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
  51 #include <asm/byteorder.h>
  52 #include <asm/irq.h>
  53 #include <asm/uaccess.h>
  54 #include <asm/io.h>
  55 #include <asm/bitops.h>
  56
  57 /**
  58  *      ide_end_request         -       complete an IDE I/O
  59  *      @drive: IDE device for the I/O
  60  *      @uptodate:
  61  *      @nr_sectors: number of sectors completed
  62  *
  63  *      This is our end_request wrapper function. We complete the I/O
  64  *      update random number input and dequeue the request, which if
  65  *      it was tagged may be out of order.
  66  */
  67
  68 int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
  69 {
  70         struct request *rq;
  71         unsigned long flags;
  72         int ret = 1;
  73
  74         spin_lock_irqsave(&ide_lock, flags);
  75         rq = HWGROUP(drive)->rq;
  76
  77         BUG_ON(!(rq->flags & REQ_STARTED));
  78
  79         if (!nr_sectors)
  80                 nr_sectors = rq->hard_cur_sectors;
  81
  82         /*
  83          * if failfast is set on a request, override number of sectors and
  84          * complete the whole request right now
  85          */
  86         if (blk_noretry_request(rq) && !uptodate)
  87                 nr_sectors = rq->hard_nr_sectors;
  88
  89         /*
  90          * decide whether to reenable DMA -- 3 is a random magic for now,
  91          * if we DMA timeout more than 3 times, just stay in PIO
  92          */
  93         if (drive->state == DMA_PIO_RETRY && drive->retry_pio <= 3) {
  94                 drive->state = 0;
  95                 HWGROUP(drive)->hwif->ide_dma_on(drive);
  96         }
  97
  98         if (!end_that_request_first(rq, uptodate, nr_sectors)) {
  99                 add_disk_randomness(rq->rq_disk);
 100                 blkdev_dequeue_request(rq);
 101                 HWGROUP(drive)->rq = NULL;
 102                 end_that_request_last(rq);
 103                 ret = 0;
 104         }
 105         spin_unlock_irqrestore(&ide_lock, flags);
 106         return ret;
 107 }
 108
 109 EXPORT_SYMBOL(ide_end_request);
 110
 111 /**
 112  *      ide_complete_pm_request - end the current Power Management request
 113  *      @drive: target drive
 114  *      @rq: request
 115  *
 116  *      This function cleans up the current PM request and stops the queue
 117  *      if necessary.
 118  */
 119 static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
 120 {
 121         unsigned long flags;
 122
 123 #ifdef DEBUG_PM
 124         printk("%s: completing PM request, %s\n", drive->name,
 125                blk_pm_suspend_request(rq) ? "suspend" : "resume");
 126 #endif
 127         spin_lock_irqsave(&ide_lock, flags);
 128         if (blk_pm_suspend_request(rq)) {
 129                 blk_stop_queue(drive->queue);
 130         } else {
 131                 drive->blocked = 0;
 132                 blk_start_queue(drive->queue);
 133         }
 134         blkdev_dequeue_request(rq);
 135         HWGROUP(drive)->rq = NULL;
 136         end_that_request_last(rq);
 137         spin_unlock_irqrestore(&ide_lock, flags);
 138 }
 139
 140 /**
 141  *      ide_end_drive_cmd       -       end an explicit drive command
 142  *      @drive: command
 143  *      @stat: status bits
 144  *      @err: error bits
 145  *
 146  *      Clean up after success/failure of an explicit drive command.
 147  *      These get thrown onto the queue so they are synchronized with
 148  *      real I/O operations on the drive.
 149  *
 150  *      In LBA48 mode we have to read the register set twice to get
 151  *      all the extra information out.
 152  */
 153
 154 void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err)
 155 {
 156         ide_hwif_t *hwif = HWIF(drive);
 157         unsigned long flags;
 158         struct request *rq;
 159
 160         spin_lock_irqsave(&ide_lock, flags);
 161         rq = HWGROUP(drive)->rq;
 162         spin_unlock_irqrestore(&ide_lock, flags);
 163
 164         if (rq->flags & REQ_DRIVE_CMD) {
 165                 u8 *args = (u8 *) rq->buffer;
 166                 if (rq->errors == 0)
 167                         rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
 168
 169                 if (args) {
 170                         args[0] = stat;
 171                         args[1] = err;
 172                         args[2] = hwif->INB(IDE_NSECTOR_REG);
 173                 }
 174         } else if (rq->flags & REQ_DRIVE_TASK) {
 175                 u8 *args = (u8 *) rq->buffer;
 176                 if (rq->errors == 0)
 177                         rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
 178
 179                 if (args) {
 180                         args[0] = stat;
 181                         args[1] = err;
 182                         args[2] = hwif->INB(IDE_NSECTOR_REG);
 183                         args[3] = hwif->INB(IDE_SECTOR_REG);
 184                         args[4] = hwif->INB(IDE_LCYL_REG);
 185                         args[5] = hwif->INB(IDE_HCYL_REG);
 186                         args[6] = hwif->INB(IDE_SELECT_REG);
 187                 }
 188         } else if (rq->flags & REQ_DRIVE_TASKFILE) {
 189                 ide_task_t *args = (ide_task_t *) rq->special;
 190                 if (rq->errors == 0)
 191                         rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
 192
 193                 if (args) {
 194                         if (args->tf_in_flags.b.data) {
 195                                 u16 data                                = hwif->INW(IDE_DATA_REG);
 196                                 args->tfRegister[IDE_DATA_OFFSET]       = (data) & 0xFF;
 197                                 args->hobRegister[IDE_DATA_OFFSET]      = (data >> 8) & 0xFF;
 198                         }
 199                         args->tfRegister[IDE_ERROR_OFFSET]   = err;
 200                         args->tfRegister[IDE_NSECTOR_OFFSET] = hwif->INB(IDE_NSECTOR_REG);
 201                         args->tfRegister[IDE_SECTOR_OFFSET]  = hwif->INB(IDE_SECTOR_REG);
 202                         args->tfRegister[IDE_LCYL_OFFSET]    = hwif->INB(IDE_LCYL_REG);
 203                         args->tfRegister[IDE_HCYL_OFFSET]    = hwif->INB(IDE_HCYL_REG);
 204                         args->tfRegister[IDE_SELECT_OFFSET]  = hwif->INB(IDE_SELECT_REG);
 205                         args->tfRegister[IDE_STATUS_OFFSET]  = stat;
 206
 207                         if (drive->addressing == 1) {
 208                                 hwif->OUTB(drive->ctl|0x80, IDE_CONTROL_REG);
 209                                 args->hobRegister[IDE_FEATURE_OFFSET]   = hwif->INB(IDE_FEATURE_REG);
 210                                 args->hobRegister[IDE_NSECTOR_OFFSET]   = hwif->INB(IDE_NSECTOR_REG);
 211                                 args->hobRegister[IDE_SECTOR_OFFSET]    = hwif->INB(IDE_SECTOR_REG);
 212                                 args->hobRegister[IDE_LCYL_OFFSET]      = hwif->INB(IDE_LCYL_REG);
 213                                 args->hobRegister[IDE_HCYL_OFFSET]      = hwif->INB(IDE_HCYL_REG);
 214                         }
 215                 }
 216         } else if (blk_pm_request(rq)) {
 217 #ifdef DEBUG_PM
 218                 printk("%s: complete_power_step(step: %d, stat: %x, err: %x)\n",
 219                         drive->name, rq->pm->pm_step, stat, err);
 220 #endif
 221                 DRIVER(drive)->complete_power_step(drive, rq, stat, err);
 222                 if (rq->pm->pm_step == ide_pm_state_completed)
 223                         ide_complete_pm_request(drive, rq);
 224                 return;
 225         }
 226
 227         spin_lock_irqsave(&ide_lock, flags);
 228         blkdev_dequeue_request(rq);
 229         HWGROUP(drive)->rq = NULL;
 230         end_that_request_last(rq);
 231         spin_unlock_irqrestore(&ide_lock, flags);
 232 }
 233
 234 EXPORT_SYMBOL(ide_end_drive_cmd);
 235
 236 /**
 237  *      try_to_flush_leftover_data      -       flush junk
 238  *      @drive: drive to flush
 239  *
 240  *      try_to_flush_leftover_data() is invoked in response to a drive
 241  *      unexpectedly having its DRQ_STAT bit set.  As an alternative to
 242  *      resetting the drive, this routine tries to clear the condition
 243  *      by read a sector's worth of data from the drive.  Of course,
 244  *      this may not help if the drive is *waiting* for data from *us*.
