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                 tf->data = data[0];
  90                 tf->hob_data = data[1];
  91         }
  92
  93         tp_ops->tf_read(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, tf);
 101                 } else
 102                         drive->dev_flags |= IDE_DFLAG_PARKED;
 103         }
 104
 105         if (rq && rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
 106                 memcpy(rq->special, cmd, sizeof(*cmd));
 107
 108         if (cmd->tf_flags & IDE_TFLAG_DYN)
 109                 kfree(cmd);
 110 }
 111
 112 /* obsolete, blk_rq_bytes() should be used instead */
 113 unsigned int ide_rq_bytes(struct request *rq)
 114 {
 115         if (blk_pc_request(rq))
 116                 return rq->data_len;
 117         else
 118                 return rq->hard_cur_sectors << 9;
 119 }
 120 EXPORT_SYMBOL_GPL(ide_rq_bytes);
 121
 122 int ide_complete_rq(ide_drive_t *drive, int error, unsigned int nr_bytes)
 123 {
 124         ide_hwif_t *hwif = drive->hwif;
 125         struct request *rq = hwif->rq;
 126         int rc;
 127
 128         /*
 129          * if failfast is set on a request, override number of sectors
 130          * and complete the whole request right now
 131          */
 132         if (blk_noretry_request(rq) && error <= 0)
 133                 nr_bytes = rq->hard_nr_sectors << 9;
 134
 135         rc = ide_end_rq(drive, rq, error, nr_bytes);
 136         if (rc == 0)
 137                 hwif->rq = NULL;
 138
 139         return rc;
 140 }
 141 EXPORT_SYMBOL(ide_complete_rq);
 142
 143 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
 144 {
 145         u8 drv_req = blk_special_request(rq) && rq->rq_disk;
 146         u8 media = drive->media;
 147
 148         drive->failed_pc = NULL;
 149
 150         if ((media == ide_floppy || media == ide_tape) && drv_req) {
 151                 rq->errors = 0;
 152                 ide_complete_rq(drive, 0, blk_rq_bytes(rq));
 153         } else {
 154                 if (media == ide_tape)
 155                         rq->errors = IDE_DRV_ERROR_GENERAL;
 156                 else if (blk_fs_request(rq) == 0 && rq->errors == 0)
 157                         rq->errors = -EIO;
 158                 ide_complete_rq(drive, -EIO, ide_rq_bytes(rq));
 159         }
 160 }
 161
 162 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 163 {
 164         tf->nsect   = drive->sect;
 165         tf->lbal    = drive->sect;
 166         tf->lbam    = drive->cyl;
 167         tf->lbah    = drive->cyl >> 8;
 168         tf->device  = (drive->head - 1) | drive->select;
 169         tf->command = ATA_CMD_INIT_DEV_PARAMS;
 170 }
 171
 172 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 173 {
 174         tf->nsect   = drive->sect;
 175         tf->command = ATA_CMD_RESTORE;
 176 }
 177
 178 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 179 {
 180         tf->nsect   = drive->mult_req;
 181         tf->command = ATA_CMD_SET_MULTI;
 182 }
 183
 184 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
 185 {
 186         special_t *s = &drive->special;
 187         struct ide_cmd cmd;
 188
 189         memset(&cmd, 0, sizeof(cmd));
 190         cmd.protocol = ATA_PROT_NODATA;
 191
 192         if (s->b.set_geometry) {
 193                 s->b.set_geometry = 0;
 194                 ide_tf_set_specify_cmd(drive, &cmd.tf);
 195         } else if (s->b.recalibrate) {
 196                 s->b.recalibrate = 0;
 197                 ide_tf_set_restore_cmd(drive, &cmd.tf);
 198         } else if (s->b.set_multmode) {
 199                 s->b.set_multmode = 0;
 200                 ide_tf_set_setmult_cmd(drive, &cmd.tf);
 201         } else if (s->all) {
 202                 int special = s->all;
 203                 s->all = 0;
 204                 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
 205                 return ide_stopped;
 206         }
 207
 208         cmd.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE |
 209                        IDE_TFLAG_CUSTOM_HANDLER;
 210
 211         do_rw_taskfile(drive, &cmd);
 212
 213         return ide_started;
 214 }
 215
 216 /**
 217  *      do_special              -       issue some special commands
 218  *      @drive: drive the command is for
 219  *
 220  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
 221  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
 222  *
 223  *      It used to do much more, but has been scaled back.
