i2c: tegra: remove support for I2C_M_REV_DIR_ADDR
[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/completion.h>
44 #include <linux/reboot.h>
45 #include <linux/cdrom.h>
46 #include <linux/seq_file.h>
47 #include <linux/device.h>
48 #include <linux/kmod.h>
49 #include <linux/scatterlist.h>
50 #include <linux/bitops.h>
51
52 #include <asm/byteorder.h>
53 #include <asm/irq.h>
54 #include <asm/uaccess.h>
55 #include <asm/io.h>
56
57 int ide_end_rq(ide_drive_t *drive, struct request *rq, int error,
58                unsigned int nr_bytes)
59 {
60         /*
61          * decide whether to reenable DMA -- 3 is a random magic for now,
62          * if we DMA timeout more than 3 times, just stay in PIO
63          */
64         if ((drive->dev_flags & IDE_DFLAG_DMA_PIO_RETRY) &&
65             drive->retry_pio <= 3) {
66                 drive->dev_flags &= ~IDE_DFLAG_DMA_PIO_RETRY;
67                 ide_dma_on(drive);
68         }
69
70         return blk_end_request(rq, error, nr_bytes);
71 }
72 EXPORT_SYMBOL_GPL(ide_end_rq);
73
74 void ide_complete_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat, u8 err)
75 {
76         const struct ide_tp_ops *tp_ops = drive->hwif->tp_ops;
77         struct ide_taskfile *tf = &cmd->tf;
78         struct request *rq = cmd->rq;
79         u8 tf_cmd = tf->command;
80
81         tf->error = err;
82         tf->status = stat;
83
84         if (cmd->ftf_flags & IDE_FTFLAG_IN_DATA) {
85                 u8 data[2];
86
87                 tp_ops->input_data(drive, cmd, data, 2);
88
89                 cmd->tf.data  = data[0];
90                 cmd->hob.data = data[1];
91         }
92
93         ide_tf_readback(drive, cmd);
94
95         if ((cmd->tf_flags & IDE_TFLAG_CUSTOM_HANDLER) &&
96             tf_cmd == ATA_CMD_IDLEIMMEDIATE) {
97                 if (tf->lbal != 0xc4) {
98                         printk(KERN_ERR "%s: head unload failed!\n",
99                                drive->name);
100                         ide_tf_dump(drive->name, cmd);
101                 } else
102                         drive->dev_flags |= IDE_DFLAG_PARKED;
103         }
104
105         if (rq && rq->cmd_type == REQ_TYPE_ATA_TASKFILE) {
106                 struct ide_cmd *orig_cmd = rq->special;
107
108                 if (cmd->tf_flags & IDE_TFLAG_DYN)
109                         kfree(orig_cmd);
110                 else
111                         memcpy(orig_cmd, cmd, sizeof(*cmd));
112         }
113 }
114
115 int ide_complete_rq(ide_drive_t *drive, int error, unsigned int nr_bytes)
116 {
117         ide_hwif_t *hwif = drive->hwif;
118         struct request *rq = hwif->rq;
119         int rc;
120
121         /*
122          * if failfast is set on a request, override number of sectors
123          * and complete the whole request right now
124          */
125         if (blk_noretry_request(rq) && error <= 0)
126                 nr_bytes = blk_rq_sectors(rq) << 9;
127
128         rc = ide_end_rq(drive, rq, error, nr_bytes);
129         if (rc == 0)
130                 hwif->rq = NULL;
131
132         return rc;
133 }
134 EXPORT_SYMBOL(ide_complete_rq);
135
136 void ide_kill_rq(ide_drive_t *drive, struct request *rq)
137 {
138         u8 drv_req = (rq->cmd_type == REQ_TYPE_SPECIAL) && rq->rq_disk;
139         u8 media = drive->media;
140
141         drive->failed_pc = NULL;
142
143         if ((media == ide_floppy || media == ide_tape) && drv_req) {
