drivers/ide/ide-io.c

   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 <linux/uaccess.h>
  55 #include <asm/io.h>
  56
  57 int ide_end_rq(ide_drive_t *drive, struct request *rq, blk_status_t 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         if (!blk_update_request(rq, error, nr_bytes)) {
  71                 if (rq == drive->sense_rq) {
  72                         drive->sense_rq = NULL;
  73                         drive->sense_rq_active = false;
  74                 }
  75
  76                 __blk_mq_end_request(rq, error);
  77                 return 0;
  78         }
  79
  80         return 1;
  81 }
  82 EXPORT_SYMBOL_GPL(ide_end_rq);
  83
  84 void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err)
  85 {
  86         const struct ide_tp_ops *tp_ops = drive->hwif->tp_ops;
  87         struct ide_taskfile *tf = &cmd->tf;
  88         struct request *rq = cmd->rq;
  89         u8 tf_cmd = tf->command;
  90
  91         tf->error = err;
  92         tf->status = stat;
  93
  94         if (cmd->ftf_flags & IDE_FTFLAG_IN_DATA) {
  95                 u8 data[2];
  96
  97                 tp_ops->input_data(drive, cmd, data, 2);
  98
  99                 cmd->tf.data  = data[0];
 100                 cmd->hob.data = data[1];
 101         }
 102
 103         ide_tf_readback(drive, cmd);
 104
 105         if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) &&
 106             tf_cmd == ATA_CMD_IDLEIMMEDIATE) {
 107                 if (tf->lbal != 0xc4) {
 108                         printk(KERN_ERR "%s: head unload failed!\n",
 109                                drive->name);
 110                         ide_tf_dump(drive->name, cmd);
 111                 } else
 112                         drive->dev_flags |= IDE_DFLAG_PARKED;
 113         }
 114
 115         if (rq && ata_taskfile_request(rq)) {
 116                 struct ide_cmd *orig_cmd = ide_req(rq)->special;
 117
 118                 if (cmd->tf_flags & IDE_TFLAG_DYN)
 119                         kfree(orig_cmd);
 120                 else if (cmd != orig_cmd)
 121                         memcpy(orig_cmd, cmd, sizeof(*cmd));
 122         }
 123 }
 124
 125 int ide_complete_rq(ide_drive_t *drive, blk_status_t error, unsigned int nr_bytes)
 126 {
 127         ide_hwif_t *hwif = drive->hwif;
 128         struct request *rq = hwif->rq;
 129         int rc;
 130
 131         /*
 132          * if failfast is set on a request, override number of sectors
 133          * and complete the whole request right now
 134          */
 135         if (blk_noretry_request(rq) && error)
 136                 nr_bytes = blk_rq_sectors(rq) << 9;
 137
 138         rc = ide_end_rq(drive, rq, error, nr_bytes);
 139         if (rc == 0)
 140                 hwif->rq = NULL;
 141
 142         return rc;
 143 }
 144 EXPORT_SYMBOL(ide_complete_rq);
 145
 146 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
 147 {
 148         u8 drv_req = ata_misc_request(rq) && rq->rq_disk;
 149         u8 media = drive->media;
 150
 151         drive->failed_pc = NULL;
 152
 153         if ((media == ide_floppy || media == ide_tape) && drv_req) {
 154                 scsi_req(rq)->result = 0;
 155         } else {
 156                 if (media == ide_tape)
 157                         scsi_req(rq)->result = IDE_DRV_ERROR_GENERAL;
 158                 else if (blk_rq_is_passthrough(rq) && scsi_req(rq)->result == 0)
 159                         scsi_req(rq)->result = -EIO;
 160         }
 161
 162         ide_complete_rq(drive, BLK_STS_IOERR, blk_rq_bytes(rq));
 163 }
 164
 165 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 166 {
 167         tf->nsect   = drive->sect;
 168         tf->lbal    = drive->sect;
 169         tf->lbam    = drive->cyl;
 170         tf->lbah    = drive->cyl >> 8;
 171         tf->device  = (drive->head - 1) | drive->select;
 172         tf->command = ATA_CMD_INIT_DEV_PARAMS;
 173 }
 174
 175 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 176 {
