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 const struct ide_tp_ops *tp_ops = drive->hwif->tp_ops;
77 struct ide_taskfile *tf = &cmd->tf;
78 struct request *rq = cmd->rq;
79 u8 tf_cmd = tf->command;
80
81 tf->error = err;
82 tf->status = stat;
83
84 if (cmd->ftf_flags & IDE_FTFLAG_IN_DATA) {
85 u8 data[2];
86
87 tp_ops->input_data(drive, cmd, data, 2);
88
89 cmd->tf.data = data[0];
90 cmd->hob.data = data[1];
91 }
92
93 ide_tf_readback(drive, cmd);
94
95 if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) &&
96 tf_cmd == ATA_CMD_IDLEIMMEDIATE) {
97 if (tf->lbal != 0xc4) {
98 printk(KERN_ERR "%s: head unload failed!\n",
99 drive->name);
100 ide_tf_dump(drive->name, cmd);
101 } else
102 drive->dev_flags |= IDE_DFLAG_PARKED;
103 }
104
105 if (rq && rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
106 struct ide_cmd *orig_cmd = rq->special;
107
108 if (cmd->tf_flags & IDE_TFLAG_DYN)
109 kfree(orig_cmd);
110 else
111 memcpy(orig_cmd, cmd, sizeof(*cmd));
112 }
113 }
114
115 int ide_complete_rq(ide_drive_t *drive, int error, unsigned int nr_bytes)
116 {
117 ide_hwif_t *hwif = drive->hwif;
118 struct request *rq = hwif->rq;
119 int rc;
120
121 /*
122 * if failfast is set on a request, override number of sectors
123 * and complete the whole request right now
124 */
125 if (blk_noretry_request(rq) && error <= 0)
126 nr_bytes = blk_rq_sectors(rq) << 9;
127
128 rc = ide_end_rq(drive, rq, error, nr_bytes);
129 if (rc == 0)
130 hwif->rq = NULL;
131
132 return rc;
133 }
134 EXPORT_SYMBOL(ide_complete_rq);
135
136 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
137 {
138 u8 drv_req = blk_special_request(rq) && rq->rq_disk;
139 u8 media = drive->media;
140
141 drive->failed_pc = NULL;
142
143 if ((media == ide_floppy || media == ide_tape) && drv_req) {
144 rq->errors = 0;
145 } else {
146 if (media == ide_tape)
147 rq->errors = IDE_DRV_ERROR_GENERAL;
148 else if (blk_fs_request(rq) == 0 && rq->errors == 0)
149 rq->errors = -EIO;
150 }
151
152 ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
153 }
154
155 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
156 {
157 tf->nsect = drive->sect;
158 tf->lbal = drive->sect;
159 tf->lbam = drive->cyl;
160 tf->lbah = drive->cyl >> 8;
161 tf->device = (drive->head - 1) | drive->select;
162 tf->command = ATA_CMD_INIT_DEV_PARAMS;
163 }
164
165 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
166 {
167 tf->nsect = drive->sect;
168 tf->command = ATA_CMD_RESTORE;
169 }
170
171 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
172 {
173 tf->nsect = drive->mult_req;
174 tf->command = ATA_CMD_SET_MULTI;
175 }
176
177 /**
178 * do_special - issue some special commands
179 * @drive: drive the command is for
180 *
181 * do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
182 * ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
183 */
184
185 static ide_startstop_t do_special(ide_drive_t *drive)
186 {
187 struct ide_cmd cmd;
188
189 #ifdef DEBUG
190 printk(KERN_DEBUG "%s: %s: 0x%02x\n", drive->name, __func__,
191 drive->special_flags);
192 #endif
193 if (drive->media != ide_disk) {
194 drive->special_flags = 0;
195 drive->mult_req = 0;
196 return ide_stopped;
197 }
198
199 memset(&cmd, 0, sizeof(cmd));
200 cmd.protocol = ATA_PROT_NODATA;
201
202 if (drive->special_flags & IDE_SFLAG_SET_GEOMETRY) {
203 drive->special_flags &= ~IDE_SFLAG_SET_GEOMETRY;
204 ide_tf_set_specify_cmd(drive, &cmd.tf);
205 } else if (drive->special_flags & IDE_SFLAG_RECALIBRATE) {
206 drive->special_flags &= ~IDE_SFLAG_RECALIBRATE;
207 ide_tf_set_restore_cmd(drive, &cmd.tf);
208 } else if (drive->special_flags & IDE_SFLAG_SET_MULTMODE) {
