linux/drivers/scsi/atari_scsi.c
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   1/*
   2 * atari_scsi.c -- Device dependent functions for the Atari generic SCSI port
   3 *
   4 * Copyright 1994 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
   5 *
   6 *   Loosely based on the work of Robert De Vries' team and added:
   7 *    - working real DMA
   8 *    - Falcon support (untested yet!)   ++bjoern fixed and now it works
   9 *    - lots of extensions and bug fixes.
  10 *
  11 * This file is subject to the terms and conditions of the GNU General Public
  12 * License.  See the file COPYING in the main directory of this archive
  13 * for more details.
  14 *
  15 */
  16
  17
  18/**************************************************************************/
  19/*                                                                        */
  20/* Notes for Falcon SCSI:                                                 */
  21/* ----------------------                                                 */
  22/*                                                                        */
  23/* Since the Falcon SCSI uses the ST-DMA chip, that is shared among       */
  24/* several device drivers, locking and unlocking the access to this       */
  25/* chip is required. But locking is not possible from an interrupt,       */
  26/* since it puts the process to sleep if the lock is not available.       */
  27/* This prevents "late" locking of the DMA chip, i.e. locking it just     */
  28/* before using it, since in case of disconnection-reconnection           */
  29/* commands, the DMA is started from the reselection interrupt.           */
  30/*                                                                        */
  31/* Two possible schemes for ST-DMA-locking would be:                      */
  32/*  1) The lock is taken for each command separately and disconnecting    */
  33/*     is forbidden (i.e. can_queue = 1).                                 */
  34/*  2) The DMA chip is locked when the first command comes in and         */
  35/*     released when the last command is finished and all queues are      */
  36/*     empty.                                                             */
  37/* The first alternative would result in bad performance, since the       */
  38/* interleaving of commands would not be used. The second is unfair to    */
  39/* other drivers using the ST-DMA, because the queues will seldom be      */
  40/* totally empty if there is a lot of disk traffic.                       */
  41/*                                                                        */
  42/* For this reasons I decided to employ a more elaborate scheme:          */
  43/*  - First, we give up the lock every time we can (for fairness), this    */
  44/*    means every time a command finishes and there are no other commands */
  45/*    on the disconnected queue.                                          */
  46/*  - If there are others waiting to lock the DMA chip, we stop           */
  47/*    issuing commands, i.e. moving them onto the issue queue.           */
  48/*    Because of that, the disconnected queue will run empty in a         */
  49/*    while. Instead we go to sleep on a 'fairness_queue'.                */
  50/*  - If the lock is released, all processes waiting on the fairness      */
  51/*    queue will be woken. The first of them tries to re-lock the DMA,     */
  52/*    the others wait for the first to finish this task. After that,      */
  53/*    they can all run on and do their commands...                        */
  54/* This sounds complicated (and it is it :-(), but it seems to be a       */
  55/* good compromise between fairness and performance: As long as no one     */
  56/* else wants to work with the ST-DMA chip, SCSI can go along as          */
  57/* usual. If now someone else comes, this behaviour is changed to a       */
  58/* "fairness mode": just already initiated commands are finished and      */
  59/* then the lock is released. The other one waiting will probably win     */
  60/* the race for locking the DMA, since it was waiting for longer. And     */
  61/* after it has finished, SCSI can go ahead again. Finally: I hope I      */
  62/* have not produced any deadlock possibilities!                          */
  63/*                                                                        */
  64/**************************************************************************/
  65
  66
  67
  68#include <linux/module.h>
  69
  70#define NDEBUG (0)
  71
  72#define NDEBUG_ABORT            0x00100000
  73#define NDEBUG_TAGS             0x00200000
  74#define NDEBUG_MERGING          0x00400000
  75
  76#define AUTOSENSE
  77/* For the Atari version, use only polled IO or REAL_DMA */
  78#define REAL_DMA
  79/* Support tagged queuing? (on devices that are able to... :-) */
  80#define SUPPORT_TAGS
  81#define MAX_TAGS 32
  82
  83#include <linux/types.h>
  84#include <linux/stddef.h>
  85#include <linux/ctype.h>
  86#include <linux/delay.h>
  87#include <linux/mm.h>
  88#include <linux/blkdev.h>
  89#include <linux/interrupt.h>
  90#include <linux/init.h>
  91#include <linux/nvram.h>
  92#include <linux/bitops.h>
  93
  94#include <asm/setup.h>
  95#include <asm/atarihw.h>
  96#include <asm/atariints.h>
  97#include <asm/page.h>
  98#include <asm/pgtable.h>
  99#include <asm/irq.h>
 100#include <asm/traps.h>
 101
 102#include "scsi.h"
 103#include <scsi/scsi_host.h>
 104#include "atari_scsi.h"
 105#include "NCR5380.h"
 106#include <asm/atari_stdma.h>
 107#include <asm/atari_stram.h>
 108#include <asm/io.h>
 109
 110#include <linux/stat.h>
 111
 112#define IS_A_TT()       ATARIHW_PRESENT(TT_SCSI)
 113
 114#define SCSI_DMA_WRITE_P(elt,val)                               \
 115        do {                                                    \
 116                unsigned long v = val;                          \