 245  */
 246 void try_to_flush_leftover_data (ide_drive_t *drive)
 247 {
 248         int i = (drive->mult_count ? drive->mult_count : 1) * SECTOR_WORDS;
 249
 250         if (drive->media != ide_disk)
 251                 return;
 252         while (i > 0) {
 253                 u32 buffer[16];
 254                 u32 wcount = (i > 16) ? 16 : i;
 255
 256                 i -= wcount;
 257                 HWIF(drive)->ata_input_data(drive, buffer, wcount);
 258         }
 259 }
 260
 261 EXPORT_SYMBOL(try_to_flush_leftover_data);
 262
 263 /*
 264  * FIXME Add an ATAPI error
 265  */
 266
 267 /**
 268  *      ide_error       -       handle an error on the IDE
 269  *      @drive: drive the error occurred on
 270  *      @msg: message to report
 271  *      @stat: status bits
 272  *
 273  *      ide_error() takes action based on the error returned by the drive.
 274  *      For normal I/O that may well include retries. We deal with
 275  *      both new-style (taskfile) and old style command handling here.
 276  *      In the case of taskfile command handling there is work left to
 277  *      do
 278  */
 279
 280 ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat)
 281 {
 282         ide_hwif_t *hwif;
 283         struct request *rq;
 284         u8 err;
 285
 286         err = ide_dump_status(drive, msg, stat);
 287         if (drive == NULL || (rq = HWGROUP(drive)->rq) == NULL)
 288                 return ide_stopped;
 289
 290         hwif = HWIF(drive);
 291         /* retry only "normal" I/O: */
 292         if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK)) {
 293                 rq->errors = 1;
 294                 ide_end_drive_cmd(drive, stat, err);
 295                 return ide_stopped;
 296         }
 297         if (rq->flags & REQ_DRIVE_TASKFILE) {
 298                 rq->errors = 1;
 299                 ide_end_drive_cmd(drive, stat, err);
 300                 return ide_stopped;
 301         }
 302
 303         if (stat & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) {
 304                  /* other bits are useless when BUSY */
 305                 rq->errors |= ERROR_RESET;
 306         } else {
 307                 if (drive->media != ide_disk)
 308                         goto media_out;
 309
 310                 if (stat & ERR_STAT) {
 311                         /* err has different meaning on cdrom and tape */
 312                         if (err == ABRT_ERR) {
 313                                 if (drive->select.b.lba &&
 314                                     (hwif->INB(IDE_COMMAND_REG) == WIN_SPECIFY))
 315                                         /* some newer drives don't
 316                                          * support WIN_SPECIFY
 317                                          */
 318                                         return ide_stopped;
 319                         } else if ((err & BAD_CRC) == BAD_CRC) {
 320                                 drive->crc_count++;
 321                                 /* UDMA crc error -- just retry the operation */
 322                         } else if (err & (BBD_ERR | ECC_ERR)) {
 323                                 /* retries won't help these */
 324                                 rq->errors = ERROR_MAX;
 325                         } else if (err & TRK0_ERR) {
 326                                 /* help it find track zero */
 327                                 rq->errors |= ERROR_RECAL;
 328                         }
 329                 }
 330 media_out:
 331                 if ((stat & DRQ_STAT) && rq_data_dir(rq) != WRITE)
 332                         try_to_flush_leftover_data(drive);
 333         }
 334         if (hwif->INB(IDE_STATUS_REG) & (BUSY_STAT|DRQ_STAT)) {
 335                 /* force an abort */
 336                 hwif->OUTB(WIN_IDLEIMMEDIATE,IDE_COMMAND_REG);
 337         }
 338         if (rq->errors >= ERROR_MAX) {
 339                 DRIVER(drive)->end_request(drive, 0, 0);
 340         } else {
 341                 if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
 342                         ++rq->errors;
 343                         return ide_do_reset(drive);
 344                 }
 345                 if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
 346                         drive->special.b.recalibrate = 1;
 347                 ++rq->errors;
 348         }
 349         return ide_stopped;
 350 }
 351
 352 EXPORT_SYMBOL(ide_error);
 353
 354 /**
 355  *      ide_abort       -       abort pending IDE operatins
 356  *      @drive: drive the error occurred on
 357  *      @msg: message to report
 358  *
 359  *      ide_abort kills and cleans up when we are about to do a
 360  *      host initiated reset on active commands. Longer term we
 361  *      want handlers to have sensible abort handling themselves
 362  *
 363  *      This differs fundamentally from ide_error because in
 364  *      this case the command is doing just fine when we
 365  *      blow it away.