209 drive->special_flags &= ~IDE_SFLAG_SET_MULTMODE;
210 ide_tf_set_setmult_cmd(drive, &cmd.tf);
211 } else
212 BUG();
213
214 cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
215 cmd.valid.in.tf = IDE_VALID_IN_TF | IDE_VALID_DEVICE;
216 cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER;
217
218 do_rw_taskfile(drive, &cmd);
219
220 return ide_started;
221 }
222
223 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
224 {
225 ide_hwif_t *hwif = drive->hwif;
226 struct scatterlist *sg = hwif->sg_table;
227 struct request *rq = cmd->rq;
228
229 cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
230 }
231 EXPORT_SYMBOL_GPL(ide_map_sg);
232
233 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
234 {
235 cmd->nbytes = cmd->nleft = nr_bytes;
236 cmd->cursg_ofs = 0;
237 cmd->cursg = NULL;
238 }
239 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
240
241 /**
242 * execute_drive_command - issue special drive command
243 * @drive: the drive to issue the command on
244 * @rq: the request structure holding the command
245 *
246 * execute_drive_cmd() issues a special drive command, usually
247 * initiated by ioctl() from the external hdparm program. The
248 * command can be a drive command, drive task or taskfile
249 * operation. Weirdly you can call it with NULL to wait for
250 * all commands to finish. Don't do this as that is due to change
251 */
252
253 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
254 struct request *rq)
255 {
256 struct ide_cmd *cmd = rq->special;
257
258 if (cmd) {
259 if (cmd->protocol == ATA_PROT_PIO) {
260 ide_init_sg_cmd(cmd, blk_rq_sectors(rq) << 9);
261 ide_map_sg(drive, cmd);
262 }
263
264 return do_rw_taskfile(drive, cmd);
265 }
266
267 /*
268 * NULL is actually a valid way of waiting for
269 * all current requests to be flushed from the queue.
270 */
271 #ifdef DEBUG
272 printk("%s: DRIVE_CMD (null)\n", drive->name);
273 #endif
274 rq->errors = 0;
275 ide_complete_rq(drive, 0, blk_rq_bytes(rq));
276
277 return ide_stopped;
278 }
279
280 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
281 {
282 u8 cmd = rq->cmd[0];
283
284 switch (cmd) {
285 case REQ_PARK_HEADS:
286 case REQ_UNPARK_HEADS:
287 return ide_do_park_unpark(drive, rq);
288 case REQ_DEVSET_EXEC:
289 return ide_do_devset(drive, rq);
290 case REQ_DRIVE_RESET:
291 return ide_do_reset(drive);
292 default:
293 BUG();
294 }
295 }
296
297 /**
298 * start_request - start of I/O and command issuing for IDE
299 *
300 * start_request() initiates handling of a new I/O request. It
301 * accepts commands and I/O (read/write) requests.
302 *
303 * FIXME: this function needs a rename
304 */
305
306 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
307 {
308 ide_startstop_t startstop;
309
310 BUG_ON(!blk_rq_started(rq));
311
312 #ifdef DEBUG
313 printk("%s: start_request: current=0x%08lx\n",
314 drive->hwif->name, (unsigned long) rq);
315 #endif
316
317 /* bail early if we've exceeded max_failures */
318 if (drive->max_failures && (drive->failures > drive->max_failures)) {
319 rq->cmd_flags |= REQ_FAILED;
320 goto kill_rq;
321 }
322
323 if (blk_pm_request(rq))
324 ide_check_pm_state(drive, rq);
325
326 drive->hwif->tp_ops->dev_select(drive);
327 if (ide_wait_stat(&startstop, drive, drive->ready_stat,
328 ATA_BUSY | ATA_DRQ, WAIT_READY)) {
329 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
330 return startstop;
331 }
332
333 if (drive->special_flags == 0) {
334 struct ide_driver *drv;
335
336 /*
337 * We reset the drive so we need to issue a SETFEATURES.
338 * Do it _after_ do_special() restored device parameters.
