linux/drivers/ide/ide-io.c
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   1/*
   2 *      IDE I/O functions
   3 *
   4 *      Basic PIO and command management functionality.
   5 *
   6 * This code was split off from ide.c. See ide.c for history and original
   7 * copyrights.
   8 *
   9 * This program is free software; you can redistribute it and/or modify it
  10 * under the terms of the GNU General Public License as published by the
  11 * Free Software Foundation; either version 2, or (at your option) any
  12 * later version.
  13 *
  14 * This program is distributed in the hope that it will be useful, but
  15 * WITHOUT ANY WARRANTY; without even the implied warranty of
  16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 * General Public License for more details.
  18 *
  19 * For the avoidance of doubt the "preferred form" of this code is one which
  20 * is in an open non patent encumbered format. Where cryptographic key signing
  21 * forms part of the process of creating an executable the information
  22 * including keys needed to generate an equivalently functional executable
  23 * are deemed to be part of the source code.
  24 */
  25 
  26 
  27#include <linux/module.h>
  28#include <linux/types.h>
  29#include <linux/string.h>
  30#include <linux/kernel.h>
  31#include <linux/timer.h>
  32#include <linux/mm.h>
  33#include <linux/interrupt.h>
  34#include <linux/major.h>
  35#include <linux/errno.h>
  36#include <linux/genhd.h>
  37#include <linux/blkpg.h>
  38#include <linux/slab.h>
  39#include <linux/init.h>
  40#include <linux/pci.h>
  41#include <linux/delay.h>
  42#include <linux/ide.h>
  43#include <linux/completion.h>
  44#include <linux/reboot.h>
  45#include <linux/cdrom.h>
  46#include <linux/seq_file.h>
  47#include <linux/device.h>
  48#include <linux/kmod.h>
  49#include <linux/scatterlist.h>
  50#include <linux/bitops.h>
  51
  52#include <asm/byteorder.h>
  53#include <asm/irq.h>
  54#include <asm/uaccess.h>
  55#include <asm/io.h>
  56
  57int ide_end_rq(ide_drive_t *drive, struct request *rq, int error,
  58               unsigned int nr_bytes)
  59{
  60        /*
  61         * decide whether to reenable DMA -- 3 is a random magic for now,
  62         * if we DMA timeout more than 3 times, just stay in PIO
  63         */
  64        if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
  65            drive->retry_pio <= 3) {
  66                drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
  67                ide_dma_on(drive);
  68        }
  69
  70        return blk_end_request(rq, error, nr_bytes);
  71}
  72EXPORT_SYMBOL_GPL(ide_end_rq);
  73
  74void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err)
  75{
  76        const struct ide_tp_ops *tp_ops = drive->hwif->tp_ops;
  77        struct ide_taskfile *tf = &cmd->tf;
  78        struct request *rq = cmd->rq;
  79        u8 tf_cmd = tf->command;
  80
  81        tf->error = err;
  82        tf->status = stat;
  83
  84        if (cmd->ftf_flags & IDE_FTFLAG_IN_DATA) {
  85                u8 data[2];
  86
  87                tp_ops->input_data(drive, cmd, data, 2);
  88
  89                cmd->tf.data  = data[0];
  90                cmd->hob.data = data[1];
  91        }
  92
  93        ide_tf_readback(drive, cmd);
  94
  95        if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) &&
  96            tf_cmd == ATA_CMD_IDLEIMMEDIATE) {
  97                if (tf->lbal != 0xc4) {
  98                        printk(KERN_ERR "%s: head unload failed!\n",
  99                               drive->name);
 100                        ide_tf_dump(drive->name, cmd);
 101                } else
 102                        drive->dev_flags |= IDE_DFLAG_PARKED;
 103        }
 104
 105        if (rq && rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
 106                struct ide_cmd *orig_cmd = rq->special;
 107
 108                if (cmd->tf_flags & IDE_TFLAG_DYN)