 366  */
 367
 368 ide_startstop_t ide_abort(ide_drive_t *drive, const char *msg)
 369 {
 370         ide_hwif_t *hwif;
 371         struct request *rq;
 372
 373         if (drive == NULL || (rq = HWGROUP(drive)->rq) == NULL)
 374                 return ide_stopped;
 375
 376         hwif = HWIF(drive);
 377         /* retry only "normal" I/O: */
 378         if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK)) {
 379                 rq->errors = 1;
 380                 ide_end_drive_cmd(drive, BUSY_STAT, 0);
 381                 return ide_stopped;
 382         }
 383         if (rq->flags & REQ_DRIVE_TASKFILE) {
 384                 rq->errors = 1;
 385                 ide_end_drive_cmd(drive, BUSY_STAT, 0);
 386                 return ide_stopped;
 387         }
 388
 389         rq->errors |= ERROR_RESET;
 390         DRIVER(drive)->end_request(drive, 0, 0);
 391         return ide_stopped;
 392 }
 393
 394 EXPORT_SYMBOL(ide_abort);
 395
 396 /**
 397  *      ide_cmd         -       issue a simple drive command
 398  *      @drive: drive the command is for
 399  *      @cmd: command byte
 400  *      @nsect: sector byte
 401  *      @handler: handler for the command completion
 402  *
 403  *      Issue a simple drive command with interrupts.
 404  *      The drive must be selected beforehand.
 405  */
 406
 407 void ide_cmd (ide_drive_t *drive, u8 cmd, u8 nsect, ide_handler_t *handler)
 408 {
 409         ide_hwif_t *hwif = HWIF(drive);
 410         if (IDE_CONTROL_REG)
 411                 hwif->OUTB(drive->ctl,IDE_CONTROL_REG); /* clear nIEN */
 412         SELECT_MASK(drive,0);
 413         hwif->OUTB(nsect,IDE_NSECTOR_REG);
 414         ide_execute_command(drive, cmd, handler, WAIT_CMD, NULL);
 415 }
 416
 417 EXPORT_SYMBOL(ide_cmd);
 418
 419 /**
 420  *      drive_cmd_intr          -       drive command completion interrupt
 421  *      @drive: drive the completion interrupt occurred on
 422  *
 423  *      drive_cmd_intr() is invoked on completion of a special DRIVE_CMD.
 424  *      We do any necessary daya reading and then wait for the drive to
 425  *      go non busy. At that point we may read the error data and complete
 426  *      the request
 427  */
 428
 429 ide_startstop_t drive_cmd_intr (ide_drive_t *drive)
 430 {
 431         struct request *rq = HWGROUP(drive)->rq;
 432         ide_hwif_t *hwif = HWIF(drive);
 433         u8 *args = (u8 *) rq->buffer;
 434         u8 stat = hwif->INB(IDE_STATUS_REG);
 435         int retries = 10;
 436
 437         local_irq_enable();
 438         if ((stat & DRQ_STAT) && args && args[3]) {
 439                 u8 io_32bit = drive->io_32bit;
 440                 drive->io_32bit = 0;
 441                 hwif->ata_input_data(drive, &args[4], args[3] * SECTOR_WORDS);
 442                 drive->io_32bit = io_32bit;
 443                 while (((stat = hwif->INB(IDE_STATUS_REG)) & BUSY_STAT) && retries--)
 444                         udelay(100);
 445         }
 446
 447         if (!OK_STAT(stat, READY_STAT, BAD_STAT) && DRIVER(drive) != NULL)
 448                 return DRIVER(drive)->error(drive, "drive_cmd", stat);
 449                 /* calls ide_end_drive_cmd */
 450         ide_end_drive_cmd(drive, stat, hwif->INB(IDE_ERROR_REG));
 451         return ide_stopped;
 452 }
 453
 454 EXPORT_SYMBOL(drive_cmd_intr);
 455
 456 /**
 457  *      do_special              -       issue some special commands
 458  *      @drive: drive the command is for
 459  *
 460  *      do_special() is used to issue WIN_SPECIFY, WIN_RESTORE, and WIN_SETMULT
 461  *      commands to a drive.  It used to do much more, but has been scaled
 462  *      back.
 463  */
 464
 465 ide_startstop_t do_special (ide_drive_t *drive)
 466 {
 467         special_t *s = &drive->special;
 468
 469 #ifdef DEBUG
 470         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
 471 #endif
 472         if (s->b.set_tune) {
 473                 s->b.set_tune = 0;
 474                 if (HWIF(drive)->tuneproc != NULL)
 475                         HWIF(drive)->tuneproc(drive, drive->tune_req);
 476                 return ide_stopped;
 477         }
 478         else
 479                 return DRIVER(drive)->special(drive);
 480 }
 481
 482 EXPORT_SYMBOL(do_special);
 483
 484 /**
 485  *      execute_drive_command   -       issue special drive command
 486  *      @drive: the drive to issue th command on
 487  *      @rq: the request structure holding the command
 488  *
 489  *      execute_drive_cmd() issues a special drive command,  usually
 490  *      initiated by ioctl() from the external hdparm program. The
 491  *      command can be a drive command, drive task or taskfile
 492  *      operation. Weirdly you can call it with NULL to wait for
 493  *      all commands to finish. Don't do this as that is due to change
 494  */
 495
 496 ide_startstop_t execute_drive_cmd (ide_drive_t *drive, struct request *rq)
 497 {
 498         ide_hwif_t *hwif = HWIF(drive);
 499         if (rq->flags & REQ_DRIVE_TASKFILE) {
 500                 ide_task_t *args = rq->special;
 501
 502                 if (!args)
 503                         goto done;
 504
 505                 if (args->tf_out_flags.all != 0)
 506                         return flagged_taskfile(drive, args);
 507                 return do_rw_taskfile(drive, args);
 508         } else if (rq->flags & REQ_DRIVE_TASK) {
 509                 u8 *args = rq->buffer;
 510                 u8 sel;
 511
 512                 if (!args)
 513                         goto done;
 514 #ifdef DEBUG
 515                 printk("%s: DRIVE_TASK_CMD ", drive->name);
 516                 printk("cmd=0x%02x ", args[0]);
 517                 printk("fr=0x%02x ", args[1]);
 518                 printk("ns=0x%02x ", args[2]);
 519                 printk("sc=0x%02x ", args[3]);
 520                 printk("lcyl=0x%02x ", args[4]);
 521                 printk("hcyl=0x%02x ", args[5]);
 522                 printk("sel=0x%02x\n", args[6]);
 523 #endif
 524                 hwif->OUTB(args[1], IDE_FEATURE_REG);
 525                 hwif->OUTB(args[3], IDE_SECTOR_REG);
 526                 hwif->OUTB(args[4], IDE_LCYL_REG);
 527                 hwif->OUTB(args[5], IDE_HCYL_REG);
 528                 sel = (args[6] & ~0x10);
 529                 if (drive->select.b.unit)
 530                         sel |= 0x10;
 531                 hwif->OUTB(sel, IDE_SELECT_REG);
 532                 ide_cmd(drive, args[0], args[2], &drive_cmd_intr);
 533                 return ide_started;
 534         } else if (rq->flags & REQ_DRIVE_CMD) {
 535                 u8 *args = rq->buffer;
 536
 537                 if (!args)
 538                         goto done;
 539 #ifdef DEBUG
 540                 printk("%s: DRIVE_CMD ", drive->name);
 541                 printk("cmd=0x%02x ", args[0]);
 542                 printk("sc=0x%02x ", args[1]);
 543                 printk("fr=0x%02x ", args[2]);
 544                 printk("xx=0x%02x\n", args[3]);
 545 #endif
 546                 if (args[0] == WIN_SMART) {
 547                         hwif->OUTB(0x4f, IDE_LCYL_REG);
 548                         hwif->OUTB(0xc2, IDE_HCYL_REG);
 549                         hwif->OUTB(args[2],IDE_FEATURE_REG);
 550                         hwif->OUTB(args[1],IDE_SECTOR_REG);
 551                         ide_cmd(drive, args[0], args[3], &drive_cmd_intr);
 552                         return ide_started;
 553                 }
 554                 hwif->OUTB(args[2],IDE_FEATURE_REG);
 555                 ide_cmd(drive, args[0], args[1], &drive_cmd_intr);
 556                 return ide_started;
 557         }
 558
 559 done:
 560         /*
 561          * NULL is actually a valid way of waiting for
 562          * all current requests to be flushed from the queue.
