tape->write_prot)
3793                return -EACCES;
3794
3795#if IDETAPE_DEBUG_LOG
3796        if (tape->debug_level >= 3)
3797                printk(KERN_INFO "ide-tape: Reached idetape_chrdev_write, "
3798                        "count %Zd\n", count);
3799#endif /* IDETAPE_DEBUG_LOG */
3800
3801        /* Initialize write operation */
3802        if (tape->chrdev_direction != idetape_direction_write) {
3803                if (tape->chrdev_direction == idetape_direction_read)
3804                        idetape_discard_read_pipeline(drive, 1);
3805#if IDETAPE_DEBUG_BUGS
3806                if (tape->merge_stage || tape->merge_stage_size) {
3807                        printk(KERN_ERR "ide-tape: merge_stage_size "
3808                                "should be 0 now\n");
3809                        tape->merge_stage_size = 0;
3810                }
3811#endif /* IDETAPE_DEBUG_BUGS */
3812                if ((tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0)) == NULL)
3813                        return -ENOMEM;
3814                tape->chrdev_direction = idetape_direction_write;
3815                idetape_init_merge_stage(tape);
3816
3817                /*
3818                 *      Issue a write 0 command to ensure that DSC handshake
3819                 *      is switched from completion mode to buffer available
3820                 *      mode.
3821                 *      No point in issuing this if DSC overlap isn't supported,
3822                 *      some drives (Seagate STT3401A) will return an error.
3823                 */
3824                if (drive->dsc_overlap) {
3825                        ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
3826                        if (retval < 0) {
3827                                __idetape_kfree_stage(tape->merge_stage);
3828                                tape->merge_stage = NULL;
3829                                tape->chrdev_direction = idetape_direction_none;
3830                                return retval;
3831                        }
3832                }
3833        }
3834        if (count == 0)
3835                return (0);
3836        if (tape->restart_speed_control_req)
3837                idetape_restart_speed_control(drive);
3838        if (tape->merge_stage_size) {
3839#if IDETAPE_DEBUG_BUGS
3840                if (tape->merge_stage_size >= tape->stage_size) {
3841                        printk(KERN_ERR "ide-tape: bug: merge buffer too big\n");
3842                        tape->merge_stage_size = 0;
3843                }
3844#endif /* IDETAPE_DEBUG_BUGS */
3845                actually_written = min((unsigned int)(tape->stage_size - tape->merge_stage_size), (unsigned int)count);
3846                if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, actually_written))
3847                                ret = -EFAULT;
3848                buf += actually_written;
3849                tape->merge_stage_size += actually_written;
3850                count -= actually_written;
3851
3852                if (tape->merge_stage_size == tape->stage_size) {
3853                        ssize_t retval;
3854                        tape->merge_stage_size = 0;
3855                        retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3856                        if (retval <= 0)
3857                                return (retval);
3858                }
3859        }
3860        while (count >= tape->stage_size) {
3861                ssize_t retval;
3862                if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, tape->stage_size))
3863                        ret = -EFAULT;
3864                buf += tape->stage_size;
3865                count -= tape->stage_size;
3866                retval = idetape_add_chrdev_write_request(drive, tape->capabilities.ctl);
3867                actually_written += tape->stage_size;
3868                if (retval <= 0)
3869                        return (retval);
3870        }
3871        if (count) {
3872                actually_written += count;
3873                if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf, count))
3874                        ret = -EFAULT;
3875                tape->merge_stage_size += count;
3876        }
3877        return (ret) ? ret : actually_written;
3878}
3879
3880static int idetape_write_filemark (ide_drive_t *drive)
3881{
3882        idetape_pc_t pc;
3883
3884        /* Write a filemark */
3885        idetape_create_write_filemark_cmd(drive, &pc, 1);
3886        if (idetape_queue_pc_tail(drive, &pc)) {
3887                printk(KERN_ERR "ide-tape: Couldn't write a filemark\n");
3888                return -EIO;
3889        }
3890        return 0;
3891}
3892
3893/*
3894 *      idetape_mtioctop is called from idetape_chrdev_ioctl when
3895 *      the general mtio MTIOCTOP ioctl is requested.
3896 *
3897 *      We currently support the following mtio.h operations:
3898 *
3899 *      MTFSF   -       Space over mt_count filemarks in the positive direction.
3900 *                      The tape is positioned after the last spaced filemark.
3901 *
3902 *      MTFSFM  -       Same as MTFSF, but the tape is positioned before the
3903 *                      last filemark.
3904 *
3905 *      MTBSF   -       Steps background over mt_count filemarks, tape is
3906 *                      positioned before the last filemark.
3907 *
3908 *      MTBSFM  -       Like MTBSF, only tape is positioned after the last filemark.
3909 *
3910 *      Note:
3911 *
3912 *              MTBSF and MTBSFM are not supported when the tape doesn't
3913 *              support spacing over filemarks in the reverse direction.
3914 *              In this case, MTFSFM is also usually not supported (it is
3915 *              supported in the rare case in which we crossed the filemark
3916 *              during our read-ahead pipelined operation mode).
3917 *              
3918 *      MTWEOF  -       Writes mt_count filemarks. Tape is positioned after
3919 *                      the last written filemark.
3920 *
3921 *      MTREW   -       Rewinds tape.
3922 *
3923 *      MTLOAD  -       Loads the tape.
3924 *
3925 *      MTOFFL  -       Puts the tape drive "Offline": Rewinds the tape and
3926 *      MTUNLOAD        prevents further access until the media is replaced.
3927 *
3928 *      MTNOP   -       Flushes tape buffers.
3929 *
3930 *      MTRETEN -       Retension media. This typically consists of one end
3931 *                      to end pass on the media.
3932 *
3933 *      MTEOM   -       Moves to the end of recorded data.
3934 *
3935 *      MTERASE -       Erases tape.
3936 *
3937 *      MTSETBLK -      Sets the user block size to mt_count bytes. If
3938 *                      mt_count is 0, we will attempt to autodetect
3939 *                      the block size.
3940 *
3941 *      MTSEEK  -       Positions the tape in a specific block number, where
3942 *                      each block is assumed to contain which user_block_size
3943 *                      bytes.
3944 *
3945 *      MTSETPART -     Switches to another tape partition.
3946 *
3947 *      MTLOCK -        Locks the tape door.
3948 *
3949 *      MTUNLOCK -      Unlocks the tape door.
3950 *
3951 *      The following commands are currently not supported:
3952 *
3953 *      MTFSS, MTBSS, MTWSM, MTSETDENSITY,
3954 *      MTSETDRVBUFFER, MT_ST_BOOLEANS, MT_ST_WRITE_THRESHOLD.
