ide.c

基于组件方式开发操作系统的OSKIT源代码

	udelay(1);	/* need to guarantee 400ns since last command was issued */
#endif
	if (GET_STAT() & BUSY_STAT)
		return 0;	/* drive busy:  definitely not interrupting */
	return 1;		/* drive ready: *might* be interrupting */
}

/*
 * This is our end_request replacement function.
 */
void ide_end_request(byte uptodate, ide_hwgroup_t *hwgroup)
{
	struct request *rq;
	unsigned long flags;

	spin_lock_irqsave(&io_request_lock, flags);
	rq = hwgroup->rq;

	if (!end_that_request_first(rq, uptodate, hwgroup->drive->name)) {
		add_blkdev_randomness(MAJOR(rq->rq_dev));
		hwgroup->drive->queue = rq->next;
        	blk_dev[MAJOR(rq->rq_dev)].current_request = NULL;
        	hwgroup->rq = NULL;
		end_that_request_last(rq);
	}
	spin_unlock_irqrestore(&io_request_lock, flags);
}

/*
 * This should get invoked any time we exit the driver to
 * wait for an interrupt response from a drive.  handler() points
 * at the appropriate code to handle the next interrupt, and a
 * timer is started to prevent us from waiting forever in case
 * something goes wrong (see the ide_timer_expiry() handler later on).
 */
void ide_set_handler (ide_drive_t *drive, ide_handler_t *handler, unsigned int timeout)
{
	unsigned long flags;
	ide_hwgroup_t *hwgroup = HWGROUP(drive);

	spin_lock_irqsave(&hwgroup->spinlock, flags);
#ifdef DEBUG
	if (hwgroup->handler != NULL) {
		printk("%s: ide_set_handler: handler not null; old=%p, new=%p\n",
			drive->name, hwgroup->handler, handler);
	}
#endif
	hwgroup->handler       = handler;
	hwgroup->timer.expires = jiffies + timeout;
	add_timer(&(hwgroup->timer));
	spin_unlock_irqrestore(&hwgroup->spinlock, flags);
}

/*
 * current_capacity() returns the capacity (in sectors) of a drive
 * according to its current geometry/LBA settings.
 */
static unsigned long current_capacity (ide_drive_t *drive)
{
	if (!drive->present)
		return 0;
	if (drive->driver != NULL)
		return DRIVER(drive)->capacity(drive);
	return 0;
}

/*
 * ide_geninit() is called exactly *once* for each major, from genhd.c,
 * at the beginning of the initial partition check for the drives.
 */
void ide_geninit (struct gendisk *gd)
{
	unsigned int unit;
	ide_hwif_t *hwif = gd->real_devices;

	for (unit = 0; unit < gd->nr_real; ++unit) {
		ide_drive_t *drive = &hwif->drives[unit];

		drive->part[0].nr_sects = current_capacity(drive);
		if (!drive->present || (drive->media != ide_disk && drive->media != ide_floppy) ||
		    drive->driver == NULL || !drive->part[0].nr_sects)
			drive->part[0].start_sect = -1; /* skip partition check */
	}
}

static void do_reset1 (ide_drive_t *, int);		/* needed below */

/*
 * atapi_reset_pollfunc() gets invoked to poll the interface for completion every 50ms
 * during an atapi drive reset operation. If the drive has not yet responded,
 * and we have not yet hit our maximum waiting time, then the timer is restarted
 * for another 50ms.
 */
static void atapi_reset_pollfunc (ide_drive_t *drive)
{
	ide_hwgroup_t *hwgroup = HWGROUP(drive);
	byte stat;

	SELECT_DRIVE(HWIF(drive),drive);
	udelay (10);

	if (OK_STAT(stat=GET_STAT(), 0, BUSY_STAT)) {
		printk("%s: ATAPI reset complete\n", drive->name);
	} else {
		if (0 < (signed long)(hwgroup->poll_timeout - jiffies)) {
			ide_set_handler (drive, &atapi_reset_pollfunc, HZ/20);
			return;	/* continue polling */
		}
		hwgroup->poll_timeout = 0;	/* end of polling */
		printk("%s: ATAPI reset timed-out, status=0x%02x\n", drive->name, stat);
		do_reset1 (drive, 1);	/* do it the old fashioned way */
		return;
	}
	hwgroup->poll_timeout = 0;	/* done polling */
}

