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 <asm/uaccess.h>
  55 #include <asm/io.h>
  56
  57 int 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 }
  72 EXPORT_SYMBOL_GPL(ide_end_rq);
  73
  74 void 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
 115 /* obsolete, blk_rq_bytes() should be used instead */
 116 unsigned int ide_rq_bytes(struct request *rq)
 117 {
 118         if (blk_pc_request(rq))
 119                 return rq->data_len;
 120         else
 121                 return rq->hard_cur_sectors << 9;
 122 }
 123 EXPORT_SYMBOL_GPL(ide_rq_bytes);
 124
 125 int ide_complete_rq(ide_drive_t *drive, int 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 <= 0)
 136                 nr_bytes = rq->hard_nr_sectors << 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 = blk_special_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                 rq->errors = 0;
 155                 ide_complete_rq(drive, 0, blk_rq_bytes(rq));
 156         } else {
 157                 if (media == ide_tape)
 158                         rq->errors = IDE_DRV_ERROR_GENERAL;
 159                 else if (blk_fs_request(rq) == 0 && rq->errors == 0)
 160                         rq->errors = -EIO;
 161                 ide_complete_rq(drive, -EIO, ide_rq_bytes(rq));
 162         }
 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 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
 188 {
 189         special_t *s = &drive->special;
 190         struct ide_cmd cmd;
 191
 192         memset(&cmd, 0, sizeof(cmd));
 193         cmd.protocol = ATA_PROT_NODATA;
 194
 195         if (s->b.set_geometry) {
 196                 s->b.set_geometry = 0;
 197                 ide_tf_set_specify_cmd(drive, &cmd.tf);
 198         } else if (s->b.recalibrate) {
 199                 s->b.recalibrate = 0;
 200                 ide_tf_set_restore_cmd(drive, &cmd.tf);
 201         } else if (s->b.set_multmode) {
 202                 s->b.set_multmode = 0;
 203                 ide_tf_set_setmult_cmd(drive, &cmd.tf);
 204         } else if (s->all) {
 205                 int special = s->all;
 206                 s->all = 0;
 207                 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
 208                 return ide_stopped;
 209         }
 210
 211         cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
 212         cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
 213         cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER;
 214
 215         do_rw_taskfile(drive, &cmd);
 216
 217         return ide_started;
 218 }
 219
 220 /**
 221  *      do_special              -       issue some special commands
 222  *      @drive: drive the command is for
 223  *
 224  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
 225  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
 226  *
 227  *      It used to do much more, but has been scaled back.
 228  */
 229
 230 static ide_startstop_t do_special (ide_drive_t *drive)
 231 {
 232         special_t *s = &drive->special;
 233
 234 #ifdef DEBUG
 235         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
 236 #endif
 237         if (drive->media == ide_disk)
 238                 return ide_disk_special(drive);
 239
 240         s->all = 0;
 241         drive->mult_req = 0;
 242         return ide_stopped;
 243 }
 244
 245 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
 246 {
 247         ide_hwif_t *hwif = drive->hwif;
 248         struct scatterlist *sg = hwif->sg_table;
 249         struct request *rq = cmd->rq;
 250
 251         if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
 252                 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
 253                 cmd->sg_nents = 1;
 254         } else if (!rq->bio) {
 255                 sg_init_one(sg, rq->data, rq->data_len);
 256                 cmd->sg_nents = 1;
 257         } else
 258                 cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
 259 }
 260 EXPORT_SYMBOL_GPL(ide_map_sg);
 261
 262 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
 263 {
 264         cmd->nbytes = cmd->nleft = nr_bytes;
 265         cmd->cursg_ofs = 0;
 266         cmd->cursg = NULL;
 267 }
 268 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 269
 270 /**
 271  *      execute_drive_command   -       issue special drive command
 272  *      @drive: the drive to issue the command on
 273  *      @rq: the request structure holding the command
 274  *
 275  *      execute_drive_cmd() issues a special drive command,  usually
 276  *      initiated by ioctl() from the external hdparm program. The
 277  *      command can be a drive command, drive task or taskfile
 278  *      operation. Weirdly you can call it with NULL to wait for
 279  *      all commands to finish. Don't do this as that is due to change
 280  */
 281
 282 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
 283                 struct request *rq)
 284 {
 285         struct ide_cmd *cmd = rq->special;
 286
 287         if (cmd) {
 288                 if (cmd->protocol == ATA_PROT_PIO) {
 289                         ide_init_sg_cmd(cmd, rq->nr_sectors << 9);
 290                         ide_map_sg(drive, cmd);
 291                 }
 292
 293                 return do_rw_taskfile(drive, cmd);
 294         }
 295
 296         /*
 297          * NULL is actually a valid way of waiting for
 298          * all current requests to be flushed from the queue.
