scsi-linux-sg.c

创建一个符合iso-9660标准的iso文件系统

	int	f;
	int	tmo;
{
	tmo *= HZ;
	if (tmo)
		tmo += HZ/2;

	if (ioctl(f, SG_SET_TIMEOUT, &tmo) < 0)
		comerr("Cannot set SG_SET_TIMEOUT.\n");
}

/*
 * Get misaligned int.
 * Needed for all recent processors (sparc/ppc/alpha)
 * because the /dev/sg design forces us to do misaligned
 * reads of integers.
 */
#ifdef	MISALIGN
LOCAL int
scsi_getint(ip)
	int	*ip;
{
		 int	ret;
	register char	*cp = (char *)ip;
	register char	*tp = (char *)&ret;
	register int	i;

	for (i = sizeof(int); --i >= 0; )
		*tp++ = *cp++;
	
	return (ret);
}
#define	GETINT(a)	scsi_getint(&(a))
#else
#define	GETINT(a)	(a)
#endif

#ifdef	SG_IO
LOCAL int
scsi_send(scgp, f, sp)
	SCSI		*scgp;
	int		f;
	struct scg_cmd	*sp;
{
	int		ret;
	sg_io_hdr_t	sg_io;

	if (f < 0) {
		sp->error = SCG_FATAL;
		sp->ux_errno = EIO;
		return (0);
	}
	if (scglocal(scgp)->isold > 0) {
		return (scsi_rwsend(scgp, f, sp));
	}
	fillbytes((caddr_t)&sg_io, sizeof(sg_io), '\0');

	sg_io.interface_id = 'S';

	if (sp->flags & SCG_RECV_DATA) {
		sg_io.dxfer_direction = SG_DXFER_FROM_DEV;
	} else if (sp->size > 0) {
		sg_io.dxfer_direction = SG_DXFER_TO_DEV;
	} else {
		sg_io.dxfer_direction = SG_DXFER_NONE;
	}
	sg_io.cmd_len = sp->cdb_len;
	if (sp->sense_len > SG_MAX_SENSE)
		sg_io.mx_sb_len = SG_MAX_SENSE;
	else
		sg_io.mx_sb_len = sp->sense_len;
	sg_io.dxfer_len = sp->size;
	sg_io.dxferp = sp->addr;
	sg_io.cmdp = sp->cdb.cmd_cdb;
	sg_io.sbp = sp->u_sense.cmd_sense;
	sg_io.timeout = sp->timeout*1000;
	sg_io.flags |= SG_FLAG_DIRECT_IO;

	ret = ioctl(f, SG_IO, &sg_io);
	if (scgp->debug)
		printf("ioctl ret: %d\n", ret);

	if (ret < 0) {
		sp->ux_errno = geterrno();
		/*
		 * Check if SCSI command cound not be send at all.
		 */
		if (sp->ux_errno == EINVAL && scglocal(scgp)->isold < 0) {
			scglocal(scgp)->isold = 1;
			return (scsi_rwsend(scgp, f, sp));
		}
		if (sp->ux_errno == ENOTTY || sp->ux_errno == ENXIO ||
		    sp->ux_errno == EINVAL || sp->ux_errno == EACCES) {
			return (-1);
		}
	}

	sp->u_scb.cmd_scb[0] = sg_io.status;
	sp->sense_count = sg_io.sb_len_wr;

	if (scgp->debug)
		printf("host_status: %02X driver_status: %02X\n",
				sg_io.host_status, sg_io.driver_status);

	switch (sg_io.host_status) {

	case DID_OK:
			if ((sg_io.driver_status & DRIVER_SENSE) != 0)
				sp->error = SCG_RETRYABLE;
			break;

	case DID_NO_CONNECT:	/* Arbitration won, retry NO_CONNECT? */
	case DID_BAD_TARGET:
			sp->error = SCG_FATAL;
			break;
	
	case DID_TIME_OUT:
			sp->error = SCG_TIMEOUT;
			break;

	default:
			sp->error = SCG_RETRYABLE;
			break;
	}
	if (sp->error && sp->ux_errno == 0)
		sp->ux_errno = EIO;

	sp->resid = sg_io.resid;
	return (0);
}
#else
#	define	scsi_rwsend	scsi_send
#endif

LOCAL int
scsi_rwsend(scgp, f, sp)
	SCSI		*scgp;
	int		f;
	struct scg_cmd	*sp;
{
	struct sg_rq	*sgp;
	struct sg_rq	*sgp2;
	int	i;
	int	pack_len;
	int	reply_len;
	int	amt = sp->cdb_len;
	struct sg_rq {
		struct sg_header	hd;
		unsigned char		buf[MAX_DMA_LINUX+SCG_MAX_CMD];
	} sg_rq;
#ifdef	SG_GET_BUFSIZE		/* We may use a 'sg' version 2 driver	*/
	char	driver_byte;
	char	host_byte;
	char	msg_byte;
	char	status_byte;
#endif

