ide-io.c

linux 内核源代码

	/*
	 * end current dma transaction
	 */

	if (error < 0) {
		printk(KERN_WARNING "%s: DMA timeout error\n", drive->name);
		(void)HWIF(drive)->ide_dma_end(drive);
		ret = ide_error(drive, "dma timeout error",
						hwif->INB(IDE_STATUS_REG));
	} else {
		printk(KERN_WARNING "%s: DMA timeout retry\n", drive->name);
		hwif->dma_timeout(drive);
	}

	/*
	 * disable dma for now, but remember that we did so because of
	 * a timeout -- we'll reenable after we finish this next request
	 * (or rather the first chunk of it) in pio.
	 */
	drive->retry_pio++;
	drive->state = DMA_PIO_RETRY;
	hwif->dma_off_quietly(drive);

	/*
	 * un-busy drive etc (hwgroup->busy is cleared on return) and
	 * make sure request is sane
	 */
	rq = HWGROUP(drive)->rq;

	if (!rq)
		goto out;

	HWGROUP(drive)->rq = NULL;

	rq->errors = 0;

	if (!rq->bio)
		goto out;

	rq->sector = rq->bio->bi_sector;
	rq->current_nr_sectors = bio_iovec(rq->bio)->bv_len >> 9;
	rq->hard_cur_sectors = rq->current_nr_sectors;
	rq->buffer = bio_data(rq->bio);
out:
	return ret;
}

/**
 *	ide_timer_expiry	-	handle lack of an IDE interrupt
 *	@data: timer callback magic (hwgroup)
 *
 *	An IDE command has timed out before the expected drive return
 *	occurred. At this point we attempt to clean up the current
 *	mess. If the current handler includes an expiry handler then
 *	we invoke the expiry handler, and providing it is happy the
 *	work is done. If that fails we apply generic recovery rules
 *	invoking the handler and checking the drive DMA status. We
 *	have an excessively incestuous relationship with the DMA
 *	logic that wants cleaning up.
 */
 
void ide_timer_expiry (unsigned long data)
{
	ide_hwgroup_t	*hwgroup = (ide_hwgroup_t *) data;
	ide_handler_t	*handler;
	ide_expiry_t	*expiry;
	unsigned long	flags;
	unsigned long	wait = -1;

	spin_lock_irqsave(&ide_lock, flags);

	if (((handler = hwgroup->handler) == NULL) ||
	    (hwgroup->req_gen != hwgroup->req_gen_timer)) {
		/*
		 * Either a marginal timeout occurred
		 * (got the interrupt just as timer expired),
		 * or we were "sleeping" to give other devices a chance.
		 * Either way, we don't really want to complain about anything.
		 */
		if (hwgroup->sleeping) {
			hwgroup->sleeping = 0;
			hwgroup->busy = 0;
		}
	} else {
		ide_drive_t *drive = hwgroup->drive;
		if (!drive) {
			printk(KERN_ERR "ide_timer_expiry: hwgroup->drive was NULL\n");
			hwgroup->handler = NULL;
		} else {
			ide_hwif_t *hwif;
			ide_startstop_t startstop = ide_stopped;
			if (!hwgroup->busy) {
				hwgroup->busy = 1;	/* paranoia */
				printk(KERN_ERR "%s: ide_timer_expiry: hwgroup->busy was 0 ??\n", drive->name);
			}
			if ((expiry = hwgroup->expiry) != NULL) {
				/* continue */
				if ((wait = expiry(drive)) > 0) {
					/* reset timer */
					hwgroup->timer.expires  = jiffies + wait;
					hwgroup->req_gen_timer = hwgroup->req_gen;
					add_timer(&hwgroup->timer);
					spin_unlock_irqrestore(&ide_lock, flags);
					return;
				}
			}
			hwgroup->handler = NULL;
			/*
			 * We need to simulate a real interrupt when invoking
			 * the handler() function, which means we need to
			 * globally mask the specific IRQ:
			 */
			spin_unlock(&ide_lock);
			hwif  = HWIF(drive);
#if DISABLE_IRQ_NOSYNC
			disable_irq_nosync(hwif->irq);
#else
			/* disable_irq_nosync ?? */
			disable_irq(hwif->irq);
#endif /* DISABLE_IRQ_NOSYNC */
			/* local CPU only,
			 * as if we were handling an interrupt */
			local_irq_disable();
			if (hwgroup->polling) {
				startstop = handler(drive);
			} else if (drive_is_ready(drive)) {
				if (drive->waiting_for_dma)
					hwgroup->hwif->dma_lost_irq(drive);
				(void)ide_ack_intr(hwif);
				printk(KERN_WARNING "%s: lost interrupt\n", drive->name);
				startstop = handler(drive);
			} else {
				if (drive->waiting_for_dma) {
					startstop = ide_dma_timeout_retry(drive, wait);
				} else
					startstop =
					ide_error(drive, "irq timeout", hwif->INB(IDE_STATUS_REG));
			}
			drive->service_time = jiffies - drive->service_start;
			spin_lock_irq(&ide_lock);
			enable_irq(hwif->irq);
			if (startstop == ide_stopped)
				hwgroup->busy = 0;
		}
	}
	ide_do_request(hwgroup, IDE_NO_IRQ);
	spin_unlock_irqrestore(&ide_lock, flags);
}

