root/drivers/ide/ide-io.c

DEFINITIONS

1. ide_end_rq
2. ide_complete_cmd
3. ide_complete_rq
4. ide_kill_rq
5. ide_tf_set_specify_cmd
6. ide_tf_set_restore_cmd
7. ide_tf_set_setmult_cmd
8. do_special
9. ide_map_sg
10. ide_init_sg_cmd
11. execute_drive_cmd
12. ide_special_rq
13. start_request
14. ide_stall_queue
15. ide_lock_port
16. ide_unlock_port
17. ide_lock_host
18. ide_unlock_host
19. ide_requeue_and_plug
20. ide_issue_rq
21. ide_queue_rq
22. drive_is_ready
23. ide_timer_expiry
24. unexpected_intr
25. ide_intr
26. ide_pad_transfer
27. ide_insert_request_head

   1 /*
   2  *      IDE I/O functions
   3  *
   4  *      Basic PIO and command management functionality.
   5  *
   6  * This code was split off from ide.c. See ide.c for history and original
   7  * copyrights.
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the
  11  * Free Software Foundation; either version 2, or (at your option) any
  12  * later version.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * For the avoidance of doubt the "preferred form" of this code is one which
  20  * is in an open non patent encumbered format. Where cryptographic key signing
  21  * forms part of the process of creating an executable the information
  22  * including keys needed to generate an equivalently functional executable
  23  * are deemed to be part of the source code.
  24  */
  25  
  26  
  27 #include <linux/module.h>
  28 #include <linux/types.h>
  29 #include <linux/string.h>
  30 #include <linux/kernel.h>
  31 #include <linux/timer.h>
  32 #include <linux/mm.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/major.h>
  35 #include <linux/errno.h>
  36 #include <linux/genhd.h>
  37 #include <linux/blkpg.h>
  38 #include <linux/slab.h>
  39 #include <linux/init.h>
  40 #include <linux/pci.h>
  41 #include <linux/delay.h>
  42 #include <linux/ide.h>
  43 #include <linux/completion.h>
  44 #include <linux/reboot.h>
  45 #include <linux/cdrom.h>
  46 #include <linux/seq_file.h>
  47 #include <linux/device.h>
  48 #include <linux/kmod.h>
  49 #include <linux/scatterlist.h>
  50 #include <linux/bitops.h>
  51 
  52 #include <asm/byteorder.h>
  53 #include <asm/irq.h>
  54 #include <linux/uaccess.h>
  55 #include <asm/io.h>
  56 
  57 int ide_end_rq(ide_drive_t *drive, struct request *rq, blk_status_t error,
  58                unsigned int nr_bytes)
  59 {
  60         /*
  61          * decide whether to reenable DMA -- 3 is a random magic for now,
  62          * if we DMA timeout more than 3 times, just stay in PIO
  63          */
  64         if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
  65             drive->retry_pio <= 3) {
  66                 drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
  67                 ide_dma_on(drive);
  68         }
  69 
  70         if (!blk_update_request(rq, error, nr_bytes)) {
  71                 if (rq == drive->sense_rq) {
  72                         drive->sense_rq = NULL;
  73                         drive->sense_rq_active = false;
  74                 }
  75 
  76                 __blk_mq_end_request(rq, error);
  77                 return 0;
  78         }
  79 
  80         return 1;
  81 }
  82 EXPORT_SYMBOL_GPL(ide_end_rq);
  83 
  84 void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err)
  85 {
  86         const struct ide_tp_ops *tp_ops = drive->hwif->tp_ops;
  87         struct ide_taskfile *tf = &cmd->tf;
  88         struct request *rq = cmd->rq;
  89         u8 tf_cmd = tf->command;
  90 
  91         tf->error = err;
  92         tf->status = stat;
  93 
  94         if (cmd->ftf_flags & IDE_FTFLAG_IN_DATA) {
  95                 u8 data[2];
  96 
  97                 tp_ops->input_data(drive, cmd, data, 2);
  98 
  99                 cmd->tf.data  = data[0];
 100                 cmd->hob.data = data[1];
 101         }
 102 
 103         ide_tf_readback(drive, cmd);
 104 
 105         if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) &&
 106             tf_cmd == ATA_CMD_IDLEIMMEDIATE) {
 107                 if (tf->lbal != 0xc4) {
 108                         printk(KERN_ERR "%s: head unload failed!\n",
 109                                drive->name);
 110                         ide_tf_dump(drive->name, cmd);
