block: remove __generic_unplug_device() from exports
[linux-2.6.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/hdreg.h>
44 #include <linux/completion.h>
45 #include <linux/reboot.h>
46 #include <linux/cdrom.h>
47 #include <linux/seq_file.h>
48 #include <linux/device.h>
49 #include <linux/kmod.h>
50 #include <linux/scatterlist.h>
51 #include <linux/bitops.h>
52
53 #include <asm/byteorder.h>
54 #include <asm/irq.h>
55 #include <asm/uaccess.h>
56 #include <asm/io.h>
57
58 static int __ide_end_request(ide_drive_t *drive, struct request *rq,
59                              int uptodate, unsigned int nr_bytes, int dequeue)
60 {
61         int ret = 1;
62         int error = 0;
63
64         if (uptodate <= 0)
65                 error = uptodate ? uptodate : -EIO;
66
67         /*
68          * if failfast is set on a request, override number of sectors and
69          * complete the whole request right now
70          */
71         if (blk_noretry_request(rq) && error)
72                 nr_bytes = rq->hard_nr_sectors << 9;
73
74         if (!blk_fs_request(rq) && error && !rq->errors)
75                 rq->errors = -EIO;
76
77         /*
78          * decide whether to reenable DMA -- 3 is a random magic for now,
79          * if we DMA timeout more than 3 times, just stay in PIO
80          */
81         if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
82             drive->retry_pio <= 3) {
83                 drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
84                 ide_dma_on(drive);
85         }
86
87         if (!__blk_end_request(rq, error, nr_bytes)) {
88                 if (dequeue)
89                         HWGROUP(drive)->rq = NULL;
90                 ret = 0;
91         }
92
93         return ret;
94 }
95
96 /**
97  *      ide_end_request         -       complete an IDE I/O
98  *      @drive: IDE device for the I/O
99  *      @uptodate:
100  *      @nr_sectors: number of sectors completed
101  *
102  *      This is our end_request wrapper function. We complete the I/O
103  *      update random number input and dequeue the request, which if
104  *      it was tagged may be out of order.
105  */
106
107 int ide_end_request (ide_drive_t *drive, int uptodate, int nr_sectors)
108 {
109         unsigned int nr_bytes = nr_sectors << 9;
110         struct request *rq;
111         unsigned long flags;
112         int ret = 1;
113
114         /*
115          * room for locking improvements here, the calls below don't
116          * need the queue lock held at all
117          */
118         spin_lock_irqsave(&ide_lock, flags);
119         rq = HWGROUP(drive)->rq;
120
121         if (!nr_bytes) {
122                 if (blk_pc_request(rq))
123                         nr_bytes = rq->data_len;
124                 else
125                         nr_bytes = rq->hard_cur_sectors << 9;
126         }
127
128         ret = __ide_end_request(drive, rq, uptodate, nr_bytes, 1);
129
130         spin_unlock_irqrestore(&ide_lock, flags);
131         return ret;
132 }
133 EXPORT_SYMBOL(ide_end_request);
134
135 static void ide_complete_power_step(ide_drive_t *drive, struct request *rq, u8 stat, u8 error)
136 {
137         struct request_pm_state *pm = rq->data;
138
139         if (drive->media != ide_disk)
140                 return;
141
142         switch (pm->pm_step) {
143         case IDE_PM_FLUSH_CACHE:        /* Suspend step 1 (flush cache) */
144                 if (pm->pm_state == PM_EVENT_FREEZE)
145                         pm->pm_step = IDE_PM_COMPLETED;
146                 else
147                         pm->pm_step = IDE_PM_STANDBY;
148                 break;
149         case IDE_PM_STANDBY:            /* Suspend step 2 (standby) */
150                 pm->pm_step = IDE_PM_COMPLETED;
151                 break;
152         case IDE_PM_RESTORE_PIO:        /* Resume step 1 (restore PIO) */
153                 pm->pm_step = IDE_PM_IDLE;
154                 break;
155         case IDE_PM_IDLE:               /* Resume step 2 (idle)*/
156                 pm->pm_step = IDE_PM_RESTORE_DMA;
157                 break;
158         }
159 }
160
161 static ide_startstop_t ide_start_power_step(ide_drive_t *drive, struct request *rq)
162 {
163         struct request_pm_state *pm = rq->data;
164         ide_task_t *args = rq->special;
165
166         memset(args, 0, sizeof(*args));
167
168         switch (pm->pm_step) {
169         case IDE_PM_FLUSH_CACHE:        /* Suspend step 1 (flush cache) */
170                 if (drive->media != ide_disk)
171                         break;
172                 /* Not supported? Switch to next step now. */
173                 if (ata_id_flush_enabled(drive->id) == 0 ||
174                     (drive->dev_flags & IDE_DFLAG_WCACHE) == 0) {
175                         ide_complete_power_step(drive, rq, 0, 0);
176                         return ide_stopped;
177                 }
178                 if (ata_id_flush_ext_enabled(drive->id))
179                         args->tf.command = ATA_CMD_FLUSH_EXT;
180                 else
181                         args->tf.command = ATA_CMD_FLUSH;
182                 goto out_do_tf;
183         case IDE_PM_STANDBY:            /* Suspend step 2 (standby) */
184                 args->tf.command = ATA_CMD_STANDBYNOW1;
185                 goto out_do_tf;
186         case IDE_PM_RESTORE_PIO:        /* Resume step 1 (restore PIO) */
187                 ide_set_max_pio(drive);
188                 /*
189                  * skip IDE_PM_IDLE for ATAPI devices
190                  */
191                 if (drive->media != ide_disk)
192                         pm->pm_step = IDE_PM_RESTORE_DMA;
193                 else
194                         ide_complete_power_step(drive, rq, 0, 0);
195                 return ide_stopped;
196         case IDE_PM_IDLE:               /* Resume step 2 (idle) */
197                 args->tf.command = ATA_CMD_IDLEIMMEDIATE;
198                 goto out_do_tf;
199         case IDE_PM_RESTORE_DMA:        /* Resume step 3 (restore DMA) */
200                 /*
201                  * Right now, all we do is call ide_set_dma(drive),
202                  * we could be smarter and check for current xfer_speed
203                  * in struct drive etc...
204                  */
205                 if (drive->hwif->dma_ops == NULL)
206                         break;
207                 /*
208                  * TODO: respect IDE_DFLAG_USING_DMA
209                  */
210                 ide_set_dma(drive);
211                 break;
212         }
213
214         pm->pm_step = IDE_PM_COMPLETED;
215         return ide_stopped;
216
217 out_do_tf:
218         args->tf_flags   = IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
219         args->data_phase = TASKFILE_NO_DATA;
220         return do_rw_taskfile(drive, args);
221 }
222
223 /**
224  *      ide_end_dequeued_request        -       complete an IDE I/O
225  *      @drive: IDE device for the I/O
226  *      @uptodate:
227  *      @nr_sectors: number of sectors completed
228  *
229  *      Complete an I/O that is no longer on the request queue. This
230  *      typically occurs when we pull the request and issue a REQUEST_SENSE.
