xref: /openbsd/sys/dev/pci/pcscp.c (revision 771fbea0)
1 /*	$OpenBSD: pcscp.c,v 1.20 2015/03/14 03:38:48 jsg Exp $	*/
2 /*	$NetBSD: pcscp.c,v 1.26 2003/10/19 10:25:42 tsutsui Exp $	*/
3 
4 /*-
5  * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
6  * All rights reserved.
7  *
8  * This code is derived from software contributed to The NetBSD Foundation
9  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
10  * NASA Ames Research Center; Izumi Tsutsui.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
23  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
25  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31  * POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 /*
35  * pcscp.c: device dependent code for AMD Am53c974 (PCscsi-PCI)
36  * written by Izumi Tsutsui <tsutsui@ceres.dti.ne.jp>
37  *
38  * Technical manual available at
39  * http://www.amd.com/files/connectivitysolutions/networking/archivednetworking/19113.pdf
40  */
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/device.h>
45 #include <sys/buf.h>
46 
47 #include <machine/bus.h>
48 
49 #include <scsi/scsi_all.h>
50 #include <scsi/scsiconf.h>
51 #include <scsi/scsi_message.h>
52 
53 #include <dev/pci/pcireg.h>
54 #include <dev/pci/pcivar.h>
55 #include <dev/pci/pcidevs.h>
56 
57 #include <dev/ic/ncr53c9xreg.h>
58 #include <dev/ic/ncr53c9xvar.h>
59 
60 #include <dev/pci/pcscpreg.h>
61 
62 #define IO_MAP_REG	0x10
63 
64 struct pcscp_softc {
65 	struct ncr53c9x_softc sc_ncr53c9x;	/* glue to MI code */
66 
67 	bus_space_tag_t sc_st;		/* bus space tag */
68 	bus_space_handle_t sc_sh;	/* bus space handle */
69 	void *sc_ih;			/* interrupt cookie */
70 
71 	bus_dma_tag_t sc_dmat;		/* DMA tag */
72 
73 	bus_dmamap_t sc_xfermap;	/* DMA map for transfers */
74 
75 	u_int32_t *sc_mdladdr;		/* MDL array */
76 	bus_dmamap_t sc_mdldmap;	/* MDL DMA map */
77 
78 	int	sc_active;		/* DMA state */
79 	int	sc_datain;		/* DMA Data Direction */
80 	size_t	sc_dmasize;		/* DMA size */
81 	char	**sc_dmaaddr;		/* DMA address */
82 	size_t	*sc_dmalen;		/* DMA length */
83 };
84 
85 #define	READ_DMAREG(sc, reg) \
86 	bus_space_read_4((sc)->sc_st, (sc)->sc_sh, (reg))
87 #define	WRITE_DMAREG(sc, reg, var) \
88 	bus_space_write_4((sc)->sc_st, (sc)->sc_sh, (reg), (var))
89 
90 #define	PCSCP_READ_REG(sc, reg) \
91 	bus_space_read_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2)
92 #define	PCSCP_WRITE_REG(sc, reg, val) \
93 	bus_space_write_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2, (val))
94 
95 int	pcscp_match(struct device *, void *, void *);
96 void	pcscp_attach(struct device *, struct device *, void *);
97 
98 struct cfattach pcscp_ca = {
99 	sizeof(struct pcscp_softc), pcscp_match, pcscp_attach
100 };
101 
102 struct cfdriver pcscp_cd = {
103 	NULL, "pcscp", DV_DULL
104 };
105 
106 /*
107  * Functions and the switch for the MI code.