 299          */
 300 #ifdef DEBUG
 301         printk("%s: DRIVE_CMD (null)\n", drive->name);
 302 #endif
 303         rq->errors = 0;
 304         ide_complete_rq(drive, 0, blk_rq_bytes(rq));
 305
 306         return ide_stopped;
 307 }
 308
 309 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 310 {
 311         u8 cmd = rq->cmd[0];
 312
 313         switch (cmd) {
 314         case REQ_PARK_HEADS:
 315         case REQ_UNPARK_HEADS:
 316                 return ide_do_park_unpark(drive, rq);
 317         case REQ_DEVSET_EXEC:
 318                 return ide_do_devset(drive, rq);
 319         case REQ_DRIVE_RESET:
 320                 return ide_do_reset(drive);
 321         default:
 322                 BUG();
 323         }
 324 }
 325
 326 /**
 327  *      start_request   -       start of I/O and command issuing for IDE
 328  *
 329  *      start_request() initiates handling of a new I/O request. It
 330  *      accepts commands and I/O (read/write) requests.
 331  *
 332  *      FIXME: this function needs a rename
 333  */
 334
 335 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 336 {
 337         ide_startstop_t startstop;
 338
 339         BUG_ON(!blk_rq_started(rq));
 340
 341 #ifdef DEBUG
 342         printk("%s: start_request: current=0x%08lx\n",
 343                 drive->hwif->name, (unsigned long) rq);
 344 #endif
 345
 346         /* bail early if we've exceeded max_failures */
 347         if (drive->max_failures && (drive->failures > drive->max_failures)) {
 348                 rq->cmd_flags |= REQ_FAILED;
 349                 goto kill_rq;
 350         }
 351
 352         if (blk_pm_request(rq))
 353                 ide_check_pm_state(drive, rq);
 354
 355         drive->hwif->tp_ops->dev_select(drive);
 356         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
 357                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
 358                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 359                 return startstop;
 360         }
 361         if (!drive->special.all) {
 362                 struct ide_driver *drv;
 363
 364                 /*
 365                  * We reset the drive so we need to issue a SETFEATURES.
 366                  * Do it _after_ do_special() restored device parameters.
 367                  */
 368                 if (drive->current_speed == 0xff)
 369                         ide_config_drive_speed(drive, drive->desired_speed);
 370
 371                 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
 372                         return execute_drive_cmd(drive, rq);
 373                 else if (blk_pm_request(rq)) {
 374                         struct request_pm_state *pm = rq->data;
 375 #ifdef DEBUG_PM
 376                         printk("%s: start_power_step(step: %d)\n",
 377                                 drive->name, pm->pm_step);
 378 #endif
 379                         startstop = ide_start_power_step(drive, rq);
 380                         if (startstop == ide_stopped &&
 381                             pm->pm_step == IDE_PM_COMPLETED)
 382                                 ide_complete_pm_rq(drive, rq);
 383                         return startstop;
 384                 } else if (!rq->rq_disk && blk_special_request(rq))
 385                         /*
 386                          * TODO: Once all ULDs have been modified to
 387                          * check for specific op codes rather than
 388                          * blindly accepting any special request, the
 389                          * check for ->rq_disk above may be replaced
 390                          * by a more suitable mechanism or even
 391                          * dropped entirely.
 392                          */
 393                         return ide_special_rq(drive, rq);
 394
 395                 drv = *(struct ide_driver **)rq->rq_disk->private_data;
 396
 397                 return drv->do_request(drive, rq, rq->sector);
 398         }
 399         return do_special(drive);
 400 kill_rq:
 401         ide_kill_rq(drive, rq);
 402         return ide_stopped;
 403 }
 404
 405 /**
 406  *      ide_stall_queue         -       pause an IDE device
 407  *      @drive: drive to stall
 408  *      @timeout: time to stall for (jiffies)
 409  *
 410  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 411  *      to the port by sleeping for timeout jiffies.
