4 * Basic PIO and command management functionality.
6 * This code was split off from ide.c. See ide.c for history and original
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
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.
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.
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>
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>
52 #include <asm/byteorder.h>
54 #include <asm/uaccess.h>
57 int ide_end_rq(ide_drive_t
*drive
, struct request
*rq
, int error
,
58 unsigned int nr_bytes
)
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
64 if ((drive
->dev_flags
& IDE_DFLAG_DMA_PIO_RETRY
) &&
65 drive
->retry_pio
<= 3) {
66 drive
->dev_flags
&= ~IDE_DFLAG_DMA_PIO_RETRY
;
70 return blk_end_request(rq
, error
, nr_bytes
);
72 EXPORT_SYMBOL_GPL(ide_end_rq
);
74 void ide_complete_cmd(ide_drive_t
*drive
, struct ide_cmd
*cmd
, u8 stat
, u8 err
)
76 struct ide_taskfile
*tf
= &cmd
->tf
;
77 struct request
*rq
= cmd
->rq
;
78 u8 tf_cmd
= tf
->command
;
83 drive
->hwif
->tp_ops
->tf_read(drive
, cmd
);
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",
90 ide_tf_dump(drive
->name
, tf
);
92 drive
->dev_flags
|= IDE_DFLAG_PARKED
;
95 if (rq
&& rq
->cmd_type
== REQ_TYPE_ATA_TASKFILE
)
96 memcpy(rq
->special
, cmd
, sizeof(*cmd
));
98 if (cmd
->tf_flags
& IDE_TFLAG_DYN
)
102 /* obsolete, blk_rq_bytes() should be used instead */
103 unsigned int ide_rq_bytes(struct request
*rq
)
105 if (blk_pc_request(rq
))
108 return rq
->hard_cur_sectors
<< 9;
110 EXPORT_SYMBOL_GPL(ide_rq_bytes
);
112 int ide_complete_rq(ide_drive_t
*drive
, int error
, unsigned int nr_bytes
)
114 ide_hwif_t
*hwif
= drive
->hwif
;
115 struct request
*rq
= hwif
->rq
;
119 * if failfast is set on a request, override number of sectors
120 * and complete the whole request right now
122 if (blk_noretry_request(rq
) && error
<= 0)
123 nr_bytes
= rq
->hard_nr_sectors
<< 9;
125 rc
= ide_end_rq(drive
, rq
, error
, nr_bytes
);
131 EXPORT_SYMBOL(ide_complete_rq
);
133 void ide_kill_rq(ide_drive_t
*drive
, struct request
*rq
)
135 u8 drv_req
= blk_special_request(rq
) && rq
->rq_disk
;
136 u8 media
= drive
->media
;
138 drive
->failed_pc
= NULL
;
140 if ((media
== ide_floppy
|| media
== ide_tape
) && drv_req
) {
142 ide_complete_rq(drive
, 0, blk_rq_bytes(rq
));
144 if (media
== ide_tape
)
145 rq
->errors
= IDE_DRV_ERROR_GENERAL
;
146 else if (blk_fs_request(rq
) == 0 && rq
->errors
== 0)
148 ide_complete_rq(drive
, -EIO
, ide_rq_bytes(rq
));
152 static void ide_tf_set_specify_cmd(ide_drive_t
*drive
, struct ide_taskfile
*tf
)
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
;
162 static void ide_tf_set_restore_cmd(ide_drive_t
*drive
, struct ide_taskfile
*tf
)
164 tf
->nsect
= drive
->sect
;
165 tf
->command
= ATA_CMD_RESTORE
;
168 static void ide_tf_set_setmult_cmd(ide_drive_t
*drive
, struct ide_taskfile
*tf
)
170 tf
->nsect
= drive
->mult_req
;
171 tf
->command
= ATA_CMD_SET_MULTI
;
174 static ide_startstop_t
ide_disk_special(ide_drive_t
*drive
)
176 special_t
*s
= &drive
->special
;
179 memset(&cmd
, 0, sizeof(cmd
));
180 cmd
.protocol
= ATA_PROT_NODATA
;
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
);
192 int special
= s
->all
;
194 printk(KERN_ERR
"%s: bad special flag: 0x%02x\n", drive
->name
, special
);
198 cmd
.tf_flags
= IDE_TFLAG_TF
| IDE_TFLAG_DEVICE
|
199 IDE_TFLAG_CUSTOM_HANDLER
;
201 do_rw_taskfile(drive
, &cmd
);
207 * do_special - issue some special commands
208 * @drive: drive the command is for
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.