 224  */
 225
 226 static ide_startstop_t do_special (ide_drive_t *drive)
 227 {
 228         special_t *s = &drive->special;
 229
 230 #ifdef DEBUG
 231         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
 232 #endif
 233         if (drive->media == ide_disk)
 234                 return ide_disk_special(drive);
 235
 236         s->all = 0;
 237         drive->mult_req = 0;
 238         return ide_stopped;
 239 }
 240
 241 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
 242 {
 243         ide_hwif_t *hwif = drive->hwif;
 244         struct scatterlist *sg = hwif->sg_table;
 245         struct request *rq = cmd->rq;
 246
 247         if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
 248                 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
 249                 cmd->sg_nents = 1;
 250         } else if (!rq->bio) {
 251                 sg_init_one(sg, rq->data, rq->data_len);
 252                 cmd->sg_nents = 1;
 253         } else
 254                 cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
 255 }
 256 EXPORT_SYMBOL_GPL(ide_map_sg);
 257
 258 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
 259 {
 260         cmd->nbytes = cmd->nleft = nr_bytes;
 261         cmd->cursg_ofs = 0;
 262         cmd->cursg = NULL;
 263 }
 264 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 265
 266 /**
 267  *      execute_drive_command   -       issue special drive command
 268  *      @drive: the drive to issue the command on
 269  *      @rq: the request structure holding the command
 270  *
 271  *      execute_drive_cmd() issues a special drive command,  usually
 272  *      initiated by ioctl() from the external hdparm program. The
 273  *      command can be a drive command, drive task or taskfile
 274  *      operation. Weirdly you can call it with NULL to wait for
 275  *      all commands to finish. Don't do this as that is due to change
 276  */
 277
 278 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
 279                 struct request *rq)
 280 {
 281         struct ide_cmd *cmd = rq->special;
 282
 283         if (cmd) {
 284                 if (cmd->protocol == ATA_PROT_PIO) {
 285                         ide_init_sg_cmd(cmd, rq->nr_sectors << 9);
 286                         ide_map_sg(drive, cmd);
 287                 }
 288
 289                 return do_rw_taskfile(drive, cmd);
 290         }
 291
 292         /*
 293          * NULL is actually a valid way of waiting for
 294          * all current requests to be flushed from the queue.
 295          */
 296 #ifdef DEBUG
 297         printk("%s: DRIVE_CMD (null)\n", drive->name);
 298 #endif
 299         rq->errors = 0;
 300         ide_complete_rq(drive, 0, blk_rq_bytes(rq));
 301
 302         return ide_stopped;
 303 }
 304
 305 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 306 {
 307         u8 cmd = rq->cmd[0];
 308
 309         switch (cmd) {
 310         case REQ_PARK_HEADS:
 311         case REQ_UNPARK_HEADS:
 312                 return ide_do_park_unpark(drive, rq);
 313         case REQ_DEVSET_EXEC:
 314                 return ide_do_devset(drive, rq);
 315         case REQ_DRIVE_RESET:
 316                 return ide_do_reset(drive);
 317         default:
 318                 BUG();
 319         }
 320 }
 321
 322 /**
 323  *      start_request   -       start of I/O and command issuing for IDE
 324  *
 325  *      start_request() initiates handling of a new I/O request. It
 326  *      accepts commands and I/O (read/write) requests.
