xref: /csrg-svn/sys/vax/stand/hp.c (revision 10608)
1*10608Ssam /*	hp.c	4.4	83/01/23	*/
210334Shelge 
310334Shelge /*
410334Shelge  * RP??/RM?? disk driver
510334Shelge  * with ECC handling and bad block forwarding.
610334Shelge  * Also supports header io operations and
710334Shelge  * commands to write check header and data.
810334Shelge  */
910334Shelge 
1010334Shelge #include "../h/param.h"
1110334Shelge #include "../h/inode.h"
1210334Shelge #include "../h/fs.h"
1310334Shelge #include "../h/dkbad.h"
1410334Shelge 
1510334Shelge #include "../vax/pte.h"
1610334Shelge #include "../vaxmba/hpreg.h"
1710334Shelge #include "../vaxmba/mbareg.h"
1810334Shelge 
1910334Shelge #include "saio.h"
2010334Shelge #include "savax.h"
2110334Shelge 
2210334Shelge #define	MASKREG(reg)	((reg)&0xffff)
2310334Shelge 
2410334Shelge #define MAXBADDESC	126
2510334Shelge #define SECTSIZ 	512	/* sector size in bytes */
2610334Shelge #define HDRSIZ		4	/* number of bytes in sector header */
2710334Shelge #define MAXECC		5	/* the maximum number of bad bits accepted in
2810334Shelge 				 * an ecc error when F_ECCLM is set */
2910334Shelge 
3010334Shelge char	hp_type[MAXNMBA*8] = { 0 };
3110334Shelge 
3210334Shelge /* THIS SHOULD BE READ IN OFF THE PACK, PER DRIVE */
3310334Shelge short	hp6_off[8] =	{ 0, 38, 0, -1, -1, -1, 118, -1 };
3410334Shelge short	rm3_off[8] =	{ 0, 100, 0, -1, -1, -1, 310, -1 };
3510334Shelge short	rm5_off[8] =	{ 0, 27, 0, 562, 589, 681, 562, 82 };
3610334Shelge short	rm80_off[8] =	{ 0, 37, 0, -1, -1, -1, 115, 305 };
3710334Shelge short	hp7_off[8] = 	{ 0, 10, 0, 330, 340, 500, 330, 50 };
3810334Shelge short	ml_off[8] =	{ 0, -1, -1, -1, -1, -1, -1, -1 };
3910334Shelge short	si9775_off[8] =	{ 0, 13, 0, -1, -1, -1, 40, 441 };
4010334Shelge short	si9730_off[8] = { 0, 50, 0, -1, -1, -1, -1, 155 };
4110334Shelge short	hpam_off[8] =	{ 0, 32, 0, 668, 723, 778, 668, 98 };
4210334Shelge /* END SHOULD BE READ IN */
4310334Shelge 
4410334Shelge short	hptypes[] =
4510334Shelge     { MBDT_RM03, MBDT_RM05, MBDT_RP06, MBDT_RM80, MBDT_RP05, MBDT_RP07,
4610334Shelge       MBDT_ML11A, MBDT_ML11B, -1/*9755*/, -1/*9730*/, -1/*Capr*/, MBDT_RM02, 0};
4710334Shelge 
4810334Shelge #define RP06 (hptypes[UNITTODRIVE(unit)] <= MBDT_RP06)
4910334Shelge #define ML11 (hptypes[UNITTODRIVE(unit)] <= MBDT_ML11A)
5010334Shelge #define RM80 (hptypes[UNITTODRIVE(unit)] <= MBDT_RM80)
5110334Shelge 
5210334Shelge u_char	hp_offset[16] = {
5310334Shelge     HPOF_P400, HPOF_M400, HPOF_P400, HPOF_M400,
5410334Shelge     HPOF_P800, HPOF_M800, HPOF_P800, HPOF_M800,
5510334Shelge     HPOF_P1200, HPOF_M1200, HPOF_P1200, HPOF_M1200,
5610334Shelge     0, 0, 0, 0,
5710334Shelge };
5810334Shelge 
5910353Shelge struct st hpst[] = {
6010334Shelge 	32,	5,	32*5,	823,	rm3_off,	/* RM03 */
6110334Shelge 	32,	19,	32*19,	823,	rm5_off,	/* RM05 */