144                 rq->errors = 0;
145         } else {
146                 if (media == ide_tape)
147                         rq->errors = IDE_DRV_ERROR_GENERAL;
148                 else if (rq->cmd_type != REQ_TYPE_FS && rq->errors == 0)
149                         rq->errors = -EIO;
150         }
151
152         ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
153 }
154
155 static void ide_tf_set_specify_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
156 {
157         tf->nsect   = drive->sect;
158         tf->lbal    = drive->sect;
159         tf->lbam    = drive->cyl;
160         tf->lbah    = drive->cyl >> 8;
161         tf->device  = (drive->head - 1) | drive->select;
162         tf->command = ATA_CMD_INIT_DEV_PARAMS;
163 }
164
165 static void ide_tf_set_restore_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
166 {
167         tf->nsect   = drive->sect;
168         tf->command = ATA_CMD_RESTORE;
169 }
170
171 static void ide_tf_set_setmult_cmd(ide_drive_t *drive, struct ide_taskfile *tf)
172 {
173         tf->nsect   = drive->mult_req;
174         tf->command = ATA_CMD_SET_MULTI;
175 }
176
177 /**
178  *      do_special              -       issue some special commands
179  *      @drive: drive the command is for
180  *
181  *      do_special() is used to issue ATA_CMD_INIT_DEV_PARAMS,
182  *      ATA_CMD_RESTORE and ATA_CMD_SET_MULTI commands to a drive.
183  */
184
185 static ide_startstop_t do_special(ide_drive_t *drive)
186 {
187         struct ide_cmd cmd;
188
189 #ifdef DEBUG
190         printk(KERN_DEBUG "%s: %s: 0x%02x\n", drive->name, __func__,
191                 drive->special_flags);
192 #endif
193         if (drive->media != ide_disk) {
194                 drive->special_flags = 0;
195                 drive->mult_req = 0;
196                 return ide_stopped;
197         }
198
199         memset(&cmd, 0, sizeof(cmd));
200         cmd.protocol = ATA_PROT_NODATA;
201
202         if (drive->special_flags & IDE_SFLAG_SET_GEOMETRY) {
203                 drive->special_flags &= ~IDE_SFLAG_SET_GEOMETRY;
204                 ide_tf_set_specify_cmd(drive, &cmd.tf);
205         } else if (drive->special_flags & IDE_SFLAG_RECALIBRATE) {
206                 drive->special_flags &= ~IDE_SFLAG_RECALIBRATE;
207                 ide_tf_set_restore_cmd(drive, &cmd.tf);
208         } else if (drive->special_flags & IDE_SFLAG_SET_MULTMODE) {
209                 drive->special_flags &= ~IDE_SFLAG_SET_MULTMODE;
210                 ide_tf_set_setmult_cmd(drive, &cmd.tf);
211         } else
212                 BUG();
213
214         cmd.valid.out.tf = IDE_VALID_OUT_TF | IDE_VALID_DEVICE;
215         cmd.valid.in.tf  = IDE_VALID_IN_TF  | IDE_VALID_DEVICE;
216         cmd.tf_flags = IDE_TFLAG_CUSTOM_HANDLER;
217
218         do_rw_taskfile(drive, &cmd);
219
220         return ide_started;
221 }
222
223 void ide_map_sg(ide_drive_t *drive, struct ide_cmd *cmd)
224 {
225         ide_hwif_t *hwif = drive->hwif;
226         struct scatterlist *sg = hwif->sg_table;
227         struct request *rq = cmd->rq;
228
229         cmd->sg_nents = blk_rq_map_sg(drive->queue, rq, sg);
230 }
231 EXPORT_SYMBOL_GPL(ide_map_sg);
232
233 void ide_init_sg_cmd(struct ide_cmd *cmd, unsigned int nr_bytes)
234 {
235         cmd->nbytes = cmd->nleft = nr_bytes;
236         cmd->cursg_ofs = 0;
237         cmd->cursg = NULL;
238 }
239 EXPORT_SYMBOL_GPL(ide_init_sg_cmd);
240
241 /**
