ide: Fix code dealing with sleeping devices in do_ide_request()
[deliverable/linux.git] / drivers / ide / ide-io.c
1 /*
2 * IDE I/O functions
3 *
4 * Basic PIO and command management functionality.
5 *
6 * This code was split off from ide.c. See ide.c for history and original
7 * copyrights.
8 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2, or (at your option) any
12 * later version.
13 *
14 * This program is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * General Public License for more details.
18 *
19 * For the avoidance of doubt the "preferred form" of this code is one which
20 * is in an open non patent encumbered format. Where cryptographic key signing
21 * forms part of the process of creating an executable the information
22 * including keys needed to generate an equivalently functional executable
23 * are deemed to be part of the source code.
24 */
25
26
27 #include <linux/module.h>
28 #include <linux/types.h>
29 #include <linux/string.h>
30 #include <linux/kernel.h>
31 #include <linux/timer.h>
32 #include <linux/mm.h>
33 #include <linux/interrupt.h>
34 #include <linux/major.h>
35 #include <linux/errno.h>
36 #include <linux/genhd.h>
37 #include <linux/blkpg.h>
38 #include <linux/slab.h>
39 #include <linux/init.h>
40 #include <linux/pci.h>
41 #include <linux/delay.h>
42 #include <linux/ide.h>
43 #include <linux/completion.h>
44 #include <linux/reboot.h>
45 #include <linux/cdrom.h>
46 #include <linux/seq_file.h>
47 #include <linux/device.h>
48 #include <linux/kmod.h>
49 #include <linux/scatterlist.h>
50 #include <linux/bitops.h>
51
52 #include <asm/byteorder.h>
53 #include <asm/irq.h>
54 #include <asm/uaccess.h>
55 #include <asm/io.h>
56
57 int ide_end_rq(ide_drive_t *drive, struct request *rq, int error,
58 unsigned int nr_bytes)
59 {
60 /*
61 * decide whether to reenable DMA -- 3 is a random magic for now,
62 * if we DMA timeout more than 3 times, just stay in PIO
63 */
64 if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
65 drive->retry_pio <= 3) {
66 drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
67 ide_dma_on(drive);
68 }
69
70 return blk_end_request(rq, error, nr_bytes);
71 }
72 EXPORT_SYMBOL_GPL(ide_end_rq);
73
74 void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err)
75 {
76 struct ide_taskfile *tf = &cmd->tf;
77 struct request *rq = cmd->rq;
78 u8 tf_cmd = tf->command;
79
80 tf->error = err;
81 tf->status = stat;
82
83 drive->hwif->tp_ops->tf_read(drive, cmd);
84
85 if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) &&
86 tf_cmd == ATA_CMD_IDLEIMMEDIATE) {
87 if (tf->lbal != 0xc4) {
88 printk(KERN_ERR "%s: head unload failed!\n",
89 drive->name);
90 ide_tf_dump(drive->name, tf);
91 } else
92 drive->dev_flags |= IDE_DFLAG_PARKED;
93 }
94
95 if (rq && rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
96 memcpy(rq->special, cmd, sizeof(*cmd));
97
98 if (cmd->tf_flags & IDE_TFLAG_DYN)
99 kfree(cmd);
100 }
101
102 /* obsolete, blk_rq_bytes() should be used instead */
103 unsigned int ide_rq_bytes(struct request *rq)
104 {
105 if (blk_pc_request(rq))
106 return rq->data_len;
107 else
108 return rq->hard_cur_sectors << 9;
109 }
110 EXPORT_SYMBOL_GPL(ide_rq_bytes);
111
112 int ide_complete_rq(ide_drive_t *drive, int error, unsigned int nr_bytes)
113 {
114 ide_hwif_t *hwif = drive->hwif;
115 struct request *rq = hwif->rq;
116 int rc;
117
118 /*
119 * if failfast is set on a request, override number of sectors
120 * and complete the whole request right now
121 */
122 if (blk_noretry_request(rq) && error <= 0)
123 nr_bytes = rq->hard_nr_sectors << 9;
124
125 rc = ide_end_rq(drive, rq, error, nr_bytes);
126 if (rc == 0)
127 hwif->rq = NULL;
128
129 return rc;
130 }
131 EXPORT_SYMBOL(ide_complete_rq);
132
133 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
134 {
135 u8 drv_req = blk_special_request(rq) && rq->rq_disk;
136 u8 media = drive->media;
137
138 drive->failed_pc = NULL;
139
140 if ((media == ide_floppy || media == ide_tape) && drv_req) {
141 rq->errors = 0;