 327  *
 328  *      FIXME: this function needs a rename
 329  */
 330
 331 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 332 {
 333         ide_startstop_t startstop;
 334
 335         BUG_ON(!blk_rq_started(rq));
 336
 337 #ifdef DEBUG
 338         printk("%s: start_request: current=0x%08lx\n",
 339                 drive->hwif->name, (unsigned long) rq);
 340 #endif
 341
 342         /* bail early if we've exceeded max_failures */
 343         if (drive->max_failures && (drive->failures > drive->max_failures)) {
 344                 rq->cmd_flags |= REQ_FAILED;
 345                 goto kill_rq;
 346         }
 347
 348         if (blk_pm_request(rq))
 349                 ide_check_pm_state(drive, rq);
 350
 351         drive->hwif->tp_ops->dev_select(drive);
 352         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
 353                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
 354                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 355                 return startstop;
 356         }
 357         if (!drive->special.all) {
 358                 struct ide_driver *drv;
 359
 360                 /*
 361                  * We reset the drive so we need to issue a SETFEATURES.
 362                  * Do it _after_ do_special() restored device parameters.
 363                  */
 364                 if (drive->current_speed == 0xff)
 365                         ide_config_drive_speed(drive, drive->desired_speed);
 366
 367                 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
 368                         return execute_drive_cmd(drive, rq);
 369                 else if (blk_pm_request(rq)) {
 370                         struct request_pm_state *pm = rq->data;
 371 #ifdef DEBUG_PM
 372                         printk("%s: start_power_step(step: %d)\n",
 373                                 drive->name, pm->pm_step);
 374 #endif
 375                         startstop = ide_start_power_step(drive, rq);
 376                         if (startstop == ide_stopped &&
 377                             pm->pm_step == IDE_PM_COMPLETED)
 378                                 ide_complete_pm_rq(drive, rq);
 379                         return startstop;
 380                 } else if (!rq->rq_disk && blk_special_request(rq))
 381                         /*
 382                          * TODO: Once all ULDs have been modified to
 383                          * check for specific op codes rather than
 384                          * blindly accepting any special request, the
 385                          * check for ->rq_disk above may be replaced
 386                          * by a more suitable mechanism or even
 387                          * dropped entirely.
 388                          */
 389                         return ide_special_rq(drive, rq);
 390
 391                 drv = *(struct ide_driver **)rq->rq_disk->private_data;
 392
 393                 return drv->do_request(drive, rq, rq->sector);
 394         }
 395         return do_special(drive);
 396 kill_rq:
 397         ide_kill_rq(drive, rq);
 398         return ide_stopped;
 399 }
 400
 401 /**
 402  *      ide_stall_queue         -       pause an IDE device
 403  *      @drive: drive to stall
 404  *      @timeout: time to stall for (jiffies)
 405  *
 406  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 407  *      to the port by sleeping for timeout jiffies.
 408  */
 409
 410 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 411 {
 412         if (timeout > WAIT_WORSTCASE)
 413                 timeout = WAIT_WORSTCASE;
 414         drive->sleep = timeout + jiffies;
 415         drive->dev_flags |= IDE_DFLAG_SLEEPING;
 416 }
 417 EXPORT_SYMBOL(ide_stall_queue);
 418
 419 static inline int ide_lock_port(ide_hwif_t *hwif)
 420 {
 421         if (hwif->busy)
 422                 return 1;
 423
 424         hwif->busy = 1;
 425
 426         return 0;
 427 }
 428
 429 static inline void ide_unlock_port(ide_hwif_t *hwif)
 430 {
 431         hwif->busy = 0;
 432 }
 433
 434 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
 435 {
 436         int rc = 0;
 437
 438         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 439                 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
 440                 if (rc == 0) {
 441                         if (host->get_lock)
 442                                 host->get_lock(ide_intr, hwif);
 443                 }
 444         }
 445         return rc;
 446 }
 447
 448 static inline void ide_unlock_host(struct ide_host *host)
 449 {
 450         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 451                 if (host->release_lock)
 452                         host->release_lock();
 453                 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
 454         }
 455 }
 456
 457 /*
 458  * Issue a new request to a device.