6210334Shelge 	22,	19,	22*19,	815,	hp6_off,	/* RP06 */
6310334Shelge 	31,	14, 	31*14,	559,	rm80_off,	/* RM80 */
6410334Shelge 	22,	19,	22*19,	411,	hp6_off,	/* RP06 */
6510334Shelge 	50,	32,	50*32,	630,	hp7_off,	/* RP07 */
6610334Shelge 	1,	1,	1,	1,	ml_off,		/* ML11A */
6710334Shelge 	1,	1,	1,	1,	ml_off,		/* ML11B */
6810334Shelge 	32,	40,	32*40,	843,	si9775_off,	/* 9775 */
6910334Shelge 	32,	10,	32*10,	823,	si9730_off,	/* 9730 */
7010334Shelge 	32,	16,	32*16,	1024,	hpam_off,	/* AMPEX capricorn */
7110334Shelge 	1,	1,	1,	1,	0,		/* rm02 - not used */
7210334Shelge };
7310334Shelge struct dkbad hpbad[MAXNMBA*8];
7410334Shelge int sectsiz;
7510334Shelge 
7610334Shelge hpopen(io)
7710334Shelge 	register struct iob *io;
7810334Shelge {
7910334Shelge 	register unit = io->i_unit;
8010334Shelge 	struct hpdevice *hpaddr = (struct hpdevice *)mbadrv(unit);
8110353Shelge 	register struct st *st;
8210334Shelge 
8310334Shelge 	mbainit(UNITTOMBA(unit));
8410334Shelge 	if (hp_type[unit] == 0) {
8510334Shelge 		register type = hpaddr->hpdt & MBDT_TYPE;
8610334Shelge 		register int i;
8710334Shelge 		struct iob tio;
8810334Shelge 
8910334Shelge 		for (i = 0; hptypes[i]; i++)
9010334Shelge 			if (hptypes[i] == type)
9110334Shelge 				goto found;
9210334Shelge 		_stop("unknown drive type");
9310334Shelge found:
9410334Shelge 		switch (i) {
9510334Shelge 		case 0: case 1:	{	/* rm03 or rm05 */
9610334Shelge 			register hpsn = hpaddr->hpsn;
9710334Shelge 
9810334Shelge 			if ((hpsn & SIMB_LU) != unit)
9910334Shelge 				break;
10010334Shelge 			switch ((hpsn & SIMB_MB) &~ (SIMB_S6|SIRM03|SIRM05)) {
10110334Shelge 			case SI9775D:
10210334Shelge 				i = 8;	/* si9775 */
10310334Shelge 				break;
10410334Shelge 			case SI9730D:
10510334Shelge 				i = 9;	/* si9730 */
10610334Shelge 				break;
10710334Shelge 			case SI9766:
10810334Shelge 				i = 1;	/* rm05 */
10910334Shelge 				hpaddr->hpcs1 = HP_RECAL|HP_GO;
11010334Shelge 				DELAY(100000);
11110334Shelge 				break;
11210334Shelge 			case SI9762:
11310334Shelge 				i = 0;	/* rm03 */
11410334Shelge 				break;
11510334Shelge 			}
11610334Shelge 			break;
11710334Shelge 		}
11810334Shelge 
11910334Shelge 		case 11:		/* rm02 */
12010334Shelge 			hpaddr->hpcs1 = HP_NOP;
12110334Shelge 			hpaddr->hphr = HPHR_MAXTRAK;
12210334Shelge 			if (MASKREG(hpaddr->hphr) == 15)
12310334Shelge 				i = 10;		/* ampex capricorn */
12410334Shelge 			else
12510334Shelge 				i = 0;		/* rm03 */
12610334Shelge 			break;
12710334Shelge 
12810334Shelge 		case 6: case 7:		/* ml11a ml11b */
12910334Shelge 			i = 6;			/* ml11a */
13010334Shelge 			break;
13110334Shelge 		}
13210334Shelge 		hp_type[unit] = i;
13310334Shelge 		/*
13410334Shelge 		 * Read in the bad sector table:
13510334Shelge 		 *	copy the contents of the io structure
13610334Shelge 		 *	to tio for use during the bb pointer
13710334Shelge 		 *	read operation.