339 */
340 if (drive->current_speed == 0xff)
341 ide_config_drive_speed(drive, drive->desired_speed);
342
343 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
344 return execute_drive_cmd(drive, rq);
345 else if (blk_pm_request(rq)) {
346 struct request_pm_state *pm = rq->special;
347 #ifdef DEBUG_PM
348 printk("%s: start_power_step(step: %d)\n",
349 drive->name, pm->pm_step);
350 #endif
351 startstop = ide_start_power_step(drive, rq);
352 if (startstop == ide_stopped &&
353 pm->pm_step == IDE_PM_COMPLETED)
354 ide_complete_pm_rq(drive, rq);
355 return startstop;
356 } else if (!rq->rq_disk && blk_special_request(rq))
357 /*
358 * TODO: Once all ULDs have been modified to
359 * check for specific op codes rather than
360 * blindly accepting any special request, the
361 * check for ->rq_disk above may be replaced
362 * by a more suitable mechanism or even
363 * dropped entirely.
364 */
365 return ide_special_rq(drive, rq);
366
367 drv = *(struct ide_driver **)rq->rq_disk->private_data;
368
369 return drv->do_request(drive, rq, blk_rq_pos(rq));
370 }
371 return do_special(drive);
372 kill_rq:
373 ide_kill_rq(drive, rq);
374 return ide_stopped;
375 }
376
377 /**
378 * ide_stall_queue - pause an IDE device
379 * @drive: drive to stall
380 * @timeout: time to stall for (jiffies)
381 *
382 * ide_stall_queue() can be used by a drive to give excess bandwidth back
383 * to the port by sleeping for timeout jiffies.
384 */
385
386 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
387 {
388 if (timeout > WAIT_WORSTCASE)
389 timeout = WAIT_WORSTCASE;
390 drive->sleep = timeout + jiffies;
391 drive->dev_flags |= IDE_DFLAG_SLEEPING;
392 }
393 EXPORT_SYMBOL(ide_stall_queue);
394
395 static inline int ide_lock_port(ide_hwif_t *hwif)
396 {
397 if (hwif->busy)
398 return 1;
399
400 hwif->busy = 1;
401
402 return 0;
403 }
404
405 static inline void ide_unlock_port(ide_hwif_t *hwif)
406 {
407 hwif->busy = 0;
408 }
409
410 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
411 {
412 int rc = 0;
413
414 if (host->host_flags & IDE_HFLAG_SERIALIZE) {
415 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
416 if (rc == 0) {
417 if (host->get_lock)
418 host->get_lock(ide_intr, hwif);
419 }
420 }
421 return rc;
422 }
423
424 static inline void ide_unlock_host(struct ide_host *host)
425 {
426 if (host->host_flags & IDE_HFLAG_SERIALIZE) {
427 if (host->release_lock)
428 host->release_lock();
429 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
430 }
431 }
432
433 /*
434 * Issue a new request to a device.
435 */
436 void do_ide_request(struct request_queue *q)
437 {
438 ide_drive_t *drive = q->queuedata;
439 ide_hwif_t *hwif = drive->hwif;
440 struct ide_host *host = hwif->host;
441 struct request *rq = NULL;
442 ide_startstop_t startstop;
443
444 /*
445 * drive is doing pre-flush, ordered write, post-flush sequence. even
446 * though that is 3 requests, it must be seen as a single transaction.
447 * we must not preempt this drive until that is complete
448 */
449 if (blk_queue_flushing(q))
450 /*
451 * small race where queue could get replugged during
452 * the 3-request flush cycle, just yank the plug since
453 * we want it to finish asap
454 */
455 blk_remove_plug(q);
456
457 spin_unlock_irq(q->queue_lock);
458
459 /* HLD do_request() callback might sleep, make sure it's okay */
460 might_sleep();
461
462 if (ide_lock_host(host, hwif))
463 goto plug_device_2;
464
465 spin_lock_irq(&hwif->lock);
466
467 if (!ide_lock_port(hwif)) {
468 ide_hwif_t *prev_port;
469
470 WARN_ON_ONCE(hwif->rq);
471 repeat:
472 prev_port = hwif->host->cur_port;
473 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
474 time_after(drive->sleep, jiffies)) {
475 ide_unlock_port(hwif);
476 goto plug_device;
477 }
478
479 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
480 hwif != prev_port) {
481 ide_drive_t *cur_dev =
482 prev_port ? prev_port->cur_dev : NULL;
483
484 /*
485 * set nIEN for previous port, drives in the
486 * quirk list may not like intr setups/cleanups
487 */
488 if (cur_dev &&
489 (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
490 prev_port->tp_ops->write_devctl(prev_port,
491 ATA_NIEN |
492 ATA_DEVCTL_OBS);
493
494 hwif->host->cur_port = hwif;
495 }
496 hwif->cur_dev = drive;
497 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
498
499 spin_unlock_irq(&hwif->lock);
500 spin_lock_irq(q->queue_lock);
501 /*
502 * we know that the queue isn't empty, but this can happen
503 * if the q->prep_rq_fn() decides to kill a request
504 */
505 if (!rq)
506 rq = blk_fetch_request(drive->queue);
507
508 spin_unlock_irq(q->queue_lock);
509 spin_lock_irq(&hwif->lock);
510
511 if (!rq) {
512 ide_unlock_port(hwif);
513 goto out;
514 }
515
516 /*
517 * Sanity: don't accept a request that isn't a PM request
518 * if we are currently power managed. This is very important as
519 * blk_stop_queue() doesn't prevent the blk_fetch_request()
520 * above to return us whatever is in the queue. Since we call
521 * ide_do_request() ourselves, we end up taking requests while
522 * the queue is blocked...
