/*
 *	Interface for the Linux PARIDE implementation.
 *
 *	We emulate the functionality of the scg driver, via the pg driver.
 *
 *	Copyright (c) 1997  J. Schilling
 *	Copyright (c) 1998  Grant R. Guenther	<grant@torque.net>
 *			    Under the terms of the GNU public license.
 */

#include <linux/pg.h>

#define	MAX_SCG		4	/* Max # of SCSI controllers */
#define	MAX_TGT		8
#define	MAX_LUN		8

LOCAL   char	*SCSIbuf = (char *)-1;

LOCAL	short	scgfiles[MAX_SCG][MAX_TGT][MAX_LUN];

LOCAL	int	do_scsi_cmd	__PR((int f, struct scg_cmd *sp));
LOCAL	int	do_scsi_sense	__PR((int f, struct scg_cmd *sp));
LOCAL	int	scsi_send	__PR((int f, struct scg_cmd *sp));


EXPORT
int scsi_open()
{
	register int	f;
	register int	b;
	register int	t;
	register int	l;
	register int	nopen = 0;
	char		devname[32];

	
	for (b=0; b < MAX_SCG; b++) {
		for (t=0; t < MAX_TGT; t++) {
			for (l=0; l < MAX_LUN ; l++)
				scgfiles[b][t][l] = (short)-1;
		}
	}

	if (scsibus >= 0 && target >= 0 && lun >= 0) {	
		if (scsibus >= MAX_SCG || target >= MAX_TGT || lun >= MAX_LUN)
			return (-1);

		sprintf(devname, "/dev/pg%d", target);
		f = open(devname, 2);
		if (f < 0) {
			comerr("Cannot open '%s'.\n",devname);
			return 0;
		}
		scgfiles[scsibus][target][lun] = f;
		return 1;
	} else {
		scsibus = 0; lun = 0;
		for(target=0;target<MAX_TGT;target++) {
			sprintf(devname, "/dev/pg%d", target);
                	f = open(devname, 2);
			if (f >= 0) {
				scgfiles[scsibus][target][lun] = f;
				nopen++;
			}
		}
	}
	return (nopen);
}

LOCAL long
scsi_maxdma()
{
	return (PG_MAX_DATA);
}

EXPORT void *
scsi_getbuf(amt)
	long	amt;
{
        char    *ret;

        if (scg_maxdma == 0)
                scg_maxdma = scsi_maxdma();

        if (amt <= 0 || amt > scg_maxdma)
                return ((void *)0);
        if (debug)
                printf("scsi_getbuf: %ld bytes\n", amt);

        ret = valloc((size_t)(amt+getpagesize()));
        if (ret == NULL)
                return (ret);
        ret += getpagesize();
        SCSIbuf = ret;
        return ((void *)ret);

}

EXPORT
BOOL scsi_havebus(busno)
	int	busno;
{
	register int	t;
	register int	l;

	if (busno < 0 || busno >= MAX_SCG)
		return (FALSE);

	for (t=0; t < MAX_TGT; t++) {
		for (l=0; l < MAX_LUN ; l++)
			if (scgfiles[busno][t][l] >= 0)
				return (TRUE);
	}
	return (FALSE);
}

EXPORT
int scsi_fileno(busno, tgt, tlun)
	int	busno;
	int	tgt;
	int	tlun;
{
	if (busno < 0 || busno >= MAX_SCG ||
	    tgt < 0 || tgt >= MAX_TGT ||
	    tlun < 0 || tlun >= MAX_LUN)
		return (-1);

	return ((int)scgfiles[busno][tgt][tlun]);
}

EXPORT
int scsireset()
{
	int	f = scsi_fileno(scsibus, target, lun);

	struct pg_write_hdr hdr = {PG_MAGIC,PG_RESET,0};

	return (write(f,(char *)&hdr,sizeof(hdr)));

}

#ifndef MAX
#define MAX(a,b)	((a)>(b)?(a):(b))
#endif

#define	RHSIZE	sizeof(struct pg_read_hdr)
#define WHSIZE  sizeof(struct pg_write_hdr)
#define LEAD	MAX(RHSIZE,WHSIZE)