/*
 * reset_pollfunc() gets invoked to poll the interface for completion every 50ms
 * during an ide reset operation. If the drives have not yet responded,
 * and we have not yet hit our maximum waiting time, then the timer is restarted
 * for another 50ms.
 */
static void reset_pollfunc (ide_drive_t *drive)
{
	ide_hwgroup_t *hwgroup = HWGROUP(drive);
	ide_hwif_t *hwif = HWIF(drive);
	byte tmp;

	if (!OK_STAT(tmp=GET_STAT(), 0, BUSY_STAT)) {
		if (0 < (signed long)(hwgroup->poll_timeout - jiffies)) {
			ide_set_handler (drive, &reset_pollfunc, HZ/20);
			return;	/* continue polling */
		}
		printk("%s: reset timed-out, status=0x%02x\n", hwif->name, tmp);
	} else  {
		printk("%s: reset: ", hwif->name);
		if ((tmp = GET_ERR()) == 1)
			printk("success\n");
		else {
#if FANCY_STATUS_DUMPS
			printk("master: ");
			switch (tmp & 0x7f) {
				case 1: printk("passed");
					break;
				case 2: printk("formatter device error");
					break;
				case 3: printk("sector buffer error");
					break;
				case 4: printk("ECC circuitry error");
					break;
				case 5: printk("controlling MPU error");
					break;
				default:printk("error (0x%02x?)", tmp);
			}
			if (tmp & 0x80)
				printk("; slave: failed");
			printk("\n");
#else
			printk("failed\n");
#endif /* FANCY_STATUS_DUMPS */
		}
	}
	hwgroup->poll_timeout = 0;	/* done polling */
}

static void pre_reset (ide_drive_t *drive)
{
	if (!drive->keep_settings) {
		drive->unmask = 0;
		drive->io_32bit = 0;
		if (drive->using_dma)
			(void) HWIF(drive)->dmaproc(ide_dma_off, drive);
	}
	if (drive->driver != NULL)
		DRIVER(drive)->pre_reset(drive);
}

/*
 * do_reset1() attempts to recover a confused drive by resetting it.
 * Unfortunately, resetting a disk drive actually resets all devices on
 * the same interface, so it can really be thought of as resetting the
 * interface rather than resetting the drive.
 *
 * ATAPI devices have their own reset mechanism which allows them to be
 * individually reset without clobbering other devices on the same interface.
 *
 * Unfortunately, the IDE interface does not generate an interrupt to let
 * us know when the reset operation has finished, so we must poll for this.
 * Equally poor, though, is the fact that this may a very long time to complete,
 * (up to 30 seconds worstcase).  So, instead of busy-waiting here for it,
 * we set a timer to poll at 50ms intervals.
 */
static void do_reset1 (ide_drive_t *drive, int  do_not_try_atapi)
{
	unsigned int unit;
	unsigned long flags;
	ide_hwif_t *hwif = HWIF(drive);
	ide_hwgroup_t *hwgroup = HWGROUP(drive);

	__save_flags(flags);	/* local CPU only */
	__cli();		/* local CPU only */

	/* For an ATAPI device, first try an ATAPI SRST. */
	if (drive->media != ide_disk && !do_not_try_atapi) {
		pre_reset(drive);
		SELECT_DRIVE(hwif,drive);
		udelay (20);
		OUT_BYTE (WIN_SRST, IDE_COMMAND_REG);
		hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
		ide_set_handler (drive, &atapi_reset_pollfunc, HZ/20);
		__restore_flags (flags);	/* local CPU only */
		return;
	}

	/*
	 * First, reset any device state data we were maintaining
	 * for any of the drives on this interface.
	 */
	for (unit = 0; unit < MAX_DRIVES; ++unit)
		pre_reset(&hwif->drives[unit]);

#if OK_TO_RESET_CONTROLLER
	/*
	 * Note that we also set nIEN while resetting the device,
	 * to mask unwanted interrupts from the interface during the reset.
	 * However, due to the design of PC hardware, this will cause an
	 * immediate interrupt due to the edge transition it produces.
	 * This single interrupt gives us a "fast poll" for drives that
	 * recover from reset very quickly, saving us the first 50ms wait time.
	 */
	OUT_BYTE(drive->ctl|6,IDE_CONTROL_REG);	/* set SRST and nIEN */
	udelay(10);			/* more than enough time */
	OUT_BYTE(drive->ctl|2,IDE_CONTROL_REG);	/* clear SRST, leave nIEN */
	udelay(10);			/* more than enough time */
	hwgroup->poll_timeout = jiffies + WAIT_WORSTCASE;
	ide_set_handler (drive, &reset_pollfunc, HZ/20);
#endif	/* OK_TO_RESET_CONTROLLER */

