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/config.h>
  28 #include <linux/module.h>
  29 #include <linux/types.h>
  30 #include <linux/string.h>
  31 #include <linux/kernel.h>
  32 #include <linux/timer.h>
  33 #include <linux/mm.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/major.h>
  36 #include <linux/errno.h>
  37 #include <linux/genhd.h>
  38 #include <linux/blkpg.h>
  39 #include <linux/slab.h>
  40 #include <linux/init.h>
  41 #include <linux/pci.h>
  42 #include <linux/delay.h>
  43 #include <linux/ide.h>
  44 #include <linux/completion.h>
  45 #include <linux/reboot.h>
  46 #include <linux/cdrom.h>
  47 #include <linux/seq_file.h>
  48 #include <linux/device.h>
  49 #include <linux/kmod.h>
  50 #include <linux/scatterlist.h>
  51
  52 #include <asm/byteorder.h>
  53 #include <asm/irq.h>
  54 #include <asm/uaccess.h>
  55 #include <asm/io.h>
  56 #include <asm/bitops.h>
  57
  58 static int __ide_end_request(ide_drive_t *drive, struct request *rq,
  59                              int uptodate, int nr_sectors)
  60 {
  61         int ret = 1;
  62
  63         BUG_ON(!(rq->flags & REQ_STARTED));
  64
  65         /*
  66          * if failfast is set on a request, override number of sectors and
  67          * complete the whole request right now
  68          */
  69         if (blk_noretry_request(rq) && end_io_error(uptodate))
  70                 nr_sectors = rq->hard_nr_sectors;
  71
  72         if (!blk_fs_request(rq) && end_io_error(uptodate) && !rq->errors)
  73                 rq->errors = -EIO;
  74
  75         /*
  76          * decide whether to reenable DMA -- 3 is a random magic for now,
  77          * if we DMA timeout more than 3 times, just stay in PIO
  78          */
  79         if (drive->state == DMA_PIO_RETRY && drive->retry_pio <= 3) {
  80                 drive->state = 0;
  81                 HWGROUP(drive)->hwif->ide_dma_on(drive);
  82         }
  83
  84         if (!end_that_request_first(rq, uptodate, nr_sectors)) {
  85                 add_disk_randomness(rq->rq_disk);
  86                 blkdev_dequeue_request(rq);
  87                 HWGROUP(drive)->rq = NULL;
  88                 end_that_request_last(rq, uptodate);
  89                 ret = 0;
  90         }
  91
  92         return ret;
  93 }
  94
  95 /**
  96  *      ide_end_request         -       complete an IDE I/O
  97  *      @drive: IDE device for the I/O
  98  *      @uptodate:
  99  *      @nr_sectors: number of sectors completed
 100  *
 101  *      This is our end_request wrapper function. We complete the I/O
 102  *      update random number input and dequeue the request, which if
 103  *      it was tagged may be out of order.
 104  */
 105
 106 int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
 107 {
 108         struct request *rq;
 109         unsigned long flags;
 110         int ret = 1;
 111
 112         /*
 113          * room for locking improvements here, the calls below don't
 114          * need the queue lock held at all
 115          */
 116         spin_lock_irqsave(&ide_lock, flags);
 117         rq = HWGROUP(drive)->rq;
 118
 119         if (!nr_sectors)
 120                 nr_sectors = rq->hard_cur_sectors;
 121
 122         ret = __ide_end_request(drive, rq, uptodate, nr_sectors);
 123
 124         spin_unlock_irqrestore(&ide_lock, flags);
 125         return ret;
 126 }
 127 EXPORT_SYMBOL(ide_end_request);
 128
 129 /*
 130  * Power Management state machine. This one is rather trivial for now,
 131  * we should probably add more, like switching back to PIO on suspend
 132  * to help some BIOSes, re-do the door locking on resume, etc...
 133  */
 134
 135 enum {
 136         ide_pm_flush_cache      = ide_pm_state_start_suspend,
 137         idedisk_pm_standby,
 138
 139         idedisk_pm_idle         = ide_pm_state_start_resume,
 140         ide_pm_restore_dma,
 141 };
 142
 143 static void ide_complete_power_step(ide_drive_t *drive, struct request *rq, u8 stat, u8 error)
 144 {
 145         if (drive->media != ide_disk)
 146                 return;
 147
 148         switch (rq->pm->pm_step) {
 149         case ide_pm_flush_cache:        /* Suspend step 1 (flush cache) complete */
 150                 if (rq->pm->pm_state == PM_EVENT_FREEZE)
 151                         rq->pm->pm_step = ide_pm_state_completed;
 152                 else
 153                         rq->pm->pm_step = idedisk_pm_standby;
 154                 break;
 155         case idedisk_pm_standby:        /* Suspend step 2 (standby) complete */
 156                 rq->pm->pm_step = ide_pm_state_completed;
 157                 break;
 158         case idedisk_pm_idle:           /* Resume step 1 (idle) complete */
 159                 rq->pm->pm_step = ide_pm_restore_dma;
 160                 break;
 161         }
 162 }
 163
 164 static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
 165 {
 166         ide_task_t *args = rq->special;
 167
 168         memset(args, 0, sizeof(*args));
 169
 170         if (drive->media != ide_disk) {
 171                 /* skip idedisk_pm_idle for ATAPI devices */
 172                 if (rq->pm->pm_step == idedisk_pm_idle)
 173                         rq->pm->pm_step = ide_pm_restore_dma;
 174         }
 175
 176         switch (rq->pm->pm_step) {
 177         case ide_pm_flush_cache:        /* Suspend step 1 (flush cache) */
 178                 if (drive->media != ide_disk)
 179                         break;
 180                 /* Not supported? Switch to next step now. */
 181                 if (!drive->wcache || !ide_id_has_flush_cache(drive->id)) {
 182                         ide_complete_power_step(drive, rq, 0, 0);
 183                         return ide_stopped;
 184                 }
 185                 if (ide_id_has_flush_cache_ext(drive->id))
 186                         args->tfRegister[IDE_COMMAND_OFFSET] = WIN_FLUSH_CACHE_EXT;
 187                 else
 188                         args->tfRegister[IDE_COMMAND_OFFSET] = WIN_FLUSH_CACHE;
 189                 args->command_type = IDE_DRIVE_TASK_NO_DATA;
 190                 args->handler      = &task_no_data_intr;
 191                 return do_rw_taskfile(drive, args);
 192
 193         case idedisk_pm_standby:        /* Suspend step 2 (standby) */
 194                 args->tfRegister[IDE_COMMAND_OFFSET] = WIN_STANDBYNOW1;
 195                 args->command_type = IDE_DRIVE_TASK_NO_DATA;
 196                 args->handler      = &task_no_data_intr;
 197                 return do_rw_taskfile(drive, args);
 198
 199         case idedisk_pm_idle:           /* Resume step 1 (idle) */
 200                 args->tfRegister[IDE_COMMAND_OFFSET] = WIN_IDLEIMMEDIATE;
 201                 args->command_type = IDE_DRIVE_TASK_NO_DATA;
 202                 args->handler = task_no_data_intr;
 203                 return do_rw_taskfile(drive, args);
 204
 205         case ide_pm_restore_dma:        /* Resume step 2 (restore DMA) */
 206                 /*
 207                  * Right now, all we do is call hwif->ide_dma_check(drive),
 208                  * we could be smarter and check for current xfer_speed
 209                  * in struct drive etc...
 210                  */
 211                 if ((drive->id->capability & 1) == 0)
 212                         break;
 213                 if (drive->hwif->ide_dma_check == NULL)
 214                         break;
 215                 drive->hwif->ide_dma_check(drive);
 216                 break;
 217         }
 218         rq->pm->pm_step = ide_pm_state_completed;
 219         return ide_stopped;
 220 }
 221
 222 /**
 223  *      ide_complete_pm_request - end the current Power Management request
 224  *      @drive: target drive
 225  *      @rq: request
 226  *
 227  *      This function cleans up the current PM request and stops the queue
 228  *      if necessary.