 563          */
 564 #ifdef DEBUG
 565         printk("%s: DRIVE_CMD (null)\n", drive->name);
 566 #endif
 567         ide_end_drive_cmd(drive,
 568                         hwif->INB(IDE_STATUS_REG),
 569                         hwif->INB(IDE_ERROR_REG));
 570         return ide_stopped;
 571 }
 572
 573 EXPORT_SYMBOL(execute_drive_cmd);
 574
 575 /**
 576  *      start_request   -       start of I/O and command issuing for IDE
 577  *
 578  *      start_request() initiates handling of a new I/O request. It
 579  *      accepts commands and I/O (read/write) requests. It also does
 580  *      the final remapping for weird stuff like EZDrive. Once
 581  *      device mapper can work sector level the EZDrive stuff can go away
 582  *
 583  *      FIXME: this function needs a rename
 584  */
 585
 586 ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 587 {
 588         ide_startstop_t startstop;
 589         sector_t block;
 590
 591         BUG_ON(!(rq->flags & REQ_STARTED));
 592
 593 #ifdef DEBUG
 594         printk("%s: start_request: current=0x%08lx\n",
 595                 HWIF(drive)->name, (unsigned long) rq);
 596 #endif
 597
 598         /* bail early if we've exceeded max_failures */
 599         if (drive->max_failures && (drive->failures > drive->max_failures)) {
 600                 goto kill_rq;
 601         }
 602
 603         /*
 604          * bail early if we've sent a device to sleep, however how to wake
 605          * this needs to be a masked flag.  FIXME for proper operations.
 606          */
 607         if (drive->suspend_reset)
 608                 goto kill_rq;
 609
 610         block    = rq->sector;
 611         if (blk_fs_request(rq) &&
 612             (drive->media == ide_disk || drive->media == ide_floppy)) {
 613                 block += drive->sect0;
 614         }
 615         /* Yecch - this will shift the entire interval,
 616            possibly killing some innocent following sector */
 617         if (block == 0 && drive->remap_0_to_1 == 1)
 618                 block = 1;  /* redirect MBR access to EZ-Drive partn table */
 619
 620         if (blk_pm_suspend_request(rq) &&
 621             rq->pm->pm_step == ide_pm_state_start_suspend)
 622                 /* Mark drive blocked when starting the suspend sequence. */
 623                 drive->blocked = 1;
 624         else if (blk_pm_resume_request(rq) &&
 625                  rq->pm->pm_step == ide_pm_state_start_resume) {
 626                 /*
 627                  * The first thing we do on wakeup is to wait for BSY bit to
 628                  * go away (with a looong timeout) as a drive on this hwif may
 629                  * just be POSTing itself.
 630                  * We do that before even selecting as the "other" device on
 631                  * the bus may be broken enough to walk on our toes at this
 632                  * point.
 633                  */
 634                 int rc;
 635 #ifdef DEBUG_PM
 636                 printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
 637 #endif
 638                 rc = ide_wait_not_busy(HWIF(drive), 35000);
 639                 if (rc)
 640                         printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
 641                 SELECT_DRIVE(drive);
 642                 HWIF(drive)->OUTB(8, HWIF(drive)->io_ports[IDE_CONTROL_OFFSET]);
 643                 rc = ide_wait_not_busy(HWIF(drive), 10000);
 644                 if (rc)
 645                         printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
 646         }
 647
 648         SELECT_DRIVE(drive);
 649         if (ide_wait_stat(&startstop, drive, drive->ready_stat, BUSY_STAT|DRQ_STAT, WAIT_READY)) {
 650                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 651                 return startstop;
 652         }
 653         if (!drive->special.all) {
 654                 if (rq->flags & (REQ_DRIVE_CMD | REQ_DRIVE_TASK))
 655                         return execute_drive_cmd(drive, rq);
 656                 else if (rq->flags & REQ_DRIVE_TASKFILE)
 657                         return execute_drive_cmd(drive, rq);
 658                 else if (blk_pm_request(rq)) {
 659 #ifdef DEBUG_PM
 660                         printk("%s: start_power_step(step: %d)\n",
 661                                 drive->name, rq->pm->pm_step);
 662 #endif
 663                         startstop = DRIVER(drive)->start_power_step(drive, rq);
 664                         if (startstop == ide_stopped &&
 665                             rq->pm->pm_step == ide_pm_state_completed)
 666                                 ide_complete_pm_request(drive, rq);
 667                         return startstop;
 668                 }
 669                 return (DRIVER(drive)->do_request(drive, rq, block));
 670         }
 671         return do_special(drive);
 672 kill_rq:
 673         DRIVER(drive)->end_request(drive, 0, 0);
 674         return ide_stopped;
 675 }
 676
 677 EXPORT_SYMBOL(start_request);
 678
 679 /**
 680  *      ide_stall_queue         -       pause an IDE device
 681  *      @drive: drive to stall
 682  *      @timeout: time to stall for (jiffies)
 683  *
 684  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 685  *      to the hwgroup by sleeping for timeout jiffies.
 686  */
 687
 688 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 689 {
 690         if (timeout > WAIT_WORSTCASE)
 691                 timeout = WAIT_WORSTCASE;
 692         drive->sleep = timeout + jiffies;
 693 }
 694
 695 EXPORT_SYMBOL(ide_stall_queue);
 696
 697 #define WAKEUP(drive)   ((drive)->service_start + 2 * (drive)->service_time)
 698
 699 /**
 700  *      choose_drive            -       select a drive to service
 701  *      @hwgroup: hardware group to select on
 702  *
 703  *      choose_drive() selects the next drive which will be serviced.
 704  *      This is necessary because the IDE layer can't issue commands
 705  *      to both drives on the same cable, unlike SCSI.
