ide: move data register access out of tf_{read|load}() methods (take 2)
[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         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                 tf->data = data[0];
90                 tf->hob_data = data[1];
91         }
92
93         tp_ops->tf_read(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, tf);
101                 } else
102                         drive->dev_flags |= IDE_DFLAG_PARKED;
103         }
104
105         if (rq && rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
106                 memcpy(rq->special, cmd, sizeof(*cmd));
107
108         if (cmd->tf_flags & IDE_TFLAG_DYN)
109                 kfree(cmd);
110 }
111
112 /* obsolete, blk_rq_bytes() should be used instead */
113 unsigned int ide_rq_bytes(struct request *rq)
114 {
115         if (blk_pc_request(rq))
116                 return rq->data_len;
117         else
118                 return rq->hard_cur_sectors << 9;
119 }
120 EXPORT_SYMBOL_GPL(ide_rq_bytes);
121
122 int ide_complete_rq(ide_drive_t *drive, int error, unsigned int nr_bytes)
123 {
124         ide_hwif_t *hwif = drive->hwif;
125         struct request *rq = hwif->rq;
126         int rc;
127
128         /*
129          * if failfast is set on a request, override number of sectors
130          * and complete the whole request right now
131          */
132         if (blk_noretry_request(rq) && error <= 0)
133                 nr_bytes = rq->hard_nr_sectors << 9;
134
135         rc = ide_end_rq(drive, rq, error, nr_bytes);
136         if (rc == 0)
137                 hwif->rq = NULL;
138
139         return rc;
140 }
141 EXPORT_SYMBOL(ide_complete_rq);
142
143 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
144 {
145         u8 drv_req = blk_special_request(rq) && rq->rq_disk;
146         u8 media = drive->media;
147
148         drive->failed_pc = NULL;
149
150         if ((media == ide_floppy || media == ide_tape) && drv_req) {
151                 rq->errors = 0;
152                 ide_complete_rq(drive, 0, blk_rq_bytes(rq));
153         } else {
154                 if (media == ide_tape)
155                         rq->errors = IDE_DRV_ERROR_GENERAL;
156                 else if (blk_fs_request(rq) == 0 && rq->errors == 0)
157                         rq->errors = -EIO;
158                 ide_complete_rq(drive, -EIO, ide_rq_bytes(rq));
159         }
160 }
161
162 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
163 {
164         tf->nsect   = drive->sect;
165         tf->lbal    = drive->sect;
166         tf->lbam    = drive->cyl;
167         tf->lbah    = drive->cyl >> 8;
168         tf->device  = (drive->head - 1) | drive->select;
169         tf->command = ATA_CMD_INIT_DEV_PARAMS;
170 }
171
172 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
173 {
174         tf->nsect   = drive->sect;
175         tf->command = ATA_CMD_RESTORE;
176 }
177
178 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
179 {
180         tf->nsect   = drive->mult_req;
181         tf->command = ATA_CMD_SET_MULTI;
182 }
183
184 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
185 {
186         special_t *s = &drive->special;
187         struct ide_cmd cmd;
188
189         memset(&cmd, 0, sizeof(cmd));
190         cmd.protocol = ATA_PROT_NODATA;
191
192         if (s->b.set_geometry) {
193                 s->b.set_geometry = 0;
194                 ide_tf_set_specify_cmd(drive, &cmd.tf);
195         } else if (s->b.recalibrate) {
196                 s->b.recalibrate = 0;
197                 ide_tf_set_restore_cmd(drive, &cmd.tf);
198         } else if (s->b.set_multmode) {
199                 s->b.set_multmode = 0;
200                 ide_tf_set_setmult_cmd(drive, &cmd.tf);
201         } else if (s->all) {
202                 int special = s->all;
203                 s->all = 0;
204                 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
205                 return ide_stopped;
206         }
207
208         cmd.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE |
209                        IDE_TFLAG_CUSTOM_HANDLER;
210
211         do_rw_taskfile(drive, &cmd);
212
213         return ide_started;
214 }
215
216 /**
217  *      do_special              -       issue some special commands
218  *      @drive: drive the command is for
219  *
220  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
221  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
222  *
223  *      It used to do much more, but has been scaled back.
