ide-cd.c

2410的硬盘块设备源码

		}

		if (blen > thislen)
			blen = thislen;

		xferfunc(drive, ptr, blen);

		thislen -= blen;
		len -= blen;
		rq->data_len -= blen;

		if (rq->bio)
			end_that_request_chunk(rq, 1, blen);
		else
			rq->data += blen;
	}

	/*
	 * pad, if necessary
	 */
	if (len > 0) {
		while (len > 0) {
			int pad = 0;

			xferfunc(drive, &pad, sizeof(pad));
			len -= sizeof(pad);
		}
	}

	if (HWGROUP(drive)->handler != NULL)
		BUG();

	ide_set_handler(drive, cdrom_newpc_intr, rq->timeout, NULL);
	return ide_started;

end_request:
	if (!rq->data_len)
		post_transform_command(rq);

	spin_lock_irqsave(&ide_lock, flags);
	blkdev_dequeue_request(rq);
	end_that_request_last(rq);
	HWGROUP(drive)->rq = NULL;
	spin_unlock_irqrestore(&ide_lock, flags);
	return ide_stopped;
}

static ide_startstop_t cdrom_write_intr(ide_drive_t *drive)
{
	int stat, ireason, len, sectors_to_transfer, uptodate;
	struct cdrom_info *info = drive->driver_data;
	int dma_error = 0, dma = info->dma;
	u8 lowcyl = 0, highcyl = 0;

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

	/* Check for errors. */
	if (dma) {
		info->dma = 0;
		if ((dma_error = HWIF(drive)->ide_dma_end(drive))) {
			printk(KERN_ERR "ide-cd: write dma error\n");
			__ide_dma_off(drive);
		}
	}

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

	/*
	 * using dma, transfer is complete now
	 */
	if (dma) {
		if (dma_error)
			return ide_error(drive, "dma error", stat);

		ide_end_request(drive, 1, rq->nr_sectors);
		return ide_stopped;
	}

	/* Read the interrupt reason and the transfer length. */
	ireason = HWIF(drive)->INB(IDE_IREASON_REG);
	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 writing, complain.
		 * Otherwise, complete the command normally.
		 */
		uptodate = 1;
		if (rq->current_nr_sectors > 0) {
			printk(KERN_ERR "%s: write_intr: data underrun (%d blocks)\n",
			drive->name, rq->current_nr_sectors);
			uptodate = 0;
		}
		cdrom_end_request(drive, uptodate);
		return ide_stopped;
	}

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

	sectors_to_transfer = len / SECTOR_SIZE;

	/*
	 * now loop and write out the data
	 */
	while (sectors_to_transfer > 0) {
		int this_transfer;

		if (!rq->current_nr_sectors) {
			printk(KERN_ERR "ide-cd: write_intr: oops\n");
			break;
		}

		/*
		 * Figure out how many sectors we can transfer
		 */
		this_transfer = min_t(int, sectors_to_transfer, rq->current_nr_sectors);

		while (this_transfer > 0) {
			HWIF(drive)->atapi_output_bytes(drive, rq->buffer, SECTOR_SIZE);
			rq->buffer += SECTOR_SIZE;
			--rq->nr_sectors;
			--rq->current_nr_sectors;
			++rq->sector;
			--this_transfer;
			--sectors_to_transfer;
		}

		/*
		 * current buffer complete, move on
		 */
		if (rq->current_nr_sectors == 0 && rq->nr_sectors)
			cdrom_end_request(drive, 1);
	}

	/* re-arm handler */
	ide_set_handler(drive, &cdrom_write_intr, ATAPI_WAIT_PC, NULL);
	return ide_started;
}

static ide_startstop_t cdrom_start_write_cont(ide_drive_t *drive)
{
	struct request *rq = HWGROUP(drive)->rq;

#if 0	/* the immediate bit */
	rq->cmd[1] = 1 << 3;
#endif
	rq->timeout = ATAPI_WAIT_PC;

	return cdrom_transfer_packet_command(drive, rq, cdrom_write_intr);
}

static ide_startstop_t cdrom_start_write(ide_drive_t *drive, struct request *rq)
{
	struct cdrom_info *info = drive->driver_data;
	struct gendisk *g = info->disk;
	unsigned short sectors_per_frame = queue_hardsect_size(drive->queue) >> SECTOR_BITS;