	__restore_flags (flags);	/* local CPU only */
}

/*
 * ide_do_reset() is the entry point to the drive/interface reset code.
 */
void ide_do_reset (ide_drive_t *drive)
{
	do_reset1 (drive, 0);
}

/*
 * Clean up after success/failure of an explicit drive cmd
 */
void ide_end_drive_cmd (ide_drive_t *drive, byte stat, byte err)
{
	unsigned long flags;
	struct request *rq = HWGROUP(drive)->rq;

	if (rq->cmd == IDE_DRIVE_CMD) {
		byte *args = (byte *) rq->buffer;
		rq->errors = !OK_STAT(stat,READY_STAT,BAD_STAT);
		if (args) {
			args[0] = stat;
			args[1] = err;
			args[2] = IN_BYTE(IDE_NSECTOR_REG);
		}
	}
	spin_lock_irqsave(&io_request_lock, flags);
	drive->queue = rq->next;
	blk_dev[MAJOR(rq->rq_dev)].current_request = NULL;
	HWGROUP(drive)->rq = NULL;
	rq->rq_status = RQ_INACTIVE;
	spin_unlock_irqrestore(&io_request_lock, flags);
	save_flags(flags);	/* all CPUs; overkill? */
	cli();			/* all CPUs; overkill? */
	if (rq->sem != NULL)
		up(rq->sem);	/* inform originator that rq has been serviced */
	restore_flags(flags);	/* all CPUs; overkill? */
}

/*
 * Error reporting, in human readable form (luxurious, but a memory hog).
 */
byte ide_dump_status (ide_drive_t *drive, const char *msg, byte stat)
{
	unsigned long flags;
	byte err = 0;

	__save_flags (flags);	/* local CPU only */
	ide__sti();		/* local CPU only */
	printk("%s: %s: status=0x%02x", drive->name, msg, stat);
#if FANCY_STATUS_DUMPS
	printk(" { ");
	if (stat & BUSY_STAT)
		printk("Busy ");
	else {
		if (stat & READY_STAT)	printk("DriveReady ");
		if (stat & WRERR_STAT)	printk("DeviceFault ");
		if (stat & SEEK_STAT)	printk("SeekComplete ");
		if (stat & DRQ_STAT)	printk("DataRequest ");
		if (stat & ECC_STAT)	printk("CorrectedError ");
		if (stat & INDEX_STAT)	printk("Index ");
		if (stat & ERR_STAT)	printk("Error ");
	}
	printk("}");
#endif	/* FANCY_STATUS_DUMPS */
	printk("\n");
	if ((stat & (BUSY_STAT|ERR_STAT)) == ERR_STAT) {
		err = GET_ERR();
		printk("%s: %s: error=0x%02x", drive->name, msg, err);
#if FANCY_STATUS_DUMPS
		if (drive->media == ide_disk) {
			printk(" { ");
			if (err & ABRT_ERR)	printk("DriveStatusError ");
			if (err & ICRC_ERR)	printk((err & ABRT_ERR) ? "BadCRC " : "BadSector ");
			if (err & ECC_ERR)	printk("UncorrectableError ");
			if (err & ID_ERR)	printk("SectorIdNotFound ");
			if (err & TRK0_ERR)	printk("TrackZeroNotFound ");
			if (err & MARK_ERR)	printk("AddrMarkNotFound ");
			printk("}");
			if ((err & (BBD_ERR | ABRT_ERR)) == BBD_ERR || (err & (ECC_ERR|ID_ERR|MARK_ERR))) {
				byte cur = IN_BYTE(IDE_SELECT_REG);
				if (cur & 0x40) {	/* using LBA? */
					printk(", LBAsect=%ld", (unsigned long)
					 ((cur&0xf)<<24)
					 |(IN_BYTE(IDE_HCYL_REG)<<16)
					 |(IN_BYTE(IDE_LCYL_REG)<<8)
					 | IN_BYTE(IDE_SECTOR_REG));
				} else {
					printk(", CHS=%d/%d/%d",
					 (IN_BYTE(IDE_HCYL_REG)<<8) +
					  IN_BYTE(IDE_LCYL_REG),
					  cur & 0xf,
					  IN_BYTE(IDE_SECTOR_REG));
				}
				if (HWGROUP(drive)->rq)
					printk(", sector=%ld", HWGROUP(drive)->rq->sector);
			}
		}
#endif	/* FANCY_STATUS_DUMPS */
		printk("\n");
	}
	__restore_flags (flags);	/* local CPU only */
	return err;
}