 109                        kfree(orig_cmd);
 110                else
 111                        memcpy(orig_cmd, cmd, sizeof(*cmd));
 112        }
 113}
 114
 115int ide_complete_rq(ide_drive_t *drive, int error, unsigned int nr_bytes)
 116{
 117        ide_hwif_t *hwif = drive->hwif;
 118        struct request *rq = hwif->rq;
 119        int rc;
 120
 121        /*
 122         * if failfast is set on a request, override number of sectors
 123         * and complete the whole request right now
 124         */
 125        if (blk_noretry_request(rq) && error <= 0)
 126                nr_bytes = blk_rq_sectors(rq) << 9;
 127
 128        rc = ide_end_rq(drive, rq, error, nr_bytes);
 129        if (rc == 0)
 130                hwif->rq = NULL;
 131
 132        return rc;
 133}
 134EXPORT_SYMBOL(ide_complete_rq);
 135
 136void ide_kill_rq(ide_drive_t *drive, struct request *rq)
 137{
 138        u8 drv_req = (rq->cmd_type == REQ_TYPE_SPECIAL) && rq->rq_disk;
 139        u8 media = drive->media;
 140
 141        drive->failed_pc = NULL;
 142
 143        if ((media == ide_floppy || media == ide_tape) && drv_req) {
 144                rq->errors = 0;
 145        } else {
 146                if (media == ide_tape)
 147                        rq->errors = IDE_DRV_ERROR_GENERAL;
 148                else if (rq->cmd_type != REQ_TYPE_FS && rq->errors == 0)
 149                        rq->errors = -EIO;
 150        }
 151
 152        ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
 153}
 154
 155static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 156{
 157        tf->nsect   = drive->sect;
 158        tf->lbal    = drive->sect;
 159        tf->lbam    = drive->cyl;
 160        tf->lbah    = drive->cyl >> 8;
 161        tf->device  = (drive->head - 1) | drive->select;
 162        tf->command = ATA_CMD_INIT_DEV_PARAMS;
 163}
 164
 165static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 166{
 167        tf->nsect   = drive->sect;
 168        tf->command = ATA_CMD_RESTORE;
 169}
 170
 171static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 172{
 173        tf->nsect   = drive->mult_req;
 174        tf->command = ATA_CMD_SET_MULTI;
 175}
 176
 177/**
 178 *      do_special              -       issue some special commands
 179 *      @drive: drive the command is for
 180 *
 181 *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
 182 *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
 183 */
 184
 185static ide_startstop_t do_special(ide_drive_t *drive)
 186{
 187        struct ide_cmd cmd;
 188
 189#ifdef DEBUG
 190        printk(KERN_DEBUG "%s: %s: 0x%02x\n", drive->name, __func__,
 191                drive->special_flags);
 192#endif
 193        if (drive->media != ide_disk) {
 194                drive->special_flags = 0;
 195                drive->mult_req = 0;
 196                return ide_stopped;
 197        }
 198
 199        memset(&cmd, 0, sizeof(cmd));
 200        cmd.protocol = ATA_PROT_NODATA;
 201
 202        if (drive->special_flags & IDE_SFLAG_SET_GEOMETRY) {
 203                drive->special_flags &= ~IDE_SFLAG_SET_GEOMETRY;
 204                ide_tf_set_specify_cmd(drive, &cmd.tf);
 205        } else if (drive->special_flags & IDE_SFLAG_RECALIBRATE) {
 206                drive->special_flags &= ~IDE_SFLAG_RECALIBRATE;
 207                ide_tf_set_restore_cmd(drive, &cmd.tf);
 208        } else if (drive->special_flags & IDE_SFLAG_SET_MULTMODE) {
 209                drive->special_flags &= ~IDE_SFLAG_SET_MULTMODE;
 210                ide_tf_set_setmult_cmd(drive, &cmd.tf);
 211        } else
 212                BUG();
 213
 214        cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
 215        cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
 216        cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER;
 217
 218        do_rw_taskfile(drive, &cmd);
 219
 220        return ide_started;
 221}
 222
 223void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