 111                 } else
 112                         drive->dev_flags |= IDE_DFLAG_PARKED;
 113         }
 114 
 115         if (rq && ata_taskfile_request(rq)) {
 116                 struct ide_cmd *orig_cmd = ide_req(rq)->special;
 117 
 118                 if (cmd->tf_flags & IDE_TFLAG_DYN)
 119                         kfree(orig_cmd);
 120                 else if (cmd != orig_cmd)
 121                         memcpy(orig_cmd, cmd, sizeof(*cmd));
 122         }
 123 }
 124 
 125 int ide_complete_rq(ide_drive_t *drive, blk_status_t error, unsigned int nr_bytes)
 126 {
 127         ide_hwif_t *hwif = drive->hwif;
 128         struct request *rq = hwif->rq;
 129         int rc;
 130 
 131         /*
 132          * if failfast is set on a request, override number of sectors
 133          * and complete the whole request right now
 134          */
 135         if (blk_noretry_request(rq) && error)
 136                 nr_bytes = blk_rq_sectors(rq) << 9;
 137 
 138         rc = ide_end_rq(drive, rq, error, nr_bytes);
 139         if (rc == 0)
 140                 hwif->rq = NULL;
 141 
 142         return rc;
 143 }
 144 EXPORT_SYMBOL(ide_complete_rq);
 145 
 146 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
 147 {
 148         u8 drv_req = ata_misc_request(rq) && rq->rq_disk;
 149         u8 media = drive->media;
 150 
 151         drive->failed_pc = NULL;
 152 
 153         if ((media == ide_floppy || media == ide_tape) && drv_req) {
 154                 scsi_req(rq)->result = 0;
 155         } else {
 156                 if (media == ide_tape)
 157                         scsi_req(rq)->result = IDE_DRV_ERROR_GENERAL;
 158                 else if (blk_rq_is_passthrough(rq) && scsi_req(rq)->result == 0)
 159                         scsi_req(rq)->result = -EIO;
 160         }
 161 
 162         ide_complete_rq(drive, BLK_STS_IOERR, blk_rq_bytes(rq));
 163 }
 164 
 165 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 166 {
 167         tf->nsect   = drive->sect;
 168         tf->lbal    = drive->sect;
 169         tf->lbam    = drive->cyl;
 170         tf->lbah    = drive->cyl >> 8;
 171         tf->device  = (drive->head - 1) | drive->select;
 172         tf->command = ATA_CMD_INIT_DEV_PARAMS;
 173 }
 174 
 175 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 176 {
 177         tf->nsect   = drive->sect;
 178         tf->command = ATA_CMD_RESTORE;
 179 }
 180 
 181 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
 182 {
 183         tf->nsect   = drive->mult_req;
 184         tf->command = ATA_CMD_SET_MULTI;
 185 }
 186 
 187 /**
 188  *      do_special              -       issue some special commands
 189  *      @drive: drive the command is for
 190  *
 191  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
 192  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
 193  */
 194 
 195 static ide_startstop_t do_special(ide_drive_t *drive)
 196 {
 197         struct ide_cmd cmd;
 198 
 199 #ifdef DEBUG
 200         printk(KERN_DEBUG "%s: %s: 0x%02x\n", drive->name, __func__,
 201                 drive->special_flags);
 202 #endif
 203         if (drive->media != ide_disk) {
 204                 drive->special_flags = 0;
 205                 drive->mult_req = 0;
 206                 return ide_stopped;
 207         }
 208 
 209         memset(&cmd, 0, sizeof(cmd));
 210         cmd.protocol = ATA_PROT_NODATA;
 211 
 212         if (drive->special_flags & IDE_SFLAG_SET_GEOMETRY) {
 213                 drive->special_flags &= ~IDE_SFLAG_SET_GEOMETRY;
 214                 ide_tf_set_specify_cmd(drive, &cmd.tf);
 215         } else if (drive->special_flags & IDE_SFLAG_RECALIBRATE) {
 216                 drive->special_flags &= ~IDE_SFLAG_RECALIBRATE;
 217                 ide_tf_set_restore_cmd(drive, &cmd.tf);
 218         } else if (drive->special_flags & IDE_SFLAG_SET_MULTMODE) {
 219                 drive->special_flags &= ~IDE_SFLAG_SET_MULTMODE;
 220                 ide_tf_set_setmult_cmd(drive, &cmd.tf);
 221         } else
 222                 BUG();
 223 
 224         cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
 225         cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
 226         cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER;