	/*
	 * writes *must* be hardware frame aligned
	 */
	if ((rq->nr_sectors & (sectors_per_frame - 1)) ||
	    (rq->sector & (sectors_per_frame - 1))) {
		cdrom_end_request(drive, 0);
		return ide_stopped;
	}

	/*
	 * disk has become write protected
	 */
	if (g->policy) {
		cdrom_end_request(drive, 0);
		return ide_stopped;
	}

	/*
	 * for dvd-ram and such media, it's a really big deal to get
	 * big writes all the time. so scour the queue and attempt to
	 * remerge requests, often the plugging will not have had time
	 * to do this properly
	 */
	blk_attempt_remerge(drive->queue, rq);

	info->nsectors_buffered = 0;

	/* use dma, if possible. we don't need to check more, since we
	 * know that the transfer is always (at least!) frame aligned */
	info->dma = drive->using_dma ? 1 : 0;
	info->cmd = WRITE;

	info->devinfo.media_written = 1;

	/* Start sending the write request to the drive. */
	return cdrom_start_packet_command(drive, 32768, cdrom_start_write_cont);
}

static ide_startstop_t cdrom_do_newpc_cont(ide_drive_t *drive)
{
	struct request *rq = HWGROUP(drive)->rq;

	if (!rq->timeout)
		rq->timeout = ATAPI_WAIT_PC;

	return cdrom_transfer_packet_command(drive, rq, cdrom_newpc_intr);
}

static ide_startstop_t cdrom_do_block_pc(ide_drive_t *drive, struct request *rq)
{
	struct cdrom_info *info = drive->driver_data;

	rq->flags |= REQ_QUIET;

	info->dma = 0;
	info->cmd = 0;

	/*
	 * sg request
	 */
	if (rq->bio) {
		int mask = drive->queue->dma_alignment;
		unsigned long addr = (unsigned long) page_address(bio_page(rq->bio));

		info->cmd = rq_data_dir(rq);
		info->dma = drive->using_dma;

		/*
		 * check if dma is safe
		 *
		 * NOTE! The "len" and "addr" checks should possibly have
		 * separate masks.
		 */
		if ((rq->data_len & 15) || (addr & mask))
			info->dma = 0;
	}

	/* Start sending the command to the drive. */
	return cdrom_start_packet_command(drive, rq->data_len, cdrom_do_newpc_cont);
}

/****************************************************************************
 * cdrom driver request routine.
 */
static ide_startstop_t
ide_do_rw_cdrom (ide_drive_t *drive, struct request *rq, sector_t block)
{
	ide_startstop_t action;
	struct cdrom_info *info = drive->driver_data;

	if (blk_fs_request(rq)) {
		if (CDROM_CONFIG_FLAGS(drive)->seeking) {
			unsigned long elapsed = jiffies - info->start_seek;
			int stat = HWIF(drive)->INB(IDE_STATUS_REG);

			if ((stat & SEEK_STAT) != SEEK_STAT) {
				if (elapsed < IDECD_SEEK_TIMEOUT) {
					ide_stall_queue(drive, IDECD_SEEK_TIMER);
					return ide_stopped;
				}
				printk (KERN_ERR "%s: DSC timeout\n", drive->name);
			}
			CDROM_CONFIG_FLAGS(drive)->seeking = 0;
		}
		if ((rq_data_dir(rq) == READ) && IDE_LARGE_SEEK(info->last_block, block, IDECD_SEEK_THRESHOLD) && drive->dsc_overlap) {
			action = cdrom_start_seek(drive, block);
		} else {
			if (rq_data_dir(rq) == READ)
				action = cdrom_start_read(drive, block);
			else
				action = cdrom_start_write(drive, rq);
		}
		info->last_block = block;
		return action;
	} else if (rq->flags & (REQ_PC | REQ_SENSE)) {
		return cdrom_do_packet_command(drive);
	} else if (rq->flags & REQ_BLOCK_PC) {
		return cdrom_do_block_pc(drive, rq);
	} else if (rq->flags & REQ_SPECIAL) {
		/*
		 * right now this can only be a reset...
		 */
		cdrom_end_request(drive, 1);
		return ide_stopped;
	}

	blk_dump_rq_flags(rq, "ide-cd bad flags");
	cdrom_end_request(drive, 0);
	return ide_stopped;
}