242  *      execute_drive_command   -       issue special drive command
243  *      @drive: the drive to issue the command on
244  *      @rq: the request structure holding the command
245  *
246  *      execute_drive_cmd() issues a special drive command,  usually 
247  *      initiated by ioctl() from the external hdparm program. The
248  *      command can be a drive command, drive task or taskfile 
249  *      operation. Weirdly you can call it with NULL to wait for
250  *      all commands to finish. Don't do this as that is due to change
251  */
252
253 static ide_startstop_t execute_drive_cmd (ide_drive_t *drive,
254                 struct request *rq)
255 {
256         struct ide_cmd *cmd = rq->special;
257
258         if (cmd) {
259                 if (cmd->protocol == ATA_PROT_PIO) {
260                         ide_init_sg_cmd(cmd, blk_rq_sectors(rq) << 9);
261                         ide_map_sg(drive, cmd);
262                 }
263
264                 return do_rw_taskfile(drive, cmd);
265         }
266
267         /*
268          * NULL is actually a valid way of waiting for
269          * all current requests to be flushed from the queue.
270          */
271 #ifdef DEBUG
272         printk("%s: DRIVE_CMD (null)\n", drive->name);
273 #endif
274         rq->errors = 0;
275         ide_complete_rq(drive, 0, blk_rq_bytes(rq));
276
277         return ide_stopped;
278 }
279
280 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
281 {
282         u8 cmd = rq->cmd[0];
283
284         switch (cmd) {
285         case REQ_PARK_HEADS:
286         case REQ_UNPARK_HEADS:
287                 return ide_do_park_unpark(drive, rq);
288         case REQ_DEVSET_EXEC:
289                 return ide_do_devset(drive, rq);
290         case REQ_DRIVE_RESET:
291                 return ide_do_reset(drive);
292         default:
293                 BUG();
294         }
295 }
296
297 /**
298  *      start_request   -       start of I/O and command issuing for IDE
299  *
300  *      start_request() initiates handling of a new I/O request. It
301  *      accepts commands and I/O (read/write) requests.
302  *
303  *      FIXME: this function needs a rename
304  */
305  
306 static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
307 {
308         ide_startstop_t startstop;
309
310         BUG_ON(!(rq->cmd_flags & REQ_STARTED));
311
312 #ifdef DEBUG
313         printk("%s: start_request: current=0x%08lx\n",
314                 drive->hwif->name, (unsigned long) rq);
315 #endif
316
317         /* bail early if we've exceeded max_failures */
318         if (drive->max_failures && (drive->failures > drive->max_failures)) {
319                 rq->cmd_flags |= REQ_FAILED;
320                 goto kill_rq;
321         }
322
323         if (blk_pm_request(rq))
324                 ide_check_pm_state(drive, rq);
325
326         drive->hwif->tp_ops->dev_select(drive);
327         if (ide_wait_stat(&startstop, drive, drive->ready_stat,
328                           ATA_BUSY | ATA_DRQ, WAIT_READY)) {
329                 printk(KERN_ERR "%s: drive not ready for command\n", drive->name);
330                 return startstop;
331         }
332
333         if (drive->special_flags == 0) {
334                 struct ide_driver *drv;
335
336                 /*
337                  * We reset the drive so we need to issue a SETFEATURES.
338                  * Do it _after_ do_special() restored device parameters.