 224{
 225        ide_hwif_t *hwif = drive->hwif;
 226        struct scatterlist *sg = hwif->sg_table;
 227        struct request *rq = cmd->rq;
 228
 229        cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
 230}
 231EXPORT_SYMBOL_GPL(ide_map_sg);
 232
 233void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
 234{
 235        cmd->nbytes = cmd->nleft = nr_bytes;
 236        cmd->cursg_ofs = 0;
 237        cmd->cursg = NULL;
 238}
 239EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 240
 241/**
 242 *      execute_drive_command   -       issue special drive command
 243 *      @drive: the drive to issue the command on
 244 *      @rq: the request structure holding the command
 245 *
 246 *      execute_drive_cmd() issues a special drive command,  usually 
 247 *      initiated by ioctl() from the external hdparm program. The
 248 *      command can be a drive command, drive task or taskfile 
 249 *      operation. Weirdly you can call it with NULL to wait for
 250 *      all commands to finish. Don't do this as that is due to change
 251 */
 252
 253static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
 254                struct request *rq)
 255{
 256        struct ide_cmd *cmd = rq->special;
 257
 258        if (cmd) {
 259                if (cmd->protocol == ATA_PROT_PIO) {
 260                        ide_init_sg_cmd(cmd, blk_rq_sectors(rq) << 9);
 261                        ide_map_sg(drive, cmd);
 262                }
 263
 264                return do_rw_taskfile(drive, cmd);
 265        }
 266
 267        /*
 268         * NULL is actually a valid way of waiting for
 269         * all current requests to be flushed from the queue.
 270         */
 271#ifdef DEBUG
 272        printk("%s: DRIVE_CMD (null)\n", drive->name);
 273#endif
 274        rq->errors = 0;
 275        ide_complete_rq(drive, 0, blk_rq_bytes(rq));
 276
 277        return ide_stopped;
 278}
 279
 280static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 281{
 282        u8 cmd = rq->cmd[0];
 283
 284        switch (cmd) {
 285        case REQ_PARK_HEADS:
 286        case REQ_UNPARK_HEADS:
 287                return ide_do_park_unpark(drive, rq);
 288        case REQ_DEVSET_EXEC:
 289                return ide_do_devset(drive, rq);
 290        case REQ_DRIVE_RESET:
 291                return ide_do_reset(drive);
 292        default:
 293                BUG();
 294        }
 295}
 296
 297/**
 298 *      start_request   -       start of I/O and command issuing for IDE
 299 *
 300 *      start_request() initiates handling of a new I/O request. It
 301 *      accepts commands and I/O (read/write) requests.
 302 *
 303 *      FIXME: this function needs a rename
 304 */
 305 
 306static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 307{
 308        ide_startstop_t startstop;
 309
 310        BUG_ON(!(rq->cmd_flags & REQ_STARTED));
 311
 312#ifdef DEBUG
 313        printk("%s: start_request: current=0x%08lx\n",
 314                drive->hwif->name, (unsigned long) rq);
 315#endif
 316
 317        /* bail early if we've exceeded max_failures */
 318        if (drive->max_failures && (drive->failures > drive->max_failures)) {
 319                rq->cmd_flags |= REQ_FAILED;
 320                goto kill_rq;
 321        }
 322
 323        if (blk_pm_request(rq))
 324                ide_check_pm_state(drive, rq);
 325
 326        drive->hwif->tp_ops->dev_select(drive);
 327        if (ide_wait_stat(&startstop, drive, drive->ready_stat,
 328                          ATA_BUSY | ATA_DRQ, WAIT_READY)) {
 329                printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 330                return startstop;
 331        }
 332
 333        if (drive->special_flags == 0) {
 334                struct ide_driver *drv;
 335
 336                /*
 337                 * We reset the drive so we need to issue a SETFEATURES.
 338                 * Do it _after_ do_special() restored device parameters.
