ide-io.c revision 295f00042aaf6b553b5f37348f89bab463d4a469
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/hdreg.h> 44#include <linux/completion.h> 45#include <linux/reboot.h> 46#include <linux/cdrom.h> 47#include <linux/seq_file.h> 48#include <linux/device.h> 49#include <linux/kmod.h> 50#include <linux/scatterlist.h> 51#include <linux/bitops.h> 52 53#include <asm/byteorder.h> 54#include <asm/irq.h> 55#include <asm/uaccess.h> 56#include <asm/io.h> 57 58static int __ide_end_request(ide_drive_t *drive, struct request *rq, 59 int uptodate, unsigned int nr_bytes, int dequeue) 60{ 61 int ret = 1; 62 int error = 0; 63 64 if (uptodate <= 0) 65 error = uptodate ? uptodate : -EIO; 66 67 /* 68 * if failfast is set on a request, override number of sectors and 69 * complete the whole request right now 70 */ 71 if (blk_noretry_request(rq) && error) 72 nr_bytes = rq->hard_nr_sectors << 9; 73 74 if (!blk_fs_request(rq) && error && !rq->errors) 75 rq->errors = -EIO; 76 77 /* 78 * decide whether to reenable DMA -- 3 is a random magic for now, 79 * if we DMA timeout more than 3 times, just stay in PIO 80 */ 81 if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) && 82 drive->retry_pio <= 3) { 83 drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY; 84 ide_dma_on(drive); 85 } 86 87 if (!blk_end_request(rq, error, nr_bytes)) 88 ret = 0; 89 90 if (ret == 0 && dequeue) 91 drive->hwif->hwgroup->rq = NULL; 92 93 return ret; 94} 95 96/** 97 * ide_end_request - complete an IDE I/O 98 * @drive: IDE device for the I/O 99 * @uptodate: 100 * @nr_sectors: number of sectors completed 101 * 102 * This is our end_request wrapper function. We complete the I/O 103 * update random number input and dequeue the request, which if 104 * it was tagged may be out of order. 105 */ 106 107int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors) 108{ 109 unsigned int nr_bytes = nr_sectors << 9; 110 struct request *rq = drive->hwif->hwgroup->rq; 111 112 if (!nr_bytes) { 113 if (blk_pc_request(rq)) 114 nr_bytes = rq->data_len; 115 else 116 nr_bytes = rq->hard_cur_sectors << 9; 117 } 118 119 return __ide_end_request(drive, rq, uptodate, nr_bytes, 1); 120} 121EXPORT_SYMBOL(ide_end_request); 122 123/** 124 * ide_end_dequeued_request - complete an IDE I/O 125 * @drive: IDE device for the I/O 126 * @uptodate: 127 * @nr_sectors: number of sectors completed 128 * 129 * Complete an I/O that is no longer on the request queue. This 130 * typically occurs when we pull the request and issue a REQUEST_SENSE. 131 * We must still finish the old request but we must not tamper with the 132 * queue in the meantime. 133 * 134 * NOTE: This path does not handle barrier, but barrier is not supported 135 * on ide-cd anyway. 136 */ 137 138int ide_end_dequeued_request(ide_drive_t *drive, struct request *rq, 139 int uptodate, int nr_sectors) 140{ 141 BUG_ON(!blk_rq_started(rq)); 142 143 return __ide_end_request(drive, rq, uptodate, nr_sectors << 9, 0); 144} 145EXPORT_SYMBOL_GPL(ide_end_dequeued_request); 146 147/** 148 * ide_end_drive_cmd - end an explicit drive command 149 * @drive: command 150 * @stat: status bits 151 * @err: error bits 152 * 153 * Clean up after success/failure of an explicit drive command. 154 * These get thrown onto the queue so they are synchronized with 155 * real I/O operations on the drive. 156 * 157 * In LBA48 mode we have to read the register set twice to get 158 * all the extra information out. 159 */ 160 161void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err) 162{ 163 ide_hwgroup_t *hwgroup = drive->hwif->hwgroup; 164 struct request *rq = hwgroup->rq; 165 166 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) { 167 ide_task_t *task = (ide_task_t *)rq->special; 168 169 if (task) { 170 struct ide_taskfile *tf = &task->tf; 171 172 tf->error = err; 173 tf->status = stat; 174 175 drive->hwif->tp_ops->tf_read(drive, task); 176 177 if (task->tf_flags & IDE_TFLAG_DYN) 178 kfree(task); 179 } 180 } else if (blk_pm_request(rq)) { 181 struct request_pm_state *pm = rq->data; 182 183 ide_complete_power_step(drive, rq); 184 if (pm->pm_step == IDE_PM_COMPLETED) 185 ide_complete_pm_request(drive, rq); 186 return; 187 } 188 189 hwgroup->rq = NULL; 190 191 rq->errors = err; 192 193 if (unlikely(blk_end_request(rq, (rq->errors ? -EIO : 0), 194 blk_rq_bytes(rq)))) 195 BUG(); 196} 197EXPORT_SYMBOL(ide_end_drive_cmd); 198 199static void ide_kill_rq(ide_drive_t *drive, struct request *rq) 200{ 201 if (rq->rq_disk) { 202 ide_driver_t *drv; 203 204 drv = *(ide_driver_t **)rq->rq_disk->private_data; 205 drv->end_request(drive, 0, 0); 206 } else 207 ide_end_request(drive, 0, 0); 208} 209 210static ide_startstop_t ide_ata_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err) 211{ 