339                  */
340                 if (drive->current_speed == 0xff)
341                         ide_config_drive_speed(drive, drive->desired_speed);
342
343                 if (rq->cmd_type == REQ_TYPE_ATA_TASKFILE)
344                         return execute_drive_cmd(drive, rq);
345                 else if (blk_pm_request(rq)) {
346                         struct request_pm_state *pm = rq->special;
347 #ifdef DEBUG_PM
348                         printk("%s: start_power_step(step: %d)\n",
349                                 drive->name, pm->pm_step);
350 #endif
351                         startstop = ide_start_power_step(drive, rq);
352                         if (startstop == ide_stopped &&
353                             pm->pm_step == IDE_PM_COMPLETED)
354                                 ide_complete_pm_rq(drive, rq);
355                         return startstop;
356                 } else if (!rq->rq_disk && rq->cmd_type == REQ_TYPE_SPECIAL)
357                         /*
358                          * TODO: Once all ULDs have been modified to
359                          * check for specific op codes rather than
360                          * blindly accepting any special request, the
361                          * check for ->rq_disk above may be replaced
362                          * by a more suitable mechanism or even
363                          * dropped entirely.
364                          */
365                         return ide_special_rq(drive, rq);
366
367                 drv = *(struct ide_driver **)rq->rq_disk->private_data;
368
369                 return drv->do_request(drive, rq, blk_rq_pos(rq));
370         }
371         return do_special(drive);
372 kill_rq:
373         ide_kill_rq(drive, rq);
374         return ide_stopped;
375 }
376
377 /**
378  *      ide_stall_queue         -       pause an IDE device
379  *      @drive: drive to stall
380  *      @timeout: time to stall for (jiffies)
381  *
382  *      ide_stall_queue() can be used by a drive to give excess bandwidth back
383  *      to the port by sleeping for timeout jiffies.
384  */
385  
386 void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
387 {
388         if (timeout > WAIT_WORSTCASE)
389                 timeout = WAIT_WORSTCASE;
390         drive->sleep = timeout + jiffies;
391         drive->dev_flags |= IDE_DFLAG_SLEEPING;
392 }
393 EXPORT_SYMBOL(ide_stall_queue);
394
395 static inline int ide_lock_port(ide_hwif_t *hwif)
396 {
397         if (hwif->busy)
398                 return 1;
399
400         hwif->busy = 1;
401
402         return 0;
403 }
404
405 static inline void ide_unlock_port(ide_hwif_t *hwif)
406 {
407         hwif->busy = 0;
408 }
409
410 static inline int ide_lock_host(struct ide_host *host, ide_hwif_t *hwif)
411 {
412         int rc = 0;
413
414         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
415                 rc = test_and_set_bit_lock(IDE_HOST_BUSY, &host->host_busy);
416                 if (rc == 0) {
417                         if (host->get_lock)
418                                 host->get_lock(ide_intr, hwif);
419                 }
420         }
421         return rc;
422 }
423
424 static inline void ide_unlock_host(struct ide_host *host)
425 {
426         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
427                 if (host->release_lock)
428                         host->release_lock();
429                 clear_bit_unlock(IDE_HOST_BUSY, &host->host_busy);
430         }
431 }
432
433 static void __ide_requeue_and_plug(struct request_queue *q, struct request *rq)
434 {
435         if (rq)
436                 blk_requeue_request(q, rq);
437         if (rq || blk_peek_request(q)) {
438                 /* Use 3ms as that was the old plug delay */
439                 blk_delay_queue(q, 3);
440         }
441 }
442
443 void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
444 {
445         struct request_queue *q = drive->queue;
446         unsigned long flags;
447
448         spin_lock_irqsave(q->queue_lock, flags);
449         __ide_requeue_and_plug(q, rq);
450         spin_unlock_irqrestore(q->queue_lock, flags);
451 }
452
453 /*
454  * Issue a new request to a device.