142 ide_complete_rq(drive, 0, blk_rq_bytes(rq));
143 } else {
144 if (media == ide_tape)
145 rq->errors = IDE_DRV_ERROR_GENERAL;
146 else if (blk_fs_request(rq) == 0 && rq->errors == 0)
147 rq->errors = -EIO;
148 ide_complete_rq(drive, -EIO, ide_rq_bytes(rq));
149 }
150 }
151
152 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
153 {
154 tf->nsect = drive->sect;
155 tf->lbal = drive->sect;
156 tf->lbam = drive->cyl;
157 tf->lbah = drive->cyl >> 8;
158 tf->device = (drive->head - 1) | drive->select;
159 tf->command = ATA_CMD_INIT_DEV_PARAMS;
160 }
161
162 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
163 {
164 tf->nsect = drive->sect;
165 tf->command = ATA_CMD_RESTORE;
166 }
167
168 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
169 {
170 tf->nsect = drive->mult_req;
171 tf->command = ATA_CMD_SET_MULTI;
172 }
173
174 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
175 {
176 special_t *s = &drive->special;
177 struct ide_cmd cmd;
178
179 memset(&cmd, 0, sizeof(cmd));
180 cmd.protocol = ATA_PROT_NODATA;
181
182 if (s->b.set_geometry) {
183 s->b.set_geometry = 0;
184 ide_tf_set_specify_cmd(drive, &cmd.tf);
185 } else if (s->b.recalibrate) {
186 s->b.recalibrate = 0;
187 ide_tf_set_restore_cmd(drive, &cmd.tf);
188 } else if (s->b.set_multmode) {
189 s->b.set_multmode = 0;
190 ide_tf_set_setmult_cmd(drive, &cmd.tf);
191 } else if (s->all) {
192 int special = s->all;
193 s->all = 0;
194 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
195 return ide_stopped;
196 }
197
198 cmd.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE |
199 IDE_TFLAG_CUSTOM_HANDLER;
200
201 do_rw_taskfile(drive, &cmd);
202
203 return ide_started;
204 }
205
206 /**
207 * do_special - issue some special commands
208 * @drive: drive the command is for
209 *
210 * do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
211 * ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
212 *
213 * It used to do much more, but has been scaled back.
214 */
215
216 static ide_startstop_t do_special (ide_drive_t *drive)
217 {
218 special_t *s = &drive->special;
219
220 #ifdef DEBUG
221 printk("%s: do_special: 0x%02x\n", drive->name, s->all);
222 #endif
223 if (drive->media == ide_disk)
224 return ide_disk_special(drive);
225
226 s->all = 0;
227 drive->mult_req = 0;
228 return ide_stopped;
229 }
230
231 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
232 {
233 ide_hwif_t *hwif = drive->hwif;
234 struct scatterlist *sg = hwif->sg_table;
235 struct request *rq = cmd->rq;
236
237 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
238 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
239 cmd->sg_nents = 1;
240 } else if (!rq->bio) {
241 sg_init_one(sg, rq->data, rq->data_len);
242 cmd->sg_nents = 1;
243 } else
244 cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
245 }
246 EXPORT_SYMBOL_GPL(ide_map_sg);
247
248 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
249 {
250 cmd->nbytes = cmd->nleft = nr_bytes;
251 cmd->cursg_ofs = 0;
252 cmd->cursg = NULL;
253 }
254 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
255
256 /**
257 * execute_drive_command - issue special drive command
258 * @drive: the drive to issue the command on
259 * @rq: the request structure holding the command
260 *
261 * execute_drive_cmd() issues a special drive command, usually
262 * initiated by ioctl() from the external hdparm program. The
263 * command can be a drive command, drive task or taskfile
264 * operation. Weirdly you can call it with NULL to wait for
265 * all commands to finish. Don't do this as that is due to change
266 */
267
268 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
269 struct request *rq)
270 {
271 struct ide_cmd *cmd = rq->special;
272
273 if (cmd) {
274 if (cmd->protocol == ATA_PROT_PIO) {
275 ide_init_sg_cmd(cmd, rq->nr_sectors << 9);
276 ide_map_sg(drive, cmd);
277 }
278
279 return do_rw_taskfile(drive, cmd);
280 }
281
282 /*
283 * NULL is actually a valid way of waiting for
284 * all current requests to be flushed from the queue.
