xref: /netbsd-src/sys/dev/pci/pcscp.c (revision 37b34d511dea595d3ba03a661cf3b775038ea5f8)
1 /*	$NetBSD: pcscp.c,v 1.20 2002/10/02 16:51:53 thorpej 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/products/npd/techdocs/techdocs.html
46  */
47 
48 #include <sys/cdefs.h>
49 __KERNEL_RCSID(0, "$NetBSD: pcscp.c,v 1.20 2002/10/02 16:51:53 thorpej 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 #include <machine/endian.h>
59 
60 #include <uvm/uvm_extern.h>
61 
62 #include <dev/scsipi/scsipi_all.h>
63 #include <dev/scsipi/scsi_all.h>
64 #include <dev/scsipi/scsiconf.h>
65 
66 #include <dev/pci/pcireg.h>
67 #include <dev/pci/pcivar.h>
68 #include <dev/pci/pcidevs.h>
69 
70 #include <dev/ic/ncr53c9xreg.h>
71 #include <dev/ic/ncr53c9xvar.h>
72 
73 #include <dev/pci/pcscpreg.h>
74 
75 #define IO_MAP_REG	0x10
76 #define MEM_MAP_REG	0x14
77 
78 struct pcscp_softc {
79 	struct ncr53c9x_softc sc_ncr53c9x;	/* glue to MI code */
80 
81 	bus_space_tag_t sc_st;		/* bus space tag */
82 	bus_space_handle_t sc_sh;	/* bus space handle */
83 	void *sc_ih;			/* interrupt cookie */
84 
85 	bus_dma_tag_t sc_dmat;		/* DMA tag */
86 
87 	bus_dmamap_t sc_xfermap;	/* DMA map for transfers */
88 
89 	u_int32_t *sc_mdladdr;		/* MDL array */
90 	bus_dmamap_t sc_mdldmap;	/* MDL DMA map */
91 
92 	int	sc_active;		/* DMA state */
93 	int	sc_datain;		/* DMA Data Direction */
94 	size_t	sc_dmasize;		/* DMA size */
95 	char	**sc_dmaaddr;		/* DMA address */
96 	size_t	*sc_dmalen;		/* DMA length */
97 };
98 
99 #define	READ_DMAREG(sc, reg) \
100 	bus_space_read_4((sc)->sc_st, (sc)->sc_sh, (reg))
101 #define	WRITE_DMAREG(sc, reg, var) \
102 	bus_space_write_4((sc)->sc_st, (sc)->sc_sh, (reg), (var))
103 
104 /* don't have to use MI defines in MD code... */
105 #undef	NCR_READ_REG
106 #define	NCR_READ_REG(sc, reg)		pcscp_read_reg((sc), (reg))
107 #undef	NCR_WRITE_REG
108 #define	NCR_WRITE_REG(sc, reg, val)	pcscp_write_reg((sc), (reg), (val))
109 
110 int	pcscp_match __P((struct device *, struct cfdata *, void *));
111 void	pcscp_attach __P((struct device *, struct device *, void *));
112 
113 CFATTACH_DECL(pcscp, sizeof(struct pcscp_softc),
114     pcscp_match, pcscp_attach, NULL, NULL);
115 
116 /*
117  * Functions and the switch for the MI code.
