Home | History | Annotate | Line # | Download | only in dev
sbc.c revision 1.24
      1 /*	$NetBSD: sbc.c,v 1.24 1997/04/18 17:38:08 scottr Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 1996 Scott Reynolds.  All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. All advertising materials mentioning features or use of this software
     15  *    must display the following acknowledgement:
     16  *      This product includes software developed by Scott Reynolds for
     17  *      the NetBSD Project.
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * This file contains only the machine-dependent parts of the mac68k
     35  * NCR 5380 SCSI driver.  (Autoconfig stuff and PDMA functions.)
     36  * The machine-independent parts are in ncr5380sbc.c
     37  *
     38  * Supported hardware includes:
     39  * Macintosh II family 5380-based controller
     40  *
     41  * Credits, history:
     42  *
     43  * Scott Reynolds wrote this module, based on work by Allen Briggs
     44  * (mac68k), Gordon W. Ross and David Jones (sun3), and Leo Weppelman
     45  * (atari).  Thanks to Allen for supplying crucial interpretation of the
     46  * NetBSD/mac68k 1.1 'ncrscsi' driver.  Also, Allen, Gordon, and Jason
     47  * Thorpe all helped to refine this code, and were considerable sources
     48  * of moral support.
     49  */
     50 
     51 #include <sys/types.h>
     52 #include <sys/param.h>
     53 #include <sys/systm.h>
     54 #include <sys/kernel.h>
     55 #include <sys/errno.h>
     56 #include <sys/device.h>
     57 #include <sys/buf.h>
     58 #include <sys/proc.h>
     59 #include <sys/user.h>
     60 
     61 #include <scsi/scsi_all.h>
     62 #include <scsi/scsi_debug.h>
     63 #include <scsi/scsiconf.h>
     64 
     65 #include <dev/ic/ncr5380reg.h>
     66 #include <dev/ic/ncr5380var.h>
     67 
     68 #include <machine/cpu.h>
     69 #include <machine/viareg.h>
     70 
     71 #include "sbcreg.h"
     72 #include "sbcvar.h"
     73 
     74 int	sbc_debug = 0 /* | SBC_DB_INTR | SBC_DB_DMA */;
     75 int	sbc_link_flags = 0 /* | SDEV_DB2 */;
     76 int	sbc_options = 0 /* | SBC_PDMA */;
     77 
     78 static	void	sbc_minphys __P((struct buf *bp));
     79 
     80 struct scsi_adapter	sbc_ops = {
     81 	ncr5380_scsi_cmd,		/* scsi_cmd()		*/
     82 	sbc_minphys,			/* scsi_minphys()	*/
     83 	NULL,				/* open_target_lu()	*/
     84 	NULL,				/* close_target_lu()	*/
     85 };
     86 
     87 /* This is copied from julian's bt driver */
     88 /* "so we have a default dev struct for our link struct." */
     89 struct scsi_device sbc_dev = {
     90 	NULL,		/* Use default error handler.	    */
     91 	NULL,		/* Use default start handler.		*/
     92 	NULL,		/* Use default async handler.	    */
     93 	NULL,		/* Use default "done" routine.	    */
     94 };
     95 
     96 struct cfdriver sbc_cd = {
     97 	NULL, "sbc", DV_DULL
     98 };
     99 
    100 static	int	sbc_ready __P((struct ncr5380_softc *));
    101 static	void	sbc_wait_not_req __P((struct ncr5380_softc *));
    102 
    103 static void
    104 sbc_minphys(struct buf *bp)
    105 {
    106 	if (bp->b_bcount > MAX_DMA_LEN)
    107 		bp->b_bcount = MAX_DMA_LEN;
    108 	return (minphys(bp));
    109 }
    110 
    111 
    112 /***
    113  * General support for Mac-specific SCSI logic.