455  */
456 void do_ide_request(struct request_queue *q)
457 {
458         ide_drive_t     *drive = q->queuedata;
459         ide_hwif_t      *hwif = drive->hwif;
460         struct ide_host *host = hwif->host;
461         struct request  *rq = NULL;
462         ide_startstop_t startstop;
463         unsigned long queue_run_ms = 3; /* old plug delay */
464
465         spin_unlock_irq(q->queue_lock);
466
467         /* HLD do_request() callback might sleep, make sure it's okay */
468         might_sleep();
469
470         if (ide_lock_host(host, hwif))
471                 goto plug_device_2;
472
473         spin_lock_irq(&hwif->lock);
474
475         if (!ide_lock_port(hwif)) {
476                 ide_hwif_t *prev_port;
477
478                 WARN_ON_ONCE(hwif->rq);
479 repeat:
480                 prev_port = hwif->host->cur_port;
481                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
482                     time_after(drive->sleep, jiffies)) {
483                         unsigned long left = jiffies - drive->sleep;
484
485                         queue_run_ms = jiffies_to_msecs(left + 1);
486                         ide_unlock_port(hwif);
487                         goto plug_device;
488                 }
489
490                 if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
491                     hwif != prev_port) {
492                         ide_drive_t *cur_dev =
493                                 prev_port ? prev_port->cur_dev : NULL;
494
495                         /*
496                          * set nIEN for previous port, drives in the
497                          * quirk list may not like intr setups/cleanups
498                          */
499                         if (cur_dev &&
500                             (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
501                                 prev_port->tp_ops->write_devctl(prev_port,
502                                                                 ATA_NIEN |
503                                                                 ATA_DEVCTL_OBS);
504
505                         hwif->host->cur_port = hwif;
506                 }
507                 hwif->cur_dev = drive;
508                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
509
510                 spin_unlock_irq(&hwif->lock);
511                 spin_lock_irq(q->queue_lock);
512                 /*
513                  * we know that the queue isn't empty, but this can happen
514                  * if the q->prep_rq_fn() decides to kill a request
515                  */
516                 if (!rq)
517                         rq = blk_fetch_request(drive->queue);
518
519                 spin_unlock_irq(q->queue_lock);
520                 spin_lock_irq(&hwif->lock);
521
522                 if (!rq) {
523                         ide_unlock_port(hwif);
524                         goto out;
525                 }
526
527                 /*
528                  * Sanity: don't accept a request that isn't a PM request
529                  * if we are currently power managed. This is very important as
530                  * blk_stop_queue() doesn't prevent the blk_fetch_request()
531                  * above to return us whatever is in the queue. Since we call
532                  * ide_do_request() ourselves, we end up taking requests while
533                  * the queue is blocked...
534                  * 
535                  * We let requests forced at head of queue with ide-preempt
536                  * though. I hope that doesn't happen too much, hopefully not
537                  * unless the subdriver triggers such a thing in its own PM
538                  * state machine.
539                  */
540                 if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
541                     blk_pm_request(rq) == 0 &&
542                     (rq->cmd_flags & REQ_PREEMPT) == 0) {
543                         /* there should be no pending command at this point */
544                         ide_unlock_port(hwif);
545                         goto plug_device;
546                 }
547
548                 hwif->rq = rq;
549
550                 spin_unlock_irq(&hwif->lock);
551                 startstop = start_request(drive, rq);
552                 spin_lock_irq(&hwif->lock);
553
554                 if (startstop == ide_stopped) {
555                         rq = hwif->rq;
556                         hwif->rq = NULL;
557                         goto repeat;
558                 }
559         } else
560                 goto plug_device;
561 out:
562         spin_unlock_irq(&hwif->lock);
563         if (rq == NULL)
564                 ide_unlock_host(host);
565         spin_lock_irq(q->queue_lock);
566         return;
567
568 plug_device:
569         spin_unlock_irq(&hwif->lock);
570         ide_unlock_host(host);
571 plug_device_2:
572         spin_lock_irq(q->queue_lock);
573         __ide_requeue_and_plug(q, rq);
574 }
575
576 static int drive_is_ready(ide_drive_t *drive)
577 {
578         ide_hwif_t *hwif = drive->hwif;
579         u8 stat = 0;
580
581         if (drive->waiting_for_dma)
582                 return hwif->dma_ops->dma_test_irq(drive);
583
584         if (hwif->io_ports.ctl_addr &&
585             (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