LOCAL int
do_scsi_cmd(f, sp)
	int		f;
	struct scg_cmd	*sp;
{

	char	local[LEAD+PG_MAX_DATA];
	int	use_local, i, r;
	int	inward = (sp->flags & SCG_RECV_DATA);

	struct pg_write_hdr *whp;
	struct pg_read_hdr  *rhp;
	char		    *dbp;

	if (sp->cdb_len > 12)
		comerrno(EX_BAD, "Can't do %d byte command.\n", sp->cdb_len);

	if (sp->addr == SCSIbuf) {
		use_local = 0; 
		dbp = sp->addr;
	} else {
		use_local = 1;
		dbp = &local[LEAD];
		if (!inward) 
			movebytes(sp->addr,dbp,sp->size);
	}

	whp = (struct pg_write_hdr *)(dbp - WHSIZE);
	rhp = (struct pg_read_hdr *)(dbp - RHSIZE);

	whp->magic   = PG_MAGIC;
	whp->func    = PG_COMMAND;
	whp->dlen    = sp->size;
	whp->timeout = sp->timeout;

	for(i=0;i<sp->cdb_len;i++)
		whp->packet[i] = sp->cdb.cmd_cdb[i];

	i = WHSIZE;
	if (!inward) 
		i += sp->size;

	r = write(f,(char *)whp,i);

	if (r < 0) {				/* command was not sent */
		sp->ux_errno = geterrno();
		return -1;
	}

	if (r != i)
		errmsg("scsi_send(%s) wrote %d bytes (expected %d).\n",
			scsi_command,r,i);

	sp->ux_errno = 0;
	sp->sense_count = 0;

	r = read(f,(char *)rhp,RHSIZE+sp->size);

	if (r == -ETIME) {
		sp->error = SCG_TIMEOUT;
		return 0;
	}

	if (r < 0) {
		sp->error = SCG_FATAL;
		return -1;
	}
		
	i = rhp->dlen;

	if (use_local && inward)
		movebytes(dbp,sp->addr,i);

	sp->resid = sp->size - i;

	fillbytes(&sp->scb, sizeof(sp->scb), '\0');
        fillbytes(&sp->u_sense.cmd_sense, sizeof(sp->u_sense.cmd_sense), '\0');

	sp->error = SCG_NO_ERROR;
	i = rhp->scsi?2:0;
	sp->u_scb.cmd_scb[0] = i;
	if (i) 
		sp->error = SCG_RETRYABLE;

	return 0;

}

LOCAL int
do_scsi_sense(f, sp)
	int		f;
	struct scg_cmd	*sp;
{
        int             ret;
        struct scg_cmd  s_cmd;

        if (sp->sense_len > SCG_MAX_SENSE)
                sp->sense_len = SCG_MAX_SENSE;

        fillbytes((caddr_t)&s_cmd, sizeof(s_cmd), '\0');
        s_cmd.addr = sp->u_sense.cmd_sense;
        s_cmd.size = sp->sense_len;
        s_cmd.flags = SCG_RECV_DATA|SCG_DISRE_ENA;
        s_cmd.cdb_len = SC_G0_CDBLEN;
        s_cmd.sense_len = CCS_SENSE_LEN;
        s_cmd.target = target;
        s_cmd.cdb.g0_cdb.cmd = SC_REQUEST_SENSE;
        s_cmd.cdb.g0_cdb.lun = sp->cdb.g0_cdb.lun;
        s_cmd.cdb.g0_cdb.count = sp->sense_len;
        ret = do_scsi_cmd(f, &s_cmd);

        if (ret < 0)
                return (ret);

        sp->sense_count = sp->sense_len - s_cmd.resid;
        return (ret);

}

LOCAL int
scsi_send(f, sp)
	int		f;
	struct scg_cmd	*sp;
{
	int	ret;

	if (f < 0) {
		sp->error = SCG_FATAL;
		return (0);
	}
	ret = do_scsi_cmd(f, sp);
	if (ret < 0)
		return (ret);
	if (sp->u_scb.cmd_scb[0])
		ret = do_scsi_sense(f, sp);
	return (ret);
}

/* end of scsi-linux-pg.c */