	if (f < 0) {
		sp->error = SCG_FATAL;
		sp->ux_errno = EIO;
		return (0);
	}
#ifdef	USE_PG
	if (scgp->scsibus == scglocal(scgp)->pgbus)
		return (pg_send(scgp, f, sp));
#endif
	if (sp->timeout != scgp->deftimeout)
		sg_settimeout(f, sp->timeout);


	sgp2 = sgp = &sg_rq;
	if (sp->addr == scglocal(scgp)->SCSIbuf) {
		sgp = (struct sg_rq *)
			(scglocal(scgp)->SCSIbuf - (sizeof(struct sg_header) + amt));
		sgp2 = (struct sg_rq *)
			(scglocal(scgp)->SCSIbuf - (sizeof(struct sg_header)));
	} else {
		if (scgp->debug) {
			printf("DMA addr: 0x%8.8lX size: %d - using copy buffer\n",
				(long)sp->addr, sp->size);
		}
		if (sp->size > (int)(sizeof(sg_rq.buf) - SCG_MAX_CMD)) {

			if (scglocal(scgp)->xbuf == NULL) {
				scglocal(scgp)->xbufsize = scgp->maxbuf;
				scglocal(scgp)->xbuf =
					malloc(scglocal(scgp)->xbufsize +
						SCG_MAX_CMD +
						sizeof(struct sg_header));
				if (scgp->debug) {
					printf("Allocted DMA copy buffer, addr: 0x%8.8lX size: %ld\n",
						(long)scglocal(scgp)->xbuf,
						scgp->maxbuf);
				}
			}
			if (scglocal(scgp)->xbuf == NULL ||
				sp->size > scglocal(scgp)->xbufsize) {
				errno = ENOMEM;
				return (-1);
			}
			sgp2 = sgp = (struct sg_rq *)scglocal(scgp)->xbuf;
		}
	}

	/*
	 * This is done to avoid misaligned access of sgp->some_int
	 */
	pack_len = sizeof(struct sg_header) + amt;
	reply_len = sizeof(struct sg_header);
	if (sp->flags & SCG_RECV_DATA) {
		reply_len += sp->size;
	} else {
		pack_len += sp->size;
	}

#ifdef	MISALIGN
	/*
	 * sgp->some_int may be misaligned if (sp->addr == SCSIbuf)
	 * This is no problem on Intel porocessors, however
	 * all other processors don't like it.
	 * sizeof(struct sg_header) + amt is usually not a multiple of
	 * sizeof(int). For this reason, we fill in the values into sg_rq
	 * which is always corectly aligned and then copy it to the real
	 * location if this location differs from sg_rq.
	 * Never read/write directly to sgp->some_int !!!!!
	 */
	fillbytes((caddr_t)&sg_rq, sizeof(struct sg_header), '\0');

	sg_rq.hd.pack_len = pack_len;
	sg_rq.hd.reply_len = reply_len;
	sg_rq.hd.pack_id = scglocal(scgp)->pack_id++;
/*	sg_rq.hd.result = 0;	not needed because of fillbytes() */

	if ((caddr_t)&sg_rq != (caddr_t)sgp)
		movebytes((caddr_t)&sg_rq, (caddr_t)sgp, sizeof(struct sg_header));
#else
	fillbytes((caddr_t)sgp, sizeof(struct sg_header), '\0');

	sgp->hd.pack_len = pack_len;
	sgp->hd.reply_len = reply_len;
	sgp->hd.pack_id = scglocal(scgp)->pack_id++;
/*	sgp->hd.result = 0;	not needed because of fillbytes() */
#endif
	if (amt == 12)
		sgp->hd.twelve_byte = 1;


	for (i = 0; i < amt; i++ ) {
		sgp->buf[i] = sp->cdb.cmd_cdb[i];;
	}
	if (!(sp->flags & SCG_RECV_DATA)) {
		if ((void *)sp->addr != (void *)&sgp->buf[amt])
			movebytes(sp->addr, &sgp->buf[amt], sp->size);
		amt += sp->size;
	}
#ifdef	SG_GET_BUFSIZE
	sgp->hd.want_new  = 1;			/* Order new behaviour	*/
	sgp->hd.cdb_len	  = sp->cdb_len;	/* Set CDB length	*/
	if (sp->sense_len > SG_MAX_SENSE)
		sgp->hd.sense_len = SG_MAX_SENSE;
	else
		sgp->hd.sense_len = sp->sense_len;
#endif
	i = sizeof(struct sg_header) + amt;
	if ((amt = write(f, sgp, i)) < 0) {			/* write */
		sg_settimeout(f, scgp->deftimeout);
		return (-1);
	} else if (amt != i) {
		errmsg("scsi_send(%s) wrote %d bytes (expected %d).\n",
						scgp->cmdname, amt, i);
	}

	if (sp->addr == scglocal(scgp)->SCSIbuf) {
		movebytes(sgp, sgp2, sizeof(struct sg_header));
		sgp = sgp2;
	}
	sgp->hd.sense_buffer[0] = 0;
	if ((amt = read(f, sgp, reply_len)) < 0) {		/* read */
		sg_settimeout(f, scgp->deftimeout);
		return (-1);
	}

	if (sp->flags & SCG_RECV_DATA && ((void *)sgp->buf != (void *)sp->addr)) {
		movebytes(sgp->buf, sp->addr, sp->size);
	}
	sp->ux_errno = GETINT(sgp->hd.result);		/* Unaligned read */
	sp->error = SCG_NO_ERROR;