586                 stat = hwif->tp_ops->read_altstatus(hwif);
587         else
588                 /* Note: this may clear a pending IRQ!! */
589                 stat = hwif->tp_ops->read_status(hwif);
590
591         if (stat & ATA_BUSY)
592                 /* drive busy: definitely not interrupting */
593                 return 0;
594
595         /* drive ready: *might* be interrupting */
596         return 1;
597 }
598
599 /**
600  *      ide_timer_expiry        -       handle lack of an IDE interrupt
601  *      @data: timer callback magic (hwif)
602  *
603  *      An IDE command has timed out before the expected drive return
604  *      occurred. At this point we attempt to clean up the current
605  *      mess. If the current handler includes an expiry handler then
606  *      we invoke the expiry handler, and providing it is happy the
607  *      work is done. If that fails we apply generic recovery rules
608  *      invoking the handler and checking the drive DMA status. We
609  *      have an excessively incestuous relationship with the DMA
610  *      logic that wants cleaning up.
611  */
612  
613 void ide_timer_expiry (unsigned long data)
614 {
615         ide_hwif_t      *hwif = (ide_hwif_t *)data;
616         ide_drive_t     *uninitialized_var(drive);
617         ide_handler_t   *handler;
618         unsigned long   flags;
619         int             wait = -1;
620         int             plug_device = 0;
621         struct request  *uninitialized_var(rq_in_flight);
622
623         spin_lock_irqsave(&hwif->lock, flags);
624
625         handler = hwif->handler;
626
627         if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
628                 /*
629                  * Either a marginal timeout occurred
630                  * (got the interrupt just as timer expired),
631                  * or we were "sleeping" to give other devices a chance.
632                  * Either way, we don't really want to complain about anything.
633                  */
634         } else {
635                 ide_expiry_t *expiry = hwif->expiry;
636                 ide_startstop_t startstop = ide_stopped;
637
638                 drive = hwif->cur_dev;
639
640                 if (expiry) {
641                         wait = expiry(drive);
642                         if (wait > 0) { /* continue */
643                                 /* reset timer */
644                                 hwif->timer.expires = jiffies + wait;
645                                 hwif->req_gen_timer = hwif->req_gen;
646                                 add_timer(&hwif->timer);
647                                 spin_unlock_irqrestore(&hwif->lock, flags);
648                                 return;
649                         }
650                 }
651                 hwif->handler = NULL;
652                 hwif->expiry = NULL;
653                 /*
654                  * We need to simulate a real interrupt when invoking
655                  * the handler() function, which means we need to
656                  * globally mask the specific IRQ:
657                  */
658                 spin_unlock(&hwif->lock);
659                 /* disable_irq_nosync ?? */
660                 disable_irq(hwif->irq);
661                 /* local CPU only, as if we were handling an interrupt */
662                 local_irq_disable();
663                 if (hwif->polling) {
664                         startstop = handler(drive);
665                 } else if (drive_is_ready(drive)) {
666                         if (drive->waiting_for_dma)
667                                 hwif->dma_ops->dma_lost_irq(drive);
668                         if (hwif->port_ops && hwif->port_ops->clear_irq)
669                                 hwif->port_ops->clear_irq(drive);
670
671                         printk(KERN_WARNING "%s: lost interrupt\n",
672                                 drive->name);
673                         startstop = handler(drive);
674                 } else {
675                         if (drive->waiting_for_dma)
676                                 startstop = ide_dma_timeout_retry(drive, wait);
677                         else
678                                 startstop = ide_error(drive, "irq timeout",
679                                         hwif->tp_ops->read_status(hwif));
680                 }
681                 spin_lock_irq(&hwif->lock);
682                 enable_irq(hwif->irq);
683                 if (startstop == ide_stopped && hwif->polling == 0) {
684                         rq_in_flight = hwif->rq;
685                         hwif->rq = NULL;
686                         ide_unlock_port(hwif);
687                         plug_device = 1;
688                 }
689         }
690         spin_unlock_irqrestore(&hwif->lock, flags);
691
692         if (plug_device) {
693                 ide_unlock_host(hwif->host);
694                 ide_requeue_and_plug(drive, rq_in_flight);
695         }
696 }
697
698 /**
699  *      unexpected_intr         -       handle an unexpected IDE interrupt
700  *      @irq: interrupt line
701  *      @hwif: port being processed
702  *
703  *      There's nothing really useful we can do with an unexpected interrupt,
704  *      other than reading the status register (to clear it), and logging it.
