xref: /netbsd-src/sys/dev/pci/pcscp.c (revision 8ac07aec990b9d2e483062509d0a9fa5b4f57cf2)
1 /*	$NetBSD: pcscp.c,v 1.42 2008/04/13 04:55:53 tsutsui Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center; Izumi Tsutsui.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the NetBSD
22  *	Foundation, Inc. and its contributors.
23  * 4. Neither the name of The NetBSD Foundation nor the names of its
24  *    contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /*
41  * pcscp.c: device dependent code for AMD Am53c974 (PCscsi-PCI)
42  * written by Izumi Tsutsui <tsutsui@NetBSD.org>
43  */
44 
45 #include <sys/cdefs.h>
46 __KERNEL_RCSID(0, "$NetBSD: pcscp.c,v 1.42 2008/04/13 04:55:53 tsutsui Exp $");
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/device.h>
51 #include <sys/buf.h>
52 
53 #include <sys/bus.h>
54 #include <sys/intr.h>
55 
56 #include <uvm/uvm_extern.h>
57 
58 #include <dev/scsipi/scsipi_all.h>
59 #include <dev/scsipi/scsi_all.h>
60 #include <dev/scsipi/scsiconf.h>
61 
62 #include <dev/pci/pcireg.h>
63 #include <dev/pci/pcivar.h>
64 #include <dev/pci/pcidevs.h>
65 
66 #include <dev/ic/ncr53c9xreg.h>
67 #include <dev/ic/ncr53c9xvar.h>
68 
69 #include <dev/pci/pcscpreg.h>
70 
71 #define IO_MAP_REG	0x10
72 
73 struct pcscp_softc {
74 	struct ncr53c9x_softc sc_ncr53c9x;	/* glue to MI code */
75 
76 	bus_space_tag_t sc_st;		/* bus space tag */
77 	bus_space_handle_t sc_sh;	/* bus space handle */
78 	void *sc_ih;			/* interrupt cookie */
79 
80 	bus_dma_tag_t sc_dmat;		/* DMA tag */
81 
82 	bus_dmamap_t sc_xfermap;	/* DMA map for transfers */
83 
84 	uint32_t *sc_mdladdr;		/* MDL array */
85 	bus_dmamap_t sc_mdldmap;	/* MDL DMA map */
86 
87 	int	sc_active;		/* DMA state */
88 	int	sc_datain;		/* DMA Data Direction */
89 	size_t	sc_dmasize;		/* DMA size */
90 	uint8_t	**sc_dmaaddr;		/* DMA address */
91 	size_t	*sc_dmalen;		/* DMA length */
92 };
93 
94 #define	READ_DMAREG(sc, reg) \
95 	bus_space_read_4((sc)->sc_st, (sc)->sc_sh, (reg))
96 #define	WRITE_DMAREG(sc, reg, var) \
97 	bus_space_write_4((sc)->sc_st, (sc)->sc_sh, (reg), (var))
98 
99 #define	PCSCP_READ_REG(sc, reg)	\
100 	bus_space_read_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2)
101 #define	PCSCP_WRITE_REG(sc, reg, val)	\
102 	bus_space_write_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2, (val))
103 
104 
105 static int pcscp_match(device_t, cfdata_t, void *);
106 static void pcscp_attach(device_t, device_t, void *);
107 
108 CFATTACH_DECL_NEW(pcscp, sizeof(struct pcscp_softc),
109     pcscp_match, pcscp_attach, NULL, NULL);
110 
111 /*
112  * Functions and the switch for the MI code.