 706  */
 707
 708 static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
 709 {
 710         ide_drive_t *drive, *best;
 711
 712 repeat:
 713         best = NULL;
 714         drive = hwgroup->drive;
 715         do {
 716                 if ((!drive->sleep || time_after_eq(jiffies, drive->sleep))
 717                     && !elv_queue_empty(drive->queue)) {
 718                         if (!best
 719                          || (drive->sleep && (!best->sleep || 0 < (signed long)(best->sleep - drive->sleep)))
 720                          || (!best->sleep && 0 < (signed long)(WAKEUP(best) - WAKEUP(drive))))
 721                         {
 722                                 if (!blk_queue_plugged(drive->queue))
 723                                         best = drive;
 724                         }
 725                 }
 726         } while ((drive = drive->next) != hwgroup->drive);
 727         if (best && best->nice1 && !best->sleep && best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
 728                 long t = (signed long)(WAKEUP(best) - jiffies);
 729                 if (t >= WAIT_MIN_SLEEP) {
 730                 /*
 731                  * We *may* have some time to spare, but first let's see if
 732                  * someone can potentially benefit from our nice mood today..
 733                  */
 734                         drive = best->next;
 735                         do {
 736                                 if (!drive->sleep
 737                                 /* FIXME: use time_before */
 738                                  && 0 < (signed long)(WAKEUP(drive) - (jiffies - best->service_time))
 739                                  && 0 < (signed long)((jiffies + t) - WAKEUP(drive)))
 740                                 {
 741                                         ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP));
 742                                         goto repeat;
 743                                 }
 744                         } while ((drive = drive->next) != best);
 745                 }
 746         }
 747         return best;
 748 }
 749
 750 /*
 751  * Issue a new request to a drive from hwgroup
 752  * Caller must have already done spin_lock_irqsave(&ide_lock, ..);
 753  *
 754  * A hwgroup is a serialized group of IDE interfaces.  Usually there is
 755  * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640)
 756  * may have both interfaces in a single hwgroup to "serialize" access.
 757  * Or possibly multiple ISA interfaces can share a common IRQ by being grouped
 758  * together into one hwgroup for serialized access.
 759  *
 760  * Note also that several hwgroups can end up sharing a single IRQ,
 761  * possibly along with many other devices.  This is especially common in
 762  * PCI-based systems with off-board IDE controller cards.
 763  *
 764  * The IDE driver uses the single global ide_lock spinlock to protect
 765  * access to the request queues, and to protect the hwgroup->busy flag.
 766  *
 767  * The first thread into the driver for a particular hwgroup sets the
 768  * hwgroup->busy flag to indicate that this hwgroup is now active,
 769  * and then initiates processing of the top request from the request queue.
 770  *
 771  * Other threads attempting entry notice the busy setting, and will simply
 772  * queue their new requests and exit immediately.  Note that hwgroup->busy
 773  * remains set even when the driver is merely awaiting the next interrupt.
 774  * Thus, the meaning is "this hwgroup is busy processing a request".
 775  *
 776  * When processing of a request completes, the completing thread or IRQ-handler
 777  * will start the next request from the queue.  If no more work remains,
 778  * the driver will clear the hwgroup->busy flag and exit.
 779  *
 780  * The ide_lock (spinlock) is used to protect all access to the
 781  * hwgroup->busy flag, but is otherwise not needed for most processing in
 782  * the driver.  This makes the driver much more friendlier to shared IRQs
 783  * than previous designs, while remaining 100% (?) SMP safe and capable.
 784  */
 785 /* --BenH: made non-static as ide-pmac.c uses it to kick the hwgroup back
 786  *         into life on wakeup from machine sleep.
 787  */
 788 void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
 789 {
 790         ide_drive_t     *drive;
 791         ide_hwif_t      *hwif;
 792         struct request  *rq;
 793         ide_startstop_t startstop;
 794
 795         /* for atari only: POSSIBLY BROKEN HERE(?) */
 796         ide_get_lock(ide_intr, hwgroup);
 797
 798         /* caller must own ide_lock */
 799         BUG_ON(!irqs_disabled());
 800
 801         while (!hwgroup->busy) {
 802                 hwgroup->busy = 1;
 803                 drive = choose_drive(hwgroup);
 804                 if (drive == NULL) {
 805                         unsigned long sleep = 0;
 806                         hwgroup->rq = NULL;
 807                         drive = hwgroup->drive;
 808                         do {
 809                                 if (drive->sleep && (!sleep || 0 < (signed long)(sleep - drive->sleep)))
 810                                         sleep = drive->sleep;
 811                         } while ((drive = drive->next) != hwgroup->drive);
 812                         if (sleep) {
 813                 /*
 814                  * Take a short snooze, and then wake up this hwgroup again.
 815                  * This gives other hwgroups on the same a chance to
 816                  * play fairly with us, just in case there are big differences
 817                  * in relative throughputs.. don't want to hog the cpu too much.
 818                  */
 819                                 if (time_before(sleep, jiffies + WAIT_MIN_SLEEP))
 820                                         sleep = jiffies + WAIT_MIN_SLEEP;
 821 #if 1
 822                                 if (timer_pending(&hwgroup->timer))
 823                                         printk(KERN_CRIT "ide_set_handler: timer already active\n");
 824 #endif
 825                                 /* so that ide_timer_expiry knows what to do */
 826                                 hwgroup->sleeping = 1;
 827                                 mod_timer(&hwgroup->timer, sleep);
 828                                 /* we purposely leave hwgroup->busy==1
 829                                  * while sleeping */
 830                         } else {
 831                                 /* Ugly, but how can we sleep for the lock
 832                                  * otherwise? perhaps from tq_disk?
 833                                  */
 834
 835                                 /* for atari only */
 836                                 ide_release_lock();
 837                                 hwgroup->busy = 0;
 838                         }
 839
 840                         /* no more work for this hwgroup (for now) */
 841                         return;
 842                 }
 843                 hwif = HWIF(drive);
 844                 if (hwgroup->hwif->sharing_irq &&
 845                     hwif != hwgroup->hwif &&
 846                     hwif->io_ports[IDE_CONTROL_OFFSET]) {
 847                         /* set nIEN for previous hwif */
 848                         SELECT_INTERRUPT(drive);
 849                 }
 850                 hwgroup->hwif = hwif;
 851                 hwgroup->drive = drive;
 852                 drive->sleep = 0;
 853                 drive->service_start = jiffies;
 854
 855                 if (blk_queue_plugged(drive->queue)) {
 856                         printk(KERN_ERR "ide: huh? queue was plugged!\n");
 857                         break;
 858                 }
 859
 860                 /*
 861                  * we know that the queue isn't empty, but this can happen
 862                  * if the q->prep_rq_fn() decides to kill a request
 863                  */
 864                 rq = elv_next_request(drive->queue);
 865                 if (!rq) {
 866                         hwgroup->busy = 0;
 867                         break;
 868                 }
 869
 870                 /*
 871                  * Sanity: don't accept a request that isn't a PM request
 872                  * if we are currently power managed. This is very important as
 873                  * blk_stop_queue() doesn't prevent the elv_next_request()
 874                  * above to return us whatever is in the queue. Since we call
 875                  * ide_do_request() ourselves, we end up taking requests while
 876                  * the queue is blocked...