 117                tt_scsi_dma.elt##_lo = v & 0xff;                \
 118                v >>= 8;                                        \
 119                tt_scsi_dma.elt##_lmd = v & 0xff;               \
 120                v >>= 8;                                        \
 121                tt_scsi_dma.elt##_hmd = v & 0xff;               \
 122                v >>= 8;                                        \
 123                tt_scsi_dma.elt##_hi = v & 0xff;                \
 124        } while(0)
 125
 126#define SCSI_DMA_READ_P(elt)                                    \
 127        (((((((unsigned long)tt_scsi_dma.elt##_hi << 8) |       \
 128             (unsigned long)tt_scsi_dma.elt##_hmd) << 8) |      \
 129           (unsigned long)tt_scsi_dma.elt##_lmd) << 8) |        \
 130         (unsigned long)tt_scsi_dma.elt##_lo)
 131
 132
 133static inline void SCSI_DMA_SETADR(unsigned long adr)
 134{
 135        st_dma.dma_lo = (unsigned char)adr;
 136        MFPDELAY();
 137        adr >>= 8;
 138        st_dma.dma_md = (unsigned char)adr;
 139        MFPDELAY();
 140        adr >>= 8;
 141        st_dma.dma_hi = (unsigned char)adr;
 142        MFPDELAY();
 143}
 144
 145static inline unsigned long SCSI_DMA_GETADR(void)
 146{
 147        unsigned long adr;
 148        adr = st_dma.dma_lo;
 149        MFPDELAY();
 150        adr |= (st_dma.dma_md & 0xff) << 8;
 151        MFPDELAY();
 152        adr |= (st_dma.dma_hi & 0xff) << 16;
 153        MFPDELAY();
 154        return adr;
 155}
 156
 157static inline void ENABLE_IRQ(void)
 158{
 159        if (IS_A_TT())
 160                atari_enable_irq(IRQ_TT_MFP_SCSI);
 161        else
 162                atari_enable_irq(IRQ_MFP_FSCSI);
 163}
 164
 165static inline void DISABLE_IRQ(void)
 166{
 167        if (IS_A_TT())
 168                atari_disable_irq(IRQ_TT_MFP_SCSI);
 169        else
 170                atari_disable_irq(IRQ_MFP_FSCSI);
 171}
 172
 173
 174#define HOSTDATA_DMALEN         (((struct NCR5380_hostdata *) \
 175                                (atari_scsi_host->hostdata))->dma_len)
 176
 177/* Time (in jiffies) to wait after a reset; the SCSI standard calls for 250ms,
 178 * we usually do 0.5s to be on the safe side. But Toshiba CD-ROMs once more
 179 * need ten times the standard value... */
 180#ifndef CONFIG_ATARI_SCSI_TOSHIBA_DELAY
 181#define AFTER_RESET_DELAY       (HZ/2)
 182#else
 183#define AFTER_RESET_DELAY       (5*HZ/2)
 184#endif
 185
 186/***************************** Prototypes *****************************/
 187
 188#ifdef REAL_DMA
 189static int scsi_dma_is_ignored_buserr(unsigned char dma_stat);
 190static void atari_scsi_fetch_restbytes(void);
 191static long atari_scsi_dma_residual(struct Scsi_Host *instance);
 192static int falcon_classify_cmd(Scsi_Cmnd *cmd);
 193static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
 194                                        Scsi_Cmnd *cmd, int write_flag);
 195#endif
 196static irqreturn_t scsi_tt_intr(int irq, void *dummy);
 197static irqreturn_t scsi_falcon_intr(int irq, void *dummy);
 198static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata);
 199static void falcon_get_lock(void);
 200#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
 201static void atari_scsi_reset_boot(void);
 202#endif
 203static unsigned char atari_scsi_tt_reg_read(unsigned char reg);
 204static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value);
 205static unsigned char atari_scsi_falcon_reg_read(unsigned char reg);
 206static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value);
 207
 208/************************* End of Prototypes **************************/
 209
 210
 211static struct Scsi_Host *atari_scsi_host;
 212static unsigned char (*atari_scsi_reg_read)(unsigned char reg);
 213static void (*atari_scsi_reg_write)(unsigned char reg, unsigned char value);
 214
 215#ifdef REAL_DMA
 216static unsigned long    atari_dma_residual, atari_dma_startaddr;
 217static short            atari_dma_active;
 218/* pointer to the dribble buffer */
 219static char             *atari_dma_buffer;
 220/* precalculated physical address of the dribble buffer */
 221static unsigned long    atari_dma_phys_buffer;
 222/* != 0 tells the Falcon int handler to copy data from the dribble buffer */
 223static char             *atari_dma_orig_addr;
 224/* size of the dribble buffer; 4k seems enough, since the Falcon cannot use
 225 * scatter-gather anyway, so most transfers are 1024 byte only. In the rare
 226 * cases where requests to physical contiguous buffers have been merged, this
 227 * request is <= 4k (one page). So I don't think we have to split transfers
 228 * just due to this buffer size...
 229 */
 230#define STRAM_BUFFER_SIZE       (4096)
 231/* mask for address bits that can't be used with the ST-DMA */
 232static unsigned long    atari_dma_stram_mask;
 233#define STRAM_ADDR(a)   (((a) & atari_dma_stram_mask) == 0)
 234/* number of bytes to cut from a transfer to handle NCR overruns */
 235static int atari_read_overruns;
 236#endif
 237
 238static int setup_can_queue = -1;
 239module_param(setup_can_queue, int, 0);
 240static int setup_cmd_per_lun = -1;
 241module_param(setup_cmd_per_lun, int, 0);
 242static int setup_sg_tablesize = -1;
 243module_param(setup_sg_tablesize, int, 0);
 244#ifdef SUPPORT_TAGS
 245static int setup_use_tagged_queuing = -1;
 246module_param(setup_use_tagged_queuing, int, 0);
 247#endif
 248static int setup_hostid = -1;
 249module_param(setup_hostid, int, 0);
 250
 251
 252#if defined(REAL_DMA)
 253
 254static int scsi_dma_is_ignored_buserr(unsigned char dma_stat)
 255{
 256        int i;
 257        unsigned long addr = SCSI_DMA_READ_P(dma_addr), end_addr;
 258
 259        if (dma_stat & 0x01) {
 260
 261                /* A bus error happens when DMA-ing from the last page of a
 262                 * physical memory chunk (DMA prefetch!), but that doesn't hurt.
