5b57905a7d713e5174980d38ee642bd6758a837c
[linux-3.10.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->write_devctl(prev_port,
498                                                                 ATA_NIEN |
499                                                                 ATA_DEVCTL_OBS);
500
501                         hwif->host->cur_port = hwif;
502                 }
503                 hwif->cur_dev = drive;
504                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
505
506                 spin_unlock_irq(&hwif->lock);
507                 spin_lock_irq(q->queue_lock);
508                 /*
509                  * we know that the queue isn't empty, but this can happen
510                  * if the q->prep_rq_fn() decides to kill a request
511                  */
512                 rq = elv_next_request(drive->queue);
513                 spin_unlock_irq(q->queue_lock);
514                 spin_lock_irq(&hwif->lock);
515
516                 if (!rq) {
517                         ide_unlock_port(hwif);
518                         goto out;
519                 }
520
521                 /*
522                  * Sanity: don't accept a request that isn't a PM request
523                  * if we are currently power managed. This is very important as
524                  * blk_stop_queue() doesn't prevent the elv_next_request()
525                  * above to return us whatever is in the queue. Since we call
526                  * ide_do_request() ourselves, we end up taking requests while
527                  * the queue is blocked...
528                  * 
529                  * We let requests forced at head of queue with ide-preempt
530                  * though. I hope that doesn't happen too much, hopefully not
531                  * unless the subdriver triggers such a thing in its own PM
532                  * state machine.
533                  */
534                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
535                     blk_pm_request(rq) == 0 &&
536                     (rq->cmd_flags & REQ_PREEMPT) == 0) {
537                         /* there should be no pending command at this point */
538                         ide_unlock_port(hwif);
539                         goto plug_device;
540                 }
541
542                 hwif->rq = rq;
543
544                 spin_unlock_irq(&hwif->lock);
545                 startstop = start_request(drive, rq);
546                 spin_lock_irq(&hwif->lock);
547
548                 if (startstop == ide_stopped)
549                         goto repeat;
550         } else
551                 goto plug_device;
552 out:
553         spin_unlock_irq(&hwif->lock);
554         if (rq == NULL)
555                 ide_unlock_host(host);
556         spin_lock_irq(q->queue_lock);
557         return;
558
559 plug_device:
560         spin_unlock_irq(&hwif->lock);
561         ide_unlock_host(host);
562 plug_device_2:
563         spin_lock_irq(q->queue_lock);
564
565         if (!elv_queue_empty(q))
566                 blk_plug_device(q);
567 }
568
569 static void ide_plug_device(ide_drive_t *drive)
570 {
571         struct request_queue *q = drive->queue;
572         unsigned long flags;
573
574         spin_lock_irqsave(q->queue_lock, flags);
575         if (!elv_queue_empty(q))
576                 blk_plug_device(q);
577         spin_unlock_irqrestore(q->queue_lock, flags);
578 }
579
580 static int drive_is_ready(ide_drive_t *drive)
581 {
582         ide_hwif_t *hwif = drive->hwif;
583         u8 stat = 0;
584
585         if (drive->waiting_for_dma)
586                 return hwif->dma_ops->dma_test_irq(drive);
587
588         if (hwif->io_ports.ctl_addr &&
589             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
590                 stat = hwif->tp_ops->read_altstatus(hwif);
591         else
592                 /* Note: this may clear a pending IRQ!! */
593                 stat = hwif->tp_ops->read_status(hwif);
594
595         if (stat & ATA_BUSY)
596                 /* drive busy: definitely not interrupting */
597                 return 0;
598
599         /* drive ready: *might* be interrupting */
600         return 1;
601 }
602
603 /**
604  *      ide_timer_expiry        -       handle lack of an IDE interrupt
605  *      @data: timer callback magic (hwif)
606  *
607  *      An IDE command has timed out before the expected drive return
608  *      occurred. At this point we attempt to clean up the current
609  *      mess. If the current handler includes an expiry handler then
610  *      we invoke the expiry handler, and providing it is happy the
611  *      work is done. If that fails we apply generic recovery rules
612  *      invoking the handler and checking the drive DMA status. We
613  *      have an excessively incestuous relationship with the DMA
614  *      logic that wants cleaning up.
615  */
616  
617 void ide_timer_expiry (unsigned long data)
618 {
619         ide_hwif_t      *hwif = (ide_hwif_t *)data;
620         ide_drive_t     *uninitialized_var(drive);
621         ide_handler_t   *handler;
622         unsigned long   flags;
623         int             wait = -1;
624         int             plug_device = 0;
625
626         spin_lock_irqsave(&hwif->lock, flags);
627
628         handler = hwif->handler;
629
630         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
631                 /*
632                  * Either a marginal timeout occurred
633                  * (got the interrupt just as timer expired),
634                  * or we were "sleeping" to give other devices a chance.