 459  */
 460 void do_ide_request(struct request_queue *q)
 461 {
 462         ide_drive_t     *drive = q->queuedata;
 463         ide_hwif_t      *hwif = drive->hwif;
 464         struct ide_host *host = hwif->host;
 465         struct request  *rq = NULL;
 466         ide_startstop_t startstop;
 467
 468         /*
 469          * drive is doing pre-flush, ordered write, post-flush sequence. even
 470          * though that is 3 requests, it must be seen as a single transaction.
 471          * we must not preempt this drive until that is complete
 472          */
 473         if (blk_queue_flushing(q))
 474                 /*
 475                  * small race where queue could get replugged during
 476                  * the 3-request flush cycle, just yank the plug since
 477                  * we want it to finish asap
 478                  */
 479                 blk_remove_plug(q);
 480
 481         spin_unlock_irq(q->queue_lock);
 482
 483         if (ide_lock_host(host, hwif))
 484                 goto plug_device_2;
 485
 486         spin_lock_irq(&hwif->lock);
 487
 488         if (!ide_lock_port(hwif)) {
 489                 ide_hwif_t *prev_port;
 490 repeat:
 491                 prev_port = hwif->host->cur_port;
 492                 hwif->rq = NULL;
 493
 494                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
 495                     time_after(drive->sleep, jiffies)) {
 496                         ide_unlock_port(hwif);
 497                         goto plug_device;
 498                 }
 499
 500                 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
 501                     hwif != prev_port) {
 502                         /*
 503                          * set nIEN for previous port, drives in the
 504                          * quirk_list may not like intr setups/cleanups
 505                          */
 506                         if (prev_port && prev_port->cur_dev->quirk_list == 0)
 507                                 prev_port->tp_ops->write_devctl(prev_port,
 508                                                                 ATA_NIEN |
 509                                                                 ATA_DEVCTL_OBS);
 510
 511                         hwif->host->cur_port = hwif;
 512                 }
 513                 hwif->cur_dev = drive;
 514                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
 515
 516                 spin_unlock_irq(&hwif->lock);
 517                 spin_lock_irq(q->queue_lock);
 518                 /*
 519                  * we know that the queue isn't empty, but this can happen
 520                  * if the q->prep_rq_fn() decides to kill a request
 521                  */
 522                 rq = elv_next_request(drive->queue);
 523                 spin_unlock_irq(q->queue_lock);
 524                 spin_lock_irq(&hwif->lock);
 525
 526                 if (!rq) {
 527                         ide_unlock_port(hwif);
 528                         goto out;
 529                 }
 530
 531                 /*
 532                  * Sanity: don't accept a request that isn't a PM request
 533                  * if we are currently power managed. This is very important as
 534                  * blk_stop_queue() doesn't prevent the elv_next_request()
 535                  * above to return us whatever is in the queue. Since we call
 536                  * ide_do_request() ourselves, we end up taking requests while
 537                  * the queue is blocked...
 538                  *
 539                  * We let requests forced at head of queue with ide-preempt
 540                  * though. I hope that doesn't happen too much, hopefully not
 541                  * unless the subdriver triggers such a thing in its own PM
 542                  * state machine.