231  *      We must still finish the old request but we must not tamper with the
232  *      queue in the meantime.
233  *
234  *      NOTE: This path does not handle barrier, but barrier is not supported
235  *      on ide-cd anyway.
236  */
237
238 int ide_end_dequeued_request(ide_drive_t *drive, struct request *rq,
239                              int uptodate, int nr_sectors)
240 {
241         unsigned long flags;
242         int ret;
243
244         spin_lock_irqsave(&ide_lock, flags);
245         BUG_ON(!blk_rq_started(rq));
246         ret = __ide_end_request(drive, rq, uptodate, nr_sectors << 9, 0);
247         spin_unlock_irqrestore(&ide_lock, flags);
248
249         return ret;
250 }
251 EXPORT_SYMBOL_GPL(ide_end_dequeued_request);
252
253
254 /**
255  *      ide_complete_pm_request - end the current Power Management request
256  *      @drive: target drive
257  *      @rq: request
258  *
259  *      This function cleans up the current PM request and stops the queue
260  *      if necessary.
261  */
262 static void ide_complete_pm_request (ide_drive_t *drive, struct request *rq)
263 {
264         unsigned long flags;
265
266 #ifdef DEBUG_PM
267         printk("%s: completing PM request, %s\n", drive->name,
268                blk_pm_suspend_request(rq) ? "suspend" : "resume");
269 #endif
270         spin_lock_irqsave(&ide_lock, flags);
271         if (blk_pm_suspend_request(rq)) {
272                 blk_stop_queue(drive->queue);
273         } else {
274                 drive->dev_flags &= ~IDE_DFLAG_BLOCKED;
275                 blk_start_queue(drive->queue);
276         }
277         HWGROUP(drive)->rq = NULL;
278         if (__blk_end_request(rq, 0, 0))
279                 BUG();
280         spin_unlock_irqrestore(&ide_lock, flags);
281 }
282
283 /**
284  *      ide_end_drive_cmd       -       end an explicit drive command
285  *      @drive: command 
286  *      @stat: status bits
287  *      @err: error bits
288  *
289  *      Clean up after success/failure of an explicit drive command.
290  *      These get thrown onto the queue so they are synchronized with
291  *      real I/O operations on the drive.
292  *
293  *      In LBA48 mode we have to read the register set twice to get
294  *      all the extra information out.
295  */
296  
297 void ide_end_drive_cmd (ide_drive_t *drive, u8 stat, u8 err)
298 {
299         unsigned long flags;
300         struct request *rq;
301
302         spin_lock_irqsave(&ide_lock, flags);
303         rq = HWGROUP(drive)->rq;
304         spin_unlock_irqrestore(&ide_lock, flags);
305
306         if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
307                 ide_task_t *task = (ide_task_t *)rq->special;
308
309                 if (rq->errors == 0)
310                         rq->errors = !OK_STAT(stat, ATA_DRDY, BAD_STAT);
311
312                 if (task) {
313                         struct ide_taskfile *tf = &task->tf;
314
315                         tf->error = err;
316                         tf->status = stat;
317
318                         drive->hwif->tp_ops->tf_read(drive, task);
319
320                         if (task->tf_flags & IDE_TFLAG_DYN)
321                                 kfree(task);
322                 }
323         } else if (blk_pm_request(rq)) {
324                 struct request_pm_state *pm = rq->data;
325 #ifdef DEBUG_PM
326                 printk("%s: complete_power_step(step: %d, stat: %x, err: %x)\n",
327                         drive->name, rq->pm->pm_step, stat, err);
328 #endif
329                 ide_complete_power_step(drive, rq, stat, err);
330                 if (pm->pm_step == IDE_PM_COMPLETED)
331                         ide_complete_pm_request(drive, rq);
332                 return;
333         }
334
335         spin_lock_irqsave(&ide_lock, flags);
336         HWGROUP(drive)->rq = NULL;
337         rq->errors = err;
338         if (unlikely(__blk_end_request(rq, (rq->errors ? -EIO : 0),
339                                        blk_rq_bytes(rq))))
340                 BUG();
341         spin_unlock_irqrestore(&ide_lock, flags);
342 }
343
344 EXPORT_SYMBOL(ide_end_drive_cmd);
345
346 static void ide_kill_rq(ide_drive_t *drive, struct request *rq)
347 {
348         if (rq->rq_disk) {
349                 ide_driver_t *drv;
350
351                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
352                 drv->end_request(drive, 0, 0);
353         } else
354                 ide_end_request(drive, 0, 0);
355 }
356
357 static ide_startstop_t ide_ata_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
358 {
359         ide_hwif_t *hwif = drive->hwif;
360
361         if ((stat & ATA_BUSY) ||
362             ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) {
363                 /* other bits are useless when BUSY */
364                 rq->errors |= ERROR_RESET;
365         } else if (stat & ATA_ERR) {
366                 /* err has different meaning on cdrom and tape */
367                 if (err == ATA_ABORTED) {
368                         if ((drive->dev_flags & IDE_DFLAG_LBA) &&
369                             /* some newer drives don't support ATA_CMD_INIT_DEV_PARAMS */
370                             hwif->tp_ops->read_status(hwif) == ATA_CMD_INIT_DEV_PARAMS)
371                                 return ide_stopped;
372                 } else if ((err & BAD_CRC) == BAD_CRC) {
373                         /* UDMA crc error, just retry the operation */
374                         drive->crc_count++;
375                 } else if (err & (ATA_BBK | ATA_UNC)) {
376                         /* retries won't help these */
377                         rq->errors = ERROR_MAX;
378                 } else if (err & ATA_TRK0NF) {
379                         /* help it find track zero */
380                         rq->errors |= ERROR_RECAL;
381                 }
382         }
383
384         if ((stat & ATA_DRQ) && rq_data_dir(rq) == READ &&
385             (hwif->host_flags & IDE_HFLAG_ERROR_STOPS_FIFO) == 0) {
386                 int nsect = drive->mult_count ? drive->mult_count : 1;
387
388                 ide_pad_transfer(drive, READ, nsect * SECTOR_SIZE);
389         }
390
391         if (rq->errors >= ERROR_MAX || blk_noretry_request(rq)) {
392                 ide_kill_rq(drive, rq);
393                 return ide_stopped;
394         }
395
396         if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
397                 rq->errors |= ERROR_RESET;
398
399         if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
400                 ++rq->errors;
401                 return ide_do_reset(drive);
402         }
403
404         if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
405                 drive->special.b.recalibrate = 1;
406
407         ++rq->errors;
408
409         return ide_stopped;
410 }
411
412 static ide_startstop_t ide_atapi_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
413 {
414         ide_hwif_t *hwif = drive->hwif;
415
416         if ((stat & ATA_BUSY) ||
417             ((stat & ATA_DF) && (drive->dev_flags & IDE_DFLAG_NOWERR) == 0)) {
418                 /* other bits are useless when BUSY */
419                 rq->errors |= ERROR_RESET;
420         } else {
421                 /* add decoding error stuff */
422         }
423
424         if (hwif->tp_ops->read_status(hwif) & (ATA_BUSY | ATA_DRQ))
425                 /* force an abort */
426                 hwif->tp_ops->exec_command(hwif, ATA_CMD_IDLEIMMEDIATE);
427
428         if (rq->errors >= ERROR_MAX) {
429                 ide_kill_rq(drive, rq);
430         } else {
431                 if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
432                         ++rq->errors;
433                         return ide_do_reset(drive);
434                 }
435                 ++rq->errors;
436         }
437
438         return ide_stopped;
439 }
440
441 ide_startstop_t
442 __ide_error(ide_drive_t *drive, struct request *rq, u8 stat, u8 err)
443 {
444         if (drive->media == ide_disk)
445                 return ide_ata_error(drive, rq, stat, err);
446         return ide_atapi_error(drive, rq, stat, err);
447 }
448
449 EXPORT_SYMBOL_GPL(__ide_error);
450
451 /**
452  *      ide_error       -       handle an error on the IDE
453  *      @drive: drive the error occurred on
454  *      @msg: message to report
455  *      @stat: status bits
456  *
457  *      ide_error() takes action based on the error returned by the drive.