113  */
114 
115 static uint8_t	pcscp_read_reg(struct ncr53c9x_softc *, int);
116 static void	pcscp_write_reg(struct ncr53c9x_softc *, int, uint8_t);
117 static int	pcscp_dma_isintr(struct ncr53c9x_softc *);
118 static void	pcscp_dma_reset(struct ncr53c9x_softc *);
119 static int	pcscp_dma_intr(struct ncr53c9x_softc *);
120 static int	pcscp_dma_setup(struct ncr53c9x_softc *, uint8_t **, size_t *,
121 		    int, size_t *);
122 static void	pcscp_dma_go(struct ncr53c9x_softc *);
123 static void	pcscp_dma_stop(struct ncr53c9x_softc *);
124 static int	pcscp_dma_isactive(struct ncr53c9x_softc *);
125 
126 static struct ncr53c9x_glue pcscp_glue = {
127 	pcscp_read_reg,
128 	pcscp_write_reg,
129 	pcscp_dma_isintr,
130 	pcscp_dma_reset,
131 	pcscp_dma_intr,
132 	pcscp_dma_setup,
133 	pcscp_dma_go,
134 	pcscp_dma_stop,
135 	pcscp_dma_isactive,
136 	NULL,			/* gl_clear_latched_intr */
137 };
138 
139 static int
140 pcscp_match(device_t parent, cfdata_t cf, void *aux)
141 {
142 	struct pci_attach_args *pa = aux;
143 
144 	if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_AMD)
145 		return 0;
146 
147 	switch (PCI_PRODUCT(pa->pa_id)) {
148 	case PCI_PRODUCT_AMD_PCSCSI_PCI:
149 		return 1;
150 	}
151 	return 0;
152 }
153 
154 /*
155  * Attach this instance, and then all the sub-devices
156  */
157 static void
158 pcscp_attach(device_t parent, device_t self, void *aux)
159 {
160 	struct pcscp_softc *esc = device_private(self);
161 	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
162 	struct pci_attach_args *pa = aux;
163 	bus_space_tag_t iot;
164 	bus_space_handle_t ioh;
165 	pci_intr_handle_t ih;
166 	const char *intrstr;
167 	pcireg_t csr;
168 	bus_dma_segment_t seg;
169 	int error, rseg;
170 	char devinfo[256];
171 
172 	sc->sc_dev = self;
173 	pci_devinfo(pa->pa_id, pa->pa_class, 0, devinfo, sizeof(devinfo));
174 	aprint_normal(": %s\n", devinfo);
175 	aprint_normal("%s", device_xname(sc->sc_dev));
176 
177 	if (pci_mapreg_map(pa, IO_MAP_REG, PCI_MAPREG_TYPE_IO, 0,
178 	    &iot, &ioh, NULL, NULL)) {
179 		aprint_error(": unable to map registers\n");
180 		return;
181 	}
182 
183 	sc->sc_glue = &pcscp_glue;
184 
185 	esc->sc_st = iot;
186 	esc->sc_sh = ioh;
187 	esc->sc_dmat = pa->pa_dmat;
188 
189 	csr = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG);
190 	pci_conf_write(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG,
191 	    csr | PCI_COMMAND_MASTER_ENABLE | PCI_COMMAND_IO_ENABLE);
192 
193 	/*
194 	 * XXX More of this should be in ncr53c9x_attach(), but
195 	 * XXX should we really poke around the chip that much in
196 	 * XXX the MI code?  Think about this more...
197 	 */
198 
199 	/*
200 	 * Set up static configuration info.
201 	 */
202 
203 	/*
204 	 * XXX should read configuration from EEPROM?
205 	 *
206 	 * MI ncr53c9x driver does not support configuration
207 	 * per each target device, though...
208 	 */
209 	sc->sc_id = 7;
210 	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
211 	sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_FE;
212 	sc->sc_cfg3 = NCRAMDCFG3_IDM | NCRAMDCFG3_FCLK;
213 	sc->sc_cfg4 = NCRAMDCFG4_GE12NS | NCRAMDCFG4_RADE;
214 	sc->sc_rev = NCR_VARIANT_AM53C974;
215 	sc->sc_features = NCR_F_FASTSCSI;
216 	sc->sc_cfg3_fscsi = NCRAMDCFG3_FSCSI;
217 	sc->sc_freq = 40; /* MHz */
218 
219 	/*
220 	 * XXX minsync and maxxfer _should_ be set up in MI code,
221 	 * XXX but it appears to have some dependency on what sort
222 	 * XXX of DMA we're hooked up to, etc.
223 	 */
224 
225 	/*
226 	 * This is the value used to start sync negotiations
227 	 * Note that the NCR register "SYNCTP" is programmed
228 	 * in "clocks per byte", and has a minimum value of 4.