13810334Shelge 		 */
13910334Shelge 		st = &hpst[hp_type[unit]];
14010334Shelge 		tio = *io;
14110334Shelge 		tio.i_bn = st->nspc * st->ncyl - st->nsect;
14210334Shelge 		tio.i_ma = (char *)&hpbad[tio.i_unit];
14310334Shelge 		tio.i_cc = sizeof (hpbad);
14410334Shelge 		tio.i_flgs |= F_RDDATA;
14510334Shelge 		for (i = 0; i < 5; i++) {
14610334Shelge 			if (hpstrategy(&tio, READ) == sizeof (hpbad))
14710334Shelge 				break;
14810334Shelge 			tio.i_bn += 2;
14910334Shelge 		}
15010334Shelge 		if (i == 5) {
15110334Shelge 			printf("Unable to read bad sector table\n");
15210334Shelge 			for (i = 0; i < MAXBADDESC; i++) {
15310334Shelge 				hpbad[unit].bt_bad[i].bt_cyl = -1;
15410334Shelge 				hpbad[unit].bt_bad[i].bt_trksec = -1;
15510334Shelge 			}
15610334Shelge 		}
15710334Shelge 	}
15810334Shelge 	if (io->i_boff < 0 || io->i_boff > 7 ||
15910334Shelge 	    st->off[io->i_boff]== -1)
16010334Shelge 		_stop("hp bad minor");
16110334Shelge 	io->i_boff = st->off[io->i_boff] * st->nspc;
16210334Shelge }
16310334Shelge 
16410334Shelge hpstrategy(io, func)
16510334Shelge 	register struct iob *io;
16610334Shelge {
16710334Shelge 	register unit = io->i_unit;
16810334Shelge 	struct mba_regs *mba = mbamba(unit);
16910334Shelge 	daddr_t bn;
17010334Shelge 	struct hpdevice *hpaddr = (struct hpdevice *)mbadrv(unit);
17110353Shelge 	struct st *st = &hpst[hp_type[unit]];
17210334Shelge 	int cn, tn, sn, bytecnt, bytesleft;
17310334Shelge 	daddr_t startblock;
17410334Shelge 	char *membase;
17510334Shelge 	int er1, er2, hprecal;
17610334Shelge 
17710334Shelge 	sectsiz = SECTSIZ;
17810334Shelge 	if ((io->i_flgs & (F_HDR|F_HCHECK)) != 0)
17910334Shelge 		sectsiz += HDRSIZ;
18010334Shelge 	if ((hpaddr->hpds & HPDS_VV) == 0) {
18110334Shelge 		hpaddr->hpcs1 = HP_DCLR|HP_GO;
18210334Shelge 		hpaddr->hpcs1 = HP_PRESET|HP_GO;
18310334Shelge 		if (hp_type[unit] != 6)		/* any but ml11 */
18410334Shelge 			hpaddr->hpof = HPOF_FMT22;
18510334Shelge 	}
18610334Shelge 	io->i_errcnt = 0;
18710334Shelge 	bytecnt = io->i_cc;
18810334Shelge 	membase = io->i_ma;
18910334Shelge 	startblock = io->i_bn;
190*10608Ssam 	hprecal = 0;
19110334Shelge readmore:
19210334Shelge 	bn = io->i_bn;
19310334Shelge 	cn = bn/st->nspc;
19410334Shelge 	sn = bn%st->nspc;
19510334Shelge 	tn = sn/st->nsect;
19610334Shelge 	sn = sn%st->nsect;
19710334Shelge 
19810334Shelge 	while ((hpaddr->hpds & HPDS_DRY) == 0)
19910334Shelge 		;
20010334Shelge 	if (hp_type[unit] == 6)		/* ml11 */
20110334Shelge 		hpaddr->hpda = bn;
20210334Shelge 	else {
20310334Shelge 		hpaddr->hpdc = cn;
20410334Shelge 		hpaddr->hpda = (tn << 8) + sn;
20510334Shelge 	}
20610334Shelge 	if (mbastart(io, func) != 0)		/* start transfer */
20710334Shelge 		return (-1);
20810334Shelge 
20910334Shelge 	while ((hpaddr->hpds & HPDS_DRY) == 0)
21010334Shelge 		;
21110334Shelge 	if (((hpaddr->hpds&HPDS_ERR) | (mba->mba_sr&MBSR_EBITS)) == 0 )
21210334Shelge 		return(bytecnt);
21310334Shelge 
21410334Shelge 	/* ------- error handling ------- */
21510334Shelge 
21610334Shelge 	if (bytesleft = MASKREG(mba->mba_bcr>>16))