 227 
 228         do_rw_taskfile(drive, &cmd);
 229 
 230         return ide_started;
 231 }
 232 
 233 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
 234 {
 235         ide_hwif_t *hwif = drive->hwif;
 236         struct scatterlist *sg = hwif->sg_table;
 237         struct request *rq = cmd->rq;
 238 
 239         cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
 240 }
 241 EXPORT_SYMBOL_GPL(ide_map_sg);
 242 
 243 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
 244 {
 245         cmd->nbytes = cmd->nleft = nr_bytes;
 246         cmd->cursg_ofs = 0;
 247         cmd->cursg = NULL;
 248 }
 249 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
 250 
 251 /**
 252  *      execute_drive_command   -       issue special drive command
 253  *      @drive: the drive to issue the command on
 254  *      @rq: the request structure holding the command
 255  *
 256  *      execute_drive_cmd() issues a special drive command,  usually 
 257  *      initiated by ioctl() from the external hdparm program. The
 258  *      command can be a drive command, drive task or taskfile 
 259  *      operation. Weirdly you can call it with NULL to wait for
 260  *      all commands to finish. Don't do this as that is due to change
 261  */
 262 
 263 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
 264                 struct request *rq)
 265 {
 266         struct ide_cmd *cmd = ide_req(rq)->special;
 267 
 268         if (cmd) {
 269                 if (cmd->protocol == ATA_PROT_PIO) {
 270                         ide_init_sg_cmd(cmd, blk_rq_sectors(rq) << 9);
 271                         ide_map_sg(drive, cmd);
 272                 }
 273 
 274                 return do_rw_taskfile(drive, cmd);
 275         }
 276 
 277         /*
 278          * NULL is actually a valid way of waiting for
 279          * all current requests to be flushed from the queue.
 280          */
 281 #ifdef DEBUG
 282         printk("%s: DRIVE_CMD (null)\n", drive->name);
 283 #endif
 284         scsi_req(rq)->result = 0;
 285         ide_complete_rq(drive, BLK_STS_OK, blk_rq_bytes(rq));
 286 
 287         return ide_stopped;
 288 }
 289 
 290 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 291 {
 292         u8 cmd = scsi_req(rq)->cmd[0];
 293 
 294         switch (cmd) {
 295         case REQ_PARK_HEADS:
 296         case REQ_UNPARK_HEADS:
 297                 return ide_do_park_unpark(drive, rq);
 298         case REQ_DEVSET_EXEC:
 299                 return ide_do_devset(drive, rq);
 300         case REQ_DRIVE_RESET:
 301                 return ide_do_reset(drive);
 302         default:
 303                 BUG();
 304         }
 305 }
 306 
 307 /**
 308  *      start_request   -       start of I/O and command issuing for IDE
 309  *
 310  *      start_request() initiates handling of a new I/O request. It
 311  *      accepts commands and I/O (read/write) requests.
 312  *
 313  *      FIXME: this function needs a rename
 314  */
 315  
 316 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
 317 {
 318         ide_startstop_t startstop;
 319 
 320 #ifdef DEBUG
 321         printk("%s: start_request: current=0x%08lx\n",
 322                 drive->hwif->name, (unsigned long) rq);
 323 #endif
 324 
 325         /* bail early if we've exceeded max_failures */
 326         if (drive->max_failures && (drive->failures > drive->max_failures)) {
 327                 rq->rq_flags |= RQF_FAILED;
 328                 goto kill_rq;
 329         }
 330 
 331         if (drive->prep_rq && !drive->prep_rq(drive, rq))
 332                 return ide_stopped;
 333 
 334         if (ata_pm_request(rq))
 335                 ide_check_pm_state(drive, rq);
 336 
 337         drive->hwif->tp_ops->dev_select(drive);
 338         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
 339                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
 340                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
 341                 return startstop;
 342         }
 343 
 344         if (drive->special_flags == 0) {
 345                 struct ide_driver *drv;
 346 
 347                 /*
 348                  * We reset the drive so we need to issue a SETFEATURES.