108  */
109 
110 u_char	pcscp_read_reg(struct ncr53c9x_softc *, int);
111 void	pcscp_write_reg(struct ncr53c9x_softc *, int, u_char);
112 int	pcscp_dma_isintr(struct ncr53c9x_softc *);
113 void	pcscp_dma_reset(struct ncr53c9x_softc *);
114 int	pcscp_dma_intr(struct ncr53c9x_softc *);
115 int	pcscp_dma_setup(struct ncr53c9x_softc *, caddr_t *,
116 			       size_t *, int, size_t *);
117 void	pcscp_dma_go(struct ncr53c9x_softc *);
118 void	pcscp_dma_stop(struct ncr53c9x_softc *);
119 int	pcscp_dma_isactive(struct ncr53c9x_softc *);
120 
121 struct ncr53c9x_glue pcscp_glue = {
122 	pcscp_read_reg,
123 	pcscp_write_reg,
124 	pcscp_dma_isintr,
125 	pcscp_dma_reset,
126 	pcscp_dma_intr,
127 	pcscp_dma_setup,
128 	pcscp_dma_go,
129 	pcscp_dma_stop,
130 	pcscp_dma_isactive,
131 	NULL,			/* gl_clear_latched_intr */
132 };
133 
134 int
135 pcscp_match(struct device *parent, void *match, void *aux)
136 {
137 	struct pci_attach_args *pa = aux;
138 
139 	if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_AMD)
140 		return 0;
141 
142 	switch (PCI_PRODUCT(pa->pa_id)) {
143 	case PCI_PRODUCT_AMD_PCSCSI_PCI:
144 		return 1;
145 	}
146 	return 0;
147 }
148 
149 /*
150  * Attach this instance, and then all the sub-devices
151  */
152 void
153 pcscp_attach(struct device *parent, struct device *self, void *aux)
154 {
155 	struct pci_attach_args *pa = aux;
156 	struct pcscp_softc *esc = (void *)self;
157 	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
158 	bus_space_tag_t iot;
159 	bus_space_handle_t ioh;
160 	pci_intr_handle_t ih;
161 	const char *intrstr;
162 	bus_dma_segment_t seg;
163 	int error, rseg;
164 
165 	if (pci_mapreg_map(pa, IO_MAP_REG, PCI_MAPREG_TYPE_IO, 0,
166 	     &iot, &ioh, NULL, NULL, 0)) {
167 		printf("%s: unable to map registers\n", sc->sc_dev.dv_xname);
168 		return;
169 	}
170 
171 	sc->sc_glue = &pcscp_glue;
172 
173 	esc->sc_st = iot;
174 	esc->sc_sh = ioh;
175 	esc->sc_dmat = pa->pa_dmat;
176 
177 	/*
178 	 * XXX More of this should be in ncr53c9x_attach(), but
179 	 * XXX should we really poke around the chip that much in
180 	 * XXX the MI code?  Think about this more...
181 	 */
182 
183 	/*
184 	 * Set up static configuration info.
185 	 */
186 
187 	/*
188 	 * XXX should read configuration from EEPROM?
189 	 *
190 	 * MI ncr53c9x driver does not support configuration
191 	 * per each target device, though...
192 	 */
193 	sc->sc_id = 7;
194 	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
195 	sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_FE;
196 	sc->sc_cfg3 = NCRAMDCFG3_IDM | NCRAMDCFG3_FCLK;
197 	sc->sc_cfg4 = NCRAMDCFG4_GE12NS | NCRAMDCFG4_RADE;
198 	sc->sc_rev = NCR_VARIANT_AM53C974;
199 	sc->sc_features = NCR_F_FASTSCSI;
200 	sc->sc_cfg3_fscsi = NCRAMDCFG3_FSCSI;
201 	sc->sc_freq = 40; /* MHz */
202 
203 	/*
204 	 * XXX minsync and maxxfer _should_ be set up in MI code,
205 	 * XXX but it appears to have some dependency on what sort
206 	 * XXX of DMA we're hooked up to, etc.
207 	 */
208 
209 	/*
210 	 * This is the value used to start sync negotiations
211 	 * Note that the NCR register "SYNCTP" is programmed
212 	 * in "clocks per byte", and has a minimum value of 4.
213 	 * The SCSI period used in negotiation is one-fourth
214 	 * of the time (in nanoseconds) needed to transfer one byte.