 412  */
 413
 414 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 415 {
 416         if (timeout > WAIT_WORSTCASE)
 417                 timeout = WAIT_WORSTCASE;
 418         drive->sleep = timeout + jiffies;
 419         drive->dev_flags |= IDE_DFLAG_SLEEPING;
 420 }
 421 EXPORT_SYMBOL(ide_stall_queue);
 422
 423 static inline int ide_lock_port(ide_hwif_t *hwif)
 424 {
 425         if (hwif->busy)
 426                 return 1;
 427
 428         hwif->busy = 1;
 429
 430         return 0;
 431 }
 432
 433 static inline void ide_unlock_port(ide_hwif_t *hwif)
 434 {
 435         hwif->busy = 0;
 436 }
 437
 438 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
 439 {
 440         int rc = 0;
 441
 442         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 443                 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
 444                 if (rc == 0) {
 445                         if (host->get_lock)
 446                                 host->get_lock(ide_intr, hwif);
 447                 }
 448         }
 449         return rc;
 450 }
 451
 452 static inline void ide_unlock_host(struct ide_host *host)
 453 {
 454         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 455                 if (host->release_lock)
 456                         host->release_lock();
 457                 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
 458         }
 459 }
 460
 461 /*
 462  * Issue a new request to a device.
 463  */
 464 void do_ide_request(struct request_queue *q)
 465 {
 466         ide_drive_t     *drive = q->queuedata;
 467         ide_hwif_t      *hwif = drive->hwif;
 468         struct ide_host *host = hwif->host;
 469         struct request  *rq = NULL;
 470         ide_startstop_t startstop;
 471
 472         /*
 473          * drive is doing pre-flush, ordered write, post-flush sequence. even
 474          * though that is 3 requests, it must be seen as a single transaction.
 475          * we must not preempt this drive until that is complete
 476          */
 477         if (blk_queue_flushing(q))
 478                 /*
 479                  * small race where queue could get replugged during
 480                  * the 3-request flush cycle, just yank the plug since
 481                  * we want it to finish asap
 482                  */
 483                 blk_remove_plug(q);
 484
 485         spin_unlock_irq(q->queue_lock);
 486
 487         if (ide_lock_host(host, hwif))
 488                 goto plug_device_2;
 489
 490         spin_lock_irq(&hwif->lock);
 491
 492         if (!ide_lock_port(hwif)) {
 493                 ide_hwif_t *prev_port;
 494 repeat:
 495                 prev_port = hwif->host->cur_port;
 496                 hwif->rq = NULL;
 497
 498                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
 499                     time_after(drive->sleep, jiffies)) {
 500                         ide_unlock_port(hwif);
 501                         goto plug_device;
 502                 }
 503
 504                 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
 505                     hwif != prev_port) {
 506                         /*
 507                          * set nIEN for previous port, drives in the
 508                          * quirk_list may not like intr setups/cleanups
 509                          */
 510                         if (prev_port && prev_port->cur_dev->quirk_list == 0)
 511                                 prev_port->tp_ops->write_devctl(prev_port,
 512                                                                 ATA_NIEN |
 513                                                                 ATA_DEVCTL_OBS);
 514
 515                         hwif->host->cur_port = hwif;
 516                 }
 517                 hwif->cur_dev = drive;
 518                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
 519
 520                 spin_unlock_irq(&hwif->lock);
 521                 spin_lock_irq(q->queue_lock);
 522                 /*
 523                  * we know that the queue isn't empty, but this can happen
 524                  * if the q->prep_rq_fn() decides to kill a request
 525                  */
 526                 rq = elv_next_request(drive->queue);
 527                 spin_unlock_irq(q->queue_lock);
 528                 spin_lock_irq(&hwif->lock);
 529
 530                 if (!rq) {
 531                         ide_unlock_port(hwif);
 532                         goto out;
 533                 }
 534
 535                 /*
 536                  * Sanity: don't accept a request that isn't a PM request
 537                  * if we are currently power managed. This is very important as
 538                  * blk_stop_queue() doesn't prevent the elv_next_request()
 539                  * above to return us whatever is in the queue. Since we call
 540                  * ide_do_request() ourselves, we end up taking requests while
 541                  * the queue is blocked...
 542                  *
 543                  * We let requests forced at head of queue with ide-preempt
 544                  * though. I hope that doesn't happen too much, hopefully not
 545                  * unless the subdriver triggers such a thing in its own PM
 546                  * state machine.