 263                 * Check for this case:
 264                 */
 265
 266                for (i = 0; i < m68k_num_memory; ++i) {
 267                        end_addr = m68k_memory[i].addr + m68k_memory[i].size;
 268                        if (end_addr <= addr && addr <= end_addr + 4)
 269                                return 1;
 270                }
 271        }
 272        return 0;
 273}
 274
 275
 276#if 0
 277/* Dead code... wasn't called anyway :-) and causes some trouble, because at
 278 * end-of-DMA, both SCSI ints are triggered simultaneously, so the NCR int has
 279 * to clear the DMA int pending bit before it allows other level 6 interrupts.
 280 */
 281static void scsi_dma_buserr(int irq, void *dummy)
 282{
 283        unsigned char dma_stat = tt_scsi_dma.dma_ctrl;
 284
 285        /* Don't do anything if a NCR interrupt is pending. Probably it's just
 286         * masked... */
 287        if (atari_irq_pending(IRQ_TT_MFP_SCSI))
 288                return;
 289
 290        printk("Bad SCSI DMA interrupt! dma_addr=0x%08lx dma_stat=%02x dma_cnt=%08lx\n",
 291               SCSI_DMA_READ_P(dma_addr), dma_stat, SCSI_DMA_READ_P(dma_cnt));
 292        if (dma_stat & 0x80) {
 293                if (!scsi_dma_is_ignored_buserr(dma_stat))
 294                        printk("SCSI DMA bus error -- bad DMA programming!\n");
 295        } else {
 296                /* Under normal circumstances we never should get to this point,
 297                 * since both interrupts are triggered simultaneously and the 5380
 298                 * int has higher priority. When this irq is handled, that DMA
 299                 * interrupt is cleared. So a warning message is printed here.
 300                 */
 301                printk("SCSI DMA intr ?? -- this shouldn't happen!\n");
 302        }
 303}
 304#endif
 305
 306#endif
 307
 308
 309static irqreturn_t scsi_tt_intr(int irq, void *dummy)
 310{
 311#ifdef REAL_DMA
 312        int dma_stat;
 313
 314        dma_stat = tt_scsi_dma.dma_ctrl;
 315
 316        INT_PRINTK("scsi%d: NCR5380 interrupt, DMA status = %02x\n",
 317                   atari_scsi_host->host_no, dma_stat & 0xff);
 318
 319        /* Look if it was the DMA that has interrupted: First possibility
 320         * is that a bus error occurred...
 321         */
 322        if (dma_stat & 0x80) {
 323                if (!scsi_dma_is_ignored_buserr(dma_stat)) {
 324                        printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
 325                               SCSI_DMA_READ_P(dma_addr));
 326                        printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
 327                }
 328        }
 329
 330        /* If the DMA is active but not finished, we have the case
 331         * that some other 5380 interrupt occurred within the DMA transfer.
 332         * This means we have residual bytes, if the desired end address
 333         * is not yet reached. Maybe we have to fetch some bytes from the
 334         * rest data register, too. The residual must be calculated from
 335         * the address pointer, not the counter register, because only the
 336         * addr reg counts bytes not yet written and pending in the rest
 337         * data reg!
 338         */
 339        if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
 340                atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P(dma_addr) - atari_dma_startaddr);
 341
 342                DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
 343                           atari_dma_residual);
 344
 345                if ((signed int)atari_dma_residual < 0)
 346                        atari_dma_residual = 0;
 347                if ((dma_stat & 1) == 0) {
 348                        /*
 349                         * After read operations, we maybe have to
 350                         * transport some rest bytes
 351                         */
 352                        atari_scsi_fetch_restbytes();
 353                } else {
 354                        /*
 355                         * There seems to be a nasty bug in some SCSI-DMA/NCR
 356                         * combinations: If a target disconnects while a write
 357                         * operation is going on, the address register of the
 358                         * DMA may be a few bytes farer than it actually read.
 359                         * This is probably due to DMA prefetching and a delay
 360                         * between DMA and NCR.  Experiments showed that the
 361                         * dma_addr is 9 bytes to high, but this could vary.
 362                         * The problem is, that the residual is thus calculated
 363                         * wrong and the next transfer will start behind where
 364                         * it should.  So we round up the residual to the next
 365                         * multiple of a sector size, if it isn't already a
 366                         * multiple and the originally expected transfer size
 367                         * was.  The latter condition is there to ensure that
 368                         * the correction is taken only for "real" data
 369                         * transfers and not for, e.g., the parameters of some
 370                         * other command.  These shouldn't disconnect anyway.
 371                         */
 372                        if (atari_dma_residual & 0x1ff) {
 373                                DMA_PRINTK("SCSI DMA: DMA bug corrected, "
 374                                           "difference %ld bytes\n",
 375                                           512 - (atari_dma_residual & 0x1ff));
 376                                atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
 377                        }
 378                }
 379                tt_scsi_dma.dma_ctrl = 0;
 380        }
 381
 382        /* If the DMA is finished, fetch the rest bytes and turn it off */
 383        if (dma_stat & 0x40) {
 384                atari_dma_residual = 0;
 385                if ((dma_stat & 1) == 0)
 386                        atari_scsi_fetch_restbytes();
 387                tt_scsi_dma.dma_ctrl = 0;
 388        }
 389
 390#endif /* REAL_DMA */
 391
 392        NCR5380_intr(irq, dummy);
 393
 394#if 0
 395        /* To be sure the int is not masked */
 396        atari_enable_irq(IRQ_TT_MFP_SCSI);
 397#endif
 398        return IRQ_HANDLED;
 399}
 400
 401
 402static irqreturn_t scsi_falcon_intr(int irq, void *dummy)
 403{
 404#ifdef REAL_DMA
 405        int dma_stat;
 406
 407        /* Turn off DMA and select sector counter register before
 408         * accessing the status register (Atari recommendation!)
