xref: /netbsd-src/sys/dev/pci/pcscp.c (revision 4b896b232495b7a9b8b94a1cf1e21873296d53b8)
1 /*	$NetBSD: pcscp.c,v 1.29 2004/04/23 21:13:07 itojun 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@ceres.dti.ne.jp>
43  *
44  * Technical manual available at
45  * http://www.amd.com/files/connectivitysolutions/networking/archivednetworking/19113.pdf
46  */
47 
48 #include <sys/cdefs.h>
49 __KERNEL_RCSID(0, "$NetBSD: pcscp.c,v 1.29 2004/04/23 21:13:07 itojun Exp $");
50 
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/device.h>
54 #include <sys/buf.h>
55 
56 #include <machine/bus.h>
57 #include <machine/intr.h>
58 
59 #include <uvm/uvm_extern.h>
60 
61 #include <dev/scsipi/scsipi_all.h>
62 #include <dev/scsipi/scsi_all.h>
63 #include <dev/scsipi/scsiconf.h>
64 
65 #include <dev/pci/pcireg.h>
66 #include <dev/pci/pcivar.h>
67 #include <dev/pci/pcidevs.h>
68 
69 #include <dev/ic/ncr53c9xreg.h>
70 #include <dev/ic/ncr53c9xvar.h>
71 
72 #include <dev/pci/pcscpreg.h>
73 
74 #define IO_MAP_REG	0x10
75 
76 struct pcscp_softc {
77 	struct ncr53c9x_softc sc_ncr53c9x;	/* glue to MI code */
78 
79 	bus_space_tag_t sc_st;		/* bus space tag */
80 	bus_space_handle_t sc_sh;	/* bus space handle */
81 	void *sc_ih;			/* interrupt cookie */
82 
83 	bus_dma_tag_t sc_dmat;		/* DMA tag */
84 
85 	bus_dmamap_t sc_xfermap;	/* DMA map for transfers */
86 
87 	u_int32_t *sc_mdladdr;		/* MDL array */
88 	bus_dmamap_t sc_mdldmap;	/* MDL DMA map */
89 
90 	int	sc_active;		/* DMA state */
91 	int	sc_datain;		/* DMA Data Direction */
92 	size_t	sc_dmasize;		/* DMA size */
93 	char	**sc_dmaaddr;		/* DMA address */
94 	size_t	*sc_dmalen;		/* DMA length */
95 };
96 
97 #define	READ_DMAREG(sc, reg) \
98 	bus_space_read_4((sc)->sc_st, (sc)->sc_sh, (reg))
99 #define	WRITE_DMAREG(sc, reg, var) \
100 	bus_space_write_4((sc)->sc_st, (sc)->sc_sh, (reg), (var))
101 
102 #define	PCSCP_READ_REG(sc, reg)	\
103 	bus_space_read_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2)
104 #define	PCSCP_WRITE_REG(sc, reg, val)	\
105 	bus_space_write_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2, (val))
106 
107 int	pcscp_match(struct device *, struct cfdata *, void *);
108 void	pcscp_attach(struct device *, struct device *, void *);
109 
110 CFATTACH_DECL(pcscp, sizeof(struct pcscp_softc),
111     pcscp_match, pcscp_attach, NULL, NULL);
112 
113 /*
114  * Functions and the switch for the MI code.