 177         tf->nsect   = drive->sect;
 178         tf->command = ATA_CMD_RESTORE;
 179 }
 180
 181 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 182 {
 183         tf->nsect   = drive->mult_req;
 184         tf->command = ATA_CMD_SET_MULTI;
 185 }
 186
 187 /**
 188  *      do_special              -       issue some special commands
 189  *      @drive: drive the command is for
 190  *
 191  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
 192  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
 193  */
 194
 195 static ide_startstop_t do_special(ide_drive_t *drive)
 196 {
 197         struct ide_cmd cmd;
 198
 199 #ifdef DEBUG
 200         printk(KERN_DEBUG "%s: %s: 0x%02x\n", drive->name, __func__,
 201                 drive->special_flags);
 202 #endif
 203         if (drive->media != ide_disk) {
 204                 drive->special_flags = 0;
 205                 drive->mult_req = 0;
 206                 return ide_stopped;
 207         }
 208
 209         memset(&cmd, 0, sizeof(cmd));
 210         cmd.protocol = ATA_PROT_NODATA;
 211
 212         if (drive->special_flags & IDE_SFLAG_SET_GEOMETRY) {
 213                 drive->special_flags &= ~IDE_SFLAG_SET_GEOMETRY;
 214                 ide_tf_set_specify_cmd(drive, &cmd.tf);
 215         } else if (drive->special_flags & IDE_SFLAG_RECALIBRATE) {
 216                 drive->special_flags &= ~IDE_SFLAG_RECALIBRATE;
 217                 ide_tf_set_restore_cmd(drive, &cmd.tf);
 218         } else if (drive->special_flags & IDE_SFLAG_SET_MULTMODE) {
 219                 drive->special_flags &= ~IDE_SFLAG_SET_MULTMODE;
 220                 ide_tf_set_setmult_cmd(drive, &cmd.tf);
 221         } else
 222                 BUG();
 223
 224         cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
 225         cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
 226         cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER;
 227
 228         do_rw_taskfile(drive, &cmd);
 229
 230         return ide_started;
 231 }
 232
 233 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
 234 {
 235         ide_hwif_t *hwif = drive->hwif;
 236         struct scatterlist *sg = hwif->sg_table, *last_sg = NULL;
 237         struct request *rq = cmd->rq;
 238
 239         cmd->sg_nents = __blk_rq_map_sg(drive->queue, rq, sg, &last_sg);
 240         if (blk_rq_bytes(rq) && (blk_rq_bytes(rq) & rq->q->dma_pad_mask))
 241                 last_sg->length +=
 242                         (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
 243 }
 244 EXPORT_SYMBOL_GPL(ide_map_sg);
 245
 246 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
 247 {
 248         cmd->nbytes = cmd->nleft = nr_bytes;
 249         cmd->cursg_ofs = 0;
 250         cmd->cursg = NULL;
 251 }
 252 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 253
 254 /**
 255  *      execute_drive_command   -       issue special drive command
 256  *      @drive: the drive to issue the command on
 257  *      @rq: the request structure holding the command
 258  *
 259  *      execute_drive_cmd() issues a special drive command,  usually
 260  *      initiated by ioctl() from the external hdparm program. The
 261  *      command can be a drive command, drive task or taskfile
 262  *      operation. Weirdly you can call it with NULL to wait for
 263  *      all commands to finish. Don't do this as that is due to change
 264  */
 265
 266 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
 267                 struct request *rq)
 268 {
 269         struct ide_cmd *cmd = ide_req(rq)->special;
 270
 271         if (cmd) {
 272                 if (cmd->protocol == ATA_PROT_PIO) {
 273                         ide_init_sg_cmd(cmd, blk_rq_sectors(rq) << 9);
 274                         ide_map_sg(drive, cmd);
 275                 }
 276
 277                 return do_rw_taskfile(drive, cmd);
 278         }
 279
 280         /*
 281          * NULL is actually a valid way of waiting for
 282          * all current requests to be flushed from the queue.
