ide-cd.c

2410的硬盘块设备源码

	/* FIXME: for Virtual DMA we must check harder */
	HWIF(drive)->OUTB(info->dma, IDE_FEATURE_REG);
	HWIF(drive)->OUTB(0, IDE_IREASON_REG);
	HWIF(drive)->OUTB(0, IDE_SECTOR_REG);

	HWIF(drive)->OUTB(xferlen & 0xff, IDE_BCOUNTL_REG);
	HWIF(drive)->OUTB(xferlen >> 8  , IDE_BCOUNTH_REG);
	if (IDE_CONTROL_REG)
		HWIF(drive)->OUTB(drive->ctl, IDE_CONTROL_REG);
 
	if (CDROM_CONFIG_FLAGS (drive)->drq_interrupt) {
		/* packet command */
		ide_execute_command(drive, WIN_PACKETCMD, handler, ATAPI_WAIT_PC, cdrom_timer_expiry);
		return ide_started;
	} else {
		unsigned long flags;

		/* packet command */
		spin_lock_irqsave(&ide_lock, flags);
		hwif->OUTBSYNC(drive, WIN_PACKETCMD, IDE_COMMAND_REG);
		ndelay(400);
		spin_unlock_irqrestore(&ide_lock, flags);

		return (*handler) (drive);
	}
}

/* Send a packet command to DRIVE described by CMD_BUF and CMD_LEN.
   The device registers must have already been prepared
   by cdrom_start_packet_command.
   HANDLER is the interrupt handler to call when the command completes
   or there's data ready. */
/*
 * changed 5 parameters to 3 for dvd-ram
 * struct packet_command *pc; now packet_command_t *pc;
 */
#define ATAPI_MIN_CDB_BYTES 12
static ide_startstop_t cdrom_transfer_packet_command (ide_drive_t *drive,
					  struct request *rq,
					  ide_handler_t *handler)
{
	ide_hwif_t *hwif = drive->hwif;
	int cmd_len;
	struct cdrom_info *info = drive->driver_data;
	ide_startstop_t startstop;

	if (CDROM_CONFIG_FLAGS(drive)->drq_interrupt) {
		/* Here we should have been called after receiving an interrupt
		   from the device.  DRQ should how be set. */

		/* Check for errors. */
		if (cdrom_decode_status(drive, DRQ_STAT, NULL))
			return ide_stopped;
	} else {
		/* Otherwise, we must wait for DRQ to get set. */
		if (ide_wait_stat(&startstop, drive, DRQ_STAT,
				BUSY_STAT, WAIT_READY))
			return startstop;
	}

	/* Arm the interrupt handler. */
	ide_set_handler(drive, handler, rq->timeout, cdrom_timer_expiry);

	/* ATAPI commands get padded out to 12 bytes minimum */
	cmd_len = COMMAND_SIZE(rq->cmd[0]);
	if (cmd_len < ATAPI_MIN_CDB_BYTES)
		cmd_len = ATAPI_MIN_CDB_BYTES;

	/* Send the command to the device. */
	HWIF(drive)->atapi_output_bytes(drive, rq->cmd, cmd_len);

	/* Start the DMA if need be */
	if (info->dma)
		hwif->dma_start(drive);

	return ide_started;
}

/****************************************************************************
 * Block read functions.
 */

/*
 * Buffer up to SECTORS_TO_TRANSFER sectors from the drive in our sector
 * buffer.  Once the first sector is added, any subsequent sectors are
 * assumed to be continuous (until the buffer is cleared).  For the first
 * sector added, SECTOR is its sector number.  (SECTOR is then ignored until
 * the buffer is cleared.)
 */
static void cdrom_buffer_sectors (ide_drive_t *drive, unsigned long sector,
                                  int sectors_to_transfer)
{
	struct cdrom_info *info = drive->driver_data;

	/* Number of sectors to read into the buffer. */
	int sectors_to_buffer = min_t(int, sectors_to_transfer,
				     (SECTOR_BUFFER_SIZE >> SECTOR_BITS) -
				       info->nsectors_buffered);

	char *dest;