 543                  */
 544                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
 545                     blk_pm_request(rq) == 0 &&
 546                     (rq->cmd_flags & REQ_PREEMPT) == 0) {
 547                         /* there should be no pending command at this point */
 548                         ide_unlock_port(hwif);
 549                         goto plug_device;
 550                 }
 551
 552                 hwif->rq = rq;
 553
 554                 spin_unlock_irq(&hwif->lock);
 555                 startstop = start_request(drive, rq);
 556                 spin_lock_irq(&hwif->lock);
 557
 558                 if (startstop == ide_stopped)
 559                         goto repeat;
 560         } else
 561                 goto plug_device;
 562 out:
 563         spin_unlock_irq(&hwif->lock);
 564         if (rq == NULL)
 565                 ide_unlock_host(host);
 566         spin_lock_irq(q->queue_lock);
 567         return;
 568
 569 plug_device:
 570         spin_unlock_irq(&hwif->lock);
 571         ide_unlock_host(host);
 572 plug_device_2:
 573         spin_lock_irq(q->queue_lock);
 574
 575         if (!elv_queue_empty(q))
 576                 blk_plug_device(q);
 577 }
 578
 579 static void ide_plug_device(ide_drive_t *drive)
 580 {
 581         struct request_queue *q = drive->queue;
 582         unsigned long flags;
 583
 584         spin_lock_irqsave(q->queue_lock, flags);
 585         if (!elv_queue_empty(q))
 586                 blk_plug_device(q);
 587         spin_unlock_irqrestore(q->queue_lock, flags);
 588 }
 589
 590 static int drive_is_ready(ide_drive_t *drive)
 591 {
 592         ide_hwif_t *hwif = drive->hwif;
 593         u8 stat = 0;
 594
 595         if (drive->waiting_for_dma)
 596                 return hwif->dma_ops->dma_test_irq(drive);
 597
 598         if (hwif->io_ports.ctl_addr &&
 599             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
 600                 stat = hwif->tp_ops->read_altstatus(hwif);
 601         else
 602                 /* Note: this may clear a pending IRQ!! */
 603                 stat = hwif->tp_ops->read_status(hwif);
 604
 605         if (stat & ATA_BUSY)
 606                 /* drive busy: definitely not interrupting */
 607                 return 0;
 608
 609         /* drive ready: *might* be interrupting */
 610         return 1;
 611 }
 612
 613 /**
 614  *      ide_timer_expiry        -       handle lack of an IDE interrupt
 615  *      @data: timer callback magic (hwif)
 616  *
 617  *      An IDE command has timed out before the expected drive return
 618  *      occurred. At this point we attempt to clean up the current
 619  *      mess. If the current handler includes an expiry handler then
 620  *      we invoke the expiry handler, and providing it is happy the
 621  *      work is done. If that fails we apply generic recovery rules
 622  *      invoking the handler and checking the drive DMA status. We
 623  *      have an excessively incestuous relationship with the DMA
 624  *      logic that wants cleaning up.
 625  */
 626
 627 void ide_timer_expiry (unsigned long data)
 628 {
 629         ide_hwif_t      *hwif = (ide_hwif_t *)data;
 630         ide_drive_t     *uninitialized_var(drive);
 631         ide_handler_t   *handler;
 632         unsigned long   flags;
 633         int             wait = -1;
 634         int             plug_device = 0;
 635
 636         spin_lock_irqsave(&hwif->lock, flags);
 637
 638         handler = hwif->handler;
 639
 640         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
 641                 /*
 642                  * Either a marginal timeout occurred
 643                  * (got the interrupt just as timer expired),
 644                  * or we were "sleeping" to give other devices a chance.
 645                  * Either way, we don't really want to complain about anything.
 646                  */
 647         } else {
 648                 ide_expiry_t *expiry = hwif->expiry;
 649                 ide_startstop_t startstop = ide_stopped;
 650
 651                 drive = hwif->cur_dev;
 652
 653                 if (expiry) {
 654                         wait = expiry(drive);
 655                         if (wait > 0) { /* continue */
 656                                 /* reset timer */
 657                                 hwif->timer.expires = jiffies + wait;
 658                                 hwif->req_gen_timer = hwif->req_gen;
 659                                 add_timer(&hwif->timer);
 660                                 spin_unlock_irqrestore(&hwif->lock, flags);
 661                                 return;
 662                         }
 663                 }
 664                 hwif->handler = NULL;
 665                 hwif->expiry = NULL;
 666                 /*
 667                  * We need to simulate a real interrupt when invoking
 668                  * the handler() function, which means we need to
 669                  * globally mask the specific IRQ:
 670                  */
 671                 spin_unlock(&hwif->lock);