 547                  */
 548                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
 549                     blk_pm_request(rq) == 0 &&
 550                     (rq->cmd_flags & REQ_PREEMPT) == 0) {
 551                         /* there should be no pending command at this point */
 552                         ide_unlock_port(hwif);
 553                         goto plug_device;
 554                 }
 555
 556                 hwif->rq = rq;
 557
 558                 spin_unlock_irq(&hwif->lock);
 559                 startstop = start_request(drive, rq);
 560                 spin_lock_irq(&hwif->lock);
 561
 562                 if (startstop == ide_stopped)
 563                         goto repeat;
 564         } else
 565                 goto plug_device;
 566 out:
 567         spin_unlock_irq(&hwif->lock);
 568         if (rq == NULL)
 569                 ide_unlock_host(host);
 570         spin_lock_irq(q->queue_lock);
 571         return;
 572
 573 plug_device:
 574         spin_unlock_irq(&hwif->lock);
 575         ide_unlock_host(host);
 576 plug_device_2:
 577         spin_lock_irq(q->queue_lock);
 578
 579         if (!elv_queue_empty(q))
 580                 blk_plug_device(q);
 581 }
 582
 583 static void ide_plug_device(ide_drive_t *drive)
 584 {
 585         struct request_queue *q = drive->queue;
 586         unsigned long flags;
 587
 588         spin_lock_irqsave(q->queue_lock, flags);
 589         if (!elv_queue_empty(q))
 590                 blk_plug_device(q);
 591         spin_unlock_irqrestore(q->queue_lock, flags);
 592 }
 593
 594 static int drive_is_ready(ide_drive_t *drive)
 595 {
 596         ide_hwif_t *hwif = drive->hwif;
 597         u8 stat = 0;
 598
 599         if (drive->waiting_for_dma)
 600                 return hwif->dma_ops->dma_test_irq(drive);
 601
 602         if (hwif->io_ports.ctl_addr &&
 603             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
 604                 stat = hwif->tp_ops->read_altstatus(hwif);
 605         else
 606                 /* Note: this may clear a pending IRQ!! */
 607                 stat = hwif->tp_ops->read_status(hwif);
 608
 609         if (stat & ATA_BUSY)
 610                 /* drive busy: definitely not interrupting */
 611                 return 0;
 612
 613         /* drive ready: *might* be interrupting */
 614         return 1;
 615 }
 616
 617 /**
 618  *      ide_timer_expiry        -       handle lack of an IDE interrupt
 619  *      @data: timer callback magic (hwif)
 620  *
 621  *      An IDE command has timed out before the expected drive return
 622  *      occurred. At this point we attempt to clean up the current
 623  *      mess. If the current handler includes an expiry handler then
 624  *      we invoke the expiry handler, and providing it is happy the
 625  *      work is done. If that fails we apply generic recovery rules
 626  *      invoking the handler and checking the drive DMA status. We
 627  *      have an excessively incestuous relationship with the DMA
 628  *      logic that wants cleaning up.
 629  */
 630
 631 void ide_timer_expiry (unsigned long data)
 632 {
 633         ide_hwif_t      *hwif = (ide_hwif_t *)data;
 634         ide_drive_t     *uninitialized_var(drive);
 635         ide_handler_t   *handler;
 636         unsigned long   flags;
 637         int             wait = -1;
 638         int             plug_device = 0;
 639
 640         spin_lock_irqsave(&hwif->lock, flags);
 641
 642         handler = hwif->handler;
 643
 644         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
 645                 /*
 646                  * Either a marginal timeout occurred
 647                  * (got the interrupt just as timer expired),
 648                  * or we were "sleeping" to give other devices a chance.
 649                  * Either way, we don't really want to complain about anything.