3955 */
3956static int idetape_mtioctop (ide_drive_t *drive,short mt_op,int mt_count)
3957{
3958        idetape_tape_t *tape = drive->driver_data;
3959        idetape_pc_t pc;
3960        int i,retval;
3961
3962#if IDETAPE_DEBUG_LOG
3963        if (tape->debug_level >= 1)
3964                printk(KERN_INFO "ide-tape: Handling MTIOCTOP ioctl: "
3965                        "mt_op=%d, mt_count=%d\n", mt_op, mt_count);
3966#endif /* IDETAPE_DEBUG_LOG */
3967        /*
3968         *      Commands which need our pipelined read-ahead stages.
3969         */
3970        switch (mt_op) {
3971                case MTFSF:
3972                case MTFSFM:
3973                case MTBSF:
3974                case MTBSFM:
3975                        if (!mt_count)
3976                                return (0);
3977                        return (idetape_space_over_filemarks(drive,mt_op,mt_count));
3978                default:
3979                        break;
3980        }
3981        switch (mt_op) {
3982                case MTWEOF:
3983                        if (tape->write_prot)
3984                                return -EACCES;
3985                        idetape_discard_read_pipeline(drive, 1);
3986                        for (i = 0; i < mt_count; i++) {
3987                                retval = idetape_write_filemark(drive);
3988                                if (retval)
3989                                        return retval;
3990                        }
3991                        return (0);
3992                case MTREW:
3993                        idetape_discard_read_pipeline(drive, 0);
3994                        if (idetape_rewind_tape(drive))
3995                                return -EIO;
3996                        return 0;
3997                case MTLOAD:
3998                        idetape_discard_read_pipeline(drive, 0);
3999                        idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
4000                        return (idetape_queue_pc_tail(drive, &pc));
4001                case MTUNLOAD:
4002                case MTOFFL:
4003                        /*
4004                         * If door is locked, attempt to unlock before
4005                         * attempting to eject.
4006                         */
4007                        if (tape->door_locked) {
4008                                if (idetape_create_prevent_cmd(drive, &pc, 0))
4009                                        if (!idetape_queue_pc_tail(drive, &pc))
4010                                                tape->door_locked = DOOR_UNLOCKED;
4011                        }
4012                        idetape_discard_read_pipeline(drive, 0);
4013                        idetape_create_load_unload_cmd(drive, &pc,!IDETAPE_LU_LOAD_MASK);
4014                        retval = idetape_queue_pc_tail(drive, &pc);
4015                        if (!retval)
4016                                clear_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
4017                        return retval;
4018                case MTNOP:
4019                        idetape_discard_read_pipeline(drive, 0);
4020                        return (idetape_flush_tape_buffers(drive));
4021                case MTRETEN:
4022                        idetape_discard_read_pipeline(drive, 0);
4023                        idetape_create_load_unload_cmd(drive, &pc,IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
4024                        return (idetape_queue_pc_tail(drive, &pc));
4025                case MTEOM:
4026                        idetape_create_space_cmd(&pc, 0, IDETAPE_SPACE_TO_EOD);
4027                        return (idetape_queue_pc_tail(drive, &pc));
4028                case MTERASE:
4029                        (void) idetape_rewind_tape(drive);
4030                        idetape_create_erase_cmd(&pc);
4031                        return (idetape_queue_pc_tail(drive, &pc));
4032                case MTSETBLK:
4033                        if (mt_count) {
4034                                if (mt_count < tape->tape_block_size || mt_count % tape->tape_block_size)
4035                                        return -EIO;
4036                                tape->user_bs_factor = mt_count / tape->tape_block_size;
4037                                clear_bit(IDETAPE_DETECT_BS, &tape->flags);
4038                        } else
4039                                set_bit(IDETAPE_DETECT_BS, &tape->flags);
4040                        return 0;
4041                case MTSEEK:
4042                        idetape_discard_read_pipeline(drive, 0);
4043                        return idetape_position_tape(drive, mt_count * tape->user_bs_factor, tape->partition, 0);
4044                case MTSETPART:
4045                        idetape_discard_read_pipeline(drive, 0);
4046                        return (idetape_position_tape(drive, 0, mt_count, 0));
4047                case MTFSR:
4048                case MTBSR:
4049                case MTLOCK:
4050                        if (!idetape_create_prevent_cmd(drive, &pc, 1))
4051                                return 0;
4052                        retval = idetape_queue_pc_tail(drive, &pc);
4053                        if (retval) return retval;
4054                        tape->door_locked = DOOR_EXPLICITLY_LOCKED;
4055                        return 0;
4056                case MTUNLOCK:
4057                        if (!idetape_create_prevent_cmd(drive, &pc, 0))
4058                                return 0;
4059                        retval = idetape_queue_pc_tail(drive, &pc);
4060                        if (retval) return retval;
4061                        tape->door_locked = DOOR_UNLOCKED;
4062                        return 0;
4063                default:
4064                        printk(KERN_ERR "ide-tape: MTIO operation %d not "
4065                                "supported\n", mt_op);
4066                        return (-EIO);
4067        }
4068}
4069
4070/*
4071 *      Our character device ioctls.
4072 *
4073 *      General mtio.h magnetic io commands are supported here, and not in
4074 *      the corresponding block interface.
4075 *
4076 *      The following ioctls are supported:
4077 *
4078 *      MTIOCTOP -      Refer to idetape_mtioctop for detailed description.
4079 *
4080 *      MTIOCGET -      The mt_dsreg field in the returned mtget structure
4081 *                      will be set to (user block size in bytes <<
4082 *                      MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK.
4083 *
4084 *                      The mt_blkno is set to the current user block number.
4085 *                      The other mtget fields are not supported.
4086 *
4087 *      MTIOCPOS -      The current tape "block position" is returned. We
4088 *                      assume that each block contains user_block_size
4089 *                      bytes.
4090 *
4091 *      Our own ide-tape ioctls are supported on both interfaces.