 672                 /* disable_irq_nosync ?? */
 673                 disable_irq(hwif->irq);
 674                 /* local CPU only, as if we were handling an interrupt */
 675                 local_irq_disable();
 676                 if (hwif->polling) {
 677                         startstop = handler(drive);
 678                 } else if (drive_is_ready(drive)) {
 679                         if (drive->waiting_for_dma)
 680                                 hwif->dma_ops->dma_lost_irq(drive);
 681                         if (hwif->ack_intr)
 682                                 hwif->ack_intr(hwif);
 683                         printk(KERN_WARNING "%s: lost interrupt\n",
 684                                 drive->name);
 685                         startstop = handler(drive);
 686                 } else {
 687                         if (drive->waiting_for_dma)
 688                                 startstop = ide_dma_timeout_retry(drive, wait);
 689                         else
 690                                 startstop = ide_error(drive, "irq timeout",
 691                                         hwif->tp_ops->read_status(hwif));
 692                 }
 693                 spin_lock_irq(&hwif->lock);
 694                 enable_irq(hwif->irq);
 695                 if (startstop == ide_stopped) {
 696                         ide_unlock_port(hwif);
 697                         plug_device = 1;
 698                 }
 699         }
 700         spin_unlock_irqrestore(&hwif->lock, flags);
 701
 702         if (plug_device) {
 703                 ide_unlock_host(hwif->host);
 704                 ide_plug_device(drive);
 705         }
 706 }
 707
 708 /**
 709  *      unexpected_intr         -       handle an unexpected IDE interrupt
 710  *      @irq: interrupt line
 711  *      @hwif: port being processed
 712  *
 713  *      There's nothing really useful we can do with an unexpected interrupt,
 714  *      other than reading the status register (to clear it), and logging it.
 715  *      There should be no way that an irq can happen before we're ready for it,
 716  *      so we needn't worry much about losing an "important" interrupt here.
 717  *
 718  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 719  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
 720  *      looks "good", we just ignore the interrupt completely.
 721  *
 722  *      This routine assumes __cli() is in effect when called.
 723  *
 724  *      If an unexpected interrupt happens on irq15 while we are handling irq14
 725  *      and if the two interfaces are "serialized" (CMD640), then it looks like
 726  *      we could screw up by interfering with a new request being set up for
 727  *      irq15.
 728  *
 729  *      In reality, this is a non-issue.  The new command is not sent unless
 730  *      the drive is ready to accept one, in which case we know the drive is
 731  *      not trying to interrupt us.  And ide_set_handler() is always invoked
 732  *      before completing the issuance of any new drive command, so we will not
 733  *      be accidentally invoked as a result of any valid command completion
 734  *      interrupt.
 735  */
 736
 737 static void unexpected_intr(int irq, ide_hwif_t *hwif)
 738 {
 739         u8 stat = hwif->tp_ops->read_status(hwif);
 740
 741         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
 742                 /* Try to not flood the console with msgs */
 743                 static unsigned long last_msgtime, count;
 744                 ++count;
 745
 746                 if (time_after(jiffies, last_msgtime + HZ)) {
 747                         last_msgtime = jiffies;
 748                         printk(KERN_ERR "%s: unexpected interrupt, "
 749                                 "status=0x%02x, count=%ld\n",
 750                                 hwif->name, stat, count);
 751                 }
 752         }
 753 }
 754
 755 /**
 756  *      ide_intr        -       default IDE interrupt handler
 757  *      @irq: interrupt number
 758  *      @dev_id: hwif
 759  *      @regs: unused weirdness from the kernel irq layer
 760  *
 761  *      This is the default IRQ handler for the IDE layer. You should
 762  *      not need to override it. If you do be aware it is subtle in
 763  *      places
 764  *
 765  *      hwif is the interface in the group currently performing
 766  *      a command. hwif->cur_dev is the drive and hwif->handler is
 767  *      the IRQ handler to call. As we issue a command the handlers
 768  *      step through multiple states, reassigning the handler to the
 769  *      next step in the process. Unlike a smart SCSI controller IDE
 770  *      expects the main processor to sequence the various transfer
 771  *      stages. We also manage a poll timer to catch up with most
 772  *      timeout situations. There are still a few where the handlers
 773  *      don't ever decide to give up.
 774  *
 775  *      The handler eventually returns ide_stopped to indicate the
 776  *      request completed. At this point we issue the next request
 777  *      on the port and the process begins again.