285 */
286 #ifdef DEBUG
287 printk("%s: DRIVE_CMD (null)\n", drive->name);
288 #endif
289 rq->errors = 0;
290 ide_complete_rq(drive, 0, blk_rq_bytes(rq));
291
292 return ide_stopped;
293 }
294
295 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
296 {
297 u8 cmd = rq->cmd[0];
298
299 switch (cmd) {
300 case REQ_PARK_HEADS:
301 case REQ_UNPARK_HEADS:
302 return ide_do_park_unpark(drive, rq);
303 case REQ_DEVSET_EXEC:
304 return ide_do_devset(drive, rq);
305 case REQ_DRIVE_RESET:
306 return ide_do_reset(drive);
307 default:
308 BUG();
309 }
310 }
311
312 /**
313 * start_request - start of I/O and command issuing for IDE
314 *
315 * start_request() initiates handling of a new I/O request. It
316 * accepts commands and I/O (read/write) requests.
317 *
318 * FIXME: this function needs a rename
319 */
320
321 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
322 {
323 ide_startstop_t startstop;
324
325 BUG_ON(!blk_rq_started(rq));
326
327 #ifdef DEBUG
328 printk("%s: start_request: current=0x%08lx\n",
329 drive->hwif->name, (unsigned long) rq);
330 #endif
331
332 /* bail early if we've exceeded max_failures */
333 if (drive->max_failures && (drive->failures > drive->max_failures)) {
334 rq->cmd_flags |= REQ_FAILED;
335 goto kill_rq;
336 }
337
338 if (blk_pm_request(rq))
339 ide_check_pm_state(drive, rq);
340
341 SELECT_DRIVE(drive);
342 if (ide_wait_stat(&startstop, drive, drive->ready_stat,
343 ATA_BUSY | ATA_DRQ, WAIT_READY)) {
344 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
345 return startstop;
346 }
347 if (!drive->special.all) {
348 struct ide_driver *drv;
349
350 /*
351 * We reset the drive so we need to issue a SETFEATURES.
352 * Do it _after_ do_special() restored device parameters.
353 */
354 if (drive->current_speed == 0xff)
355 ide_config_drive_speed(drive, drive->desired_speed);
356
357 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
358 return execute_drive_cmd(drive, rq);
359 else if (blk_pm_request(rq)) {
360 struct request_pm_state *pm = rq->data;
361 #ifdef DEBUG_PM
362 printk("%s: start_power_step(step: %d)\n",
363 drive->name, pm->pm_step);
364 #endif
365 startstop = ide_start_power_step(drive, rq);
366 if (startstop == ide_stopped &&
367 pm->pm_step == IDE_PM_COMPLETED)
368 ide_complete_pm_rq(drive, rq);
369 return startstop;
370 } else if (!rq->rq_disk && blk_special_request(rq))
371 /*
372 * TODO: Once all ULDs have been modified to
373 * check for specific op codes rather than
374 * blindly accepting any special request, the
375 * check for ->rq_disk above may be replaced
376 * by a more suitable mechanism or even
377 * dropped entirely.
378 */
379 return ide_special_rq(drive, rq);
380
381 drv = *(struct ide_driver **)rq->rq_disk->private_data;
382
383 return drv->do_request(drive, rq, rq->sector);
384 }
385 return do_special(drive);
386 kill_rq:
387 ide_kill_rq(drive, rq);
388 return ide_stopped;
389 }
390
391 /**
392 * ide_stall_queue - pause an IDE device
393 * @drive: drive to stall
394 * @timeout: time to stall for (jiffies)
395 *
396 * ide_stall_queue() can be used by a drive to give excess bandwidth back
397 * to the port by sleeping for timeout jiffies.