4092 */
4093static int idetape_chrdev_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
4094{
4095        struct ide_tape_obj *tape = ide_tape_f(file);
4096        ide_drive_t *drive = tape->drive;
4097        struct mtop mtop;
4098        struct mtget mtget;
4099        struct mtpos mtpos;
4100        int block_offset = 0, position = tape->first_frame_position;
4101        void __user *argp = (void __user *)arg;
4102
4103#if IDETAPE_DEBUG_LOG
4104        if (tape->debug_level >= 3)
4105                printk(KERN_INFO "ide-tape: Reached idetape_chrdev_ioctl, "
4106                        "cmd=%u\n", cmd);
4107#endif /* IDETAPE_DEBUG_LOG */
4108
4109        tape->restart_speed_control_req = 1;
4110        if (tape->chrdev_direction == idetape_direction_write) {
4111                idetape_empty_write_pipeline(drive);
4112                idetape_flush_tape_buffers(drive);
4113        }
4114        if (cmd == MTIOCGET || cmd == MTIOCPOS) {
4115                block_offset = idetape_pipeline_size(drive) / (tape->tape_block_size * tape->user_bs_factor);
4116                if ((position = idetape_read_position(drive)) < 0)
4117                        return -EIO;
4118        }
4119        switch (cmd) {
4120                case MTIOCTOP:
4121                        if (copy_from_user(&mtop, argp, sizeof (struct mtop)))
4122                                return -EFAULT;
4123                        return (idetape_mtioctop(drive,mtop.mt_op,mtop.mt_count));
4124                case MTIOCGET:
4125                        memset(&mtget, 0, sizeof (struct mtget));
4126                        mtget.mt_type = MT_ISSCSI2;
4127                        mtget.mt_blkno = position / tape->user_bs_factor - block_offset;
4128                        mtget.mt_dsreg = ((tape->tape_block_size * tape->user_bs_factor) << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK;
4129                        if (tape->drv_write_prot) {
4130                                mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
4131                        }
4132                        if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
4133                                return -EFAULT;
4134                        return 0;
4135                case MTIOCPOS:
4136                        mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
4137                        if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
4138                                return -EFAULT;
4139                        return 0;
4140                default:
4141                        if (tape->chrdev_direction == idetape_direction_read)
4142                                idetape_discard_read_pipeline(drive, 1);
4143                        return idetape_blkdev_ioctl(drive, cmd, arg);
4144        }
4145}
4146
4147static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive);
4148
4149/*
4150 *      Our character device open function.
4151 */
4152static int idetape_chrdev_open (struct inode *inode, struct file *filp)
4153{
4154        unsigned int minor = iminor(inode), i = minor & ~0xc0;
4155        ide_drive_t *drive;
4156        idetape_tape_t *tape;
4157        idetape_pc_t pc;
4158        int retval;
4159
4160        /*
4161         * We really want to do nonseekable_open(inode, filp); here, but some
4162         * versions of tar incorrectly call lseek on tapes and bail out if that
4163         * fails.  So we disallow pread() and pwrite(), but permit lseeks.
4164         */
4165        filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
4166
4167#if IDETAPE_DEBUG_LOG
4168        printk(KERN_INFO "ide-tape: Reached idetape_chrdev_open\n");
4169#endif /* IDETAPE_DEBUG_LOG */
4170        
4171        if (i >= MAX_HWIFS * MAX_DRIVES)
4172                return -ENXIO;
4173
4174        if (!(tape = ide_tape_chrdev_get(i)))
4175                return -ENXIO;
4176
4177        drive = tape->drive;
4178
4179        filp->private_data = tape;
4180
4181        if (test_and_set_bit(IDETAPE_BUSY, &tape->flags)) {
4182                retval = -EBUSY;
4183                goto out_put_tape;
4184        }
4185
4186        retval = idetape_wait_ready(drive, 60 * HZ);
4187        if (retval) {
4188                clear_bit(IDETAPE_BUSY, &tape->flags);
4189                printk(KERN_ERR "ide-tape: %s: drive not ready\n", tape->name);
4190                goto out_put_tape;
4191        }
4192
4193        idetape_read_position(drive);
4194        if (!test_bit(IDETAPE_ADDRESS_VALID, &tape->flags))
4195                (void)idetape_rewind_tape(drive);
4196
4197        if (tape->chrdev_direction != idetape_direction_read)
4198                clear_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
4199
4200        /* Read block size and write protect status from drive. */
4201        idetape_get_blocksize_from_block_descriptor(drive);
4202
4203        /* Set write protect flag if device is opened as read-only. */
4204        if ((filp->f_flags & O_ACCMODE) == O_RDONLY)
4205                tape->write_prot = 1;
4206        else
4207                tape->write_prot = tape->drv_write_prot;
4208
4209        /* Make sure drive isn't write protected if user wants to write. */
4210        if (tape->write_prot) {
4211                if ((filp->f_flags & O_ACCMODE) == O_WRONLY ||
4212                    (filp->f_flags & O_ACCMODE) == O_RDWR) {
4213                        clear_bit(IDETAPE_BUSY, &tape->flags);
4214                        retval = -EROFS;
4215                        goto out_put_tape;
4216                }
4217        }
4218
4219        /*
4220         * Lock the tape drive door so user can't eject.
4221         */
4222        if (tape->chrdev_direction == idetape_direction_none) {
4223                if (idetape_create_prevent_cmd(drive, &pc, 1)) {
4224                        if (!idetape_queue_pc_tail(drive, &pc)) {
4225                                if (tape->door_locked != DOOR_EXPLICITLY_LOCKED)
4226                                        tape->door_locked = DOOR_LOCKED;
4227                        }
4228                }
4229        }
4230        idetape_restart_speed_control(drive);
4231        tape->restart_speed_control_req = 0;
4232        return 0;
4233
4234out_put_tape:
4235        ide_tape_put(tape);
4236        return retval;
4237}
4238
4239static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
4240{
4241        idetape_tape_t *tape = drive->driver_data;
4242
4243        idetape_empty_write_pipeline(drive);
4244        tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
4245        if (tape->merge_stage != NULL) {
4246                idetape_pad_zeros(drive, tape->tape_block_size * (tape->user_bs_factor - 1));
4247                __idetape_kfree_stage(tape->merge_stage);
4248                tape->merge_stage = NULL;
4249        }
4250        idetape_write_filemark(drive);
4251        idetape_flush_tape_buffers(drive);
4252        idetape_flush_tape_buffers(drive);
4253}
4254
4255/*
4256 *      Our character device release function.