 339                 */
 340                if (drive->current_speed == 0xff)
 341                        ide_config_drive_speed(drive, drive->desired_speed);
 342
 343                if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
 344                        return execute_drive_cmd(drive, rq);
 345                else if (blk_pm_request(rq)) {
 346                        struct request_pm_state *pm = rq->special;
 347#ifdef DEBUG_PM
 348                        printk("%s: start_power_step(step: %d)\n",
 349                                drive->name, pm->pm_step);
 350#endif
 351                        startstop = ide_start_power_step(drive, rq);
 352                        if (startstop == ide_stopped &&
 353                            pm->pm_step == IDE_PM_COMPLETED)
 354                                ide_complete_pm_rq(drive, rq);
 355                        return startstop;
 356                } else if (!rq->rq_disk && rq->cmd_type == REQ_TYPE_SPECIAL)
 357                        /*
 358                         * TODO: Once all ULDs have been modified to
 359                         * check for specific op codes rather than
 360                         * blindly accepting any special request, the
 361                         * check for ->rq_disk above may be replaced
 362                         * by a more suitable mechanism or even
 363                         * dropped entirely.
 364                         */
 365                        return ide_special_rq(drive, rq);
 366
 367                drv = *(struct ide_driver **)rq->rq_disk->private_data;
 368
 369                return drv->do_request(drive, rq, blk_rq_pos(rq));
 370        }
 371        return do_special(drive);
 372kill_rq:
 373        ide_kill_rq(drive, rq);
 374        return ide_stopped;
 375}
 376
 377/**
 378 *      ide_stall_queue         -       pause an IDE device
 379 *      @drive: drive to stall
 380 *      @timeout: time to stall for (jiffies)
 381 *
 382 *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 383 *      to the port by sleeping for timeout jiffies.
 384 */
 385 
 386void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 387{
 388        if (timeout > WAIT_WORSTCASE)
 389                timeout = WAIT_WORSTCASE;
 390        drive->sleep = timeout + jiffies;
 391        drive->dev_flags |= IDE_DFLAG_SLEEPING;
 392}
 393EXPORT_SYMBOL(ide_stall_queue);
 394
 395static inline int ide_lock_port(ide_hwif_t *hwif)
 396{
 397        if (hwif->busy)
 398                return 1;
 399
 400        hwif->busy = 1;
 401
 402        return 0;
 403}
 404
 405static inline void ide_unlock_port(ide_hwif_t *hwif)
 406{
 407        hwif->busy = 0;
 408}
 409
 410static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
 411{
 412        int rc = 0;
 413
 414        if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 415                rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
 416                if (rc == 0) {
 417                        if (host->get_lock)
 418                                host->get_lock(ide_intr, hwif);
 419                }
 420        }
 421        return rc;
 422}
 423
 424static inline void ide_unlock_host(struct ide_host *host)
 425{
 426        if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 427                if (host->release_lock)
 428                        host->release_lock();
 429                clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
 430        }
 431}
 432
 433static void __ide_requeue_and_plug(struct request_queue *q, struct request *rq)
 434{
 435        if (rq)
 436                blk_requeue_request(q, rq);
 437        if (rq || blk_peek_request(q)) {
 438                /* Use 3ms as that was the old plug delay */
 439                blk_delay_queue(q, 3);
 440        }
 441}
 442
 443void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
 444{
 445        struct request_queue *q = drive->queue;
 446        unsigned long flags;
 447
 448        spin_lock_irqsave(q->queue_lock, flags);
 449        __ide_requeue_and_plug(q, rq);
 450        spin_unlock_irqrestore(q->queue_lock, flags);
 451}
 452
 453/*
 454 * Issue a new request to a device.