212 ide_hwif_t *hwif = drive->hwif; 213 214 if ((stat & ATA_BUSY) || 215 ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) { 216 /* other bits are useless when BUSY */ 217 rq->errors |= ERROR_RESET; 218 } else if (stat & ATA_ERR) { 219 /* err has different meaning on cdrom and tape */ 220 if (err == ATA_ABORTED) { 221 if ((drive->dev_flags & IDE_DFLAG_LBA) && 222 /* some newer drives don't support ATA_CMD_INIT_DEV_PARAMS */ 223 hwif->tp_ops->read_status(hwif) == ATA_CMD_INIT_DEV_PARAMS) 224 return ide_stopped; 225 } else if ((err & BAD_CRC) == BAD_CRC) { 226 /* UDMA crc error, just retry the operation */ 227 drive->crc_count++; 228 } else if (err & (ATA_BBK | ATA_UNC)) { 229 /* retries won't help these */ 230 rq->errors = ERROR_MAX; 231 } else if (err & ATA_TRK0NF) { 232 /* help it find track zero */ 233 rq->errors |= ERROR_RECAL; 234 } 235 } 236 237 if ((stat & ATA_DRQ) && rq_data_dir(rq) == READ && 238 (hwif->host_flags & IDE_HFLAG_ERROR_STOPS_FIFO) == 0) { 239 int nsect = drive->mult_count ? drive->mult_count : 1; 240 241 ide_pad_transfer(drive, READ, nsect * SECTOR_SIZE); 242 } 243 244 if (rq->errors >= ERROR_MAX || blk_noretry_request(rq)) { 245 ide_kill_rq(drive, rq); 246 return ide_stopped; 247 } 248 249 if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ)) 250 rq->errors |= ERROR_RESET; 251 252 if ((rq->errors & ERROR_RESET) == ERROR_RESET) { 253 ++rq->errors; 254 return ide_do_reset(drive); 255 } 256 257 if ((rq->errors & ERROR_RECAL) == ERROR_RECAL) 258 drive->special.b.recalibrate = 1; 259 260 ++rq->errors; 261 262 return ide_stopped; 263} 264 265static ide_startstop_t ide_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err) 266{ 267 ide_hwif_t *hwif = drive->hwif; 268 269 if ((stat & ATA_BUSY) || 270 ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) { 271 /* other bits are useless when BUSY */ 272 rq->errors |= ERROR_RESET; 273 } else { 274 /* add decoding error stuff */ 275 } 276 277 if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ)) 278 /* force an abort */ 279 hwif->tp_ops->exec_command(hwif, ATA_CMD_IDLEIMMEDIATE); 280 281 if (rq->errors >= ERROR_MAX) { 282 ide_kill_rq(drive, rq); 283 } else { 284 if ((rq->errors & ERROR_RESET) == ERROR_RESET) { 285 ++rq->errors; 286 return ide_do_reset(drive); 287 } 288 ++rq->errors; 289 } 290 291 return ide_stopped; 292} 293 294ide_startstop_t 295__ide_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err) 296{ 297 if (drive->media == ide_disk) 298 return ide_ata_error(drive, rq, stat, err); 299 return ide_atapi_error(drive, rq, stat, err); 300} 301 302EXPORT_SYMBOL_GPL(__ide_error); 303 304/** 305 * ide_error - handle an error on the IDE 306 * @drive: drive the error occurred on 307 * @msg: message to report 308 * @stat: status bits 309 * 310 * ide_error() takes action based on the error returned by the drive. 311 * For normal I/O that may well include retries. We deal with 312 * both new-style (taskfile) and old style command handling here. 313 * In the case of taskfile command handling there is work left to 314 * do 315 */ 316 317ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat) 318{ 319 struct request *rq; 320 u8 err; 321 322 err = ide_dump_status(drive, msg, stat); 323 324 if ((rq = HWGROUP(drive)->rq) == NULL) 325 return ide_stopped; 326 327 /* retry only "normal" I/O: */ 328 if (!blk_fs_request(rq)) { 329 rq->errors = 1; 330 ide_end_drive_cmd(drive, stat, err); 331 return ide_stopped; 332 } 333 334 if (rq->rq_disk) { 335 ide_driver_t *drv; 336 337 drv = *(ide_driver_t **)rq->rq_disk->private_data; 338 return drv->error(drive, rq, stat, err); 339 } else 340 return __ide_error(drive, rq, stat, err); 341} 342 343EXPORT_SYMBOL_GPL(ide_error); 344 345static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf) 346{ 347 tf->nsect = drive->sect; 348 tf->lbal = drive->sect; 349 tf->lbam = drive->cyl; 350 tf->lbah = drive->cyl >> 8; 351 tf->device = (drive->head - 1) | drive->select; 352 tf->command = ATA_CMD_INIT_DEV_PARAMS; 353} 354 355static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf) 356{ 357 tf->nsect = drive->sect; 358 tf->command = ATA_CMD_RESTORE; 359} 360 361static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf) 362{ 363 tf->nsect = drive->mult_req; 364 tf->command = ATA_CMD_SET_MULTI; 365} 366 367static ide_startstop_t ide_disk_special(ide_drive_t *drive) 368{ 369 special_t *s = &drive->special; 370 ide_task_t args; 371 372 memset(&args, 0, sizeof(ide_task_t)); 373 args.data_phase = TASKFILE_NO_DATA; 374 375 if (s->b.set_geometry) { 376 s->b.set_geometry = 0; 377 ide_tf_set_specify_cmd(drive, &args.tf); 378 } else if (s->b.recalibrate) { 379 s->b.recalibrate = 0; 380 ide_tf_set_restore_cmd(drive, &args.tf); 381 } else if (s->b.set_multmode) { 382 s->b.set_multmode = 0; 383 ide_tf_set_setmult_cmd(drive, &args.tf); 384 } else if (s->all) { 385 int special = s->all; 386 s->all = 0; 387 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special); 388 return ide_stopped; 389 } 390 391 args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE | 392 IDE_TFLAG_CUSTOM_HANDLER; 393 394 do_rw_taskfile(drive, &args); 395 396 return ide_started; 397} 398 399/** 400 * do_special - issue some special commands 401 * @drive: drive the command is for 402 * 403 * do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS, 404 * ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive. 405 * 406 * It used to do much more, but has been scaled back. 407 */ 408 409static ide_startstop_t do_special (ide_drive_t *drive) 410{ 411 special_t *s = &drive->special; 412 413#ifdef DEBUG 414 printk("%s: do_special: 0x%02x\n", drive->name, s->all); 415#endif 416 if (drive->media == ide_disk) 417 return ide_disk_special(drive); 418 419 s->all = 0; 420 drive->mult_req = 0; 421 return ide_stopped; 422} 423 424void ide_map_sg(ide_drive_t *drive, struct request *rq) 425{ 426 ide_hwif_t *hwif = drive->hwif; 427 struct scatterlist *sg = hwif->sg_table; 428 429 if (hwif->sg_mapped) /* needed by ide-scsi */ 430 return; 431 432 if (rq->cmd_type != REQ_TYPE_ATA_TASKFILE) { 433 hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg); 434 } else { 435 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE); 436 hwif->sg_nents = 1; 437 } 438} 439 440EXPORT_SYMBOL_GPL(ide_map_sg); 441 442void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq) 443{ 444 ide_hwif_t *hwif = drive->hwif; 445 446 hwif->nsect = hwif->nleft = rq->nr_sectors; 447 hwif->cursg_ofs = 0; 448 hwif->cursg = NULL; 449} 450 451EXPORT_SYMBOL_GPL(ide_init_sg_cmd); 452 453/** 454 * execute_drive_command - issue special drive command 455 * @drive: the drive to issue the command on 456 * @rq: the request structure holding the command 457 * 458 * execute_drive_cmd() issues a special drive command, usually 459 * initiated by ioctl() from the external hdparm program. The 460 * command can be a drive command, drive task or taskfile 461 * operation. Weirdly you can call it with NULL to wait for 462 * all commands to finish. Don't do this as that is due to change 463 */ 464 465static ide_startstop_t execute_drive_cmd (ide_drive_t *drive, 466 struct request *rq) 467{ 468 ide_hwif_t *hwif = HWIF(drive); 469 ide_task_t *task = rq->special; 470 471 if (task) { 472 hwif->data_phase = task->data_phase; 473 474 switch (hwif->data_phase) { 475 case TASKFILE_MULTI_OUT: 476 case TASKFILE_OUT: 477 case TASKFILE_MULTI_IN: 478 case TASKFILE_IN: 479 ide_init_sg_cmd(drive, rq); 480 ide_map_sg(drive, rq); 481 default: 482 break; 483 } 484 485 return do_rw_taskfile(drive, task); 486 } 487 488 /* 489 * NULL is actually a valid way of waiting for 490 * all current requests to be flushed from the queue. 491 */ 492#ifdef DEBUG 493 printk("%s: DRIVE_CMD (null)\n", drive->name); 494#endif 495 ide_end_drive_cmd(drive, hwif->tp_ops->read_status(hwif), 496 ide_read_error(drive)); 497 498 return ide_stopped; 499} 500 501int ide_devset_execute(ide_drive_t *drive, const struct ide_devset *setting, 502 int arg) 503{ 504 struct request_queue *q = drive->queue; 505 struct request *rq; 506 int ret = 0; 507 508 if (!(setting->flags & DS_SYNC)) 509 return setting->set(drive, arg); 510 511 rq = blk_get_request(q, READ, __GFP_WAIT); 512 rq->cmd_type = REQ_TYPE_SPECIAL; 513 rq->cmd_len = 5; 514 rq->cmd[0] = REQ_DEVSET_EXEC; 515 *(int *)&rq->cmd[1] = arg; 516 rq->special = setting->set; 517 518 if (blk_execute_rq(q, NULL, rq, 0)) 519 ret = rq->errors; 520 blk_put_request(rq); 521 522 return ret; 523} 524EXPORT_SYMBOL_GPL(ide_devset_execute); 525 526static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq) 527{ 528 u8 cmd = rq->cmd[0]; 529 530 if (cmd == REQ_PARK_HEADS || cmd == REQ_UNPARK_HEADS) { 531 ide_task_t task; 532 struct ide_taskfile *tf = &task.tf; 533 534 memset(&task, 0, sizeof(task)); 535 if (cmd == REQ_PARK_HEADS) { 536 drive->sleep = *(unsigned long *)rq->special; 537 drive->dev_flags |= IDE_DFLAG_SLEEPING; 538 tf->command = ATA_CMD_IDLEIMMEDIATE; 539 tf->feature = 0x44; 540 tf->lbal = 0x4c; 541 tf->lbam = 0x4e; 542 tf->lbah = 0x55; 543 task.tf_flags |= IDE_TFLAG_CUSTOM_HANDLER; 544 } else /* cmd == REQ_UNPARK_HEADS */ 545 tf->command = ATA_CMD_CHK_POWER; 546 547 task.tf_flags |= IDE_TFLAG_TF | IDE_TFLAG_DEVICE; 548 task.rq = rq; 549 drive->hwif->data_phase = task.data_phase = TASKFILE_NO_DATA; 550 return do_rw_taskfile(drive, &task); 551 } 552 553 switch (cmd) { 554 case REQ_DEVSET_EXEC: 555 { 556 int err, (*setfunc)(ide_drive_t *, int) = rq->special; 557 558 err = setfunc(drive, *(int *)&rq->cmd[1]); 559 if (err) 560 rq->errors = err; 561 else 562 err = 1; 563 ide_end_request(drive, err, 0); 564 return ide_stopped; 565 } 566 case REQ_DRIVE_RESET: 567 return ide_do_reset(drive); 568 default: 569 blk_dump_rq_flags(rq, "ide_special_rq - bad request"); 570 ide_end_request(drive, 0, 0); 571 return ide_stopped; 572 } 573} 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. 