4257 */
4258static int idetape_chrdev_release (struct inode *inode, struct file *filp)
4259{
4260        struct ide_tape_obj *tape = ide_tape_f(filp);
4261        ide_drive_t *drive = tape->drive;
4262        idetape_pc_t pc;
4263        unsigned int minor = iminor(inode);
4264
4265        lock_kernel();
4266        tape = drive->driver_data;
4267#if IDETAPE_DEBUG_LOG
4268        if (tape->debug_level >= 3)
4269                printk(KERN_INFO "ide-tape: Reached idetape_chrdev_release\n");
4270#endif /* IDETAPE_DEBUG_LOG */
4271
4272        if (tape->chrdev_direction == idetape_direction_write)
4273                idetape_write_release(drive, minor);
4274        if (tape->chrdev_direction == idetape_direction_read) {
4275                if (minor < 128)
4276                        idetape_discard_read_pipeline(drive, 1);
4277                else
4278                        idetape_wait_for_pipeline(drive);
4279        }
4280        if (tape->cache_stage != NULL) {
4281                __idetape_kfree_stage(tape->cache_stage);
4282                tape->cache_stage = NULL;
4283        }
4284        if (minor < 128 && test_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags))
4285                (void) idetape_rewind_tape(drive);
4286        if (tape->chrdev_direction == idetape_direction_none) {
4287                if (tape->door_locked == DOOR_LOCKED) {
4288                        if (idetape_create_prevent_cmd(drive, &pc, 0)) {
4289                                if (!idetape_queue_pc_tail(drive, &pc))
4290                                        tape->door_locked = DOOR_UNLOCKED;
4291                        }
4292                }
4293        }
4294        clear_bit(IDETAPE_BUSY, &tape->flags);
4295        ide_tape_put(tape);
4296        unlock_kernel();
4297        return 0;
4298}
4299
4300/*
4301 *      idetape_identify_device is called to check the contents of the
4302 *      ATAPI IDENTIFY command results. We return:
4303 *
4304 *      1       If the tape can be supported by us, based on the information
4305 *              we have so far.
4306 *
4307 *      0       If this tape driver is not currently supported by us.
4308 */
4309static int idetape_identify_device (ide_drive_t *drive)
4310{
4311        struct idetape_id_gcw gcw;
4312        struct hd_driveid *id = drive->id;
4313#if IDETAPE_DEBUG_INFO
4314        unsigned short mask,i;
4315#endif /* IDETAPE_DEBUG_INFO */
4316
4317        if (drive->id_read == 0)
4318                return 1;
4319
4320        *((unsigned short *) &gcw) = id->config;
4321
4322#if IDETAPE_DEBUG_INFO
4323        printk(KERN_INFO "ide-tape: Dumping ATAPI Identify Device tape parameters\n");
4324        printk(KERN_INFO "ide-tape: Protocol Type: ");
4325        switch (gcw.protocol) {
4326                case 0: case 1: printk("ATA\n");break;
4327                case 2: printk("ATAPI\n");break;
4328                case 3: printk("Reserved (Unknown to ide-tape)\n");break;
4329        }
4330        printk(KERN_INFO "ide-tape: Device Type: %x - ",gcw.device_type);       
4331        switch (gcw.device_type) {
4332                case 0: printk("Direct-access Device\n");break;
4333                case 1: printk("Streaming Tape Device\n");break;
4334                case 2: case 3: case 4: printk("Reserved\n");break;
4335                case 5: printk("CD-ROM Device\n");break;
4336                case 6: printk("Reserved\n");
4337                case 7: printk("Optical memory Device\n");break;
4338                case 0x1f: printk("Unknown or no Device type\n");break;
4339                default: printk("Reserved\n");
4340        }
4341        printk(KERN_INFO "ide-tape: Removable: %s",gcw.removable ? "Yes\n":"No\n");     
4342        printk(KERN_INFO "ide-tape: Command Packet DRQ Type: ");
4343        switch (gcw.drq_type) {
4344                case 0: printk("Microprocessor DRQ\n");break;
4345                case 1: printk("Interrupt DRQ\n");break;
4346                case 2: printk("Accelerated DRQ\n");break;
4347                case 3: printk("Reserved\n");break;
4348        }
4349        printk(KERN_INFO "ide-tape: Command Packet Size: ");
4350        switch (gcw.packet_size) {
4351                case 0: printk("12 bytes\n");break;
4352                case 1: printk("16 bytes\n");break;
4353                default: printk("Reserved\n");break;
4354        }
4355        printk(KERN_INFO "ide-tape: Model: %.40s\n",id->model);
4356        printk(KERN_INFO "ide-tape: Firmware Revision: %.8s\n",id->fw_rev);
4357        printk(KERN_INFO "ide-tape: Serial Number: %.20s\n",id->serial_no);
4358        printk(KERN_INFO "ide-tape: Write buffer size: %d bytes\n",id->buf_size*512);
4359        printk(KERN_INFO "ide-tape: DMA: %s",id->capability & 0x01 ? "Yes\n":"No\n");
4360        printk(KERN_INFO "ide-tape: LBA: %s",id->capability & 0x02 ? "Yes\n":"No\n");
4361        printk(KERN_INFO "ide-tape: IORDY can be disabled: %s",id->capability & 0x04 ? "Yes\n":"No\n");
4362        printk(KERN_INFO "ide-tape: IORDY supported: %s",id->capability & 0x08 ? "Yes\n":"Unknown\n");
4363        printk(KERN_INFO "ide-tape: ATAPI overlap supported: %s",id->capability & 0x20 ? "Yes\n":"No\n");
4364        printk(KERN_INFO "ide-tape: PIO Cycle Timing Category: %d\n",id->tPIO);
4365        printk(KERN_INFO "ide-tape: DMA Cycle Timing Category: %d\n",id->tDMA);
4366        printk(KERN_INFO "ide-tape: Single Word DMA supported modes: ");
4367        for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4368                if (id->dma_1word & mask)
4369                        printk("%d ",i);
4370                if (id->dma_1word & (mask << 8))
4371                        printk("(active) ");
4372        }
4373        printk("\n");
4374        printk(KERN_INFO "ide-tape: Multi Word DMA supported modes: ");
4375        for (i=0,mask=1;i<8;i++,mask=mask << 1) {
4376                if (id->dma_mword & mask)
4377                        printk("%d ",i);
4378                if (id->dma_mword & (mask << 8))
4379                        printk("(active) ");
4380        }
4381        printk("\n");
4382        if (id->field_valid & 0x0002) {
4383                printk(KERN_INFO "ide-tape: Enhanced PIO Modes: %s\n",
4384                        id->eide_pio_modes & 1 ? "Mode 3":"None");
4385                printk(KERN_INFO "ide-tape: Minimum Multi-word DMA cycle per word: ");
4386                if (id->eide_dma_min == 0)
4387                        printk("Not supported\n");
4388                else
4389                        printk("%d ns\n",id->eide_dma_min);
4390
4391                printk(KERN_INFO "ide-tape: Manufacturer\'s Recommended Multi-word cycle: ");