 877                  *
 878                  * We let requests forced at head of queue with ide-preempt
 879                  * though. I hope that doesn't happen too much, hopefully not
 880                  * unless the subdriver triggers such a thing in its own PM
 881                  * state machine.
 882                  */
 883                 if (drive->blocked && !blk_pm_request(rq) && !(rq->flags & REQ_PREEMPT)) {
 884                         /* We clear busy, there should be no pending ATA command at this point. */
 885                         hwgroup->busy = 0;
 886                         break;
 887                 }
 888
 889                 hwgroup->rq = rq;
 890
 891                 /*
 892                  * Some systems have trouble with IDE IRQs arriving while
 893                  * the driver is still setting things up.  So, here we disable
 894                  * the IRQ used by this interface while the request is being started.
 895                  * This may look bad at first, but pretty much the same thing
 896                  * happens anyway when any interrupt comes in, IDE or otherwise
 897                  *  -- the kernel masks the IRQ while it is being handled.
 898                  */
 899                 if (hwif->irq != masked_irq)
 900                         disable_irq_nosync(hwif->irq);
 901                 spin_unlock(&ide_lock);
 902                 local_irq_enable();
 903                         /* allow other IRQs while we start this request */
 904                 startstop = start_request(drive, rq);
 905                 spin_lock_irq(&ide_lock);
 906                 if (hwif->irq != masked_irq)
 907                         enable_irq(hwif->irq);
 908                 if (startstop == ide_stopped)
 909                         hwgroup->busy = 0;
 910         }
 911 }
 912
 913 EXPORT_SYMBOL(ide_do_request);
 914
 915 /*
 916  * Passes the stuff to ide_do_request
 917  */
 918 void do_ide_request(request_queue_t *q)
 919 {
 920         ide_do_request(q->queuedata, IDE_NO_IRQ);
 921 }
 922
 923 /*
 924  * un-busy the hwgroup etc, and clear any pending DMA status. we want to
 925  * retry the current request in pio mode instead of risking tossing it
 926  * all away
 927  */
 928 static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
 929 {
 930         ide_hwif_t *hwif = HWIF(drive);
 931         struct request *rq;
 932         ide_startstop_t ret = ide_stopped;
 933
 934         /*
 935          * end current dma transaction
 936          */
 937
 938         if (error < 0) {
 939                 printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
 940                 (void)HWIF(drive)->ide_dma_end(drive);
 941                 ret = DRIVER(drive)->error(drive, "dma timeout error",
 942                                                 hwif->INB(IDE_STATUS_REG));
 943         } else {
 944                 printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
 945                 (void) hwif->ide_dma_timeout(drive);
 946         }
 947
 948         /*
 949          * disable dma for now, but remember that we did so because of
 950          * a timeout -- we'll reenable after we finish this next request
 951          * (or rather the first chunk of it) in pio.
 952          */
 953         drive->retry_pio++;
 954         drive->state = DMA_PIO_RETRY;
 955         (void) hwif->ide_dma_off_quietly(drive);
 956
 957         /*
 958          * un-busy drive etc (hwgroup->busy is cleared on return) and
 959          * make sure request is sane
 960          */
 961         rq = HWGROUP(drive)->rq;
 962         HWGROUP(drive)->rq = NULL;
 963
 964         rq->errors = 0;
 965         rq->sector = rq->bio->bi_sector;
 966         rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9;
 967         rq->hard_cur_sectors = rq->current_nr_sectors;
 968         if (rq->bio)
 969                 rq->buffer = NULL;
 970
 971         return ret;
 972 }
 973
 974 /**
 975  *      ide_timer_expiry        -       handle lack of an IDE interrupt
 976  *      @data: timer callback magic (hwgroup)
 977  *
 978  *      An IDE command has timed out before the expected drive return
 979  *      occurred. At this point we attempt to clean up the current
 980  *      mess. If the current handler includes an expiry handler then
 981  *      we invoke the expiry handler, and providing it is happy the
 982  *      work is done. If that fails we apply generic recovery rules
 983  *      invoking the handler and checking the drive DMA status. We
 984  *      have an excessively incestuous relationship with the DMA
 985  *      logic that wants cleaning up.
 986  */
 987
 988 void ide_timer_expiry (unsigned long data)
 989 {
 990         ide_hwgroup_t   *hwgroup = (ide_hwgroup_t *) data;
 991         ide_handler_t   *handler;
 992         ide_expiry_t    *expiry;
 993         unsigned long   flags;
 994         unsigned long   wait = -1;
 995
 996         spin_lock_irqsave(&ide_lock, flags);
 997
 998         if ((handler = hwgroup->handler) == NULL) {
 999                 /*
1000                  * Either a marginal timeout occurred
1001                  * (got the interrupt just as timer expired),
1002                  * or we were "sleeping" to give other devices a chance.
1003                  * Either way, we don't really want to complain about anything.