458  *      For normal I/O that may well include retries. We deal with
459  *      both new-style (taskfile) and old style command handling here.
460  *      In the case of taskfile command handling there is work left to
461  *      do
462  */
463  
464 ide_startstop_t ide_error (ide_drive_t *drive, const char *msg, u8 stat)
465 {
466         struct request *rq;
467         u8 err;
468
469         err = ide_dump_status(drive, msg, stat);
470
471         if ((rq = HWGROUP(drive)->rq) == NULL)
472                 return ide_stopped;
473
474         /* retry only "normal" I/O: */
475         if (!blk_fs_request(rq)) {
476                 rq->errors = 1;
477                 ide_end_drive_cmd(drive, stat, err);
478                 return ide_stopped;
479         }
480
481         if (rq->rq_disk) {
482                 ide_driver_t *drv;
483
484                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
485                 return drv->error(drive, rq, stat, err);
486         } else
487                 return __ide_error(drive, rq, stat, err);
488 }
489
490 EXPORT_SYMBOL_GPL(ide_error);
491
492 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
493 {
494         tf->nsect   = drive->sect;
495         tf->lbal    = drive->sect;
496         tf->lbam    = drive->cyl;
497         tf->lbah    = drive->cyl >> 8;
498         tf->device  = (drive->head - 1) | drive->select;
499         tf->command = ATA_CMD_INIT_DEV_PARAMS;
500 }
501
502 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
503 {
504         tf->nsect   = drive->sect;
505         tf->command = ATA_CMD_RESTORE;
506 }
507
508 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
509 {
510         tf->nsect   = drive->mult_req;
511         tf->command = ATA_CMD_SET_MULTI;
512 }
513
514 static ide_startstop_t ide_disk_special(ide_drive_t *drive)
515 {
516         special_t *s = &drive->special;
517         ide_task_t args;
518
519         memset(&args, 0, sizeof(ide_task_t));
520         args.data_phase = TASKFILE_NO_DATA;
521
522         if (s->b.set_geometry) {
523                 s->b.set_geometry = 0;
524                 ide_tf_set_specify_cmd(drive, &args.tf);
525         } else if (s->b.recalibrate) {
526                 s->b.recalibrate = 0;
527                 ide_tf_set_restore_cmd(drive, &args.tf);
528         } else if (s->b.set_multmode) {
529                 s->b.set_multmode = 0;
530                 ide_tf_set_setmult_cmd(drive, &args.tf);
531         } else if (s->all) {
532                 int special = s->all;
533                 s->all = 0;
534                 printk(KERN_ERR "%s: bad special flag: 0x%02x\n", drive->name, special);
535                 return ide_stopped;
536         }
537
538         args.tf_flags = IDE_TFLAG_TF | IDE_TFLAG_DEVICE |
539                         IDE_TFLAG_CUSTOM_HANDLER;
540
541         do_rw_taskfile(drive, &args);
542
543         return ide_started;
544 }
545
546 /**
547  *      do_special              -       issue some special commands
548  *      @drive: drive the command is for
549  *
550  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
551  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
552  *
553  *      It used to do much more, but has been scaled back.
554  */
555
556 static ide_startstop_t do_special (ide_drive_t *drive)
557 {
558         special_t *s = &drive->special;
559
560 #ifdef DEBUG
561         printk("%s: do_special: 0x%02x\n", drive->name, s->all);
562 #endif
563         if (drive->media == ide_disk)
564                 return ide_disk_special(drive);
565
566         s->all = 0;
567         drive->mult_req = 0;
568         return ide_stopped;
569 }
570
571 void ide_map_sg(ide_drive_t *drive, struct request *rq)
572 {
573         ide_hwif_t *hwif = drive->hwif;
574         struct scatterlist *sg = hwif->sg_table;
575
576         if (hwif->sg_mapped)    /* needed by ide-scsi */
577                 return;
578
579         if (rq->cmd_type != REQ_TYPE_ATA_TASKFILE) {
580                 hwif->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
581         } else {
582                 sg_init_one(sg, rq->buffer, rq->nr_sectors * SECTOR_SIZE);
583                 hwif->sg_nents = 1;
584         }
585 }
586
587 EXPORT_SYMBOL_GPL(ide_map_sg);
588
589 void ide_init_sg_cmd(ide_drive_t *drive, struct request *rq)
590 {
591         ide_hwif_t *hwif = drive->hwif;
592
593         hwif->nsect = hwif->nleft = rq->nr_sectors;
594         hwif->cursg_ofs = 0;
595         hwif->cursg = NULL;
596 }
597
598 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
599
600 /**
601  *      execute_drive_command   -       issue special drive command
602  *      @drive: the drive to issue the command on
603  *      @rq: the request structure holding the command
604  *
605  *      execute_drive_cmd() issues a special drive command,  usually 
606  *      initiated by ioctl() from the external hdparm program. The
607  *      command can be a drive command, drive task or taskfile 
608  *      operation. Weirdly you can call it with NULL to wait for
609  *      all commands to finish. Don't do this as that is due to change
610  */
611
612 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
613                 struct request *rq)
614 {
615         ide_hwif_t *hwif = HWIF(drive);
616         ide_task_t *task = rq->special;
617
618         if (task) {
619                 hwif->data_phase = task->data_phase;
620
621                 switch (hwif->data_phase) {
622                 case TASKFILE_MULTI_OUT:
623                 case TASKFILE_OUT:
624                 case TASKFILE_MULTI_IN:
625                 case TASKFILE_IN:
626                         ide_init_sg_cmd(drive, rq);
627                         ide_map_sg(drive, rq);
628                 default:
629                         break;
630                 }
631
632                 return do_rw_taskfile(drive, task);
633         }
634
635         /*
636          * NULL is actually a valid way of waiting for
637          * all current requests to be flushed from the queue.