/*
 * try_to_flush_leftover_data() is invoked in response to a drive
 * unexpectedly having its DRQ_STAT bit set.  As an alternative to
 * resetting the drive, this routine tries to clear the condition
 * by read a sector's worth of data from the drive.  Of course,
 * this may not help if the drive is *waiting* for data from *us*.
 */
static void try_to_flush_leftover_data (ide_drive_t *drive)
{
	int i = (drive->mult_count ? drive->mult_count : 1) * SECTOR_WORDS;

	if (drive->media != ide_disk)
		return;
	while (i > 0) {
		unsigned long buffer[16];
		unsigned int wcount = (i > 16) ? 16 : i;
		i -= wcount;
		ide_input_data (drive, buffer, wcount);
	}
}

/*
 * ide_error() takes action based on the error returned by the drive.
 */
void ide_error (ide_drive_t *drive, const char *msg, byte stat)
{
	struct request *rq;
	byte err;

	err = ide_dump_status(drive, msg, stat);
	if (drive == NULL || (rq = HWGROUP(drive)->rq) == NULL)
		return;
	/* retry only "normal" I/O: */
	if (rq->cmd == IDE_DRIVE_CMD) {
		rq->errors = 1;
		ide_end_drive_cmd(drive, stat, err);
		return;
	}
	if (stat & BUSY_STAT || ((stat & WRERR_STAT) && !drive->nowerr)) { /* other bits are useless when BUSY */
		rq->errors |= ERROR_RESET;
	} else {
		if (drive->media == ide_disk && (stat & ERR_STAT)) {
			/* err has different meaning on cdrom and tape */
			if (err == ABRT_ERR) {
				if (drive->select.b.lba && IN_BYTE(IDE_COMMAND_REG) == WIN_SPECIFY)
					return;	/* some newer drives don't support WIN_SPECIFY */
			} else if ((err & (ABRT_ERR | ICRC_ERR)) == (ABRT_ERR | ICRC_ERR))
				; /* UDMA crc error -- just retry the operation */
			else if (err & (BBD_ERR | ECC_ERR))	/* retries won't help these */
				rq->errors = ERROR_MAX;
			else if (err & TRK0_ERR)	/* help it find track zero */
				rq->errors |= ERROR_RECAL;
		}
		if ((stat & DRQ_STAT) && rq->cmd != WRITE)
			try_to_flush_leftover_data(drive);
	}
	if (GET_STAT() & (BUSY_STAT|DRQ_STAT))
		rq->errors |= ERROR_RESET;	/* Mmmm.. timing problem */

	if (rq->errors >= ERROR_MAX) {
		if (drive->driver != NULL)
			DRIVER(drive)->end_request(0, HWGROUP(drive));
		else
	 		ide_end_request(0, HWGROUP(drive));
	} else {
		if ((rq->errors & ERROR_RESET) == ERROR_RESET) {
			++rq->errors;
			ide_do_reset(drive);
			return;
		} else if ((rq->errors & ERROR_RECAL) == ERROR_RECAL)
			drive->special.b.recalibrate = 1;
		++rq->errors;
	}
}

/*
 * Issue a simple drive command
 * The drive must be selected beforehand.
 */
void ide_cmd(ide_drive_t *drive, byte cmd, byte nsect, ide_handler_t *handler)
{
	ide_set_handler (drive, handler, WAIT_CMD);
	OUT_BYTE(drive->ctl,IDE_CONTROL_REG);	/* clear nIEN */
	OUT_BYTE(nsect,IDE_NSECTOR_REG);
	OUT_BYTE(cmd,IDE_COMMAND_REG);
}

/*