 409         */
 410        st_dma.dma_mode_status = 0x90;
 411        dma_stat = st_dma.dma_mode_status;
 412
 413        /* Bit 0 indicates some error in the DMA process... don't know
 414         * what happened exactly (no further docu).
 415         */
 416        if (!(dma_stat & 0x01)) {
 417                /* DMA error */
 418                printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
 419        }
 420
 421        /* If the DMA was active, but now bit 1 is not clear, it is some
 422         * other 5380 interrupt that finishes the DMA transfer. We have to
 423         * calculate the number of residual bytes and give a warning if
 424         * bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
 425         */
 426        if (atari_dma_active && (dma_stat & 0x02)) {
 427                unsigned long transferred;
 428
 429                transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
 430                /* The ST-DMA address is incremented in 2-byte steps, but the
 431                 * data are written only in 16-byte chunks. If the number of
 432                 * transferred bytes is not divisible by 16, the remainder is
 433                 * lost somewhere in outer space.
 434                 */
 435                if (transferred & 15)
 436                        printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
 437                               "ST-DMA fifo\n", transferred & 15);
 438
 439                atari_dma_residual = HOSTDATA_DMALEN - transferred;
 440                DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
 441                           atari_dma_residual);
 442        } else
 443                atari_dma_residual = 0;
 444        atari_dma_active = 0;
 445
 446        if (atari_dma_orig_addr) {
 447                /* If the dribble buffer was used on a read operation, copy the DMA-ed
 448                 * data to the original destination address.
 449                 */
 450                memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
 451                       HOSTDATA_DMALEN - atari_dma_residual);
 452                atari_dma_orig_addr = NULL;
 453        }
 454
 455#endif /* REAL_DMA */
 456
 457        NCR5380_intr(irq, dummy);
 458        return IRQ_HANDLED;
 459}
 460
 461
 462#ifdef REAL_DMA
 463static void atari_scsi_fetch_restbytes(void)
 464{
 465        int nr;
 466        char *src, *dst;
 467        unsigned long phys_dst;
 468
 469        /* fetch rest bytes in the DMA register */
 470        phys_dst = SCSI_DMA_READ_P(dma_addr);
 471        nr = phys_dst & 3;
 472        if (nr) {
 473                /* there are 'nr' bytes left for the last long address
 474                   before the DMA pointer */
 475                phys_dst ^= nr;
 476                DMA_PRINTK("SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
 477                           nr, phys_dst);
 478                /* The content of the DMA pointer is a physical address!  */
 479                dst = phys_to_virt(phys_dst);
 480                DMA_PRINTK(" = virt addr %p\n", dst);
 481                for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
 482                        *dst++ = *src++;
 483        }
 484}
 485#endif /* REAL_DMA */
 486
 487
 488static int falcon_got_lock = 0;
 489static DECLARE_WAIT_QUEUE_HEAD(falcon_fairness_wait);
 490static int falcon_trying_lock = 0;
 491static DECLARE_WAIT_QUEUE_HEAD(falcon_try_wait);
 492static int falcon_dont_release = 0;
 493
 494/* This function releases the lock on the DMA chip if there is no
 495 * connected command and the disconnected queue is empty. On
 496 * releasing, instances of falcon_get_lock are awoken, that put
 497 * themselves to sleep for fairness. They can now try to get the lock
 498 * again (but others waiting longer more probably will win).
 499 */
 500
 501static void falcon_release_lock_if_possible(struct NCR5380_hostdata *hostdata)
 502{
 503        unsigned long flags;
 504
 505        if (IS_A_TT())
 506                return;
 507
 508        local_irq_save(flags);
 509
 510        if (falcon_got_lock && !hostdata->disconnected_queue &&
 511            !hostdata->issue_queue && !hostdata->connected) {
 512
 513                if (falcon_dont_release) {
 514#if 0
 515                        printk("WARNING: Lock release not allowed. Ignored\n");
 516#endif
 517                        local_irq_restore(flags);
 518                        return;
 519                }
 520                falcon_got_lock = 0;
 521                stdma_release();
 522                wake_up(&falcon_fairness_wait);
 523        }
 524
 525        local_irq_restore(flags);
 526}
 527
 528/* This function manages the locking of the ST-DMA.
 529 * If the DMA isn't locked already for SCSI, it tries to lock it by
 530 * calling stdma_lock(). But if the DMA is locked by the SCSI code and
 531 * there are other drivers waiting for the chip, we do not issue the
 532 * command immediately but wait on 'falcon_fairness_queue'. We will be
 533 * waked up when the DMA is unlocked by some SCSI interrupt. After that
 534 * we try to get the lock again.
 535 * But we must be prepared that more than one instance of
 536 * falcon_get_lock() is waiting on the fairness queue. They should not
 537 * try all at once to call stdma_lock(), one is enough! For that, the
 538 * first one sets 'falcon_trying_lock', others that see that variable
 539 * set wait on the queue 'falcon_try_wait'.
 540 * Complicated, complicated.... Sigh...