638          */
639 #ifdef DEBUG
640         printk("%s: DRIVE_CMD (null)\n", drive->name);
641 #endif
642         ide_end_drive_cmd(drive, hwif->tp_ops->read_status(hwif),
643                           ide_read_error(drive));
644
645         return ide_stopped;
646 }
647
648 int ide_devset_execute(ide_drive_t *drive, const struct ide_devset *setting,
649                        int arg)
650 {
651         struct request_queue *q = drive->queue;
652         struct request *rq;
653         int ret = 0;
654
655         if (!(setting->flags & DS_SYNC))
656                 return setting->set(drive, arg);
657
658         rq = blk_get_request(q, READ, __GFP_WAIT);
659         rq->cmd_type = REQ_TYPE_SPECIAL;
660         rq->cmd_len = 5;
661         rq->cmd[0] = REQ_DEVSET_EXEC;
662         *(int *)&rq->cmd[1] = arg;
663         rq->special = setting->set;
664
665         if (blk_execute_rq(q, NULL, rq, 0))
666                 ret = rq->errors;
667         blk_put_request(rq);
668
669         return ret;
670 }
671 EXPORT_SYMBOL_GPL(ide_devset_execute);
672
673 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
674 {
675         u8 cmd = rq->cmd[0];
676
677         if (cmd == REQ_PARK_HEADS || cmd == REQ_UNPARK_HEADS) {
678                 ide_task_t task;
679                 struct ide_taskfile *tf = &task.tf;
680
681                 memset(&task, 0, sizeof(task));
682                 if (cmd == REQ_PARK_HEADS) {
683                         drive->sleep = *(unsigned long *)rq->special;
684                         drive->dev_flags |= IDE_DFLAG_SLEEPING;
685                         tf->command = ATA_CMD_IDLEIMMEDIATE;
686                         tf->feature = 0x44;
687                         tf->lbal = 0x4c;
688                         tf->lbam = 0x4e;
689                         tf->lbah = 0x55;
690                         task.tf_flags |= IDE_TFLAG_CUSTOM_HANDLER;
691                 } else          /* cmd == REQ_UNPARK_HEADS */
692                         tf->command = ATA_CMD_CHK_POWER;
693
694                 task.tf_flags |= IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
695                 task.rq = rq;
696                 drive->hwif->data_phase = task.data_phase = TASKFILE_NO_DATA;
697                 return do_rw_taskfile(drive, &task);
698         }
699
700         switch (cmd) {
701         case REQ_DEVSET_EXEC:
702         {
703                 int err, (*setfunc)(ide_drive_t *, int) = rq->special;
704
705                 err = setfunc(drive, *(int *)&rq->cmd[1]);
706                 if (err)
707                         rq->errors = err;
708                 else
709                         err = 1;
710                 ide_end_request(drive, err, 0);
711                 return ide_stopped;
712         }
713         case REQ_DRIVE_RESET:
714                 return ide_do_reset(drive);
715         default:
716                 blk_dump_rq_flags(rq, "ide_special_rq - bad request");
717                 ide_end_request(drive, 0, 0);
718                 return ide_stopped;
719         }
720 }
721
722 static void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
723 {
724         struct request_pm_state *pm = rq->data;
725
726         if (blk_pm_suspend_request(rq) &&
727             pm->pm_step == IDE_PM_START_SUSPEND)
728                 /* Mark drive blocked when starting the suspend sequence. */
729                 drive->dev_flags |= IDE_DFLAG_BLOCKED;
730         else if (blk_pm_resume_request(rq) &&
731                  pm->pm_step == IDE_PM_START_RESUME) {
732                 /* 
733                  * The first thing we do on wakeup is to wait for BSY bit to
734                  * go away (with a looong timeout) as a drive on this hwif may
735                  * just be POSTing itself.
736                  * We do that before even selecting as the "other" device on
737                  * the bus may be broken enough to walk on our toes at this
738                  * point.
739                  */
740                 ide_hwif_t *hwif = drive->hwif;
741                 int rc;
742 #ifdef DEBUG_PM
743                 printk("%s: Wakeup request inited, waiting for !BSY...\n", drive->name);
744 #endif
745                 rc = ide_wait_not_busy(hwif, 35000);
746                 if (rc)
747                         printk(KERN_WARNING "%s: bus not ready on wakeup\n", drive->name);
748                 SELECT_DRIVE(drive);
749                 hwif->tp_ops->set_irq(hwif, 1);
750                 rc = ide_wait_not_busy(hwif, 100000);
751                 if (rc)
752                         printk(KERN_WARNING "%s: drive not ready on wakeup\n", drive->name);
753         }
754 }
755
756 /**
757  *      start_request   -       start of I/O and command issuing for IDE
758  *
759  *      start_request() initiates handling of a new I/O request. It
760  *      accepts commands and I/O (read/write) requests.
761  *
762  *      FIXME: this function needs a rename
763  */
764  
765 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
766 {
767         ide_startstop_t startstop;
768
769         BUG_ON(!blk_rq_started(rq));
770
771 #ifdef DEBUG
772         printk("%s: start_request: current=0x%08lx\n",
773                 HWIF(drive)->name, (unsigned long) rq);
774 #endif
775
776         /* bail early if we've exceeded max_failures */
777         if (drive->max_failures && (drive->failures > drive->max_failures)) {
778                 rq->cmd_flags |= REQ_FAILED;
779                 goto kill_rq;
780         }
781
782         if (blk_pm_request(rq))
783                 ide_check_pm_state(drive, rq);
784
785         SELECT_DRIVE(drive);
786         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
787                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
788                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
789                 return startstop;
790         }
791         if (!drive->special.all) {
792                 ide_driver_t *drv;
793
794                 /*
795                  * We reset the drive so we need to issue a SETFEATURES.
796                  * Do it _after_ do_special() restored device parameters.
797                  */
798                 if (drive->current_speed == 0xff)
799                         ide_config_drive_speed(drive, drive->desired_speed);
800
801                 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
802                         return execute_drive_cmd(drive, rq);
803                 else if (blk_pm_request(rq)) {
804                         struct request_pm_state *pm = rq->data;
805 #ifdef DEBUG_PM
806                         printk("%s: start_power_step(step: %d)\n",
807                                 drive->name, rq->pm->pm_step);
808 #endif
809                         startstop = ide_start_power_step(drive, rq);
810                         if (startstop == ide_stopped &&
811                             pm->pm_step == IDE_PM_COMPLETED)
812                                 ide_complete_pm_request(drive, rq);
813                         return startstop;
814                 } else if (!rq->rq_disk && blk_special_request(rq))
815                         /*
816                          * TODO: Once all ULDs have been modified to
817                          * check for specific op codes rather than
818                          * blindly accepting any special request, the
819                          * check for ->rq_disk above may be replaced
820                          * by a more suitable mechanism or even
821                          * dropped entirely.