1004                  */
1005                 if (hwgroup->sleeping) {
1006                         hwgroup->sleeping = 0;
1007                         hwgroup->busy = 0;
1008                 }
1009         } else {
1010                 ide_drive_t *drive = hwgroup->drive;
1011                 if (!drive) {
1012                         printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
1013                         hwgroup->handler = NULL;
1014                 } else {
1015                         ide_hwif_t *hwif;
1016                         ide_startstop_t startstop = ide_stopped;
1017                         if (!hwgroup->busy) {
1018                                 hwgroup->busy = 1;      /* paranoia */
1019                                 printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name);
1020                         }
1021                         if ((expiry = hwgroup->expiry) != NULL) {
1022                                 /* continue */
1023                                 if ((wait = expiry(drive)) > 0) {
1024                                         /* reset timer */
1025                                         hwgroup->timer.expires  = jiffies + wait;
1026                                         add_timer(&hwgroup->timer);
1027                                         spin_unlock_irqrestore(&ide_lock, flags);
1028                                         return;
1029                                 }
1030                         }
1031                         hwgroup->handler = NULL;
1032                         /*
1033                          * We need to simulate a real interrupt when invoking
1034                          * the handler() function, which means we need to
1035                          * globally mask the specific IRQ:
1036                          */
1037                         spin_unlock(&ide_lock);
1038                         hwif  = HWIF(drive);
1039 #if DISABLE_IRQ_NOSYNC
1040                         disable_irq_nosync(hwif->irq);
1041 #else
1042                         /* disable_irq_nosync ?? */
1043                         disable_irq(hwif->irq);
1044 #endif /* DISABLE_IRQ_NOSYNC */
1045                         /* local CPU only,
1046                          * as if we were handling an interrupt */
1047                         local_irq_disable();
1048                         if (hwgroup->poll_timeout != 0) {
1049                                 startstop = handler(drive);
1050                         } else if (drive_is_ready(drive)) {
1051                                 if (drive->waiting_for_dma)
1052                                         (void) hwgroup->hwif->ide_dma_lostirq(drive);
1053                                 (void)ide_ack_intr(hwif);
1054                                 printk(KERN_WARNING "%s: lost interrupt\n", drive->name);
1055                                 startstop = handler(drive);
1056                         } else {
1057                                 if (drive->waiting_for_dma) {
1058                                         startstop = ide_dma_timeout_retry(drive, wait);
1059                                 } else
1060                                         startstop =
1061                                         DRIVER(drive)->error(drive, "irq timeout", hwif->INB(IDE_STATUS_REG));
1062                         }
1063                         drive->service_time = jiffies - drive->service_start;
1064                         spin_lock_irq(&ide_lock);
1065                         enable_irq(hwif->irq);
1066                         if (startstop == ide_stopped)
1067                                 hwgroup->busy = 0;
1068                 }
1069         }
1070         ide_do_request(hwgroup, IDE_NO_IRQ);
1071         spin_unlock_irqrestore(&ide_lock, flags);
1072 }
1073
1074 EXPORT_SYMBOL(ide_timer_expiry);
1075
1076 /**
1077  *      unexpected_intr         -       handle an unexpected IDE interrupt
1078  *      @irq: interrupt line
1079  *      @hwgroup: hwgroup being processed
1080  *
1081  *      There's nothing really useful we can do with an unexpected interrupt,
1082  *      other than reading the status register (to clear it), and logging it.
1083  *      There should be no way that an irq can happen before we're ready for it,
1084  *      so we needn't worry much about losing an "important" interrupt here.
1085  *
1086  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
1087  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
1088  *      looks "good", we just ignore the interrupt completely.
1089  *
1090  *      This routine assumes __cli() is in effect when called.
1091  *
1092  *      If an unexpected interrupt happens on irq15 while we are handling irq14
1093  *      and if the two interfaces are "serialized" (CMD640), then it looks like
1094  *      we could screw up by interfering with a new request being set up for
1095  *      irq15.
1096  *
1097  *      In reality, this is a non-issue.  The new command is not sent unless
1098  *      the drive is ready to accept one, in which case we know the drive is
1099  *      not trying to interrupt us.  And ide_set_handler() is always invoked
1100  *      before completing the issuance of any new drive command, so we will not
1101  *      be accidentally invoked as a result of any valid command completion
1102  *      interrupt.
1103  *
1104  *      Note that we must walk the entire hwgroup here. We know which hwif
1105  *      is doing the current command, but we don't know which hwif burped
1106  *      mysteriously.
1107  */
1108
1109 static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
1110 {
1111         u8 stat;
1112         ide_hwif_t *hwif = hwgroup->hwif;
1113
1114         /*
1115          * handle the unexpected interrupt
1116          */
1117         do {
1118                 if (hwif->irq == irq) {
1119                         stat = hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
1120                         if (!OK_STAT(stat, READY_STAT, BAD_STAT)) {
1121                                 /* Try to not flood the console with msgs */
1122                                 static unsigned long last_msgtime, count;
1123                                 ++count;
1124                                 if (time_after(jiffies, last_msgtime + HZ)) {
1125                                         last_msgtime = jiffies;
1126                                         printk(KERN_ERR "%s%s: unexpected interrupt, "
1127                                                 "status=0x%02x, count=%ld\n",
1128                                                 hwif->name,
1129                                                 (hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count);
1130                                 }
1131                         }
1132                 }
1133         } while ((hwif = hwif->next) != hwgroup->hwif);
1134 }
1135
1136 /**
1137  *      ide_intr        -       default IDE interrupt handler
1138  *      @irq: interrupt number
1139  *      @dev_id: hwif group
1140  *      @regs: unused weirdness from the kernel irq layer
1141  *
1142  *      This is the default IRQ handler for the IDE layer. You should
1143  *      not need to override it. If you do be aware it is subtle in
1144  *      places
1145  *
1146  *      hwgroup->hwif is the interface in the group currently performing
1147  *      a command. hwgroup->drive is the drive and hwgroup->handler is
1148  *      the IRQ handler to call. As we issue a command the handlers
1149  *      step through multiple states, reassigning the handler to the
1150  *      next step in the process. Unlike a smart SCSI controller IDE
1151  *      expects the main processor to sequence the various transfer
1152  *      stages. We also manage a poll timer to catch up with most
1153  *      timeout situations. There are still a few where the handlers
1154  *      don't ever decide to give up.
1155  *
1156  *      The handler eventually returns ide_stopped to indicate the
1157  *      request completed. At this point we issue the next request
1158  *      on the hwgroup and the process begins again.
1159  */
1160
1161 irqreturn_t ide_intr (int irq, void *dev_id, struct pt_regs *regs)
1162 {
1163         unsigned long flags;
1164         ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
1165         ide_hwif_t *hwif;
1166         ide_drive_t *drive;
1167         ide_handler_t *handler;
1168         ide_startstop_t startstop;
1169
1170         spin_lock_irqsave(&ide_lock, flags);
1171         hwif = hwgroup->hwif;
1172
1173         if (!ide_ack_intr(hwif)) {
1174                 spin_unlock_irqrestore(&ide_lock, flags);
1175                 return IRQ_NONE;
1176         }
1177
1178         if ((handler = hwgroup->handler) == NULL ||
1179             hwgroup->poll_timeout != 0) {
1180                 /*
1181                  * Not expecting an interrupt from this drive.
1182                  * That means this could be:
1183                  *      (1) an interrupt from another PCI device
1184                  *      sharing the same PCI INT# as us.
1185                  * or   (2) a drive just entered sleep or standby mode,
1186                  *      and is interrupting to let us know.
1187                  * or   (3) a spurious interrupt of unknown origin.
1188                  *
1189                  * For PCI, we cannot tell the difference,
1190                  * so in that case we just ignore it and hope it goes away.
1191                  *
1192                  * FIXME: unexpected_intr should be hwif-> then we can
1193                  * remove all the ifdef PCI crap
1194                  */
1195 #ifdef CONFIG_BLK_DEV_IDEPCI
1196                 if (hwif->pci_dev && !hwif->pci_dev->vendor)
1197 #endif  /* CONFIG_BLK_DEV_IDEPCI */
1198                 {
1199                         /*
1200                          * Probably not a shared PCI interrupt,
1201                          * so we can safely try to do something about it:
1202                          */
1203                         unexpected_intr(irq, hwgroup);
1204 #ifdef CONFIG_BLK_DEV_IDEPCI
1205                 } else {
1206                         /*
1207                          * Whack the status register, just in case
1208                          * we have a leftover pending IRQ.