4392                if (id->eide_dma_time == 0)
4393                        printk("Not supported\n");
4394                else
4395                        printk("%d ns\n",id->eide_dma_time);
4396
4397                printk(KERN_INFO "ide-tape: Minimum PIO cycle without IORDY: ");
4398                if (id->eide_pio == 0)
4399                        printk("Not supported\n");
4400                else
4401                        printk("%d ns\n",id->eide_pio);
4402
4403                printk(KERN_INFO "ide-tape: Minimum PIO cycle with IORDY: ");
4404                if (id->eide_pio_iordy == 0)
4405                        printk("Not supported\n");
4406                else
4407                        printk("%d ns\n",id->eide_pio_iordy);
4408                
4409        } else
4410                printk(KERN_INFO "ide-tape: According to the device, fields 64-70 are not valid.\n");
4411#endif /* IDETAPE_DEBUG_INFO */
4412
4413        /* Check that we can support this device */
4414
4415        if (gcw.protocol !=2 )
4416                printk(KERN_ERR "ide-tape: Protocol is not ATAPI\n");
4417        else if (gcw.device_type != 1)
4418                printk(KERN_ERR "ide-tape: Device type is not set to tape\n");
4419        else if (!gcw.removable)
4420                printk(KERN_ERR "ide-tape: The removable flag is not set\n");
4421        else if (gcw.packet_size != 0) {
4422                printk(KERN_ERR "ide-tape: Packet size is not 12 bytes long\n");
4423                if (gcw.packet_size == 1)
4424                        printk(KERN_ERR "ide-tape: Sorry, padding to 16 bytes is still not supported\n");
4425        } else
4426                return 1;
4427        return 0;
4428}
4429
4430/*
4431 * Use INQUIRY to get the firmware revision
4432 */
4433static void idetape_get_inquiry_results (ide_drive_t *drive)
4434{
4435        char *r;
4436        idetape_tape_t *tape = drive->driver_data;
4437        idetape_pc_t pc;
4438        idetape_inquiry_result_t *inquiry;
4439        
4440        idetape_create_inquiry_cmd(&pc);
4441        if (idetape_queue_pc_tail(drive, &pc)) {
4442                printk(KERN_ERR "ide-tape: %s: can't get INQUIRY results\n", tape->name);
4443                return;
4444        }
4445        inquiry = (idetape_inquiry_result_t *) pc.buffer;
4446        memcpy(tape->vendor_id, inquiry->vendor_id, 8);
4447        memcpy(tape->product_id, inquiry->product_id, 16);
4448        memcpy(tape->firmware_revision, inquiry->revision_level, 4);
4449        ide_fixstring(tape->vendor_id, 10, 0);
4450        ide_fixstring(tape->product_id, 18, 0);
4451        ide_fixstring(tape->firmware_revision, 6, 0);
4452        r = tape->firmware_revision;
4453        if (*(r + 1) == '.')
4454                tape->firmware_revision_num = (*r - '0') * 100 + (*(r + 2) - '0') * 10 + *(r + 3) - '0';
4455        printk(KERN_INFO "ide-tape: %s <-> %s: %s %s rev %s\n", drive->name, tape->name, tape->vendor_id, tape->product_id, tape->firmware_revision);
4456}
4457
4458/*
4459 *      idetape_get_mode_sense_results asks the tape about its various
4460 *      parameters. In particular, we will adjust our data transfer buffer
4461 *      size to the recommended value as returned by the tape.
4462 */
4463static void idetape_get_mode_sense_results (ide_drive_t *drive)
4464{
4465        idetape_tape_t *tape = drive->driver_data;
4466        idetape_pc_t pc;
4467        idetape_mode_parameter_header_t *header;
4468        idetape_capabilities_page_t *capabilities;
4469        
4470        idetape_create_mode_sense_cmd(&pc, IDETAPE_CAPABILITIES_PAGE);
4471        if (idetape_queue_pc_tail(drive, &pc)) {
4472                printk(KERN_ERR "ide-tape: Can't get tape parameters - assuming some default values\n");
4473                tape->tape_block_size = 512;
4474                tape->capabilities.ctl = 52;
4475                tape->capabilities.speed = 450;
4476                tape->capabilities.buffer_size = 6 * 52;
4477                return;
4478        }
4479        header = (idetape_mode_parameter_header_t *) pc.buffer;
4480        capabilities = (idetape_capabilities_page_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t) + header->bdl);
4481
4482        capabilities->max_speed = ntohs(capabilities->max_speed);
4483        capabilities->ctl = ntohs(capabilities->ctl);
4484        capabilities->speed = ntohs(capabilities->speed);
4485        capabilities->buffer_size = ntohs(capabilities->buffer_size);
4486
4487        if (!capabilities->speed) {
4488                printk(KERN_INFO "ide-tape: %s: overriding capabilities->speed (assuming 650KB/sec)\n", drive->name);
4489                capabilities->speed = 650;
4490        }
4491        if (!capabilities->max_speed) {
4492                printk(KERN_INFO "ide-tape: %s: overriding capabilities->max_speed (assuming 650KB/sec)\n", drive->name);
4493                capabilities->max_speed = 650;
4494        }
4495
4496        tape->capabilities = *capabilities;             /* Save us a copy */
4497        if (capabilities->blk512)
4498                tape->tape_block_size = 512;
4499        else if (capabilities->blk1024)
4500                tape->tape_block_size = 1024;
4501
4502#if IDETAPE_DEBUG_INFO
4503        printk(KERN_INFO "ide-tape: Dumping the results of the MODE SENSE packet command\n");
4504        printk(KERN_INFO "ide-tape: Mode Parameter Header:\n");
4505        printk(KERN_INFO "ide-tape: Mode Data Length - %d\n",header->mode_data_length);
4506        printk(KERN_INFO "ide-tape: Medium Type - %d\n",header->medium_type);
4507        printk(KERN_INFO "ide-tape: Device Specific Parameter - %d\n",header->dsp);
4508        printk(KERN_INFO "ide-tape: Block Descriptor Length - %d\n",header->bdl);
4509        
4510        printk(KERN_INFO "ide-tape: Capabilities and Mechanical Status Page:\n");
4511        printk(KERN_INFO "ide-tape: Page code - %d\n",capabilities->page_code);
4512        printk(KERN_INFO "ide-tape: Page length - %d\n",capabilities->page_length);
4513        printk(KERN_INFO "ide-tape: Read only - %s\n",capabilities->ro ? "Yes":"No");
4514        printk(KERN_INFO "ide-tape: Supports reverse space - %s\n",capabilities->sprev ? "Yes":"No");
4515        printk(KERN_INFO "ide-tape: Supports erase initiated formatting - %s\n",capabilities->efmt ? "Yes":"No");
4516        printk(KERN_INFO "ide-tape: Supports QFA two Partition format - %s\n",capabilities->qfa ? "Yes":"No");
4517        printk(KERN_INFO "ide-tape: Supports locking the medium - %s\n",capabilities->lock ? "Yes":"No");
4518        printk(KERN_INFO "ide-tape: The volume is currently locked - %s\n",capabilities->locked ? "Yes":"No");