213 * It used to do much more, but has been scaled back.
216 static ide_startstop_t
do_special (ide_drive_t
*drive
)
218 special_t
*s
= &drive
->special
;
221 printk("%s: do_special: 0x%02x\n", drive
->name
, s
->all
);
223 if (drive
->media
== ide_disk
)
224 return ide_disk_special(drive
);
231 void ide_map_sg(ide_drive_t
*drive
, struct request
*rq
)
233 ide_hwif_t
*hwif
= drive
->hwif
;
234 struct ide_cmd
*cmd
= &hwif
->cmd
;
235 struct scatterlist
*sg
= hwif
->sg_table
;
237 if (rq
->cmd_type
== REQ_TYPE_ATA_TASKFILE
) {
238 sg_init_one(sg
, rq
->buffer
, rq
->nr_sectors
* SECTOR_SIZE
);
240 } else if (!rq
->bio
) {
241 sg_init_one(sg
, rq
->data
, rq
->data_len
);
244 cmd
->sg_nents
= blk_rq_map_sg(drive
->queue
, rq
, sg
);
246 EXPORT_SYMBOL_GPL(ide_map_sg
);
248 void ide_init_sg_cmd(struct ide_cmd
*cmd
, int nsect
)
250 cmd
->nsect
= cmd
->nleft
= nsect
;
254 EXPORT_SYMBOL_GPL(ide_init_sg_cmd
);
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
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
268 static ide_startstop_t
execute_drive_cmd (ide_drive_t
*drive
,
271 struct ide_cmd
*cmd
= rq
->special
;
274 if (cmd
->protocol
== ATA_PROT_PIO
) {
275 ide_init_sg_cmd(cmd
, rq
->nr_sectors
);
276 ide_map_sg(drive
, rq
);
279 return do_rw_taskfile(drive
, cmd
);
283 * NULL is actually a valid way of waiting for
284 * all current requests to be flushed from the queue.
287 printk("%s: DRIVE_CMD (null)\n", drive
->name
);
290 ide_complete_rq(drive
, 0, blk_rq_bytes(rq
));
295 static ide_startstop_t
ide_special_rq(ide_drive_t
*drive
, struct request
*rq
)
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
);
313 * start_request - start of I/O and command issuing for IDE
315 * start_request() initiates handling of a new I/O request. It
316 * accepts commands and I/O (read/write) requests.
318 * FIXME: this function needs a rename
321 static ide_startstop_t
start_request (ide_drive_t
*drive
, struct request
*rq
)
323 ide_startstop_t startstop
;
325 BUG_ON(!blk_rq_started(rq
));
328 printk("%s: start_request: current=0x%08lx\n",
329 drive
->hwif
->name
, (unsigned long) rq
);
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
;
338 if (blk_pm_request(rq
))
339 ide_check_pm_state(drive
, rq
);
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
);
347 if (!drive
->special
.all
) {
348 struct ide_driver
*drv
;
351 * We reset the drive so we need to issue a SETFEATURES.
352 * Do it _after_ do_special() restored device parameters.