635                  * Either way, we don't really want to complain about anything.
636                  */
637         } else {
638                 ide_expiry_t *expiry = hwif->expiry;
639                 ide_startstop_t startstop = ide_stopped;
640
641                 drive = hwif->cur_dev;
642
643                 if (expiry) {
644                         wait = expiry(drive);
645                         if (wait > 0) { /* continue */
646                                 /* reset timer */
647                                 hwif->timer.expires = jiffies + wait;
648                                 hwif->req_gen_timer = hwif->req_gen;
649                                 add_timer(&hwif->timer);
650                                 spin_unlock_irqrestore(&hwif->lock, flags);
651                                 return;
652                         }
653                 }
654                 hwif->handler = NULL;
655                 hwif->expiry = NULL;
656                 /*
657                  * We need to simulate a real interrupt when invoking
658                  * the handler() function, which means we need to
659                  * globally mask the specific IRQ:
660                  */
661                 spin_unlock(&hwif->lock);
662                 /* disable_irq_nosync ?? */
663                 disable_irq(hwif->irq);
664                 /* local CPU only, as if we were handling an interrupt */
665                 local_irq_disable();
666                 if (hwif->polling) {
667                         startstop = handler(drive);
668                 } else if (drive_is_ready(drive)) {
669                         if (drive->waiting_for_dma)
670                                 hwif->dma_ops->dma_lost_irq(drive);
671                         if (hwif->ack_intr)
672                                 hwif->ack_intr(hwif);
673                         printk(KERN_WARNING "%s: lost interrupt\n",
674                                 drive->name);
675                         startstop = handler(drive);
676                 } else {
677                         if (drive->waiting_for_dma)
678                                 startstop = ide_dma_timeout_retry(drive, wait);
679                         else
680                                 startstop = ide_error(drive, "irq timeout",
681                                         hwif->tp_ops->read_status(hwif));
682                 }
683                 spin_lock_irq(&hwif->lock);
684                 enable_irq(hwif->irq);
685                 if (startstop == ide_stopped) {
686                         ide_unlock_port(hwif);
687                         plug_device = 1;
688                 }
689         }
690         spin_unlock_irqrestore(&hwif->lock, flags);
691
692         if (plug_device) {
693                 ide_unlock_host(hwif->host);
694                 ide_plug_device(drive);
695         }
696 }
697
698 /**
699  *      unexpected_intr         -       handle an unexpected IDE interrupt
700  *      @irq: interrupt line
701  *      @hwif: port being processed
702  *
703  *      There's nothing really useful we can do with an unexpected interrupt,
704  *      other than reading the status register (to clear it), and logging it.
705  *      There should be no way that an irq can happen before we're ready for it,
706  *      so we needn't worry much about losing an "important" interrupt here.
707  *
708  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
709  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
710  *      looks "good", we just ignore the interrupt completely.
711  *
712  *      This routine assumes __cli() is in effect when called.
713  *
714  *      If an unexpected interrupt happens on irq15 while we are handling irq14
715  *      and if the two interfaces are "serialized" (CMD640), then it looks like
716  *      we could screw up by interfering with a new request being set up for 
717  *      irq15.
718  *
719  *      In reality, this is a non-issue.  The new command is not sent unless 
720  *      the drive is ready to accept one, in which case we know the drive is
721  *      not trying to interrupt us.  And ide_set_handler() is always invoked
722  *      before completing the issuance of any new drive command, so we will not
723  *      be accidentally invoked as a result of any valid command completion
724  *      interrupt.
725  */
726
727 static void unexpected_intr(int irq, ide_hwif_t *hwif)
728 {
729         u8 stat = hwif->tp_ops->read_status(hwif);
730
731         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
732                 /* Try to not flood the console with msgs */
733                 static unsigned long last_msgtime, count;
734                 ++count;
735
736                 if (time_after(jiffies, last_msgtime + HZ)) {
737                         last_msgtime = jiffies;
738                         printk(KERN_ERR "%s: unexpected interrupt, "
739                                 "status=0x%02x, count=%ld\n",
740                                 hwif->name, stat, count);
741                 }
742         }
743 }
744
745 /**
746  *      ide_intr        -       default IDE interrupt handler
747  *      @irq: interrupt number
748  *      @dev_id: hwif
749  *      @regs: unused weirdness from the kernel irq layer
750  *
751  *      This is the default IRQ handler for the IDE layer. You should
752  *      not need to override it. If you do be aware it is subtle in
753  *      places
754  *
755  *      hwif is the interface in the group currently performing
756  *      a command. hwif->cur_dev is the drive and hwif->handler is
757  *      the IRQ handler to call. As we issue a command the handlers
758  *      step through multiple states, reassigning the handler to the
759  *      next step in the process. Unlike a smart SCSI controller IDE
760  *      expects the main processor to sequence the various transfer
761  *      stages. We also manage a poll timer to catch up with most
762  *      timeout situations. There are still a few where the handlers
763  *      don't ever decide to give up.
