freebsd-skq/sys/scsi/worm.c

/*
 * worm: Write Once device driver
 *
 * Copyright (C) 1995, HD Associates, Inc.
 * PO Box 276
 * Pepperell, MA 01463
 * 508 433 5266
 * dufault@hda.com
 *
 * This code is contributed to the University of California at Berkeley:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      $Id: worm.c,v 1.14 1995/12/08 11:19:07 julian Exp $
 */

/* XXX This is PRELIMINARY.
 *
 *     We need the "kern devconf" stuff, but I'm not
 *     going to add it until it is done in a simple way that provides
 *     base behavior in scsi_driver.c
 *
 *     Until Bruce finishes the slice stuff there will be no partitions.
 *     When it is finished I hope to hoist the partition code up into
 *     "scsi_driver" and use common code for all devices.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#ifdef DEVFS
#include <sys/devfsext.h>
#endif /*DEVFS*/
#include <scsi/scsi_all.h>
#include <scsi/scsiconf.h>
#include <scsi/scsi_disk.h>


struct scsi_data {
	struct buf_queue_head buf_queue;
	u_int32 n_blks;				/* Number of blocks (0 for bogus) */
	u_int32 blk_size;			/* Size of each blocks */
#ifdef	DEVFS
	void	*devfs_token;			/* more elaborate later */
#endif
};

static void wormstart(u_int32 unit, u_int32 flags);

static errval worm_open(dev_t dev, int flags, int fmt, struct proc *p,
	struct scsi_link *sc_link);
static errval worm_ioctl(dev_t dev, int cmd, caddr_t addr, int flag,
		struct proc *p, struct scsi_link *sc_link);
static errval worm_close(dev_t dev, int flag, int fmt, struct proc *p,
        struct scsi_link *sc_link);
static void worm_strategy(struct buf *bp, struct scsi_link *sc_link);

static	d_open_t	wormopen;
static	d_close_t	wormclose;
static	d_ioctl_t	wormioctl;
d_strategy_t	wormstrategy;

#define CDEV_MAJOR 62
static struct cdevsw worm_cdevsw = 
	{ wormopen,	wormclose,	rawread,	rawwrite,	/*62*/
	  wormioctl,	nostop,		nullreset,	nodevtotty,/* worm */
	  seltrue,	nommap,		wormstrategy };


SCSI_DEVICE_ENTRIES(worm)

static struct scsi_device worm_switch =
{
	NULL,
	wormstart,   /* we have a queue, and this is how we service it */
	NULL,
	NULL,
	"worm",
	0,
	{0, 0},
	SDEV_ONCE_ONLY,	/* Only one open allowed */
	wormattach,
	"Write-Once",
	wormopen,
	sizeof(struct scsi_data),
	T_WORM,
	0,
	0,
	worm_open,
	0,
	worm_close,
	worm_strategy,
};

static int worm_size(struct scsi_link *sc_link, int flags)
{
	int ret;
	struct scsi_data *worm = sc_link->sd;

	worm->n_blks = scsi_read_capacity(sc_link, &worm->blk_size,
					  flags);

	if(worm->blk_size == 0)
		/* XXX */
		worm->blk_size = 2048;
	if (worm->n_blks)
	{
		sc_link->flags |= SDEV_MEDIA_LOADED;
		ret = 1;
	}
	else
	{
		sc_link->flags &= ~SDEV_MEDIA_LOADED;
		ret = 0;
	}

	return ret;
}

static errval
wormattach(struct scsi_link *sc_link)
{
	struct scsi_data *worm = sc_link->sd;

	TAILQ_INIT(&worm->buf_queue);

	printf("- UNTESTED ");

	if (worm_size(sc_link, SCSI_NOSLEEP | SCSI_NOMASK) == 0)
		printf("- can't get capacity.");
	else
		printf("with %ld %ld byte blocks.",
				worm->n_blks, worm->blk_size);
#ifdef DEVFS

	worm->devfs_token = devfs_add_devsw( "/", "rworm", &worm_cdevsw, 0,
					DV_CHR, 0, 0, 0600);
#endif
	return 0;
}

/*
 * wormstart looks to see if there is a buf waiting for the device
 * and that the device is not already busy. If both are true,
 * It dequeues the buf and creates a scsi command to perform the
 * transfer required. The transfer request will call scsi_done
 * on completion, which will in turn call this routine again
 * so that the next queued transfer is performed.
 * The bufs are queued by the strategy routine (wormstrategy)
 *
 * This routine is also called after other non-queued requests
 * have been made of the scsi driver, to ensure that the queue
 * continues to be drained.
 * wormstart() is called at splbio
 *
 * XXX It looks like we need a "scsistart" to hoist common code up
 * into.  In particular, the removable media checking should be
 * handled in one place.
 */
static void
wormstart(unit, flags)
	u_int32	unit;
	u_int32 flags;
{
	struct scsi_link *sc_link = SCSI_LINK(&worm_switch, unit);
	struct scsi_data *worm = sc_link->sd;
	register struct buf *bp = 0;
	struct scsi_rw_big cmd;

	u_int32 lba;	/* Logical block address */
	u_int32 tl;		/* Transfer length */

	SC_DEBUG(sc_link, SDEV_DB2, ("wormstart "));

	/*
	 * We should reject all queued entries if SDEV_MEDIA_LOADED is not true.
	 */
	if (!(sc_link->flags & SDEV_MEDIA_LOADED)) {
		goto badnews;	/* no I/O.. media changed or something */
	}