705  *      There should be no way that an irq can happen before we're ready for it,
706  *      so we needn't worry much about losing an "important" interrupt here.
707  *
708  *      On laptops (and "green" PCs), an unexpected interrupt occurs whenever
709  *      the drive enters "idle", "standby", or "sleep" mode, so if the status
710  *      looks "good", we just ignore the interrupt completely.
711  *
712  *      This routine assumes __cli() is in effect when called.
713  *
714  *      If an unexpected interrupt happens on irq15 while we are handling irq14
715  *      and if the two interfaces are "serialized" (CMD640), then it looks like
716  *      we could screw up by interfering with a new request being set up for 
717  *      irq15.
718  *
719  *      In reality, this is a non-issue.  The new command is not sent unless 
720  *      the drive is ready to accept one, in which case we know the drive is
721  *      not trying to interrupt us.  And ide_set_handler() is always invoked
722  *      before completing the issuance of any new drive command, so we will not
723  *      be accidentally invoked as a result of any valid command completion
724  *      interrupt.
725  */
726
727 static void unexpected_intr(int irq, ide_hwif_t *hwif)
728 {
729         u8 stat = hwif->tp_ops->read_status(hwif);
730
731         if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
732                 /* Try to not flood the console with msgs */
733                 static unsigned long last_msgtime, count;
734                 ++count;
735
736                 if (time_after(jiffies, last_msgtime + HZ)) {
737                         last_msgtime = jiffies;
738                         printk(KERN_ERR "%s: unexpected interrupt, "
739                                 "status=0x%02x, count=%ld\n",
740                                 hwif->name, stat, count);
741                 }
742         }
743 }
744
745 /**
746  *      ide_intr        -       default IDE interrupt handler
747  *      @irq: interrupt number
748  *      @dev_id: hwif
749  *      @regs: unused weirdness from the kernel irq layer
750  *
751  *      This is the default IRQ handler for the IDE layer. You should
752  *      not need to override it. If you do be aware it is subtle in
753  *      places
754  *
755  *      hwif is the interface in the group currently performing
756  *      a command. hwif->cur_dev is the drive and hwif->handler is
757  *      the IRQ handler to call. As we issue a command the handlers
758  *      step through multiple states, reassigning the handler to the
759  *      next step in the process. Unlike a smart SCSI controller IDE
760  *      expects the main processor to sequence the various transfer
761  *      stages. We also manage a poll timer to catch up with most
762  *      timeout situations. There are still a few where the handlers
763  *      don't ever decide to give up.
764  *
765  *      The handler eventually returns ide_stopped to indicate the
766  *      request completed. At this point we issue the next request
767  *      on the port and the process begins again.