229 	 * The SCSI period used in negotiation is one-fourth
230 	 * of the time (in nanoseconds) needed to transfer one byte.
231 	 * Since the chip's clock is given in MHz, we have the following
232 	 * formula: 4 * period = (1000 / freq) * 4
233 	 */
234 
235 	sc->sc_minsync = 1000 / sc->sc_freq;
236 
237 	/* Really no limit, but since we want to fit into the TCR... */
238 	sc->sc_maxxfer = 16 * 1024 * 1024;
239 
240 	/*
241 	 * Create the DMA maps for the data transfers.
242 	 */
243 
244 #define MDL_SEG_SIZE	0x1000 /* 4kbyte per segment */
245 #define MDL_SEG_OFFSET	0x0FFF
246 #define MDL_SIZE	(MAXPHYS / MDL_SEG_SIZE + 1) /* no hardware limit? */
247 
248 	if (bus_dmamap_create(esc->sc_dmat, MAXPHYS, MDL_SIZE, MDL_SEG_SIZE,
249 	    MDL_SEG_SIZE, BUS_DMA_NOWAIT, &esc->sc_xfermap)) {
250 		aprint_error(": can't create DMA maps\n");
251 		return;
252 	}
253 
254 	/*
255 	 * Allocate and map memory for the MDL.
256 	 */
257 
258 	if ((error = bus_dmamem_alloc(esc->sc_dmat,
259 	    sizeof(uint32_t) * MDL_SIZE, PAGE_SIZE, 0, &seg, 1, &rseg,
260 	    BUS_DMA_NOWAIT)) != 0) {
261 		aprint_error(": unable to allocate memory for the MDL,"
262 		    " error = %d\n", error);
263 		goto fail_0;
264 	}
265 	if ((error = bus_dmamem_map(esc->sc_dmat, &seg, rseg,
266 	    sizeof(uint32_t) * MDL_SIZE , (void **)&esc->sc_mdladdr,
267 	    BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
268 		aprint_error(": unable to map the MDL memory, error = %d\n",
269 		    error);
270 		goto fail_1;
271 	}
272 	if ((error = bus_dmamap_create(esc->sc_dmat,
273 	    sizeof(uint32_t) * MDL_SIZE, 1, sizeof(uint32_t) * MDL_SIZE,
274 	    0, BUS_DMA_NOWAIT, &esc->sc_mdldmap)) != 0) {
275 		aprint_error(": unable to map_create for the MDL, error = %d\n",
276 		    error);
277 		goto fail_2;
278 	}
279 	if ((error = bus_dmamap_load(esc->sc_dmat, esc->sc_mdldmap,
280 	     esc->sc_mdladdr, sizeof(uint32_t) * MDL_SIZE,
281 	     NULL, BUS_DMA_NOWAIT)) != 0) {
282 		aprint_error(": unable to load for the MDL, error = %d\n",
283 		    error);
284 		goto fail_3;
285 	}
286 
287 	/* map and establish interrupt */
288 	if (pci_intr_map(pa, &ih)) {
289 		aprint_error(": couldn't map interrupt\n");
290 		goto fail_4;
291 	}
292 
293 	intrstr = pci_intr_string(pa->pa_pc, ih);
294 	esc->sc_ih = pci_intr_establish(pa->pa_pc, ih, IPL_BIO,
295 	    ncr53c9x_intr, esc);
296 	if (esc->sc_ih == NULL) {
297 		aprint_error(": couldn't establish interrupt");
298 		if (intrstr != NULL)
299 			aprint_error(" at %s", intrstr);
300 		aprint_error("\n");
301 		goto fail_4;
302 	}
303 	if (intrstr != NULL) {
304 		aprint_normal(": interrupting at %s\n", intrstr);
305 		aprint_normal("%s", device_xname(sc->sc_dev));
306 	}
307 
308 	/* Do the common parts of attachment. */
309 	sc->sc_adapter.adapt_minphys = minphys;
310 	sc->sc_adapter.adapt_request = ncr53c9x_scsipi_request;
311 	ncr53c9x_attach(sc);
312 
313 	/* Turn on target selection using the `DMA' method */
314 	sc->sc_features |= NCR_F_DMASELECT;
315 
316 	return;
317 
318  fail_4:
319 	bus_dmamap_unload(esc->sc_dmat, esc->sc_mdldmap);
320  fail_3:
321 	bus_dmamap_destroy(esc->sc_dmat, esc->sc_mdldmap);
322  fail_2:
323 	bus_dmamem_unmap(esc->sc_dmat, (void *)esc->sc_mdldmap,
324 	    sizeof(uint32_t) * MDL_SIZE);
325  fail_1:
326 	bus_dmamem_free(esc->sc_dmat, &seg, rseg);
327  fail_0:
328 	bus_dmamap_destroy(esc->sc_dmat, esc->sc_xfermap);
329 }
330 
331 /*
332  * Glue functions.