115  */
116 
117 u_char	pcscp_read_reg(struct ncr53c9x_softc *, int);
118 void	pcscp_write_reg(struct ncr53c9x_softc *, int, u_char);
119 int	pcscp_dma_isintr(struct ncr53c9x_softc *);
120 void	pcscp_dma_reset(struct ncr53c9x_softc *);
121 int	pcscp_dma_intr(struct ncr53c9x_softc *);
122 int	pcscp_dma_setup(struct ncr53c9x_softc *, caddr_t *, size_t *, int,
123     size_t *);
124 void	pcscp_dma_go(struct ncr53c9x_softc *);
125 void	pcscp_dma_stop(struct ncr53c9x_softc *);
126 int	pcscp_dma_isactive(struct ncr53c9x_softc *);
127 
128 struct ncr53c9x_glue pcscp_glue = {
129 	pcscp_read_reg,
130 	pcscp_write_reg,
131 	pcscp_dma_isintr,
132 	pcscp_dma_reset,
133 	pcscp_dma_intr,
134 	pcscp_dma_setup,
135 	pcscp_dma_go,
136 	pcscp_dma_stop,
137 	pcscp_dma_isactive,
138 	NULL,			/* gl_clear_latched_intr */
139 };
140 
141 int
142 pcscp_match(parent, match, aux)
143 	struct device *parent;
144 	struct cfdata *match;
145 	void *aux;
146 {
147 	struct pci_attach_args *pa = aux;
148 	if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_AMD)
149 		return 0;
150 
151 	switch (PCI_PRODUCT(pa->pa_id)) {
152 	case PCI_PRODUCT_AMD_PCSCSI_PCI:
153 		return 1;
154 	}
155 	return 0;
156 }
157 
158 /*
159  * Attach this instance, and then all the sub-devices
160  */
161 void
162 pcscp_attach(parent, self, aux)
163 	struct device *parent, *self;
164 	void *aux;
165 {
166 	struct pci_attach_args *pa = aux;
167 	struct pcscp_softc *esc = (void *)self;
168 	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
169 	bus_space_tag_t iot;
170 	bus_space_handle_t ioh;
171 	pci_intr_handle_t ih;
172 	const char *intrstr;
173 	pcireg_t csr;
174 	bus_dma_segment_t seg;
175 	int error, rseg;
176 	char devinfo[256];
177 
178 	pci_devinfo(pa->pa_id, pa->pa_class, 0, devinfo, sizeof(devinfo));
179 	printf(": %s\n", devinfo);
180 	printf("%s", sc->sc_dev.dv_xname);
181 
182 	if (pci_mapreg_map(pa, IO_MAP_REG, PCI_MAPREG_TYPE_IO, 0,
183 	    &iot, &ioh, NULL, NULL)) {
184 		printf(": unable to map registers\n");
185 		return;
186 	}
187 
188 	sc->sc_glue = &pcscp_glue;
189 
190 	esc->sc_st = iot;
191 	esc->sc_sh = ioh;
192 	esc->sc_dmat = pa->pa_dmat;
193 
194 	csr = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG);
195 	pci_conf_write(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG,
196 	    csr | PCI_COMMAND_MASTER_ENABLE | PCI_COMMAND_IO_ENABLE);
197 
198 	/*
199 	 * XXX More of this should be in ncr53c9x_attach(), but
200 	 * XXX should we really poke around the chip that much in
201 	 * XXX the MI code?  Think about this more...
202 	 */
203 
204 	/*
205 	 * Set up static configuration info.
206 	 */
207 
208 	/*
209 	 * XXX should read configuration from EEPROM?
210 	 *
211 	 * MI ncr53c9x driver does not support configuration
212 	 * per each target device, though...
213 	 */
214 	sc->sc_id = 7;
215 	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
216 	sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_FE;
217 	sc->sc_cfg3 = NCRAMDCFG3_IDM | NCRAMDCFG3_FCLK;
218 	sc->sc_cfg4 = NCRAMDCFG4_GE12NS | NCRAMDCFG4_RADE;
219 	sc->sc_rev = NCR_VARIANT_AM53C974;
220 	sc->sc_features = NCR_F_FASTSCSI;
221 	sc->sc_cfg3_fscsi = NCRAMDCFG3_FSCSI;
222 	sc->sc_freq = 40; /* MHz */
223 
224 	/*
225 	 * XXX minsync and maxxfer _should_ be set up in MI code,
226 	 * XXX but it appears to have some dependency on what sort
227 	 * XXX of DMA we're hooked up to, etc.