/**
 *	unexpected_intr		-	handle an unexpected IDE interrupt
 *	@irq: interrupt line
 *	@hwgroup: hwgroup being processed
 *
 *	There's nothing really useful we can do with an unexpected interrupt,
 *	other than reading the status register (to clear it), and logging it.
 *	There should be no way that an irq can happen before we're ready for it,
 *	so we needn't worry much about losing an "important" interrupt here.
 *
 *	On laptops (and "green" PCs), an unexpected interrupt occurs whenever
 *	the drive enters "idle", "standby", or "sleep" mode, so if the status
 *	looks "good", we just ignore the interrupt completely.
 *
 *	This routine assumes __cli() is in effect when called.
 *
 *	If an unexpected interrupt happens on irq15 while we are handling irq14
 *	and if the two interfaces are "serialized" (CMD640), then it looks like
 *	we could screw up by interfering with a new request being set up for 
 *	irq15.
 *
 *	In reality, this is a non-issue.  The new command is not sent unless 
 *	the drive is ready to accept one, in which case we know the drive is
 *	not trying to interrupt us.  And ide_set_handler() is always invoked
 *	before completing the issuance of any new drive command, so we will not
 *	be accidentally invoked as a result of any valid command completion
 *	interrupt.
 *
 *	Note that we must walk the entire hwgroup here. We know which hwif
 *	is doing the current command, but we don't know which hwif burped
 *	mysteriously.
 */
 
static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
{
	u8 stat;
	ide_hwif_t *hwif = hwgroup->hwif;

	/*
	 * handle the unexpected interrupt
	 */
	do {
		if (hwif->irq == irq) {
			stat = hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
			if (!OK_STAT(stat, READY_STAT, BAD_STAT)) {
				/* Try to not flood the console with msgs */
				static unsigned long last_msgtime, count;
				++count;
				if (time_after(jiffies, last_msgtime + HZ)) {
					last_msgtime = jiffies;
					printk(KERN_ERR "%s%s: unexpected interrupt, "
						"status=0x%02x, count=%ld\n",
						hwif->name,
						(hwif->next==hwgroup->hwif) ? "" : "(?)", stat, count);
				}
			}
		}
	} while ((hwif = hwif->next) != hwgroup->hwif);
}