 541 */
 542
 543static void falcon_get_lock(void)
 544{
 545        unsigned long flags;
 546
 547        if (IS_A_TT())
 548                return;
 549
 550        local_irq_save(flags);
 551
 552        while (!in_irq() && falcon_got_lock && stdma_others_waiting())
 553                sleep_on(&falcon_fairness_wait);
 554
 555        while (!falcon_got_lock) {
 556                if (in_irq())
 557                        panic("Falcon SCSI hasn't ST-DMA lock in interrupt");
 558                if (!falcon_trying_lock) {
 559                        falcon_trying_lock = 1;
 560                        stdma_lock(scsi_falcon_intr, NULL);
 561                        falcon_got_lock = 1;
 562                        falcon_trying_lock = 0;
 563                        wake_up(&falcon_try_wait);
 564                } else {
 565                        sleep_on(&falcon_try_wait);
 566                }
 567        }
 568
 569        local_irq_restore(flags);
 570        if (!falcon_got_lock)
 571                panic("Falcon SCSI: someone stole the lock :-(\n");
 572}
 573
 574
 575static int __init atari_scsi_detect(struct scsi_host_template *host)
 576{
 577        static int called = 0;
 578        struct Scsi_Host *instance;
 579
 580        if (!MACH_IS_ATARI ||
 581            (!ATARIHW_PRESENT(ST_SCSI) && !ATARIHW_PRESENT(TT_SCSI)) ||
 582            called)
 583                return 0;
 584
 585        host->proc_name = "Atari";
 586
 587        atari_scsi_reg_read  = IS_A_TT() ? atari_scsi_tt_reg_read :
 588                                           atari_scsi_falcon_reg_read;
 589        atari_scsi_reg_write = IS_A_TT() ? atari_scsi_tt_reg_write :
 590                                           atari_scsi_falcon_reg_write;
 591
 592        /* setup variables */
 593        host->can_queue =
 594                (setup_can_queue > 0) ? setup_can_queue :
 595                IS_A_TT() ? ATARI_TT_CAN_QUEUE : ATARI_FALCON_CAN_QUEUE;
 596        host->cmd_per_lun =
 597                (setup_cmd_per_lun > 0) ? setup_cmd_per_lun :
 598                IS_A_TT() ? ATARI_TT_CMD_PER_LUN : ATARI_FALCON_CMD_PER_LUN;
 599        /* Force sg_tablesize to 0 on a Falcon! */
 600        host->sg_tablesize =
 601                !IS_A_TT() ? ATARI_FALCON_SG_TABLESIZE :
 602                (setup_sg_tablesize >= 0) ? setup_sg_tablesize : ATARI_TT_SG_TABLESIZE;
 603
 604        if (setup_hostid >= 0)
 605                host->this_id = setup_hostid;
 606        else {
 607                /* use 7 as default */
 608                host->this_id = 7;
 609                /* Test if a host id is set in the NVRam */
 610                if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
 611                        unsigned char b = nvram_read_byte( 14 );
 612                        /* Arbitration enabled? (for TOS) If yes, use configured host ID */
 613                        if (b & 0x80)
 614                                host->this_id = b & 7;
 615                }
 616        }
 617
 618#ifdef SUPPORT_TAGS
 619        if (setup_use_tagged_queuing < 0)
 620                setup_use_tagged_queuing = DEFAULT_USE_TAGGED_QUEUING;
 621#endif
 622#ifdef REAL_DMA
 623        /* If running on a Falcon and if there's TT-Ram (i.e., more than one
 624         * memory block, since there's always ST-Ram in a Falcon), then allocate a
 625         * STRAM_BUFFER_SIZE byte dribble buffer for transfers from/to alternative
 626         * Ram.
 627         */
 628        if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) &&
 629            !ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) {
 630                atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
 631                if (!atari_dma_buffer) {
 632                        printk(KERN_ERR "atari_scsi_detect: can't allocate ST-RAM "
 633                                        "double buffer\n");
 634                        return 0;
 635                }
 636                atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
 637                atari_dma_orig_addr = 0;
 638        }
 639#endif
 640        instance = scsi_register(host, sizeof(struct NCR5380_hostdata));
 641        if (instance == NULL) {
 642                atari_stram_free(atari_dma_buffer);
 643                atari_dma_buffer = 0;
 644                return 0;
 645        }
 646        atari_scsi_host = instance;
 647        /*
 648         * Set irq to 0, to avoid that the mid-level code disables our interrupt
 649         * during queue_command calls. This is completely unnecessary, and even
 650         * worse causes bad problems on the Falcon, where the int is shared with
 651         * IDE and floppy!
 652         */
 653       instance->irq = 0;
 654
 655#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
 656        atari_scsi_reset_boot();
 657#endif
 658        NCR5380_init(instance, 0);
 659
 660        if (IS_A_TT()) {
 661
 662                /* This int is actually "pseudo-slow", i.e. it acts like a slow
 663                 * interrupt after having cleared the pending flag for the DMA
 664                 * interrupt. */
 665                if (request_irq(IRQ_TT_MFP_SCSI, scsi_tt_intr, IRQ_TYPE_SLOW,
 666                                 "SCSI NCR5380", instance)) {
 667                        printk(KERN_ERR "atari_scsi_detect: cannot allocate irq %d, aborting",IRQ_TT_MFP_SCSI);
 668                        scsi_unregister(atari_scsi_host);
 669                        atari_stram_free(atari_dma_buffer);
 670                        atari_dma_buffer = 0;
 671                        return 0;
 672                }
 673                tt_mfp.active_edge |= 0x80;             /* SCSI int on L->H */
 674#ifdef REAL_DMA
 675                tt_scsi_dma.dma_ctrl = 0;
 676                atari_dma_residual = 0;
 677
 678                if (MACH_IS_MEDUSA) {
 679                        /* While the read overruns (described by Drew Eckhardt in
 680                         * NCR5380.c) never happened on TTs, they do in fact on the Medusa
 681                         * (This was the cause why SCSI didn't work right for so long
 682                         * there.) Since handling the overruns slows down a bit, I turned
 683                         * the #ifdef's into a runtime condition.