822                          */
823                         return ide_special_rq(drive, rq);
824
825                 drv = *(ide_driver_t **)rq->rq_disk->private_data;
826
827                 return drv->do_request(drive, rq, rq->sector);
828         }
829         return do_special(drive);
830 kill_rq:
831         ide_kill_rq(drive, rq);
832         return ide_stopped;
833 }
834
835 /**
836  *      ide_stall_queue         -       pause an IDE device
837  *      @drive: drive to stall
838  *      @timeout: time to stall for (jiffies)
839  *
840  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
841  *      to the hwgroup by sleeping for timeout jiffies.
842  */
843  
844 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
845 {
846         if (timeout > WAIT_WORSTCASE)
847                 timeout = WAIT_WORSTCASE;
848         drive->sleep = timeout + jiffies;
849         drive->dev_flags |= IDE_DFLAG_SLEEPING;
850 }
851
852 EXPORT_SYMBOL(ide_stall_queue);
853
854 #define WAKEUP(drive)   ((drive)->service_start + 2 * (drive)->service_time)
855
856 /**
857  *      choose_drive            -       select a drive to service
858  *      @hwgroup: hardware group to select on
859  *
860  *      choose_drive() selects the next drive which will be serviced.
861  *      This is necessary because the IDE layer can't issue commands
862  *      to both drives on the same cable, unlike SCSI.
863  */
864  
865 static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
866 {
867         ide_drive_t *drive, *best;
868
869 repeat: 
870         best = NULL;
871         drive = hwgroup->drive;
872
873         /*
874          * drive is doing pre-flush, ordered write, post-flush sequence. even
875          * though that is 3 requests, it must be seen as a single transaction.
876          * we must not preempt this drive until that is complete
877          */
878         if (blk_queue_flushing(drive->queue)) {
879                 /*
880                  * small race where queue could get replugged during
881                  * the 3-request flush cycle, just yank the plug since
882                  * we want it to finish asap
883                  */
884                 blk_remove_plug(drive->queue);
885                 return drive;
886         }
887
888         do {
889                 u8 dev_s = !!(drive->dev_flags & IDE_DFLAG_SLEEPING);
890                 u8 best_s = (best && !!(best->dev_flags & IDE_DFLAG_SLEEPING));
891
892                 if ((dev_s == 0 || time_after_eq(jiffies, drive->sleep)) &&
893                     !elv_queue_empty(drive->queue)) {
894                         if (best == NULL ||
895                             (dev_s && (best_s == 0 || time_before(drive->sleep, best->sleep))) ||
896                             (best_s == 0 && time_before(WAKEUP(drive), WAKEUP(best)))) {
897                                 if (!blk_queue_plugged(drive->queue))
898                                         best = drive;
899                         }
900                 }
901         } while ((drive = drive->next) != hwgroup->drive);
902
903         if (best && (best->dev_flags & IDE_DFLAG_NICE1) &&
904             (best->dev_flags & IDE_DFLAG_SLEEPING) == 0 &&
905             best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
906                 long t = (signed long)(WAKEUP(best) - jiffies);
907                 if (t >= WAIT_MIN_SLEEP) {
908                 /*
909                  * We *may* have some time to spare, but first let's see if
910                  * someone can potentially benefit from our nice mood today..
911                  */
912                         drive = best->next;
913                         do {
914                                 if ((drive->dev_flags & IDE_DFLAG_SLEEPING) == 0
915                                  && time_before(jiffies - best->service_time, WAKEUP(drive))
916                                  && time_before(WAKEUP(drive), jiffies + t))
917                                 {
918                                         ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP));
919                                         goto repeat;
920                                 }
921                         } while ((drive = drive->next) != best);
922                 }
923         }
924         return best;
925 }
926
927 /*
928  * Issue a new request to a drive from hwgroup
929  * Caller must have already done spin_lock_irqsave(&ide_lock, ..);
930  *
931  * A hwgroup is a serialized group of IDE interfaces.  Usually there is
932  * exactly one hwif (interface) per hwgroup, but buggy controllers (eg. CMD640)
933  * may have both interfaces in a single hwgroup to "serialize" access.
934  * Or possibly multiple ISA interfaces can share a common IRQ by being grouped
935  * together into one hwgroup for serialized access.
936  *
937  * Note also that several hwgroups can end up sharing a single IRQ,
938  * possibly along with many other devices.  This is especially common in
939  * PCI-based systems with off-board IDE controller cards.
940  *
941  * The IDE driver uses the single global ide_lock spinlock to protect
942  * access to the request queues, and to protect the hwgroup->busy flag.
943  *
944  * The first thread into the driver for a particular hwgroup sets the
945  * hwgroup->busy flag to indicate that this hwgroup is now active,
946  * and then initiates processing of the top request from the request queue.
947  *
948  * Other threads attempting entry notice the busy setting, and will simply
949  * queue their new requests and exit immediately.  Note that hwgroup->busy
950  * remains set even when the driver is merely awaiting the next interrupt.
951  * Thus, the meaning is "this hwgroup is busy processing a request".
952  *
953  * When processing of a request completes, the completing thread or IRQ-handler
954  * will start the next request from the queue.  If no more work remains,
955  * the driver will clear the hwgroup->busy flag and exit.
956  *
957  * The ide_lock (spinlock) is used to protect all access to the
958  * hwgroup->busy flag, but is otherwise not needed for most processing in
959  * the driver.  This makes the driver much more friendlier to shared IRQs
960  * than previous designs, while remaining 100% (?) SMP safe and capable.
961  */
962 static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
963 {
964         ide_drive_t     *drive;
965         ide_hwif_t      *hwif;
966         struct request  *rq;
967         ide_startstop_t startstop;
968         int             loops = 0;
969
970         /* for atari only: POSSIBLY BROKEN HERE(?) */
971         ide_get_lock(ide_intr, hwgroup);
972
973         /* caller must own ide_lock */
974         BUG_ON(!irqs_disabled());
975
976         while (!hwgroup->busy) {
977                 hwgroup->busy = 1;
978                 drive = choose_drive(hwgroup);
979                 if (drive == NULL) {
980                         int sleeping = 0;
981                         unsigned long sleep = 0; /* shut up, gcc */
982                         hwgroup->rq = NULL;
983                         drive = hwgroup->drive;
984                         do {
985                                 if ((drive->dev_flags & IDE_DFLAG_SLEEPING) &&
986                                     (sleeping == 0 ||
987                                      time_before(drive->sleep, sleep))) {
988                                         sleeping = 1;
989                                         sleep = drive->sleep;
990                                 }
991                         } while ((drive = drive->next) != hwgroup->drive);
992                         if (sleeping) {
993                 /*
994                  * Take a short snooze, and then wake up this hwgroup again.
995                  * This gives other hwgroups on the same a chance to
996                  * play fairly with us, just in case there are big differences
997                  * in relative throughputs.. don't want to hog the cpu too much.
998                  */
999                                 if (time_before(sleep, jiffies + WAIT_MIN_SLEEP))
1000                                         sleep = jiffies + WAIT_MIN_SLEEP;
1001 #if 1
1002                                 if (timer_pending(&hwgroup->timer))
1003                                         printk(KERN_CRIT "ide_set_handler: timer already active\n");
1004 #endif
1005                                 /* so that ide_timer_expiry knows what to do */
1006                                 hwgroup->sleeping = 1;
1007                                 hwgroup->req_gen_timer = hwgroup->req_gen;
1008                                 mod_timer(&hwgroup->timer, sleep);
1009                                 /* we purposely leave hwgroup->busy==1
1010                                  * while sleeping */
1011                         } else {
1012                                 /* Ugly, but how can we sleep for the lock
1013                                  * otherwise? perhaps from tq_disk?