/**
 *	ide_intr	-	default IDE interrupt handler
 *	@irq: interrupt number
 *	@dev_id: hwif group
 *	@regs: unused weirdness from the kernel irq layer
 *
 *	This is the default IRQ handler for the IDE layer. You should
 *	not need to override it. If you do be aware it is subtle in
 *	places
 *
 *	hwgroup->hwif is the interface in the group currently performing
 *	a command. hwgroup->drive is the drive and hwgroup->handler is
 *	the IRQ handler to call. As we issue a command the handlers
 *	step through multiple states, reassigning the handler to the
 *	next step in the process. Unlike a smart SCSI controller IDE
 *	expects the main processor to sequence the various transfer
 *	stages. We also manage a poll timer to catch up with most
 *	timeout situations. There are still a few where the handlers
 *	don't ever decide to give up.
 *
 *	The handler eventually returns ide_stopped to indicate the
 *	request completed. At this point we issue the next request
 *	on the hwgroup and the process begins again.
 */
 
irqreturn_t ide_intr (int irq, void *dev_id)
{
	unsigned long flags;
	ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
	ide_hwif_t *hwif;
	ide_drive_t *drive;
	ide_handler_t *handler;
	ide_startstop_t startstop;

	spin_lock_irqsave(&ide_lock, flags);
	hwif = hwgroup->hwif;

	if (!ide_ack_intr(hwif)) {
		spin_unlock_irqrestore(&ide_lock, flags);
		return IRQ_NONE;
	}

	if ((handler = hwgroup->handler) == NULL || hwgroup->polling) {
		/*
		 * Not expecting an interrupt from this drive.
		 * That means this could be:
		 *	(1) an interrupt from another PCI device
		 *	sharing the same PCI INT# as us.
		 * or	(2) a drive just entered sleep or standby mode,
		 *	and is interrupting to let us know.
		 * or	(3) a spurious interrupt of unknown origin.
		 *
		 * For PCI, we cannot tell the difference,
		 * so in that case we just ignore it and hope it goes away.
		 *
		 * FIXME: unexpected_intr should be hwif-> then we can
		 * remove all the ifdef PCI crap
		 */
#ifdef CONFIG_BLK_DEV_IDEPCI
		if (hwif->pci_dev && !hwif->pci_dev->vendor)
#endif	/* CONFIG_BLK_DEV_IDEPCI */
		{
			/*
			 * Probably not a shared PCI interrupt,
			 * so we can safely try to do something about it:
			 */
			unexpected_intr(irq, hwgroup);
#ifdef CONFIG_BLK_DEV_IDEPCI
		} else {
			/*
			 * Whack the status register, just in case
			 * we have a leftover pending IRQ.
			 */
			(void) hwif->INB(hwif->io_ports[IDE_STATUS_OFFSET]);
#endif /* CONFIG_BLK_DEV_IDEPCI */
		}
		spin_unlock_irqrestore(&ide_lock, flags);
		return IRQ_NONE;
	}
	drive = hwgroup->drive;
	if (!drive) {
		/*
		 * This should NEVER happen, and there isn't much
		 * we could do about it here.
		 *
		 * [Note - this can occur if the drive is hot unplugged]
		 */
		spin_unlock_irqrestore(&ide_lock, flags);
		return IRQ_HANDLED;
	}
	if (!drive_is_ready(drive)) {
		/*
		 * This happens regularly when we share a PCI IRQ with
		 * another device.  Unfortunately, it can also happen
		 * with some buggy drives that trigger the IRQ before
		 * their status register is up to date.  Hopefully we have
		 * enough advance overhead that the latter isn't a problem.
		 */
		spin_unlock_irqrestore(&ide_lock, flags);
		return IRQ_NONE;
	}
	if (!hwgroup->busy) {
		hwgroup->busy = 1;	/* paranoia */
		printk(KERN_ERR "%s: ide_intr: hwgroup->busy was 0 ??\n", drive->name);
	}
	hwgroup->handler = NULL;
	hwgroup->req_gen++;
	del_timer(&hwgroup->timer);
	spin_unlock(&ide_lock);

	/* Some controllers might set DMA INTR no matter DMA or PIO;
	 * bmdma status might need to be cleared even for
	 * PIO interrupts to prevent spurious/lost irq.
	 */
	if (hwif->ide_dma_clear_irq && !(drive->waiting_for_dma))
		/* ide_dma_end() needs bmdma status for error checking.
		 * So, skip clearing bmdma status here and leave it
		 * to ide_dma_end() if this is dma interrupt.
		 */
		hwif->ide_dma_clear_irq(drive);

	if (drive->unmask)
		local_irq_enable_in_hardirq();
	/* service this interrupt, may set handler for next interrupt */
	startstop = handler(drive);
	spin_lock_irq(&ide_lock);