 650                  */
 651         } else {
 652                 ide_expiry_t *expiry = hwif->expiry;
 653                 ide_startstop_t startstop = ide_stopped;
 654
 655                 drive = hwif->cur_dev;
 656
 657                 if (expiry) {
 658                         wait = expiry(drive);
 659                         if (wait > 0) { /* continue */
 660                                 /* reset timer */
 661                                 hwif->timer.expires = jiffies + wait;
 662                                 hwif->req_gen_timer = hwif->req_gen;
 663                                 add_timer(&hwif->timer);
 664                                 spin_unlock_irqrestore(&hwif->lock, flags);
 665                                 return;
 666                         }
 667                 }
 668                 hwif->handler = NULL;
 669                 hwif->expiry = NULL;
 670                 /*
 671                  * We need to simulate a real interrupt when invoking
 672                  * the handler() function, which means we need to
 673                  * globally mask the specific IRQ:
 674                  */
 675                 spin_unlock(&hwif->lock);
 676                 /* disable_irq_nosync ?? */
 677                 disable_irq(hwif->irq);
 678                 /* local CPU only, as if we were handling an interrupt */
 679                 local_irq_disable();
 680                 if (hwif->polling) {
 681                         startstop = handler(drive);
 682                 } else if (drive_is_ready(drive)) {
 683                         if (drive->waiting_for_dma)
 684                                 hwif->dma_ops->dma_lost_irq(drive);
 685                         if (hwif->ack_intr)
 686                                 hwif->ack_intr(hwif);
 687                         printk(KERN_WARNING "%s: lost interrupt\n",
 688                                 drive->name);
 689                         startstop = handler(drive);
 690                 } else {
 691                         if (drive->waiting_for_dma)
 692                                 startstop = ide_dma_timeout_retry(drive, wait);
 693                         else
 694                                 startstop = ide_error(drive, "irq timeout",
 695                                         hwif->tp_ops->read_status(hwif));
 696                 }
 697                 spin_lock_irq(&hwif->lock);
 698                 enable_irq(hwif->irq);
 699                 if (startstop == ide_stopped && hwif->polling == 0) {
 700                         ide_unlock_port(hwif);
 701                         plug_device = 1;
 702                 }
 703         }
 704         spin_unlock_irqrestore(&hwif->lock, flags);
 705
 706         if (plug_device) {
 707                 ide_unlock_host(hwif->host);
 708                 ide_plug_device(drive);
 709         }
 710 }
 711
 712 /**
 713  *      unexpected_intr         -       handle an unexpected IDE interrupt
 714  *      @irq: interrupt line
 715  *      @hwif: port being processed
 716  *
 717  *      There's nothing really useful we can do with an unexpected interrupt,
 718  *      other than reading the status register (to clear it), and logging it.
 719  *      There should be no way that an irq can happen before we're ready for it,
 720  *      so we needn't worry much about losing an "important" interrupt here.
 721  *
 722  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 723  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
 724  *      looks "good", we just ignore the interrupt completely.
 725  *
 726  *      This routine assumes __cli() is in effect when called.
 727  *
 728  *      If an unexpected interrupt happens on irq15 while we are handling irq14
 729  *      and if the two interfaces are "serialized" (CMD640), then it looks like
 730  *      we could screw up by interfering with a new request being set up for
 731  *      irq15.
 732  *
 733  *      In reality, this is a non-issue.  The new command is not sent unless
 734  *      the drive is ready to accept one, in which case we know the drive is
 735  *      not trying to interrupt us.  And ide_set_handler() is always invoked
 736  *      before completing the issuance of any new drive command, so we will not
 737  *      be accidentally invoked as a result of any valid command completion
 738  *      interrupt.
 739  */
 740
 741 static void unexpected_intr(int irq, ide_hwif_t *hwif)
 742 {
 743         u8 stat = hwif->tp_ops->read_status(hwif);
 744
 745         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
 746                 /* Try to not flood the console with msgs */
 747                 static unsigned long last_msgtime, count;
 748                 ++count;
 749
 750                 if (time_after(jiffies, last_msgtime + HZ)) {
 751                         last_msgtime = jiffies;
 752                         printk(KERN_ERR "%s: unexpected interrupt, "
 753                                 "status=0x%02x, count=%ld\n",
 754                                 hwif->name, stat, count);
 755                 }
 756         }
 757 }
 758
 759 /**
 760  *      ide_intr        -       default IDE interrupt handler
 761  *      @irq: interrupt number
 762  *      @dev_id: hwif
 763  *      @regs: unused weirdness from the kernel irq layer
 764  *
 765  *      This is the default IRQ handler for the IDE layer. You should
 766  *      not need to override it. If you do be aware it is subtle in
 767  *      places
 768  *
 769  *      hwif is the interface in the group currently performing
 770  *      a command. hwif->cur_dev is the drive and hwif->handler is
 771  *      the IRQ handler to call. As we issue a command the handlers
 772  *      step through multiple states, reassigning the handler to the
 773  *      next step in the process. Unlike a smart SCSI controller IDE
 774  *      expects the main processor to sequence the various transfer
 775  *      stages. We also manage a poll timer to catch up with most
 776  *      timeout situations. There are still a few where the handlers
 777  *      don't ever decide to give up.