523 *
524 * We let requests forced at head of queue with ide-preempt
525 * though. I hope that doesn't happen too much, hopefully not
526 * unless the subdriver triggers such a thing in its own PM
527 * state machine.
528 */
529 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
530 blk_pm_request(rq) == 0 &&
531 (rq->cmd_flags & REQ_PREEMPT) == 0) {
532 /* there should be no pending command at this point */
533 ide_unlock_port(hwif);
534 goto plug_device;
535 }
536
537 hwif->rq = rq;
538
539 spin_unlock_irq(&hwif->lock);
540 startstop = start_request(drive, rq);
541 spin_lock_irq(&hwif->lock);
542
543 if (startstop == ide_stopped) {
544 rq = hwif->rq;
545 hwif->rq = NULL;
546 goto repeat;
547 }
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 (rq)
564 blk_requeue_request(q, rq);
565 if (!elv_queue_empty(q))
566 blk_plug_device(q);
567 }
568
569 static void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
570 {
571 struct request_queue *q = drive->queue;
572 unsigned long flags;
573
574 spin_lock_irqsave(q->queue_lock, flags);
575
576 if (rq)
577 blk_requeue_request(q, rq);
578 if (!elv_queue_empty(q))
579 blk_plug_device(q);
580
581 spin_unlock_irqrestore(q->queue_lock, flags);
582 }
583
584 static int drive_is_ready(ide_drive_t *drive)
585 {
586 ide_hwif_t *hwif = drive->hwif;
587 u8 stat = 0;
588
589 if (drive->waiting_for_dma)
590 return hwif->dma_ops->dma_test_irq(drive);
591
592 if (hwif->io_ports.ctl_addr &&
593 (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
594 stat = hwif->tp_ops->read_altstatus(hwif);
595 else
596 /* Note: this may clear a pending IRQ!! */
597 stat = hwif->tp_ops->read_status(hwif);
598
599 if (stat & ATA_BUSY)
600 /* drive busy: definitely not interrupting */
601 return 0;
602
603 /* drive ready: *might* be interrupting */
604 return 1;
605 }
606
607 /**
608 * ide_timer_expiry - handle lack of an IDE interrupt
609 * @data: timer callback magic (hwif)
610 *
611 * An IDE command has timed out before the expected drive return
612 * occurred. At this point we attempt to clean up the current
613 * mess. If the current handler includes an expiry handler then
614 * we invoke the expiry handler, and providing it is happy the
615 * work is done. If that fails we apply generic recovery rules
616 * invoking the handler and checking the drive DMA status. We
617 * have an excessively incestuous relationship with the DMA
618 * logic that wants cleaning up.
619 */
620
621 void ide_timer_expiry (unsigned long data)
622 {
623 ide_hwif_t *hwif = (ide_hwif_t *)data;
624 ide_drive_t *uninitialized_var(drive);
625 ide_handler_t *handler;
626 unsigned long flags;
627 int wait = -1;
628 int plug_device = 0;
629 struct request *uninitialized_var(rq_in_flight);
630
631 spin_lock_irqsave(&hwif->lock, flags);
632
633 handler = hwif->handler;
634
635 if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
636 /*
637 * Either a marginal timeout occurred
638 * (got the interrupt just as timer expired),
639 * or we were "sleeping" to give other devices a chance.
640 * Either way, we don't really want to complain about anything.