 283          */
 284 #ifdef DEBUG
 285         printk("%s: DRIVE_CMD (null)\n", drive->name);
 286 #endif
 287         scsi_req(rq)->result = 0;
 288         ide_complete_rq(drive, BLK_STS_OK, blk_rq_bytes(rq));
 289
 290         return ide_stopped;
 291 }
 292
 293 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 294 {
 295         u8 cmd = scsi_req(rq)->cmd[0];
 296
 297         switch (cmd) {
 298         case REQ_PARK_HEADS:
 299         case REQ_UNPARK_HEADS:
 300                 return ide_do_park_unpark(drive, rq);
 301         case REQ_DEVSET_EXEC:
 302                 return ide_do_devset(drive, rq);
 303         case REQ_DRIVE_RESET:
 304                 return ide_do_reset(drive);
 305         default:
 306                 BUG();
 307         }
 308 }
 309
 310 /**
 311  *      start_request   -       start of I/O and command issuing for IDE
 312  *
 313  *      start_request() initiates handling of a new I/O request. It
 314  *      accepts commands and I/O (read/write) requests.
 315  *
 316  *      FIXME: this function needs a rename
 317  */
 318
 319 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 320 {
 321         ide_startstop_t startstop;
 322
 323 #ifdef DEBUG
 324         printk("%s: start_request: current=0x%08lx\n",
 325                 drive->hwif->name, (unsigned long) rq);
 326 #endif
 327
 328         /* bail early if we've exceeded max_failures */
 329         if (drive->max_failures && (drive->failures > drive->max_failures)) {
 330                 rq->rq_flags |= RQF_FAILED;
 331                 goto kill_rq;
 332         }
 333
 334         if (drive->prep_rq && !drive->prep_rq(drive, rq))
 335                 return ide_stopped;
 336
 337         if (ata_pm_request(rq))
 338                 ide_check_pm_state(drive, rq);
 339
 340         drive->hwif->tp_ops->dev_select(drive);
 341         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
 342                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
 343                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 344                 return startstop;
 345         }
 346
 347         if (drive->special_flags == 0) {
 348                 struct ide_driver *drv;
 349
 350                 /*
 351                  * We reset the drive so we need to issue a SETFEATURES.
 352                  * Do it _after_ do_special() restored device parameters.
 353                  */
 354                 if (drive->current_speed == 0xff)
 355                         ide_config_drive_speed(drive, drive->desired_speed);
 356
 357                 if (ata_taskfile_request(rq))
 358                         return execute_drive_cmd(drive, rq);
 359                 else if (ata_pm_request(rq)) {
 360                         struct ide_pm_state *pm = ide_req(rq)->special;
 361 #ifdef DEBUG_PM
 362                         printk("%s: start_power_step(step: %d)\n",
 363                                 drive->name, pm->pm_step);
 364 #endif
 365                         startstop = ide_start_power_step(drive, rq);
 366                         if (startstop == ide_stopped &&
 367                             pm->pm_step == IDE_PM_COMPLETED)
 368                                 ide_complete_pm_rq(drive, rq);
 369                         return startstop;
 370                 } else if (!rq->rq_disk && ata_misc_request(rq))
 371                         /*
 372                          * TODO: Once all ULDs have been modified to
 373                          * check for specific op codes rather than
 374                          * blindly accepting any special request, the
 375                          * check for ->rq_disk above may be replaced
 376                          * by a more suitable mechanism or even
 377                          * dropped entirely.