 349                  * Do it _after_ do_special() restored device parameters.
 350                  */
 351                 if (drive->current_speed == 0xff)
 352                         ide_config_drive_speed(drive, drive->desired_speed);
 353 
 354                 if (ata_taskfile_request(rq))
 355                         return execute_drive_cmd(drive, rq);
 356                 else if (ata_pm_request(rq)) {
 357                         struct ide_pm_state *pm = ide_req(rq)->special;
 358 #ifdef DEBUG_PM
 359                         printk("%s: start_power_step(step: %d)\n",
 360                                 drive->name, pm->pm_step);
 361 #endif
 362                         startstop = ide_start_power_step(drive, rq);
 363                         if (startstop == ide_stopped &&
 364                             pm->pm_step == IDE_PM_COMPLETED)
 365                                 ide_complete_pm_rq(drive, rq);
 366                         return startstop;
 367                 } else if (!rq->rq_disk && ata_misc_request(rq))
 368                         /*
 369                          * TODO: Once all ULDs have been modified to
 370                          * check for specific op codes rather than
 371                          * blindly accepting any special request, the
 372                          * check for ->rq_disk above may be replaced
 373                          * by a more suitable mechanism or even
 374                          * dropped entirely.
 375                          */
 376                         return ide_special_rq(drive, rq);
 377 
 378                 drv = *(struct ide_driver **)rq->rq_disk->private_data;
 379 
 380                 return drv->do_request(drive, rq, blk_rq_pos(rq));
 381         }
 382         return do_special(drive);
 383 kill_rq:
 384         ide_kill_rq(drive, rq);
 385         return ide_stopped;
 386 }
 387 
 388 /**
 389  *      ide_stall_queue         -       pause an IDE device
 390  *      @drive: drive to stall
 391  *      @timeout: time to stall for (jiffies)
 392  *
 393  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
 394  *      to the port by sleeping for timeout jiffies.
 395  */
 396  
 397 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 398 {
 399         if (timeout > WAIT_WORSTCASE)
 400                 timeout = WAIT_WORSTCASE;
 401         drive->sleep = timeout + jiffies;
 402         drive->dev_flags |= IDE_DFLAG_SLEEPING;
 403 }
 404 EXPORT_SYMBOL(ide_stall_queue);
 405 
 406 static inline int ide_lock_port(ide_hwif_t *hwif)
 407 {
 408         if (hwif->busy)
 409                 return 1;
 410 
 411         hwif->busy = 1;
 412 
 413         return 0;
 414 }
 415 
 416 static inline void ide_unlock_port(ide_hwif_t *hwif)
 417 {
 418         hwif->busy = 0;
 419 }
 420 
 421 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
 422 {
 423         int rc = 0;
 424 
 425         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 426                 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
 427                 if (rc == 0) {
 428                         if (host->get_lock)
 429                                 host->get_lock(ide_intr, hwif);
 430                 }
 431         }
 432         return rc;
 433 }
 434 
 435 static inline void ide_unlock_host(struct ide_host *host)
 436 {
 437         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 438                 if (host->release_lock)
 439                         host->release_lock();
 440                 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
 441         }
 442 }
 443 
 444 void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
 445 {
 446         struct request_queue *q = drive->queue;
 447 
 448         /* Use 3ms as that was the old plug delay */
 449         if (rq) {
 450                 blk_mq_requeue_request(rq, false);
 451                 blk_mq_delay_kick_requeue_list(q, 3);
 452         } else
 453                 blk_mq_delay_run_hw_queue(q->queue_hw_ctx[0], 3);
 454 }
 455 
 456 blk_status_t ide_issue_rq(ide_drive_t *drive, struct request *rq,
 457                           bool local_requeue)
 458 {
 459         ide_hwif_t *hwif = drive->hwif;
 460         struct ide_host *host = hwif->host;
 461         ide_startstop_t startstop;
 462 
 463         if (!blk_rq_is_passthrough(rq) && !(rq->rq_flags & RQF_DONTPREP)) {