228 	 */
229 
230 	/*
231 	 * This is the value used to start sync negotiations
232 	 * Note that the NCR register "SYNCTP" is programmed
233 	 * in "clocks per byte", and has a minimum value of 4.
234 	 * The SCSI period used in negotiation is one-fourth
235 	 * of the time (in nanoseconds) needed to transfer one byte.
236 	 * Since the chip's clock is given in MHz, we have the following
237 	 * formula: 4 * period = (1000 / freq) * 4
238 	 */
239 
240 	sc->sc_minsync = 1000 / sc->sc_freq;
241 
242 	/* Really no limit, but since we want to fit into the TCR... */
243 	sc->sc_maxxfer = 16 * 1024 * 1024;
244 
245 	/*
246 	 * Create the DMA maps for the data transfers.
247 	 */
248 
249 #define MDL_SEG_SIZE	0x1000 /* 4kbyte per segment */
250 #define MDL_SEG_OFFSET	0x0FFF
251 #define MDL_SIZE	(MAXPHYS / MDL_SEG_SIZE + 1) /* no hardware limit? */
252 
253 	if (bus_dmamap_create(esc->sc_dmat, MAXPHYS, MDL_SIZE, MDL_SEG_SIZE,
254 	    MDL_SEG_SIZE, BUS_DMA_NOWAIT, &esc->sc_xfermap)) {
255 		printf(": can't create DMA maps\n");
256 		return;
257 	}
258 
259 	/*
260 	 * Allocate and map memory for the MDL.
261 	 */
262 
263 	if ((error = bus_dmamem_alloc(esc->sc_dmat,
264 	    sizeof(u_int32_t) * MDL_SIZE, PAGE_SIZE, 0, &seg, 1, &rseg,
265 	    BUS_DMA_NOWAIT)) != 0) {
266 		printf(": unable to allocate memory for the MDL, error = %d\n",
267 		    error);
268 		return;
269 	}
270 	if ((error = bus_dmamem_map(esc->sc_dmat, &seg, rseg,
271 	    sizeof(u_int32_t) * MDL_SIZE , (caddr_t *)&esc->sc_mdladdr,
272 	    BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
273 		printf(": unable to map the MDL memory, error = %d\n", error);
274 		return;
275 	}
276 	if ((error = bus_dmamap_create(esc->sc_dmat,
277 	    sizeof(u_int32_t) * MDL_SIZE, 1, sizeof(u_int32_t) * MDL_SIZE,
278 	    0, BUS_DMA_NOWAIT, &esc->sc_mdldmap)) != 0) {
279 		printf(": unable to map_create for the MDL, error = %d\n",
280 		    error);
281 		return;
282 	}
283 	if ((error = bus_dmamap_load(esc->sc_dmat, esc->sc_mdldmap,
284 	     esc->sc_mdladdr, sizeof(u_int32_t) * MDL_SIZE,
285 	     NULL, BUS_DMA_NOWAIT)) != 0) {
286 		printf(": unable to load for the MDL, error = %d\n", error);
287 		return;
288 	}
289 
290 	/* map and establish interrupt */
291 	if (pci_intr_map(pa, &ih)) {
292 		printf(": couldn't map interrupt\n");
293 		return;
294 	}
295 
296 	intrstr = pci_intr_string(pa->pa_pc, ih);
297 	esc->sc_ih = pci_intr_establish(pa->pa_pc, ih, IPL_BIO,
298 	    ncr53c9x_intr, esc);
299 	if (esc->sc_ih == NULL) {
300 		printf(": couldn't establish interrupt");
301 		if (intrstr != NULL)
302 			printf(" at %s", intrstr);
303 		printf("\n");
304 		return;
305 	}
306 	if (intrstr != NULL)
307 		printf(": interrupting at %s\n", intrstr);
308 
309 	/* Do the common parts of attachment. */
310 	printf("%s", sc->sc_dev.dv_xname);
311 	sc->sc_adapter.adapt_minphys = minphys;
312 	sc->sc_adapter.adapt_request = ncr53c9x_scsipi_request;
313 	ncr53c9x_attach(sc);
314 
315 	/* Turn on target selection using the `DMA' method */
316 	sc->sc_features |= NCR_F_DMASELECT;
317 }
318 
319 /*
320  * Glue functions.