1209                          */
1210                         (void) hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
1211 #endif /* CONFIG_BLK_DEV_IDEPCI */
1212                 }
1213                 spin_unlock_irqrestore(&ide_lock, flags);
1214                 return IRQ_NONE;
1215         }
1216         drive = hwgroup->drive;
1217         if (!drive) {
1218                 /*
1219                  * This should NEVER happen, and there isn't much
1220                  * we could do about it here.
1221                  *
1222                  * [Note - this can occur if the drive is hot unplugged]
1223                  */
1224                 spin_unlock_irqrestore(&ide_lock, flags);
1225                 return IRQ_HANDLED;
1226         }
1227         if (!drive_is_ready(drive)) {
1228                 /*
1229                  * This happens regularly when we share a PCI IRQ with
1230                  * another device.  Unfortunately, it can also happen
1231                  * with some buggy drives that trigger the IRQ before
1232                  * their status register is up to date.  Hopefully we have
1233                  * enough advance overhead that the latter isn't a problem.
1234                  */
1235                 spin_unlock_irqrestore(&ide_lock, flags);
1236                 return IRQ_NONE;
1237         }
1238         if (!hwgroup->busy) {
1239                 hwgroup->busy = 1;      /* paranoia */
1240                 printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name);
1241         }
1242         hwgroup->handler = NULL;
1243         del_timer(&hwgroup->timer);
1244         spin_unlock(&ide_lock);
1245
1246         if (drive->unmask)
1247                 local_irq_enable();
1248         /* service this interrupt, may set handler for next interrupt */
1249         startstop = handler(drive);
1250         spin_lock_irq(&ide_lock);
1251
1252         /*
1253          * Note that handler() may have set things up for another
1254          * interrupt to occur soon, but it cannot happen until
1255          * we exit from this routine, because it will be the
1256          * same irq as is currently being serviced here, and Linux
1257          * won't allow another of the same (on any CPU) until we return.
1258          */
1259         drive->service_time = jiffies - drive->service_start;
1260         if (startstop == ide_stopped) {
1261                 if (hwgroup->handler == NULL) { /* paranoia */
1262                         hwgroup->busy = 0;
1263                         ide_do_request(hwgroup, hwif->irq);
1264                 } else {
1265                         printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler "
1266                                 "on exit\n", drive->name);
1267                 }
1268         }
1269         spin_unlock_irqrestore(&ide_lock, flags);
1270         return IRQ_HANDLED;
1271 }
1272
1273 EXPORT_SYMBOL(ide_intr);
1274
1275 /**
1276  *      ide_init_drive_cmd      -       initialize a drive command request
1277  *      @rq: request object
1278  *
1279  *      Initialize a request before we fill it in and send it down to
1280  *      ide_do_drive_cmd. Commands must be set up by this function. Right
1281  *      now it doesn't do a lot, but if that changes abusers will have a
1282  *      nasty suprise.
1283  */
1284
1285 void ide_init_drive_cmd (struct request *rq)
1286 {
1287         memset(rq, 0, sizeof(*rq));
1288         rq->flags = REQ_DRIVE_CMD;
1289 }
1290
1291 EXPORT_SYMBOL(ide_init_drive_cmd);
1292
1293 /**
1294  *      ide_do_drive_cmd        -       issue IDE special command
1295  *      @drive: device to issue command
1296  *      @rq: request to issue
1297  *      @action: action for processing
1298  *
1299  *      This function issues a special IDE device request
1300  *      onto the request queue.
1301  *
1302  *      If action is ide_wait, then the rq is queued at the end of the
1303  *      request queue, and the function sleeps until it has been processed.
1304  *      This is for use when invoked from an ioctl handler.
1305  *
1306  *      If action is ide_preempt, then the rq is queued at the head of
1307  *      the request queue, displacing the currently-being-processed
1308  *      request and this function returns immediately without waiting
1309  *      for the new rq to be completed.  This is VERY DANGEROUS, and is
1310  *      intended for careful use by the ATAPI tape/cdrom driver code.
1311  *
1312  *      If action is ide_next, then the rq is queued immediately after
1313  *      the currently-being-processed-request (if any), and the function
1314  *      returns without waiting for the new rq to be completed.  As above,
1315  *      This is VERY DANGEROUS, and is intended for careful use by the
1316  *      ATAPI tape/cdrom driver code.
1317  *
1318  *      If action is ide_end, then the rq is queued at the end of the
1319  *      request queue, and the function returns immediately without waiting
1320  *      for the new rq to be completed. This is again intended for careful
1321  *      use by the ATAPI tape/cdrom driver code.
1322  */
1323
1324 int ide_do_drive_cmd (ide_drive_t *drive, struct request *rq, ide_action_t action)
1325 {
1326         unsigned long flags;
1327         ide_hwgroup_t *hwgroup = HWGROUP(drive);
1328         DECLARE_COMPLETION(wait);
1329         int where = ELEVATOR_INSERT_BACK, err;
1330         int must_wait = (action == ide_wait || action == ide_head_wait);
1331
1332 #ifdef CONFIG_BLK_DEV_PDC4030
1333         /*
1334          *      FIXME: there should be a drive or hwif->special
1335          *      handler that points here by default, not hacks
1336          *      in the ide-io.c code
1337          *
1338          *      FIXME2: That code breaks power management if used with
1339          *      this chipset, that really doesn't belong here !
1340          */
1341         if (HWIF(drive)->chipset == ide_pdc4030 && rq->buffer != NULL)
1342                 return -ENOSYS;  /* special drive cmds not supported */
1343 #endif
1344         rq->errors = 0;
1345         rq->rq_status = RQ_ACTIVE;
1346
1347         rq->rq_disk = drive->disk;
1348
1349         /*
1350          * we need to hold an extra reference to request for safe inspection
1351          * after completion
1352          */
1353         if (must_wait) {
1354                 rq->ref_count++;
1355                 rq->waiting = &wait;
1356         }
1357
1358         spin_lock_irqsave(&ide_lock, flags);
1359         if (action == ide_preempt)
1360                 hwgroup->rq = NULL;
1361         if (action == ide_preempt || action == ide_head_wait) {
1362                 where = ELEVATOR_INSERT_FRONT;
1363                 rq->flags |= REQ_PREEMPT;
1364         }
1365         __elv_add_request(drive->queue, rq, where, 0);
1366         ide_do_request(hwgroup, IDE_NO_IRQ);
1367         spin_unlock_irqrestore(&ide_lock, flags);
1368
1369         err = 0;
1370         if (must_wait) {
1371                 wait_for_completion(&wait);
1372                 rq->waiting = NULL;
1373                 if (rq->errors)
1374                         err = -EIO;
1375
1376                 blk_put_request(rq);
1377         }
1378
1379         return err;
1380 }
1381
1382 EXPORT_SYMBOL(ide_do_drive_cmd);