354 if (drive
->current_speed
== 0xff)
355 ide_config_drive_speed(drive
, drive
->desired_speed
);
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
;
362 printk("%s: start_power_step(step: %d)\n",
363 drive
->name
, pm
->pm_step
);
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
);
370 } else if (!rq
->rq_disk
&& blk_special_request(rq
))
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
379 return ide_special_rq(drive
, rq
);
381 drv
= *(struct ide_driver
**)rq
->rq_disk
->private_data
;
383 return drv
->do_request(drive
, rq
, rq
->sector
);
385 return do_special(drive
);
387 ide_kill_rq(drive
, rq
);
392 * ide_stall_queue - pause an IDE device
393 * @drive: drive to stall
394 * @timeout: time to stall for (jiffies)
396 * ide_stall_queue() can be used by a drive to give excess bandwidth back
397 * to the port by sleeping for timeout jiffies.
400 void ide_stall_queue (ide_drive_t
*drive
, unsigned long timeout
)
402 if (timeout
> WAIT_WORSTCASE
)
403 timeout
= WAIT_WORSTCASE
;
404 drive
->sleep
= timeout
+ jiffies
;
405 drive
->dev_flags
|= IDE_DFLAG_SLEEPING
;
407 EXPORT_SYMBOL(ide_stall_queue
);
409 static inline int ide_lock_port(ide_hwif_t
*hwif
)
419 static inline void ide_unlock_port(ide_hwif_t
*hwif
)
424 static inline int ide_lock_host(struct ide_host
*host
, ide_hwif_t
*hwif
)
428 if (host
->host_flags
& IDE_HFLAG_SERIALIZE
) {
429 rc
= test_and_set_bit_lock(IDE_HOST_BUSY
, &host
->host_busy
);
432 host
->get_lock(ide_intr
, hwif
);
438 static inline void ide_unlock_host(struct ide_host
*host
)
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
);
448 * Issue a new request to a device.
450 void do_ide_request(struct request_queue
*q
)
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
;
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
463 if (blk_queue_flushing(q
))
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
471 spin_unlock_irq(q
->queue_lock
);
473 if (ide_lock_host(host
, hwif
))
476 spin_lock_irq(&hwif
->lock
);
478 if (!ide_lock_port(hwif
)) {
479 ide_hwif_t
*prev_port
;
481 prev_port
= hwif
->host
->cur_port
;
484 if (drive
->dev_flags
& IDE_DFLAG_SLEEPING
) {
485 if (time_before(drive
->sleep
, jiffies
)) {
486 ide_unlock_port(hwif
);
491 if ((hwif
->host
->host_flags
& IDE_HFLAG_SERIALIZE
) &&
494 * set nIEN for previous port, drives in the
495 * quirk_list may not like intr setups/cleanups
497 if (prev_port
&& prev_port
->cur_dev
->quirk_list
== 0)
498 prev_port
->tp_ops
->set_irq(prev_port
, 0);
500 hwif
->host
->cur_port
= hwif
;
502 hwif
->cur_dev
= drive
;
503 drive
->dev_flags
&= ~(IDE_DFLAG_SLEEPING
| IDE_DFLAG_PARKED
);
505 spin_unlock_irq(&hwif
->lock
);
506 spin_lock_irq(q
->queue_lock
);
508 * we know that the queue isn't empty, but this can happen
509 * if the q->prep_rq_fn() decides to kill a request
511 rq
= elv_next_request(drive
->queue
);
512 spin_unlock_irq(q
->queue_lock
);
513 spin_lock_irq(&hwif
->lock
);
516 ide_unlock_port(hwif
);
521 * Sanity: don't accept a request that isn't a PM request
522 * if we are currently power managed. This is very important as
523 * blk_stop_queue() doesn't prevent the elv_next_request()
524 * above to return us whatever is in the queue. Since we call
525 * ide_do_request() ourselves, we end up taking requests while
526 * the queue is blocked...
