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/drivers/ide/ide-io.c

https://bitbucket.org/cresqo/cm7-p500-kernel
C | 900 lines | 539 code | 124 blank | 237 comment | 135 complexity | 6cad2e01bf0915ecd2e0cd0c97117340 MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  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
 57int 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}
 72EXPORT_SYMBOL_GPL(ide_end_rq);
 73
 74void 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
115int 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}
134EXPORT_SYMBOL(ide_complete_rq);
135
136void ide_kill_rq(ide_drive_t *drive, struct request *rq)
137{
138	u8 drv_req = blk_special_request(rq) && 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 (blk_fs_request(rq) == 0 && rq->errors == 0)
149			rq->errors = -EIO;
150	}
151
152	ide_complete_rq(drive, -EIO, blk_rq_bytes(rq));
153}
154
155static 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
165static 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
171static 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
185static 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
223void 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}
231EXPORT_SYMBOL_GPL(ide_map_sg);
232
233void 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}
239EXPORT_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
253static 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
280static 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 
306static ide_startstop_t start_request (ide_drive_t *drive, struct request *rq)
307{
308	ide_startstop_t startstop;
309
310	BUG_ON(!blk_rq_started(rq));
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 && blk_special_request(rq))
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);
372kill_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 
386void 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}
393EXPORT_SYMBOL(ide_stall_queue);
394
395static 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
405static inline void ide_unlock_port(ide_hwif_t *hwif)
406{
407	hwif->busy = 0;
408}
409
410static 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
424static 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/*
434 * Issue a new request to a device.
435 */
436void do_ide_request(struct request_queue *q)
437{
438	ide_drive_t	*drive = q->queuedata;
439	ide_hwif_t	*hwif = drive->hwif;
440	struct ide_host *host = hwif->host;
441	struct request	*rq = NULL;
442	ide_startstop_t	startstop;
443
444	/*
445	 * drive is doing pre-flush, ordered write, post-flush sequence. even
446	 * though that is 3 requests, it must be seen as a single transaction.
447	 * we must not preempt this drive until that is complete
448	 */
449	if (blk_queue_flushing(q))
450		/*
451		 * small race where queue could get replugged during
452		 * the 3-request flush cycle, just yank the plug since
453		 * we want it to finish asap
454		 */
455		blk_remove_plug(q);
456
457	spin_unlock_irq(q->queue_lock);
458
459	/* HLD do_request() callback might sleep, make sure it's okay */
460	might_sleep();
461
462	if (ide_lock_host(host, hwif))
463		goto plug_device_2;
464
465	spin_lock_irq(&hwif->lock);
466
467	if (!ide_lock_port(hwif)) {
468		ide_hwif_t *prev_port;
469
470		WARN_ON_ONCE(hwif->rq);
471repeat:
472		prev_port = hwif->host->cur_port;
473		if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
474		    time_after(drive->sleep, jiffies)) {
475			ide_unlock_port(hwif);
476			goto plug_device;
477		}
478
479		if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
480		    hwif != prev_port) {
481			ide_drive_t *cur_dev =
482				prev_port ? prev_port->cur_dev : NULL;
483
484			/*
485			 * set nIEN for previous port, drives in the
486			 * quirk list may not like intr setups/cleanups
487			 */
488			if (cur_dev &&
489			    (cur_dev->dev_flags & IDE_DFLAG_NIEN_QUIRK) == 0)
490				prev_port->tp_ops->write_devctl(prev_port,
491								ATA_NIEN |
492								ATA_DEVCTL_OBS);
493
494			hwif->host->cur_port = hwif;
495		}
496		hwif->cur_dev = drive;
497		drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
498
499		spin_unlock_irq(&hwif->lock);
500		spin_lock_irq(q->queue_lock);
501		/*
502		 * we know that the queue isn't empty, but this can happen
503		 * if the q->prep_rq_fn() decides to kill a request
504		 */
505		if (!rq)
506			rq = blk_fetch_request(drive->queue);
507
508		spin_unlock_irq(q->queue_lock);
509		spin_lock_irq(&hwif->lock);
510
511		if (!rq) {
512			ide_unlock_port(hwif);
513			goto out;
514		}
515
516		/*
517		 * Sanity: don't accept a request that isn't a PM request
518		 * if we are currently power managed. This is very important as
519		 * blk_stop_queue() doesn't prevent the blk_fetch_request()
520		 * above to return us whatever is in the queue. Since we call
521		 * ide_do_request() ourselves, we end up taking requests while
522		 * the queue is blocked...