398 */
399
400 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
401 {
402 if (timeout > WAIT_WORSTCASE)
403 timeout = WAIT_WORSTCASE;
404 drive->sleep = timeout + jiffies;
405 drive->dev_flags |= IDE_DFLAG_SLEEPING;
406 }
407 EXPORT_SYMBOL(ide_stall_queue);
408
409 static inline int ide_lock_port(ide_hwif_t *hwif)
410 {
411 if (hwif->busy)
412 return 1;
413
414 hwif->busy = 1;
415
416 return 0;
417 }
418
419 static inline void ide_unlock_port(ide_hwif_t *hwif)
420 {
421 hwif->busy = 0;
422 }
423
424 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
425 {
426 int rc = 0;
427
428 if (host->host_flags & IDE_HFLAG_SERIALIZE) {
429 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
430 if (rc == 0) {
431 if (host->get_lock)
432 host->get_lock(ide_intr, hwif);
433 }
434 }
435 return rc;
436 }
437
438 static inline void ide_unlock_host(struct ide_host *host)
439 {
440 if (host->host_flags & IDE_HFLAG_SERIALIZE) {
441 if (host->release_lock)
442 host->release_lock();
443 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
444 }
445 }
446
447 /*
448 * Issue a new request to a device.
449 */
450 void do_ide_request(struct request_queue *q)
451 {
452 ide_drive_t *drive = q->queuedata;
453 ide_hwif_t *hwif = drive->hwif;
454 struct ide_host *host = hwif->host;
455 struct request *rq = NULL;
456 ide_startstop_t startstop;
457
458 /*
459 * drive is doing pre-flush, ordered write, post-flush sequence. even
460 * though that is 3 requests, it must be seen as a single transaction.
461 * we must not preempt this drive until that is complete
462 */
463 if (blk_queue_flushing(q))
464 /*
465 * small race where queue could get replugged during
466 * the 3-request flush cycle, just yank the plug since
467 * we want it to finish asap
468 */
469 blk_remove_plug(q);
470
471 spin_unlock_irq(q->queue_lock);
472
473 if (ide_lock_host(host, hwif))
474 goto plug_device_2;
475
476 spin_lock_irq(&hwif->lock);
477
478 if (!ide_lock_port(hwif)) {
479 ide_hwif_t *prev_port;
480 repeat:
481 prev_port = hwif->host->cur_port;
482 hwif->rq = NULL;
483
484 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
485 time_after(drive->sleep, jiffies)) {
486 ide_unlock_port(hwif);
487 goto plug_device;
488 }
489
490 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
491 hwif != prev_port) {
492 /*
493 * set nIEN for previous port, drives in the
494 * quirk_list may not like intr setups/cleanups
495 */
496 if (prev_port && prev_port->cur_dev->quirk_list == 0)
497 prev_port->tp_ops->set_irq(prev_port, 0);
498
499 hwif->host->cur_port = hwif;
500 }
501 hwif->cur_dev = drive;
502 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
503
504 spin_unlock_irq(&hwif->lock);
505 spin_lock_irq(q->queue_lock);
506 /*
507 * we know that the queue isn't empty, but this can happen
508 * if the q->prep_rq_fn() decides to kill a request
509 */
510 rq = elv_next_request(drive->queue);
511 spin_unlock_irq(q->queue_lock);
512 spin_lock_irq(&hwif->lock);
513
514 if (!rq) {
515 ide_unlock_port(hwif);
516 goto out;
517 }
518
519 /*
520 * Sanity: don't accept a request that isn't a PM request
521 * if we are currently power managed. This is very important as
522 * blk_stop_queue() doesn't prevent the elv_next_request()
523 * above to return us whatever is in the queue. Since we call
524 * ide_do_request() ourselves, we end up taking requests while
525 * the queue is blocked...