 229  */
 230 static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
 231 {
 232         unsigned long flags;
 233
 234 #ifdef DEBUG_PM
 235         printk("%s: completing PM request, %s\n", drive->name,
 236                blk_pm_suspend_request(rq) ? "suspend" : "resume");
 237 #endif
 238         spin_lock_irqsave(&ide_lock, flags);
 239         if (blk_pm_suspend_request(rq)) {
 240                 blk_stop_queue(drive->queue);
 241         } else {
 242                 drive->blocked = 0;
 243                 blk_start_queue(drive->queue);
 244         }
 245         blkdev_dequeue_request(rq);
 246         HWGROUP(drive)->rq = NULL;
 247         end_that_request_last(rq, 1);
 248         spin_unlock_irqrestore(&ide_lock, flags);
 249 }
 250
 251 /*
 252  * FIXME: probably move this somewhere else, name is bad too :)
 253  */
 254 u64 ide_get_error_location(ide_drive_t *drive, char *args)
 255 {
 256         u32 high, low;
 257         u8 hcyl, lcyl, sect;
 258         u64 sector;
 259
 260         high = 0;
 261         hcyl = args[5];
 262         lcyl = args[4];
 263         sect = args[3];
 264
 265         if (ide_id_has_flush_cache_ext(drive->id)) {
 266                 low = (hcyl << 16) | (lcyl << 8) | sect;
 267                 HWIF(drive)->OUTB(drive->ctl|0x80, IDE_CONTROL_REG);
 268                 high = ide_read_24(drive);
 269         } else {
 270                 u8 cur = HWIF(drive)->INB(IDE_SELECT_REG);
 271                 if (cur & 0x40) {
 272                         high = cur & 0xf;
 273                         low = (hcyl << 16) | (lcyl << 8) | sect;
 274                 } else {
 275                         low = hcyl * drive->head * drive->sect;
 276                         low += lcyl * drive->sect;
 277                         low += sect - 1;
 278                 }
 279         }
 280
 281         sector = ((u64) high << 24) | low;
 282         return sector;
 283 }
 284 EXPORT_SYMBOL(ide_get_error_location);
 285
 286 /**
 287  *      ide_end_drive_cmd       -       end an explicit drive command
 288  *      @drive: command
 289  *      @stat: status bits
 290  *      @err: error bits
 291  *
 292  *      Clean up after success/failure of an explicit drive command.
 293  *      These get thrown onto the queue so they are synchronized with
 294  *      real I/O operations on the drive.
 295  *
 296  *      In LBA48 mode we have to read the register set twice to get
 297  *      all the extra information out.
 298  */
 299
 300 void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err)
 301 {
 302         ide_hwif_t *hwif = HWIF(drive);
 303         unsigned long flags;
 304         struct request *rq;
 305
 306         spin_lock_irqsave(&ide_lock, flags);
 307         rq = HWGROUP(drive)->rq;
 308         spin_unlock_irqrestore(&ide_lock, flags);
 309
 310         if (rq->flags & REQ_DRIVE_CMD) {
 311                 u8 *args = (u8 *) rq->buffer;
 312                 if (rq->errors == 0)
 313                         rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
 314
 315                 if (args) {
 316                         args[0] = stat;
 317                         args[1] = err;
 318                         args[2] = hwif->INB(IDE_NSECTOR_REG);
 319                 }
 320         } else if (rq->flags & REQ_DRIVE_TASK) {
 321                 u8 *args = (u8 *) rq->buffer;
 322                 if (rq->errors == 0)
 323                         rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
 324
 325                 if (args) {
 326                         args[0] = stat;
 327                         args[1] = err;
 328                         args[2] = hwif->INB(IDE_NSECTOR_REG);
 329                         args[3] = hwif->INB(IDE_SECTOR_REG);
 330                         args[4] = hwif->INB(IDE_LCYL_REG);
 331                         args[5] = hwif->INB(IDE_HCYL_REG);
 332                         args[6] = hwif->INB(IDE_SELECT_REG);
 333                 }
 334         } else if (rq->flags & REQ_DRIVE_TASKFILE) {
 335                 ide_task_t *args = (ide_task_t *) rq->special;
 336                 if (rq->errors == 0)
 337                         rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
 338
 339                 if (args) {
 340                         if (args->tf_in_flags.b.data) {
 341                                 u16 data                                = hwif->INW(IDE_DATA_REG);
 342                                 args->tfRegister[IDE_DATA_OFFSET]       = (data) & 0xFF;
 343                                 args->hobRegister[IDE_DATA_OFFSET]      = (data >> 8) & 0xFF;
 344                         }
 345                         args->tfRegister[IDE_ERROR_OFFSET]   = err;
 346                         /* be sure we're looking at the low order bits */
 347                         hwif->OUTB(drive->ctl & ~0x80, IDE_CONTROL_REG);
 348                         args->tfRegister[IDE_NSECTOR_OFFSET] = hwif->INB(IDE_NSECTOR_REG);
 349                         args->tfRegister[IDE_SECTOR_OFFSET]  = hwif->INB(IDE_SECTOR_REG);
 350                         args->tfRegister[IDE_LCYL_OFFSET]    = hwif->INB(IDE_LCYL_REG);
 351                         args->tfRegister[IDE_HCYL_OFFSET]    = hwif->INB(IDE_HCYL_REG);
 352                         args->tfRegister[IDE_SELECT_OFFSET]  = hwif->INB(IDE_SELECT_REG);
 353                         args->tfRegister[IDE_STATUS_OFFSET]  = stat;
 354
 355                         if (drive->addressing == 1) {
 356                                 hwif->OUTB(drive->ctl|0x80, IDE_CONTROL_REG);
 357                                 args->hobRegister[IDE_FEATURE_OFFSET]   = hwif->INB(IDE_FEATURE_REG);
 358                                 args->hobRegister[IDE_NSECTOR_OFFSET]   = hwif->INB(IDE_NSECTOR_REG);
 359                                 args->hobRegister[IDE_SECTOR_OFFSET]    = hwif->INB(IDE_SECTOR_REG);
 360                                 args->hobRegister[IDE_LCYL_OFFSET]      = hwif->INB(IDE_LCYL_REG);
 361                                 args->hobRegister[IDE_HCYL_OFFSET]      = hwif->INB(IDE_HCYL_REG);
 362                         }
 363                 }
 364         } else if (blk_pm_request(rq)) {
 365 #ifdef DEBUG_PM
 366                 printk("%s: complete_power_step(step: %d, stat: %x, err: %x)\n",
 367                         drive->name, rq->pm->pm_step, stat, err);
 368 #endif
 369                 ide_complete_power_step(drive, rq, stat, err);
 370                 if (rq->pm->pm_step == ide_pm_state_completed)
 371                         ide_complete_pm_request(drive, rq);
 372                 return;
 373         }
 374
 375         spin_lock_irqsave(&ide_lock, flags);
 376         blkdev_dequeue_request(rq);
 377         HWGROUP(drive)->rq = NULL;
 378         rq->errors = err;
 379         end_that_request_last(rq, !rq->errors);
 380         spin_unlock_irqrestore(&ide_lock, flags);
 381 }
 382
 383 EXPORT_SYMBOL(ide_end_drive_cmd);
 384
 385 /**
 386  *      try_to_flush_leftover_data      -       flush junk
 387  *      @drive: drive to flush
 388  *
 389  *      try_to_flush_leftover_data() is invoked in response to a drive
 390  *      unexpectedly having its DRQ_STAT bit set.  As an alternative to
 391  *      resetting the drive, this routine tries to clear the condition
 392  *      by read a sector's worth of data from the drive.  Of course,
 393  *      this may not help if the drive is *waiting* for data from *us*.