321  */
322 
323 u_char
324 pcscp_read_reg(sc, reg)
325 	struct ncr53c9x_softc *sc;
326 	int reg;
327 {
328 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
329 
330 	return PCSCP_READ_REG(esc, reg);
331 }
332 
333 void
334 pcscp_write_reg(sc, reg, v)
335 	struct ncr53c9x_softc *sc;
336 	int reg;
337 	u_char v;
338 {
339 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
340 
341 	PCSCP_WRITE_REG(esc, reg, v);
342 }
343 
344 int
345 pcscp_dma_isintr(sc)
346 	struct ncr53c9x_softc *sc;
347 {
348 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
349 
350 	return (PCSCP_READ_REG(esc, NCR_STAT) & NCRSTAT_INT) != 0;
351 }
352 
353 void
354 pcscp_dma_reset(sc)
355 	struct ncr53c9x_softc *sc;
356 {
357 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
358 
359 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE);
360 
361 	esc->sc_active = 0;
362 }
363 
364 int
365 pcscp_dma_intr(sc)
366 	struct ncr53c9x_softc *sc;
367 {
368 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
369 	int trans, resid, i;
370 	bus_dmamap_t dmap = esc->sc_xfermap;
371 	int datain = esc->sc_datain;
372 	u_int32_t dmastat;
373 	char *p = NULL;
374 
375 	dmastat = READ_DMAREG(esc, DMA_STAT);
376 
377 	if (dmastat & DMASTAT_ERR) {
378 		/* XXX not tested... */
379 		WRITE_DMAREG(esc, DMA_CMD,
380 		    DMACMD_ABORT | (datain ? DMACMD_DIR : 0));
381 
382 		printf("%s: error: DMA error detected; Aborting.\n",
383 		    sc->sc_dev.dv_xname);
384 		bus_dmamap_unload(esc->sc_dmat, dmap);
385 		return -1;
386 	}
387 
388 	if (dmastat & DMASTAT_ABT) {
389 		/* XXX What should be done? */
390 		printf("%s: dma_intr: DMA aborted.\n", sc->sc_dev.dv_xname);
391 		WRITE_DMAREG(esc, DMA_CMD,
392 		    DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
393 		esc->sc_active = 0;
394 		return 0;
395 	}
396 
397 #ifdef DIAGNOSTIC
398 	/* This is an "assertion" :) */
399 	if (esc->sc_active == 0)
400 		panic("pcscp dmaintr: DMA wasn't active");
401 #endif
402 
403 	/* DMA has stopped */
404 
405 	esc->sc_active = 0;
406 
407 	if (esc->sc_dmasize == 0) {
408 		/* A "Transfer Pad" operation completed */
409 		NCR_DMA(("dmaintr: discarded %d bytes (tcl=%d, tcm=%d)\n",
410 		    PCSCP_READ_REG(esc, NCR_TCL) |
411 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8),
412 		    PCSCP_READ_REG(esc, NCR_TCL),
413 		    PCSCP_READ_REG(esc, NCR_TCM)));
414 		return 0;
415 	}
416 
417 	resid = 0;
418 	/*
419 	 * If a transfer onto the SCSI bus gets interrupted by the device
420 	 * (e.g. for a SAVEPOINTER message), the data in the FIFO counts
421 	 * as residual since the ESP counter registers get decremented as
422 	 * bytes are clocked into the FIFO.
423 	 */
424 	if (!datain &&
425 	    (resid = (PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
426 		NCR_DMA(("pcscp_dma_intr: empty esp FIFO of %d ", resid));
427 	}
428 
429 	if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
430 		/*
431 		 * `Terminal count' is off, so read the residue
432 		 * out of the ESP counter registers.