 378                          */
 379                         return ide_special_rq(drive, rq);
 380
 381                 drv = *(struct ide_driver **)rq->rq_disk->private_data;
 382
 383                 return drv->do_request(drive, rq, blk_rq_pos(rq));
 384         }
 385         return do_special(drive);
 386 kill_rq:
 387         ide_kill_rq(drive, rq);
 388         return ide_stopped;
 389 }
 390
 391 /**
 392  *      ide_stall_queue         -       pause an IDE device
 393  *      @drive: drive to stall
 394  *      @timeout: time to stall for (jiffies)
 395  *
 396  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 397  *      to the port by sleeping for timeout jiffies.
 398  */
 399
 400 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 401 {
 402         if (timeout > WAIT_WORSTCASE)
 403                 timeout = WAIT_WORSTCASE;
 404         drive->sleep = timeout + jiffies;
 405         drive->dev_flags |= IDE_DFLAG_SLEEPING;
 406 }
 407 EXPORT_SYMBOL(ide_stall_queue);
 408
 409 static inline int ide_lock_port(ide_hwif_t *hwif)
 410 {
 411         if (hwif->busy)
 412                 return 1;
 413
 414         hwif->busy = 1;
 415
 416         return 0;
 417 }
 418
 419 static inline void ide_unlock_port(ide_hwif_t *hwif)
 420 {
 421         hwif->busy = 0;
 422 }
 423
 424 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
 425 {
 426         int rc = 0;
 427
 428         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 429                 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
 430                 if (rc == 0) {
 431                         if (host->get_lock)
 432                                 host->get_lock(ide_intr, hwif);
 433                 }
 434         }
 435         return rc;
 436 }
 437
 438 static inline void ide_unlock_host(struct ide_host *host)
 439 {
 440         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 441                 if (host->release_lock)
 442                         host->release_lock();
 443                 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
 444         }
 445 }
 446
 447 void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
 448 {
 449         struct request_queue *q = drive->queue;
 450
 451         /* Use 3ms as that was the old plug delay */
 452         if (rq) {
 453                 blk_mq_requeue_request(rq, false);
 454                 blk_mq_delay_kick_requeue_list(q, 3);
 455         } else
 456                 blk_mq_delay_run_hw_queue(q->queue_hw_ctx[0], 3);
 457 }
 458
 459 blk_status_t ide_issue_rq(ide_drive_t *drive, struct request *rq,
 460                           bool local_requeue)
 461 {
 462         ide_hwif_t *hwif = drive->hwif;
 463         struct ide_host *host = hwif->host;
 464         ide_startstop_t startstop;
 465
 466         if (!blk_rq_is_passthrough(rq) && !(rq->rq_flags & RQF_DONTPREP)) {
 467                 rq->rq_flags |= RQF_DONTPREP;
 468                 ide_req(rq)->special = NULL;
 469         }
 470
 471         /* HLD do_request() callback might sleep, make sure it's okay */
 472         might_sleep();
 473
 474         if (ide_lock_host(host, hwif))
 475                 return BLK_STS_DEV_RESOURCE;
 476
 477         spin_lock_irq(&hwif->lock);
 478
 479         if (!ide_lock_port(hwif)) {
 480                 ide_hwif_t *prev_port;
 481
 482                 WARN_ON_ONCE(hwif->rq);
 483 repeat:
 484                 prev_port = hwif->host->cur_port;
 485                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
 486                     time_after(drive->sleep, jiffies)) {
 487                         ide_unlock_port(hwif);
 488                         goto plug_device;
 489                 }
 490
 491                 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
 492                     hwif != prev_port) {
 493                         ide_drive_t *cur_dev =
 494                                 prev_port ? prev_port->cur_dev : NULL;
 495
 496                         /*
 497                          * set nIEN for previous port, drives in the
 498                          * quirk list may not like intr setups/cleanups
 499                          */
 500                         if (cur_dev &&
 501                             (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
 502                                 prev_port->tp_ops->write_devctl(prev_port,
 503                                                                 ATA_NIEN |
 504                                                                 ATA_DEVCTL_OBS);
 505
 506                         hwif->host->cur_port = hwif;
 507                 }
 508                 hwif->cur_dev = drive;
 509                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
 510
 511                 /*
 512                  * Sanity: don't accept a request that isn't a PM request
 513                  * if we are currently power managed. This is very important as
 514                  * blk_stop_queue() doesn't prevent the blk_fetch_request()
 515                  * above to return us whatever is in the queue. Since we call
 516                  * ide_do_request() ourselves, we end up taking requests while
 517                  * the queue is blocked...