	/*
	 * See if there is a buf to do and we are not already
	 * doing one
	 */
	while (sc_link->opennings != 0) {

		/* if a special awaits, let it proceed first */
		if (sc_link->flags & SDEV_WAITING) {
			sc_link->flags &= ~SDEV_WAITING;
			wakeup(sc_link);
			return;
		}

		bp = worm->buf_queue.tqh_first;
		if (bp == NULL) {	/* yes, an assign */
			return;
		}
		TAILQ_REMOVE( &worm->buf_queue, bp, b_act);

		/*
		 *  Fill out the scsi command
		 */
		bzero(&cmd, sizeof(cmd));
		if ((bp->b_flags & B_READ) == B_WRITE) {
			cmd.op_code = WRITE_BIG;
			flags |= SCSI_DATA_OUT;
		} else {
			cmd.op_code = READ_BIG;
			flags |= SCSI_DATA_IN;
		}


		lba = bp->b_blkno / (worm->blk_size / DEV_BSIZE);
		tl = bp->b_bcount / worm->blk_size;

		scsi_uto4b(lba, &cmd.addr_3);
		scsi_uto2b(tl, &cmd.length2);

		/*
		 * go ask the adapter to do all this for us
		 */
		if (scsi_scsi_cmd(sc_link,
			(struct scsi_generic *) &cmd,
			sizeof(cmd),
			(u_char *) bp->b_un.b_addr,
			bp->b_bcount,
			0,	/* can't retry a read on a tape really */
			100000,
			bp,
			flags | SCSI_NOSLEEP) == SUCCESSFULLY_QUEUED) {
		} else {
			printf("worm%ld: oops not queued\n", unit);
			if (bp) {
				bp->b_flags |= B_ERROR;
				bp->b_error = EIO;
				biodone(bp);
			}
		}
	} /* go back and see if we can cram more work in.. */
badnews:
}

static void
worm_strategy(struct buf *bp, struct scsi_link *sc_link)
{
	struct buf **dp;
	unsigned char unit;
	u_int32 opri;
	struct scsi_data *worm;

	unit = minor((bp->b_dev));
	worm = sc_link->sd;

	/* XXX: Can't we move this check up to "scsi_strategy"?
	 */
	if (!(sc_link->flags & SDEV_MEDIA_LOADED) ||
	bp->b_blkno > worm->n_blks ||
	bp->b_bcount & (worm->blk_size - 1)) {
		bp->b_error = EIO;
		bp->b_flags |= B_ERROR;
		biodone(bp);
		return;
	}

	opri = splbio();

	/*
	 * Use a bounce buffer if necessary
	 * XXX: How can we move this up?
	 */
#ifdef BOUNCE_BUFFERS
	if (sc_link->flags & SDEV_BOUNCE)
		vm_bounce_alloc(bp);
#endif

	/*
	 * Place it in the queue of activities for this device
	 * at the end.
	 */
	TAILQ_INSERT_TAIL(&worm->buf_queue, bp, b_act);

	wormstart(unit, 0);

	splx(opri);
	return;
}

/*
 * Open the device.  XXX: I'm completely guessing at this sequence.
 */
static int
worm_open(dev_t dev, int flags, int fmt, struct proc *p,
struct scsi_link *sc_link)
{
	if (sc_link->flags & SDEV_OPEN)
		return EBUSY;

	/*
	 * Check that it is still responding and ok.
	 * if the media has been changed this will result in a
	 * "unit attention" error which the error code will
	 * disregard because the SDEV_OPEN flag is not yet set
	 *
	 * XXX This should REALLY be hoisted up.  As soon as Bruce
	 * finishes that slice stuff. (Add a different flag,
	 * and then do a "scsi_test_unit_ready" with the "ignore
	 * unit attention" thing set.  Then all this replicated
	 * test unit ready code can be pulled up.
	 */
	scsi_test_unit_ready(sc_link, SCSI_SILENT);

	/*
	 * Next time actually take notice of error returns
	 */
	sc_link->flags |= SDEV_OPEN;	/* unit attn errors are now errors */

	if (scsi_test_unit_ready(sc_link, SCSI_SILENT) != 0) {
		SC_DEBUG(sc_link, SDEV_DB3, ("not ready\n"));
		sc_link->flags &= ~SDEV_OPEN;
		return ENXIO;
	}

	scsi_start_unit(sc_link, SCSI_SILENT);

	scsi_prevent(sc_link, PR_PREVENT, SCSI_SILENT);

	if (worm_size(sc_link, 0) == 0) {
		scsi_stop_unit(sc_link, 0, SCSI_SILENT);
		scsi_prevent(sc_link, PR_ALLOW, SCSI_SILENT);
		sc_link->flags &= ~SDEV_OPEN;
		return ENXIO;
	}

	return 0;
}

static int
worm_close(dev_t dev, int flag, int fmt, struct proc *p,
        struct scsi_link *sc_link)
{
	scsi_stop_unit(sc_link, 0, SCSI_SILENT);
	scsi_prevent(sc_link, PR_ALLOW, SCSI_SILENT);
	sc_link->flags &= ~SDEV_OPEN;

	return 0;
}

static worm_devsw_installed = 0;

static void
worm_drvinit(void *unused)
{
	dev_t dev;

	if( ! worm_devsw_installed ) {
		dev = makedev(CDEV_MAJOR,0);
		cdevsw_add(&dev,&worm_cdevsw,NULL);
		worm_devsw_installed = 1;
    	}
}

SYSINIT(wormdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,worm_drvinit,NULL)