 684                         *
 685                         * In principle it should be sufficient to do max. 1 byte with
 686                         * PIO, but there is another problem on the Medusa with the DMA
 687                         * rest data register. So 'atari_read_overruns' is currently set
 688                         * to 4 to avoid having transfers that aren't a multiple of 4. If
 689                         * the rest data bug is fixed, this can be lowered to 1.
 690                         */
 691                        atari_read_overruns = 4;
 692                }
 693#endif /*REAL_DMA*/
 694        } else { /* ! IS_A_TT */
 695
 696                /* Nothing to do for the interrupt: the ST-DMA is initialized
 697                 * already by atari_init_INTS()
 698                 */
 699
 700#ifdef REAL_DMA
 701                atari_dma_residual = 0;
 702                atari_dma_active = 0;
 703                atari_dma_stram_mask = (ATARIHW_PRESENT(EXTD_DMA) ? 0x00000000
 704                                        : 0xff000000);
 705#endif
 706        }
 707
 708        printk(KERN_INFO "scsi%d: options CAN_QUEUE=%d CMD_PER_LUN=%d SCAT-GAT=%d "
 709#ifdef SUPPORT_TAGS
 710                        "TAGGED-QUEUING=%s "
 711#endif
 712                        "HOSTID=%d",
 713                        instance->host_no, instance->hostt->can_queue,
 714                        instance->hostt->cmd_per_lun,
 715                        instance->hostt->sg_tablesize,
 716#ifdef SUPPORT_TAGS
 717                        setup_use_tagged_queuing ? "yes" : "no",
 718#endif
 719                        instance->hostt->this_id );
 720        NCR5380_print_options(instance);
 721        printk("\n");
 722
 723        called = 1;
 724        return 1;
 725}
 726
 727static int atari_scsi_release(struct Scsi_Host *sh)
 728{
 729        if (IS_A_TT())
 730                free_irq(IRQ_TT_MFP_SCSI, sh);
 731        if (atari_dma_buffer)
 732                atari_stram_free(atari_dma_buffer);
 733        NCR5380_exit(sh);
 734        return 1;
 735}
 736
 737#ifndef MODULE
 738static int __init atari_scsi_setup(char *str)
 739{
 740        /* Format of atascsi parameter is:
 741         *   atascsi=<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags>
 742         * Defaults depend on TT or Falcon, hostid determined at run time.
 743         * Negative values mean don't change.
 744         */
 745        int ints[6];
 746
 747        get_options(str, ARRAY_SIZE(ints), ints);
 748
 749        if (ints[0] < 1) {
 750                printk("atari_scsi_setup: no arguments!\n");
 751                return 0;
 752        }
 753
 754        if (ints[0] >= 1) {
 755                if (ints[1] > 0)
 756                        /* no limits on this, just > 0 */
 757                        setup_can_queue = ints[1];
 758        }
 759        if (ints[0] >= 2) {
 760                if (ints[2] > 0)
 761                        setup_cmd_per_lun = ints[2];
 762        }
 763        if (ints[0] >= 3) {
 764                if (ints[3] >= 0) {
 765                        setup_sg_tablesize = ints[3];
 766                        /* Must be <= SG_ALL (255) */
 767                        if (setup_sg_tablesize > SG_ALL)
 768                                setup_sg_tablesize = SG_ALL;
 769                }
 770        }
 771        if (ints[0] >= 4) {
 772                /* Must be between 0 and 7 */
 773                if (ints[4] >= 0 && ints[4] <= 7)
 774                        setup_hostid = ints[4];
 775                else if (ints[4] > 7)
 776                        printk("atari_scsi_setup: invalid host ID %d !\n", ints[4]);
 777        }
 778#ifdef SUPPORT_TAGS
 779        if (ints[0] >= 5) {
 780                if (ints[5] >= 0)
 781                        setup_use_tagged_queuing = !!ints[5];
 782        }
 783#endif
 784
 785        return 1;
 786}
 787
 788__setup("atascsi=", atari_scsi_setup);
 789#endif /* !MODULE */
 790
 791static int atari_scsi_bus_reset(Scsi_Cmnd *cmd)
 792{
 793        int rv;
 794        struct NCR5380_hostdata *hostdata =
 795                (struct NCR5380_hostdata *)cmd->device->host->hostdata;
 796
 797        /* For doing the reset, SCSI interrupts must be disabled first,
 798         * since the 5380 raises its IRQ line while _RST is active and we
 799         * can't disable interrupts completely, since we need the timer.
 800         */
 801        /* And abort a maybe active DMA transfer */
 802        if (IS_A_TT()) {
 803                atari_turnoff_irq(IRQ_TT_MFP_SCSI);
 804#ifdef REAL_DMA
 805                tt_scsi_dma.dma_ctrl = 0;
 806#endif /* REAL_DMA */
 807        } else {
 808                atari_turnoff_irq(IRQ_MFP_FSCSI);
 809#ifdef REAL_DMA
 810                st_dma.dma_mode_status = 0x90;
 811                atari_dma_active = 0;
 812                atari_dma_orig_addr = NULL;
 813#endif /* REAL_DMA */
 814        }
 815
 816        rv = NCR5380_bus_reset(cmd);
 817
 818        /* Re-enable ints */
 819        if (IS_A_TT()) {
 820                atari_turnon_irq(IRQ_TT_MFP_SCSI);
 821        } else {
 822                atari_turnon_irq(IRQ_MFP_FSCSI);
 823        }
 824        if ((rv & SCSI_RESET_ACTION) == SCSI_RESET_SUCCESS)
 825                falcon_release_lock_if_possible(hostdata);
 826
 827        return rv;
 828}
 829
 830
 831#ifdef CONFIG_ATARI_SCSI_RESET_BOOT
 832static void __init atari_scsi_reset_boot(void)
 833{
 834        unsigned long end;
 835
 836        /*
 837         * Do a SCSI reset to clean up the bus during initialization. No messing
 838         * with the queues, interrupts, or locks necessary here.