 518                  *
 519                  * We let requests forced at head of queue with ide-preempt
 520                  * though. I hope that doesn't happen too much, hopefully not
 521                  * unless the subdriver triggers such a thing in its own PM
 522                  * state machine.
 523                  */
 524                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
 525                     ata_pm_request(rq) == 0 &&
 526                     (rq->rq_flags & RQF_PREEMPT) == 0) {
 527                         /* there should be no pending command at this point */
 528                         ide_unlock_port(hwif);
 529                         goto plug_device;
 530                 }
 531
 532                 scsi_req(rq)->resid_len = blk_rq_bytes(rq);
 533                 hwif->rq = rq;
 534
 535                 spin_unlock_irq(&hwif->lock);
 536                 startstop = start_request(drive, rq);
 537                 spin_lock_irq(&hwif->lock);
 538
 539                 if (startstop == ide_stopped) {
 540                         rq = hwif->rq;
 541                         hwif->rq = NULL;
 542                         if (rq)
 543                                 goto repeat;
 544                         ide_unlock_port(hwif);
 545                         goto out;
 546                 }
 547         } else {
 548 plug_device:
 549                 if (local_requeue)
 550                         list_add(&rq->queuelist, &drive->rq_list);
 551                 spin_unlock_irq(&hwif->lock);
 552                 ide_unlock_host(host);
 553                 if (!local_requeue)
 554                         ide_requeue_and_plug(drive, rq);
 555                 return BLK_STS_OK;
 556         }
 557
 558 out:
 559         spin_unlock_irq(&hwif->lock);
 560         if (rq == NULL)
 561                 ide_unlock_host(host);
 562         return BLK_STS_OK;
 563 }
 564
 565 /*
 566  * Issue a new request to a device.
 567  */
 568 blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
 569                           const struct blk_mq_queue_data *bd)
 570 {
 571         ide_drive_t *drive = hctx->queue->queuedata;
 572         ide_hwif_t *hwif = drive->hwif;
 573
 574         spin_lock_irq(&hwif->lock);
 575         if (drive->sense_rq_active) {
 576                 spin_unlock_irq(&hwif->lock);
 577                 return BLK_STS_DEV_RESOURCE;
 578         }
 579         spin_unlock_irq(&hwif->lock);
 580
 581         blk_mq_start_request(bd->rq);
 582         return ide_issue_rq(drive, bd->rq, false);
 583 }
 584
 585 static int drive_is_ready(ide_drive_t *drive)
 586 {
 587         ide_hwif_t *hwif = drive->hwif;
 588         u8 stat = 0;
 589
 590         if (drive->waiting_for_dma)
 591                 return hwif->dma_ops->dma_test_irq(drive);
 592
 593         if (hwif->io_ports.ctl_addr &&
 594             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
 595                 stat = hwif->tp_ops->read_altstatus(hwif);
 596         else
 597                 /* Note: this may clear a pending IRQ!! */
 598                 stat = hwif->tp_ops->read_status(hwif);
 599
 600         if (stat & ATA_BUSY)
 601                 /* drive busy: definitely not interrupting */
 602                 return 0;
 603
 604         /* drive ready: *might* be interrupting */
 605         return 1;
 606 }
 607
 608 /**
 609  *      ide_timer_expiry        -       handle lack of an IDE interrupt
 610  *      @data: timer callback magic (hwif)
 611  *
 612  *      An IDE command has timed out before the expected drive return
 613  *      occurred. At this point we attempt to clean up the current
 614  *      mess. If the current handler includes an expiry handler then
 615  *      we invoke the expiry handler, and providing it is happy the
 616  *      work is done. If that fails we apply generic recovery rules
 617  *      invoking the handler and checking the drive DMA status. We
 618  *      have an excessively incestuous relationship with the DMA
 619  *      logic that wants cleaning up.
