ide.c

基于组件方式开发操作系统的OSKIT源代码

	del_timer(&hwgroup->timer);	/* Is this needed?? */
	if (hwgroup->poll_timeout != 0) {	/* polling in progress? */
		spin_unlock_irqrestore(&hwgroup->spinlock, flags);
		handler(drive);
	} else if (drive_is_ready(drive)) {
		printk("%s: lost interrupt\n", drive->name);
		spin_unlock_irqrestore(&hwgroup->spinlock, flags);
		handler(drive);
	} else {
		if (drive->waiting_for_dma) {
			(void) hwgroup->hwif->dmaproc(ide_dma_end, drive);
			printk("%s: timeout waiting for DMA\n", drive->name);
	/*
	 *  need something here for HX PIIX3 UDMA and HPT343.......AMH
	 *  irq timeout: status=0x58 { DriveReady SeekComplete DataRequest }
	 */
		}
		spin_unlock_irqrestore(&hwgroup->spinlock, flags);
		ide_error(drive, "irq timeout", GET_STAT());
	}
	start_next_request(hwgroup, 0);
}

/*
 * 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
 * accidently invoked as a result of any valid command completion interrupt.
 *
 */
static void unexpected_intr (int irq, ide_hwgroup_t *hwgroup)
{
	byte stat;
	ide_hwif_t *hwif = hwgroup->hwif;

	/*
	 * handle the unexpected interrupt
	 */
	do {
		if (hwif->irq == irq) {
			stat = IN_BYTE(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 = 0, count = 0;
				++count;
				if (0 < (signed long)(jiffies - (last_msgtime + HZ))) {
					last_msgtime = jiffies;
					printk("%s%s: unexpected interrupt, status=0x%02x, count=%ld\n",
					 hwif->name, (hwif->next == hwgroup->hwif) ? "" : "(?)", stat, count);
				}
			}
		}
	} while ((hwif = hwif->next) != hwgroup->hwif);
}
/*
 * entry point for all interrupts, caller does __cli() for us
 */
void ide_intr (int irq, void *dev_id, struct pt_regs *regs)
{
	unsigned long flags;
	ide_hwgroup_t *hwgroup = (ide_hwgroup_t *)dev_id;
	ide_hwif_t *hwif;
	ide_drive_t *drive;
	ide_handler_t *handler;

	__cli();	/* local CPU only */
	spin_lock_irqsave(&hwgroup->spinlock, flags);
	hwif = hwgroup->hwif;
	if ((handler = hwgroup->handler) == NULL || hwgroup->poll_timeout != 0) {
		/*
		 * 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.
		 */
#ifdef CONFIG_BLK_DEV_IDEPCI
		if (IDE_PCI_DEVID_EQ(hwif->pci_devid, IDE_PCI_DEVID_NULL))
#endif	/* CONFIG_BLK_DEV_IDEPCI */
		{
			/*
			 * Probably not a shared PCI interrupt,
			 * so we can safely try to do something about it:
			 */
			(void)ide_ack_intr(hwif->io_ports[IDE_STATUS_OFFSET], hwif->io_ports[IDE_IRQ_OFFSET]);
			unexpected_intr(irq, hwgroup);
		}
		spin_unlock_irqrestore(&hwgroup->spinlock, flags);
		return;
	}
	drive = hwgroup->drive;
	if (!drive || !drive_is_ready(drive)) {
		spin_unlock_irqrestore(&hwgroup->spinlock, flags);
		return;
	}
	hwgroup->handler = NULL;
	(void)ide_ack_intr(hwif->io_ports[IDE_STATUS_OFFSET], hwif->io_ports[IDE_IRQ_OFFSET]);
	del_timer(&(hwgroup->timer));
	{
		struct request *rq;
		unsigned long block, sectors;

		if ((rq = hwgroup->rq) != NULL) {
			block = rq->sector;
			block += drive->part[MINOR(rq->rq_dev)&PARTN_MASK].start_sect + drive->sect0;
			sectors = drive->using_dma ? rq->nr_sectors : drive->mult_count ? drive->mult_count : 1;
		}
	}

	spin_unlock_irqrestore(&hwgroup->spinlock, flags);
	if (drive->unmask)
		ide__sti();	/* local CPU only */
	handler(drive);		/* service this interrupt, may set handler for next interrupt */
	/*
	 * 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 (on any CPU) until we return.
	 */
	start_next_request(hwgroup, hwif->irq);
}