    114  ***/
    115 
    116 void
    117 sbc_irq_intr(p)
    118 	void *p;
    119 {
    120 	struct ncr5380_softc *ncr_sc = p;
    121 	int claimed = 0;
    122 
    123 	/* How we ever arrive here without IRQ set is a mystery... */
    124 	if (*ncr_sc->sci_csr & SCI_CSR_INT) {
    125 #ifdef SBC_DEBUG
    126 		if (sbc_debug & SBC_DB_INTR)
    127 			decode_5380_intr(ncr_sc);
    128 #endif
    129 		claimed = ncr5380_intr(ncr_sc);
    130 		if (!claimed) {
    131 			if (((*ncr_sc->sci_csr & ~SCI_CSR_PHASE_MATCH) == SCI_CSR_INT)
    132 			    && ((*ncr_sc->sci_bus_csr & ~SCI_BUS_RST) == 0))
    133 				SCI_CLR_INTR(ncr_sc);	/* RST interrupt */
    134 #ifdef SBC_DEBUG
    135 			else {
    136 				printf("%s: spurious intr\n",
    137 				    ncr_sc->sc_dev.dv_xname);
    138 				SBC_BREAK;
    139 			}
    140 #endif
    141 		}
    142 	}
    143 }
    144 
    145 #ifdef SBC_DEBUG
    146 void
    147 decode_5380_intr(ncr_sc)
    148 	struct ncr5380_softc *ncr_sc;
    149 {
    150 	u_char csr = *ncr_sc->sci_csr;
    151 	u_char bus_csr = *ncr_sc->sci_bus_csr;
    152 
    153 	if (((csr & ~(SCI_CSR_PHASE_MATCH | SCI_CSR_ATN)) == SCI_CSR_INT) &&
    154 	    ((bus_csr & ~(SCI_BUS_MSG | SCI_BUS_CD | SCI_BUS_IO | SCI_BUS_DBP)) == SCI_BUS_SEL)) {
    155 		if (csr & SCI_BUS_IO)
    156 			printf("%s: reselect\n", ncr_sc->sc_dev.dv_xname);
    157 		else
    158 			printf("%s: select\n", ncr_sc->sc_dev.dv_xname);
    159 	} else if (((csr & ~SCI_CSR_ACK) == (SCI_CSR_DONE | SCI_CSR_INT)) &&
    160 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_SEL)) == SCI_BUS_BSY))
    161 		printf("%s: dma eop\n", ncr_sc->sc_dev.dv_xname);
    162 	else if (((csr & ~SCI_CSR_PHASE_MATCH) == SCI_CSR_INT) &&
    163 	    ((bus_csr & ~SCI_BUS_RST) == 0))
    164 		printf("%s: bus reset\n", ncr_sc->sc_dev.dv_xname);
    165 	else if (((csr & ~(SCI_CSR_DREQ | SCI_CSR_ATN | SCI_CSR_ACK)) == (SCI_CSR_PERR | SCI_CSR_INT | SCI_CSR_PHASE_MATCH)) &&
    166 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_SEL)) == SCI_BUS_BSY))
    167 		printf("%s: parity error\n", ncr_sc->sc_dev.dv_xname);
    168 	else if (((csr & ~SCI_CSR_ATN) == SCI_CSR_INT) &&
    169 	    ((bus_csr & (SCI_BUS_RST | SCI_BUS_BSY | SCI_BUS_REQ | SCI_BUS_SEL)) == (SCI_BUS_BSY | SCI_BUS_REQ)))
    170 		printf("%s: phase mismatch\n", ncr_sc->sc_dev.dv_xname);
    171 	else if (((csr & ~SCI_CSR_PHASE_MATCH) == (SCI_CSR_INT | SCI_CSR_DISC)) &&
    172 	    (bus_csr == 0))
    173 		printf("%s: disconnect\n", ncr_sc->sc_dev.dv_xname);
    174 	else
    175 		printf("%s: unknown intr: csr=%x, bus_csr=%x\n",
    176 		    ncr_sc->sc_dev.dv_xname, csr, bus_csr);
    177 }
    178 #endif
    179 
    180 
    181 /***
    182  * The following code implements polled PDMA.