580 * 581 * FIXME: this function needs a rename 582 */ 583 584static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq) 585{ 586 ide_startstop_t startstop; 587 588 BUG_ON(!blk_rq_started(rq)); 589 590#ifdef DEBUG 591 printk("%s: start_request: current=0x%08lx\n", 592 HWIF(drive)->name, (unsigned long) rq); 593#endif 594 595 /* bail early if we've exceeded max_failures */ 596 if (drive->max_failures && (drive->failures > drive->max_failures)) { 597 rq->cmd_flags |= REQ_FAILED; 598 goto kill_rq; 599 } 600 601 if (blk_pm_request(rq)) 602 ide_check_pm_state(drive, rq); 603 604 SELECT_DRIVE(drive); 605 if (ide_wait_stat(&startstop, drive, drive->ready_stat, 606 ATA_BUSY | ATA_DRQ, WAIT_READY)) { 607 printk(KERN_ERR "%s: drive not ready for command\n", drive->name); 608 return startstop; 609 } 610 if (!drive->special.all) { 611 ide_driver_t *drv; 612 613 /* 614 * We reset the drive so we need to issue a SETFEATURES. 615 * Do it _after_ do_special() restored device parameters. 616 */ 617 if (drive->current_speed == 0xff) 618 ide_config_drive_speed(drive, drive->desired_speed); 619 620 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) 621 return execute_drive_cmd(drive, rq); 622 else if (blk_pm_request(rq)) { 623 struct request_pm_state *pm = rq->data; 624#ifdef DEBUG_PM 625 printk("%s: start_power_step(step: %d)\n", 626 drive->name, pm->pm_step); 627#endif 628 startstop = ide_start_power_step(drive, rq); 629 if (startstop == ide_stopped && 630 pm->pm_step == IDE_PM_COMPLETED) 631 ide_complete_pm_request(drive, rq); 632 return startstop; 633 } else if (!rq->rq_disk && blk_special_request(rq)) 634 /* 635 * TODO: Once all ULDs have been modified to 636 * check for specific op codes rather than 637 * blindly accepting any special request, the 638 * check for ->rq_disk above may be replaced 639 * by a more suitable mechanism or even 640 * dropped entirely. 641 */ 642 return ide_special_rq(drive, rq); 643 644 drv = *(ide_driver_t **)rq->rq_disk->private_data; 645 646 return drv->do_request(drive, rq, rq->sector); 647 } 648 return do_special(drive); 649kill_rq: 650 ide_kill_rq(drive, rq); 651 return ide_stopped; 652} 653 654/** 655 * ide_stall_queue - pause an IDE device 656 * @drive: drive to stall 657 * @timeout: time to stall for (jiffies) 658 * 659 * ide_stall_queue() can be used by a drive to give excess bandwidth back 660 * to the hwgroup by sleeping for timeout jiffies. 661 */ 662 663void ide_stall_queue (ide_drive_t *drive, unsigned long timeout) 664{ 665 if (timeout > WAIT_WORSTCASE) 666 timeout = WAIT_WORSTCASE; 667 drive->sleep = timeout + jiffies; 668 drive->dev_flags |= IDE_DFLAG_SLEEPING; 669} 670 671EXPORT_SYMBOL(ide_stall_queue); 672 673#define WAKEUP(drive) ((drive)->service_start + 2 * (drive)->service_time) 674 675/** 676 * choose_drive - select a drive to service 677 * @hwgroup: hardware group to select on 678 * 679 * choose_drive() selects the next drive which will be serviced. 680 * This is necessary because the IDE layer can't issue commands 681 * to both drives on the same cable, unlike SCSI. 682 */ 683 684static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup) 685{ 686 ide_drive_t *drive, *best; 687 688repeat: 689 best = NULL; 690 drive = hwgroup->drive; 691 692 /* 693 * drive is doing pre-flush, ordered write, post-flush sequence. even 694 * though that is 3 requests, it must be seen as a single transaction. 695 * we must not preempt this drive until that is complete 696 */ 697 if (blk_queue_flushing(drive->queue)) { 698 /* 699 * small race where queue could get replugged during 700 * the 3-request flush cycle, just yank the plug since 701 * we want it to finish asap 702 */ 703 blk_remove_plug(drive->queue); 704 return drive; 705 } 706 707 do { 708 u8 dev_s = !!(drive->dev_flags & IDE_DFLAG_SLEEPING); 709 u8 best_s = (best && !!(best->dev_flags & IDE_DFLAG_SLEEPING)); 710 711 if ((dev_s == 0 || time_after_eq(jiffies, drive->sleep)) && 712 !elv_queue_empty(drive->queue)) { 713 if (best == NULL || 714 (dev_s && (best_s == 0 || time_before(drive->sleep, best->sleep))) || 715 (best_s == 0 && time_before(WAKEUP(drive), WAKEUP(best)))) { 716 if (!blk_queue_plugged(drive->queue)) 717 best = drive; 718 } 719 } 720 } while ((drive = drive->next) != hwgroup->drive); 721 722 if (best && (best->dev_flags & IDE_DFLAG_NICE1) && 723 (best->dev_flags & IDE_DFLAG_SLEEPING) == 0 && 724 best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) { 725 long t = (signed long)(WAKEUP(best) - jiffies); 726 if (t >= WAIT_MIN_SLEEP) { 727 /* 728 * We *may* have some time to spare, but first let's see if 729 * someone can potentially benefit from our nice mood today.. 