118  */
119 
120 u_char	pcscp_read_reg __P((struct ncr53c9x_softc *, int));
121 void	pcscp_write_reg __P((struct ncr53c9x_softc *, int, u_char));
122 int	pcscp_dma_isintr __P((struct ncr53c9x_softc *));
123 void	pcscp_dma_reset __P((struct ncr53c9x_softc *));
124 int	pcscp_dma_intr __P((struct ncr53c9x_softc *));
125 int	pcscp_dma_setup __P((struct ncr53c9x_softc *, caddr_t *,
126 			       size_t *, int, size_t *));
127 void	pcscp_dma_go __P((struct ncr53c9x_softc *));
128 void	pcscp_dma_stop __P((struct ncr53c9x_softc *));
129 int	pcscp_dma_isactive __P((struct ncr53c9x_softc *));
130 
131 struct ncr53c9x_glue pcscp_glue = {
132 	pcscp_read_reg,
133 	pcscp_write_reg,
134 	pcscp_dma_isintr,
135 	pcscp_dma_reset,
136 	pcscp_dma_intr,
137 	pcscp_dma_setup,
138 	pcscp_dma_go,
139 	pcscp_dma_stop,
140 	pcscp_dma_isactive,
141 	NULL,			/* gl_clear_latched_intr */
142 };
143 
144 int
145 pcscp_match(parent, match, aux)
146 	struct device *parent;
147 	struct cfdata *match;
148 	void *aux;
149 {
150 	struct pci_attach_args *pa = aux;
151 	if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_AMD)
152 		return 0;
153 
154 	switch (PCI_PRODUCT(pa->pa_id)) {
155 	case PCI_PRODUCT_AMD_PCSCSI_PCI:
156 #if 0
157 	case PCI_PRODUCT_AMD_PCNETS_PCI:
158 #endif
159 		return 1;
160 	}
161 	return 0;
162 }
163 
164 /*
165  * Attach this instance, and then all the sub-devices
166  */
167 void
168 pcscp_attach(parent, self, aux)
169 	struct device *parent, *self;
170 	void *aux;
171 {
172 	struct pci_attach_args *pa = aux;
173 	struct pcscp_softc *esc = (void *)self;
174 	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
175 	bus_space_tag_t st, iot, memt;
176 	bus_space_handle_t sh, ioh, memh;
177 	int ioh_valid, memh_valid;
178 	pci_intr_handle_t ih;
179 	const char *intrstr;
180 	pcireg_t csr;
181 	bus_dma_segment_t seg;
182 	int error, rseg;
183 
184 	ioh_valid = (pci_mapreg_map(pa, IO_MAP_REG,
185 	    PCI_MAPREG_TYPE_IO, 0,
186 	    &iot, &ioh, NULL, NULL) == 0);
187 #if 0	/* XXX cannot use memory map? */
188 	memh_valid = (pci_mapreg_map(pa, MEM_MAP_REG,
189 	    PCI_MAPREG_TYPE_MEM | PCI_MAPREG_MEM_TYPE_32BIT, 0,
190 	    &memt, &memh, NULL, NULL) == 0);
191 #else
192 	memh_valid = 0;
193 #endif
194 
195 	if (memh_valid) {
196 		st = memt;
197 		sh = memh;
198 	} else if (ioh_valid) {
199 		st = iot;
200 		sh = ioh;
201 	} else {
202 		printf(": unable to map registers\n");
203 		return;
204 	}
205 	printf("\n");
206 
207 	sc->sc_glue = &pcscp_glue;
208 
209 	esc->sc_st = st;
210 	esc->sc_sh = sh;
211 	esc->sc_dmat = pa->pa_dmat;
212 
213 	csr = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG);
214 	pci_conf_write(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG,
215 	    csr | PCI_COMMAND_MASTER_ENABLE | PCI_COMMAND_IO_ENABLE);
216 
217 	/*
218 	 * XXX More of this should be in ncr53c9x_attach(), but
219 	 * XXX should we really poke around the chip that much in
220 	 * XXX the MI code?  Think about this more...
221 	 */
222 
223 	/*
224 	 * Set up static configuration info.
225 	 */
226 
227 	/*
228 	 * XXX should read configuration from EEPROM?
229 	 *
230 	 * MI ncr53c9x driver does not support configuration
231 	 * per each target device, though...
232 	 */
233 	sc->sc_id = 7;
234 	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
235 	sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_FE;
236 	sc->sc_cfg3 = NCRAMDCFG3_IDM | NCRAMDCFG3_FCLK;
237 	sc->sc_cfg4 = NCRAMDCFG4_GE12NS | NCRAMDCFG4_RADE;
238 	sc->sc_rev = NCR_VARIANT_AM53C974;
239 	sc->sc_features = NCR_F_FASTSCSI;
240 	sc->sc_cfg3_fscsi = NCRAMDCFG3_FSCSI;
241 	sc->sc_freq = 40; /* MHz */
242 
243 	/*
244 	 * XXX minsync and maxxfer _should_ be set up in MI code,
245 	 * XXX but it appears to have some dependency on what sort
246 	 * XXX of DMA we're hooked up to, etc.