    183  ***/
    184 
    185 #define	TIMEOUT	5000000			/* x 2 usec = 10 sec */
    186 
    187 static __inline__ int
    188 sbc_ready(sc)
    189 	struct ncr5380_softc *sc;
    190 {
    191 	int i = TIMEOUT;
    192 
    193 	for (;;) {
    194 		if ((*sc->sci_csr & (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH)) ==
    195 		    (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH))
    196 			return 1;
    197 		if (((*sc->sci_csr & SCI_CSR_PHASE_MATCH) == 0) ||
    198 		    (SCI_BUSY(sc) == 0))
    199 			return 0;
    200 		if (--i < 0)
    201 			break;
    202 		delay(2);
    203 	}
    204 
    205 	printf("%s: ready timeout\n", sc->sc_dev.dv_xname);
    206 	return 0;
    207 }
    208 
    209 static __inline__ void
    210 sbc_wait_not_req(sc)
    211 	struct ncr5380_softc *sc;
    212 {
    213 	int i = TIMEOUT;
    214 
    215 	for (;;) {
    216 		if ((*sc->sci_bus_csr & SCI_BUS_REQ) == 0 ||
    217 		    (*sc->sci_csr & SCI_CSR_PHASE_MATCH) == 0 ||
    218 		    SCI_BUSY(sc) == 0) {
    219 			return;
    220 		}
    221 		if (--i < 0)
    222 			break;
    223 		delay(2);
    224 	}
    225 	printf("%s: pdma not_req timeout\n", sc->sc_dev.dv_xname);
    226 }
    227 
    228 int
    229 sbc_pdma_in(ncr_sc, phase, datalen, data)
    230 	struct ncr5380_softc *ncr_sc;
    231 	int phase, datalen;
    232 	u_char *data;
    233 {
    234 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
    235 	volatile u_int32_t *long_data = (u_int32_t *)sc->sc_drq_addr;
    236 	volatile u_int8_t *byte_data = (u_int8_t *)sc->sc_nodrq_addr;
    237 	int resid, s;
    238 
    239 	s = splbio();
    240 	*ncr_sc->sci_mode |= SCI_MODE_DMA;
    241 	*ncr_sc->sci_irecv = 0;
    242 
    243 #define R4	*((u_int32_t *)data)++ = *long_data++
    244 #define R1	*data++ = *byte_data++
    245 	for (resid = datalen; resid >= 128; resid -= 128) {
    246 		if (sbc_ready(ncr_sc) == 0)
    247 			goto interrupt;
    248 		R4; R4; R4; R4; R4; R4; R4; R4;
    249 		R4; R4; R4; R4; R4; R4; R4; R4;
    250 		R4; R4; R4; R4; R4; R4; R4; R4;
    251 		R4; R4; R4; R4; R4; R4; R4; R4;
    252 
    253 		long_data = (u_int32_t *)sc->sc_drq_addr;
    254 		byte_data = (u_int8_t *)sc->sc_nodrq_addr;
    255 	}
    256 	while (resid) {
    257 		if (sbc_ready(ncr_sc) == 0)
    258 			goto interrupt;
    259 		R1;
    260 		resid--;
    261 	}
    262 #undef R4
    263 #undef R1
    264 
    265 	sbc_wait_not_req(ncr_sc);
    266 interrupt:
    267 	SCI_CLR_INTR(ncr_sc);
    268 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
    269 	splx(s);
    270 	return datalen - resid;
    271 }
    272 
    273 int
    274 sbc_pdma_out(ncr_sc, phase, datalen, data)
    275 	struct ncr5380_softc *ncr_sc;
    276 	int phase, datalen;
    277 	u_char *data;
    278 {
    279 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
    280 	volatile u_int32_t *long_data = (u_int32_t *)sc->sc_drq_addr;
    281 	volatile u_int8_t *byte_data = (u_int8_t *)sc->sc_nodrq_addr;
    282 	int i, s, resid;
    283 	u_char icmd;
    284 
    285 	if (datalen < 64)
    286 		return ncr5380_pio_out(ncr_sc, phase, datalen, data);
    287 
    288 	s = splbio();
    289 	icmd = *(ncr_sc->sci_icmd) & SCI_ICMD_RMASK;
    290 	*ncr_sc->sci_icmd = icmd | SCI_ICMD_DATA;
    291 	*ncr_sc->sci_mode |= SCI_MODE_DMA;
    292 	*ncr_sc->sci_dma_send = 0;
    293 
    294 	resid = datalen;