 839         */
 840
 841        printk("Atari SCSI: resetting the SCSI bus...");
 842
 843        /* get in phase */
 844        NCR5380_write(TARGET_COMMAND_REG,
 845                      PHASE_SR_TO_TCR(NCR5380_read(STATUS_REG)));
 846
 847        /* assert RST */
 848        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE | ICR_ASSERT_RST);
 849        /* The min. reset hold time is 25us, so 40us should be enough */
 850        udelay(50);
 851        /* reset RST and interrupt */
 852        NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 853        NCR5380_read(RESET_PARITY_INTERRUPT_REG);
 854
 855        end = jiffies + AFTER_RESET_DELAY;
 856        while (time_before(jiffies, end))
 857                barrier();
 858
 859        printk(" done\n");
 860}
 861#endif
 862
 863
 864static const char *atari_scsi_info(struct Scsi_Host *host)
 865{
 866        /* atari_scsi_detect() is verbose enough... */
 867        static const char string[] = "Atari native SCSI";
 868        return string;
 869}
 870
 871
 872#if defined(REAL_DMA)
 873
 874static unsigned long atari_scsi_dma_setup(struct Scsi_Host *instance,
 875                                          void *data, unsigned long count,
 876                                          int dir)
 877{
 878        unsigned long addr = virt_to_phys(data);
 879
 880        DMA_PRINTK("scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
 881                   "dir = %d\n", instance->host_no, data, addr, count, dir);
 882
 883        if (!IS_A_TT() && !STRAM_ADDR(addr)) {
 884                /* If we have a non-DMAable address on a Falcon, use the dribble
 885                 * buffer; 'orig_addr' != 0 in the read case tells the interrupt
 886                 * handler to copy data from the dribble buffer to the originally
 887                 * wanted address.
 888                 */
 889                if (dir)
 890                        memcpy(atari_dma_buffer, data, count);
 891                else
 892                        atari_dma_orig_addr = data;
 893                addr = atari_dma_phys_buffer;
 894        }
 895
 896        atari_dma_startaddr = addr;     /* Needed for calculating residual later. */
 897
 898        /* Cache cleanup stuff: On writes, push any dirty cache out before sending
 899         * it to the peripheral. (Must be done before DMA setup, since at least
 900         * the ST-DMA begins to fill internal buffers right after setup. For
 901         * reads, invalidate any cache, may be altered after DMA without CPU
 902         * knowledge.
 903         *
 904         * ++roman: For the Medusa, there's no need at all for that cache stuff,
 905         * because the hardware does bus snooping (fine!).
 906         */
 907        dma_cache_maintenance(addr, count, dir);
 908
 909        if (count == 0)
 910                printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
 911
 912        if (IS_A_TT()) {
 913                tt_scsi_dma.dma_ctrl = dir;
 914                SCSI_DMA_WRITE_P(dma_addr, addr);
 915                SCSI_DMA_WRITE_P(dma_cnt, count);
 916                tt_scsi_dma.dma_ctrl = dir | 2;
 917        } else { /* ! IS_A_TT */
 918
 919                /* set address */
 920                SCSI_DMA_SETADR(addr);
 921
 922                /* toggle direction bit to clear FIFO and set DMA direction */
 923                dir <<= 8;
 924                st_dma.dma_mode_status = 0x90 | dir;
 925                st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
 926                st_dma.dma_mode_status = 0x90 | dir;
 927                udelay(40);
 928                /* On writes, round up the transfer length to the next multiple of 512
 929                 * (see also comment at atari_dma_xfer_len()). */
 930                st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
 931                udelay(40);
 932                st_dma.dma_mode_status = 0x10 | dir;
 933                udelay(40);
 934                /* need not restore value of dir, only boolean value is tested */
 935                atari_dma_active = 1;
 936        }
 937
 938        return count;
 939}
 940
 941
 942static long atari_scsi_dma_residual(struct Scsi_Host *instance)
 943{
 944        return atari_dma_residual;
 945}
 946
 947
 948#define CMD_SURELY_BLOCK_MODE   0
 949#define CMD_SURELY_BYTE_MODE    1
 950#define CMD_MODE_UNKNOWN                2
 951
 952static int falcon_classify_cmd(Scsi_Cmnd *cmd)
 953{
 954        unsigned char opcode = cmd->cmnd[0];
 955
 956        if (opcode == READ_DEFECT_DATA || opcode == READ_LONG ||
 957            opcode == READ_BUFFER)
 958                return CMD_SURELY_BYTE_MODE;
 959        else if (opcode == READ_6 || opcode == READ_10 ||
 960                 opcode == 0xa8 /* READ_12 */ || opcode == READ_REVERSE ||
 961                 opcode == RECOVER_BUFFERED_DATA) {
 962                /* In case of a sequential-access target (tape), special care is
 963                 * needed here: The transfer is block-mode only if the 'fixed' bit is
 964                 * set! */
 965                if (cmd->device->type == TYPE_TAPE && !(cmd->cmnd[1] & 1))
 966                        return CMD_SURELY_BYTE_MODE;
 967                else
 968                        return CMD_SURELY_BLOCK_MODE;
 969        } else
 970                return CMD_MODE_UNKNOWN;
 971}
 972
 973
 974/* This function calculates the number of bytes that can be transferred via
 975 * DMA. On the TT, this is arbitrary, but on the Falcon we have to use the
 976 * ST-DMA chip. There are only multiples of 512 bytes possible and max.