730 */ 731 drive = best->next; 732 do { 733 if ((drive->dev_flags & IDE_DFLAG_SLEEPING) == 0 734 && time_before(jiffies - best->service_time, WAKEUP(drive)) 735 && time_before(WAKEUP(drive), jiffies + t)) 736 { 737 ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP)); 738 goto repeat; 739 } 740 } while ((drive = drive->next) != best); 741 } 742 } 743 return best; 744} 745 746/* 747 * Issue a new request to a drive from hwgroup 748 * Caller must have already done spin_lock_irqsave(&hwgroup->lock, ..); 749 * 750 * A hwgroup is a serialized group of IDE interfaces. Usually there is 751 * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640) 752 * may have both interfaces in a single hwgroup to "serialize" access. 753 * Or possibly multiple ISA interfaces can share a common IRQ by being grouped 754 * together into one hwgroup for serialized access. 755 * 756 * Note also that several hwgroups can end up sharing a single IRQ, 757 * possibly along with many other devices. This is especially common in 758 * PCI-based systems with off-board IDE controller cards. 759 * 760 * The IDE driver uses a per-hwgroup spinlock to protect 761 * access to the request queues, and to protect the hwgroup->busy flag. 762 * 763 * The first thread into the driver for a particular hwgroup sets the 764 * hwgroup->busy flag to indicate that this hwgroup is now active, 765 * and then initiates processing of the top request from the request queue. 766 * 767 * Other threads attempting entry notice the busy setting, and will simply 768 * queue their new requests and exit immediately. Note that hwgroup->busy 769 * remains set even when the driver is merely awaiting the next interrupt. 770 * Thus, the meaning is "this hwgroup is busy processing a request". 771 * 772 * When processing of a request completes, the completing thread or IRQ-handler 773 * will start the next request from the queue. If no more work remains, 774 * the driver will clear the hwgroup->busy flag and exit. 775 * 776 * The per-hwgroup spinlock is used to protect all access to the 777 * hwgroup->busy flag, but is otherwise not needed for most processing in 778 * the driver. This makes the driver much more friendlier to shared IRQs 779 * than previous designs, while remaining 100% (?) SMP safe and capable. 780 */ 781void do_ide_request(struct request_queue *q) 782{ 783 ide_drive_t *orig_drive = q->queuedata; 784 ide_hwgroup_t *hwgroup = orig_drive->hwif->hwgroup; 785 ide_drive_t *drive; 786 ide_hwif_t *hwif; 787 struct request *rq; 788 ide_startstop_t startstop; 789 int loops = 0; 790 791 /* caller must own hwgroup->lock */ 792 BUG_ON(!irqs_disabled()); 793 794 while (!hwgroup->busy) { 795 hwgroup->busy = 1; 796 /* for atari only */ 797 ide_get_lock(ide_intr, hwgroup); 798 drive = choose_drive(hwgroup); 799 if (drive == NULL) { 800 int sleeping = 0; 801 unsigned long sleep = 0; /* shut up, gcc */ 802 hwgroup->rq = NULL; 803 drive = hwgroup->drive; 804 do { 805 if ((drive->dev_flags & IDE_DFLAG_SLEEPING) && 806 (sleeping == 0 || 807 time_before(drive->sleep, sleep))) { 808 sleeping = 1; 809 sleep = drive->sleep; 810 } 811 } while ((drive = drive->next) != hwgroup->drive); 812 if (sleeping) { 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 hwgroup->req_gen_timer = hwgroup->req_gen; 828 mod_timer(&hwgroup->timer, sleep); 829 /* we purposely leave hwgroup->busy==1 830 * while sleeping */ 831 } else { 832 /* Ugly, but how can we sleep for the lock 833 * otherwise? perhaps from tq_disk? 834 */ 835 836 /* for atari only */ 837 ide_release_lock(); 838 hwgroup->busy = 0; 839 } 840 841 /* no more work for this hwgroup (for now) */ 842 goto plug_device; 843 } 844 845 if (drive != orig_drive) 846 goto plug_device; 847again: 848 hwif = drive->hwif; 849 850 if (hwif != hwgroup->hwif) { 851 /* 852 * set nIEN for previous hwif, drives in the 853 * quirk_list may not like intr setups/cleanups 854 */ 855 if (drive->quirk_list == 0) 856 hwif->tp_ops->set_irq(hwif, 0); 857 } 858 hwgroup->hwif = hwif; 859 hwgroup->drive = drive; 860 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED); 861 drive->service_start = jiffies; 862 863 /* 864 * we know that the queue isn't empty, but this can happen 865 * if the q->prep_rq_fn() decides to kill a request 866 */ 867 rq = elv_next_request(drive->queue); 868 if (!rq) { 869 hwgroup->busy = 0; 870 break; 871 } 872 873 /* 874 * Sanity: don't accept a request that isn't a PM request 875 * if we are currently power managed. This is very important as 876 * blk_stop_queue() doesn't prevent the elv_next_request() 877 * above to return us whatever is in the queue. Since we call 878 * ide_do_request() ourselves, we end up taking requests while 879 * the queue is blocked... 