    295 	if (sbc_ready(ncr_sc) == 0)
    296 		goto interrupt;
    297 
    298 #define W1	*byte_data++ = *data++
    299 #define W4	*long_data++ = *((u_int32_t *)data)++
    300 	while (resid >= 64) {
    301 		if (sbc_ready(ncr_sc) == 0)
    302 			goto interrupt;
    303 		W1;
    304 		resid--;
    305 		if (sbc_ready(ncr_sc) == 0)
    306 			goto interrupt;
    307 		W1;
    308 		resid--;
    309 		if (sbc_ready(ncr_sc) == 0)
    310 			goto interrupt;
    311 		W1;
    312 		resid--;
    313 		if (sbc_ready(ncr_sc) == 0)
    314 			goto interrupt;
    315 		W1;
    316 		resid--;
    317 		if (sbc_ready(ncr_sc) == 0)
    318 			goto interrupt;
    319 		W4; W4; W4; W4;
    320 		W4; W4; W4; W4;
    321 		W4; W4; W4; W4;
    322 		W4; W4; W4;
    323 		resid -= 60;
    324 
    325 		long_data = (u_int32_t *)sc->sc_drq_addr;
    326 		byte_data = (u_int8_t *)sc->sc_nodrq_addr;
    327 	}
    328 	for (; resid; resid--) {
    329 		if (sbc_ready(ncr_sc) == 0)
    330 			goto interrupt;
    331 		W1;
    332 	}
    333 #undef  W1
    334 #undef  W4
    335 
    336 	for (i = TIMEOUT; i > 0; i--) {
    337 		if ((*ncr_sc->sci_csr & (SCI_CSR_DREQ|SCI_CSR_PHASE_MATCH))
    338 		    != SCI_CSR_DREQ)
    339 			break;
    340 	}
    341 	if (i != 0)
    342 		*byte_data = 0;
    343 	else
    344 		printf("%s: timeout waiting for final SCI_DSR_DREQ.\n",
    345 			ncr_sc->sc_dev.dv_xname);
    346 
    347 	sbc_wait_not_req(ncr_sc);
    348 interrupt:
    349 	SCI_CLR_INTR(ncr_sc);
    350 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
    351 	*ncr_sc->sci_icmd = icmd;
    352 	splx(s);
    353 	return (datalen - resid);
    354 }
    355 
    356 
    357 /***
    358  * The following code implements interrupt-driven PDMA.
    359  ***/
    360 
    361 /*
    362  * This is the meat of the PDMA transfer.
    363  * When we get here, we shove data as fast as the mac can take it.
    364  * We depend on several things:
    365  *   * All macs after the Mac Plus that have a 5380 chip should have a general
    366  *     logic IC that handshakes data for blind transfers.
    367  *   * If the SCSI controller finishes sending/receiving data before we do,
    368  *     the same general logic IC will generate a /BERR for us in short order.
    369  *   * The fault address for said /BERR minus the base address for the
    370  *     transfer will be the amount of data that was actually written.
    371  *
    372  * We use the nofault flag and the setjmp/longjmp in locore.s so we can
    373  * detect and handle the bus error for early termination of a command.
    374  * This is usually caused by a disconnecting target.
    375  */
    376 void
    377 sbc_drq_intr(p)
    378 	void *p;
    379 {
    380 	extern int *nofault, mac68k_buserr_addr;
    381 	struct sbc_softc *sc = (struct sbc_softc *)p;
    382 	struct ncr5380_softc *ncr_sc = (struct ncr5380_softc *)p;
    383 	struct sci_req *sr = ncr_sc->sc_current;
    384 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
    385 	label_t faultbuf;
    386 	volatile u_int32_t *long_drq;
    387 	u_int32_t *long_data;
    388 	volatile u_int8_t *drq;
    389 	u_int8_t *data;
    390 	int count, dcount, resid;
    391 #ifdef SBC_WRITE_HACK
    392 	u_int8_t tmp;
    393 #endif
    394 
    395 	/*
    396 	 * If we're not ready to xfer data, or have no more, just return.