 464                 rq->rq_flags |= RQF_DONTPREP;
 465                 ide_req(rq)->special = NULL;
 466         }
 467 
 468         /* HLD do_request() callback might sleep, make sure it's okay */
 469         might_sleep();
 470 
 471         if (ide_lock_host(host, hwif))
 472                 return BLK_STS_DEV_RESOURCE;
 473 
 474         spin_lock_irq(&hwif->lock);
 475 
 476         if (!ide_lock_port(hwif)) {
 477                 ide_hwif_t *prev_port;
 478 
 479                 WARN_ON_ONCE(hwif->rq);
 480 repeat:
 481                 prev_port = hwif->host->cur_port;
 482                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
 483                     time_after(drive->sleep, jiffies)) {
 484                         ide_unlock_port(hwif);
 485                         goto plug_device;
 486                 }
 487 
 488                 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
 489                     hwif != prev_port) {
 490                         ide_drive_t *cur_dev =
 491                                 prev_port ? prev_port->cur_dev : NULL;
 492 
 493                         /*
 494                          * set nIEN for previous port, drives in the
 495                          * quirk list may not like intr setups/cleanups
 496                          */
 497                         if (cur_dev &&
 498                             (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
 499                                 prev_port->tp_ops->write_devctl(prev_port,
 500                                                                 ATA_NIEN |
 501                                                                 ATA_DEVCTL_OBS);
 502 
 503                         hwif->host->cur_port = hwif;
 504                 }
 505                 hwif->cur_dev = drive;
 506                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
 507 
 508                 /*
 509                  * Sanity: don't accept a request that isn't a PM request
 510                  * if we are currently power managed. This is very important as
 511                  * blk_stop_queue() doesn't prevent the blk_fetch_request()
 512                  * above to return us whatever is in the queue. Since we call
 513                  * ide_do_request() ourselves, we end up taking requests while
 514                  * the queue is blocked...
 515                  * 
 516                  * We let requests forced at head of queue with ide-preempt
 517                  * though. I hope that doesn't happen too much, hopefully not
 518                  * unless the subdriver triggers such a thing in its own PM
 519                  * state machine.
 520                  */
 521                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
 522                     ata_pm_request(rq) == 0 &&
 523                     (rq->rq_flags & RQF_PREEMPT) == 0) {
 524                         /* there should be no pending command at this point */
 525                         ide_unlock_port(hwif);
 526                         goto plug_device;
 527                 }
 528 
 529                 scsi_req(rq)->resid_len = blk_rq_bytes(rq);
 530                 hwif->rq = rq;
 531 
 532                 spin_unlock_irq(&hwif->lock);
 533                 startstop = start_request(drive, rq);
 534                 spin_lock_irq(&hwif->lock);
 535 
 536                 if (startstop == ide_stopped) {
 537                         rq = hwif->rq;
 538                         hwif->rq = NULL;
 539                         if (rq)
 540                                 goto repeat;
 541                         ide_unlock_port(hwif);
 542                         goto out;
 543                 }
 544         } else {
 545 plug_device:
 546                 if (local_requeue)
 547                         list_add(&rq->queuelist, &drive->rq_list);
 548                 spin_unlock_irq(&hwif->lock);
 549                 ide_unlock_host(host);
 550                 if (!local_requeue)
 551                         ide_requeue_and_plug(drive, rq);
 552                 return BLK_STS_OK;
 553         }
 554 
 555 out:
 556         spin_unlock_irq(&hwif->lock);
 557         if (rq == NULL)
 558                 ide_unlock_host(host);
 559         return BLK_STS_OK;
 560 }
 561 
 562 /*
 563  * Issue a new request to a device.