 394  */
 395 static void try_to_flush_leftover_data (ide_drive_t *drive)
 396 {
 397         int i = (drive->mult_count ? drive->mult_count : 1) * SECTOR_WORDS;
 398
 399         if (drive->media != ide_disk)
 400                 return;
 401         while (i > 0) {
 402                 u32 buffer[16];
 403                 u32 wcount = (i > 16) ? 16 : i;
 404
 405                 i -= wcount;
 406                 HWIF(drive)->ata_input_data(drive, buffer, wcount);
 407         }
 408 }
 409
 410 static void ide_kill_rq(ide_drive_t *drive, struct request *rq)
 411 {
 412         if (rq->rq_disk) {
 413                 ide_driver_t *drv;
 414
 415                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
 416                 drv->end_request(drive, 0, 0);
 417         } else
 418                 ide_end_request(drive, 0, 0);
 419 }
 420
 421 static ide_startstop_t ide_ata_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
 422 {
 423         ide_hwif_t *hwif = drive->hwif;
 424
 425         if (stat & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) {
 426                 /* other bits are useless when BUSY */
 427                 rq->errors |= ERROR_RESET;
 428         } else if (stat & ERR_STAT) {
 429                 /* err has different meaning on cdrom and tape */
 430                 if (err == ABRT_ERR) {
 431                         if (drive->select.b.lba &&
 432                             /* some newer drives don't support WIN_SPECIFY */
 433                             hwif->INB(IDE_COMMAND_REG) == WIN_SPECIFY)
 434                                 return ide_stopped;
 435                 } else if ((err & BAD_CRC) == BAD_CRC) {
 436                         /* UDMA crc error, just retry the operation */
 437                         drive->crc_count++;
 438                 } else if (err & (BBD_ERR | ECC_ERR)) {
 439                         /* retries won't help these */
 440                         rq->errors = ERROR_MAX;
 441                 } else if (err & TRK0_ERR) {
 442                         /* help it find track zero */
 443                         rq->errors |= ERROR_RECAL;
 444                 }
 445         }
 446
 447         if ((stat & DRQ_STAT) && rq_data_dir(rq) == READ)
 448                 try_to_flush_leftover_data(drive);
 449
 450         if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT))
 451                 /* force an abort */
 452                 hwif->OUTB(WIN_IDLEIMMEDIATE, IDE_COMMAND_REG);
 453
 454         if (rq->errors >= ERROR_MAX || blk_noretry_request(rq))
 455                 ide_kill_rq(drive, rq);
 456         else {
 457                 if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
 458                         ++rq->errors;
 459                         return ide_do_reset(drive);
 460                 }
 461                 if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
 462                         drive->special.b.recalibrate = 1;
 463                 ++rq->errors;
 464         }
 465         return ide_stopped;
 466 }
 467
 468 static ide_startstop_t ide_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
 469 {
 470         ide_hwif_t *hwif = drive->hwif;
 471
 472         if (stat & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) {
 473                 /* other bits are useless when BUSY */
 474                 rq->errors |= ERROR_RESET;
 475         } else {
 476                 /* add decoding error stuff */
 477         }
 478
 479         if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT))
 480                 /* force an abort */
 481                 hwif->OUTB(WIN_IDLEIMMEDIATE, IDE_COMMAND_REG);
 482
 483         if (rq->errors >= ERROR_MAX) {
 484                 ide_kill_rq(drive, rq);
 485         } else {
 486                 if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
 487                         ++rq->errors;
 488                         return ide_do_reset(drive);
 489                 }
 490                 ++rq->errors;
 491         }
 492
 493         return ide_stopped;
 494 }
 495
 496 ide_startstop_t
 497 __ide_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
 498 {
 499         if (drive->media == ide_disk)
 500                 return ide_ata_error(drive, rq, stat, err);
 501         return ide_atapi_error(drive, rq, stat, err);
 502 }
 503
 504 EXPORT_SYMBOL_GPL(__ide_error);
 505
 506 /**
 507  *      ide_error       -       handle an error on the IDE
 508  *      @drive: drive the error occurred on
 509  *      @msg: message to report
 510  *      @stat: status bits
 511  *
 512  *      ide_error() takes action based on the error returned by the drive.
 513  *      For normal I/O that may well include retries. We deal with
 514  *      both new-style (taskfile) and old style command handling here.
 515  *      In the case of taskfile command handling there is work left to
 516  *      do
 517  */
 518
 519 ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat)
 520 {
 521         struct request *rq;
 522         u8 err;
 523
 524         err = ide_dump_status(drive, msg, stat);
 525
 526         if ((rq = HWGROUP(drive)->rq) == NULL)
 527                 return ide_stopped;
 528
 529         /* retry only "normal" I/O: */
 530         if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK | REQ_DRIVE_TASKFILE)) {
 531                 rq->errors = 1;
 532                 ide_end_drive_cmd(drive, stat, err);
 533                 return ide_stopped;
 534         }
 535
 536         if (rq->rq_disk) {
 537                 ide_driver_t *drv;
 538
 539                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
 540                 return drv->error(drive, rq, stat, err);
 541         } else
 542                 return __ide_error(drive, rq, stat, err);
 543 }
 544
 545 EXPORT_SYMBOL_GPL(ide_error);
 546
 547 ide_startstop_t __ide_abort(ide_drive_t *drive, struct request *rq)
 548 {
 549         if (drive->media != ide_disk)
 550                 rq->errors |= ERROR_RESET;
 551
 552         ide_kill_rq(drive, rq);
 553
 554         return ide_stopped;
 555 }
 556
 557 EXPORT_SYMBOL_GPL(__ide_abort);
 558
 559 /**
 560  *      ide_abort       -       abort pending IDE operations
 561  *      @drive: drive the error occurred on
 562  *      @msg: message to report
 563  *
 564  *      ide_abort kills and cleans up when we are about to do a
 565  *      host initiated reset on active commands. Longer term we
 566  *      want handlers to have sensible abort handling themselves
 567  *
 568  *      This differs fundamentally from ide_error because in
 569  *      this case the command is doing just fine when we
 570  *      blow it away.
 571  */
 572
 573 ide_startstop_t ide_abort(ide_drive_t *drive, const char *msg)
 574 {
 575         struct request *rq;
 576
 577         if (drive == NULL || (rq = HWGROUP(drive)->rq) == NULL)
 578                 return ide_stopped;
 579
 580         /* retry only "normal" I/O: */
 581         if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK | REQ_DRIVE_TASKFILE)) {
 582                 rq->errors = 1;
 583                 ide_end_drive_cmd(drive, BUSY_STAT, 0);
 584                 return ide_stopped;
 585         }
 586
 587         if (rq->rq_disk) {
 588                 ide_driver_t *drv;
 589
 590                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
 591                 return drv->abort(drive, rq);
 592         } else
 593                 return __ide_abort(drive, rq);
 594 }
 595
 596 /**
 597  *      ide_cmd         -       issue a simple drive command
 598  *      @drive: drive the command is for
 599  *      @cmd: command byte
 600  *      @nsect: sector byte
 601  *      @handler: handler for the command completion
 602  *
 603  *      Issue a simple drive command with interrupts.
 604  *      The drive must be selected beforehand.
 605  */
 606
 607 static void ide_cmd (ide_drive_t *drive, u8 cmd, u8 nsect,
 608                 ide_handler_t *handler)
 609 {
 610         ide_hwif_t *hwif = HWIF(drive);
 611         if (IDE_CONTROL_REG)
 612                 hwif->OUTB(drive->ctl,IDE_CONTROL_REG); /* clear nIEN */
 613         SELECT_MASK(drive,0);
 614         hwif->OUTB(nsect,IDE_NSECTOR_REG);
 615         ide_execute_command(drive, cmd, handler, WAIT_CMD, NULL);
 616 }
 617
 618 /**
 619  *      drive_cmd_intr          -       drive command completion interrupt
 620  *      @drive: drive the completion interrupt occurred on
 621  *
 622  *      drive_cmd_intr() is invoked on completion of a special DRIVE_CMD.