528 * We let requests forced at head of queue with ide-preempt
529 * though. I hope that doesn't happen too much, hopefully not
530 * unless the subdriver triggers such a thing in its own PM
533 if ((drive
->dev_flags
& IDE_DFLAG_BLOCKED
) &&
534 blk_pm_request(rq
) == 0 &&
535 (rq
->cmd_flags
& REQ_PREEMPT
) == 0) {
536 /* there should be no pending command at this point */
537 ide_unlock_port(hwif
);
543 spin_unlock_irq(&hwif
->lock
);
544 startstop
= start_request(drive
, rq
);
545 spin_lock_irq(&hwif
->lock
);
547 if (startstop
== ide_stopped
)
552 spin_unlock_irq(&hwif
->lock
);
554 ide_unlock_host(host
);
555 spin_lock_irq(q
->queue_lock
);
559 spin_unlock_irq(&hwif
->lock
);
560 ide_unlock_host(host
);
562 spin_lock_irq(q
->queue_lock
);
564 if (!elv_queue_empty(q
))
568 static void ide_plug_device(ide_drive_t
*drive
)
570 struct request_queue
*q
= drive
->queue
;
573 spin_lock_irqsave(q
->queue_lock
, flags
);
574 if (!elv_queue_empty(q
))
576 spin_unlock_irqrestore(q
->queue_lock
, flags
);
579 static int drive_is_ready(ide_drive_t
*drive
)
581 ide_hwif_t
*hwif
= drive
->hwif
;
584 if (drive
->waiting_for_dma
)
585 return hwif
->dma_ops
->dma_test_irq(drive
);
587 if (hwif
->io_ports
.ctl_addr
&&
588 (hwif
->host_flags
& IDE_HFLAG_BROKEN_ALTSTATUS
) == 0)
589 stat
= hwif
->tp_ops
->read_altstatus(hwif
);
591 /* Note: this may clear a pending IRQ!! */
592 stat
= hwif
->tp_ops
->read_status(hwif
);
595 /* drive busy: definitely not interrupting */
598 /* drive ready: *might* be interrupting */
603 * ide_timer_expiry - handle lack of an IDE interrupt
604 * @data: timer callback magic (hwif)
606 * An IDE command has timed out before the expected drive return
607 * occurred. At this point we attempt to clean up the current
608 * mess. If the current handler includes an expiry handler then
609 * we invoke the expiry handler, and providing it is happy the
610 * work is done. If that fails we apply generic recovery rules
611 * invoking the handler and checking the drive DMA status. We
612 * have an excessively incestuous relationship with the DMA
613 * logic that wants cleaning up.
616 void ide_timer_expiry (unsigned long data
)
618 ide_hwif_t
*hwif
= (ide_hwif_t
*)data
;
619 ide_drive_t
*uninitialized_var(drive
);
620 ide_handler_t
*handler
;
625 spin_lock_irqsave(&hwif
->lock
, flags
);
627 handler
= hwif
->handler
;
629 if (handler
== NULL
|| hwif
->req_gen
!= hwif
->req_gen_timer
) {
631 * Either a marginal timeout occurred
632 * (got the interrupt just as timer expired),
633 * or we were "sleeping" to give other devices a chance.
634 * Either way, we don't really want to complain about anything.
637 ide_expiry_t
*expiry
= hwif
->expiry
;
638 ide_startstop_t startstop
= ide_stopped
;
640 drive
= hwif
->cur_dev
;
643 wait
= expiry(drive
);
644 if (wait
> 0) { /* continue */
646 hwif
->timer
.expires
= jiffies
+ wait
;
647 hwif
->req_gen_timer
= hwif
->req_gen
;
648 add_timer(&hwif
->timer
);
649 spin_unlock_irqrestore(&hwif
->lock
, flags
);
653 hwif
->handler
= NULL
;
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:
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 */
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
);
670 hwif
->ack_intr(hwif
);
671 printk(KERN_WARNING
"%s: lost interrupt\n",
673 startstop
= handler(drive
);
675 if (drive
->waiting_for_dma
)
676 startstop
= ide_dma_timeout_retry(drive
, wait
);
678 startstop
= ide_error(drive
, "irq timeout",
679 hwif
->tp_ops
->read_status(hwif
));
681 spin_lock_irq(&hwif
->lock
);
682 enable_irq(hwif
->irq
);
683 if (startstop
== ide_stopped
) {
684 ide_unlock_port(hwif
);
688 spin_unlock_irqrestore(&hwif
->lock
, flags
);
691 ide_unlock_host(hwif
->host
);
692 ide_plug_device(drive
);
697 * unexpected_intr - handle an unexpected IDE interrupt
698 * @irq: interrupt line
699 * @hwif: port being processed
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.