526 *
527 * We let requests forced at head of queue with ide-preempt
528 * though. I hope that doesn't happen too much, hopefully not
529 * unless the subdriver triggers such a thing in its own PM
530 * state machine.
531 */
532 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
533 blk_pm_request(rq) == 0 &&
534 (rq->cmd_flags & REQ_PREEMPT) == 0) {
535 /* there should be no pending command at this point */
536 ide_unlock_port(hwif);
537 goto plug_device;
538 }
539
540 hwif->rq = rq;
541
542 spin_unlock_irq(&hwif->lock);
543 startstop = start_request(drive, rq);
544 spin_lock_irq(&hwif->lock);
545
546 if (startstop == ide_stopped)
547 goto repeat;
548 } else
549 goto plug_device;
550 out:
551 spin_unlock_irq(&hwif->lock);
552 if (rq == NULL)
553 ide_unlock_host(host);
554 spin_lock_irq(q->queue_lock);
555 return;
556
557 plug_device:
558 spin_unlock_irq(&hwif->lock);
559 ide_unlock_host(host);
560 plug_device_2:
561 spin_lock_irq(q->queue_lock);
562
563 if (!elv_queue_empty(q))
564 blk_plug_device(q);
565 }
566
567 static void ide_plug_device(ide_drive_t *drive)
568 {
569 struct request_queue *q = drive->queue;
570 unsigned long flags;
571
572 spin_lock_irqsave(q->queue_lock, flags);
573 if (!elv_queue_empty(q))
574 blk_plug_device(q);
575 spin_unlock_irqrestore(q->queue_lock, flags);
576 }
577
578 static int drive_is_ready(ide_drive_t *drive)
579 {
580 ide_hwif_t *hwif = drive->hwif;
581 u8 stat = 0;
582
583 if (drive->waiting_for_dma)
584 return hwif->dma_ops->dma_test_irq(drive);
585
586 if (hwif->io_ports.ctl_addr &&
587 (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
588 stat = hwif->tp_ops->read_altstatus(hwif);
589 else
590 /* Note: this may clear a pending IRQ!! */
591 stat = hwif->tp_ops->read_status(hwif);
592
593 if (stat & ATA_BUSY)
594 /* drive busy: definitely not interrupting */
595 return 0;
596
597 /* drive ready: *might* be interrupting */
598 return 1;
599 }
600
601 /**
602 * ide_timer_expiry - handle lack of an IDE interrupt
603 * @data: timer callback magic (hwif)
604 *
605 * An IDE command has timed out before the expected drive return
606 * occurred. At this point we attempt to clean up the current
607 * mess. If the current handler includes an expiry handler then
608 * we invoke the expiry handler, and providing it is happy the
609 * work is done. If that fails we apply generic recovery rules
610 * invoking the handler and checking the drive DMA status. We
611 * have an excessively incestuous relationship with the DMA
612 * logic that wants cleaning up.
613 */
614
615 void ide_timer_expiry (unsigned long data)
616 {
617 ide_hwif_t *hwif = (ide_hwif_t *)data;
618 ide_drive_t *uninitialized_var(drive);
619 ide_handler_t *handler;
620 unsigned long flags;
621 int wait = -1;
622 int plug_device = 0;
623
624 spin_lock_irqsave(&hwif->lock, flags);
625
626 handler = hwif->handler;
627
628 if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
629 /*
630 * Either a marginal timeout occurred
631 * (got the interrupt just as timer expired),
632 * or we were "sleeping" to give other devices a chance.
633 * Either way, we don't really want to complain about anything.