333  */
334 
335 static uint8_t
336 pcscp_read_reg(struct ncr53c9x_softc *sc, int reg)
337 {
338 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
339 
340 	return PCSCP_READ_REG(esc, reg);
341 }
342 
343 static void
344 pcscp_write_reg(struct ncr53c9x_softc *sc, int reg, uint8_t v)
345 {
346 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
347 
348 	PCSCP_WRITE_REG(esc, reg, v);
349 }
350 
351 static int
352 pcscp_dma_isintr(struct ncr53c9x_softc *sc)
353 {
354 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
355 
356 	return (PCSCP_READ_REG(esc, NCR_STAT) & NCRSTAT_INT) != 0;
357 }
358 
359 static void
360 pcscp_dma_reset(struct ncr53c9x_softc *sc)
361 {
362 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
363 
364 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE);
365 
366 	esc->sc_active = 0;
367 }
368 
369 static int
370 pcscp_dma_intr(struct ncr53c9x_softc *sc)
371 {
372 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
373 	int trans, resid, i;
374 	bus_dmamap_t dmap = esc->sc_xfermap;
375 	int datain = esc->sc_datain;
376 	uint32_t dmastat;
377 	uint8_t *p = NULL;
378 
379 	dmastat = READ_DMAREG(esc, DMA_STAT);
380 
381 	if (dmastat & DMASTAT_ERR) {
382 		/* XXX not tested... */
383 		WRITE_DMAREG(esc, DMA_CMD,
384 		    DMACMD_ABORT | (datain ? DMACMD_DIR : 0));
385 
386 		printf("%s: error: DMA error detected; Aborting.\n",
387 		    device_xname(sc->sc_dev));
388 		bus_dmamap_unload(esc->sc_dmat, dmap);
389 		return -1;
390 	}
391 
392 	if (dmastat & DMASTAT_ABT) {
393 		/* XXX What should be done? */
394 		printf("%s: %s: DMA aborted.\n",
395 		    device_xname(sc->sc_dev), __func__);
396 		WRITE_DMAREG(esc, DMA_CMD,
397 		    DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
398 		esc->sc_active = 0;
399 		return 0;
400 	}
401 
402 #ifdef DIAGNOSTIC
403 	/* This is an "assertion" :) */
404 	if (esc->sc_active == 0)
405 		panic("%s: %s: DMA wasn't active",
406 		    device_xname(sc->sc_dev), __func__);
407 #endif
408 
409 	/* DMA has stopped */
410 
411 	esc->sc_active = 0;
412 
413 	if (esc->sc_dmasize == 0) {
414 		/* A "Transfer Pad" operation completed */
415 		NCR_DMA(("%s: discarded %d bytes (tcl=%d, tcm=%d)\n",
416 		    __func__,
417 		    PCSCP_READ_REG(esc, NCR_TCL) |
418 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8),
419 		    PCSCP_READ_REG(esc, NCR_TCL),
420 		    PCSCP_READ_REG(esc, NCR_TCM)));
421 		return 0;
422 	}
423 
424 	resid = 0;
425 	/*
426 	 * If a transfer onto the SCSI bus gets interrupted by the device
427 	 * (e.g. for a SAVEPOINTER message), the data in the FIFO counts
428 	 * as residual since the ESP counter registers get decremented as
429 	 * bytes are clocked into the FIFO.