247 	 */
248 
249 	/*
250 	 * This is the value used to start sync negotiations
251 	 * Note that the NCR register "SYNCTP" is programmed
252 	 * in "clocks per byte", and has a minimum value of 4.
253 	 * The SCSI period used in negotiation is one-fourth
254 	 * of the time (in nanoseconds) needed to transfer one byte.
255 	 * Since the chip's clock is given in MHz, we have the following
256 	 * formula: 4 * period = (1000 / freq) * 4
257 	 */
258 
259 	sc->sc_minsync = 1000 / sc->sc_freq;
260 
261 	/* Really no limit, but since we want to fit into the TCR... */
262 	sc->sc_maxxfer = 16 * 1024 * 1024;
263 
264 	/* map and establish interrupt */
265 	if (pci_intr_map(pa, &ih)) {
266 		printf("%s: couldn't map interrupt\n", sc->sc_dev.dv_xname);
267 		return;
268 	}
269 
270 	intrstr = pci_intr_string(pa->pa_pc, ih);
271 	esc->sc_ih = pci_intr_establish(pa->pa_pc, ih, IPL_BIO,
272 	    ncr53c9x_intr, esc);
273 	if (esc->sc_ih == NULL) {
274 		printf("%s: couldn't establish interrupt", sc->sc_dev.dv_xname);
275 		if (intrstr != NULL)
276 			printf(" at %s", intrstr);
277 		printf("\n");
278 		return;
279 	}
280 	if (intrstr != NULL)
281 		printf("%s: interrupting at %s\n", sc->sc_dev.dv_xname,
282 		    intrstr);
283 
284 	/*
285 	 * Create the DMA maps for the data transfers.
286          */
287 
288 #define MDL_SEG_SIZE	0x1000 /* 4kbyte per segment */
289 #define MDL_SEG_OFFSET	0x0FFF
290 #define MDL_SIZE	(MAXPHYS / MDL_SEG_SIZE + 1) /* no hardware limit? */
291 
292 	if (bus_dmamap_create(esc->sc_dmat, MAXPHYS, MDL_SIZE, MAXPHYS, 0,
293 	    BUS_DMA_NOWAIT, &esc->sc_xfermap)) {
294 		printf("%s: can't create dma maps\n", sc->sc_dev.dv_xname);
295 		return;
296 	}
297 
298 	/*
299 	 * Allocate and map memory for the MDL.
300 	 */
301 
302 	if ((error = bus_dmamem_alloc(esc->sc_dmat,
303 	    sizeof(u_int32_t) * MDL_SIZE, PAGE_SIZE, 0, &seg, 1, &rseg,
304 	    BUS_DMA_NOWAIT)) != 0) {
305 		printf("%s: unable to allocate memory for the MDL, "
306 		    "error = %d\n", sc->sc_dev.dv_xname, error);
307 		return;
308 	}
309 	if ((error = bus_dmamem_map(esc->sc_dmat, &seg, rseg,
310 	    sizeof(u_int32_t) * MDL_SIZE , (caddr_t *)&esc->sc_mdladdr,
311 	    BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
312 		printf("%s: unable to map the MDL memory, error = %d\n",
313 		    sc->sc_dev.dv_xname, error);
314 		return;
315 	}
316 	if ((error = bus_dmamap_create(esc->sc_dmat,
317 	    sizeof(u_int32_t) * MDL_SIZE, 1, sizeof(u_int32_t) * MDL_SIZE,
318 	    0, BUS_DMA_NOWAIT, &esc->sc_mdldmap)) != 0) {
319 		printf("%s: unable to map_create for the MDL, error = %d\n",
320 		    sc->sc_dev.dv_xname, error);
321 		return;
322 	}
323 	if ((error = bus_dmamap_load(esc->sc_dmat, esc->sc_mdldmap,
324 	     esc->sc_mdladdr, sizeof(u_int32_t) * MDL_SIZE,
325 	     NULL, BUS_DMA_NOWAIT)) != 0) {
326 		printf("%s: unable to load for the MDL, error = %d\n",
327 		    sc->sc_dev.dv_xname, error);
328 		return;
329 	}
330 
331 	/* Do the common parts of attachment. */
332 	printf("%s", sc->sc_dev.dv_xname);
333 
334 	sc->sc_adapter.adapt_minphys = minphys;
335 	sc->sc_adapter.adapt_request = ncr53c9x_scsipi_request;
336 	ncr53c9x_attach(sc);
337 
338 	/* Turn on target selection using the `dma' method */
339 	sc->sc_features |= NCR_F_DMASELECT;
340 }
341 
342 /*
343  * Glue functions.