 623  *      We do any necessary data reading and then wait for the drive to
 624  *      go non busy. At that point we may read the error data and complete
 625  *      the request
 626  */
 627
 628 static ide_startstop_t drive_cmd_intr (ide_drive_t *drive)
 629 {
 630         struct request *rq = HWGROUP(drive)->rq;
 631         ide_hwif_t *hwif = HWIF(drive);
 632         u8 *args = (u8 *) rq->buffer;
 633         u8 stat = hwif->INB(IDE_STATUS_REG);
 634         int retries = 10;
 635
 636         local_irq_enable();
 637         if ((stat & DRQ_STAT) && args && args[3]) {
 638                 u8 io_32bit = drive->io_32bit;
 639                 drive->io_32bit = 0;
 640                 hwif->ata_input_data(drive, &args[4], args[3] * SECTOR_WORDS);
 641                 drive->io_32bit = io_32bit;
 642                 while (((stat = hwif->INB(IDE_STATUS_REG)) & BUSY_STAT) && retries--)
 643                         udelay(100);
 644         }
 645
 646         if (!OK_STAT(stat, READY_STAT, BAD_STAT))
 647                 return ide_error(drive, "drive_cmd", stat);
 648                 /* calls ide_end_drive_cmd */
 649         ide_end_drive_cmd(drive, stat, hwif->INB(IDE_ERROR_REG));
 650         return ide_stopped;
 651 }
 652
 653 static void ide_init_specify_cmd(ide_drive_t *drive, ide_task_t *task)
 654 {
 655         task->tfRegister[IDE_NSECTOR_OFFSET] = drive->sect;
 656         task->tfRegister[IDE_SECTOR_OFFSET]  = drive->sect;
 657         task->tfRegister[IDE_LCYL_OFFSET]    = drive->cyl;
 658         task->tfRegister[IDE_HCYL_OFFSET]    = drive->cyl>>8;
 659         task->tfRegister[IDE_SELECT_OFFSET]  = ((drive->head-1)|drive->select.all)&0xBF;
 660         task->tfRegister[IDE_COMMAND_OFFSET] = WIN_SPECIFY;
 661
 662         task->handler = &set_geometry_intr;
 663 }
 664
 665 static void ide_init_restore_cmd(ide_drive_t *drive, ide_task_t *task)
 666 {
 667         task->tfRegister[IDE_NSECTOR_OFFSET] = drive->sect;
 668         task->tfRegister[IDE_COMMAND_OFFSET] = WIN_RESTORE;
 669
 670         task->handler = &recal_intr;
 671 }
 672
 673 static void ide_init_setmult_cmd(ide_drive_t *drive, ide_task_t *task)
 674 {
 675         task->tfRegister[IDE_NSECTOR_OFFSET] = drive->mult_req;
 676         task->tfRegister[IDE_COMMAND_OFFSET] = WIN_SETMULT;
 677
 678         task->handler = &set_multmode_intr;
 679 }
 680
 681 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
 682 {
 683         special_t *s = &drive->special;
 684         ide_task_t args;
 685
 686         memset(&args, 0, sizeof(ide_task_t));
 687         args.command_type = IDE_DRIVE_TASK_NO_DATA;
 688
 689         if (s->b.set_geometry) {
 690                 s->b.set_geometry = 0;
 691                 ide_init_specify_cmd(drive, &args);
 692         } else if (s->b.recalibrate) {
 693                 s->b.recalibrate = 0;
 694                 ide_init_restore_cmd(drive, &args);
 695         } else if (s->b.set_multmode) {
 696                 s->b.set_multmode = 0;
 697                 if (drive->mult_req > drive->id->max_multsect)
 698                         drive->mult_req = drive->id->max_multsect;
 699                 ide_init_setmult_cmd(drive, &args);
 700         } else if (s->all) {
 701                 int special = s->all;
 702                 s->all = 0;
 703                 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
 704                 return ide_stopped;
 705         }
 706
 707         do_rw_taskfile(drive, &args);
 708
 709         return ide_started;
 710 }
 711
 712 /**
 713  *      do_special              -       issue some special commands
 714  *      @drive: drive the command is for
 715  *
 716  *      do_special() is used to issue WIN_SPECIFY, WIN_RESTORE, and WIN_SETMULT
 717  *      commands to a drive.  It used to do much more, but has been scaled
 718  *      back.
 719  */
 720
 721 static ide_startstop_t do_special (ide_drive_t *drive)
 722 {
 723         special_t *s = &drive->special;
 724
 725 #ifdef DEBUG
 726         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
 727 #endif
 728         if (s->b.set_tune) {
 729                 s->b.set_tune = 0;
 730                 if (HWIF(drive)->tuneproc != NULL)
 731                         HWIF(drive)->tuneproc(drive, drive->tune_req);
 732                 return ide_stopped;
 733         } else {
 734                 if (drive->media == ide_disk)
 735                         return ide_disk_special(drive);
 736
 737                 s->all = 0;
 738                 drive->mult_req = 0;
 739                 return ide_stopped;
 740         }
 741 }
 742
 743 void ide_map_sg(ide_drive_t *drive, struct request *rq)
 744 {
 745         ide_hwif_t *hwif = drive->hwif;
 746         struct scatterlist *sg = hwif->sg_table;
 747
 748         if (hwif->sg_mapped)    /* needed by ide-scsi */
 749                 return;
 750
 751         if ((rq->flags & REQ_DRIVE_TASKFILE) == 0) {
 752                 hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
 753         } else {
 754                 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
 755                 hwif->sg_nents = 1;
 756         }
 757 }
 758
 759 EXPORT_SYMBOL_GPL(ide_map_sg);
 760
 761 void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq)
 762 {
 763         ide_hwif_t *hwif = drive->hwif;
 764
 765         hwif->nsect = hwif->nleft = rq->nr_sectors;
 766         hwif->cursg = hwif->cursg_ofs = 0;
 767 }
 768
 769 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 770
 771 /**
 772  *      execute_drive_command   -       issue special drive command
 773  *      @drive: the drive to issue the command on
 774  *      @rq: the request structure holding the command
 775  *
 776  *      execute_drive_cmd() issues a special drive command,  usually
 777  *      initiated by ioctl() from the external hdparm program. The
 778  *      command can be a drive command, drive task or taskfile
 779  *      operation. Weirdly you can call it with NULL to wait for
 780  *      all commands to finish. Don't do this as that is due to change
 781  */
 782
 783 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
 784                 struct request *rq)
 785 {
 786         ide_hwif_t *hwif = HWIF(drive);
 787         if (rq->flags & REQ_DRIVE_TASKFILE) {
 788                 ide_task_t *args = rq->special;
 789
 790                 if (!args)
 791                         goto done;
 792
 793                 hwif->data_phase = args->data_phase;
 794
 795                 switch (hwif->data_phase) {
 796                 case TASKFILE_MULTI_OUT:
 797                 case TASKFILE_OUT:
 798                 case TASKFILE_MULTI_IN:
 799                 case TASKFILE_IN:
 800                         ide_init_sg_cmd(drive, rq);
 801                         ide_map_sg(drive, rq);
 802                 default:
 803                         break;
 804                 }
 805
 806                 if (args->tf_out_flags.all != 0)
 807                         return flagged_taskfile(drive, args);
 808                 return do_rw_taskfile(drive, args);
 809         } else if (rq->flags & REQ_DRIVE_TASK) {
 810                 u8 *args = rq->buffer;
 811                 u8 sel;
 812
 813                 if (!args)
 814                         goto done;
 815 #ifdef DEBUG
 816                 printk("%s: DRIVE_TASK_CMD ", drive->name);
 817                 printk("cmd=0x%02x ", args[0]);
 818                 printk("fr=0x%02x ", args[1]);
 819                 printk("ns=0x%02x ", args[2]);
 820                 printk("sc=0x%02x ", args[3]);
 821                 printk("lcyl=0x%02x ", args[4]);
 822                 printk("hcyl=0x%02x ", args[5]);
 823                 printk("sel=0x%02x\n", args[6]);
 824 #endif
 825                 hwif->OUTB(args[1], IDE_FEATURE_REG);
 826                 hwif->OUTB(args[3], IDE_SECTOR_REG);
 827                 hwif->OUTB(args[4], IDE_LCYL_REG);
 828                 hwif->OUTB(args[5], IDE_HCYL_REG);
 829                 sel = (args[6] & ~0x10);
 830                 if (drive->select.b.unit)
 831                         sel |= 0x10;
 832                 hwif->OUTB(sel, IDE_SELECT_REG);
 833                 ide_cmd(drive, args[0], args[2], &drive_cmd_intr);
 834                 return ide_started;
 835         } else if (rq->flags & REQ_DRIVE_CMD) {
 836                 u8 *args = rq->buffer;
 837
 838                 if (!args)
 839                         goto done;
 840 #ifdef DEBUG
 841                 printk("%s: DRIVE_CMD ", drive->name);
 842                 printk("cmd=0x%02x ", args[0]);
 843                 printk("sc=0x%02x ", args[1]);
 844                 printk("fr=0x%02x ", args[2]);
 845                 printk("xx=0x%02x\n", args[3]);
 846 #endif
 847                 if (args[0] == WIN_SMART) {
 848                         hwif->OUTB(0x4f, IDE_LCYL_REG);
 849                         hwif->OUTB(0xc2, IDE_HCYL_REG);
 850                         hwif->OUTB(args[2],IDE_FEATURE_REG);
 851                         hwif->OUTB(args[1],IDE_SECTOR_REG);
 852                         ide_cmd(drive, args[0], args[3], &drive_cmd_intr);
 853                         return ide_started;
 854                 }
 855                 hwif->OUTB(args[2],IDE_FEATURE_REG);
 856                 ide_cmd(drive, args[0], args[1], &drive_cmd_intr);
 857                 return ide_started;
 858         }
 859
 860 done:
 861         /*
 862          * NULL is actually a valid way of waiting for
 863          * all current requests to be flushed from the queue.