1014                                  */
1015
1016                                 /* for atari only */
1017                                 ide_release_lock();
1018                                 hwgroup->busy = 0;
1019                         }
1020
1021                         /* no more work for this hwgroup (for now) */
1022                         return;
1023                 }
1024         again:
1025                 hwif = HWIF(drive);
1026                 if (hwgroup->hwif->sharing_irq && hwif != hwgroup->hwif) {
1027                         /*
1028                          * set nIEN for previous hwif, drives in the
1029                          * quirk_list may not like intr setups/cleanups
1030                          */
1031                         if (drive->quirk_list != 1)
1032                                 hwif->tp_ops->set_irq(hwif, 0);
1033                 }
1034                 hwgroup->hwif = hwif;
1035                 hwgroup->drive = drive;
1036                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
1037                 drive->service_start = jiffies;
1038
1039                 if (blk_queue_plugged(drive->queue)) {
1040                         printk(KERN_ERR "ide: huh? queue was plugged!\n");
1041                         break;
1042                 }
1043
1044                 /*
1045                  * we know that the queue isn't empty, but this can happen
1046                  * if the q->prep_rq_fn() decides to kill a request
1047                  */
1048                 rq = elv_next_request(drive->queue);
1049                 if (!rq) {
1050                         hwgroup->busy = 0;
1051                         break;
1052                 }
1053
1054                 /*
1055                  * Sanity: don't accept a request that isn't a PM request
1056                  * if we are currently power managed. This is very important as
1057                  * blk_stop_queue() doesn't prevent the elv_next_request()
1058                  * above to return us whatever is in the queue. Since we call
1059                  * ide_do_request() ourselves, we end up taking requests while
1060                  * the queue is blocked...
1061                  * 
1062                  * We let requests forced at head of queue with ide-preempt
1063                  * though. I hope that doesn't happen too much, hopefully not
1064                  * unless the subdriver triggers such a thing in its own PM
1065                  * state machine.
1066                  *
1067                  * We count how many times we loop here to make sure we service
1068                  * all drives in the hwgroup without looping for ever
1069                  */
1070                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
1071                     blk_pm_request(rq) == 0 &&
1072                     (rq->cmd_flags & REQ_PREEMPT) == 0) {
1073                         drive = drive->next ? drive->next : hwgroup->drive;
1074                         if (loops++ < 4 && !blk_queue_plugged(drive->queue))
1075                                 goto again;
1076                         /* We clear busy, there should be no pending ATA command at this point. */
1077                         hwgroup->busy = 0;
1078                         break;
1079                 }
1080
1081                 hwgroup->rq = rq;
1082
1083                 /*
1084                  * Some systems have trouble with IDE IRQs arriving while
1085                  * the driver is still setting things up.  So, here we disable
1086                  * the IRQ used by this interface while the request is being started.
1087                  * This may look bad at first, but pretty much the same thing
1088                  * happens anyway when any interrupt comes in, IDE or otherwise
1089                  *  -- the kernel masks the IRQ while it is being handled.
1090                  */
1091                 if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
1092                         disable_irq_nosync(hwif->irq);
1093                 spin_unlock(&ide_lock);
1094                 local_irq_enable_in_hardirq();
1095                         /* allow other IRQs while we start this request */
1096                 startstop = start_request(drive, rq);
1097                 spin_lock_irq(&ide_lock);
1098                 if (masked_irq != IDE_NO_IRQ && hwif->irq != masked_irq)
1099                         enable_irq(hwif->irq);
1100                 if (startstop == ide_stopped)
1101                         hwgroup->busy = 0;
1102         }
1103 }
1104
1105 /*
1106  * Passes the stuff to ide_do_request
1107  */
1108 void do_ide_request(struct request_queue *q)
1109 {
1110         ide_drive_t *drive = q->queuedata;
1111
1112         ide_do_request(HWGROUP(drive), IDE_NO_IRQ);
1113 }
1114
1115 /*
1116  * un-busy the hwgroup etc, and clear any pending DMA status. we want to
1117  * retry the current request in pio mode instead of risking tossing it
1118  * all away
1119  */
1120 static ide_startstop_t ide_dma_timeout_retry(ide_drive_t *drive, int error)
1121 {
1122         ide_hwif_t *hwif = HWIF(drive);
1123         struct request *rq;
1124         ide_startstop_t ret = ide_stopped;
1125
1126         /*
1127          * end current dma transaction
1128          */
1129
1130         if (error < 0) {
1131                 printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
1132                 (void)hwif->dma_ops->dma_end(drive);
1133                 ret = ide_error(drive, "dma timeout error",
1134                                 hwif->tp_ops->read_status(hwif));
1135         } else {
1136                 printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
1137                 hwif->dma_ops->dma_timeout(drive);
1138         }
1139
1140         /*
1141          * disable dma for now, but remember that we did so because of
1142          * a timeout -- we'll reenable after we finish this next request
1143          * (or rather the first chunk of it) in pio.
1144          */
1145         drive->dev_flags |= IDE_DFLAG_DMA_PIO_RETRY;
1146         drive->retry_pio++;
1147         ide_dma_off_quietly(drive);
1148
1149         /*
1150          * un-busy drive etc (hwgroup->busy is cleared on return) and
1151          * make sure request is sane
1152          */
1153         rq = HWGROUP(drive)->rq;
1154
1155         if (!rq)
1156                 goto out;
1157
1158         HWGROUP(drive)->rq = NULL;
1159
1160         rq->errors = 0;
1161
1162         if (!rq->bio)
1163                 goto out;
1164
1165         rq->sector = rq->bio->bi_sector;
1166         rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9;
1167         rq->hard_cur_sectors = rq->current_nr_sectors;
1168         rq->buffer = bio_data(rq->bio);
1169 out:
1170         return ret;
1171 }
1172
1173 /**
1174  *      ide_timer_expiry        -       handle lack of an IDE interrupt
1175  *      @data: timer callback magic (hwgroup)
1176  *
1177  *      An IDE command has timed out before the expected drive return
1178  *      occurred. At this point we attempt to clean up the current
1179  *      mess. If the current handler includes an expiry handler then
1180  *      we invoke the expiry handler, and providing it is happy the
1181  *      work is done. If that fails we apply generic recovery rules
1182  *      invoking the handler and checking the drive DMA status. We
1183  *      have an excessively incestuous relationship with the DMA
1184  *      logic that wants cleaning up.