 564  */
 565 blk_status_t ide_queue_rq(struct blk_mq_hw_ctx *hctx,
 566                           const struct blk_mq_queue_data *bd)
 567 {
 568         ide_drive_t *drive = hctx->queue->queuedata;
 569         ide_hwif_t *hwif = drive->hwif;
 570 
 571         spin_lock_irq(&hwif->lock);
 572         if (drive->sense_rq_active) {
 573                 spin_unlock_irq(&hwif->lock);
 574                 return BLK_STS_DEV_RESOURCE;
 575         }
 576         spin_unlock_irq(&hwif->lock);
 577 
 578         blk_mq_start_request(bd->rq);
 579         return ide_issue_rq(drive, bd->rq, false);
 580 }
 581 
 582 static int drive_is_ready(ide_drive_t *drive)
 583 {
 584         ide_hwif_t *hwif = drive->hwif;
 585         u8 stat = 0;
 586 
 587         if (drive->waiting_for_dma)
 588                 return hwif->dma_ops->dma_test_irq(drive);
 589 
 590         if (hwif->io_ports.ctl_addr &&
 591             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
 592                 stat = hwif->tp_ops->read_altstatus(hwif);
 593         else
 594                 /* Note: this may clear a pending IRQ!! */
 595                 stat = hwif->tp_ops->read_status(hwif);
 596 
 597         if (stat & ATA_BUSY)
 598                 /* drive busy: definitely not interrupting */
 599                 return 0;
 600 
 601         /* drive ready: *might* be interrupting */
 602         return 1;
 603 }
 604 
 605 /**
 606  *      ide_timer_expiry        -       handle lack of an IDE interrupt
 607  *      @data: timer callback magic (hwif)
 608  *
 609  *      An IDE command has timed out before the expected drive return
 610  *      occurred. At this point we attempt to clean up the current
 611  *      mess. If the current handler includes an expiry handler then
 612  *      we invoke the expiry handler, and providing it is happy the
 613  *      work is done. If that fails we apply generic recovery rules
 614  *      invoking the handler and checking the drive DMA status. We
 615  *      have an excessively incestuous relationship with the DMA
 616  *      logic that wants cleaning up.
 617  */
 618  
 619 void ide_timer_expiry (struct timer_list *t)
 620 {
 621         ide_hwif_t      *hwif = from_timer(hwif, t, timer);
 622         ide_drive_t     *uninitialized_var(drive);
 623         ide_handler_t   *handler;
 624         unsigned long   flags;
 625         int             wait = -1;
 626         int             plug_device = 0;
 627         struct request  *uninitialized_var(rq_in_flight);
 628 
 629         spin_lock_irqsave(&hwif->lock, flags);
 630 
 631         handler = hwif->handler;
 632 
 633         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
 634                 /*
 635                  * Either a marginal timeout occurred
 636                  * (got the interrupt just as timer expired),
 637                  * or we were "sleeping" to give other devices a chance.
 638                  * Either way, we don't really want to complain about anything.
 639                  */
 640         } else {
 641                 ide_expiry_t *expiry = hwif->expiry;
 642                 ide_startstop_t startstop = ide_stopped;
 643 
 644                 drive = hwif->cur_dev;
 645 
 646                 if (expiry) {
 647                         wait = expiry(drive);
 648                         if (wait > 0) { /* continue */
 649                                 /* reset timer */
 650                                 hwif->timer.expires = jiffies + wait;
 651                                 hwif->req_gen_timer = hwif->req_gen;
 652                                 add_timer(&hwif->timer);
 653                                 spin_unlock_irqrestore(&hwif->lock, flags);
 654                                 return;
 655                         }
 656                 }
 657                 hwif->handler = NULL;
 658                 hwif->expiry = NULL;
 659                 /*
 660                  * We need to simulate a real interrupt when invoking
 661                  * the handler() function, which means we need to
 662                  * globally mask the specific IRQ:
 663                  */
 664                 spin_unlock(&hwif->lock);
 665                 /* disable_irq_nosync ?? */
 666                 disable_irq(hwif->irq);
 667 
 668                 if (hwif->polling) {
 669                         startstop = handler(drive);
 670                 } else if (drive_is_ready(drive)) {
 671                         if (drive->waiting_for_dma)
 672                                 hwif->dma_ops->dma_lost_irq(drive);
 673                         if (hwif->port_ops && hwif->port_ops->clear_irq)
 674                                 hwif->port_ops->clear_irq(drive);
 675 
 676                         printk(KERN_WARNING "%s: lost interrupt\n",
 677                                 drive->name);
 678                         startstop = handler(drive);
 679                 } else {
 680                         if (drive->waiting_for_dma)
 681                                 startstop = ide_dma_timeout_retry(drive, wait);
 682                         else
 683                                 startstop = ide_error(drive, "irq timeout",
 684                                         hwif->tp_ops->read_status(hwif));
 685                 }
 686                 /* Disable interrupts again, `handler' might have enabled it */
 687                 spin_lock_irq(&hwif->lock);
 688                 enable_irq(hwif->irq);
 689                 if (startstop == ide_stopped && hwif->polling == 0) {
 690                         rq_in_flight = hwif->rq;
 691                         hwif->rq = NULL;
 692                         ide_unlock_port(hwif);
 693                         plug_device = 1;
 694                 }
 695         }
 696         spin_unlock_irqrestore(&hwif->lock, flags);
 697 
 698         if (plug_device) {
 699                 ide_unlock_host(hwif->host);
 700                 ide_requeue_and_plug(drive, rq_in_flight);
 701         }
 702 }
 703 
 704 /**
 705  *      unexpected_intr         -       handle an unexpected IDE interrupt
 706  *      @irq: interrupt line
 707  *      @hwif: port being processed
 708  *
 709  *      There's nothing really useful we can do with an unexpected interrupt,
 710  *      other than reading the status register (to clear it), and logging it.