 864          */
 865 #ifdef DEBUG
 866         printk("%s: DRIVE_CMD (null)\n", drive->name);
 867 #endif
 868         ide_end_drive_cmd(drive,
 869                         hwif->INB(IDE_STATUS_REG),
 870                         hwif->INB(IDE_ERROR_REG));
 871         return ide_stopped;
 872 }
 873
 874 /**
 875  *      start_request   -       start of I/O and command issuing for IDE
 876  *
 877  *      start_request() initiates handling of a new I/O request. It
 878  *      accepts commands and I/O (read/write) requests. It also does
 879  *      the final remapping for weird stuff like EZDrive. Once
 880  *      device mapper can work sector level the EZDrive stuff can go away
 881  *
 882  *      FIXME: this function needs a rename
 883  */
 884
 885 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 886 {
 887         ide_startstop_t startstop;
 888         sector_t block;
 889
 890         BUG_ON(!(rq->flags & REQ_STARTED));
 891
 892 #ifdef DEBUG
 893         printk("%s: start_request: current=0x%08lx\n",
 894                 HWIF(drive)->name, (unsigned long) rq);
 895 #endif
 896
 897         /* bail early if we've exceeded max_failures */
 898         if (drive->max_failures && (drive->failures > drive->max_failures)) {
 899                 goto kill_rq;
 900         }
 901
 902         block    = rq->sector;
 903         if (blk_fs_request(rq) &&
 904             (drive->media == ide_disk || drive->media == ide_floppy)) {
 905                 block += drive->sect0;
 906         }
 907         /* Yecch - this will shift the entire interval,
 908            possibly killing some innocent following sector */
 909         if (block == 0 && drive->remap_0_to_1 == 1)
 910                 block = 1;  /* redirect MBR access to EZ-Drive partn table */
 911
 912         if (blk_pm_suspend_request(rq) &&
 913             rq->pm->pm_step == ide_pm_state_start_suspend)
 914                 /* Mark drive blocked when starting the suspend sequence. */
 915                 drive->blocked = 1;
 916         else if (blk_pm_resume_request(rq) &&
 917                  rq->pm->pm_step == ide_pm_state_start_resume) {
 918                 /*
 919                  * The first thing we do on wakeup is to wait for BSY bit to
 920                  * go away (with a looong timeout) as a drive on this hwif may
 921                  * just be POSTing itself.
 922                  * We do that before even selecting as the "other" device on
 923                  * the bus may be broken enough to walk on our toes at this
 924                  * point.
 925                  */
 926                 int rc;
 927 #ifdef DEBUG_PM
 928                 printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
 929 #endif
 930                 rc = ide_wait_not_busy(HWIF(drive), 35000);
 931                 if (rc)
 932                         printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
 933                 SELECT_DRIVE(drive);
 934                 HWIF(drive)->OUTB(8, HWIF(drive)->io_ports[IDE_CONTROL_OFFSET]);
 935                 rc = ide_wait_not_busy(HWIF(drive), 100000);
 936                 if (rc)
 937                         printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
 938         }
 939
 940         SELECT_DRIVE(drive);
 941         if (ide_wait_stat(&startstop, drive, drive->ready_stat, BUSY_STAT|DRQ_STAT, WAIT_READY)) {
 942                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 943                 return startstop;
 944         }
 945         if (!drive->special.all) {
 946                 ide_driver_t *drv;
 947
 948                 if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK))
 949                         return execute_drive_cmd(drive, rq);
 950                 else if (rq->flags & REQ_DRIVE_TASKFILE)
 951                         return execute_drive_cmd(drive, rq);
 952                 else if (blk_pm_request(rq)) {
 953 #ifdef DEBUG_PM
 954                         printk("%s: start_power_step(step: %d)\n",
 955                                 drive->name, rq->pm->pm_step);
 956 #endif
 957                         startstop = ide_start_power_step(drive, rq);
 958                         if (startstop == ide_stopped &&
 959                             rq->pm->pm_step == ide_pm_state_completed)
 960                                 ide_complete_pm_request(drive, rq);
 961                         return startstop;
 962                 }
 963
 964                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
 965                 return drv->do_request(drive, rq, block);
 966         }
 967         return do_special(drive);
 968 kill_rq:
 969         ide_kill_rq(drive, rq);
 970         return ide_stopped;
 971 }
 972
 973 /**
 974  *      ide_stall_queue         -       pause an IDE device
 975  *      @drive: drive to stall
 976  *      @timeout: time to stall for (jiffies)
 977  *
 978  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 979  *      to the hwgroup by sleeping for timeout jiffies.
 980  */
 981
 982 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 983 {
 984         if (timeout > WAIT_WORSTCASE)
 985                 timeout = WAIT_WORSTCASE;
 986         drive->sleep = timeout + jiffies;
 987         drive->sleeping = 1;
 988 }
 989
 990 EXPORT_SYMBOL(ide_stall_queue);
 991
 992 #define WAKEUP(drive)   ((drive)->service_start + 2 * (drive)->service_time)
 993
 994 /**
 995  *      choose_drive            -       select a drive to service
 996  *      @hwgroup: hardware group to select on
 997  *
 998  *      choose_drive() selects the next drive which will be serviced.
 999  *      This is necessary because the IDE layer can't issue commands
1000  *      to both drives on the same cable, unlike SCSI.
1001  */
1002
1003 static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
1004 {
1005         ide_drive_t *drive, *best;
1006
1007 repeat:
1008         best = NULL;
1009         drive = hwgroup->drive;
1010
1011         /*
1012          * drive is doing pre-flush, ordered write, post-flush sequence. even
1013          * though that is 3 requests, it must be seen as a single transaction.
1014          * we must not preempt this drive until that is complete
1015          */
1016         if (blk_queue_flushing(drive->queue)) {
1017                 /*
1018                  * small race where queue could get replugged during
1019                  * the 3-request flush cycle, just yank the plug since
1020                  * we want it to finish asap
1021                  */
1022                 blk_remove_plug(drive->queue);
1023                 return drive;
1024         }
1025
1026         do {
1027                 if ((!drive->sleeping || time_after_eq(jiffies, drive->sleep))
1028                     && !elv_queue_empty(drive->queue)) {
1029                         if (!best
1030                          || (drive->sleeping && (!best->sleeping || time_before(drive->sleep, best->sleep)))
1031                          || (!best->sleeping && time_before(WAKEUP(drive), WAKEUP(best))))
1032                         {
1033                                 if (!blk_queue_plugged(drive->queue))
1034                                         best = drive;
1035                         }
1036                 }
1037         } while ((drive = drive->next) != hwgroup->drive);
1038         if (best && best->nice1 && !best->sleeping && best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
1039                 long t = (signed long)(WAKEUP(best) - jiffies);
1040                 if (t >= WAIT_MIN_SLEEP) {
1041                 /*
1042                  * We *may* have some time to spare, but first let's see if
1043                  * someone can potentially benefit from our nice mood today..
1044                  */
1045                         drive = best->next;
1046                         do {
1047                                 if (!drive->sleeping
1048                                  && time_before(jiffies - best->service_time, WAKEUP(drive))
1049                                  && time_before(WAKEUP(drive), jiffies + t))
1050                                 {
1051                                         ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP));
1052                                         goto repeat;
1053                                 }
1054                         } while ((drive = drive->next) != best);
1055                 }
1056         }
1057         return best;
1058 }
1059
1060 /*
1061  * Issue a new request to a drive from hwgroup
1062  * Caller must have already done spin_lock_irqsave(&ide_lock, ..);
1063  *
1064  * A hwgroup is a serialized group of IDE interfaces.  Usually there is
1065  * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640)
1066  * may have both interfaces in a single hwgroup to "serialize" access.