/*
 * get_info_ptr() returns the (ide_drive_t *) for a given device number.
 * It returns NULL if the given device number does not match any present drives.
 */
static ide_drive_t *get_info_ptr (kdev_t i_rdev)
{
	int		major = MAJOR(i_rdev);
	unsigned int	h;

	for (h = 0; h < MAX_HWIFS; ++h) {
		ide_hwif_t  *hwif = &ide_hwifs[h];
		if (hwif->present && major == hwif->major) {
			unsigned unit = DEVICE_NR(i_rdev);
			if (unit < MAX_DRIVES) {
				ide_drive_t *drive = &hwif->drives[unit];
				if (drive->present)
					return drive;
			}
			break;
		}
	}
	return NULL;
}

/*
 * This function is intended to be used prior to invoking ide_do_drive_cmd().
 */
void ide_init_drive_cmd (struct request *rq)
{
	rq->buffer = NULL;
	rq->cmd = IDE_DRIVE_CMD;
	rq->sector = 0;
	rq->nr_sectors = 0;
	rq->current_nr_sectors = 0;
	rq->sem = NULL;
	rq->bh = NULL;
	rq->bhtail = NULL;
	rq->next = NULL;
}

/*
 * 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_next, then the rq is queued immediately after
 * the currently-being-processed-request (if any), and the function
 * returns without waiting for the new rq to be completed.  As above,
 * 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);
	unsigned int major = HWIF(drive)->major;
	struct request *cur_rq;
	struct semaphore sem = MUTEX_LOCKED;

	if (IS_PDC4030_DRIVE && rq->buffer != NULL)
		return -ENOSYS;  /* special drive cmds not supported */
	rq->errors = 0;
	rq->rq_status = RQ_ACTIVE;
	rq->rq_dev = MKDEV(major,(drive->select.b.unit)<<PARTN_BITS);
	if (action == ide_wait)
		rq->sem = &sem;

	spin_lock_irqsave(&io_request_lock, flags);
	cur_rq = drive->queue;
	if (cur_rq == NULL || action == ide_preempt) {
		rq->next = cur_rq;
		drive->queue = rq;
		if (action == ide_preempt)
			hwgroup->rq = NULL;
	} else {
		if (action == ide_wait || action == ide_end) {
			while (cur_rq->next != NULL)	/* find end of list */
				cur_rq = cur_rq->next;
		}
		rq->next = cur_rq->next;
		cur_rq->next = rq;
	}
	spin_unlock_irqrestore(&io_request_lock, flags);
	do_hwgroup_request(hwgroup);
	save_flags(flags);	/* all CPUs; overkill? */
	cli();			/* all CPUs; overkill? */
	if (action == ide_wait && rq->rq_status != RQ_INACTIVE)
		down(&sem);	/* wait for it to be serviced */
	restore_flags(flags);	/* all CPUs; overkill? */
	return rq->errors ? -EIO : 0;	/* return -EIO if errors */
}

/*
 * This routine is called to flush all partitions and partition tables
 * for a changed disk, and then re-read the new partition table.
 * If we are revalidating a disk because of a media change, then we
 * enter with usage == 0.  If we are using an ioctl, we automatically have
 * usage == 1 (we need an open channel to use an ioctl :-), so this
 * is our limit.
 */
int ide_revalidate_disk(kdev_t i_rdev)
{
	ide_drive_t *drive;
	ide_hwgroup_t *hwgroup;
	unsigned int p, major, minor;
	long flags;

	if ((drive = get_info_ptr(i_rdev)) == NULL)
		return -ENODEV;
	major = MAJOR(i_rdev);
	minor = drive->select.b.unit << PARTN_BITS;
	hwgroup = HWGROUP(drive);
	spin_lock_irqsave(&hwgroup->spinlock, flags);
	if (drive->busy || (drive->usage > 1)) {
		spin_unlock_irqrestore(&hwgroup->spinlock, flags);
		return -EBUSY;
	};
	drive->busy = 1;
	MOD_INC_USE_COUNT;
	spin_unlock_irqrestore(&hwgroup->spinlock, flags);

	for (p = 0; p < (1<<PARTN_BITS); ++p) {
		if (drive->part[p].nr_sects > 0) {
			kdev_t devp = MKDEV(major, minor+p);
			struct super_block * sb = get_super(devp);
			fsync_dev          (devp);
			if (sb)
				invalidate_inodes(sb);
			invalidate_buffers (devp);
			set_blocksize(devp, 1024);
		}
		drive->part[p].start_sect = 0;
		drive->part[p].nr_sects   = 0;
	};