215 	 * Since the chip's clock is given in MHz, we have the following
216 	 * formula: 4 * period = (1000 / freq) * 4
217 	 */
218 
219 	sc->sc_minsync = 1000 / sc->sc_freq;
220 
221 	/* Really no limit, but since we want to fit into the TCR... */
222 	sc->sc_maxxfer = 16 * 1024 * 1024;
223 
224 	/*
225 	 * Create the DMA maps for the data transfers.
226          */
227 
228 #define MDL_SEG_SIZE	0x1000 /* 4kbyte per segment */
229 #define MDL_SEG_OFFSET	0x0FFF
230 #define MDL_SIZE	(MAXPHYS / MDL_SEG_SIZE + 1) /* no hardware limit? */
231 
232 	if (bus_dmamap_create(esc->sc_dmat, MAXPHYS, MDL_SIZE, MDL_SEG_SIZE,
233 	    MDL_SEG_SIZE, BUS_DMA_NOWAIT, &esc->sc_xfermap)) {
234 		printf("%s: can't create dma maps\n", sc->sc_dev.dv_xname);
235 		return;
236 	}
237 
238 	/*
239 	 * Allocate and map memory for the MDL.
240 	 */
241 
242 	if ((error = bus_dmamem_alloc(esc->sc_dmat,
243 	    sizeof(u_int32_t) * MDL_SIZE, PAGE_SIZE, 0, &seg, 1, &rseg,
244 	    BUS_DMA_NOWAIT)) != 0) {
245 		printf("%s: unable to allocate memory for the MDL, "
246 		    "error = %d\n", sc->sc_dev.dv_xname, error);
247 		goto fail_0;
248 	}
249 	if ((error = bus_dmamem_map(esc->sc_dmat, &seg, rseg,
250 	    sizeof(u_int32_t) * MDL_SIZE , (caddr_t *)&esc->sc_mdladdr,
251 	    BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
252 		printf("%s: unable to map the MDL memory, error = %d\n",
253 		    sc->sc_dev.dv_xname, error);
254 		goto fail_1;
255 	}
256 	if ((error = bus_dmamap_create(esc->sc_dmat,
257 	    sizeof(u_int32_t) * MDL_SIZE, 1, sizeof(u_int32_t) * MDL_SIZE,
258 	    0, BUS_DMA_NOWAIT, &esc->sc_mdldmap)) != 0) {
259 		printf("%s: unable to map_create for the MDL, error = %d\n",
260 		    sc->sc_dev.dv_xname, error);
261 		goto fail_2;
262 	}
263 	if ((error = bus_dmamap_load(esc->sc_dmat, esc->sc_mdldmap,
264 	     esc->sc_mdladdr, sizeof(u_int32_t) * MDL_SIZE,
265 	     NULL, BUS_DMA_NOWAIT)) != 0) {
266 		printf("%s: unable to load for the MDL, error = %d\n",
267 		    sc->sc_dev.dv_xname, error);
268 		goto fail_3;
269 	}
270 
271 	/* map and establish interrupt */
272 	if (pci_intr_map(pa, &ih)) {
273 		printf(": couldn't map interrupt\n");
274 		goto fail_4;
275 	}
276 
277 	intrstr = pci_intr_string(pa->pa_pc, ih);
278 	esc->sc_ih = pci_intr_establish(pa->pa_pc, ih, IPL_BIO,
279 	    ncr53c9x_intr, esc, sc->sc_dev.dv_xname);
280 	if (esc->sc_ih == NULL) {
281 		printf(": couldn't establish interrupt");
282 		if (intrstr != NULL)
283 			printf(" at %s", intrstr);
284 		printf("\n");
285 		goto fail_4;
286 	}
287 	if (intrstr != NULL)
288 		printf(": %s\n", intrstr);
289 
290 	/* Do the common parts of attachment. */
291 	printf("%s", sc->sc_dev.dv_xname);
292 
293 	ncr53c9x_attach(sc);
294 
295 	/* Turn on target selection using the `dma' method */
296 	sc->sc_features |= NCR_F_DMASELECT;
297 
298 	return;
299 
300 fail_4:
301 	bus_dmamap_unload(esc->sc_dmat, esc->sc_mdldmap);
302 fail_3:
303 	bus_dmamap_destroy(esc->sc_dmat, esc->sc_mdldmap);
304 fail_2:
305 	bus_dmamem_unmap(esc->sc_dmat, (caddr_t)esc->sc_mdldmap,
306 	    sizeof(uint32_t) * MDL_SIZE);
307 fail_1:
308 	bus_dmamem_free(esc->sc_dmat, &seg, rseg);
309 fail_0:
310 	bus_dmamap_destroy(esc->sc_dmat, esc->sc_xfermap);
311 }
312 
313 /*
314  * Glue functions.