4519        printk(KERN_INFO "ide-tape: The device defaults in the prevent state - %s\n",capabilities->prevent ? "Yes":"No");
4520        printk(KERN_INFO "ide-tape: Supports ejecting the medium - %s\n",capabilities->eject ? "Yes":"No");
4521        printk(KERN_INFO "ide-tape: Supports error correction - %s\n",capabilities->ecc ? "Yes":"No");
4522        printk(KERN_INFO "ide-tape: Supports data compression - %s\n",capabilities->cmprs ? "Yes":"No");
4523        printk(KERN_INFO "ide-tape: Supports 512 bytes block size - %s\n",capabilities->blk512 ? "Yes":"No");
4524        printk(KERN_INFO "ide-tape: Supports 1024 bytes block size - %s\n",capabilities->blk1024 ? "Yes":"No");
4525        printk(KERN_INFO "ide-tape: Supports 32768 bytes block size / Restricted byte count for PIO transfers - %s\n",capabilities->blk32768 ? "Yes":"No");
4526        printk(KERN_INFO "ide-tape: Maximum supported speed in KBps - %d\n",capabilities->max_speed);
4527        printk(KERN_INFO "ide-tape: Continuous transfer limits in blocks - %d\n",capabilities->ctl);
4528        printk(KERN_INFO "ide-tape: Current speed in KBps - %d\n",capabilities->speed); 
4529        printk(KERN_INFO "ide-tape: Buffer size - %d\n",capabilities->buffer_size*512);
4530#endif /* IDETAPE_DEBUG_INFO */
4531}
4532
4533/*
4534 *      ide_get_blocksize_from_block_descriptor does a mode sense page 0 with block descriptor
4535 *      and if it succeeds sets the tape block size with the reported value
4536 */
4537static void idetape_get_blocksize_from_block_descriptor(ide_drive_t *drive)
4538{
4539
4540        idetape_tape_t *tape = drive->driver_data;
4541        idetape_pc_t pc;
4542        idetape_mode_parameter_header_t *header;
4543        idetape_parameter_block_descriptor_t *block_descrp;
4544        
4545        idetape_create_mode_sense_cmd(&pc, IDETAPE_BLOCK_DESCRIPTOR);
4546        if (idetape_queue_pc_tail(drive, &pc)) {
4547                printk(KERN_ERR "ide-tape: Can't get block descriptor\n");
4548                if (tape->tape_block_size == 0) {
4549                        printk(KERN_WARNING "ide-tape: Cannot deal with zero block size, assume 32k\n");
4550                        tape->tape_block_size =  32768;
4551                }
4552                return;
4553        }
4554        header = (idetape_mode_parameter_header_t *) pc.buffer;
4555        block_descrp = (idetape_parameter_block_descriptor_t *) (pc.buffer + sizeof(idetape_mode_parameter_header_t));
4556        tape->tape_block_size =( block_descrp->length[0]<<16) + (block_descrp->length[1]<<8) + block_descrp->length[2];
4557        tape->drv_write_prot = (header->dsp & 0x80) >> 7;
4558
4559#if IDETAPE_DEBUG_INFO
4560        printk(KERN_INFO "ide-tape: Adjusted block size - %d\n", tape->tape_block_size);
4561#endif /* IDETAPE_DEBUG_INFO */
4562}
4563
4564#ifdef CONFIG_IDE_PROC_FS
4565static void idetape_add_settings (ide_drive_t *drive)
4566{
4567        idetape_tape_t *tape = drive->driver_data;
4568
4569/*
4570 *                      drive   setting name            read/write      data type       min                     max                     mul_factor                      div_factor      data pointer                            set function
4571 */
4572        ide_add_setting(drive,  "buffer",               SETTING_READ,   TYPE_SHORT,     0,                      0xffff,                 1,                              2,              &tape->capabilities.buffer_size,        NULL);
4573        ide_add_setting(drive,  "pipeline_min",         SETTING_RW,     TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->min_pipeline,                    NULL);
4574        ide_add_setting(drive,  "pipeline",             SETTING_RW,     TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->max_stages,                      NULL);
4575        ide_add_setting(drive,  "pipeline_max",         SETTING_RW,     TYPE_INT,       1,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->max_pipeline,                    NULL);
4576        ide_add_setting(drive,  "pipeline_used",        SETTING_READ,   TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->nr_stages,                       NULL);
4577        ide_add_setting(drive,  "pipeline_pending",     SETTING_READ,   TYPE_INT,       0,                      0xffff,                 tape->stage_size / 1024,        1,              &tape->nr_pending_stages,               NULL);
4578        ide_add_setting(drive,  "speed",                SETTING_READ,   TYPE_SHORT,     0,                      0xffff,                 1,                              1,              &tape->capabilities.speed,              NULL);
4579        ide_add_setting(drive,  "stage",                SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1024,           &tape->stage_size,                      NULL);
4580        ide_add_setting(drive,  "tdsc",                 SETTING_RW,     TYPE_INT,       IDETAPE_DSC_RW_MIN,     IDETAPE_DSC_RW_MAX,     1000,                           HZ,             &tape->best_dsc_rw_frequency,           NULL);
4581        ide_add_setting(drive,  "dsc_overlap",          SETTING_RW,     TYPE_BYTE,      0,                      1,                      1,                              1,              &drive->dsc_overlap,                    NULL);
4582        ide_add_setting(drive,  "pipeline_head_speed_c",SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->controlled_pipeline_head_speed,  NULL);
4583        ide_add_setting(drive,  "pipeline_head_speed_u",SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->uncontrolled_pipeline_head_speed,NULL);
4584        ide_add_setting(drive,  "avg_speed",            SETTING_READ,   TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->avg_speed,                       NULL);
4585        ide_add_setting(drive,  "debug_level",          SETTING_RW,     TYPE_INT,       0,                      0xffff,                 1,                              1,              &tape->debug_level,                     NULL);
4586}
4587#else
4588static inline void idetape_add_settings(ide_drive_t *drive) { ; }
4589#endif
4590
4591/*
4592 *      ide_setup is called to:
4593 *
4594 *              1.      Initialize our various state variables.
4595 *              2.      Ask the tape for its capabilities.
4596 *              3.      Allocate a buffer which will be used for data
4597 *                      transfer. The buffer size is chosen based on
4598 *                      the recommendation which we received in step (2).
4599 *
4600 *      Note that at this point ide.c already assigned us an irq, so that
4601 *      we can queue requests here and wait for their completion.