	/* If we couldn't get a buffer, don't try to buffer anything... */
	if (info->buffer == NULL)
		sectors_to_buffer = 0;

	/* If this is the first sector in the buffer, remember its number. */
	if (info->nsectors_buffered == 0)
		info->sector_buffered = sector;

	/* Read the data into the buffer. */
	dest = info->buffer + info->nsectors_buffered * SECTOR_SIZE;
	while (sectors_to_buffer > 0) {
		HWIF(drive)->atapi_input_bytes(drive, dest, SECTOR_SIZE);
		--sectors_to_buffer;
		--sectors_to_transfer;
		++info->nsectors_buffered;
		dest += SECTOR_SIZE;
	}

	/* Throw away any remaining data. */
	while (sectors_to_transfer > 0) {
		static char dum[SECTOR_SIZE];
		HWIF(drive)->atapi_input_bytes(drive, dum, sizeof (dum));
		--sectors_to_transfer;
	}
}

/*
 * Check the contents of the interrupt reason register from the cdrom
 * and attempt to recover if there are problems.  Returns  0 if everything's
 * ok; nonzero if the request has been terminated.
 */
static inline
int cdrom_read_check_ireason (ide_drive_t *drive, int len, int ireason)
{
	if (ireason == 2)
		return 0;
	else if (ireason == 0) {
		/* Whoops... The drive is expecting to receive data from us! */
		printk(KERN_ERR "%s: read_intr: Drive wants to transfer data the "
						"wrong way!\n", drive->name);

		/* Throw some data at the drive so it doesn't hang
		   and quit this request. */
		while (len > 0) {
			int dum = 0;
			HWIF(drive)->atapi_output_bytes(drive, &dum, sizeof (dum));
			len -= sizeof (dum);
		}
	} else  if (ireason == 1) {
		/* Some drives (ASUS) seem to tell us that status
		 * info is available. just get it and ignore.
		 */
		(void) HWIF(drive)->INB(IDE_STATUS_REG);
		return 0;
	} else {
		/* Drive wants a command packet, or invalid ireason... */
		printk(KERN_ERR "%s: read_intr: bad interrupt reason %x\n", drive->name,
								ireason);
	}

	cdrom_end_request(drive, 0);
	return -1;
}

/*
 * Interrupt routine.  Called when a read request has completed.
 */
static ide_startstop_t cdrom_read_intr (ide_drive_t *drive)
{
	int stat;
	int ireason, len, sectors_to_transfer, nskip;
	struct cdrom_info *info = drive->driver_data;
	u8 lowcyl = 0, highcyl = 0;
	int dma = info->dma, dma_error = 0;

	struct request *rq = HWGROUP(drive)->rq;

	/*
	 * handle dma case
	 */
	if (dma) {
		info->dma = 0;
		if ((dma_error = HWIF(drive)->ide_dma_end(drive)))
			__ide_dma_off(drive);
	}

	if (cdrom_decode_status(drive, 0, &stat))
		return ide_stopped;

	if (dma) {
		if (!dma_error) {
			ide_end_request(drive, 1, rq->nr_sectors);
			return ide_stopped;
		} else
			return ide_error(drive, "dma error", stat);
	}

	/* Read the interrupt reason and the transfer length. */
	ireason = HWIF(drive)->INB(IDE_IREASON_REG) & 0x3;
	lowcyl  = HWIF(drive)->INB(IDE_BCOUNTL_REG);
	highcyl = HWIF(drive)->INB(IDE_BCOUNTH_REG);

	len = lowcyl + (256 * highcyl);

	/* If DRQ is clear, the command has completed. */
	if ((stat & DRQ_STAT) == 0) {
		/* If we're not done filling the current buffer, complain.
		   Otherwise, complete the command normally. */
		if (rq->current_nr_sectors > 0) {
			printk (KERN_ERR "%s: cdrom_read_intr: data underrun (%d blocks)\n",
				drive->name, rq->current_nr_sectors);
			rq->flags |= REQ_FAILED;
			cdrom_end_request(drive, 0);
		} else
			cdrom_end_request(drive, 1);
		return ide_stopped;
	}