224  */
225
226 static ide_startstop_t do_special (ide_drive_t *drive)
227 {
228         special_t *s = &drive->special;
229
230 #ifdef DEBUG
231         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
232 #endif
233         if (drive->media == ide_disk)
234                 return ide_disk_special(drive);
235
236         s->all = 0;
237         drive->mult_req = 0;
238         return ide_stopped;
239 }
240
241 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
242 {
243         ide_hwif_t *hwif = drive->hwif;
244         struct scatterlist *sg = hwif->sg_table;
245         struct request *rq = cmd->rq;
246
247         if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
248                 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
249                 cmd->sg_nents = 1;
250         } else if (!rq->bio) {
251                 sg_init_one(sg, rq->data, rq->data_len);
252                 cmd->sg_nents = 1;
253         } else
254                 cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
255 }
256 EXPORT_SYMBOL_GPL(ide_map_sg);
257
258 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
259 {
260         cmd->nbytes = cmd->nleft = nr_bytes;
261         cmd->cursg_ofs = 0;
262         cmd->cursg = NULL;
263 }
264 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
265
266 /**
267  *      execute_drive_command   -       issue special drive command
268  *      @drive: the drive to issue the command on
269  *      @rq: the request structure holding the command
270  *
271  *      execute_drive_cmd() issues a special drive command,  usually 
272  *      initiated by ioctl() from the external hdparm program. The
273  *      command can be a drive command, drive task or taskfile 
274  *      operation. Weirdly you can call it with NULL to wait for
275  *      all commands to finish. Don't do this as that is due to change
276  */
277
278 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
279                 struct request *rq)
280 {
281         struct ide_cmd *cmd = rq->special;
282
283         if (cmd) {
284                 if (cmd->protocol == ATA_PROT_PIO) {
285                         ide_init_sg_cmd(cmd, rq->nr_sectors << 9);
286                         ide_map_sg(drive, cmd);
287                 }
288
289                 return do_rw_taskfile(drive, cmd);
290         }
291
292         /*
293          * NULL is actually a valid way of waiting for
294          * all current requests to be flushed from the queue.
295          */
296 #ifdef DEBUG
297         printk("%s: DRIVE_CMD (null)\n", drive->name);
298 #endif
299         rq->errors = 0;
300         ide_complete_rq(drive, 0, blk_rq_bytes(rq));
301
302         return ide_stopped;
303 }
304
305 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
306 {
307         u8 cmd = rq->cmd[0];
308
309         switch (cmd) {
310         case REQ_PARK_HEADS:
311         case REQ_UNPARK_HEADS:
312                 return ide_do_park_unpark(drive, rq);
313         case REQ_DEVSET_EXEC:
314                 return ide_do_devset(drive, rq);
315         case REQ_DRIVE_RESET:
316                 return ide_do_reset(drive);
317         default:
318                 BUG();
319         }
320 }
321
322 /**
323  *      start_request   -       start of I/O and command issuing for IDE
324  *
325  *      start_request() initiates handling of a new I/O request. It
326  *      accepts commands and I/O (read/write) requests.
327  *
328  *      FIXME: this function needs a rename
329  */
330  
331 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
332 {
333         ide_startstop_t startstop;
334
335         BUG_ON(!blk_rq_started(rq));
336
337 #ifdef DEBUG
338         printk("%s: start_request: current=0x%08lx\n",
339                 drive->hwif->name, (unsigned long) rq);
340 #endif
341
342         /* bail early if we've exceeded max_failures */
343         if (drive->max_failures && (drive->failures > drive->max_failures)) {
344                 rq->cmd_flags |= REQ_FAILED;
345                 goto kill_rq;
346         }
347
348         if (blk_pm_request(rq))
349                 ide_check_pm_state(drive, rq);
350
351         SELECT_DRIVE(drive);
352         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
353                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
354                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
355                 return startstop;
356         }
357         if (!drive->special.all) {
358                 struct ide_driver *drv;
359
360                 /*
361                  * We reset the drive so we need to issue a SETFEATURES.