433 		 */
434 		if (datain) {
435 			resid = PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
436 			while (resid > 1)
437 				resid =
438 				    PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
439 			WRITE_DMAREG(esc, DMA_CMD, DMACMD_BLAST | DMACMD_MDL |
440 			    (datain ? DMACMD_DIR : 0));
441 
442 			for (i = 0; i < 0x8000; i++) /* XXX 0x8000 ? */
443 				if (READ_DMAREG(esc, DMA_STAT) & DMASTAT_BCMP)
444 					break;
445 
446 			/* See the below comments... */
447 			if (resid)
448 				p = *esc->sc_dmaaddr;
449 		}
450 
451 		resid += PCSCP_READ_REG(esc, NCR_TCL) |
452 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8) |
453 		    (PCSCP_READ_REG(esc, NCR_TCH) << 16);
454 	} else {
455 		while ((dmastat & DMASTAT_DONE) == 0)
456 			dmastat = READ_DMAREG(esc, DMA_STAT);
457 	}
458 
459 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
460 
461 	/* sync MDL */
462 	bus_dmamap_sync(esc->sc_dmat, esc->sc_mdldmap,
463 	    0, sizeof(u_int32_t) * dmap->dm_nsegs, BUS_DMASYNC_POSTWRITE);
464 	/* sync transfer buffer */
465 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
466 	    datain ? BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
467 	bus_dmamap_unload(esc->sc_dmat, dmap);
468 
469 	trans = esc->sc_dmasize - resid;
470 
471 	/*
472 	 * From the technical manual notes:
473 	 *
474 	 * `In some odd byte conditions, one residual byte will be left
475 	 *  in the SCSI FIFO, and the FIFO flags will never count to 0.
476 	 *  When this happens, the residual byte should be retrieved
477 	 *  via PIO following completion of the BLAST operation.'
478 	 */
479 
480 	if (p) {
481 		p += trans;
482 		*p = PCSCP_READ_REG(esc, NCR_FIFO);
483 		trans++;
484 	}
485 
486 	if (trans < 0) {			/* transferred < 0 ? */
487 #if 0
488 		/*
489 		 * This situation can happen in perfectly normal operation
490 		 * if the ESP is reselected while using DMA to select
491 		 * another target.  As such, don't print the warning.
492 		 */
493 		printf("%s: xfer (%d) > req (%d)\n",
494 		    sc->sc_dev.dv_xname, trans, esc->sc_dmasize);
495 #endif
496 		trans = esc->sc_dmasize;
497 	}
498 
499 	NCR_DMA(("dmaintr: tcl=%d, tcm=%d, tch=%d; trans=%d, resid=%d\n",
500 	    PCSCP_READ_REG(esc, NCR_TCL),
501 	    PCSCP_READ_REG(esc, NCR_TCM),
502 	    PCSCP_READ_REG(esc, NCR_TCH),
503 	    trans, resid));
504 
505 	*esc->sc_dmalen -= trans;
506 	*esc->sc_dmaaddr += trans;
507 
508 	return 0;
509 }
510 
511 int
512 pcscp_dma_setup(sc, addr, len, datain, dmasize)
513 	struct ncr53c9x_softc *sc;
514 	caddr_t *addr;
515 	size_t *len;
516 	int datain;
517 	size_t *dmasize;
518 {
519 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
520 	bus_dmamap_t dmap = esc->sc_xfermap;
521 	u_int32_t *mdl;
522 	int error, nseg, seg;
523 	bus_addr_t s_offset, s_addr;
524 
525 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
526 
527 	esc->sc_dmaaddr = addr;
528 	esc->sc_dmalen = len;
529 	esc->sc_dmasize = *dmasize;
530 	esc->sc_datain = datain;
531 
532 #ifdef DIAGNOSTIC
533 	if ((*dmasize / MDL_SEG_SIZE) > MDL_SIZE)
534 		panic("pcscp: transfer size too large");
535 #endif
536 
537 	/*
538 	 * No need to set up DMA in `Transfer Pad' operation.