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.
710 * This routine assumes __cli() is in effect when called.
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
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
725 static void unexpected_intr(int irq
, ide_hwif_t
*hwif
)
727 u8 stat
= hwif
->tp_ops
->read_status(hwif
);
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
;
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
);
744 * ide_intr - default IDE interrupt handler
745 * @irq: interrupt number
747 * @regs: unused weirdness from the kernel irq layer
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
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.
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.
768 irqreturn_t
ide_intr (int irq
, void *dev_id
)
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
;
775 ide_startstop_t startstop
;
776 irqreturn_t irq_ret
= IRQ_NONE
;
779 if (host
->host_flags
& IDE_HFLAG_SERIALIZE
) {
780 if (hwif
!= host
->cur_port
)
784 spin_lock_irqsave(&hwif
->lock
, flags
);
786 if (hwif
->ack_intr
&& hwif
->ack_intr(hwif
) == 0)
789 handler
= hwif
->handler
;
791 if (handler
== NULL
|| hwif
->polling
) {
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.
801 * For PCI, we cannot tell the difference,
802 * so in that case we just ignore it and hope it goes away.
804 if ((host
->irq_flags
& IRQF_SHARED
) == 0) {
806 * Probably not a shared PCI interrupt,
807 * so we can safely try to do something about it:
809 unexpected_intr(irq
, hwif
);
812 * Whack the status register, just in case
813 * we have a leftover pending IRQ.
815 (void)hwif
->tp_ops
->read_status(hwif
);
820 drive
= hwif
->cur_dev
;
822 if (!drive_is_ready(drive
))
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.
832 hwif
->handler
= NULL
;
834 del_timer(&hwif
->timer
);
835 spin_unlock(&hwif
->lock
);
837 if (hwif
->port_ops
&& hwif
->port_ops
->clear_irq
)
838 hwif
->port_ops
->clear_irq(drive
);
840 if (drive
->dev_flags
& IDE_DFLAG_UNMASK
)
841 local_irq_enable_in_hardirq();
843 /* service this interrupt, may set handler for next interrupt */
844 startstop
= handler(drive
);
846 spin_lock_irq(&hwif
->lock
);
848 * Note that handler() may have set things up for another
849 * interrupt to occur soon, but it cannot happen until
850 * we exit from this routine, because it will be the
851 * same irq as is currently being serviced here, and Linux
852 * won't allow another of the same (on any CPU) until we return.
854 if (startstop
== ide_stopped
) {
855 BUG_ON(hwif
->handler
);
856 ide_unlock_port(hwif
);
859 irq_ret
= IRQ_HANDLED
;
861 spin_unlock_irqrestore(&hwif
->lock
, flags
);
864 ide_unlock_host(hwif
->host
);
865 ide_plug_device(drive
);
870 EXPORT_SYMBOL_GPL(ide_intr
);
872 void ide_pad_transfer(ide_drive_t
*drive
, int write
, int len
)
874 ide_hwif_t
*hwif
= drive
->hwif
;
879 hwif
->tp_ops
->output_data(drive
, NULL
, buf
, min(4, len
));
881 hwif
->tp_ops
->input_data(drive
, NULL
, buf
, min(4, len
));
885 EXPORT_SYMBOL_GPL(ide_pad_transfer
);