    397 	 */
    398 	if ((*ncr_sc->sci_csr & SCI_CSR_DREQ) == 0 || dh->dh_len == 0)
    399 		return;
    400 
    401 #ifdef SBC_DEBUG
    402 	if (sbc_debug & SBC_DB_INTR)
    403 		printf("%s: drq intr, dh_len=0x%x, dh_flags=0x%x\n",
    404 		    ncr_sc->sc_dev.dv_xname, dh->dh_len, dh->dh_flags);
    405 #endif
    406 
    407 	/*
    408 	 * Setup for a possible bus error caused by SCSI controller
    409 	 * switching out of DATA-IN/OUT before we're done with the
    410 	 * current transfer.
    411 	 */
    412 	nofault = (int *) &faultbuf;
    413 
    414 	if (setjmp((label_t *)nofault)) {
    415 		nofault = (int *) 0;
    416 		if ((dh->dh_flags & SBC_DH_DONE) == 0) {
    417 			count = ((  (u_long)mac68k_buserr_addr
    418 				  - (u_long)sc->sc_drq_addr));
    419 
    420 			if ((count < 0) || (count > dh->dh_len)) {
    421 				printf("%s: complete=0x%x (pending 0x%x)\n",
    422 				    ncr_sc->sc_dev.dv_xname, count, dh->dh_len);
    423 				panic("something is wrong");
    424 			}
    425 
    426 			dh->dh_addr += count;
    427 			dh->dh_len -= count;
    428 		} else
    429 			count = 0;
    430 
    431 #ifdef SBC_DEBUG
    432 		if (sbc_debug & SBC_DB_INTR)
    433 			printf("%s: drq /berr, complete=0x%x (pending 0x%x)\n",
    434 			   ncr_sc->sc_dev.dv_xname, count, dh->dh_len);
    435 #endif
    436 		mac68k_buserr_addr = 0;
    437 
    438 		return;
    439 	}
    440 
    441 	if (dh->dh_flags & SBC_DH_OUT) { /* Data Out */
    442 #if notyet /* XXX */
    443 		/*
    444 		 * Get the source address aligned.
    445 		 */
    446 		resid =
    447 		    count = min(dh->dh_len, 4 - (((int)dh->dh_addr) & 0x3));
    448 		if (count && count < 4) {
    449 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
    450 			data = (u_int8_t *)dh->dh_addr;
    451 
    452 #define W1		*drq++ = *data++
    453 			while (count) {
    454 				W1; count--;
    455 			}
    456 #undef W1
    457 			dh->dh_addr += resid;
    458 			dh->dh_len -= resid;
    459 		}
    460 
    461 		/*
    462 		 * Start the transfer.
    463 		 */
    464 		while (dh->dh_len) {
    465 			dcount = count = min(dh->dh_len, MAX_DMA_LEN);
    466 			long_drq = (volatile u_int32_t *)sc->sc_drq_addr;
    467 			long_data = (u_int32_t *)dh->dh_addr;
    468 
    469 #define W4		*long_drq++ = *long_data++
    470 			while (count >= 64) {
    471 				W4; W4; W4; W4; W4; W4; W4; W4;
    472 				W4; W4; W4; W4; W4; W4; W4; W4; /*  64 */
    473 				count -= 64;
    474 			}
    475 			while (count >= 4) {
    476 				W4; count -= 4;
    477 			}
    478 #undef W4
    479 			data = (u_int8_t *)long_data;
    480 			drq = (u_int8_t *)long_drq;
    481 #else /* notyet */
    482 		/*
    483 		 * Start the transfer.