362                  * Do it _after_ do_special() restored device parameters.
363                  */
364                 if (drive->current_speed == 0xff)
365                         ide_config_drive_speed(drive, drive->desired_speed);
366
367                 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
368                         return execute_drive_cmd(drive, rq);
369                 else if (blk_pm_request(rq)) {
370                         struct request_pm_state *pm = rq->data;
371 #ifdef DEBUG_PM
372                         printk("%s: start_power_step(step: %d)\n",
373                                 drive->name, pm->pm_step);
374 #endif
375                         startstop = ide_start_power_step(drive, rq);
376                         if (startstop == ide_stopped &&
377                             pm->pm_step == IDE_PM_COMPLETED)
378                                 ide_complete_pm_rq(drive, rq);
379                         return startstop;
380                 } else if (!rq->rq_disk && blk_special_request(rq))
381                         /*
382                          * TODO: Once all ULDs have been modified to
383                          * check for specific op codes rather than
384                          * blindly accepting any special request, the
385                          * check for ->rq_disk above may be replaced
386                          * by a more suitable mechanism or even
387                          * dropped entirely.
388                          */
389                         return ide_special_rq(drive, rq);
390
391                 drv = *(struct ide_driver **)rq->rq_disk->private_data;
392
393                 return drv->do_request(drive, rq, rq->sector);
394         }
395         return do_special(drive);
396 kill_rq:
397         ide_kill_rq(drive, rq);
398         return ide_stopped;
399 }
400
401 /**
402  *      ide_stall_queue         -       pause an IDE device
403  *      @drive: drive to stall
404  *      @timeout: time to stall for (jiffies)
405  *
406  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
407  *      to the port by sleeping for timeout jiffies.
408  */
409  
410 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
411 {
412         if (timeout > WAIT_WORSTCASE)
413                 timeout = WAIT_WORSTCASE;
414         drive->sleep = timeout + jiffies;
415         drive->dev_flags |= IDE_DFLAG_SLEEPING;
416 }
417 EXPORT_SYMBOL(ide_stall_queue);
418
419 static inline int ide_lock_port(ide_hwif_t *hwif)
420 {
421         if (hwif->busy)
422                 return 1;
423
424         hwif->busy = 1;
425
426         return 0;
427 }
428
429 static inline void ide_unlock_port(ide_hwif_t *hwif)
430 {
431         hwif->busy = 0;
432 }
433
434 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
435 {
436         int rc = 0;
437
438         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
439                 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
440                 if (rc == 0) {
441                         if (host->get_lock)
442                                 host->get_lock(ide_intr, hwif);
443                 }
444         }
445         return rc;
446 }
447
448 static inline void ide_unlock_host(struct ide_host *host)
449 {
450         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
451                 if (host->release_lock)
452                         host->release_lock();
453                 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
454         }
455 }
456
457 /*
458  * Issue a new request to a device.
459  */
460 void do_ide_request(struct request_queue *q)
461 {
462         ide_drive_t     *drive = q->queuedata;
463         ide_hwif_t      *hwif = drive->hwif;
464         struct ide_host *host = hwif->host;
465         struct request  *rq = NULL;
466         ide_startstop_t startstop;
467
468         /*
469          * drive is doing pre-flush, ordered write, post-flush sequence. even
470          * though that is 3 requests, it must be seen as a single transaction.