315  */
316 
317 u_char
318 pcscp_read_reg(struct ncr53c9x_softc *sc, int reg)
319 {
320 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
321 
322 	return PCSCP_READ_REG(esc, reg);
323 }
324 
325 void
326 pcscp_write_reg(struct ncr53c9x_softc *sc, int reg, u_char v)
327 {
328 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
329 
330 	PCSCP_WRITE_REG(esc, reg, v);
331 }
332 
333 int
334 pcscp_dma_isintr(struct ncr53c9x_softc *sc)
335 {
336 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
337 
338 	return (PCSCP_READ_REG(esc, NCR_STAT) & NCRSTAT_INT) != 0;
339 }
340 
341 void
342 pcscp_dma_reset(struct ncr53c9x_softc *sc)
343 {
344 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
345 
346 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE);
347 
348 	esc->sc_active = 0;
349 }
350 
351 int
352 pcscp_dma_intr(struct ncr53c9x_softc *sc)
353 {
354 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
355 	int trans, resid, i;
356 	bus_dmamap_t dmap = esc->sc_xfermap;
357 	int datain = esc->sc_datain;
358 	u_int32_t dmastat;
359 	char *p = NULL;
360 
361 	dmastat = READ_DMAREG(esc, DMA_STAT);
362 
363 	if (dmastat & DMASTAT_ERR) {
364 		/* XXX not tested... */
365 		WRITE_DMAREG(esc, DMA_CMD,
366 		    DMACMD_ABORT | (datain ? DMACMD_DIR : 0));
367 
368 		printf("%s: error: DMA error detected; Aborting.\n",
369 		    sc->sc_dev.dv_xname);
370 		bus_dmamap_unload(esc->sc_dmat, dmap);
371 		return -1;
372 	}
373 
374 	if (dmastat & DMASTAT_ABT) {
375 		/* XXX What should be done? */
376 		printf("%s: dma_intr: DMA aborted.\n", sc->sc_dev.dv_xname);
377 		WRITE_DMAREG(esc, DMA_CMD,
378 		    DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
379 		esc->sc_active = 0;
380 		return 0;
381 	}
382 
383 #ifdef DIAGNOSTIC
384 	/* This is an "assertion" :) */
385 	if (esc->sc_active == 0)
386 		panic("pcscp dmaintr: DMA wasn't active");
387 #endif
388 
389 	/* DMA has stopped */
390 
391 	esc->sc_active = 0;
392 
393 	if (esc->sc_dmasize == 0) {
394 		/* A "Transfer Pad" operation completed */
395 		NCR_DMA(("dmaintr: discarded %d bytes (tcl=%d, tcm=%d)\n",
396 		    PCSCP_READ_REG(esc, NCR_TCL) |
397 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8),
398 		    PCSCP_READ_REG(esc, NCR_TCL),
399 		    PCSCP_READ_REG(esc, NCR_TCM)));
400 		return 0;
401 	}
402 
403 	resid = 0;
404 	/*
405 	 * If a transfer onto the SCSI bus gets interrupted by the device
406 	 * (e.g. for a SAVEPOINTER message), the data in the FIFO counts
407 	 * as residual since the ESP counter registers get decremented as
408 	 * bytes are clocked into the FIFO.
409 	 */
410 	if (!datain &&
411 	    (resid = (PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
412 		NCR_DMA(("pcscp_dma_intr: empty esp FIFO of %d ", resid));
413 	}
414 
415 	if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
416 		/*
417 		 * `Terminal count' is off, so read the residue
418 		 * out of the ESP counter registers.