    484 		 */
    485 		while (dh->dh_len) {
    486 			dcount = count = min(dh->dh_len, MAX_DMA_LEN);
    487 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
    488 			data = (u_int8_t *)dh->dh_addr;
    489 #endif /* notyet */
    490 
    491 #define W1		*drq++ = *data++
    492 			while (count) {
    493 				W1; count--;
    494 			}
    495 #undef W1
    496 			dh->dh_len -= dcount;
    497 			dh->dh_addr += dcount;
    498 		}
    499 		dh->dh_flags |= SBC_DH_DONE;
    500 
    501 #ifdef SBC_WRITE_HACK
    502 		/*
    503 		 * XXX -- Read a byte from the SBC to trigger a /BERR.
    504 		 * This seems to be necessary for us to notice that
    505 		 * the target has disconnected.  Ick.  06 jun 1996 (sr)
    506 		 */
    507 		if (dcount >= MAX_DMA_LEN) {
    508 #if 0
    509 			while ((*ncr_sc->sci_csr & SCI_CSR_ACK) == 0)
    510 				;
    511 #endif
    512 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
    513 		}
    514 		tmp = *drq;
    515 #endif
    516 	} else {	/* Data In */
    517 		/*
    518 		 * Get the dest address aligned.
    519 		 */
    520 		resid =
    521 		    count = min(dh->dh_len, 4 - (((int)dh->dh_addr) & 0x3));
    522 		if (count && count < 4) {
    523 			data = (u_int8_t *)dh->dh_addr;
    524 			drq = (volatile u_int8_t *)sc->sc_drq_addr;
    525 
    526 #define R1		*data++ = *drq++
    527 			while (count) {
    528 				R1; count--;
    529 			}
    530 #undef R1
    531 			dh->dh_addr += resid;
    532 			dh->dh_len -= resid;
    533 		}
    534 
    535 		/*
    536 		 * Start the transfer.
    537 		 */
    538 		while (dh->dh_len) {
    539 			dcount = count = min(dh->dh_len, MAX_DMA_LEN);
    540 			long_data = (u_int32_t *)dh->dh_addr;
    541 			long_drq = (volatile u_int32_t *)sc->sc_drq_addr;
    542 
    543 #define R4		*long_data++ = *long_drq++
    544 			while (count >= 64) {
    545 				R4; R4; R4; R4; R4; R4; R4; R4;
    546 				R4; R4; R4; R4; R4; R4; R4; R4;	/* 64 */
    547 				count -= 64;
    548 			}
    549 			while (count >= 4) {
    550 				R4; count -= 4;
    551 			}
    552 #undef R4
    553 			data = (u_int8_t *)long_data;
    554 			drq = (volatile u_int8_t *)long_drq;
    555 
    556 #define R1		*data++ = *drq++
    557 			while (count) {
    558 				R1; count--;
    559 			}
    560 #undef R1
    561 			dh->dh_len -= dcount;
    562 			dh->dh_addr += dcount;
    563 		}
    564 		dh->dh_flags |= SBC_DH_DONE;
    565 	}
    566 
    567 	/*
    568 	 * OK.  No bus error occurred above.  Clear the nofault flag
    569 	 * so we no longer short-circuit bus errors.
    570 	 */
    571 	nofault = (int *) 0;
    572 
    573 #ifdef SBC_DEBUG
    574 	if (sbc_debug & (SBC_DB_REG | SBC_DB_INTR))
    575 		printf("%s: drq intr complete: csr=0x%x, bus_csr=0x%x\n",
    576 		    ncr_sc->sc_dev.dv_xname, *ncr_sc->sci_csr,
    577 		    *ncr_sc->sci_bus_csr);
    578 #endif
    579 }
    580 
    581 void
    582 sbc_dma_alloc(ncr_sc)
    583 	struct ncr5380_softc *ncr_sc;
    584 {
    585 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
    586 	struct sci_req *sr = ncr_sc->sc_current;
    587 	struct scsi_xfer *xs = sr->sr_xs;
    588 	struct sbc_pdma_handle *dh;
    589 	int		i, xlen;
    590 
    591 #ifdef DIAGNOSTIC
    592 	if (sr->sr_dma_hand != NULL)
    593 		panic("sbc_dma_alloc: already have PDMA handle");
    594 #endif
    595 
    596 	/* Polled transfers shouldn't allocate a PDMA handle. */
    597 	if (sr->sr_flags & SR_IMMED)
    598 		return;
    599 
    600 	xlen = ncr_sc->sc_datalen;
    601 
    602 	/* Make sure our caller checked sc_min_dma_len. */
    603 	if (xlen < MIN_DMA_LEN)
    604 		panic("sbc_dma_alloc: len=0x%x\n", xlen);
    605 
    606 	/*
    607 	 * Find free PDMA handle.  Guaranteed to find one since we
    608 	 * have as many PDMA handles as the driver has processes.