539 	 * (case of *dmasize == 0)
540 	 */
541 	if (*dmasize == 0)
542 		return 0;
543 
544 	error = bus_dmamap_load(esc->sc_dmat, dmap, *esc->sc_dmaaddr,
545 	    *esc->sc_dmalen, NULL,
546 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_NOSLEEP) ?
547 	    BUS_DMA_NOWAIT : BUS_DMA_WAITOK) | BUS_DMA_STREAMING |
548 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_DATA_IN) ?
549 	     BUS_DMA_READ : BUS_DMA_WRITE));
550 	if (error) {
551 		printf("%s: unable to load dmamap, error = %d\n",
552 		    sc->sc_dev.dv_xname, error);
553 		return error;
554 	}
555 
556 	/* set transfer length */
557 	WRITE_DMAREG(esc, DMA_STC, *dmasize);
558 
559 	/* set up MDL */
560 	mdl = esc->sc_mdladdr;
561 	nseg = dmap->dm_nsegs;
562 
563 	/* the first segment is possibly not aligned with 4k MDL boundary */
564 	s_addr = dmap->dm_segs[0].ds_addr;
565 	s_offset = s_addr & MDL_SEG_OFFSET;
566 	s_addr -= s_offset;
567 
568 	/* set the first MDL and offset */
569 	WRITE_DMAREG(esc, DMA_SPA, s_offset);
570 	*mdl++ = htole32(s_addr);
571 
572 	/* the rest dmamap segments are aligned with 4k boundary */
573 	for (seg = 1; seg < nseg; seg++)
574 		*mdl++ = htole32(dmap->dm_segs[seg].ds_addr);
575 
576 	return 0;
577 }
578 
579 void
580 pcscp_dma_go(sc)
581 	struct ncr53c9x_softc *sc;
582 {
583 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
584 	bus_dmamap_t dmap = esc->sc_xfermap, mdldmap = esc->sc_mdldmap;
585 	int datain = esc->sc_datain;
586 
587 	/* No DMA transfer in Transfer Pad operation */
588 	if (esc->sc_dmasize == 0)
589 		return;
590 
591 	/* sync transfer buffer */
592 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
593 	    datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
594 
595 	/* sync MDL */
596 	bus_dmamap_sync(esc->sc_dmat, mdldmap,
597 	    0, sizeof(u_int32_t) * dmap->dm_nsegs, BUS_DMASYNC_PREWRITE);
598 
599 	/* set Starting MDL Address */
600 	WRITE_DMAREG(esc, DMA_SMDLA, mdldmap->dm_segs[0].ds_addr);
601 
602 	/* set DMA command register bits */
603 	/* XXX DMA Transfer Interrupt Enable bit is broken? */
604 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | DMACMD_MDL |
605 	    /* DMACMD_INTE | */
606 	    (datain ? DMACMD_DIR : 0));
607 
608 	/* issue DMA start command */
609 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_START | DMACMD_MDL |
610 	    /* DMACMD_INTE | */
611 	    (datain ? DMACMD_DIR : 0));
612 
613 	esc->sc_active = 1;
614 }
615 
616 void
617 pcscp_dma_stop(sc)
618 	struct ncr53c9x_softc *sc;
619 {
620 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
621 
622 	/* DMA stop */
623 	/* XXX What should we do here ? */
624 	WRITE_DMAREG(esc, DMA_CMD,
625 	    DMACMD_ABORT | (esc->sc_datain ? DMACMD_DIR : 0));
626 
627 	esc->sc_active = 0;
628 }
629 
630 int
631 pcscp_dma_isactive(sc)
632 	struct ncr53c9x_softc *sc;
633 {
634 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
635 
636 	/* XXX should check esc->sc_active? */
637 	if ((READ_DMAREG(esc, DMA_CMD) & DMACMD_CMD) != DMACMD_IDLE)
638 		return 1;
639 	return 0;
640 }
641