430 	 */
431 	if (!datain &&
432 	    (resid = (PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
433 		NCR_DMA(("%s: empty esp FIFO of %d ", __func__, resid));
434 	}
435 
436 	if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
437 		/*
438 		 * `Terminal count' is off, so read the residue
439 		 * out of the ESP counter registers.
440 		 */
441 		if (datain) {
442 			resid = PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
443 			while (resid > 1)
444 				resid =
445 				    PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
446 			WRITE_DMAREG(esc, DMA_CMD, DMACMD_BLAST | DMACMD_MDL |
447 			    (datain ? DMACMD_DIR : 0));
448 
449 			for (i = 0; i < 1000; i++) { /* XXX */
450 				if (READ_DMAREG(esc, DMA_STAT) & DMASTAT_BCMP)
451 					break;
452 				DELAY(1);
453 			}
454 
455 			/* See the below comments... */
456 			if (resid)
457 				p = *esc->sc_dmaaddr;
458 		}
459 
460 		resid += PCSCP_READ_REG(esc, NCR_TCL) |
461 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8) |
462 		    (PCSCP_READ_REG(esc, NCR_TCH) << 16);
463 	} else {
464 		while ((dmastat & DMASTAT_DONE) == 0)
465 			dmastat = READ_DMAREG(esc, DMA_STAT);
466 	}
467 
468 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
469 
470 	/* sync MDL */
471 	bus_dmamap_sync(esc->sc_dmat, esc->sc_mdldmap,
472 	    0, sizeof(uint32_t) * dmap->dm_nsegs, BUS_DMASYNC_POSTWRITE);
473 	/* sync transfer buffer */
474 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
475 	    datain ? BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
476 	bus_dmamap_unload(esc->sc_dmat, dmap);
477 
478 	trans = esc->sc_dmasize - resid;
479 
480 	/*
481 	 * From the technical manual notes:
482 	 *
483 	 * `In some odd byte conditions, one residual byte will be left
484 	 *  in the SCSI FIFO, and the FIFO flags will never count to 0.
485 	 *  When this happens, the residual byte should be retrieved
486 	 *  via PIO following completion of the BLAST operation.'
487 	 */
488 
489 	if (p) {
490 		p += trans;
491 		*p = PCSCP_READ_REG(esc, NCR_FIFO);
492 		trans++;
493 	}
494 
495 	if (trans < 0) {			/* transferred < 0 ? */
496 #if 0
497 		/*
498 		 * This situation can happen in perfectly normal operation
499 		 * if the ESP is reselected while using DMA to select
500 		 * another target.  As such, don't print the warning.
501 		 */
502 		printf("%s: xfer (%d) > req (%d)\n",
503 		    device_xname(sc->sc_dev), trans, esc->sc_dmasize);
504 #endif
505 		trans = esc->sc_dmasize;
506 	}
507 
508 	NCR_DMA(("%s: tcl=%d, tcm=%d, tch=%d; trans=%d, resid=%d\n",
509 	    __func__,
510 	    PCSCP_READ_REG(esc, NCR_TCL),
511 	    PCSCP_READ_REG(esc, NCR_TCM),
512 	    PCSCP_READ_REG(esc, NCR_TCH),
513 	    trans, resid));
514 
515 	*esc->sc_dmalen -= trans;
516 	*esc->sc_dmaaddr += trans;
517 
518 	return 0;
519 }
520 
521 static int
522 pcscp_dma_setup(struct ncr53c9x_softc *sc, uint8_t **addr, size_t *len,
523     int datain, size_t *dmasize)
524 {
525 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
526 	bus_dmamap_t dmap = esc->sc_xfermap;
527 	uint32_t *mdl;
528 	int error, nseg, seg;
529 	bus_addr_t s_offset, s_addr;
530 
531 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
532 
533 	esc->sc_dmaaddr = addr;
534 	esc->sc_dmalen = len;
535 	esc->sc_dmasize = *dmasize;
536 	esc->sc_datain = datain;
537 
538 #ifdef DIAGNOSTIC
539 	if ((*dmasize / MDL_SEG_SIZE) > MDL_SIZE)
540 		panic("%s: transfer size too large", device_xname(sc->sc_dev));
541 #endif
542 
543 	/*
544 	 * No need to set up DMA in `Transfer Pad' operation.