/****************************************************************************
 * Ioctl handling.
 *
 * Routines which queue packet commands take as a final argument a pointer
 * to a request_sense struct.  If execution of the command results
 * in an error with a CHECK CONDITION status, this structure will be filled
 * with the results of the subsequent request sense command.  The pointer
 * can also be NULL, in which case no sense information is returned.
 */

#if ! STANDARD_ATAPI
static inline
int bin2bcd (int x)
{
	return (x%10) | ((x/10) << 4);
}


static inline
int bcd2bin (int x)
{
	return (x >> 4) * 10 + (x & 0x0f);
}

static
void msf_from_bcd (struct atapi_msf *msf)
{
	msf->minute = bcd2bin (msf->minute);
	msf->second = bcd2bin (msf->second);
	msf->frame  = bcd2bin (msf->frame);
}

#endif /* not STANDARD_ATAPI */


static inline
void lba_to_msf (int lba, byte *m, byte *s, byte *f)
{
	lba += CD_MSF_OFFSET;
	lba &= 0xffffff;  /* negative lbas use only 24 bits */
	*m = lba / (CD_SECS * CD_FRAMES);
	lba %= (CD_SECS * CD_FRAMES);
	*s = lba / CD_FRAMES;
	*f = lba % CD_FRAMES;
}


static inline
int msf_to_lba (byte m, byte s, byte f)
{
	return (((m * CD_SECS) + s) * CD_FRAMES + f) - CD_MSF_OFFSET;
}

static int cdrom_check_status(ide_drive_t *drive, struct request_sense *sense)
{
	struct request req;
	struct cdrom_info *info = drive->driver_data;
	struct cdrom_device_info *cdi = &info->devinfo;

	cdrom_prepare_request(drive, &req);

	req.sense = sense;
	req.cmd[0] = GPCMD_TEST_UNIT_READY;
	req.flags |= REQ_QUIET;

#if ! STANDARD_ATAPI
        /* the Sanyo 3 CD changer uses byte 7 of TEST_UNIT_READY to 
           switch CDs instead of supporting the LOAD_UNLOAD opcode   */

	req.cmd[7] = cdi->sanyo_slot % 3;
#endif /* not STANDARD_ATAPI */

	return cdrom_queue_packet_command(drive, &req);
}


/* Lock the door if LOCKFLAG is nonzero; unlock it otherwise. */
static int
cdrom_lockdoor(ide_drive_t *drive, int lockflag, struct request_sense *sense)
{
	struct request_sense my_sense;
	struct request req;
	int stat;

	if (sense == NULL)
		sense = &my_sense;

	/* If the drive cannot lock the door, just pretend. */
	if (CDROM_CONFIG_FLAGS(drive)->no_doorlock) {
		stat = 0;
	} else {
		cdrom_prepare_request(drive, &req);
		req.sense = sense;
		req.cmd[0] = GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL;
		req.cmd[4] = lockflag ? 1 : 0;
		stat = cdrom_queue_packet_command(drive, &req);
	}

	/* If we got an illegal field error, the drive
	   probably cannot lock the door. */
	if (stat != 0 &&
	    sense->sense_key == ILLEGAL_REQUEST &&
	    (sense->asc == 0x24 || sense->asc == 0x20)) {
		printk (KERN_ERR "%s: door locking not supported\n",
			drive->name);
		CDROM_CONFIG_FLAGS(drive)->no_doorlock = 1;
		stat = 0;
	}
	
	/* no medium, that's alright. */
	if (stat != 0 && sense->sense_key == NOT_READY && sense->asc == 0x3a)
		stat = 0;

	if (stat == 0)
		CDROM_STATE_FLAGS(drive)->door_locked = lockflag;

	return stat;
}


/* Eject the disk if EJECTFLAG is 0.
   If EJECTFLAG is 1, try to reload the disk. */
static int cdrom_eject(ide_drive_t *drive, int ejectflag,
		       struct request_sense *sense)