 455 */
 456void do_ide_request(struct request_queue *q)
 457{
 458        ide_drive_t     *drive = q->queuedata;
 459        ide_hwif_t      *hwif = drive->hwif;
 460        struct ide_host *host = hwif->host;
 461        struct request  *rq = NULL;
 462        ide_startstop_t startstop;
 463        unsigned long queue_run_ms = 3; /* old plug delay */
 464
 465        spin_unlock_irq(q->queue_lock);
 466
 467        /* HLD do_request() callback might sleep, make sure it's okay */
 468        might_sleep();
 469
 470        if (ide_lock_host(host, hwif))
 471                goto plug_device_2;
 472
 473        spin_lock_irq(&hwif->lock);
 474
 475        if (!ide_lock_port(hwif)) {
 476                ide_hwif_t *prev_port;
 477
 478                WARN_ON_ONCE(hwif->rq);
 479repeat:
 480                prev_port = hwif->host->cur_port;
 481                if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
 482                    time_after(drive->sleep, jiffies)) {
 483                        unsigned long left = jiffies - drive->sleep;
 484
 485                        queue_run_ms = jiffies_to_msecs(left + 1);
 486                        ide_unlock_port(hwif);
 487                        goto plug_device;
 488                }
 489
 490                if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
 491                    hwif != prev_port) {
 492                        ide_drive_t *cur_dev =
 493                                prev_port ? prev_port->cur_dev : NULL;
 494
 495                        /*
 496                         * set nIEN for previous port, drives in the
 497                         * quirk list may not like intr setups/cleanups
 498                         */
 499                        if (cur_dev &&
 500                            (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
 501                                prev_port->tp_ops->write_devctl(prev_port,
 502                                                                ATA_NIEN |
 503                                                                ATA_DEVCTL_OBS);
 504
 505                        hwif->host->cur_port = hwif;
 506                }
 507                hwif->cur_dev = drive;
 508                drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
 509
 510                spin_unlock_irq(&hwif->lock);
 511                spin_lock_irq(q->queue_lock);
 512                /*
 513                 * we know that the queue isn't empty, but this can happen
 514                 * if the q->prep_rq_fn() decides to kill a request
 515                 */
 516                if (!rq)
 517                        rq = blk_fetch_request(drive->queue);
 518
 519                spin_unlock_irq(q->queue_lock);
 520                spin_lock_irq(&hwif->lock);
 521
 522                if (!rq) {
 523                        ide_unlock_port(hwif);
 524                        goto out;
 525                }
 526
 527                /*
 528                 * Sanity: don't accept a request that isn't a PM request
 529                 * if we are currently power managed. This is very important as
 530                 * blk_stop_queue() doesn't prevent the blk_fetch_request()
 531                 * above to return us whatever is in the queue. Since we call
 532                 * ide_do_request() ourselves, we end up taking requests while
 533                 * the queue is blocked...
 534                 * 
 535                 * We let requests forced at head of queue with ide-preempt
 536                 * though. I hope that doesn't happen too much, hopefully not
 537                 * unless the subdriver triggers such a thing in its own PM
 538                 * state machine.
 539                 */
 540                if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
 541                    blk_pm_request(rq) == 0 &&
 542                    (rq->cmd_flags & REQ_PREEMPT) == 0) {
 543                        /* there should be no pending command at this point */
 544                        ide_unlock_port(hwif);
 545                        goto plug_device;
 546                }
 547
 548                hwif->rq = rq;
 549
 550                spin_unlock_irq(&hwif->lock);
 551                startstop = start_request(drive, rq);
 552                spin_lock_irq(&hwif->lock);
 553
 554                if (startstop == ide_stopped) {
 555                        rq = hwif->rq;
 556                        hwif->rq = NULL;
 557                        goto repeat;
 558                }
 559        } else
 560                goto plug_device;
 561out:
 562        spin_unlock_irq(&hwif->lock);
 563        if (rq == NULL)
 564                ide_unlock_host(host);
 565        spin_lock_irq(q->queue_lock);
 566        return;
 567
 568plug_device:
 569        spin_unlock_irq(&hwif->lock);
 570        ide_unlock_host(host);
 571plug_device_2:
 572        spin_lock_irq(q->queue_lock);
 573        __ide_requeue_and_plug(q, rq);
 574}
 575
 576static int drive_is_ready(ide_drive_t *drive)
 577{
 578        ide_hwif_t *hwif = drive->hwif;
 579        u8 stat = 0;
 580
 581        if (drive->waiting_for_dma)
 582                return hwif->dma_ops->dma_test_irq(drive);
 583
 584        if (hwif->io_ports.ctl_addr &&
 585            (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
 586                stat = hwif->tp_ops->read_altstatus(hwif);
 587        else
 588                /* Note: this may clear a pending IRQ!! */
 589                stat = hwif->tp_ops->read_status(hwif);
 590
 591        if (stat & ATA_BUSY)
 592                /* drive busy: definitely not interrupting */
 593                return 0;
 594
 595        /* drive ready: *might* be interrupting */
 596        return 1;
 597}
 598
 599/**
 600 *      ide_timer_expiry        -       handle lack of an IDE interrupt
 601 *      @data: timer callback magic (hwif)
 602 *
 603 *      An IDE command has timed out before the expected drive return
 604 *      occurred. At this point we attempt to clean up the current
 605 *      mess. If the current handler includes an expiry handler then
 606 *      we invoke the expiry handler, and providing it is happy the
 607 *      work is done. If that fails we apply generic recovery rules
 608 *      invoking the handler and checking the drive DMA status. We
 609 *      have an excessively incestuous relationship with the DMA
 610 *      logic that wants cleaning up.