21710334Shelge 		bytesleft |= 0xffff0000;	/* sign ext */
21810334Shelge 	bn = io->i_bn + (io->i_cc + bytesleft)/sectsiz;
21910334Shelge 	cn = bn/st->nspc;
22010334Shelge 	sn = bn%st->nspc;
22110334Shelge 	tn = sn/st->nsect;
22210334Shelge 	sn = sn%st->nsect;
22310334Shelge 	er1 = MASKREG(hpaddr->hper1);
22410334Shelge 	er2 = MASKREG(hpaddr->hper2);
22510334Shelge #ifdef HPDEBUG
22610334Shelge 	printf("hp error: (cyl,trk,sec)=(%d,%d,%d) ds=%b \n",
22710334Shelge 		cn, tn, sn, MASKREG(hpaddr->hpds), HPDS_BITS);
22810334Shelge 	printf("er1=%b er2=%b",
22910334Shelge 		er1, HPER1_BITS,
23010334Shelge 		er2, HPER2_BITS);
23110334Shelge 	printf("\n");
23210334Shelge #endif
23310334Shelge 	if (er1 & HPER1_HCRC) {
23410334Shelge 		er1 &= ~(HPER1_HCE|HPER1_FER);
23510334Shelge 		er2 &= ~HPER2_BSE;
23610334Shelge 	}
23710334Shelge 	if (er1&HPER1_WLE) {
23810334Shelge 		printf("hp%d: write locked\n", unit);
23910334Shelge 		return(-1);
24010334Shelge 	} else if ((er1&0xffff) == HPER1_FER && RP06) {
24110334Shelge 		goto badsect;
24210334Shelge 
24310334Shelge 	} else if (++io->i_errcnt > 27 ||
24410334Shelge 		   er1 & HPER1_HARD ||
24510334Shelge 		   (!ML11 && (er2 & HPER2_HARD))) {
246*10608Ssam hard0:
24710334Shelge 		io->i_error = EHER;
24810334Shelge 		if ((mba->mba_sr & (MBSR_WCKUP | MBSR_WCKLWR)) != 0)
24910334Shelge 			io->i_error = EWCK;
25010334Shelge hard:
25110334Shelge 		io->i_errblk = bn;
25210334Shelge 		printf("hp error: (cyl,trk,sec)=(%d,%d,%d) ds=%b \n",
25310334Shelge 			   cn, tn, sn, MASKREG(hpaddr->hpds), HPDS_BITS);
25410334Shelge 		printf("er1=%b er2=%b",
25510334Shelge 			   er1, HPER1_BITS,
25610334Shelge 			   er2, HPER2_BITS);
25710334Shelge 		if (hpaddr->hpmr)
25810334Shelge 			printf(" mr=%o", hpaddr->hpmr&0xffff);
25910334Shelge 		if (hpaddr->hpmr2)
26010334Shelge 			printf(" mr2=%o", hpaddr->hpmr2&0xffff);
26110334Shelge 		printf("\n");
26210334Shelge 		return(-1);
26310334Shelge 
26410334Shelge 	} else if ((er2 & HPER2_BSE) && !ML11) {
26510334Shelge badsect:
26610334Shelge 		if ((io->i_flgs & F_NBSF) != 0) {
26710334Shelge 			io->i_error = EBSE;
26810334Shelge 			goto hard;
26910334Shelge 		}
27010334Shelge 		if (hpecc(io, BSE) == 0)
27110334Shelge 			goto success;
27210334Shelge 		else {
27310334Shelge 			io->i_error = EBSE;
27410334Shelge 			goto hard;
27510334Shelge 		}
27610334Shelge 	} else if (RM80 && er2&HPER2_SSE) {
27710334Shelge 	/* skip sector error */
27810334Shelge 		(void) hpecc(io, SSE);
27910413Shelge 		startblock++;		/* since one sector was skipped */
28010334Shelge 		goto success;
28110334Shelge 	} else if ((er1&(HPER1_DCK|HPER1_ECH))==HPER1_DCK) {
28210334Shelge 		if ( hpecc(io, ECC) == 0)
28310334Shelge 			goto success;
28410334Shelge 		else {
28510334Shelge 			io->i_error = EECC;
28610334Shelge 			return(1);
28710334Shelge 		}
288*10608Ssam 	}
28910334Shelge 
290*10608Ssam 	if (ML11 && (io->i_errcnt >= 16))
291*10608Ssam 			goto hard0;
292*10608Ssam 
293*10608Ssam 	/* fall thru to retry */
294*10608Ssam 
29510334Shelge 	hpaddr->hpcs1 = HP_DCLR|HP_GO;