 620  */
 621
 622 void ide_timer_expiry (struct timer_list *t)
 623 {
 624         ide_hwif_t      *hwif = from_timer(hwif, t, timer);
 625         ide_drive_t     *drive;
 626         ide_handler_t   *handler;
 627         unsigned long   flags;
 628         int             wait = -1;
 629         int             plug_device = 0;
 630         struct request  *rq_in_flight;
 631
 632         spin_lock_irqsave(&hwif->lock, flags);
 633
 634         handler = hwif->handler;
 635
 636         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
 637                 /*
 638                  * Either a marginal timeout occurred
 639                  * (got the interrupt just as timer expired),
 640                  * or we were "sleeping" to give other devices a chance.
 641                  * Either way, we don't really want to complain about anything.
 642                  */
 643         } else {
 644                 ide_expiry_t *expiry = hwif->expiry;
 645                 ide_startstop_t startstop = ide_stopped;
 646
 647                 drive = hwif->cur_dev;
 648
 649                 if (expiry) {
 650                         wait = expiry(drive);
 651                         if (wait > 0) { /* continue */
 652                                 /* reset timer */
 653                                 hwif->timer.expires = jiffies + wait;
 654                                 hwif->req_gen_timer = hwif->req_gen;
 655                                 add_timer(&hwif->timer);
 656                                 spin_unlock_irqrestore(&hwif->lock, flags);
 657                                 return;
 658                         }
 659                 }
 660                 hwif->handler = NULL;
 661                 hwif->expiry = NULL;
 662                 /*
 663                  * We need to simulate a real interrupt when invoking
 664                  * the handler() function, which means we need to
 665                  * globally mask the specific IRQ:
 666                  */
 667                 spin_unlock(&hwif->lock);
 668                 /* disable_irq_nosync ?? */
 669                 disable_irq(hwif->irq);
 670
 671                 if (hwif->polling) {
 672                         startstop = handler(drive);
 673                 } else if (drive_is_ready(drive)) {
 674                         if (drive->waiting_for_dma)
 675                                 hwif->dma_ops->dma_lost_irq(drive);
 676                         if (hwif->port_ops && hwif->port_ops->clear_irq)
 677                                 hwif->port_ops->clear_irq(drive);
 678
 679                         printk(KERN_WARNING "%s: lost interrupt\n",
 680                                 drive->name);
 681                         startstop = handler(drive);
 682                 } else {
 683                         if (drive->waiting_for_dma)
 684                                 startstop = ide_dma_timeout_retry(drive, wait);
 685                         else
 686                                 startstop = ide_error(drive, "irq timeout",
 687                                         hwif->tp_ops->read_status(hwif));
 688                 }
 689                 /* Disable interrupts again, `handler' might have enabled it */
 690                 spin_lock_irq(&hwif->lock);
 691                 enable_irq(hwif->irq);
 692                 if (startstop == ide_stopped && hwif->polling == 0) {
 693                         rq_in_flight = hwif->rq;
 694                         hwif->rq = NULL;
 695                         ide_unlock_port(hwif);
 696                         plug_device = 1;
 697                 }
 698         }
 699         spin_unlock_irqrestore(&hwif->lock, flags);
 700
 701         if (plug_device) {
 702                 ide_unlock_host(hwif->host);
 703                 ide_requeue_and_plug(drive, rq_in_flight);
 704         }
 705 }
 706
 707 /**
 708  *      unexpected_intr         -       handle an unexpected IDE interrupt
 709  *      @irq: interrupt line
 710  *      @hwif: port being processed
 711  *
 712  *      There's nothing really useful we can do with an unexpected interrupt,
 713  *      other than reading the status register (to clear it), and logging it.