641 */
642 } else {
643 ide_expiry_t *expiry = hwif->expiry;
644 ide_startstop_t startstop = ide_stopped;
645
646 drive = hwif->cur_dev;
647
648 if (expiry) {
649 wait = expiry(drive);
650 if (wait > 0) { /* continue */
651 /* reset timer */
652 hwif->timer.expires = jiffies + wait;
653 hwif->req_gen_timer = hwif->req_gen;
654 add_timer(&hwif->timer);
655 spin_unlock_irqrestore(&hwif->lock, flags);
656 return;
657 }
658 }
659 hwif->handler = NULL;
660 hwif->expiry = NULL;
661 /*
662 * We need to simulate a real interrupt when invoking
663 * the handler() function, which means we need to
664 * globally mask the specific IRQ:
665 */
666 spin_unlock(&hwif->lock);
667 /* disable_irq_nosync ?? */
668 disable_irq(hwif->irq);
669 /* local CPU only, as if we were handling an interrupt */
670 local_irq_disable();
671 if (hwif->polling) {
672 startstop = handler(drive);
673 } else if (drive_is_ready(drive)) {
674 if (drive->waiting_for_dma)
675 hwif->dma_ops->dma_lost_irq(drive);
676 if (hwif->port_ops && hwif->port_ops->clear_irq)
677 hwif->port_ops->clear_irq(drive);
678
679 printk(KERN_WARNING "%s: lost interrupt\n",
680 drive->name);
681 startstop = handler(drive);
682 } else {
683 if (drive->waiting_for_dma)
684 startstop = ide_dma_timeout_retry(drive, wait);
685 else
686 startstop = ide_error(drive, "irq timeout",
687 hwif->tp_ops->read_status(hwif));
688 }
689 spin_lock_irq(&hwif->lock);
690 enable_irq(hwif->irq);
691 if (startstop == ide_stopped && hwif->polling == 0) {
692 rq_in_flight = hwif->rq;
693 hwif->rq = NULL;
694 ide_unlock_port(hwif);
695 plug_device = 1;
696 }
697 }
698 spin_unlock_irqrestore(&hwif->lock, flags);
699
700 if (plug_device) {
701 ide_unlock_host(hwif->host);
702 ide_requeue_and_plug(drive, rq_in_flight);
703 }
704 }
705
706 /**
707 * unexpected_intr - handle an unexpected IDE interrupt
708 * @irq: interrupt line
709 * @hwif: port being processed
710 *
711 * There's nothing really useful we can do with an unexpected interrupt,
712 * other than reading the status register (to clear it), and logging it.
713 * There should be no way that an irq can happen before we're ready for it,
714 * so we needn't worry much about losing an "important" interrupt here.
715 *
716 * On laptops (and "green" PCs), an unexpected interrupt occurs whenever
717 * the drive enters "idle", "standby", or "sleep" mode, so if the status
718 * looks "good", we just ignore the interrupt completely.
719 *
720 * This routine assumes __cli() is in effect when called.
721 *
722 * If an unexpected interrupt happens on irq15 while we are handling irq14
723 * and if the two interfaces are "serialized" (CMD640), then it looks like
724 * we could screw up by interfering with a new request being set up for
725 * irq15.
726 *
727 * In reality, this is a non-issue. The new command is not sent unless
728 * the drive is ready to accept one, in which case we know the drive is
729 * not trying to interrupt us. And ide_set_handler() is always invoked
730 * before completing the issuance of any new drive command, so we will not
731 * be accidentally invoked as a result of any valid command completion
732 * interrupt.
733 */
734
735 static void unexpected_intr(int irq, ide_hwif_t *hwif)
736 {
737 u8 stat = hwif->tp_ops->read_status(hwif);
738
739 if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
740 /* Try to not flood the console with msgs */
741 static unsigned long last_msgtime, count;
742 ++count;
743
744 if (time_after(jiffies, last_msgtime + HZ)) {
745 last_msgtime = jiffies;
746 printk(KERN_ERR "%s: unexpected interrupt, "
747 "status=0x%02x, count=%ld\n",
748 hwif->name, stat, count);
749 }
750 }
751 }
752
753 /**
754 * ide_intr - default IDE interrupt handler
755 * @irq: interrupt number
756 * @dev_id: hwif
757 * @regs: unused weirdness from the kernel irq layer
758 *
759 * This is the default IRQ handler for the IDE layer. You should
760 * not need to override it. If you do be aware it is subtle in
761 * places
762 *
763 * hwif is the interface in the group currently performing
764 * a command. hwif->cur_dev is the drive and hwif->handler is
765 * the IRQ handler to call. As we issue a command the handlers
766 * step through multiple states, reassigning the handler to the
767 * next step in the process. Unlike a smart SCSI controller IDE
768 * expects the main processor to sequence the various transfer
769 * stages. We also manage a poll timer to catch up with most
770 * timeout situations. There are still a few where the handlers
771 * don't ever decide to give up.