 778  *
 779  *      The handler eventually returns ide_stopped to indicate the
 780  *      request completed. At this point we issue the next request
 781  *      on the port and the process begins again.
 782  */
 783
 784 irqreturn_t ide_intr (int irq, void *dev_id)
 785 {
 786         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
 787         struct ide_host *host = hwif->host;
 788         ide_drive_t *uninitialized_var(drive);
 789         ide_handler_t *handler;
 790         unsigned long flags;
 791         ide_startstop_t startstop;
 792         irqreturn_t irq_ret = IRQ_NONE;
 793         int plug_device = 0;
 794
 795         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 796                 if (hwif != host->cur_port)
 797                         goto out_early;
 798         }
 799
 800         spin_lock_irqsave(&hwif->lock, flags);
 801
 802         if (hwif->ack_intr && hwif->ack_intr(hwif) == 0)
 803                 goto out;
 804
 805         handler = hwif->handler;
 806
 807         if (handler == NULL || hwif->polling) {
 808                 /*
 809                  * Not expecting an interrupt from this drive.
 810                  * That means this could be:
 811                  *      (1) an interrupt from another PCI device
 812                  *      sharing the same PCI INT# as us.
 813                  * or   (2) a drive just entered sleep or standby mode,
 814                  *      and is interrupting to let us know.
 815                  * or   (3) a spurious interrupt of unknown origin.
 816                  *
 817                  * For PCI, we cannot tell the difference,
 818                  * so in that case we just ignore it and hope it goes away.
 819                  */
 820                 if ((host->irq_flags & IRQF_SHARED) == 0) {
 821                         /*
 822                          * Probably not a shared PCI interrupt,
 823                          * so we can safely try to do something about it:
 824                          */
 825                         unexpected_intr(irq, hwif);
 826                 } else {
 827                         /*
 828                          * Whack the status register, just in case
 829                          * we have a leftover pending IRQ.
 830                          */
 831                         (void)hwif->tp_ops->read_status(hwif);
 832                 }
 833                 goto out;
 834         }
 835
 836         drive = hwif->cur_dev;
 837
 838         if (!drive_is_ready(drive))
 839                 /*
 840                  * This happens regularly when we share a PCI IRQ with
 841                  * another device.  Unfortunately, it can also happen
 842                  * with some buggy drives that trigger the IRQ before
 843                  * their status register is up to date.  Hopefully we have
 844                  * enough advance overhead that the latter isn't a problem.
 845                  */
 846                 goto out;
 847
 848         hwif->handler = NULL;
 849         hwif->expiry = NULL;
 850         hwif->req_gen++;
 851         del_timer(&hwif->timer);
 852         spin_unlock(&hwif->lock);
 853
 854         if (hwif->port_ops && hwif->port_ops->clear_irq)
 855                 hwif->port_ops->clear_irq(drive);
 856
 857         if (drive->dev_flags & IDE_DFLAG_UNMASK)
 858                 local_irq_enable_in_hardirq();
 859
 860         /* service this interrupt, may set handler for next interrupt */
 861         startstop = handler(drive);
 862
 863         spin_lock_irq(&hwif->lock);
 864         /*
 865          * Note that handler() may have set things up for another
 866          * interrupt to occur soon, but it cannot happen until
 867          * we exit from this routine, because it will be the
 868          * same irq as is currently being serviced here, and Linux
 869          * won't allow another of the same (on any CPU) until we return.
 870          */
 871         if (startstop == ide_stopped && hwif->polling == 0) {
 872                 BUG_ON(hwif->handler);
 873                 ide_unlock_port(hwif);
 874                 plug_device = 1;
 875         }
 876         irq_ret = IRQ_HANDLED;
 877 out:
 878         spin_unlock_irqrestore(&hwif->lock, flags);
 879 out_early:
 880         if (plug_device) {
 881                 ide_unlock_host(hwif->host);
 882                 ide_plug_device(drive);
 883         }
 884
 885         return irq_ret;
 886 }
 887 EXPORT_SYMBOL_GPL(ide_intr);
 888
 889 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
 890 {
 891         ide_hwif_t *hwif = drive->hwif;
 892         u8 buf[4] = { 0 };
 893
 894         while (len > 0) {
 895                 if (write)
 896                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
 897                 else
 898                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
 899                 len -= 4;
 900         }
 901 }
 902 EXPORT_SYMBOL_GPL(ide_pad_transfer);