 714  *      There should be no way that an irq can happen before we're ready for it,
 715  *      so we needn't worry much about losing an "important" interrupt here.
 716  *
 717  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 718  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
 719  *      looks "good", we just ignore the interrupt completely.
 720  *
 721  *      This routine assumes __cli() is in effect when called.
 722  *
 723  *      If an unexpected interrupt happens on irq15 while we are handling irq14
 724  *      and if the two interfaces are "serialized" (CMD640), then it looks like
 725  *      we could screw up by interfering with a new request being set up for
 726  *      irq15.
 727  *
 728  *      In reality, this is a non-issue.  The new command is not sent unless
 729  *      the drive is ready to accept one, in which case we know the drive is
 730  *      not trying to interrupt us.  And ide_set_handler() is always invoked
 731  *      before completing the issuance of any new drive command, so we will not
 732  *      be accidentally invoked as a result of any valid command completion
 733  *      interrupt.
 734  */
 735
 736 static void unexpected_intr(int irq, ide_hwif_t *hwif)
 737 {
 738         u8 stat = hwif->tp_ops->read_status(hwif);
 739
 740         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
 741                 /* Try to not flood the console with msgs */
 742                 static unsigned long last_msgtime, count;
 743                 ++count;
 744
 745                 if (time_after(jiffies, last_msgtime + HZ)) {
 746                         last_msgtime = jiffies;
 747                         printk(KERN_ERR "%s: unexpected interrupt, "
 748                                 "status=0x%02x, count=%ld\n",
 749                                 hwif->name, stat, count);
 750                 }
 751         }
 752 }
 753
 754 /**
 755  *      ide_intr        -       default IDE interrupt handler
 756  *      @irq: interrupt number
 757  *      @dev_id: hwif
 758  *      @regs: unused weirdness from the kernel irq layer
 759  *
 760  *      This is the default IRQ handler for the IDE layer. You should
 761  *      not need to override it. If you do be aware it is subtle in
 762  *      places
 763  *
 764  *      hwif is the interface in the group currently performing
 765  *      a command. hwif->cur_dev is the drive and hwif->handler is
 766  *      the IRQ handler to call. As we issue a command the handlers
 767  *      step through multiple states, reassigning the handler to the
 768  *      next step in the process. Unlike a smart SCSI controller IDE
 769  *      expects the main processor to sequence the various transfer
 770  *      stages. We also manage a poll timer to catch up with most
 771  *      timeout situations. There are still a few where the handlers
 772  *      don't ever decide to give up.
 773  *
 774  *      The handler eventually returns ide_stopped to indicate the
 775  *      request completed. At this point we issue the next request
 776  *      on the port and the process begins again.
 777  */
 778
 779 irqreturn_t ide_intr (int irq, void *dev_id)
 780 {
 781         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
 782         struct ide_host *host = hwif->host;
 783         ide_drive_t *drive;
 784         ide_handler_t *handler;
 785         unsigned long flags;
 786         ide_startstop_t startstop;
 787         irqreturn_t irq_ret = IRQ_NONE;
 788         int plug_device = 0;
 789         struct request *rq_in_flight;
 790
 791         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 792                 if (hwif != host->cur_port)
 793                         goto out_early;
 794         }
 795
 796         spin_lock_irqsave(&hwif->lock, flags);
 797
 798         if (hwif->port_ops && hwif->port_ops->test_irq &&
 799             hwif->port_ops->test_irq(hwif) == 0)
 800                 goto out;
 801
 802         handler = hwif->handler;
 803
 804         if (handler == NULL || hwif->polling) {
 805                 /*
 806                  * Not expecting an interrupt from this drive.