471          * we must not preempt this drive until that is complete
472          */
473         if (blk_queue_flushing(q))
474                 /*
475                  * small race where queue could get replugged during
476                  * the 3-request flush cycle, just yank the plug since
477                  * we want it to finish asap
478                  */
479                 blk_remove_plug(q);
480
481         spin_unlock_irq(q->queue_lock);
482
483         if (ide_lock_host(host, hwif))
484                 goto plug_device_2;
485
486         spin_lock_irq(&hwif->lock);
487
488         if (!ide_lock_port(hwif)) {
489                 ide_hwif_t *prev_port;
490 repeat:
491                 prev_port = hwif->host->cur_port;
492                 hwif->rq = NULL;
493
494                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
495                     time_after(drive->sleep, jiffies)) {
496                         ide_unlock_port(hwif);
497                         goto plug_device;
498                 }
499
500                 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
501                     hwif != prev_port) {
502                         /*
503                          * set nIEN for previous port, drives in the
504                          * quirk_list may not like intr setups/cleanups
505                          */
506                         if (prev_port && prev_port->cur_dev->quirk_list == 0)
507                                 prev_port->tp_ops->write_devctl(prev_port,
508                                                                 ATA_NIEN |
509                                                                 ATA_DEVCTL_OBS);
510
511                         hwif->host->cur_port = hwif;
512                 }
513                 hwif->cur_dev = drive;
514                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
515
516                 spin_unlock_irq(&hwif->lock);
517                 spin_lock_irq(q->queue_lock);
518                 /*
519                  * we know that the queue isn't empty, but this can happen
520                  * if the q->prep_rq_fn() decides to kill a request
521                  */
522                 rq = elv_next_request(drive->queue);
523                 spin_unlock_irq(q->queue_lock);
524                 spin_lock_irq(&hwif->lock);
525
526                 if (!rq) {
527                         ide_unlock_port(hwif);
528                         goto out;
529                 }
530
531                 /*
532                  * Sanity: don't accept a request that isn't a PM request
533                  * if we are currently power managed. This is very important as
534                  * blk_stop_queue() doesn't prevent the elv_next_request()
535                  * above to return us whatever is in the queue. Since we call
536                  * ide_do_request() ourselves, we end up taking requests while
537                  * the queue is blocked...
538                  * 
539                  * We let requests forced at head of queue with ide-preempt
540                  * though. I hope that doesn't happen too much, hopefully not
541                  * unless the subdriver triggers such a thing in its own PM
542                  * state machine.
543                  */
544                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
545                     blk_pm_request(rq) == 0 &&
546                     (rq->cmd_flags & REQ_PREEMPT) == 0) {
547                         /* there should be no pending command at this point */
548                         ide_unlock_port(hwif);
549                         goto plug_device;
550                 }
551
552                 hwif->rq = rq;
553
554                 spin_unlock_irq(&hwif->lock);
555                 startstop = start_request(drive, rq);
556                 spin_lock_irq(&hwif->lock);
557
558                 if (startstop == ide_stopped)
559                         goto repeat;
560         } else
561                 goto plug_device;
562 out:
563         spin_unlock_irq(&hwif->lock);
564         if (rq == NULL)
565                 ide_unlock_host(host);
566         spin_lock_irq(q->queue_lock);
567         return;
568
569 plug_device:
570         spin_unlock_irq(&hwif->lock);
571         ide_unlock_host(host);
572 plug_device_2:
573         spin_lock_irq(q->queue_lock);
574
575         if (!elv_queue_empty(q))
576                 blk_plug_device(q);
577 }
578
579 static void ide_plug_device(ide_drive_t *drive)
580 {
581         struct request_queue *q = drive->queue;
582         unsigned long flags;
583
584         spin_lock_irqsave(q->queue_lock, flags);
585         if (!elv_queue_empty(q))
586                 blk_plug_device(q);
587         spin_unlock_irqrestore(q->queue_lock, flags);
588 }
589
590 static int drive_is_ready(ide_drive_t *drive)
591 {
592         ide_hwif_t *hwif = drive->hwif;
593         u8 stat = 0;
594
595         if (drive->waiting_for_dma)
596                 return hwif->dma_ops->dma_test_irq(drive);
597
598         if (hwif->io_ports.ctl_addr &&
599             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
600                 stat = hwif->tp_ops->read_altstatus(hwif);
601         else
602                 /* Note: this may clear a pending IRQ!! */
603                 stat = hwif->tp_ops->read_status(hwif);
604
605         if (stat & ATA_BUSY)
606                 /* drive busy: definitely not interrupting */
607                 return 0;
608
609         /* drive ready: *might* be interrupting */
610         return 1;
611 }
612
613 /**
614  *      ide_timer_expiry        -       handle lack of an IDE interrupt
615  *      @data: timer callback magic (hwif)
616  *
617  *      An IDE command has timed out before the expected drive return
618  *      occurred. At this point we attempt to clean up the current
619  *      mess. If the current handler includes an expiry handler then
620  *      we invoke the expiry handler, and providing it is happy the
621  *      work is done. If that fails we apply generic recovery rules
622  *      invoking the handler and checking the drive DMA status. We
623  *      have an excessively incestuous relationship with the DMA
624  *      logic that wants cleaning up.