	/*
	 * Note that handler() may have set things up for another
	 * interrupt to occur soon, but it cannot happen until
	 * we exit from this routine, because it will be the
	 * same irq as is currently being serviced here, and Linux
	 * won't allow another of the same (on any CPU) until we return.
	 */
	drive->service_time = jiffies - drive->service_start;
	if (startstop == ide_stopped) {
		if (hwgroup->handler == NULL) {	/* paranoia */
			hwgroup->busy = 0;
			ide_do_request(hwgroup, hwif->irq);
		} else {
			printk(KERN_ERR "%s: ide_intr: huh? expected NULL handler "
				"on exit\n", drive->name);
		}
	}
	spin_unlock_irqrestore(&ide_lock, flags);
	return IRQ_HANDLED;
}

/**
 *	ide_init_drive_cmd	-	initialize a drive command request
 *	@rq: request object
 *
 *	Initialize a request before we fill it in and send it down to
 *	ide_do_drive_cmd. Commands must be set up by this function. Right
 *	now it doesn't do a lot, but if that changes abusers will have a
 *	nasty surprise.
 */

void ide_init_drive_cmd (struct request *rq)
{
	memset(rq, 0, sizeof(*rq));
	rq->cmd_type = REQ_TYPE_ATA_CMD;
	rq->ref_count = 1;
}

EXPORT_SYMBOL(ide_init_drive_cmd);

/**
 *	ide_do_drive_cmd	-	issue IDE special command
 *	@drive: device to issue command
 *	@rq: request to issue
 *	@action: action for processing
 *
 *	This function issues a special IDE device request
 *	onto the request queue.
 *
 *	If action is ide_wait, then the rq is queued at the end of the
 *	request queue, and the function sleeps until it has been processed.
 *	This is for use when invoked from an ioctl handler.
 *
 *	If action is ide_preempt, then the rq is queued at the head of
 *	the request queue, displacing the currently-being-processed
 *	request and this function returns immediately without waiting
 *	for the new rq to be completed.  This is VERY DANGEROUS, and is
 *	intended for careful use by the ATAPI tape/cdrom driver code.
 *
 *	If action is ide_end, then the rq is queued at the end of the
 *	request queue, and the function returns immediately without waiting
 *	for the new rq to be completed. This is again intended for careful
 *	use by the ATAPI tape/cdrom driver code.
 */
 
int ide_do_drive_cmd (ide_drive_t *drive, struct request *rq, ide_action_t action)
{
	unsigned long flags;
	ide_hwgroup_t *hwgroup = HWGROUP(drive);
	DECLARE_COMPLETION_ONSTACK(wait);
	int where = ELEVATOR_INSERT_BACK, err;
	int must_wait = (action == ide_wait || action == ide_head_wait);

	rq->errors = 0;

	/*
	 * we need to hold an extra reference to request for safe inspection
	 * after completion
	 */
	if (must_wait) {
		rq->ref_count++;
		rq->end_io_data = &wait;
		rq->end_io = blk_end_sync_rq;
	}

	spin_lock_irqsave(&ide_lock, flags);
	if (action == ide_preempt)
		hwgroup->rq = NULL;
	if (action == ide_preempt || action == ide_head_wait) {
		where = ELEVATOR_INSERT_FRONT;
		rq->cmd_flags |= REQ_PREEMPT;
	}
	__elv_add_request(drive->queue, rq, where, 0);
	ide_do_request(hwgroup, IDE_NO_IRQ);
	spin_unlock_irqrestore(&ide_lock, flags);

	err = 0;
	if (must_wait) {
		wait_for_completion(&wait);
		if (rq->errors)
			err = -EIO;

		blk_put_request(rq);
	}

	return err;
}

EXPORT_SYMBOL(ide_do_drive_cmd);