29610334Shelge 	while ((hpaddr->hpds & HPDS_DRY) == 0)
29710334Shelge 		;
298*10608Ssam 	if (((io->i_errcnt&07) == 4) ) {
29910334Shelge 		hpaddr->hpcs1 = HP_RECAL|HP_GO;
300*10608Ssam 		hprecal = 1;
301*10608Ssam 		goto try_again;
30210334Shelge 	}
30310334Shelge 	switch (hprecal) {
30410334Shelge 
30510334Shelge 	case 1:
30610334Shelge 		hpaddr->hpdc = cn;
30710334Shelge 		hpaddr->hpcs1 = HP_SEEK|HP_GO;
308*10608Ssam 		hprecal++;
309*10608Ssam 		goto try_again;
31010334Shelge 	case 2:
311*10608Ssam 		if (io->i_errcnt < 16 || (io->i_flgs & F_READ) == 0)
31210334Shelge 			goto donerecal;
31310334Shelge 		hpaddr->hpof = hp_offset[io->i_errcnt & 017]|HPOF_FMT22;
31410334Shelge 		hpaddr->hpcs1 = HP_OFFSET|HP_GO;
31510334Shelge 		hprecal++;
31610334Shelge 		goto try_again;
31710334Shelge 	donerecal:
31810334Shelge 	case 3:
31910334Shelge 		hprecal = 0;
32010334Shelge 		goto try_again;
32110334Shelge 	}
322*10608Ssam 	if (io->i_errcnt >= 16) {
323*10608Ssam 		hpaddr->hpcs1 = HP_RTC|HP_GO;
324*10608Ssam 		while (hpaddr->hpds & HPDS_PIP)
325*10608Ssam 			;
32610334Shelge 	}
327*10608Ssam 	goto try_again;
32810334Shelge success:		 /* continue with the next block */
32910334Shelge 	bn++;
33010334Shelge 	if ((bn-startblock) * sectsiz < bytecnt) {
33110334Shelge 
33210334Shelge try_again:		/* re-read same block */
33310334Shelge 		io->i_bn = bn;
33410334Shelge 		mba->mba_sr = -1;
33510334Shelge 		io->i_ma = membase + (io->i_bn - startblock)*sectsiz;
33610334Shelge 		io->i_cc = bytecnt - (io->i_bn - startblock)*sectsiz;
33710334Shelge #ifdef HPDEBUG
338*10608Ssam 		printf("restart: bl %d, byte %d, mem 0x%x hprecal %d\n",
339*10608Ssam 			io->i_bn, io->i_cc, io->i_ma, hprecal);
34010334Shelge #endif
34110334Shelge 		goto readmore;
34210334Shelge 	}
34310334Shelge 	return (bytecnt);
34410334Shelge }
34510334Shelge hpecc(io, flag)
34610334Shelge 	register struct iob *io;
34710334Shelge 	int flag;
34810334Shelge {
34910334Shelge 	register unit = io->i_unit;
35010334Shelge 	register struct mba_regs *mbp = mbamba(unit);
35110334Shelge 	register struct hpdevice *rp = (struct hpdevice *)mbadrv(unit);
35210353Shelge 	register struct st *st = &hpst[hp_type[unit]];
35310334Shelge 	int npf;
35410334Shelge 	int bn, cn, tn, sn;
35510334Shelge 	int bcr, tad;
35610334Shelge 
35710334Shelge 	if (bcr = MASKREG(mbp->mba_bcr>>16))
35810334Shelge 		bcr |= 0xffff0000;		/* sxt */
35910334Shelge 	npf = (bcr + io->i_cc)/sectsiz;		/* number of sectors read */
36010413Shelge 	bn = io->i_bn + npf;
36110334Shelge 	switch (flag) {
36210334Shelge 	case ECC:
36310334Shelge 		{
36410334Shelge 		register int i;
36510334Shelge 		caddr_t addr;
36610334Shelge 		int bit, byte, mask, ecccnt = 0;
36710334Shelge 
36810413Shelge 		printf("hp%d: soft ecc sn%d\n", unit, bn);
36910334Shelge 		mask = MASKREG(rp->hpec2);
37010334Shelge 		i = MASKREG(rp->hpec1) - 1;		/* -1 makes 0 origin */
37110334Shelge 		bit = i&07;
37210334Shelge 		i = (i&~07)>>3;
37310334Shelge 		byte = i;
37410334Shelge 		rp->hpcs1 = HP_DCLR | HP_GO;