523		 * 
524		 * We let requests forced at head of queue with ide-preempt
525		 * though. I hope that doesn't happen too much, hopefully not
526		 * unless the subdriver triggers such a thing in its own PM
527		 * state machine.
528		 */
529		if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
530		    blk_pm_request(rq) == 0 &&
531		    (rq->cmd_flags & REQ_PREEMPT) == 0) {
532			/* there should be no pending command at this point */
533			ide_unlock_port(hwif);
534			goto plug_device;
535		}
536
537		hwif->rq = rq;
538
539		spin_unlock_irq(&hwif->lock);
540		startstop = start_request(drive, rq);
541		spin_lock_irq(&hwif->lock);
542
543		if (startstop == ide_stopped) {
544			rq = hwif->rq;
545			hwif->rq = NULL;
546			goto repeat;
547		}
548	} else
549		goto plug_device;
550out:
551	spin_unlock_irq(&hwif->lock);
552	if (rq == NULL)
553		ide_unlock_host(host);
554	spin_lock_irq(q->queue_lock);
555	return;
556
557plug_device:
558	spin_unlock_irq(&hwif->lock);
559	ide_unlock_host(host);
560plug_device_2:
561	spin_lock_irq(q->queue_lock);
562
563	if (rq)
564		blk_requeue_request(q, rq);
565	if (!elv_queue_empty(q))
566		blk_plug_device(q);
567}
568
569void ide_requeue_and_plug(ide_drive_t *drive, struct request *rq)
570{
571	struct request_queue *q = drive->queue;
572	unsigned long flags;
573
574	spin_lock_irqsave(q->queue_lock, flags);
575
576	if (rq)
577		blk_requeue_request(q, rq);
578	if (!elv_queue_empty(q))
579		blk_plug_device(q);
580
581	spin_unlock_irqrestore(q->queue_lock, flags);
582}
583
584static int drive_is_ready(ide_drive_t *drive)
585{
586	ide_hwif_t *hwif = drive->hwif;
587	u8 stat = 0;
588
589	if (drive->waiting_for_dma)
590		return hwif->dma_ops->dma_test_irq(drive);
591
592	if (hwif->io_ports.ctl_addr &&
593	    (hwif->host_flags & IDE_HFLAG_BROKEN_ALTSTATUS) == 0)
594		stat = hwif->tp_ops->read_altstatus(hwif);
595	else
596		/* Note: this may clear a pending IRQ!! */
597		stat = hwif->tp_ops->read_status(hwif);
598
599	if (stat & ATA_BUSY)
600		/* drive busy: definitely not interrupting */
601		return 0;
602
603	/* drive ready: *might* be interrupting */
604	return 1;
605}
606
607/**
608 *	ide_timer_expiry	-	handle lack of an IDE interrupt
609 *	@data: timer callback magic (hwif)
610 *
611 *	An IDE command has timed out before the expected drive return
612 *	occurred. At this point we attempt to clean up the current
613 *	mess. If the current handler includes an expiry handler then
614 *	we invoke the expiry handler, and providing it is happy the
615 *	work is done. If that fails we apply generic recovery rules
616 *	invoking the handler and checking the drive DMA status. We
617 *	have an excessively incestuous relationship with the DMA
618 *	logic that wants cleaning up.
619 */
620 
621void ide_timer_expiry (unsigned long data)
622{
623	ide_hwif_t	*hwif = (ide_hwif_t *)data;
624	ide_drive_t	*uninitialized_var(drive);
625	ide_handler_t	*handler;
626	unsigned long	flags;
627	int		wait = -1;
628	int		plug_device = 0;
629	struct request	*uninitialized_var(rq_in_flight);
630
631	spin_lock_irqsave(&hwif->lock, flags);
632
633	handler = hwif->handler;
634
635	if (handler == NULL || hwif->req_gen != hwif->req_gen_timer) {
636		/*
637		 * Either a marginal timeout occurred
638		 * (got the interrupt just as timer expired),
639		 * or we were "sleeping" to give other devices a chance.
640		 * Either way, we don't really want to complain about anything.