880 * 881 * We let requests forced at head of queue with ide-preempt 882 * though. I hope that doesn't happen too much, hopefully not 883 * unless the subdriver triggers such a thing in its own PM 884 * state machine. 885 * 886 * We count how many times we loop here to make sure we service 887 * all drives in the hwgroup without looping for ever 888 */ 889 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) && 890 blk_pm_request(rq) == 0 && 891 (rq->cmd_flags & REQ_PREEMPT) == 0) { 892 drive = drive->next ? drive->next : hwgroup->drive; 893 if (loops++ < 4 && !blk_queue_plugged(drive->queue)) 894 goto again; 895 /* We clear busy, there should be no pending ATA command at this point. */ 896 hwgroup->busy = 0; 897 goto plug_device; 898 } 899 900 hwgroup->rq = rq; 901 902 spin_unlock_irq(&hwgroup->lock); 903 startstop = start_request(drive, rq); 904 spin_lock_irq(&hwgroup->lock); 905 906 if (startstop == ide_stopped) { 907 hwgroup->busy = 0; 908 if (!elv_queue_empty(orig_drive->queue)) 909 blk_plug_device(orig_drive->queue); 910 } 911 } 912 return; 913 914plug_device: 915 if (!elv_queue_empty(orig_drive->queue)) 916 blk_plug_device(orig_drive->queue); 917} 918 919/* 920 * un-busy the hwgroup etc, and clear any pending DMA status. we want to 921 * retry the current request in pio mode instead of risking tossing it 922 * all away 923 */ 924static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error) 925{ 926 ide_hwif_t *hwif = HWIF(drive); 927 struct request *rq; 928 ide_startstop_t ret = ide_stopped; 929 930 /* 931 * end current dma transaction 932 */ 933 934 if (error < 0) { 935 printk(KERN_WARNING "%s: DMA timeout error\n", drive->name); 936 (void)hwif->dma_ops->dma_end(drive); 937 ret = ide_error(drive, "dma timeout error", 938 hwif->tp_ops->read_status(hwif)); 939 } else { 940 printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name); 941 hwif->dma_ops->dma_timeout(drive); 942 } 943 944 /* 945 * disable dma for now, but remember that we did so because of 946 * a timeout -- we'll reenable after we finish this next request 947 * (or rather the first chunk of it) in pio. 948 */ 949 drive->dev_flags |= IDE_DFLAG_DMA_PIO_RETRY; 950 drive->retry_pio++; 951 ide_dma_off_quietly(drive); 952 953 /* 954 * un-busy drive etc (hwgroup->busy is cleared on return) and 955 * make sure request is sane 956 */ 957 rq = HWGROUP(drive)->rq; 958 959 if (!rq) 960 goto out; 961 962 HWGROUP(drive)->rq = NULL; 963 964 rq->errors = 0; 965 966 if (!rq->bio) 967 goto out; 968 969 rq->sector = rq->bio->bi_sector; 970 rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9; 971 rq->hard_cur_sectors = rq->current_nr_sectors; 972 rq->buffer = bio_data(rq->bio); 973out: 974 return ret; 975} 976 977/** 978 * ide_timer_expiry - handle lack of an IDE interrupt 979 * @data: timer callback magic (hwgroup) 980 * 981 * An IDE command has timed out before the expected drive return 982 * occurred. At this point we attempt to clean up the current 983 * mess. If the current handler includes an expiry handler then 984 * we invoke the expiry handler, and providing it is happy the 985 * work is done. If that fails we apply generic recovery rules 986 * invoking the handler and checking the drive DMA status. We 987 * have an excessively incestuous relationship with the DMA 988 * logic that wants cleaning up. 989 */ 990 991void ide_timer_expiry (unsigned long data) 992{ 993 ide_hwgroup_t *hwgroup = (ide_hwgroup_t *) data; 994 ide_handler_t *handler; 995 ide_expiry_t *expiry; 996 unsigned long flags; 997 unsigned long wait = -1; 998 999 spin_lock_irqsave(&hwgroup->lock, flags); 1000 1001 if (((handler = hwgroup->handler) == NULL) || 1002 (hwgroup->req_gen != hwgroup->req_gen_timer)) { 1003 /* 1004 * Either a marginal timeout occurred 1005 * (got the interrupt just as timer expired), 1006 * or we were "sleeping" to give other devices a chance. 1007 * Either way, we don't really want to complain about anything. 