37510334Shelge 		while (i <sectsiz && npf*sectsiz + i < io->i_cc && bit > -11) {
37610334Shelge 			addr = io->i_ma + (npf*sectsiz) + byte;
37710334Shelge #ifdef HPECCDEBUG
37810334Shelge 			printf("addr %x old:%x ",addr, (*addr&0xff));
37910334Shelge #endif
38010334Shelge 			if ((io->i_flgs & (F_CHECK|F_HCHECK)) == 0)
38110334Shelge 				*addr ^= (mask << bit);	/* don't 'correct' mem-
38210334Shelge 							 * ory during Wcheck */
38310334Shelge #ifdef HPECCDEBUG
38410334Shelge 			printf("new:%x\n",(*addr&0xff));
38510334Shelge #endif
38610334Shelge 			byte++;
38710334Shelge 			i++;
38810334Shelge 			bit -= 8;
38910334Shelge 			if ((ecccnt++>=MAXECC) && ((io->i_flgs&F_ECCLM) != 0))
39010334Shelge 				return(1);
39110334Shelge 		}
39210334Shelge 		return(0);
39310334Shelge 		}
39410334Shelge 
39510413Shelge 	case SSE:	/* skip sector error */
39610413Shelge 			/* set skip-sector-inhibit and read next sector */
39710334Shelge 		rp->hpcs1 = HP_DCLR | HP_GO;
39810413Shelge 		while(rp->hpds & HPDS_DRY == 0)
39910413Shelge 			;			/* avoid RMR error */
40010334Shelge 		rp->hpof |= HPOF_SSEI;
40110334Shelge 		return(0);
40210334Shelge 
40310334Shelge #ifndef NOBADSECT
40410334Shelge 	case BSE:
40510334Shelge #ifdef HPDEBUG
40610334Shelge 		printf("hpecc: BSE @ bn %d\n", bn);
40710334Shelge #endif
40810334Shelge 		rp->hpcs1 = HP_DCLR | HP_GO;
40910413Shelge 		bcr += sectsiz;
41010334Shelge 		tad = rp->hpda;
41110413Shelge 		if ((bn = isbad(&hpbad[unit], bn/st->nspc,tad>>8,tad&0x7f)) < 0)
41210334Shelge 			return(1);
41310334Shelge 		bn = st->ncyl*st->nspc - st->nsect - 1 - bn;
41410334Shelge 		cn = bn/st->nspc;
41510334Shelge 		sn = bn%st->nspc;
41610334Shelge 		tn = sn/st->nsect;
41710334Shelge 		sn %= st->nsect;
41810413Shelge 		io->i_cc = -sectsiz;
41910413Shelge 		io->i_ma += ((io->i_bn + npf -1)*sectsiz);
42010334Shelge #ifdef HPDEBUG
42110334Shelge 		printf("revector to cn %d tn %d sn %d\n", cn, tn, sn);
42210334Shelge #endif
42310334Shelge 		rp->hpdc = cn;
42410334Shelge 		rp->hpda = (tn<<8) + sn;
42510334Shelge 		mbp->mba_sr = -1;
42610334Shelge 		mbastart(io,io->i_flgs);
42710334Shelge 		io->i_errcnt = 0;	/* error has been corrected */
42810334Shelge 		if (rp->hpds&HPDS_ERR)
42910334Shelge 			return(1);
43010334Shelge 		else
43110334Shelge 			return(0);
43210334Shelge 	}
43310334Shelge }
43410334Shelge /*ARGSUSED*/
43510334Shelge hpioctl(io, cmd, arg)
43610334Shelge 	struct iob *io;
43710334Shelge 	int cmd;
43810334Shelge 	caddr_t arg;
43910334Shelge {
44010334Shelge 
44110353Shelge 	struct st *st = &hpst[hp_type[io->i_unit]], *tmp;
44210334Shelge 	struct mba_drv *drv = mbadrv(io->i_unit);
44310334Shelge 
44410334Shelge 	switch(cmd) {
44510334Shelge 
44610334Shelge 	case SAIODEVDATA:
44710334Shelge 		if ((drv->mbd_dt&MBDT_TAP) == 0) {
44810353Shelge 			tmp = (struct st *)arg;
44910353Shelge 			*tmp = *st;
45010334Shelge 			return(0);
45110334Shelge 		}
45210334Shelge 		else
45310334Shelge 			return(ECMD);
45410334Shelge 
45510334Shelge 	default:
45610334Shelge 		return (ECMD);
45710334Shelge 	}
45810334Shelge }
45910334Shelge 
460