	/* Check that the drive is expecting to do the same thing we are. */
	if (cdrom_read_check_ireason (drive, len, ireason))
		return ide_stopped;

	/* Assume that the drive will always provide data in multiples
	   of at least SECTOR_SIZE, as it gets hairy to keep track
	   of the transfers otherwise. */
	if ((len % SECTOR_SIZE) != 0) {
		printk (KERN_ERR "%s: cdrom_read_intr: Bad transfer size %d\n",
			drive->name, len);
		if (CDROM_CONFIG_FLAGS(drive)->limit_nframes)
			printk (KERN_ERR "  This drive is not supported by this version of the driver\n");
		else {
			printk (KERN_ERR "  Trying to limit transfer sizes\n");
			CDROM_CONFIG_FLAGS(drive)->limit_nframes = 1;
		}
		cdrom_end_request(drive, 0);
		return ide_stopped;
	}

	/* The number of sectors we need to read from the drive. */
	sectors_to_transfer = len / SECTOR_SIZE;

	/* First, figure out if we need to bit-bucket
	   any of the leading sectors. */
	nskip = min_t(int, rq->current_nr_sectors - bio_cur_sectors(rq->bio), sectors_to_transfer);

	while (nskip > 0) {
		/* We need to throw away a sector. */
		static char dum[SECTOR_SIZE];
		HWIF(drive)->atapi_input_bytes(drive, dum, sizeof (dum));

		--rq->current_nr_sectors;
		--nskip;
		--sectors_to_transfer;
	}

	/* Now loop while we still have data to read from the drive. */
	while (sectors_to_transfer > 0) {
		int this_transfer;

		/* If we've filled the present buffer but there's another
		   chained buffer after it, move on. */
		if (rq->current_nr_sectors == 0 && rq->nr_sectors)
			cdrom_end_request(drive, 1);

		/* If the buffers are full, cache the rest of the data in our
		   internal buffer. */
		if (rq->current_nr_sectors == 0) {
			cdrom_buffer_sectors(drive, rq->sector, sectors_to_transfer);
			sectors_to_transfer = 0;
		} else {
			/* Transfer data to the buffers.
			   Figure out how many sectors we can transfer
			   to the current buffer. */
			this_transfer = min_t(int, sectors_to_transfer,
					     rq->current_nr_sectors);

			/* Read this_transfer sectors
			   into the current buffer. */
			while (this_transfer > 0) {
				HWIF(drive)->atapi_input_bytes(drive, rq->buffer, SECTOR_SIZE);
				rq->buffer += SECTOR_SIZE;
				--rq->nr_sectors;
				--rq->current_nr_sectors;
				++rq->sector;
				--this_transfer;
				--sectors_to_transfer;
			}
		}
	}

	/* Done moving data!  Wait for another interrupt. */
	ide_set_handler(drive, &cdrom_read_intr, ATAPI_WAIT_PC, NULL);
	return ide_started;
}

/*
 * Try to satisfy some of the current read request from our cached data.
 * Returns nonzero if the request has been completed, zero otherwise.
 */
static int cdrom_read_from_buffer (ide_drive_t *drive)
{
	struct cdrom_info *info = drive->driver_data;
	struct request *rq = HWGROUP(drive)->rq;
	unsigned short sectors_per_frame;

	sectors_per_frame = queue_hardsect_size(drive->queue) >> SECTOR_BITS;

	/* Can't do anything if there's no buffer. */
	if (info->buffer == NULL) return 0;