764  *
765  *      The handler eventually returns ide_stopped to indicate the
766  *      request completed. At this point we issue the next request
767  *      on the port and the process begins again.
768  */
769
770 irqreturn_t ide_intr (int irq, void *dev_id)
771 {
772         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
773         struct ide_host *host = hwif->host;
774         ide_drive_t *uninitialized_var(drive);
775         ide_handler_t *handler;
776         unsigned long flags;
777         ide_startstop_t startstop;
778         irqreturn_t irq_ret = IRQ_NONE;
779         int plug_device = 0;
780
781         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
782                 if (hwif != host->cur_port)
783                         goto out_early;
784         }
785
786         spin_lock_irqsave(&hwif->lock, flags);
787
788         if (hwif->ack_intr && hwif->ack_intr(hwif) == 0)
789                 goto out;
790
791         handler = hwif->handler;
792
793         if (handler == NULL || hwif->polling) {
794                 /*
795                  * Not expecting an interrupt from this drive.
796                  * That means this could be:
797                  *      (1) an interrupt from another PCI device
798                  *      sharing the same PCI INT# as us.
799                  * or   (2) a drive just entered sleep or standby mode,
800                  *      and is interrupting to let us know.
801                  * or   (3) a spurious interrupt of unknown origin.
802                  *
803                  * For PCI, we cannot tell the difference,
804                  * so in that case we just ignore it and hope it goes away.
805                  */
806                 if ((host->irq_flags & IRQF_SHARED) == 0) {
807                         /*
808                          * Probably not a shared PCI interrupt,
809                          * so we can safely try to do something about it:
810                          */
811                         unexpected_intr(irq, hwif);
812                 } else {
813                         /*
814                          * Whack the status register, just in case
815                          * we have a leftover pending IRQ.
816                          */
817                         (void)hwif->tp_ops->read_status(hwif);
818                 }
819                 goto out;
820         }
821
822         drive = hwif->cur_dev;
823
824         if (!drive_is_ready(drive))
825                 /*
826                  * This happens regularly when we share a PCI IRQ with
827                  * another device.  Unfortunately, it can also happen
828                  * with some buggy drives that trigger the IRQ before
829                  * their status register is up to date.  Hopefully we have
830                  * enough advance overhead that the latter isn't a problem.
831                  */
832                 goto out;
833
834         hwif->handler = NULL;
835         hwif->expiry = NULL;
836         hwif->req_gen++;
837         del_timer(&hwif->timer);
838         spin_unlock(&hwif->lock);
839
840         if (hwif->port_ops && hwif->port_ops->clear_irq)
841                 hwif->port_ops->clear_irq(drive);
842
843         if (drive->dev_flags & IDE_DFLAG_UNMASK)
844                 local_irq_enable_in_hardirq();
845
846         /* service this interrupt, may set handler for next interrupt */
847         startstop = handler(drive);
848
849         spin_lock_irq(&hwif->lock);
850         /*
851          * Note that handler() may have set things up for another
852          * interrupt to occur soon, but it cannot happen until
853          * we exit from this routine, because it will be the
854          * same irq as is currently being serviced here, and Linux
855          * won't allow another of the same (on any CPU) until we return.
856          */
857         if (startstop == ide_stopped) {
858                 BUG_ON(hwif->handler);
859                 ide_unlock_port(hwif);
860                 plug_device = 1;
861         }
862         irq_ret = IRQ_HANDLED;
863 out:
864         spin_unlock_irqrestore(&hwif->lock, flags);
865 out_early:
866         if (plug_device) {
867                 ide_unlock_host(hwif->host);
868                 ide_plug_device(drive);
869         }
870
871         return irq_ret;
872 }
873 EXPORT_SYMBOL_GPL(ide_intr);
874
875 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
876 {
877         ide_hwif_t *hwif = drive->hwif;
878         u8 buf[4] = { 0 };
879
880         while (len > 0) {
881                 if (write)
882                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
883                 else
884                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
885                 len -= 4;
886         }
887 }
888 EXPORT_SYMBOL_GPL(ide_pad_transfer);