1008 */ 1009 if (hwgroup->sleeping) { 1010 hwgroup->sleeping = 0; 1011 hwgroup->busy = 0; 1012 } 1013 } else { 1014 ide_drive_t *drive = hwgroup->drive; 1015 if (!drive) { 1016 printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n"); 1017 hwgroup->handler = NULL; 1018 } else { 1019 ide_hwif_t *hwif; 1020 ide_startstop_t startstop = ide_stopped; 1021 if (!hwgroup->busy) { 1022 hwgroup->busy = 1; /* paranoia */ 1023 printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name); 1024 } 1025 if ((expiry = hwgroup->expiry) != NULL) { 1026 /* continue */ 1027 if ((wait = expiry(drive)) > 0) { 1028 /* reset timer */ 1029 hwgroup->timer.expires = jiffies + wait; 1030 hwgroup->req_gen_timer = hwgroup->req_gen; 1031 add_timer(&hwgroup->timer); 1032 spin_unlock_irqrestore(&hwgroup->lock, flags); 1033 return; 1034 } 1035 } 1036 hwgroup->handler = NULL; 1037 /* 1038 * We need to simulate a real interrupt when invoking 1039 * the handler() function, which means we need to 1040 * globally mask the specific IRQ: 1041 */ 1042 spin_unlock(&hwgroup->lock); 1043 hwif = HWIF(drive); 1044 /* disable_irq_nosync ?? */ 1045 disable_irq(hwif->irq); 1046 /* local CPU only, 1047 * as if we were handling an interrupt */ 1048 local_irq_disable(); 1049 if (hwgroup->polling) { 1050 startstop = handler(drive); 1051 } else if (drive_is_ready(drive)) { 1052 if (drive->waiting_for_dma) 1053 hwif->dma_ops->dma_lost_irq(drive); 1054 (void)ide_ack_intr(hwif); 1055 printk(KERN_WARNING "%s: lost interrupt\n", drive->name); 1056 startstop = handler(drive); 1057 } else { 1058 if (drive->waiting_for_dma) { 1059 startstop = ide_dma_timeout_retry(drive, wait); 1060 } else 1061 startstop = 1062 ide_error(drive, "irq timeout", 1063 hwif->tp_ops->read_status(hwif)); 1064 } 1065 drive->service_time = jiffies - drive->service_start; 1066 spin_lock_irq(&hwgroup->lock); 1067 enable_irq(hwif->irq); 1068 if (startstop == ide_stopped) { 1069 hwgroup->busy = 0; 1070 if (!elv_queue_empty(drive->queue)) 1071 blk_plug_device(drive->queue); 1072 } 1073 } 1074 } 1075 spin_unlock_irqrestore(&hwgroup->lock, flags); 1076} 1077 1078/** 1079 * unexpected_intr - handle an unexpected IDE interrupt 1080 * @irq: interrupt line 1081 * @hwgroup: hwgroup being processed 1082 * 1083 * There's nothing really useful we can do with an unexpected interrupt, 1084 * other than reading the status register (to clear it), and logging it. 1085 * There should be no way that an irq can happen before we're ready for it, 1086 * so we needn't worry much about losing an "important" interrupt here. 1087 * 1088 * On laptops (and "green" PCs), an unexpected interrupt occurs whenever 1089 * the drive enters "idle", "standby", or "sleep" mode, so if the status 1090 * looks "good", we just ignore the interrupt completely. 1091 * 1092 * This routine assumes __cli() is in effect when called. 1093 * 1094 * If an unexpected interrupt happens on irq15 while we are handling irq14 1095 * and if the two interfaces are "serialized" (CMD640), then it looks like 1096 * we could screw up by interfering with a new request being set up for 1097 * irq15. 1098 * 1099 * In reality, this is a non-issue. The new command is not sent unless 1100 * the drive is ready to accept one, in which case we know the drive is 1101 * not trying to interrupt us. And ide_set_handler() is always invoked 1102 * before completing the issuance of any new drive command, so we will not 1103 * be accidentally invoked as a result of any valid command completion 1104 * interrupt. 1105 * 1106 * Note that we must walk the entire hwgroup here. We know which hwif 1107 * is doing the current command, but we don't know which hwif burped 1108 * mysteriously. 1109 */ 1110 1111static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup) 1112{ 1113 u8 stat; 1114 ide_hwif_t *hwif = hwgroup->hwif; 1115 1116 /* 1117 * handle the unexpected interrupt 1118 */ 1119 do { 1120 if (hwif->irq == irq) { 1121 stat = hwif->tp_ops->read_status(hwif); 1122 1123 if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) { 1124 /* Try to not flood the console with msgs */ 1125 static unsigned long last_msgtime, count; 1126 ++count; 1127 if (time_after(jiffies, last_msgtime + HZ)) { 1128 last_msgtime = jiffies; 1129 printk(KERN_ERR "%s%s: unexpected interrupt, " 1130 "status=0x%02x, count=%ld\n", 1131 hwif->name, 1132 (hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count); 1133 } 1134 } 1135 } 1136 } while ((hwif = hwif->next) != hwgroup->hwif); 1137} 1138 1139/** 1140 * ide_intr - default IDE interrupt handler 1141 * @irq: interrupt number 1142 * @dev_id: hwif group 1143 * @regs: unused weirdness from the kernel irq layer 1144 * 1145 * This is the default IRQ handler for the IDE layer. You should 1146 * not need to override it. If you do be aware it is subtle in 1147 * places 1148 * 1149 * hwgroup->hwif is the interface in the group currently performing 1150 * a command. hwgroup->drive is the drive and hwgroup->handler is 1151 * the IRQ handler to call. As we issue a command the handlers 1152 * step through multiple states, reassigning the handler to the 1153 * next step in the process. Unlike a smart SCSI controller IDE 1154 * expects the main processor to sequence the various transfer 1155 * stages. We also manage a poll timer to catch up with most 1156 * timeout situations. There are still a few where the handlers 1157 * don't ever decide to give up. 1158 * 1159 * The handler eventually returns ide_stopped to indicate the 1160 * request completed. At this point we issue the next request 1161 * on the hwgroup and the process begins again. 