#ifdef	SG_GET_BUFSIZE
	if (sgp->hd.grant_new) {
		sp->sense_count = sgp->hd.sense_len;
		pack_len    = GETINT(sgp->hd.sg_cmd_status);	/* Unaligned read */
		driver_byte = (pack_len  >> 24) & 0xFF;
		host_byte   = (pack_len  >> 16) & 0xFF;
		msg_byte    = (pack_len  >> 8) & 0xFF;
		status_byte =  pack_len  & 0xFF;

		switch (host_byte) {

		case DID_OK:
				if ((driver_byte & DRIVER_SENSE ||
				    sgp->hd.sense_buffer[0] != 0)
							&& status_byte == 0) {
					/*
					 * The Linux SCSI system up to 2.1.xx
					 * trashes the status byte in the
					 * kernel. This is true at least for
					 * ide-scsi emulation. Until this gets
					 * fixed, we need this hack.
					 */
					sp->error = SCG_RETRYABLE;
					status_byte = ST_CHK_COND;
					if (sgp->hd.sense_len == 0)
						sgp->hd.sense_len = SG_MAX_SENSE;
				}
				break;

		case DID_NO_CONNECT:	/* Arbitration won, retry NO_CONNECT? */
		case DID_BAD_TARGET:
				sp->error = SCG_FATAL;
				break;
	
		case DID_TIME_OUT:
				sp->error = SCG_TIMEOUT;
				break;

		default:
				sp->error = SCG_RETRYABLE;

				if ((driver_byte & DRIVER_SENSE ||
				    sgp->hd.sense_buffer[0] != 0)
							&& status_byte == 0)
					status_byte = ST_CHK_COND;
				if (status_byte != 0 && sgp->hd.sense_len == 0)
					sgp->hd.sense_len = SG_MAX_SENSE;
				break;

		}
		if ((host_byte != DID_OK || status_byte != 0) && sp->ux_errno == 0)
			sp->ux_errno = EIO;
		sp->u_scb.cmd_scb[0] = status_byte;
		if (status_byte & ST_CHK_COND) {
			sp->sense_count = sgp->hd.sense_len;
			movebytes(sgp->hd.sense_buffer, sp->u_sense.cmd_sense, sp->sense_count);
		}
	} else
#endif
	{
		if (GETINT(sgp->hd.result) == EBUSY) {	/* Unaligned read */
			struct timeval to;

			to.tv_sec = sp->timeout;
			to.tv_usec = 500000;
			scsitimes(scgp);

			if (scgp->cmdstop->tv_sec < to.tv_sec ||
			    (scgp->cmdstop->tv_sec == to.tv_sec &&
				scgp->cmdstop->tv_usec < to.tv_usec)) {

				sp->ux_errno = 0;
				sp->error = SCG_TIMEOUT;	/* a timeout */
			} else {
				sp->error = SCG_RETRYABLE;	/* may be BUS_BUSY */
			}
		}

		if (sp->flags & SCG_RECV_DATA)
			sp->resid = (sp->size + sizeof(struct sg_header)) - amt;
		else
			sp->resid = 0;	/* sg version1 cannot return DMA resid count */

		if (sgp->hd.sense_buffer[0] != 0) {
			sp->error = SCG_RETRYABLE;
			sp->scb.chk = 1;
			sp->sense_count = SG_MAX_SENSE;
			movebytes(sgp->hd.sense_buffer, sp->u_sense.cmd_sense, sp->sense_count);
			if (sp->ux_errno == 0)
				sp->ux_errno = EIO;
		}
	}

	if (scgp->verbose > 0 && scgp->debug) {
#ifdef	SG_GET_BUFSIZE
		printf("status: 0x%08X pack_len: %d, reply_len: %d pack_id: %d result: %d wn: %d gn: %d cdb_len: %d sense_len: %d sense[0]: %02X\n",
				GETINT(sgp->hd.sg_cmd_status),
				GETINT(sgp->hd.pack_len),
				GETINT(sgp->hd.reply_len),
				GETINT(sgp->hd.pack_id),
				GETINT(sgp->hd.result),
				sgp->hd.want_new,
				sgp->hd.grant_new,
				sgp->hd.cdb_len,
				sgp->hd.sense_len,	
				sgp->hd.sense_buffer[0]);
#else
		printf("pack_len: %d, reply_len: %d pack_id: %d result: %d sense[0]: %02X\n",
				GETINT(sgp->hd.pack_len),
				GETINT(sgp->hd.reply_len),
				GETINT(sgp->hd.pack_id),
				GETINT(sgp->hd.result),
				sgp->hd.sense_buffer[0]);
#endif
#ifdef	DEBUG
		printf("sense: ");
		for (i=0; i < 16; i++)
			printf("%02X ", sgp->hd.sense_buffer[i]);
		printf("\n");
#endif
	}

	if (sp->timeout != scgp->deftimeout)
		sg_settimeout(f, scgp->deftimeout);
	return 0;
}