1067  * Or possibly multiple ISA interfaces can share a common IRQ by being grouped
1068  * together into one hwgroup for serialized access.
1069  *
1070  * Note also that several hwgroups can end up sharing a single IRQ,
1071  * possibly along with many other devices.  This is especially common in
1072  * PCI-based systems with off-board IDE controller cards.
1073  *
1074  * The IDE driver uses the single global ide_lock spinlock to protect
1075  * access to the request queues, and to protect the hwgroup->busy flag.
1076  *
1077  * The first thread into the driver for a particular hwgroup sets the
1078  * hwgroup->busy flag to indicate that this hwgroup is now active,
1079  * and then initiates processing of the top request from the request queue.
1080  *
1081  * Other threads attempting entry notice the busy setting, and will simply
1082  * queue their new requests and exit immediately.  Note that hwgroup->busy
1083  * remains set even when the driver is merely awaiting the next interrupt.
1084  * Thus, the meaning is "this hwgroup is busy processing a request".
1085  *
1086  * When processing of a request completes, the completing thread or IRQ-handler
1087  * will start the next request from the queue.  If no more work remains,
1088  * the driver will clear the hwgroup->busy flag and exit.
1089  *
1090  * The ide_lock (spinlock) is used to protect all access to the
1091  * hwgroup->busy flag, but is otherwise not needed for most processing in
1092  * the driver.  This makes the driver much more friendlier to shared IRQs
1093  * than previous designs, while remaining 100% (?) SMP safe and capable.
1094  */
1095 static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
1096 {
1097         ide_drive_t     *drive;
1098         ide_hwif_t      *hwif;
1099         struct request  *rq;
1100         ide_startstop_t startstop;
1101         int             loops = 0;
1102
1103         /* for atari only: POSSIBLY BROKEN HERE(?) */
1104         ide_get_lock(ide_intr, hwgroup);
1105
1106         /* caller must own ide_lock */
1107         BUG_ON(!irqs_disabled());
1108
1109         while (!hwgroup->busy) {
1110                 hwgroup->busy = 1;
1111                 drive = choose_drive(hwgroup);
1112                 if (drive == NULL) {
1113                         int sleeping = 0;
1114                         unsigned long sleep = 0; /* shut up, gcc */
1115                         hwgroup->rq = NULL;
1116                         drive = hwgroup->drive;
1117                         do {
1118                                 if (drive->sleeping && (!sleeping || time_before(drive->sleep, sleep))) {
1119                                         sleeping = 1;
1120                                         sleep = drive->sleep;
1121                                 }
1122                         } while ((drive = drive->next) != hwgroup->drive);
1123                         if (sleeping) {
1124                 /*
1125                  * Take a short snooze, and then wake up this hwgroup again.
1126                  * This gives other hwgroups on the same a chance to
1127                  * play fairly with us, just in case there are big differences
1128                  * in relative throughputs.. don't want to hog the cpu too much.
1129                  */
1130                                 if (time_before(sleep, jiffies + WAIT_MIN_SLEEP))
1131                                         sleep = jiffies + WAIT_MIN_SLEEP;
1132 #if 1
1133                                 if (timer_pending(&hwgroup->timer))
1134                                         printk(KERN_CRIT "ide_set_handler: timer already active\n");
1135 #endif
1136                                 /* so that ide_timer_expiry knows what to do */
1137                                 hwgroup->sleeping = 1;
1138                                 mod_timer(&hwgroup->timer, sleep);
1139                                 /* we purposely leave hwgroup->busy==1
1140                                  * while sleeping */
1141                         } else {
1142                                 /* Ugly, but how can we sleep for the lock
1143                                  * otherwise? perhaps from tq_disk?
1144                                  */
1145
1146                                 /* for atari only */
1147                                 ide_release_lock();
1148                                 hwgroup->busy = 0;
1149                         }
1150
1151                         /* no more work for this hwgroup (for now) */
1152                         return;
1153                 }
1154         again:
1155                 hwif = HWIF(drive);
1156                 if (hwgroup->hwif->sharing_irq &&
1157                     hwif != hwgroup->hwif &&
1158                     hwif->io_ports[IDE_CONTROL_OFFSET]) {
1159                         /* set nIEN for previous hwif */
1160                         SELECT_INTERRUPT(drive);
1161                 }
1162                 hwgroup->hwif = hwif;
1163                 hwgroup->drive = drive;
1164                 drive->sleeping = 0;
1165                 drive->service_start = jiffies;
1166
1167                 if (blk_queue_plugged(drive->queue)) {
1168                         printk(KERN_ERR "ide: huh? queue was plugged!\n");
1169                         break;
1170                 }
1171
1172                 /*
1173                  * we know that the queue isn't empty, but this can happen
1174                  * if the q->prep_rq_fn() decides to kill a request
1175                  */
1176                 rq = elv_next_request(drive->queue);
1177                 if (!rq) {
1178                         hwgroup->busy = 0;
1179                         break;
1180                 }
1181
1182                 /*
1183                  * Sanity: don't accept a request that isn't a PM request
1184                  * if we are currently power managed. This is very important as
1185                  * blk_stop_queue() doesn't prevent the elv_next_request()
1186                  * above to return us whatever is in the queue. Since we call
1187                  * ide_do_request() ourselves, we end up taking requests while
1188                  * the queue is blocked...
1189                  *
1190                  * We let requests forced at head of queue with ide-preempt
1191                  * though. I hope that doesn't happen too much, hopefully not
1192                  * unless the subdriver triggers such a thing in its own PM
1193                  * state machine.
1194                  *
1195                  * We count how many times we loop here to make sure we service
1196                  * all drives in the hwgroup without looping for ever
1197                  */
1198                 if (drive->blocked && !blk_pm_request(rq) && !(rq->flags & REQ_PREEMPT)) {
1199                         drive = drive->next ? drive->next : hwgroup->drive;
1200                         if (loops++ < 4 && !blk_queue_plugged(drive->queue))
1201                                 goto again;
1202                         /* We clear busy, there should be no pending ATA command at this point. */
1203                         hwgroup->busy = 0;
1204                         break;
1205                 }
1206
1207                 hwgroup->rq = rq;
1208
1209                 /*
1210                  * Some systems have trouble with IDE IRQs arriving while
1211                  * the driver is still setting things up.  So, here we disable
1212                  * the IRQ used by this interface while the request is being started.
1213                  * This may look bad at first, but pretty much the same thing
1214                  * happens anyway when any interrupt comes in, IDE or otherwise
1215                  *  -- the kernel masks the IRQ while it is being handled.
1216                  */
1217                 if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
1218                         disable_irq_nosync(hwif->irq);
1219                 spin_unlock(&ide_lock);
1220                 local_irq_enable();
1221                         /* allow other IRQs while we start this request */
1222                 startstop = start_request(drive, rq);
1223                 spin_lock_irq(&ide_lock);
1224                 if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
1225                         enable_irq(hwif->irq);
1226                 if (startstop == ide_stopped)
1227                         hwgroup->busy = 0;
1228         }
1229 }
1230
1231 /*
1232  * Passes the stuff to ide_do_request
1233  */
1234 void do_ide_request(request_queue_t *q)
1235 {
1236         ide_drive_t *drive = q->queuedata;
1237
1238         ide_do_request(HWGROUP(drive), IDE_NO_IRQ);
1239 }
1240
1241 /*
1242  * un-busy the hwgroup etc, and clear any pending DMA status. we want to
1243  * retry the current request in pio mode instead of risking tossing it
1244  * all away
1245  */
1246 static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
1247 {
1248         ide_hwif_t *hwif = HWIF(drive);
1249         struct request *rq;
1250         ide_startstop_t ret = ide_stopped;
1251
1252         /*
1253          * end current dma transaction
1254          */
1255
1256         if (error < 0) {
1257                 printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
1258                 (void)HWIF(drive)->ide_dma_end(drive);
1259                 ret = ide_error(drive, "dma timeout error",
1260                                                 hwif->INB(IDE_STATUS_REG));
1261         } else {
1262                 printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
1263                 (void) hwif->ide_dma_timeout(drive);
1264         }
1265
1266         /*
1267          * disable dma for now, but remember that we did so because of
1268          * a timeout -- we'll reenable after we finish this next request
1269          * (or rather the first chunk of it) in pio.