625  */
626  
627 void ide_timer_expiry (unsigned long data)
628 {
629         ide_hwif_t      *hwif = (ide_hwif_t *)data;
630         ide_drive_t     *uninitialized_var(drive);
631         ide_handler_t   *handler;
632         unsigned long   flags;
633         int             wait = -1;
634         int             plug_device = 0;
635
636         spin_lock_irqsave(&hwif->lock, flags);
637
638         handler = hwif->handler;
639
640         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
641                 /*
642                  * Either a marginal timeout occurred
643                  * (got the interrupt just as timer expired),
644                  * or we were "sleeping" to give other devices a chance.
645                  * Either way, we don't really want to complain about anything.
646                  */
647         } else {
648                 ide_expiry_t *expiry = hwif->expiry;
649                 ide_startstop_t startstop = ide_stopped;
650
651                 drive = hwif->cur_dev;
652
653                 if (expiry) {
654                         wait = expiry(drive);
655                         if (wait > 0) { /* continue */
656                                 /* reset timer */
657                                 hwif->timer.expires = jiffies + wait;
658                                 hwif->req_gen_timer = hwif->req_gen;
659                                 add_timer(&hwif->timer);
660                                 spin_unlock_irqrestore(&hwif->lock, flags);
661                                 return;
662                         }
663                 }
664                 hwif->handler = NULL;
665                 hwif->expiry = NULL;
666                 /*
667                  * We need to simulate a real interrupt when invoking
668                  * the handler() function, which means we need to
669                  * globally mask the specific IRQ:
670                  */
671                 spin_unlock(&hwif->lock);
672                 /* disable_irq_nosync ?? */
673                 disable_irq(hwif->irq);
674                 /* local CPU only, as if we were handling an interrupt */
675                 local_irq_disable();
676                 if (hwif->polling) {
677                         startstop = handler(drive);
678                 } else if (drive_is_ready(drive)) {
679                         if (drive->waiting_for_dma)
680                                 hwif->dma_ops->dma_lost_irq(drive);
681                         if (hwif->ack_intr)
682                                 hwif->ack_intr(hwif);
683                         printk(KERN_WARNING "%s: lost interrupt\n",
684                                 drive->name);
685                         startstop = handler(drive);
686                 } else {
687                         if (drive->waiting_for_dma)
688                                 startstop = ide_dma_timeout_retry(drive, wait);
689                         else
690                                 startstop = ide_error(drive, "irq timeout",
691                                         hwif->tp_ops->read_status(hwif));
692                 }
693                 spin_lock_irq(&hwif->lock);
694                 enable_irq(hwif->irq);
695                 if (startstop == ide_stopped) {
696                         ide_unlock_port(hwif);
697                         plug_device = 1;
698                 }
699         }
700         spin_unlock_irqrestore(&hwif->lock, flags);
701
702         if (plug_device) {
703                 ide_unlock_host(hwif->host);
704                 ide_plug_device(drive);
705         }
706 }
707
708 /**
709  *      unexpected_intr         -       handle an unexpected IDE interrupt
710  *      @irq: interrupt line
711  *      @hwif: port being processed
712  *
713  *      There's nothing really useful we can do with an unexpected interrupt,
714  *      other than reading the status register (to clear it), and logging it.