772 *
773 * The handler eventually returns ide_stopped to indicate the
774 * request completed. At this point we issue the next request
775 * on the port and the process begins again.
776 */
777
778 irqreturn_t ide_intr (int irq, void *dev_id)
779 {
780 ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
781 struct ide_host *host = hwif->host;
782 ide_drive_t *uninitialized_var(drive);
783 ide_handler_t *handler;
784 unsigned long flags;
785 ide_startstop_t startstop;
786 irqreturn_t irq_ret = IRQ_NONE;
787 int plug_device = 0;
788 struct request *uninitialized_var(rq_in_flight);
789
790 if (host->host_flags & IDE_HFLAG_SERIALIZE) {
791 if (hwif != host->cur_port)
792 goto out_early;
793 }
794
795 spin_lock_irqsave(&hwif->lock, flags);
796
797 if (hwif->port_ops && hwif->port_ops->test_irq &&
798 hwif->port_ops->test_irq(hwif) == 0)
799 goto out;
800
801 handler = hwif->handler;
802
803 if (handler == NULL || hwif->polling) {
804 /*
805 * Not expecting an interrupt from this drive.
806 * That means this could be:
807 * (1) an interrupt from another PCI device
808 * sharing the same PCI INT# as us.
809 * or (2) a drive just entered sleep or standby mode,
810 * and is interrupting to let us know.
811 * or (3) a spurious interrupt of unknown origin.
812 *
813 * For PCI, we cannot tell the difference,
814 * so in that case we just ignore it and hope it goes away.
815 */
816 if ((host->irq_flags & IRQF_SHARED) == 0) {
817 /*
818 * Probably not a shared PCI interrupt,
819 * so we can safely try to do something about it:
820 */
821 unexpected_intr(irq, hwif);
822 } else {
823 /*
824 * Whack the status register, just in case
825 * we have a leftover pending IRQ.
826 */
827 (void)hwif->tp_ops->read_status(hwif);
828 }
829 goto out;
830 }
831
832 drive = hwif->cur_dev;
833
834 if (!drive_is_ready(drive))
835 /*
836 * This happens regularly when we share a PCI IRQ with
837 * another device. Unfortunately, it can also happen
838 * with some buggy drives that trigger the IRQ before
839 * their status register is up to date. Hopefully we have
840 * enough advance overhead that the latter isn't a problem.
841 */
842 goto out;
843
844 hwif->handler = NULL;
845 hwif->expiry = NULL;
846 hwif->req_gen++;
847 del_timer(&hwif->timer);
848 spin_unlock(&hwif->lock);
849
850 if (hwif->port_ops && hwif->port_ops->clear_irq)
851 hwif->port_ops->clear_irq(drive);
852
853 if (drive->dev_flags & IDE_DFLAG_UNMASK)
854 local_irq_enable_in_hardirq();
855
856 /* service this interrupt, may set handler for next interrupt */
857 startstop = handler(drive);
858
859 spin_lock_irq(&hwif->lock);
860 /*
861 * Note that handler() may have set things up for another
862 * interrupt to occur soon, but it cannot happen until
863 * we exit from this routine, because it will be the
864 * same irq as is currently being serviced here, and Linux
865 * won't allow another of the same (on any CPU) until we return.
866 */
867 if (startstop == ide_stopped && hwif->polling == 0) {
868 BUG_ON(hwif->handler);
869 rq_in_flight = hwif->rq;
870 hwif->rq = NULL;
871 ide_unlock_port(hwif);
872 plug_device = 1;
873 }
874 irq_ret = IRQ_HANDLED;
875 out:
876 spin_unlock_irqrestore(&hwif->lock, flags);
877 out_early:
878 if (plug_device) {
879 ide_unlock_host(hwif->host);
880 ide_requeue_and_plug(drive, rq_in_flight);
881 }
882
883 return irq_ret;
884 }
885 EXPORT_SYMBOL_GPL(ide_intr);
886
887 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
888 {
889 ide_hwif_t *hwif = drive->hwif;
890 u8 buf[4] = { 0 };
891
892 while (len > 0) {
893 if (write)
894 hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
895 else
896 hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
897 len -= 4;
898 }
899 }
900 EXPORT_SYMBOL_GPL(ide_pad_transfer);
901
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