	drive->part[0].nr_sects = current_capacity(drive);
	if ((drive->media != ide_disk && drive->media != ide_floppy) ||
	     drive->driver == NULL || !drive->part[0].nr_sects)
		drive->part[0].start_sect = -1;
	resetup_one_dev(HWIF(drive)->gd, drive->select.b.unit);

	drive->busy = 0;
	wake_up(&drive->wqueue);
	MOD_DEC_USE_COUNT;
	return 0;
}

static void revalidate_drives (void)
{
	ide_hwif_t *hwif;
	ide_drive_t *drive;
	int index, unit;

	for (index = 0; index < MAX_HWIFS; ++index) {
		hwif = &ide_hwifs[index];
		for (unit = 0; unit < MAX_DRIVES; ++unit) {
			drive = &ide_hwifs[index].drives[unit];
			if (drive->revalidate) {
				drive->revalidate = 0;
				if (!initializing)
					(void) ide_revalidate_disk(MKDEV(hwif->major, unit<<PARTN_BITS));
			}
		}
	}
}

static void ide_init_module (int type)
{
	int found = 0;
	ide_module_t *module = ide_modules;
	
	while (module) {
		if (module->type == type) {
			found = 1;
			(void) module->init();
		}
		module = module->next;
	}
	revalidate_drives();
#ifdef CONFIG_KMOD
	if (!found && type == IDE_PROBE_MODULE)
		(void) request_module("ide-probe");
#endif /* CONFIG_KMOD */
}

static int ide_open(struct inode * inode, struct file * filp)
{
	ide_drive_t *drive;
	int rc;

	if ((drive = get_info_ptr(inode->i_rdev)) == NULL)
		return -ENXIO;
	MOD_INC_USE_COUNT;
	if (drive->driver == NULL)
		ide_init_module(IDE_DRIVER_MODULE);
#ifdef CONFIG_KMOD
	if (drive->driver == NULL) {
		if (drive->media == ide_disk)
			(void) request_module("ide-disk");
		if (drive->media == ide_cdrom)
			(void) request_module("ide-cd");
		if (drive->media == ide_tape)
			(void) request_module("ide-tape");
		if (drive->media == ide_floppy)
			(void) request_module("ide-floppy");
	}
#endif /* CONFIG_KMOD */
	while (drive->busy)
		sleep_on(&drive->wqueue);
	drive->usage++;
	if (drive->driver != NULL) {
		if ((rc = DRIVER(drive)->open(inode, filp, drive)))
			MOD_DEC_USE_COUNT;
		return rc;
	}
	printk ("%s: driver not present\n", drive->name);
	drive->usage--;
	MOD_DEC_USE_COUNT;
	return -ENXIO;
}

/*
 * Releasing a block device means we sync() it, so that it can safely
 * be forgotten about...
 */
static int ide_release(struct inode * inode, struct file * file)
{
	ide_drive_t *drive;

	if ((drive = get_info_ptr(inode->i_rdev)) != NULL) {
		fsync_dev(inode->i_rdev);
		drive->usage--;
		if (drive->driver != NULL)
			DRIVER(drive)->release(inode, file, drive);
		MOD_DEC_USE_COUNT;
	}
	return 0;
}

int ide_replace_subdriver(ide_drive_t *drive, const char *driver)
{
	if (!drive->present || drive->busy || drive->usage)
		goto abort;
	if (drive->driver != NULL && DRIVER(drive)->cleanup(drive))
		goto abort;
	strncpy(drive->driver_req, driver, 9);
	ide_init_module(IDE_DRIVER_MODULE);
	drive->driver_req[0] = 0;
	ide_init_module(IDE_DRIVER_MODULE);
	if (DRIVER(drive) && !strcmp(DRIVER(drive)->name, driver))
		return 0;
abort:
	return 1;
}

void ide_unregister (unsigned int index)
{
#ifdef OSKIT
	printk(KERN_CRIT "ide_unregister called\n");
#else
	struct gendisk *gd, **gdp;
	ide_drive_t *drive, *d;
	ide_hwif_t *hwif, *g;
	ide_hwgroup_t *hwgroup;
	int irq_count = 0, unit, i;
	unsigned long flags;
	unsigned int p, minor;

	if (index >= MAX_HWIFS)
		return;
	save_flags(flags);	/* all CPUs */
	cli();			/* all CPUs */
	hwif = &ide_hwifs[index];
	if (!hwif->present)
		goto abort;