 611 */
 612 
 613void ide_timer_expiry (unsigned long data)
 614{
 615        ide_hwif_t      *hwif = (ide_hwif_t *)data;
 616        ide_drive_t     *uninitialized_var(drive);
 617        ide_handler_t   *handler;
 618        unsigned long   flags;
 619        int             wait = -1;
 620        int             plug_device = 0;
 621        struct request  *uninitialized_var(rq_in_flight);
 622
 623        spin_lock_irqsave(&hwif->lock, flags);
 624
 625        handler = hwif->handler;
 626
 627        if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
 628                /*
 629                 * Either a marginal timeout occurred
 630                 * (got the interrupt just as timer expired),
 631                 * or we were "sleeping" to give other devices a chance.
 632                 * Either way, we don't really want to complain about anything.
 633                 */
 634        } else {
 635                ide_expiry_t *expiry = hwif->expiry;
 636                ide_startstop_t startstop = ide_stopped;
 637
 638                drive = hwif->cur_dev;
 639
 640                if (expiry) {
 641                        wait = expiry(drive);
 642                        if (wait > 0) { /* continue */
 643                                /* reset timer */
 644                                hwif->timer.expires = jiffies + wait;
 645                                hwif->req_gen_timer = hwif->req_gen;
 646                                add_timer(&hwif->timer);
 647                                spin_unlock_irqrestore(&hwif->lock, flags);
 648                                return;
 649                        }
 650                }
 651                hwif->handler = NULL;
 652                hwif->expiry = NULL;
 653                /*
 654                 * We need to simulate a real interrupt when invoking
 655                 * the handler() function, which means we need to
 656                 * globally mask the specific IRQ:
 657                 */
 658                spin_unlock(&hwif->lock);
 659                /* disable_irq_nosync ?? */
 660                disable_irq(hwif->irq);
 661                /* local CPU only, as if we were handling an interrupt */
 662                local_irq_disable();
 663                if (hwif->polling) {
 664                        startstop = handler(drive);
 665                } else if (drive_is_ready(drive)) {
 666                        if (drive->waiting_for_dma)
 667                                hwif->dma_ops->dma_lost_irq(drive);
 668                        if (hwif->port_ops && hwif->port_ops->clear_irq)
 669                                hwif->port_ops->clear_irq(drive);
 670
 671                        printk(KERN_WARNING "%s: lost interrupt\n",
 672                                drive->name);
 673                        startstop = handler(drive);
 674                } else {
 675                        if (drive->waiting_for_dma)
 676                                startstop = ide_dma_timeout_retry(drive, wait);
 677                        else
 678                                startstop = ide_error(drive, "irq timeout",
 679                                        hwif->tp_ops->read_status(hwif));
 680                }
 681                spin_lock_irq(&hwif->lock);
 682                enable_irq(hwif->irq);
 683                if (startstop == ide_stopped && hwif->polling == 0) {
 684                        rq_in_flight = hwif->rq;
 685                        hwif->rq = NULL;
 686                        ide_unlock_port(hwif);
 687                        plug_device = 1;
 688                }
 689        }
 690        spin_unlock_irqrestore(&hwif->lock, flags);
 691
 692        if (plug_device) {
 693                ide_unlock_host(hwif->host);
 694                ide_requeue_and_plug(drive, rq_in_flight);
 695        }
 696}
 697
 698/**
 699 *      unexpected_intr         -       handle an unexpected IDE interrupt
 700 *      @irq: interrupt line
 701 *      @hwif: port being processed
 702 *
 703 *      There's nothing really useful we can do with an unexpected interrupt,
 704 *      other than reading the status register (to clear it), and logging it.