4602 */
4603static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
4604{
4605        unsigned long t1, tmid, tn, t;
4606        int speed;
4607        struct idetape_id_gcw gcw;
4608        int stage_size;
4609        struct sysinfo si;
4610
4611        spin_lock_init(&tape->spinlock);
4612        drive->dsc_overlap = 1;
4613#ifdef CONFIG_BLK_DEV_IDEPCI
4614        if (HWIF(drive)->pci_dev != NULL) {
4615                /*
4616                 * These two ide-pci host adapters appear to need DSC overlap disabled.
4617                 * This probably needs further analysis.
4618                 */
4619                if ((HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_ARTOP_ATP850UF) ||
4620                    (HWIF(drive)->pci_dev->device == PCI_DEVICE_ID_TTI_HPT343)) {
4621                        printk(KERN_INFO "ide-tape: %s: disabling DSC overlap\n", tape->name);
4622                        drive->dsc_overlap = 0;
4623                }
4624        }
4625#endif /* CONFIG_BLK_DEV_IDEPCI */
4626        /* Seagate Travan drives do not support DSC overlap. */
4627        if (strstr(drive->id->model, "Seagate STT3401"))
4628                drive->dsc_overlap = 0;
4629        tape->minor = minor;
4630        tape->name[0] = 'h';
4631        tape->name[1] = 't';
4632        tape->name[2] = '0' + minor;
4633        tape->chrdev_direction = idetape_direction_none;
4634        tape->pc = tape->pc_stack;
4635        tape->max_insert_speed = 10000;
4636        tape->speed_control = 1;
4637        *((unsigned short *) &gcw) = drive->id->config;
4638        if (gcw.drq_type == 1)
4639                set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);
4640
4641        tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
4642        
4643        idetape_get_inquiry_results(drive);
4644        idetape_get_mode_sense_results(drive);
4645        idetape_get_blocksize_from_block_descriptor(drive);
4646        tape->user_bs_factor = 1;
4647        tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4648        while (tape->stage_size > 0xffff) {
4649                printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
4650                tape->capabilities.ctl /= 2;
4651                tape->stage_size = tape->capabilities.ctl * tape->tape_block_size;
4652        }
4653        stage_size = tape->stage_size;
4654        tape->pages_per_stage = stage_size / PAGE_SIZE;
4655        if (stage_size % PAGE_SIZE) {
4656                tape->pages_per_stage++;
4657                tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
4658        }
4659
4660        /*
4661         *      Select the "best" DSC read/write polling frequency
4662         *      and pipeline size.
4663         */
4664        speed = max(tape->capabilities.speed, tape->capabilities.max_speed);
4665
4666        tape->max_stages = speed * 1000 * 10 / tape->stage_size;
4667
4668        /*
4669         *      Limit memory use for pipeline to 10% of physical memory
4670         */
4671        si_meminfo(&si);
4672        if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10)
4673                tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size);
4674        tape->max_stages   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
4675        tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
4676        tape->max_pipeline = min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
4677        if (tape->max_stages == 0)
4678                tape->max_stages = tape->min_pipeline = tape->max_pipeline = 1;
4679
4680        t1 = (tape->stage_size * HZ) / (speed * 1000);
4681        tmid = (tape->capabilities.buffer_size * 32 * HZ) / (speed * 125);
4682        tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);
4683
4684        if (tape->max_stages)
4685                t = tn;
4686        else
4687                t = t1;
4688
4689        /*
4690         *      Ensure that the number we got makes sense; limit
4691         *      it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
4692         */
4693        tape->best_dsc_rw_frequency = max_t(unsigned long, min_t(unsigned long, t, IDETAPE_DSC_RW_MAX), IDETAPE_DSC_RW_MIN);
4694        printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
4695                "%dkB pipeline, %lums tDSC%s\n",
4696                drive->name, tape->name, tape->capabilities.speed,
4697                (tape->capabilities.buffer_size * 512) / tape->stage_size,
4698                tape->stage_size / 1024,
4699                tape->max_stages * tape->stage_size / 1024,
4700                tape->best_dsc_rw_frequency * 1000 / HZ,
4701                drive->using_dma ? ", DMA":"");
4702
4703        idetape_add_settings(drive);
4704}
4705
4706static void ide_tape_remove(ide_drive_t *drive)
4707{
4708        idetape_tape_t *tape = drive->driver_data;
4709
4710        ide_proc_unregister_driver(drive, tape->driver);
4711
4712        ide_unregister_region(tape->disk);
4713
4714        ide_tape_put(tape);
4715}
4716
4717static void ide_tape_release(struct kref *kref)
4718{
4719        struct ide_tape_obj *tape = to_ide_tape(kref);
4720        ide_drive_t *drive = tape->drive;
4721        struct gendisk *g = tape->disk;
4722
4723        BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);
4724
4725        drive->dsc_overlap = 0;
4726        drive->driver_data = NULL;
4727        class_device_destroy(idetape_sysfs_class,
4728                        MKDEV(IDETAPE_MAJOR, tape->minor));
4729        class_device_destroy(idetape_sysfs_class,
4730                        MKDEV(IDETAPE_MAJOR, tape->minor + 128));
4731        idetape_devs[tape->minor] = NULL;
4732        g->private_data = NULL;
4733        put_disk(g);
4734        kfree(tape);
4735}
4736
4737#ifdef CONFIG_IDE_PROC_FS
4738static int proc_idetape_read_name
4739        (char *page, char **start, off_t off, int count, int *eof, void *data)
4740{
4741        ide_drive_t     *drive = (ide_drive_t *) data;
4742        idetape_tape_t  *tape = drive->driver_data;
4743        char            *out = page;
4744        int             len;
4745
4746        len = sprintf(out, "%s\n", tape->name);
4747        PROC_IDE_READ_RETURN(page, start, off, count, eof, len);
4748}
4749
4750static ide_proc_entry_t idetape_proc[] = {
4751        { "capacity",   S_IFREG|S_IRUGO,        proc_ide_read_capacity, NULL },
4752        { "name",       S_IFREG|S_IRUGO,        proc_idetape_read_name, NULL },
4753        { NULL, 0, NULL, NULL }
4754};
4755#endif
4756
4757static int ide_tape_probe(ide_drive_t *);
4758
4759static ide_driver_t idetape_driver = {
4760        .gen_driver = {
4761                .owner          = THIS_MODULE,
4762                .name           = "ide-tape",
4763                .bus            = &ide_bus_type,
4764        },
4765        .probe                  = ide_tape_probe,
4766        .remove                 = ide_tape_remove,
4767        .version                = IDETAPE_VERSION,
4768        .media                  = ide_tape,
4769        .supports_dsc_overlap   = 1,
4770        .do_request             = idetape_do_request,
4771        .end_request            = idetape_end_request,
4772        .error                  = __ide_error,
4773        .abort                  = __ide_abort,
4774#ifdef CONFIG_IDE_PROC_FS
4775        .proc                   = idetape_proc,
4776#endif
4777};
4778
4779/*
4780 *      Our character device supporting functions, passed to register_chrdev.