	/* Loop while this request needs data and the next block is present
	   in our cache. */
	while (rq->nr_sectors > 0 &&
	       rq->sector >= info->sector_buffered &&
	       rq->sector < info->sector_buffered + info->nsectors_buffered) {
		if (rq->current_nr_sectors == 0)
			cdrom_end_request(drive, 1);

		memcpy (rq->buffer,
			info->buffer +
			(rq->sector - info->sector_buffered) * SECTOR_SIZE,
			SECTOR_SIZE);
		rq->buffer += SECTOR_SIZE;
		--rq->current_nr_sectors;
		--rq->nr_sectors;
		++rq->sector;
	}

	/* If we've satisfied the current request,
	   terminate it successfully. */
	if (rq->nr_sectors == 0) {
		cdrom_end_request(drive, 1);
		return -1;
	}

	/* Move on to the next buffer if needed. */
	if (rq->current_nr_sectors == 0)
		cdrom_end_request(drive, 1);

	/* If this condition does not hold, then the kluge i use to
	   represent the number of sectors to skip at the start of a transfer
	   will fail.  I think that this will never happen, but let's be
	   paranoid and check. */
	if (rq->current_nr_sectors < bio_cur_sectors(rq->bio) &&
	    (rq->sector & (sectors_per_frame - 1))) {
		printk(KERN_ERR "%s: cdrom_read_from_buffer: buffer botch (%ld)\n",
			drive->name, (long)rq->sector);
		cdrom_end_request(drive, 0);
		return -1;
	}

	return 0;
}

/*
 * Routine to send a read packet command to the drive.
 * This is usually called directly from cdrom_start_read.
 * However, for drq_interrupt devices, it is called from an interrupt
 * when the drive is ready to accept the command.
 */
static ide_startstop_t cdrom_start_read_continuation (ide_drive_t *drive)
{
	struct request *rq = HWGROUP(drive)->rq;
	unsigned short sectors_per_frame;
	int nskip;

	sectors_per_frame = queue_hardsect_size(drive->queue) >> SECTOR_BITS;

	/* If the requested sector doesn't start on a cdrom block boundary,
	   we must adjust the start of the transfer so that it does,
	   and remember to skip the first few sectors.
	   If the CURRENT_NR_SECTORS field is larger than the size
	   of the buffer, it will mean that we're to skip a number
	   of sectors equal to the amount by which CURRENT_NR_SECTORS
	   is larger than the buffer size. */
	nskip = rq->sector & (sectors_per_frame - 1);
	if (nskip > 0) {
		/* Sanity check... */
		if (rq->current_nr_sectors != bio_cur_sectors(rq->bio) &&
			(rq->sector & (sectors_per_frame - 1))) {
			printk(KERN_ERR "%s: cdrom_start_read_continuation: buffer botch (%u)\n",
				drive->name, rq->current_nr_sectors);
			cdrom_end_request(drive, 0);
			return ide_stopped;
		}
		rq->current_nr_sectors += nskip;
	}

	/* Set up the command */
	rq->timeout = ATAPI_WAIT_PC;

	/* Send the command to the drive and return. */
	return cdrom_transfer_packet_command(drive, rq, &cdrom_read_intr);
}


#define IDECD_SEEK_THRESHOLD	(1000)			/* 1000 blocks */
#define IDECD_SEEK_TIMER	(5 * WAIT_MIN_SLEEP)	/* 100 ms */
#define IDECD_SEEK_TIMEOUT	(2 * WAIT_CMD)		/* 20 sec */

static ide_startstop_t cdrom_seek_intr (ide_drive_t *drive)
{
	struct cdrom_info *info = drive->driver_data;
	int stat;
	static int retry = 10;

	if (cdrom_decode_status(drive, 0, &stat))
		return ide_stopped;
	CDROM_CONFIG_FLAGS(drive)->seeking = 1;

	if (retry && time_after(jiffies, info->start_seek + IDECD_SEEK_TIMER)) {
		if (--retry == 0) {
			/*
			 * this condition is far too common, to bother
			 * users about it
			 */
			/* printk("%s: disabled DSC seek overlap\n", drive->name);*/ 
			drive->dsc_overlap = 0;
		}
	}
	return ide_stopped;
}

static ide_startstop_t cdrom_start_seek_continuation (ide_drive_t *drive)