 705 *      There should be no way that an irq can happen before we're ready for it,
 706 *      so we needn't worry much about losing an "important" interrupt here.
 707 *
 708 *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 709 *      the drive enters "idle", "standby", or "sleep" mode, so if the status
 710 *      looks "good", we just ignore the interrupt completely.
 711 *
 712 *      This routine assumes __cli() is in effect when called.
 713 *
 714 *      If an unexpected interrupt happens on irq15 while we are handling irq14
 715 *      and if the two interfaces are "serialized" (CMD640), then it looks like
 716 *      we could screw up by interfering with a new request being set up for 
 717 *      irq15.
 718 *
 719 *      In reality, this is a non-issue.  The new command is not sent unless 
 720 *      the drive is ready to accept one, in which case we know the drive is
 721 *      not trying to interrupt us.  And ide_set_handler() is always invoked
 722 *      before completing the issuance of any new drive command, so we will not
 723 *      be accidentally invoked as a result of any valid command completion
 724 *      interrupt.
 725 */
 726
 727static void unexpected_intr(int irq, ide_hwif_t *hwif)
 728{
 729        u8 stat = hwif->tp_ops->read_status(hwif);
 730
 731        if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
 732                /* Try to not flood the console with msgs */
 733                static unsigned long last_msgtime, count;
 734                ++count;
 735
 736                if (time_after(jiffies, last_msgtime + HZ)) {
 737                        last_msgtime = jiffies;
 738                        printk(KERN_ERR "%s: unexpected interrupt, "
 739                                "status=0x%02x, count=%ld\n",
 740                                hwif->name, stat, count);
 741                }
 742        }
 743}
 744
 745/**
 746 *      ide_intr        -       default IDE interrupt handler
 747 *      @irq: interrupt number
 748 *      @dev_id: hwif
 749 *      @regs: unused weirdness from the kernel irq layer
 750 *
 751 *      This is the default IRQ handler for the IDE layer. You should
 752 *      not need to override it. If you do be aware it is subtle in
 753 *      places
 754 *
 755 *      hwif is the interface in the group currently performing
 756 *      a command. hwif->cur_dev is the drive and hwif->handler is
 757 *      the IRQ handler to call. As we issue a command the handlers
 758 *      step through multiple states, reassigning the handler to the
 759 *      next step in the process. Unlike a smart SCSI controller IDE
 760 *      expects the main processor to sequence the various transfer
 761 *      stages. We also manage a poll timer to catch up with most
 762 *      timeout situations. There are still a few where the handlers
 763 *      don't ever decide to give up.
 764 *
 765 *      The handler eventually returns ide_stopped to indicate the
 766 *      request completed. At this point we issue the next request
 767 *      on the port and the process begins again.