1270          */
1271         drive->retry_pio++;
1272         drive->state = DMA_PIO_RETRY;
1273         (void) hwif->ide_dma_off_quietly(drive);
1274
1275         /*
1276          * un-busy drive etc (hwgroup->busy is cleared on return) and
1277          * make sure request is sane
1278          */
1279         rq = HWGROUP(drive)->rq;
1280         HWGROUP(drive)->rq = NULL;
1281
1282         rq->errors = 0;
1283
1284         if (!rq->bio)
1285                 goto out;
1286
1287         rq->sector = rq->bio->bi_sector;
1288         rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9;
1289         rq->hard_cur_sectors = rq->current_nr_sectors;
1290         rq->buffer = bio_data(rq->bio);
1291 out:
1292         return ret;
1293 }
1294
1295 /**
1296  *      ide_timer_expiry        -       handle lack of an IDE interrupt
1297  *      @data: timer callback magic (hwgroup)
1298  *
1299  *      An IDE command has timed out before the expected drive return
1300  *      occurred. At this point we attempt to clean up the current
1301  *      mess. If the current handler includes an expiry handler then
1302  *      we invoke the expiry handler, and providing it is happy the
1303  *      work is done. If that fails we apply generic recovery rules
1304  *      invoking the handler and checking the drive DMA status. We
1305  *      have an excessively incestuous relationship with the DMA
1306  *      logic that wants cleaning up.
1307  */
1308
1309 void ide_timer_expiry (unsigned long data)
1310 {
1311         ide_hwgroup_t   *hwgroup = (ide_hwgroup_t *) data;
1312         ide_handler_t   *handler;
1313         ide_expiry_t    *expiry;
1314         unsigned long   flags;
1315         unsigned long   wait = -1;
1316
1317         spin_lock_irqsave(&ide_lock, flags);
1318
1319         if ((handler = hwgroup->handler) == NULL) {
1320                 /*
1321                  * Either a marginal timeout occurred
1322                  * (got the interrupt just as timer expired),
1323                  * or we were "sleeping" to give other devices a chance.
1324                  * Either way, we don't really want to complain about anything.
1325                  */
1326                 if (hwgroup->sleeping) {
1327                         hwgroup->sleeping = 0;
1328                         hwgroup->busy = 0;
1329                 }
1330         } else {
1331                 ide_drive_t *drive = hwgroup->drive;
1332                 if (!drive) {
1333                         printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
1334                         hwgroup->handler = NULL;
1335                 } else {
1336                         ide_hwif_t *hwif;
1337                         ide_startstop_t startstop = ide_stopped;
1338                         if (!hwgroup->busy) {
1339                                 hwgroup->busy = 1;      /* paranoia */
1340                                 printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name);
1341                         }
1342                         if ((expiry = hwgroup->expiry) != NULL) {
1343                                 /* continue */
1344                                 if ((wait = expiry(drive)) > 0) {
1345                                         /* reset timer */
1346                                         hwgroup->timer.expires  = jiffies + wait;
1347                                         add_timer(&hwgroup->timer);
1348                                         spin_unlock_irqrestore(&ide_lock, flags);
1349                                         return;
1350                                 }
1351                         }
1352                         hwgroup->handler = NULL;
1353                         /*
1354                          * We need to simulate a real interrupt when invoking
1355                          * the handler() function, which means we need to
1356                          * globally mask the specific IRQ:
1357                          */
1358                         spin_unlock(&ide_lock);
1359                         hwif  = HWIF(drive);
1360 #if DISABLE_IRQ_NOSYNC
1361                         disable_irq_nosync(hwif->irq);
1362 #else
1363                         /* disable_irq_nosync ?? */
1364                         disable_irq(hwif->irq);
1365 #endif /* DISABLE_IRQ_NOSYNC */
1366                         /* local CPU only,
1367                          * as if we were handling an interrupt */
1368                         local_irq_disable();
1369                         if (hwgroup->polling) {
1370                                 startstop = handler(drive);
1371                         } else if (drive_is_ready(drive)) {
1372                                 if (drive->waiting_for_dma)
1373                                         (void) hwgroup->hwif->ide_dma_lostirq(drive);
1374                                 (void)ide_ack_intr(hwif);
1375                                 printk(KERN_WARNING "%s: lost interrupt\n", drive->name);
1376                                 startstop = handler(drive);
1377                         } else {
1378                                 if (drive->waiting_for_dma) {
1379                                         startstop = ide_dma_timeout_retry(drive, wait);
1380                                 } else
1381                                         startstop =
1382                                         ide_error(drive, "irq timeout", hwif->INB(IDE_STATUS_REG));
1383                         }
1384                         drive->service_time = jiffies - drive->service_start;
1385                         spin_lock_irq(&ide_lock);
1386                         enable_irq(hwif->irq);
1387                         if (startstop == ide_stopped)
1388                                 hwgroup->busy = 0;
1389                 }
1390         }
1391         ide_do_request(hwgroup, IDE_NO_IRQ);
1392         spin_unlock_irqrestore(&ide_lock, flags);
1393 }
1394
1395 /**
1396  *      unexpected_intr         -       handle an unexpected IDE interrupt
1397  *      @irq: interrupt line
1398  *      @hwgroup: hwgroup being processed
1399  *
1400  *      There's nothing really useful we can do with an unexpected interrupt,
1401  *      other than reading the status register (to clear it), and logging it.
1402  *      There should be no way that an irq can happen before we're ready for it,
1403  *      so we needn't worry much about losing an "important" interrupt here.
1404  *
1405  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
1406  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
1407  *      looks "good", we just ignore the interrupt completely.
1408  *
1409  *      This routine assumes __cli() is in effect when called.
1410  *
1411  *      If an unexpected interrupt happens on irq15 while we are handling irq14
1412  *      and if the two interfaces are "serialized" (CMD640), then it looks like
1413  *      we could screw up by interfering with a new request being set up for
1414  *      irq15.
1415  *
1416  *      In reality, this is a non-issue.  The new command is not sent unless
1417  *      the drive is ready to accept one, in which case we know the drive is
1418  *      not trying to interrupt us.  And ide_set_handler() is always invoked
1419  *      before completing the issuance of any new drive command, so we will not
1420  *      be accidentally invoked as a result of any valid command completion
1421  *      interrupt.
1422  *
1423  *      Note that we must walk the entire hwgroup here. We know which hwif
1424  *      is doing the current command, but we don't know which hwif burped
1425  *      mysteriously.
1426  */
1427
1428 static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
1429 {
1430         u8 stat;
1431         ide_hwif_t *hwif = hwgroup->hwif;
1432
1433         /*
1434          * handle the unexpected interrupt
1435          */
1436         do {
1437                 if (hwif->irq == irq) {
1438                         stat = hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
1439                         if (!OK_STAT(stat, READY_STAT, BAD_STAT)) {
1440                                 /* Try to not flood the console with msgs */
1441                                 static unsigned long last_msgtime, count;
1442                                 ++count;
1443                                 if (time_after(jiffies, last_msgtime + HZ)) {
1444                                         last_msgtime = jiffies;
1445                                         printk(KERN_ERR "%s%s: unexpected interrupt, "
1446                                                 "status=0x%02x, count=%ld\n",
1447                                                 hwif->name,
1448                                                 (hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count);
1449                                 }
1450                         }
1451                 }
1452         } while ((hwif = hwif->next) != hwgroup->hwif);
1453 }
1454
1455 /**
1456  *      ide_intr        -       default IDE interrupt handler
1457  *      @irq: interrupt number
1458  *      @dev_id: hwif group
1459  *      @regs: unused weirdness from the kernel irq layer
1460  *
1461  *      This is the default IRQ handler for the IDE layer. You should
1462  *      not need to override it. If you do be aware it is subtle in
1463  *      places
1464  *
1465  *      hwgroup->hwif is the interface in the group currently performing
1466  *      a command. hwgroup->drive is the drive and hwgroup->handler is
1467  *      the IRQ handler to call. As we issue a command the handlers
1468  *      step through multiple states, reassigning the handler to the
1469  *      next step in the process. Unlike a smart SCSI controller IDE
1470  *      expects the main processor to sequence the various transfer
1471  *      stages. We also manage a poll timer to catch up with most
1472  *      timeout situations. There are still a few where the handlers
1473  *      don't ever decide to give up.