344  */
345 
346 u_char
347 pcscp_read_reg(sc, reg)
348 	struct ncr53c9x_softc *sc;
349 	int reg;
350 {
351 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
352 
353 	return bus_space_read_1(esc->sc_st, esc->sc_sh, reg << 2);
354 }
355 
356 void
357 pcscp_write_reg(sc, reg, v)
358 	struct ncr53c9x_softc *sc;
359 	int reg;
360 	u_char v;
361 {
362 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
363 
364 	bus_space_write_1(esc->sc_st, esc->sc_sh, reg << 2, v);
365 }
366 
367 int
368 pcscp_dma_isintr(sc)
369 	struct ncr53c9x_softc *sc;
370 {
371 
372 	return NCR_READ_REG(sc, NCR_STAT) & NCRSTAT_INT;
373 }
374 
375 void
376 pcscp_dma_reset(sc)
377 	struct ncr53c9x_softc *sc;
378 {
379 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
380 
381 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE);
382 
383 	esc->sc_active = 0;
384 }
385 
386 int
387 pcscp_dma_intr(sc)
388 	struct ncr53c9x_softc *sc;
389 {
390 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
391 	int trans, resid, i;
392 	bus_dmamap_t dmap = esc->sc_xfermap;
393 	int datain = esc->sc_datain;
394 	u_int32_t dmastat;
395 	char *p = NULL;
396 
397 	dmastat = READ_DMAREG(esc, DMA_STAT);
398 
399 	if (dmastat & DMASTAT_ERR) {
400 		/* XXX not tested... */
401 		WRITE_DMAREG(esc, DMA_CMD,
402 		    DMACMD_ABORT | (datain ? DMACMD_DIR : 0));
403 
404 		printf("%s: error: DMA error detected; Aborting.\n",
405 		    sc->sc_dev.dv_xname);
406 		bus_dmamap_unload(esc->sc_dmat, dmap);
407 		return -1;
408 	}
409 
410 	if (dmastat & DMASTAT_ABT) {
411 		/* XXX What should be done? */
412 		printf("%s: dma_intr: DMA aborted.\n", sc->sc_dev.dv_xname);
413 		WRITE_DMAREG(esc, DMA_CMD,
414 		    DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
415 		esc->sc_active = 0;
416 		return 0;
417 	}
418 
419 	/* This is an "assertion" :) */
420 	if (esc->sc_active == 0)
421 		panic("pcscp dmaintr: DMA wasn't active");
422 
423 	/* DMA has stopped */
424 
425 	esc->sc_active = 0;
426 
427 	if (esc->sc_dmasize == 0) {
428 		/* A "Transfer Pad" operation completed */
429 		NCR_DMA(("dmaintr: discarded %d bytes (tcl=%d, tcm=%d)\n",
430 		    NCR_READ_REG(sc, NCR_TCL) |
431 		    (NCR_READ_REG(sc, NCR_TCM) << 8),
432 		    NCR_READ_REG(sc, NCR_TCL),
433 		    NCR_READ_REG(sc, NCR_TCM)));
434 		return 0;
435 	}
436 
437 	resid = 0;
438 	/*
439 	 * If a transfer onto the SCSI bus gets interrupted by the device
440 	 * (e.g. for a SAVEPOINTER message), the data in the FIFO counts
441 	 * as residual since the ESP counter registers get decremented as
442 	 * bytes are clocked into the FIFO.
443 	 */
444 	if (!datain &&
445 	    (resid = (NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
446 		NCR_DMA(("pcscp_dma_intr: empty esp FIFO of %d ", resid));
447 	}
448 
449 	if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
450 		/*
451 		 * `Terminal count' is off, so read the residue
452 		 * out of the ESP counter registers.