 768 */
 769
 770irqreturn_t ide_intr (int irq, void *dev_id)
 771{
 772        ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
 773        struct ide_host *host = hwif->host;
 774        ide_drive_t *uninitialized_var(drive);
 775        ide_handler_t *handler;
 776        unsigned long flags;
 777        ide_startstop_t startstop;
 778        irqreturn_t irq_ret = IRQ_NONE;
 779        int plug_device = 0;
 780        struct request *uninitialized_var(rq_in_flight);
 781
 782        if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 783                if (hwif != host->cur_port)
 784                        goto out_early;
 785        }
 786
 787        spin_lock_irqsave(&hwif->lock, flags);
 788
 789        if (hwif->port_ops && hwif->port_ops->test_irq &&
 790            hwif->port_ops->test_irq(hwif) == 0)
 791                goto out;
 792
 793        handler = hwif->handler;
 794
 795        if (handler == NULL || hwif->polling) {
 796                /*
 797                 * Not expecting an interrupt from this drive.
 798                 * That means this could be:
 799                 *      (1) an interrupt from another PCI device
 800                 *      sharing the same PCI INT# as us.
 801                 * or   (2) a drive just entered sleep or standby mode,
 802                 *      and is interrupting to let us know.
 803                 * or   (3) a spurious interrupt of unknown origin.
 804                 *
 805                 * For PCI, we cannot tell the difference,
 806                 * so in that case we just ignore it and hope it goes away.
 807                 */
 808                if ((host->irq_flags & IRQF_SHARED) == 0) {
 809                        /*
 810                         * Probably not a shared PCI interrupt,
 811                         * so we can safely try to do something about it:
 812                         */
 813                        unexpected_intr(irq, hwif);
 814                } else {
 815                        /*
 816                         * Whack the status register, just in case
 817                         * we have a leftover pending IRQ.
 818                         */
 819                        (void)hwif->tp_ops->read_status(hwif);
 820                }
 821                goto out;
 822        }
 823
 824        drive = hwif->cur_dev;
 825
 826        if (!drive_is_ready(drive))
 827                /*
 828                 * This happens regularly when we share a PCI IRQ with
 829                 * another device.  Unfortunately, it can also happen
 830                 * with some buggy drives that trigger the IRQ before
 831                 * their status register is up to date.  Hopefully we have
 832                 * enough advance overhead that the latter isn't a problem.
 833                 */
 834                goto out;
 835
 836        hwif->handler = NULL;
 837        hwif->expiry = NULL;
 838        hwif->req_gen++;
 839        del_timer(&hwif->timer);
 840        spin_unlock(&hwif->lock);
 841
 842        if (hwif->port_ops && hwif->port_ops->clear_irq)
 843                hwif->port_ops->clear_irq(drive);
 844
 845        if (drive->dev_flags & IDE_DFLAG_UNMASK)
 846                local_irq_enable_in_hardirq();
 847
 848        /* service this interrupt, may set handler for next interrupt */
 849        startstop = handler(drive);
 850
 851        spin_lock_irq(&hwif->lock);
 852        /*
 853         * Note that handler() may have set things up for another
 854         * interrupt to occur soon, but it cannot happen until
 855         * we exit from this routine, because it will be the
 856         * same irq as is currently being serviced here, and Linux
 857         * won't allow another of the same (on any CPU) until we return.
 858         */
 859        if (startstop == ide_stopped && hwif->polling == 0) {
 860                BUG_ON(hwif->handler);
 861                rq_in_flight = hwif->rq;
 862                hwif->rq = NULL;
 863                ide_unlock_port(hwif);
 864                plug_device = 1;
 865        }
 866        irq_ret = IRQ_HANDLED;
 867out:
 868        spin_unlock_irqrestore(&hwif->lock, flags);
 869out_early:
 870        if (plug_device) {
 871                ide_unlock_host(hwif->host);
 872                ide_requeue_and_plug(drive, rq_in_flight);
 873        }
 874
 875        return irq_ret;
 876}
 877EXPORT_SYMBOL_GPL(ide_intr);
 878
 879void ide_pad_transfer(ide_drive_t *drive, int write, int len)
 880{
 881        ide_hwif_t *hwif = drive->hwif;
 882        u8 buf[4] = { 0 };
 883
 884        while (len > 0) {
 885                if (write)
 886                        hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
 887                else
 888                        hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
 889                len -= 4;
 890        }
 891}
 892EXPORT_SYMBOL_GPL(ide_pad_transfer);
 893
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