 807                  * That means this could be:
 808                  *      (1) an interrupt from another PCI device
 809                  *      sharing the same PCI INT# as us.
 810                  * or   (2) a drive just entered sleep or standby mode,
 811                  *      and is interrupting to let us know.
 812                  * or   (3) a spurious interrupt of unknown origin.
 813                  *
 814                  * For PCI, we cannot tell the difference,
 815                  * so in that case we just ignore it and hope it goes away.
 816                  */
 817                 if ((host->irq_flags & IRQF_SHARED) == 0) {
 818                         /*
 819                          * Probably not a shared PCI interrupt,
 820                          * so we can safely try to do something about it:
 821                          */
 822                         unexpected_intr(irq, hwif);
 823                 } else {
 824                         /*
 825                          * Whack the status register, just in case
 826                          * we have a leftover pending IRQ.
 827                          */
 828                         (void)hwif->tp_ops->read_status(hwif);
 829                 }
 830                 goto out;
 831         }
 832
 833         drive = hwif->cur_dev;
 834
 835         if (!drive_is_ready(drive))
 836                 /*
 837                  * This happens regularly when we share a PCI IRQ with
 838                  * another device.  Unfortunately, it can also happen
 839                  * with some buggy drives that trigger the IRQ before
 840                  * their status register is up to date.  Hopefully we have
 841                  * enough advance overhead that the latter isn't a problem.
 842                  */
 843                 goto out;
 844
 845         hwif->handler = NULL;
 846         hwif->expiry = NULL;
 847         hwif->req_gen++;
 848         del_timer(&hwif->timer);
 849         spin_unlock(&hwif->lock);
 850
 851         if (hwif->port_ops && hwif->port_ops->clear_irq)
 852                 hwif->port_ops->clear_irq(drive);
 853
 854         if (drive->dev_flags & IDE_DFLAG_UNMASK)
 855                 local_irq_enable_in_hardirq();
 856
 857         /* service this interrupt, may set handler for next interrupt */
 858         startstop = handler(drive);
 859
 860         spin_lock_irq(&hwif->lock);
 861         /*
 862          * Note that handler() may have set things up for another
 863          * interrupt to occur soon, but it cannot happen until
 864          * we exit from this routine, because it will be the
 865          * same irq as is currently being serviced here, and Linux
 866          * won't allow another of the same (on any CPU) until we return.
 867          */
 868         if (startstop == ide_stopped && hwif->polling == 0) {
 869                 BUG_ON(hwif->handler);
 870                 rq_in_flight = hwif->rq;
 871                 hwif->rq = NULL;
 872                 ide_unlock_port(hwif);
 873                 plug_device = 1;
 874         }
 875         irq_ret = IRQ_HANDLED;
 876 out:
 877         spin_unlock_irqrestore(&hwif->lock, flags);
 878 out_early:
 879         if (plug_device) {
 880                 ide_unlock_host(hwif->host);
 881                 ide_requeue_and_plug(drive, rq_in_flight);
 882         }
 883
 884         return irq_ret;
 885 }
 886 EXPORT_SYMBOL_GPL(ide_intr);
 887
 888 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
 889 {
 890         ide_hwif_t *hwif = drive->hwif;
 891         u8 buf[4] = { 0 };
 892
 893         while (len > 0) {
 894                 if (write)
 895                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
 896                 else
 897                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
 898                 len -= 4;
 899         }
 900 }
 901 EXPORT_SYMBOL_GPL(ide_pad_transfer);
 902
 903 void ide_insert_request_head(ide_drive_t *drive, struct request *rq)
 904 {
 905         drive->sense_rq_active = true;
 906         list_add_tail(&rq->queuelist, &drive->rq_list);
 907         kblockd_schedule_work(&drive->rq_work);
 908 }
 909 EXPORT_SYMBOL_GPL(ide_insert_request_head);