 711  *      There should be no way that an irq can happen before we're ready for it,
 712  *      so we needn't worry much about losing an "important" interrupt here.
 713  *
 714  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 715  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
 716  *      looks "good", we just ignore the interrupt completely.
 717  *
 718  *      This routine assumes __cli() is in effect when called.
 719  *
 720  *      If an unexpected interrupt happens on irq15 while we are handling irq14
 721  *      and if the two interfaces are "serialized" (CMD640), then it looks like
 722  *      we could screw up by interfering with a new request being set up for 
 723  *      irq15.
 724  *
 725  *      In reality, this is a non-issue.  The new command is not sent unless 
 726  *      the drive is ready to accept one, in which case we know the drive is
 727  *      not trying to interrupt us.  And ide_set_handler() is always invoked
 728  *      before completing the issuance of any new drive command, so we will not
 729  *      be accidentally invoked as a result of any valid command completion
 730  *      interrupt.
 731  */
 732 
 733 static void unexpected_intr(int irq, ide_hwif_t *hwif)
 734 {
 735         u8 stat = hwif->tp_ops->read_status(hwif);
 736 
 737         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
 738                 /* Try to not flood the console with msgs */
 739                 static unsigned long last_msgtime, count;
 740                 ++count;
 741 
 742                 if (time_after(jiffies, last_msgtime + HZ)) {
 743                         last_msgtime = jiffies;
 744                         printk(KERN_ERR "%s: unexpected interrupt, "
 745                                 "status=0x%02x, count=%ld\n",
 746                                 hwif->name, stat, count);
 747                 }
 748         }
 749 }
 750 
 751 /**
 752  *      ide_intr        -       default IDE interrupt handler
 753  *      @irq: interrupt number
 754  *      @dev_id: hwif
 755  *      @regs: unused weirdness from the kernel irq layer
 756  *
 757  *      This is the default IRQ handler for the IDE layer. You should
 758  *      not need to override it. If you do be aware it is subtle in
 759  *      places
 760  *
 761  *      hwif is the interface in the group currently performing
 762  *      a command. hwif->cur_dev is the drive and hwif->handler is
 763  *      the IRQ handler to call. As we issue a command the handlers
 764  *      step through multiple states, reassigning the handler to the
 765  *      next step in the process. Unlike a smart SCSI controller IDE
 766  *      expects the main processor to sequence the various transfer
 767  *      stages. We also manage a poll timer to catch up with most
 768  *      timeout situations. There are still a few where the handlers
 769  *      don't ever decide to give up.
 770  *
 771  *      The handler eventually returns ide_stopped to indicate the
 772  *      request completed. At this point we issue the next request
 773  *      on the port and the process begins again.
 774  */
 775 
 776 irqreturn_t ide_intr (int irq, void *dev_id)
 777 {
 778         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
 779         struct ide_host *host = hwif->host;
 780         ide_drive_t *uninitialized_var(drive);
 781         ide_handler_t *handler;
 782         unsigned long flags;
 783         ide_startstop_t startstop;
 784         irqreturn_t irq_ret = IRQ_NONE;
 785         int plug_device = 0;
 786         struct request *uninitialized_var(rq_in_flight);
 787 
 788         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
 789                 if (hwif != host->cur_port)
 790                         goto out_early;
 791         }
 792 
 793         spin_lock_irqsave(&hwif->lock, flags);
 794 
 795         if (hwif->port_ops && hwif->port_ops->test_irq &&
 796             hwif->port_ops->test_irq(hwif) == 0)
 797                 goto out;
 798 
 799         handler = hwif->handler;
 800 
 801         if (handler == NULL || hwif->polling) {
 802                 /*
 803                  * Not expecting an interrupt from this drive.