4781 */
4782static const struct file_operations idetape_fops = {
4783        .owner          = THIS_MODULE,
4784        .read           = idetape_chrdev_read,
4785        .write          = idetape_chrdev_write,
4786        .ioctl          = idetape_chrdev_ioctl,
4787        .open           = idetape_chrdev_open,
4788        .release        = idetape_chrdev_release,
4789};
4790
4791static int idetape_open(struct inode *inode, struct file *filp)
4792{
4793        struct gendisk *disk = inode->i_bdev->bd_disk;
4794        struct ide_tape_obj *tape;
4795
4796        if (!(tape = ide_tape_get(disk)))
4797                return -ENXIO;
4798
4799        return 0;
4800}
4801
4802static int idetape_release(struct inode *inode, struct file *filp)
4803{
4804        struct gendisk *disk = inode->i_bdev->bd_disk;
4805        struct ide_tape_obj *tape = ide_tape_g(disk);
4806
4807        ide_tape_put(tape);
4808
4809        return 0;
4810}
4811
4812static int idetape_ioctl(struct inode *inode, struct file *file,
4813                        unsigned int cmd, unsigned long arg)
4814{
4815        struct block_device *bdev = inode->i_bdev;
4816        struct ide_tape_obj *tape = ide_tape_g(bdev->bd_disk);
4817        ide_drive_t *drive = tape->drive;
4818        int err = generic_ide_ioctl(drive, file, bdev, cmd, arg);
4819        if (err == -EINVAL)
4820                err = idetape_blkdev_ioctl(drive, cmd, arg);
4821        return err;
4822}
4823
4824static struct block_device_operations idetape_block_ops = {
4825        .owner          = THIS_MODULE,
4826        .open           = idetape_open,
4827        .release        = idetape_release,
4828        .ioctl          = idetape_ioctl,
4829};
4830
4831static int ide_tape_probe(ide_drive_t *drive)
4832{
4833        idetape_tape_t *tape;
4834        struct gendisk *g;
4835        int minor;
4836
4837        if (!strstr("ide-tape", drive->driver_req))
4838                goto failed;
4839        if (!drive->present)
4840                goto failed;
4841        if (drive->media != ide_tape)
4842                goto failed;
4843        if (!idetape_identify_device (drive)) {
4844                printk(KERN_ERR "ide-tape: %s: not supported by this version of ide-tape\n", drive->name);
4845                goto failed;
4846        }
4847        if (drive->scsi) {
4848                printk("ide-tape: passing drive %s to ide-scsi emulation.\n", drive->name);
4849                goto failed;
4850        }
4851        if (strstr(drive->id->model, "OnStream DI-")) {
4852                printk(KERN_WARNING "ide-tape: Use drive %s with ide-scsi emulation and osst.\n", drive->name);
4853                printk(KERN_WARNING "ide-tape: OnStream support will be removed soon from ide-tape!\n");
4854        }
4855        tape = kzalloc(sizeof (idetape_tape_t), GFP_KERNEL);
4856        if (tape == NULL) {
4857                printk(KERN_ERR "ide-tape: %s: Can't allocate a tape structure\n", drive->name);
4858                goto failed;
4859        }
4860
4861        g = alloc_disk(1 << PARTN_BITS);
4862        if (!g)
4863                goto out_free_tape;
4864
4865        ide_init_disk(g, drive);
4866
4867        ide_proc_register_driver(drive, &idetape_driver);
4868
4869        kref_init(&tape->kref);
4870
4871        tape->drive = drive;
4872        tape->driver = &idetape_driver;
4873        tape->disk = g;
4874
4875        g->private_data = &tape->driver;
4876
4877        drive->driver_data = tape;
4878
4879        mutex_lock(&idetape_ref_mutex);
4880        for (minor = 0; idetape_devs[minor]; minor++)
4881                ;
4882        idetape_devs[minor] = tape;
4883        mutex_unlock(&idetape_ref_mutex);
4884
4885        idetape_setup(drive, tape, minor);
4886
4887        class_device_create(idetape_sysfs_class, NULL,
4888                        MKDEV(IDETAPE_MAJOR, minor), &drive->gendev, "%s", tape->name);
4889        class_device_create(idetape_sysfs_class, NULL,
4890                        MKDEV(IDETAPE_MAJOR, minor + 128), &drive->gendev, "n%s", tape->name);
4891
4892        g->fops = &idetape_block_ops;
4893        ide_register_region(g);
4894
4895        return 0;
4896
4897out_free_tape:
4898        kfree(tape);
4899failed:
4900        return -ENODEV;
4901}
4902
4903MODULE_DESCRIPTION("ATAPI Streaming TAPE Driver");
4904MODULE_LICENSE("GPL");
4905
4906static void __exit idetape_exit (void)
4907{
4908        driver_unregister(&idetape_driver.gen_driver);
4909        class_destroy(idetape_sysfs_class);
4910        unregister_chrdev(IDETAPE_MAJOR, "ht");
4911}
4912
4913static int __init idetape_init(void)
4914{
4915        int error = 1;
4916        idetape_sysfs_class = class_create(THIS_MODULE, "ide_tape");
4917        if (IS_ERR(idetape_sysfs_class)) {
4918                idetape_sysfs_class = NULL;
4919                printk(KERN_ERR "Unable to create sysfs class for ide tapes\n");
4920                error = -EBUSY;
4921                goto out;
4922        }
4923
4924        if (register_chrdev(IDETAPE_MAJOR, "ht", &idetape_fops)) {
4925                printk(KERN_ERR "ide-tape: Failed to register character device interface\n");
4926                error = -EBUSY;
4927                goto out_free_class;
4928        }
4929
4930        error = driver_register(&idetape_driver.gen_driver);
4931        if (error)
4932                goto out_free_driver;
4933
4934        return 0;
4935
4936out_free_driver:
4937        driver_unregister(&idetape_driver.gen_driver);
4938out_free_class:
4939        class_destroy(idetape_sysfs_class);
4940out:
4941        return error;
4942}
4943
4944MODULE_ALIAS("ide:*m-tape*");
4945module_init(idetape_init);
4946module_exit(idetape_exit);
4947MODULE_ALIAS_CHARDEV_MAJOR(IDETAPE_MAJOR);
4948
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