641		 */
642	} else {
643		ide_expiry_t *expiry = hwif->expiry;
644		ide_startstop_t startstop = ide_stopped;
645
646		drive = hwif->cur_dev;
647
648		if (expiry) {
649			wait = expiry(drive);
650			if (wait > 0) { /* continue */
651				/* reset timer */
652				hwif->timer.expires = jiffies + wait;
653				hwif->req_gen_timer = hwif->req_gen;
654				add_timer(&hwif->timer);
655				spin_unlock_irqrestore(&hwif->lock, flags);
656				return;
657			}
658		}
659		hwif->handler = NULL;
660		hwif->expiry = NULL;
661		/*
662		 * We need to simulate a real interrupt when invoking
663		 * the handler() function, which means we need to
664		 * globally mask the specific IRQ:
665		 */
666		spin_unlock(&hwif->lock);
667		/* disable_irq_nosync ?? */
668		disable_irq(hwif->irq);
669		/* local CPU only, as if we were handling an interrupt */
670		local_irq_disable();
671		if (hwif->polling) {
672			startstop = handler(drive);
673		} else if (drive_is_ready(drive)) {
674			if (drive->waiting_for_dma)
675				hwif->dma_ops->dma_lost_irq(drive);
676			if (hwif->port_ops && hwif->port_ops->clear_irq)
677				hwif->port_ops->clear_irq(drive);
678
679			printk(KERN_WARNING "%s: lost interrupt\n",
680				drive->name);
681			startstop = handler(drive);
682		} else {
683			if (drive->waiting_for_dma)
684				startstop = ide_dma_timeout_retry(drive, wait);
685			else
686				startstop = ide_error(drive, "irq timeout",
687					hwif->tp_ops->read_status(hwif));
688		}
689		spin_lock_irq(&hwif->lock);
690		enable_irq(hwif->irq);
691		if (startstop == ide_stopped && hwif->polling == 0) {
692			rq_in_flight = hwif->rq;
693			hwif->rq = NULL;
694			ide_unlock_port(hwif);
695			plug_device = 1;
696		}
697	}
698	spin_unlock_irqrestore(&hwif->lock, flags);
699
700	if (plug_device) {
701		ide_unlock_host(hwif->host);
702		ide_requeue_and_plug(drive, rq_in_flight);
703	}
704}
705
706/**
707 *	unexpected_intr		-	handle an unexpected IDE interrupt
708 *	@irq: interrupt line
709 *	@hwif: port being processed
710 *
711 *	There's nothing really useful we can do with an unexpected interrupt,
712 *	other than reading the status register (to clear it), and logging it.
713 *	There should be no way that an irq can happen before we're ready for it,
714 *	so we needn't worry much about losing an "important" interrupt here.
715 *
716 *	On laptops (and "green" PCs), an unexpected interrupt occurs whenever
717 *	the drive enters "idle", "standby", or "sleep" mode, so if the status
718 *	looks "good", we just ignore the interrupt completely.
719 *
720 *	This routine assumes __cli() is in effect when called.
721 *
722 *	If an unexpected interrupt happens on irq15 while we are handling irq14
723 *	and if the two interfaces are "serialized" (CMD640), then it looks like
724 *	we could screw up by interfering with a new request being set up for 
725 *	irq15.
726 *
727 *	In reality, this is a non-issue.  The new command is not sent unless 
728 *	the drive is ready to accept one, in which case we know the drive is
729 *	not trying to interrupt us.  And ide_set_handler() is always invoked
730 *	before completing the issuance of any new drive command, so we will not
731 *	be accidentally invoked as a result of any valid command completion
732 *	interrupt.
733 */
734
735static void unexpected_intr(int irq, ide_hwif_t *hwif)
736{
737	u8 stat = hwif->tp_ops->read_status(hwif);
738
739	if (!OK_STAT(stat, ATA_DRDY, BAD_STAT)) {
740		/* Try to not flood the console with msgs */
741		static unsigned long last_msgtime, count;
742		++count;
743
744		if (time_after(jiffies, last_msgtime + HZ)) {
745			last_msgtime = jiffies;
746			printk(KERN_ERR "%s: unexpected interrupt, "
747				"status=0x%02x, count=%ld\n",
748				hwif->name, stat, count);
749		}
750	}
751}
752
753/**
754 *	ide_intr	-	default IDE interrupt handler
755 *	@irq: interrupt number
756 *	@dev_id: hwif
757 *	@regs: unused weirdness from the kernel irq layer
758 *
759 *	This is the default IRQ handler for the IDE layer. You should
760 *	not need to override it. If you do be aware it is subtle in
761 *	places
762 *
763 *	hwif is the interface in the group currently performing
764 *	a command. hwif->cur_dev is the drive and hwif->handler is
765 *	the IRQ handler to call. As we issue a command the handlers
766 *	step through multiple states, reassigning the handler to the
767 *	next step in the process. Unlike a smart SCSI controller IDE
768 *	expects the main processor to sequence the various transfer
769 *	stages. We also manage a poll timer to catch up with most
770 *	timeout situations. There are still a few where the handlers
771 *	don't ever decide to give up.