419 		 */
420 		if (datain) {
421 			resid = PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
422 			while (resid > 1)
423 				resid =
424 				    PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
425 			WRITE_DMAREG(esc, DMA_CMD, DMACMD_BLAST | DMACMD_MDL |
426 			    (datain ? DMACMD_DIR : 0));
427 
428 			for (i = 0; i < 0x8000; i++) /* XXX 0x8000 ? */
429 				if (READ_DMAREG(esc, DMA_STAT) & DMASTAT_BCMP)
430 					break;
431 
432 			/* See the below comments... */
433 			if (resid)
434 				p = *esc->sc_dmaaddr;
435 		}
436 
437 		resid += PCSCP_READ_REG(esc, NCR_TCL) |
438 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8) |
439 		    (PCSCP_READ_REG(esc, NCR_TCH) << 16);
440 	} else {
441 		while ((dmastat & DMASTAT_DONE) == 0)
442 			dmastat = READ_DMAREG(esc, DMA_STAT);
443 	}
444 
445 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
446 
447 	/* sync MDL */
448 	bus_dmamap_sync(esc->sc_dmat, esc->sc_mdldmap,
449 	    0, sizeof(u_int32_t) * dmap->dm_nsegs, BUS_DMASYNC_POSTWRITE);
450 	/* sync transfer buffer */
451 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
452 	    datain ? BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
453 	bus_dmamap_unload(esc->sc_dmat, dmap);
454 
455 	trans = esc->sc_dmasize - resid;
456 
457 	/*
458 	 * From the technical manual notes:
459 	 *
460 	 * `In some odd byte conditions, one residual byte will be left
461 	 *  in the SCSI FIFO, and the FIFO flags will never count to 0.
462 	 *  When this happens, the residual byte should be retrieved
463 	 *  via PIO following completion of the BLAST operation.'
464 	 */
465 
466 	if (p) {
467 		p += trans;
468 		*p = PCSCP_READ_REG(esc, NCR_FIFO);
469 		trans++;
470 	}
471 
472 	if (trans < 0) {			/* transferred < 0 ? */
473 #if 0
474 		/*
475 		 * This situation can happen in perfectly normal operation
476 		 * if the ESP is reselected while using DMA to select
477 		 * another target.  As such, don't print the warning.
478 		 */
479 		printf("%s: xfer (%d) > req (%d)\n",
480 		    sc->sc_dev.dv_xname, trans, esc->sc_dmasize);
481 #endif
482 		trans = esc->sc_dmasize;
483 	}
484 
485 	NCR_DMA(("dmaintr: tcl=%d, tcm=%d, tch=%d; trans=%d, resid=%d\n",
486 	    PCSCP_READ_REG(esc, NCR_TCL),
487 	    PCSCP_READ_REG(esc, NCR_TCM),
488 	    PCSCP_READ_REG(esc, NCR_TCH),
489 	    trans, resid));
490 
491 	*esc->sc_dmalen -= trans;
492 	*esc->sc_dmaaddr += trans;
493 
494 	return 0;
495 }
496 
497 int
498 pcscp_dma_setup(struct ncr53c9x_softc *sc, caddr_t *addr, size_t *len,
499     int datain, size_t *dmasize)
500 {
501 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
502 	bus_dmamap_t dmap = esc->sc_xfermap;
503 	u_int32_t *mdl;
504 	int error, nseg, seg;
505 	bus_addr_t s_offset, s_addr;
506 
507 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
508 
509 	esc->sc_dmaaddr = addr;
510 	esc->sc_dmalen = len;
511 	esc->sc_dmasize = *dmasize;
512 	esc->sc_datain = datain;
513 
514 #ifdef DIAGNOSTIC
515 	if ((*dmasize / MDL_SEG_SIZE) > MDL_SIZE)
516 		panic("pcscp: transfer size too large");
517 #endif
518 
519 	/*
520 	 * No need to set up DMA in `Transfer Pad' operation.