    609 	 * (instances?)
    610 	 */
    611 	 for (i = 0; i < SCI_OPENINGS; i++) {
    612 		if ((sc->sc_pdma[i].dh_flags & SBC_DH_BUSY) == 0)
    613 			goto found;
    614 	}
    615 	panic("sbc: no free PDMA handles");
    616 found:
    617 	dh = &sc->sc_pdma[i];
    618 	dh->dh_flags = SBC_DH_BUSY;
    619 	dh->dh_addr = ncr_sc->sc_dataptr;
    620 	dh->dh_len = xlen;
    621 
    622 	/* Copy the 'write' flag for convenience. */
    623 	if (xs->flags & SCSI_DATA_OUT)
    624 		dh->dh_flags |= SBC_DH_OUT;
    625 
    626 	sr->sr_dma_hand = dh;
    627 }
    628 
    629 void
    630 sbc_dma_free(ncr_sc)
    631 	struct ncr5380_softc *ncr_sc;
    632 {
    633 	struct sci_req *sr = ncr_sc->sc_current;
    634 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
    635 
    636 #ifdef DIAGNOSTIC
    637 	if (sr->sr_dma_hand == NULL)
    638 		panic("sbc_dma_free: no DMA handle");
    639 #endif
    640 
    641 	if (ncr_sc->sc_state & NCR_DOINGDMA)
    642 		panic("sbc_dma_free: free while in progress");
    643 
    644 	if (dh->dh_flags & SBC_DH_BUSY) {
    645 		dh->dh_flags = 0;
    646 		dh->dh_addr = NULL;
    647 		dh->dh_len = 0;
    648 	}
    649 	sr->sr_dma_hand = NULL;
    650 }
    651 
    652 void
    653 sbc_dma_poll(ncr_sc)
    654 	struct ncr5380_softc *ncr_sc;
    655 {
    656 	struct sci_req *sr = ncr_sc->sc_current;
    657 
    658 	/*
    659 	 * We shouldn't arrive here; if SR_IMMED is set, then
    660 	 * dma_alloc() should have refused to allocate a handle
    661 	 * for the transfer.  This forces the polled PDMA code
    662 	 * to handle the request...
    663 	 */
    664 #ifdef SBC_DEBUG
    665 	if (sbc_debug & SBC_DB_DMA)
    666 		printf("%s: lost DRQ interrupt?\n", ncr_sc->sc_dev.dv_xname);
    667 #endif
    668 	sr->sr_flags |= SR_OVERDUE;
    669 }
    670 
    671 void
    672 sbc_dma_setup(ncr_sc)
    673 	struct ncr5380_softc *ncr_sc;
    674 {
    675 	/* Not needed; we don't have real DMA */
    676 }
    677 
    678 void
    679 sbc_dma_start(ncr_sc)
    680 	struct ncr5380_softc *ncr_sc;
    681 {
    682 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
    683 	struct sci_req *sr = ncr_sc->sc_current;
    684 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
    685 
    686 	/*
    687 	 * Match bus phase, clear pending interrupts, set DMA mode, and
    688 	 * assert data bus (for writing only), then start the transfer.