772 *
773 *	The handler eventually returns ide_stopped to indicate the
774 *	request completed. At this point we issue the next request
775 *	on the port and the process begins again.
776 */
777
778irqreturn_t ide_intr (int irq, void *dev_id)
779{
780	ide_hwif_t *hwif = (ide_hwif_t *)dev_id;
781	struct ide_host *host = hwif->host;
782	ide_drive_t *uninitialized_var(drive);
783	ide_handler_t *handler;
784	unsigned long flags;
785	ide_startstop_t startstop;
786	irqreturn_t irq_ret = IRQ_NONE;
787	int plug_device = 0;
788	struct request *uninitialized_var(rq_in_flight);
789
790	if (host->host_flags & IDE_HFLAG_SERIALIZE) {
791		if (hwif != host->cur_port)
792			goto out_early;
793	}
794
795	spin_lock_irqsave(&hwif->lock, flags);
796
797	if (hwif->port_ops && hwif->port_ops->test_irq &&
798	    hwif->port_ops->test_irq(hwif) == 0)
799		goto out;
800
801	handler = hwif->handler;
802
803	if (handler == NULL || hwif->polling) {
804		/*
805		 * Not expecting an interrupt from this drive.
806		 * That means this could be:
807		 *	(1) an interrupt from another PCI device
808		 *	sharing the same PCI INT# as us.
809		 * or	(2) a drive just entered sleep or standby mode,
810		 *	and is interrupting to let us know.
811		 * or	(3) a spurious interrupt of unknown origin.
812		 *
813		 * For PCI, we cannot tell the difference,
814		 * so in that case we just ignore it and hope it goes away.
815		 */
816		if ((host->irq_flags & IRQF_SHARED) == 0) {
817			/*
818			 * Probably not a shared PCI interrupt,
819			 * so we can safely try to do something about it:
820			 */
821			unexpected_intr(irq, hwif);
822		} else {
823			/*
824			 * Whack the status register, just in case
825			 * we have a leftover pending IRQ.
826			 */
827			(void)hwif->tp_ops->read_status(hwif);
828		}
829		goto out;
830	}
831
832	drive = hwif->cur_dev;
833
834	if (!drive_is_ready(drive))
835		/*
836		 * This happens regularly when we share a PCI IRQ with
837		 * another device.  Unfortunately, it can also happen
838		 * with some buggy drives that trigger the IRQ before
839		 * their status register is up to date.  Hopefully we have
840		 * enough advance overhead that the latter isn't a problem.
841		 */
842		goto out;
843
844	hwif->handler = NULL;
845	hwif->expiry = NULL;
846	hwif->req_gen++;
847	del_timer(&hwif->timer);
848	spin_unlock(&hwif->lock);
849
850	if (hwif->port_ops && hwif->port_ops->clear_irq)
851		hwif->port_ops->clear_irq(drive);
852
853	if (drive->dev_flags & IDE_DFLAG_UNMASK)
854		local_irq_enable_in_hardirq();
855
856	/* service this interrupt, may set handler for next interrupt */
857	startstop = handler(drive);
858
859	spin_lock_irq(&hwif->lock);
860	/*
861	 * Note that handler() may have set things up for another
862	 * interrupt to occur soon, but it cannot happen until
863	 * we exit from this routine, because it will be the
864	 * same irq as is currently being serviced here, and Linux
865	 * won't allow another of the same (on any CPU) until we return.
866	 */
867	if (startstop == ide_stopped && hwif->polling == 0) {
868		BUG_ON(hwif->handler);
869		rq_in_flight = hwif->rq;
870		hwif->rq = NULL;
871		ide_unlock_port(hwif);
872		plug_device = 1;
873	}
874	irq_ret = IRQ_HANDLED;
875out:
876	spin_unlock_irqrestore(&hwif->lock, flags);
877out_early:
878	if (plug_device) {
879		ide_unlock_host(hwif->host);
880		ide_requeue_and_plug(drive, rq_in_flight);
881	}
882
883	return irq_ret;
884}
885EXPORT_SYMBOL_GPL(ide_intr);
886
887void ide_pad_transfer(ide_drive_t *drive, int write, int len)
888{
889	ide_hwif_t *hwif = drive->hwif;
890	u8 buf[4] = { 0 };
891
892	while (len > 0) {
893		if (write)
894			hwif->tp_ops->output_data(drive, NULL, buf, min(4, len));
895		else
896			hwif->tp_ops->input_data(drive, NULL, buf, min(4, len));
897		len -= 4;
898	}
899}
900EXPORT_SYMBOL_GPL(ide_pad_transfer);