 977 * 255*512 bytes :-( This means also, that defining READ_OVERRUNS is not
 978 * possible on the Falcon, since that would require to program the DMA for
 979 * n*512 - atari_read_overrun bytes. But it seems that the Falcon doesn't have
 980 * the overrun problem, so this question is academic :-)
 981 */
 982
 983static unsigned long atari_dma_xfer_len(unsigned long wanted_len,
 984                                        Scsi_Cmnd *cmd, int write_flag)
 985{
 986        unsigned long   possible_len, limit;
 987
 988        if (IS_A_TT())
 989                /* TT SCSI DMA can transfer arbitrary #bytes */
 990                return wanted_len;
 991
 992        /* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
 993         * 255*512 bytes, but this should be enough)
 994         *
 995         * ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
 996         * that return a number of bytes which cannot be known beforehand. In this
 997         * case, the given transfer length is an "allocation length". Now it
 998         * can happen that this allocation length is a multiple of 512 bytes and
 999         * the DMA is used. But if not n*512 bytes really arrive, some input data
1000         * will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
1001         * between commands that do block transfers and those that do byte
1002         * transfers. But this isn't easy... there are lots of vendor specific
1003         * commands, and the user can issue any command via the
1004         * SCSI_IOCTL_SEND_COMMAND.
1005         *
1006         * The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
1007         * 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
1008         * and 3), the thing to do is obvious: allow any number of blocks via DMA
1009         * or none. In case 2), we apply some heuristic: Byte mode is assumed if
1010         * the transfer (allocation) length is < 1024, hoping that no cmd. not
1011         * explicitly known as byte mode have such big allocation lengths...
1012         * BTW, all the discussion above applies only to reads. DMA writes are
1013         * unproblematic anyways, since the targets aborts the transfer after
1014         * receiving a sufficient number of bytes.
1015         *
1016         * Another point: If the transfer is from/to an non-ST-RAM address, we
1017         * use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
1018         */
1019
1020        if (write_flag) {
1021                /* Write operation can always use the DMA, but the transfer size must
1022                 * be rounded up to the next multiple of 512 (atari_dma_setup() does
1023                 * this).
1024                 */
1025                possible_len = wanted_len;
1026        } else {
1027                /* Read operations: if the wanted transfer length is not a multiple of
1028                 * 512, we cannot use DMA, since the ST-DMA cannot split transfers
1029                 * (no interrupt on DMA finished!)
1030                 */
1031                if (wanted_len & 0x1ff)
1032                        possible_len = 0;
1033                else {
1034                        /* Now classify the command (see above) and decide whether it is
1035                         * allowed to do DMA at all */
1036                        switch (falcon_classify_cmd(cmd)) {
1037                        case CMD_SURELY_BLOCK_MODE:
1038                                possible_len = wanted_len;
1039                                break;
1040                        case CMD_SURELY_BYTE_MODE:
1041                                possible_len = 0; /* DMA prohibited */
1042                                break;
1043                        case CMD_MODE_UNKNOWN:
1044                        default:
1045                                /* For unknown commands assume block transfers if the transfer
1046                                 * size/allocation length is >= 1024 */
1047                                possible_len = (wanted_len < 1024) ? 0 : wanted_len;
1048                                break;
1049                        }
1050                }
1051        }
1052
1053        /* Last step: apply the hard limit on DMA transfers */
1054        limit = (atari_dma_buffer && !STRAM_ADDR(virt_to_phys(cmd->SCp.ptr))) ?
1055                    STRAM_BUFFER_SIZE : 255*512;
1056        if (possible_len > limit)
1057                possible_len = limit;
1058
1059        if (possible_len != wanted_len)
1060                DMA_PRINTK("Sorry, must cut DMA transfer size to %ld bytes "
1061                           "instead of %ld\n", possible_len, wanted_len);
1062
1063        return possible_len;
1064}
1065
1066
1067#endif  /* REAL_DMA */
1068
1069
1070/* NCR5380 register access functions
1071 *
1072 * There are separate functions for TT and Falcon, because the access
1073 * methods are quite different. The calling macros NCR5380_read and
1074 * NCR5380_write call these functions via function pointers.
1075 */
1076
1077static unsigned char atari_scsi_tt_reg_read(unsigned char reg)
1078{
1079        return tt_scsi_regp[reg * 2];
1080}
1081
1082static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value)
1083{
1084        tt_scsi_regp[reg * 2] = value;
1085}
1086
1087static unsigned char atari_scsi_falcon_reg_read(unsigned char reg)
1088{
1089        dma_wd.dma_mode_status= (u_short)(0x88 + reg);
1090        return (u_char)dma_wd.fdc_acces_seccount;
1091}
1092
1093static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value)
1094{
1095        dma_wd.dma_mode_status = (u_short)(0x88 + reg);
1096        dma_wd.fdc_acces_seccount = (u_short)value;
1097}
1098
1099
1100#include "atari_NCR5380.c"
1101
1102static struct scsi_host_template driver_template = {
1103        .show_info              = atari_scsi_show_info,
1104        .name                   = "Atari native SCSI",
1105        .detect                 = atari_scsi_detect,
1106        .release                = atari_scsi_release,
1107        .info                   = atari_scsi_info,
1108        .queuecommand           = atari_scsi_queue_command,
1109        .eh_abort_handler       = atari_scsi_abort,
1110        .eh_bus_reset_handler   = atari_scsi_bus_reset,
1111        .can_queue              = 0, /* initialized at run-time */
1112        .this_id                = 0, /* initialized at run-time */
1113        .sg_tablesize           = 0, /* initialized at run-time */
1114        .cmd_per_lun            = 0, /* initialized at run-time */
1115        .use_clustering         = DISABLE_CLUSTERING
1116};
1117
1118
1119#include "scsi_module.c"
1120
1121MODULE_LICENSE("GPL");
1122
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