 804                  * That means this could be:
 805                  *      (1) an interrupt from another PCI device
 806                  *      sharing the same PCI INT# as us.
 807                  * or   (2) a drive just entered sleep or standby mode,
 808                  *      and is interrupting to let us know.
 809                  * or   (3) a spurious interrupt of unknown origin.
 810                  *
 811                  * For PCI, we cannot tell the difference,
 812                  * so in that case we just ignore it and hope it goes away.
 813                  */
 814                 if ((host->irq_flags & IRQF_SHARED) == 0) {
 815                         /*
 816                          * Probably not a shared PCI interrupt,
 817                          * so we can safely try to do something about it:
 818                          */
 819                         unexpected_intr(irq, hwif);
 820                 } else {
 821                         /*
 822                          * Whack the status register, just in case
 823                          * we have a leftover pending IRQ.
 824                          */
 825                         (void)hwif->tp_ops->read_status(hwif);
 826                 }
 827                 goto out;
 828         }
 829 
 830         drive = hwif->cur_dev;
 831 
 832         if (!drive_is_ready(drive))
 833                 /*
 834                  * This happens regularly when we share a PCI IRQ with
 835                  * another device.  Unfortunately, it can also happen
 836                  * with some buggy drives that trigger the IRQ before
 837                  * their status register is up to date.  Hopefully we have
 838                  * enough advance overhead that the latter isn't a problem.
 839                  */
 840                 goto out;
 841 
 842         hwif->handler = NULL;
 843         hwif->expiry = NULL;
 844         hwif->req_gen++;
 845         del_timer(&hwif->timer);
 846         spin_unlock(&hwif->lock);
 847 
 848         if (hwif->port_ops && hwif->port_ops->clear_irq)
 849                 hwif->port_ops->clear_irq(drive);
 850 
 851         if (drive->dev_flags & IDE_DFLAG_UNMASK)
 852                 local_irq_enable_in_hardirq();
 853 
 854         /* service this interrupt, may set handler for next interrupt */
 855         startstop = handler(drive);
 856 
 857         spin_lock_irq(&hwif->lock);
 858         /*
 859          * Note that handler() may have set things up for another
 860          * interrupt to occur soon, but it cannot happen until
 861          * we exit from this routine, because it will be the
 862          * same irq as is currently being serviced here, and Linux
 863          * won't allow another of the same (on any CPU) until we return.
 864          */
 865         if (startstop == ide_stopped && hwif->polling == 0) {
 866                 BUG_ON(hwif->handler);
 867                 rq_in_flight = hwif->rq;
 868                 hwif->rq = NULL;
 869                 ide_unlock_port(hwif);
 870                 plug_device = 1;
 871         }
 872         irq_ret = IRQ_HANDLED;
 873 out:
 874         spin_unlock_irqrestore(&hwif->lock, flags);
 875 out_early:
 876         if (plug_device) {
 877                 ide_unlock_host(hwif->host);
 878                 ide_requeue_and_plug(drive, rq_in_flight);
 879         }
 880 
 881         return irq_ret;
 882 }
 883 EXPORT_SYMBOL_GPL(ide_intr);
 884 
 885 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
 886 {
 887         ide_hwif_t *hwif = drive->hwif;
 888         u8 buf[4] = { 0 };
 889 
 890         while (len > 0) {
 891                 if (write)
 892                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
 893                 else
 894                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
 895                 len -= 4;
 896         }
 897 }
 898 EXPORT_SYMBOL_GPL(ide_pad_transfer);
 899 
 900 void ide_insert_request_head(ide_drive_t *drive, struct request *rq)
 901 {
 902         drive->sense_rq_active = true;
 903         list_add_tail(&rq->queuelist, &drive->rq_list);
 904         kblockd_schedule_work(&drive->rq_work);
 905 }
 906 EXPORT_SYMBOL_GPL(ide_insert_request_head);