 778  */
 779
 780 irqreturn_t ide_intr (int irq, void *dev_id)
 781 {
 782         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
 783         struct ide_host *host = hwif->host;
 784         ide_drive_t *uninitialized_var(drive);
 785         ide_handler_t *handler;
 786         unsigned long flags;
 787         ide_startstop_t startstop;
 788         irqreturn_t irq_ret = IRQ_NONE;
 789         int plug_device = 0;
 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->ack_intr && hwif->ack_intr(hwif) == 0)
 799                 goto out;
 800
 801         handler = hwif->handler;
 802
 803         if (handler == NULL || hwif->polling) {
 804                 /*
 805                  * Not expecting an interrupt from this drive.
 806                  * That means this could be:
 807                  *      (1) an interrupt from another PCI device
 808                  *      sharing the same PCI INT# as us.
 809                  * or   (2) a drive just entered sleep or standby mode,
 810                  *      and is interrupting to let us know.
 811                  * or   (3) a spurious interrupt of unknown origin.
 812                  *
 813                  * For PCI, we cannot tell the difference,
 814                  * so in that case we just ignore it and hope it goes away.
 815                  */
 816                 if ((host->irq_flags & IRQF_SHARED) == 0) {
 817                         /*
 818                          * Probably not a shared PCI interrupt,
 819                          * so we can safely try to do something about it:
 820                          */
 821                         unexpected_intr(irq, hwif);
 822                 } else {
 823                         /*
 824                          * Whack the status register, just in case
 825                          * we have a leftover pending IRQ.
 826                          */
 827                         (void)hwif->tp_ops->read_status(hwif);
 828                 }
 829                 goto out;
 830         }
 831
 832         drive = hwif->cur_dev;
 833
 834         if (!drive_is_ready(drive))
 835                 /*
 836                  * This happens regularly when we share a PCI IRQ with
 837                  * another device.  Unfortunately, it can also happen
 838                  * with some buggy drives that trigger the IRQ before
 839                  * their status register is up to date.  Hopefully we have
 840                  * enough advance overhead that the latter isn't a problem.
 841                  */
 842                 goto out;
 843
 844         hwif->handler = NULL;
 845         hwif->expiry = NULL;
 846         hwif->req_gen++;
 847         del_timer(&hwif->timer);
 848         spin_unlock(&hwif->lock);
 849
 850         if (hwif->port_ops && hwif->port_ops->clear_irq)
 851                 hwif->port_ops->clear_irq(drive);
 852
 853         if (drive->dev_flags & IDE_DFLAG_UNMASK)
 854                 local_irq_enable_in_hardirq();
 855
 856         /* service this interrupt, may set handler for next interrupt */
 857         startstop = handler(drive);
 858
 859         spin_lock_irq(&hwif->lock);
 860         /*
 861          * Note that handler() may have set things up for another
 862          * interrupt to occur soon, but it cannot happen until
 863          * we exit from this routine, because it will be the
 864          * same irq as is currently being serviced here, and Linux
 865          * won't allow another of the same (on any CPU) until we return.
 866          */
 867         if (startstop == ide_stopped) {
 868                 BUG_ON(hwif->handler);
 869                 ide_unlock_port(hwif);
 870                 plug_device = 1;
 871         }
 872         irq_ret = IRQ_HANDLED;
 873 out:
 874         spin_unlock_irqrestore(&hwif->lock, flags);
 875 out_early:
 876         if (plug_device) {
 877                 ide_unlock_host(hwif->host);
 878                 ide_plug_device(drive);
 879         }
 880
 881         return irq_ret;
 882 }
 883 EXPORT_SYMBOL_GPL(ide_intr);
 884
 885 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
 886 {
 887         ide_hwif_t *hwif = drive->hwif;
 888         u8 buf[4] = { 0 };
 889
 890         while (len > 0) {
 891                 if (write)
 892                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
 893                 else
 894                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
 895                 len -= 4;
 896         }
 897 }
 898 EXPORT_SYMBOL_GPL(ide_pad_transfer);