1162 */ 1163 1164irqreturn_t ide_intr (int irq, void *dev_id) 1165{ 1166 unsigned long flags; 1167 ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id; 1168 ide_hwif_t *hwif = hwgroup->hwif; 1169 ide_drive_t *drive; 1170 ide_handler_t *handler; 1171 ide_startstop_t startstop; 1172 irqreturn_t irq_ret = IRQ_NONE; 1173 1174 spin_lock_irqsave(&hwgroup->lock, flags); 1175 1176 if (!ide_ack_intr(hwif)) 1177 goto out; 1178 1179 if ((handler = hwgroup->handler) == NULL || hwgroup->polling) { 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->chipset != ide_pci) 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->tp_ops->read_status(hwif); 1211#endif /* CONFIG_BLK_DEV_IDEPCI */ 1212 } 1213 goto out; 1214 } 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 goto out_handled; 1225 } 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 goto out; 1236 1237 if (!hwgroup->busy) { 1238 hwgroup->busy = 1; /* paranoia */ 1239 printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name); 1240 } 1241 hwgroup->handler = NULL; 1242 hwgroup->req_gen++; 1243 del_timer(&hwgroup->timer); 1244 spin_unlock(&hwgroup->lock); 1245 1246 if (hwif->port_ops && hwif->port_ops->clear_irq) 1247 hwif->port_ops->clear_irq(drive); 1248 1249 if (drive->dev_flags & IDE_DFLAG_UNMASK) 1250 local_irq_enable_in_hardirq(); 1251 1252 /* service this interrupt, may set handler for next interrupt */ 1253 startstop = handler(drive); 1254 1255 spin_lock_irq(&hwgroup->lock); 1256 /* 1257 * Note that handler() may have set things up for another 1258 * interrupt to occur soon, but it cannot happen until 1259 * we exit from this routine, because it will be the 1260 * same irq as is currently being serviced here, and Linux 1261 * won't allow another of the same (on any CPU) until we return. 1262 */ 1263 drive->service_time = jiffies - drive->service_start; 1264 if (startstop == ide_stopped) { 1265 if (hwgroup->handler == NULL) { /* paranoia */ 1266 hwgroup->busy = 0; 1267 if (!elv_queue_empty(drive->queue)) 1268 blk_plug_device(drive->queue); 1269 } else 1270 printk(KERN_ERR "%s: %s: huh? expected NULL handler " 1271 "on exit\n", __func__, drive->name); 1272 } 1273out_handled: 1274 irq_ret = IRQ_HANDLED; 1275out: 1276 spin_unlock_irqrestore(&hwgroup->lock, flags); 1277 return irq_ret; 1278} 1279 1280/** 1281 * ide_do_drive_cmd - issue IDE special command 1282 * @drive: device to issue command 1283 * @rq: request to issue 1284 * 1285 * This function issues a special IDE device request 1286 * onto the request queue. 1287 * 1288 * the rq is queued at the head of the request queue, displacing 1289 * the currently-being-processed request and this function 1290 * returns immediately without waiting for the new rq to be 1291 * completed. This is VERY DANGEROUS, and is intended for 1292 * careful use by the ATAPI tape/cdrom driver code. 1293 */ 1294 1295void ide_do_drive_cmd(ide_drive_t *drive, struct request *rq) 1296{ 1297 ide_hwgroup_t *hwgroup = drive->hwif->hwgroup; 1298 struct request_queue *q = drive->queue; 1299 unsigned long flags; 1300 1301 hwgroup->rq = NULL; 1302 1303 spin_lock_irqsave(q->queue_lock, flags); 1304 __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); 1305 blk_start_queueing(q); 1306 spin_unlock_irqrestore(q->queue_lock, flags); 1307} 1308EXPORT_SYMBOL(ide_do_drive_cmd); 1309 1310void ide_pktcmd_tf_load(ide_drive_t *drive, u32 tf_flags, u16 bcount, u8 dma) 1311{ 1312 ide_hwif_t *hwif = drive->hwif; 1313 ide_task_t task; 1314 1315 memset(&task, 0, sizeof(task)); 1316 task.tf_flags = IDE_TFLAG_OUT_LBAH | IDE_TFLAG_OUT_LBAM | 1317 IDE_TFLAG_OUT_FEATURE | tf_flags; 1318 task.tf.feature = dma; /* Use PIO/DMA */ 1319 task.tf.lbam = bcount & 0xff; 1320 task.tf.lbah = (bcount >> 8) & 0xff; 1321 1322 ide_tf_dump(drive->name, &task.tf); 1323 hwif->tp_ops->set_irq(hwif, 1); 1324 SELECT_MASK(drive, 0); 1325 hwif->tp_ops->tf_load(drive, &task); 1326} 1327 1328EXPORT_SYMBOL_GPL(ide_pktcmd_tf_load); 1329 1330void ide_pad_transfer(ide_drive_t *drive, int write, int len) 1331{ 1332 ide_hwif_t *hwif = drive->hwif; 1333 u8 buf[4] = { 0 }; 1334 1335 while (len > 0) { 1336 if (write) 1337 hwif->tp_ops->output_data(drive, NULL, buf, min(4, len)); 1338 else 1339 hwif->tp_ops->input_data(drive, NULL, buf, min(4, len)); 1340 len -= 4; 1341 } 1342} 1343EXPORT_SYMBOL_GPL(ide_pad_transfer); 1344