634 */
635 } else {
636 ide_expiry_t *expiry = hwif->expiry;
637 ide_startstop_t startstop = ide_stopped;
638
639 drive = hwif->cur_dev;
640
641 if (expiry) {
642 wait = expiry(drive);
643 if (wait > 0) { /* continue */
644 /* reset timer */
645 hwif->timer.expires = jiffies + wait;
646 hwif->req_gen_timer = hwif->req_gen;
647 add_timer(&hwif->timer);
648 spin_unlock_irqrestore(&hwif->lock, flags);
649 return;
650 }
651 }
652 hwif->handler = NULL;
653 hwif->expiry = NULL;
654 /*
655 * We need to simulate a real interrupt when invoking
656 * the handler() function, which means we need to
657 * globally mask the specific IRQ:
658 */
659 spin_unlock(&hwif->lock);
660 /* disable_irq_nosync ?? */
661 disable_irq(hwif->irq);
662 /* local CPU only, as if we were handling an interrupt */
663 local_irq_disable();
664 if (hwif->polling) {
665 startstop = handler(drive);
666 } else if (drive_is_ready(drive)) {
667 if (drive->waiting_for_dma)
668 hwif->dma_ops->dma_lost_irq(drive);
669 if (hwif->ack_intr)
670 hwif->ack_intr(hwif);
671 printk(KERN_WARNING "%s: lost interrupt\n",
672 drive->name);
673 startstop = handler(drive);
674 } else {
675 if (drive->waiting_for_dma)
676 startstop = ide_dma_timeout_retry(drive, wait);
677 else
678 startstop = ide_error(drive, "irq timeout",
679 hwif->tp_ops->read_status(hwif));
680 }
681 spin_lock_irq(&hwif->lock);
682 enable_irq(hwif->irq);
683 if (startstop == ide_stopped) {
684 ide_unlock_port(hwif);
685 plug_device = 1;
686 }
687 }
688 spin_unlock_irqrestore(&hwif->lock, flags);
689
690 if (plug_device) {
691 ide_unlock_host(hwif->host);
692 ide_plug_device(drive);
693 }
694 }
695
696 /**
697 * unexpected_intr - handle an unexpected IDE interrupt
698 * @irq: interrupt line
699 * @hwif: port being processed
700 *
701 * There's nothing really useful we can do with an unexpected interrupt,
702 * other than reading the status register (to clear it), and logging it.
703 * There should be no way that an irq can happen before we're ready for it,
704 * so we needn't worry much about losing an "important" interrupt here.
705 *
706 * On laptops (and "green" PCs), an unexpected interrupt occurs whenever
707 * the drive enters "idle", "standby", or "sleep" mode, so if the status
708 * looks "good", we just ignore the interrupt completely.
709 *
710 * This routine assumes __cli() is in effect when called.
711 *
712 * If an unexpected interrupt happens on irq15 while we are handling irq14
713 * and if the two interfaces are "serialized" (CMD640), then it looks like
714 * we could screw up by interfering with a new request being set up for
715 * irq15.
716 *
717 * In reality, this is a non-issue. The new command is not sent unless
718 * the drive is ready to accept one, in which case we know the drive is
719 * not trying to interrupt us. And ide_set_handler() is always invoked
720 * before completing the issuance of any new drive command, so we will not
721 * be accidentally invoked as a result of any valid command completion
722 * interrupt.
723 */
724
725 static void unexpected_intr(int irq, ide_hwif_t *hwif)
726 {
727 u8 stat = hwif->tp_ops->read_status(hwif);
728
729 if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
730 /* Try to not flood the console with msgs */
731 static unsigned long last_msgtime, count;
732 ++count;
733
734 if (time_after(jiffies, last_msgtime + HZ)) {
735 last_msgtime = jiffies;
736 printk(KERN_ERR "%s: unexpected interrupt, "
737 "status=0x%02x, count=%ld\n",
738 hwif->name, stat, count);
739 }
740 }
741 }
742
743 /**
744 * ide_intr - default IDE interrupt handler
745 * @irq: interrupt number
746 * @dev_id: hwif
747 * @regs: unused weirdness from the kernel irq layer
748 *
749 * This is the default IRQ handler for the IDE layer. You should
750 * not need to override it. If you do be aware it is subtle in
751 * places
752 *
753 * hwif is the interface in the group currently performing
754 * a command. hwif->cur_dev is the drive and hwif->handler is
755 * the IRQ handler to call. As we issue a command the handlers
756 * step through multiple states, reassigning the handler to the
757 * next step in the process. Unlike a smart SCSI controller IDE
758 * expects the main processor to sequence the various transfer
759 * stages. We also manage a poll timer to catch up with most
760 * timeout situations. There are still a few where the handlers
761 * don't ever decide to give up.