1474  *
1475  *      The handler eventually returns ide_stopped to indicate the
1476  *      request completed. At this point we issue the next request
1477  *      on the hwgroup and the process begins again.
1478  */
1479
1480 irqreturn_t ide_intr (int irq, void *dev_id, struct pt_regs *regs)
1481 {
1482         unsigned long flags;
1483         ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
1484         ide_hwif_t *hwif;
1485         ide_drive_t *drive;
1486         ide_handler_t *handler;
1487         ide_startstop_t startstop;
1488
1489         spin_lock_irqsave(&ide_lock, flags);
1490         hwif = hwgroup->hwif;
1491
1492         if (!ide_ack_intr(hwif)) {
1493                 spin_unlock_irqrestore(&ide_lock, flags);
1494                 return IRQ_NONE;
1495         }
1496
1497         if ((handler = hwgroup->handler) == NULL || hwgroup->polling) {
1498                 /*
1499                  * Not expecting an interrupt from this drive.
1500                  * That means this could be:
1501                  *      (1) an interrupt from another PCI device
1502                  *      sharing the same PCI INT# as us.
1503                  * or   (2) a drive just entered sleep or standby mode,
1504                  *      and is interrupting to let us know.
1505                  * or   (3) a spurious interrupt of unknown origin.
1506                  *
1507                  * For PCI, we cannot tell the difference,
1508                  * so in that case we just ignore it and hope it goes away.
1509                  *
1510                  * FIXME: unexpected_intr should be hwif-> then we can
1511                  * remove all the ifdef PCI crap
1512                  */
1513 #ifdef CONFIG_BLK_DEV_IDEPCI
1514                 if (hwif->pci_dev && !hwif->pci_dev->vendor)
1515 #endif  /* CONFIG_BLK_DEV_IDEPCI */
1516                 {
1517                         /*
1518                          * Probably not a shared PCI interrupt,
1519                          * so we can safely try to do something about it:
1520                          */
1521                         unexpected_intr(irq, hwgroup);
1522 #ifdef CONFIG_BLK_DEV_IDEPCI
1523                 } else {
1524                         /*
1525                          * Whack the status register, just in case
1526                          * we have a leftover pending IRQ.
1527                          */
1528                         (void) hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
1529 #endif /* CONFIG_BLK_DEV_IDEPCI */
1530                 }
1531                 spin_unlock_irqrestore(&ide_lock, flags);
1532                 return IRQ_NONE;
1533         }
1534         drive = hwgroup->drive;
1535         if (!drive) {
1536                 /*
1537                  * This should NEVER happen, and there isn't much
1538                  * we could do about it here.
1539                  *
1540                  * [Note - this can occur if the drive is hot unplugged]
1541                  */
1542                 spin_unlock_irqrestore(&ide_lock, flags);
1543                 return IRQ_HANDLED;
1544         }
1545         if (!drive_is_ready(drive)) {
1546                 /*
1547                  * This happens regularly when we share a PCI IRQ with
1548                  * another device.  Unfortunately, it can also happen
1549                  * with some buggy drives that trigger the IRQ before
1550                  * their status register is up to date.  Hopefully we have
1551                  * enough advance overhead that the latter isn't a problem.
1552                  */
1553                 spin_unlock_irqrestore(&ide_lock, flags);
1554                 return IRQ_NONE;
1555         }
1556         if (!hwgroup->busy) {
1557                 hwgroup->busy = 1;      /* paranoia */
1558                 printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name);
1559         }
1560         hwgroup->handler = NULL;
1561         del_timer(&hwgroup->timer);
1562         spin_unlock(&ide_lock);
1563
1564         if (drive->unmask)
1565                 local_irq_enable();
1566         /* service this interrupt, may set handler for next interrupt */
1567         startstop = handler(drive);
1568         spin_lock_irq(&ide_lock);
1569
1570         /*
1571          * Note that handler() may have set things up for another
1572          * interrupt to occur soon, but it cannot happen until
1573          * we exit from this routine, because it will be the
1574          * same irq as is currently being serviced here, and Linux
1575          * won't allow another of the same (on any CPU) until we return.
1576          */
1577         drive->service_time = jiffies - drive->service_start;
1578         if (startstop == ide_stopped) {
1579                 if (hwgroup->handler == NULL) { /* paranoia */
1580                         hwgroup->busy = 0;
1581                         ide_do_request(hwgroup, hwif->irq);
1582                 } else {
1583                         printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler "
1584                                 "on exit\n", drive->name);
1585                 }
1586         }
1587         spin_unlock_irqrestore(&ide_lock, flags);
1588         return IRQ_HANDLED;
1589 }
1590
1591 /**
1592  *      ide_init_drive_cmd      -       initialize a drive command request
1593  *      @rq: request object
1594  *
1595  *      Initialize a request before we fill it in and send it down to
1596  *      ide_do_drive_cmd. Commands must be set up by this function. Right
1597  *      now it doesn't do a lot, but if that changes abusers will have a
1598  *      nasty suprise.
1599  */
1600
1601 void ide_init_drive_cmd (struct request *rq)
1602 {
1603         memset(rq, 0, sizeof(*rq));
1604         rq->flags = REQ_DRIVE_CMD;
1605         rq->ref_count = 1;
1606 }
1607
1608 EXPORT_SYMBOL(ide_init_drive_cmd);
1609
1610 /**
1611  *      ide_do_drive_cmd        -       issue IDE special command
1612  *      @drive: device to issue command
1613  *      @rq: request to issue
1614  *      @action: action for processing
1615  *
1616  *      This function issues a special IDE device request
1617  *      onto the request queue.
1618  *
1619  *      If action is ide_wait, then the rq is queued at the end of the
1620  *      request queue, and the function sleeps until it has been processed.
1621  *      This is for use when invoked from an ioctl handler.
1622  *
1623  *      If action is ide_preempt, then the rq is queued at the head of
1624  *      the request queue, displacing the currently-being-processed
1625  *      request and this function returns immediately without waiting
1626  *      for the new rq to be completed.  This is VERY DANGEROUS, and is
1627  *      intended for careful use by the ATAPI tape/cdrom driver code.
1628  *
1629  *      If action is ide_end, then the rq is queued at the end of the
1630  *      request queue, and the function returns immediately without waiting
1631  *      for the new rq to be completed. This is again intended for careful
1632  *      use by the ATAPI tape/cdrom driver code.
1633  */
1634
1635 int ide_do_drive_cmd (ide_drive_t *drive, struct request *rq, ide_action_t action)
1636 {
1637         unsigned long flags;
1638         ide_hwgroup_t *hwgroup = HWGROUP(drive);
1639         DECLARE_COMPLETION(wait);
1640         int where = ELEVATOR_INSERT_BACK, err;
1641         int must_wait = (action == ide_wait || action == ide_head_wait);
1642
1643         rq->errors = 0;
1644         rq->rq_status = RQ_ACTIVE;
1645
1646         /*
1647          * we need to hold an extra reference to request for safe inspection
1648          * after completion
1649          */
1650         if (must_wait) {
1651                 rq->ref_count++;
1652                 rq->waiting = &wait;
1653                 rq->end_io = blk_end_sync_rq;
1654         }
1655
1656         spin_lock_irqsave(&ide_lock, flags);
1657         if (action == ide_preempt)
1658                 hwgroup->rq = NULL;
1659         if (action == ide_preempt || action == ide_head_wait) {
1660                 where = ELEVATOR_INSERT_FRONT;
1661                 rq->flags |= REQ_PREEMPT;
1662         }
1663         __elv_add_request(drive->queue, rq, where, 0);
1664         ide_do_request(hwgroup, IDE_NO_IRQ);
1665         spin_unlock_irqrestore(&ide_lock, flags);
1666
1667         err = 0;
1668         if (must_wait) {
1669                 wait_for_completion(&wait);
1670                 rq->waiting = NULL;
1671                 if (rq->errors)
1672                         err = -EIO;
1673
1674                 blk_put_request(rq);
1675         }
1676
1677         return err;
1678 }
1679
1680 EXPORT_SYMBOL(ide_do_drive_cmd);