    689 	 */
    690 	if (dh->dh_flags & SBC_DH_OUT) {
    691 		*ncr_sc->sci_tcmd = PHASE_DATA_OUT;
    692 		SCI_CLR_INTR(ncr_sc);
    693 		if (sc->sc_clrintr)
    694 			(*sc->sc_clrintr)(ncr_sc);
    695 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
    696 		*ncr_sc->sci_icmd = SCI_ICMD_DATA;
    697 		*ncr_sc->sci_dma_send = 0;
    698 	} else {
    699 		*ncr_sc->sci_tcmd = PHASE_DATA_IN;
    700 		SCI_CLR_INTR(ncr_sc);
    701 		if (sc->sc_clrintr)
    702 			(*sc->sc_clrintr)(ncr_sc);
    703 		*ncr_sc->sci_mode |= SCI_MODE_DMA;
    704 		*ncr_sc->sci_icmd = 0;
    705 		*ncr_sc->sci_irecv = 0;
    706 	}
    707 	ncr_sc->sc_state |= NCR_DOINGDMA;
    708 
    709 #ifdef SBC_DEBUG
    710 	if (sbc_debug & SBC_DB_DMA)
    711 		printf("%s: PDMA started, va=%p, len=0x%x\n",
    712 		    ncr_sc->sc_dev.dv_xname, dh->dh_addr, dh->dh_len);
    713 #endif
    714 }
    715 
    716 void
    717 sbc_dma_eop(ncr_sc)
    718 	struct ncr5380_softc *ncr_sc;
    719 {
    720 	/* Not used; the EOP pin is wired high (GMFH, pp. 389-390) */
    721 }
    722 
    723 void
    724 sbc_dma_stop(ncr_sc)
    725 	struct ncr5380_softc *ncr_sc;
    726 {
    727 	struct sbc_softc *sc = (struct sbc_softc *)ncr_sc;
    728 	struct sci_req *sr = ncr_sc->sc_current;
    729 	struct sbc_pdma_handle *dh = sr->sr_dma_hand;
    730 	int ntrans;
    731 
    732 	if ((ncr_sc->sc_state & NCR_DOINGDMA) == 0) {
    733 #ifdef SBC_DEBUG
    734 		if (sbc_debug & SBC_DB_DMA)
    735 			printf("%s: dma_stop: DMA not running\n",
    736 			    ncr_sc->sc_dev.dv_xname);
    737 #endif
    738 		return;
    739 	}
    740 	ncr_sc->sc_state &= ~NCR_DOINGDMA;
    741 
    742 	if ((ncr_sc->sc_state & NCR_ABORTING) == 0) {
    743 		ntrans = ncr_sc->sc_datalen - dh->dh_len;
    744 
    745 #ifdef SBC_DEBUG
    746 		if (sbc_debug & SBC_DB_DMA)
    747 			printf("%s: dma_stop: ntrans=0x%x\n",
    748 			    ncr_sc->sc_dev.dv_xname, ntrans);
    749 #endif
    750 
    751 		if (ntrans > ncr_sc->sc_datalen)
    752 			panic("sbc_dma_stop: excess transfer\n");
    753 
    754 		/* Adjust data pointer */
    755 		ncr_sc->sc_dataptr += ntrans;
    756 		ncr_sc->sc_datalen -= ntrans;
    757 
    758 		/* Clear any pending interrupts. */
    759 		SCI_CLR_INTR(ncr_sc);
    760 		if (sc->sc_clrintr)
    761 			(*sc->sc_clrintr)(ncr_sc);
    762 	}
    763 
    764 	/* Put SBIC back into PIO mode. */
    765 	*ncr_sc->sci_mode &= ~SCI_MODE_DMA;
    766 	*ncr_sc->sci_icmd = 0;
    767 
    768 #ifdef SBC_DEBUG
    769 	if (sbc_debug & SBC_DB_REG)
    770 		printf("%s: dma_stop: csr=0x%x, bus_csr=0x%x\n",
    771 		    ncr_sc->sc_dev.dv_xname, *ncr_sc->sci_csr,
    772 		    *ncr_sc->sci_bus_csr);
    773 #endif
    774 }
    775