1185  */
1186  
1187 void ide_timer_expiry (unsigned long data)
1188 {
1189         ide_hwgroup_t   *hwgroup = (ide_hwgroup_t *) data;
1190         ide_handler_t   *handler;
1191         ide_expiry_t    *expiry;
1192         unsigned long   flags;
1193         unsigned long   wait = -1;
1194
1195         spin_lock_irqsave(&ide_lock, flags);
1196
1197         if (((handler = hwgroup->handler) == NULL) ||
1198             (hwgroup->req_gen != hwgroup->req_gen_timer)) {
1199                 /*
1200                  * Either a marginal timeout occurred
1201                  * (got the interrupt just as timer expired),
1202                  * or we were "sleeping" to give other devices a chance.
1203                  * Either way, we don't really want to complain about anything.
1204                  */
1205                 if (hwgroup->sleeping) {
1206                         hwgroup->sleeping = 0;
1207                         hwgroup->busy = 0;
1208                 }
1209         } else {
1210                 ide_drive_t *drive = hwgroup->drive;
1211                 if (!drive) {
1212                         printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
1213                         hwgroup->handler = NULL;
1214                 } else {
1215                         ide_hwif_t *hwif;
1216                         ide_startstop_t startstop = ide_stopped;
1217                         if (!hwgroup->busy) {
1218                                 hwgroup->busy = 1;      /* paranoia */
1219                                 printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name);
1220                         }
1221                         if ((expiry = hwgroup->expiry) != NULL) {
1222                                 /* continue */
1223                                 if ((wait = expiry(drive)) > 0) {
1224                                         /* reset timer */
1225                                         hwgroup->timer.expires  = jiffies + wait;
1226                                         hwgroup->req_gen_timer = hwgroup->req_gen;
1227                                         add_timer(&hwgroup->timer);
1228                                         spin_unlock_irqrestore(&ide_lock, flags);
1229                                         return;
1230                                 }
1231                         }
1232                         hwgroup->handler = NULL;
1233                         /*
1234                          * We need to simulate a real interrupt when invoking
1235                          * the handler() function, which means we need to
1236                          * globally mask the specific IRQ:
1237                          */
1238                         spin_unlock(&ide_lock);
1239                         hwif  = HWIF(drive);
1240                         /* disable_irq_nosync ?? */
1241                         disable_irq(hwif->irq);
1242                         /* local CPU only,
1243                          * as if we were handling an interrupt */
1244                         local_irq_disable();
1245                         if (hwgroup->polling) {
1246                                 startstop = handler(drive);
1247                         } else if (drive_is_ready(drive)) {
1248                                 if (drive->waiting_for_dma)
1249                                         hwif->dma_ops->dma_lost_irq(drive);
1250                                 (void)ide_ack_intr(hwif);
1251                                 printk(KERN_WARNING "%s: lost interrupt\n", drive->name);
1252                                 startstop = handler(drive);
1253                         } else {
1254                                 if (drive->waiting_for_dma) {
1255                                         startstop = ide_dma_timeout_retry(drive, wait);
1256                                 } else
1257                                         startstop =
1258                                         ide_error(drive, "irq timeout",
1259                                                   hwif->tp_ops->read_status(hwif));
1260                         }
1261                         drive->service_time = jiffies - drive->service_start;
1262                         spin_lock_irq(&ide_lock);
1263                         enable_irq(hwif->irq);
1264                         if (startstop == ide_stopped)
1265                                 hwgroup->busy = 0;
1266                 }
1267         }
1268         ide_do_request(hwgroup, IDE_NO_IRQ);
1269         spin_unlock_irqrestore(&ide_lock, flags);
1270 }
1271
1272 /**
1273  *      unexpected_intr         -       handle an unexpected IDE interrupt
1274  *      @irq: interrupt line
1275  *      @hwgroup: hwgroup being processed
1276  *
1277  *      There's nothing really useful we can do with an unexpected interrupt,
1278  *      other than reading the status register (to clear it), and logging it.
1279  *      There should be no way that an irq can happen before we're ready for it,
1280  *      so we needn't worry much about losing an "important" interrupt here.
1281  *
1282  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
1283  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
1284  *      looks "good", we just ignore the interrupt completely.
1285  *
1286  *      This routine assumes __cli() is in effect when called.
1287  *
1288  *      If an unexpected interrupt happens on irq15 while we are handling irq14
1289  *      and if the two interfaces are "serialized" (CMD640), then it looks like
1290  *      we could screw up by interfering with a new request being set up for 
1291  *      irq15.
1292  *
1293  *      In reality, this is a non-issue.  The new command is not sent unless 
1294  *      the drive is ready to accept one, in which case we know the drive is
1295  *      not trying to interrupt us.  And ide_set_handler() is always invoked
1296  *      before completing the issuance of any new drive command, so we will not
1297  *      be accidentally invoked as a result of any valid command completion
1298  *      interrupt.
1299  *
1300  *      Note that we must walk the entire hwgroup here. We know which hwif
1301  *      is doing the current command, but we don't know which hwif burped
1302  *      mysteriously.
1303  */
1304  
1305 static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
1306 {
1307         u8 stat;
1308         ide_hwif_t *hwif = hwgroup->hwif;
1309
1310         /*
1311          * handle the unexpected interrupt
1312          */
1313         do {
1314                 if (hwif->irq == irq) {
1315                         stat = hwif->tp_ops->read_status(hwif);
1316
1317                         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
1318                                 /* Try to not flood the console with msgs */
1319                                 static unsigned long last_msgtime, count;
1320                                 ++count;
1321                                 if (time_after(jiffies, last_msgtime + HZ)) {
1322                                         last_msgtime = jiffies;
1323                                         printk(KERN_ERR "%s%s: unexpected interrupt, "
1324                                                 "status=0x%02x, count=%ld\n",
1325                                                 hwif->name,
1326                                                 (hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count);
1327                                 }
1328                         }
1329                 }
1330         } while ((hwif = hwif->next) != hwgroup->hwif);
1331 }
1332
1333 /**
1334  *      ide_intr        -       default IDE interrupt handler
1335  *      @irq: interrupt number
1336  *      @dev_id: hwif group
1337  *      @regs: unused weirdness from the kernel irq layer
1338  *
1339  *      This is the default IRQ handler for the IDE layer. You should
1340  *      not need to override it. If you do be aware it is subtle in
1341  *      places
1342  *
1343  *      hwgroup->hwif is the interface in the group currently performing
1344  *      a command. hwgroup->drive is the drive and hwgroup->handler is
1345  *      the IRQ handler to call. As we issue a command the handlers
1346  *      step through multiple states, reassigning the handler to the
1347  *      next step in the process. Unlike a smart SCSI controller IDE
1348  *      expects the main processor to sequence the various transfer
1349  *      stages. We also manage a poll timer to catch up with most
1350  *      timeout situations. There are still a few where the handlers
1351  *      don't ever decide to give up.
1352  *
1353  *      The handler eventually returns ide_stopped to indicate the
1354  *      request completed. At this point we issue the next request
1355  *      on the hwgroup and the process begins again.