762 *
763 * The handler eventually returns ide_stopped to indicate the
764 * request completed. At this point we issue the next request
765 * on the port and the process begins again.
766 */
767
768 irqreturn_t ide_intr (int irq, void *dev_id)
769 {
770 ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
771 struct ide_host *host = hwif->host;
772 ide_drive_t *uninitialized_var(drive);
773 ide_handler_t *handler;
774 unsigned long flags;
775 ide_startstop_t startstop;
776 irqreturn_t irq_ret = IRQ_NONE;
777 int plug_device = 0;
778
779 if (host->host_flags & IDE_HFLAG_SERIALIZE) {
780 if (hwif != host->cur_port)
781 goto out_early;
782 }
783
784 spin_lock_irqsave(&hwif->lock, flags);
785
786 if (hwif->ack_intr && hwif->ack_intr(hwif) == 0)
787 goto out;
788
789 handler = hwif->handler;
790
791 if (handler == NULL || hwif->polling) {
792 /*
793 * Not expecting an interrupt from this drive.
794 * That means this could be:
795 * (1) an interrupt from another PCI device
796 * sharing the same PCI INT# as us.
797 * or (2) a drive just entered sleep or standby mode,
798 * and is interrupting to let us know.
799 * or (3) a spurious interrupt of unknown origin.
800 *
801 * For PCI, we cannot tell the difference,
802 * so in that case we just ignore it and hope it goes away.
803 */
804 if ((host->irq_flags & IRQF_SHARED) == 0) {
805 /*
806 * Probably not a shared PCI interrupt,
807 * so we can safely try to do something about it:
808 */
809 unexpected_intr(irq, hwif);
810 } else {
811 /*
812 * Whack the status register, just in case
813 * we have a leftover pending IRQ.
814 */
815 (void)hwif->tp_ops->read_status(hwif);
816 }
817 goto out;
818 }
819
820 drive = hwif->cur_dev;
821
822 if (!drive_is_ready(drive))
823 /*
824 * This happens regularly when we share a PCI IRQ with
825 * another device. Unfortunately, it can also happen
826 * with some buggy drives that trigger the IRQ before
827 * their status register is up to date. Hopefully we have
828 * enough advance overhead that the latter isn't a problem.
829 */
830 goto out;
831
832 hwif->handler = NULL;
833 hwif->expiry = NULL;
834 hwif->req_gen++;
835 del_timer(&hwif->timer);
836 spin_unlock(&hwif->lock);
837
838 if (hwif->port_ops && hwif->port_ops->clear_irq)
839 hwif->port_ops->clear_irq(drive);
840
841 if (drive->dev_flags & IDE_DFLAG_UNMASK)
842 local_irq_enable_in_hardirq();
843
844 /* service this interrupt, may set handler for next interrupt */
845 startstop = handler(drive);
846
847 spin_lock_irq(&hwif->lock);
848 /*
849 * Note that handler() may have set things up for another
850 * interrupt to occur soon, but it cannot happen until
851 * we exit from this routine, because it will be the
852 * same irq as is currently being serviced here, and Linux
853 * won't allow another of the same (on any CPU) until we return.
854 */
855 if (startstop == ide_stopped) {
856 BUG_ON(hwif->handler);
857 ide_unlock_port(hwif);
858 plug_device = 1;
859 }
860 irq_ret = IRQ_HANDLED;
861 out:
862 spin_unlock_irqrestore(&hwif->lock, flags);
863 out_early:
864 if (plug_device) {
865 ide_unlock_host(hwif->host);
866 ide_plug_device(drive);
867 }
868
869 return irq_ret;
870 }
871 EXPORT_SYMBOL_GPL(ide_intr);
872
873 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
874 {
875 ide_hwif_t *hwif = drive->hwif;
876 u8 buf[4] = { 0 };
877
878 while (len > 0) {
879 if (write)
880 hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
881 else
882 hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
883 len -= 4;
884 }
885 }
886 EXPORT_SYMBOL_GPL(ide_pad_transfer);
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