715  *      There should be no way that an irq can happen before we're ready for it,
716  *      so we needn't worry much about losing an "important" interrupt here.
717  *
718  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
719  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
720  *      looks "good", we just ignore the interrupt completely.
721  *
722  *      This routine assumes __cli() is in effect when called.
723  *
724  *      If an unexpected interrupt happens on irq15 while we are handling irq14
725  *      and if the two interfaces are "serialized" (CMD640), then it looks like
726  *      we could screw up by interfering with a new request being set up for 
727  *      irq15.
728  *
729  *      In reality, this is a non-issue.  The new command is not sent unless 
730  *      the drive is ready to accept one, in which case we know the drive is
731  *      not trying to interrupt us.  And ide_set_handler() is always invoked
732  *      before completing the issuance of any new drive command, so we will not
733  *      be accidentally invoked as a result of any valid command completion
734  *      interrupt.
735  */
736
737 static void unexpected_intr(int irq, ide_hwif_t *hwif)
738 {
739         u8 stat = hwif->tp_ops->read_status(hwif);
740
741         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
742                 /* Try to not flood the console with msgs */
743                 static unsigned long last_msgtime, count;
744                 ++count;
745
746                 if (time_after(jiffies, last_msgtime + HZ)) {
747                         last_msgtime = jiffies;
748                         printk(KERN_ERR "%s: unexpected interrupt, "
749                                 "status=0x%02x, count=%ld\n",
750                                 hwif->name, stat, count);
751                 }
752         }
753 }
754
755 /**
756  *      ide_intr        -       default IDE interrupt handler
757  *      @irq: interrupt number
758  *      @dev_id: hwif
759  *      @regs: unused weirdness from the kernel irq layer
760  *
761  *      This is the default IRQ handler for the IDE layer. You should
762  *      not need to override it. If you do be aware it is subtle in
763  *      places
764  *
765  *      hwif is the interface in the group currently performing
766  *      a command. hwif->cur_dev is the drive and hwif->handler is
767  *      the IRQ handler to call. As we issue a command the handlers
768  *      step through multiple states, reassigning the handler to the
769  *      next step in the process. Unlike a smart SCSI controller IDE
770  *      expects the main processor to sequence the various transfer
771  *      stages. We also manage a poll timer to catch up with most
772  *      timeout situations. There are still a few where the handlers
773  *      don't ever decide to give up.
774  *
775  *      The handler eventually returns ide_stopped to indicate the
776  *      request completed. At this point we issue the next request
777  *      on the port and the process begins again.
778  */
779
780 irqreturn_t ide_intr (int irq, void *dev_id)
781 {
782         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
783         struct ide_host *host = hwif->host;
784         ide_drive_t *uninitialized_var(drive);
785         ide_handler_t *handler;
786         unsigned long flags;
787         ide_startstop_t startstop;
788         irqreturn_t irq_ret = IRQ_NONE;
789         int plug_device = 0;
790
791         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
792                 if (hwif != host->cur_port)
793                         goto out_early;
794         }
795
796         spin_lock_irqsave(&hwif->lock, flags);
797
798         if (hwif->ack_intr && hwif->ack_intr(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) {
868                 BUG_ON(hwif->handler);
869                 ide_unlock_port(hwif);
870                 plug_device = 1;
871         }
872         irq_ret = IRQ_HANDLED;
873 out:
874         spin_unlock_irqrestore(&hwif->lock, flags);
875 out_early:
876         if (plug_device) {
877                 ide_unlock_host(hwif->host);
878                 ide_plug_device(drive);
879         }
880
881         return irq_ret;
882 }
883 EXPORT_SYMBOL_GPL(ide_intr);
884
885 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
886 {
887         ide_hwif_t *hwif = drive->hwif;
888         u8 buf[4] = { 0 };
889
890         while (len > 0) {
891                 if (write)
892                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
893                 else
894                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
895                 len -= 4;
896         }
897 }
898 EXPORT_SYMBOL_GPL(ide_pad_transfer);