1356  */
1357  
1358 irqreturn_t ide_intr (int irq, void *dev_id)
1359 {
1360         unsigned long flags;
1361         ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
1362         ide_hwif_t *hwif;
1363         ide_drive_t *drive;
1364         ide_handler_t *handler;
1365         ide_startstop_t startstop;
1366
1367         spin_lock_irqsave(&ide_lock, flags);
1368         hwif = hwgroup->hwif;
1369
1370         if (!ide_ack_intr(hwif)) {
1371                 spin_unlock_irqrestore(&ide_lock, flags);
1372                 return IRQ_NONE;
1373         }
1374
1375         if ((handler = hwgroup->handler) == NULL || hwgroup->polling) {
1376                 /*
1377                  * Not expecting an interrupt from this drive.
1378                  * That means this could be:
1379                  *      (1) an interrupt from another PCI device
1380                  *      sharing the same PCI INT# as us.
1381                  * or   (2) a drive just entered sleep or standby mode,
1382                  *      and is interrupting to let us know.
1383                  * or   (3) a spurious interrupt of unknown origin.
1384                  *
1385                  * For PCI, we cannot tell the difference,
1386                  * so in that case we just ignore it and hope it goes away.
1387                  *
1388                  * FIXME: unexpected_intr should be hwif-> then we can
1389                  * remove all the ifdef PCI crap
1390                  */
1391 #ifdef CONFIG_BLK_DEV_IDEPCI
1392                 if (hwif->chipset != ide_pci)
1393 #endif  /* CONFIG_BLK_DEV_IDEPCI */
1394                 {
1395                         /*
1396                          * Probably not a shared PCI interrupt,
1397                          * so we can safely try to do something about it:
1398                          */
1399                         unexpected_intr(irq, hwgroup);
1400 #ifdef CONFIG_BLK_DEV_IDEPCI
1401                 } else {
1402                         /*
1403                          * Whack the status register, just in case
1404                          * we have a leftover pending IRQ.
1405                          */
1406                         (void)hwif->tp_ops->read_status(hwif);
1407 #endif /* CONFIG_BLK_DEV_IDEPCI */
1408                 }
1409                 spin_unlock_irqrestore(&ide_lock, flags);
1410                 return IRQ_NONE;
1411         }
1412         drive = hwgroup->drive;
1413         if (!drive) {
1414                 /*
1415                  * This should NEVER happen, and there isn't much
1416                  * we could do about it here.
1417                  *
1418                  * [Note - this can occur if the drive is hot unplugged]
1419                  */
1420                 spin_unlock_irqrestore(&ide_lock, flags);
1421                 return IRQ_HANDLED;
1422         }
1423         if (!drive_is_ready(drive)) {
1424                 /*
1425                  * This happens regularly when we share a PCI IRQ with
1426                  * another device.  Unfortunately, it can also happen
1427                  * with some buggy drives that trigger the IRQ before
1428                  * their status register is up to date.  Hopefully we have
1429                  * enough advance overhead that the latter isn't a problem.
1430                  */
1431                 spin_unlock_irqrestore(&ide_lock, flags);
1432                 return IRQ_NONE;
1433         }
1434         if (!hwgroup->busy) {
1435                 hwgroup->busy = 1;      /* paranoia */
1436                 printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name);
1437         }
1438         hwgroup->handler = NULL;
1439         hwgroup->req_gen++;
1440         del_timer(&hwgroup->timer);
1441         spin_unlock(&ide_lock);
1442
1443         if (hwif->port_ops && hwif->port_ops->clear_irq)
1444                 hwif->port_ops->clear_irq(drive);
1445
1446         if (drive->dev_flags & IDE_DFLAG_UNMASK)
1447                 local_irq_enable_in_hardirq();
1448
1449         /* service this interrupt, may set handler for next interrupt */
1450         startstop = handler(drive);
1451
1452         spin_lock_irq(&ide_lock);
1453         /*
1454          * Note that handler() may have set things up for another
1455          * interrupt to occur soon, but it cannot happen until
1456          * we exit from this routine, because it will be the
1457          * same irq as is currently being serviced here, and Linux
1458          * won't allow another of the same (on any CPU) until we return.
1459          */
1460         drive->service_time = jiffies - drive->service_start;
1461         if (startstop == ide_stopped) {
1462                 if (hwgroup->handler == NULL) { /* paranoia */
1463                         hwgroup->busy = 0;
1464                         ide_do_request(hwgroup, hwif->irq);
1465                 } else {
1466                         printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler "
1467                                 "on exit\n", drive->name);
1468                 }
1469         }
1470         spin_unlock_irqrestore(&ide_lock, flags);
1471         return IRQ_HANDLED;
1472 }
1473
1474 /**
1475  *      ide_do_drive_cmd        -       issue IDE special command
1476  *      @drive: device to issue command
1477  *      @rq: request to issue
1478  *
1479  *      This function issues a special IDE device request
1480  *      onto the request queue.
1481  *
1482  *      the rq is queued at the head of the request queue, displacing
1483  *      the currently-being-processed request and this function
1484  *      returns immediately without waiting for the new rq to be
1485  *      completed.  This is VERY DANGEROUS, and is intended for
1486  *      careful use by the ATAPI tape/cdrom driver code.
1487  */
1488
1489 void ide_do_drive_cmd(ide_drive_t *drive, struct request *rq)
1490 {
1491         unsigned long flags;
1492         ide_hwgroup_t *hwgroup = HWGROUP(drive);
1493
1494         spin_lock_irqsave(&ide_lock, flags);
1495         hwgroup->rq = NULL;
1496         __elv_add_request(drive->queue, rq, ELEVATOR_INSERT_FRONT, 0);
1497         blk_start_queueing(drive->queue);
1498         spin_unlock_irqrestore(&ide_lock, flags);
1499 }
1500
1501 EXPORT_SYMBOL(ide_do_drive_cmd);
1502
1503 void ide_pktcmd_tf_load(ide_drive_t *drive, u32 tf_flags, u16 bcount, u8 dma)
1504 {
1505         ide_hwif_t *hwif = drive->hwif;
1506         ide_task_t task;
1507
1508         memset(&task, 0, sizeof(task));
1509         task.tf_flags = IDE_TFLAG_OUT_LBAH | IDE_TFLAG_OUT_LBAM |
1510                         IDE_TFLAG_OUT_FEATURE | tf_flags;
1511         task.tf.feature = dma;          /* Use PIO/DMA */
1512         task.tf.lbam    = bcount & 0xff;
1513         task.tf.lbah    = (bcount >> 8) & 0xff;
1514
1515         ide_tf_dump(drive->name, &task.tf);
1516         hwif->tp_ops->set_irq(hwif, 1);
1517         SELECT_MASK(drive, 0);
1518         hwif->tp_ops->tf_load(drive, &task);
1519 }
1520
1521 EXPORT_SYMBOL_GPL(ide_pktcmd_tf_load);
1522
1523 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
1524 {
1525         ide_hwif_t *hwif = drive->hwif;
1526         u8 buf[4] = { 0 };
1527
1528         while (len > 0) {
1529                 if (write)
1530                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
1531                 else
1532                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
1533                 len -= 4;
1534         }
1535 }
1536 EXPORT_SYMBOL_GPL(ide_pad_transfer);