768  */
769
770 irqreturn_t ide_intr (int irq, void *dev_id)
771 {
772         ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
773         struct ide_host *host = hwif->host;
774         ide_drive_t *uninitialized_var(drive);
775         ide_handler_t *handler;
776         unsigned long flags;
777         ide_startstop_t startstop;
778         irqreturn_t irq_ret = IRQ_NONE;
779         int plug_device = 0;
780         struct request *uninitialized_var(rq_in_flight);
781
782         if (host->host_flags & IDE_HFLAG_SERIALIZE) {
783                 if (hwif != host->cur_port)
784                         goto out_early;
785         }
786
787         spin_lock_irqsave(&hwif->lock, flags);
788
789         if (hwif->port_ops && hwif->port_ops->test_irq &&
790             hwif->port_ops->test_irq(hwif) == 0)
791                 goto out;
792
793         handler = hwif->handler;
794
795         if (handler == NULL || hwif->polling) {
796                 /*
797                  * Not expecting an interrupt from this drive.
798                  * That means this could be:
799                  *      (1) an interrupt from another PCI device
800                  *      sharing the same PCI INT# as us.
801                  * or   (2) a drive just entered sleep or standby mode,
802                  *      and is interrupting to let us know.
803                  * or   (3) a spurious interrupt of unknown origin.
804                  *
805                  * For PCI, we cannot tell the difference,
806                  * so in that case we just ignore it and hope it goes away.
807                  */
808                 if ((host->irq_flags & IRQF_SHARED) == 0) {
809                         /*
810                          * Probably not a shared PCI interrupt,
811                          * so we can safely try to do something about it:
812                          */
813                         unexpected_intr(irq, hwif);
814                 } else {
815                         /*
816                          * Whack the status register, just in case
817                          * we have a leftover pending IRQ.
818                          */
819                         (void)hwif->tp_ops->read_status(hwif);
820                 }
821                 goto out;
822         }
823
824         drive = hwif->cur_dev;
825
826         if (!drive_is_ready(drive))
827                 /*
828                  * This happens regularly when we share a PCI IRQ with
829                  * another device.  Unfortunately, it can also happen
830                  * with some buggy drives that trigger the IRQ before
831                  * their status register is up to date.  Hopefully we have
832                  * enough advance overhead that the latter isn't a problem.
833                  */
834                 goto out;
835
836         hwif->handler = NULL;
837         hwif->expiry = NULL;
838         hwif->req_gen++;
839         del_timer(&hwif->timer);
840         spin_unlock(&hwif->lock);
841
842         if (hwif->port_ops && hwif->port_ops->clear_irq)
843                 hwif->port_ops->clear_irq(drive);
844
845         if (drive->dev_flags & IDE_DFLAG_UNMASK)
846                 local_irq_enable_in_hardirq();
847
848         /* service this interrupt, may set handler for next interrupt */
849         startstop = handler(drive);
850
851         spin_lock_irq(&hwif->lock);
852         /*
853          * Note that handler() may have set things up for another
854          * interrupt to occur soon, but it cannot happen until
855          * we exit from this routine, because it will be the
856          * same irq as is currently being serviced here, and Linux
857          * won't allow another of the same (on any CPU) until we return.
858          */
859         if (startstop == ide_stopped && hwif->polling == 0) {
860                 BUG_ON(hwif->handler);
861                 rq_in_flight = hwif->rq;
862                 hwif->rq = NULL;
863                 ide_unlock_port(hwif);
864                 plug_device = 1;
865         }
866         irq_ret = IRQ_HANDLED;
867 out:
868         spin_unlock_irqrestore(&hwif->lock, flags);
869 out_early:
870         if (plug_device) {
871                 ide_unlock_host(hwif->host);
872                 ide_requeue_and_plug(drive, rq_in_flight);
873         }
874
875         return irq_ret;
876 }
877 EXPORT_SYMBOL_GPL(ide_intr);
878
879 void ide_pad_transfer(ide_drive_t *drive, int write, int len)
880 {
881         ide_hwif_t *hwif = drive->hwif;
882         u8 buf[4] = { 0 };
883
884         while (len > 0) {
885                 if (write)
886                         hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
887                 else
888                         hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
889                 len -= 4;
890         }
891 }
892 EXPORT_SYMBOL_GPL(ide_pad_transfer);