545 	 * (case of *dmasize == 0)
546 	 */
547 	if (*dmasize == 0)
548 		return 0;
549 
550 	error = bus_dmamap_load(esc->sc_dmat, dmap, *esc->sc_dmaaddr,
551 	    *esc->sc_dmalen, NULL,
552 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_NOSLEEP) ?
553 	    BUS_DMA_NOWAIT : BUS_DMA_WAITOK) | BUS_DMA_STREAMING |
554 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_DATA_IN) ?
555 	     BUS_DMA_READ : BUS_DMA_WRITE));
556 	if (error) {
557 		printf("%s: unable to load dmamap, error = %d\n",
558 		    device_xname(sc->sc_dev), error);
559 		return error;
560 	}
561 
562 	/* set transfer length */
563 	WRITE_DMAREG(esc, DMA_STC, *dmasize);
564 
565 	/* set up MDL */
566 	mdl = esc->sc_mdladdr;
567 	nseg = dmap->dm_nsegs;
568 
569 	/* the first segment is possibly not aligned with 4k MDL boundary */
570 	s_addr = dmap->dm_segs[0].ds_addr;
571 	s_offset = s_addr & MDL_SEG_OFFSET;
572 	s_addr -= s_offset;
573 
574 	/* set the first MDL and offset */
575 	WRITE_DMAREG(esc, DMA_SPA, s_offset);
576 	*mdl++ = htole32(s_addr);
577 
578 	/* the rest dmamap segments are aligned with 4k boundary */
579 	for (seg = 1; seg < nseg; seg++)
580 		*mdl++ = htole32(dmap->dm_segs[seg].ds_addr);
581 
582 	return 0;
583 }
584 
585 static void
586 pcscp_dma_go(struct ncr53c9x_softc *sc)
587 {
588 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
589 	bus_dmamap_t dmap = esc->sc_xfermap, mdldmap = esc->sc_mdldmap;
590 	int datain = esc->sc_datain;
591 
592 	/* No DMA transfer in Transfer Pad operation */
593 	if (esc->sc_dmasize == 0)
594 		return;
595 
596 	/* sync transfer buffer */
597 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
598 	    datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
599 
600 	/* sync MDL */
601 	bus_dmamap_sync(esc->sc_dmat, mdldmap,
602 	    0, sizeof(uint32_t) * dmap->dm_nsegs, BUS_DMASYNC_PREWRITE);
603 
604 	/* set Starting MDL Address */
605 	WRITE_DMAREG(esc, DMA_SMDLA, mdldmap->dm_segs[0].ds_addr);
606 
607 	/* set DMA command register bits */
608 	/* XXX DMA Transfer Interrupt Enable bit is broken? */
609 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | DMACMD_MDL |
610 	    /* DMACMD_INTE | */
611 	    (datain ? DMACMD_DIR : 0));
612 
613 	/* issue DMA start command */
614 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_START | DMACMD_MDL |
615 	    /* DMACMD_INTE | */
616 	    (datain ? DMACMD_DIR : 0));
617 
618 	esc->sc_active = 1;
619 }
620 
621 static void
622 pcscp_dma_stop(struct ncr53c9x_softc *sc)
623 {
624 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
625 
626 	/* DMA stop */
627 	/* XXX What should we do here ? */
628 	WRITE_DMAREG(esc, DMA_CMD,
629 	    DMACMD_ABORT | (esc->sc_datain ? DMACMD_DIR : 0));
630 	bus_dmamap_unload(esc->sc_dmat, esc->sc_xfermap);
631 
632 	esc->sc_active = 0;
633 }
634 
635 static int
636 pcscp_dma_isactive(struct ncr53c9x_softc *sc)
637 {
638 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
639 
640 	/* XXX should check esc->sc_active? */
641 	if ((READ_DMAREG(esc, DMA_CMD) & DMACMD_CMD) != DMACMD_IDLE)
642 		return 1;
643 	return 0;
644 }
645