521 	 * (case of *dmasize == 0)
522 	 */
523 	if (*dmasize == 0)
524 		return 0;
525 
526 	error = bus_dmamap_load(esc->sc_dmat, dmap, *esc->sc_dmaaddr,
527 	    *esc->sc_dmalen, NULL,
528 	    ((sc->sc_nexus->xs->flags & SCSI_NOSLEEP) ?
529 	    BUS_DMA_NOWAIT : BUS_DMA_WAITOK) | BUS_DMA_STREAMING |
530 	    ((sc->sc_nexus->xs->flags & SCSI_DATA_IN) ?
531 	     BUS_DMA_READ : BUS_DMA_WRITE));
532 	if (error) {
533 		printf("%s: unable to load dmamap, error = %d\n",
534 		    sc->sc_dev.dv_xname, error);
535 		return error;
536 	}
537 
538 	/* set transfer length */
539 	WRITE_DMAREG(esc, DMA_STC, *dmasize);
540 
541 	/* set up MDL */
542 	mdl = esc->sc_mdladdr;
543 	nseg = dmap->dm_nsegs;
544 
545 	/* the first segment is possibly not aligned with 4k MDL boundary */
546 	s_addr = dmap->dm_segs[0].ds_addr;
547 	s_offset = s_addr & MDL_SEG_OFFSET;
548 	s_addr -= s_offset;
549 
550 	/* set the first MDL and offset */
551 	WRITE_DMAREG(esc, DMA_SPA, s_offset);
552 	*mdl++ = htole32(s_addr);
553 
554 	/* the rest dmamap segments are aligned with 4k boundary */
555 	for (seg = 1; seg < nseg; seg++)
556 		*mdl++ = htole32(dmap->dm_segs[seg].ds_addr);
557 
558 	return 0;
559 }
560 
561 void
562 pcscp_dma_go(struct ncr53c9x_softc *sc)
563 {
564 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
565 	bus_dmamap_t dmap = esc->sc_xfermap, mdldmap = esc->sc_mdldmap;
566 	int datain = esc->sc_datain;
567 
568 	/* No DMA transfer in Transfer Pad operation */
569 	if (esc->sc_dmasize == 0)
570 		return;
571 
572 	/* sync transfer buffer */
573 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
574 	    datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
575 
576 	/* sync MDL */
577 	bus_dmamap_sync(esc->sc_dmat, mdldmap,
578 	    0, sizeof(u_int32_t) * dmap->dm_nsegs, BUS_DMASYNC_PREWRITE);
579 
580 	/* set Starting MDL Address */
581 	WRITE_DMAREG(esc, DMA_SMDLA, mdldmap->dm_segs[0].ds_addr);
582 
583 	/* set DMA command register bits */
584 	/* XXX DMA Transfer Interrupt Enable bit is broken? */
585 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | DMACMD_MDL |
586 	    /* DMACMD_INTE | */
587 	    (datain ? DMACMD_DIR : 0));
588 
589 	/* issue DMA start command */
590 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_START | DMACMD_MDL |
591 	    /* DMACMD_INTE | */
592 	    (datain ? DMACMD_DIR : 0));
593 
594 	esc->sc_active = 1;
595 }
596 
597 void
598 pcscp_dma_stop(struct ncr53c9x_softc *sc)
599 {
600 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
601 
602 	/* dma stop */
603 	/* XXX What should we do here ? */
604 	WRITE_DMAREG(esc, DMA_CMD,
605 	    DMACMD_ABORT | (esc->sc_datain ? DMACMD_DIR : 0));
606 	bus_dmamap_unload(esc->sc_dmat, esc->sc_xfermap);
607 
608 	esc->sc_active = 0;
609 }
610 
611 int
612 pcscp_dma_isactive(struct ncr53c9x_softc *sc)
613 {
614 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
615 
616 	/* XXX should check esc->sc_active? */
617 	if ((READ_DMAREG(esc, DMA_CMD) & DMACMD_CMD) != DMACMD_IDLE)
618 		return 1;
619 	return 0;
620 }
621