453 		 */
454 		if (datain) {
455 			resid = NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF;
456 			while (resid > 1)
457 				resid =
458 				    NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF;
459 			WRITE_DMAREG(esc, DMA_CMD, DMACMD_BLAST | DMACMD_MDL |
460 			    (datain ? DMACMD_DIR : 0));
461 
462 			for (i = 0; i < 0x8000; i++) /* XXX 0x8000 ? */
463 				if (READ_DMAREG(esc, DMA_STAT) & DMASTAT_BCMP)
464 					break;
465 
466 			/* See the below comments... */
467 			if (resid)
468 				p = *esc->sc_dmaaddr;
469 		}
470 
471 		resid += (NCR_READ_REG(sc, NCR_TCL) |
472 		    (NCR_READ_REG(sc, NCR_TCM) << 8) |
473 		    ((sc->sc_cfg2 & NCRCFG2_FE)
474 		    ? (NCR_READ_REG(sc, NCR_TCH) << 16) : 0));
475 
476 		if (resid == 0 && esc->sc_dmasize == 65536 &&
477 		    (sc->sc_cfg2 & NCRCFG2_FE) == 0)
478 			/* A transfer of 64K is encoded as `TCL=TCM=0' */
479 			resid = 65536;
480 	} else {
481 		while((dmastat & DMASTAT_DONE) == 0)
482 			dmastat = READ_DMAREG(esc, DMA_STAT);
483 	}
484 
485 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
486 
487 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
488 	    datain ? BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
489 	bus_dmamap_unload(esc->sc_dmat, dmap);
490 
491 	trans = esc->sc_dmasize - resid;
492 
493 	/*
494 	 * From the technical manual notes:
495 	 *
496 	 * `In some odd byte conditions, one residual byte will be left
497 	 *  in the SCSI FIFO, and the FIFO flags will never count to 0.
498 	 *  When this happens, the residual byte should be retrieved
499 	 *  via PIO following completion of the BLAST operation.'
500 	 */
501 
502 	if (p) {
503 		p += trans;
504 		*p = NCR_READ_REG(sc, NCR_FIFO);
505 		trans++;
506 	}
507 
508 	if (trans < 0) {			/* transferred < 0 ? */
509 #if 0
510 		/*
511 		 * This situation can happen in perfectly normal operation
512 		 * if the ESP is reselected while using DMA to select
513 		 * another target.  As such, don't print the warning.
514 		 */
515 		printf("%s: xfer (%d) > req (%d)\n",
516 		    sc->sc_dev.dv_xname, trans, esc->sc_dmasize);
517 #endif
518 		trans = esc->sc_dmasize;
519 	}
520 
521 	NCR_DMA(("dmaintr: tcl=%d, tcm=%d, tch=%d; trans=%d, resid=%d\n",
522 	    NCR_READ_REG(sc, NCR_TCL),
523 	    NCR_READ_REG(sc, NCR_TCM),
524 	    (sc->sc_cfg2 & NCRCFG2_FE) ? NCR_READ_REG(sc, NCR_TCH) : 0,
525 	    trans, resid));
526 
527 	*esc->sc_dmalen -= trans;
528 	*esc->sc_dmaaddr += trans;
529 
530 	return 0;
531 }
532 
533 int
534 pcscp_dma_setup(sc, addr, len, datain, dmasize)
535 	struct ncr53c9x_softc *sc;
536 	caddr_t *addr;
537 	size_t *len;
538 	int datain;
539 	size_t *dmasize;
540 {
541 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
542 	bus_dmamap_t dmap = esc->sc_xfermap;
543 	u_int32_t *mdl;
544 	int error, nseg, seg;
545 	bus_addr_t s_offset, s_addr;
546 	long rest, count;
547 
548 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
549 
550 	esc->sc_dmaaddr = addr;
551 	esc->sc_dmalen = len;
552 	esc->sc_dmasize = *dmasize;
553 	esc->sc_datain = datain;
554 
555 #ifdef DIAGNOSTIC
556 	if ((*dmasize / MDL_SEG_SIZE) > MDL_SIZE)
557 		panic("pcscp: transfer size too large");
558 #endif
559 
560 	/*
561 	 * No need to set up DMA in `Transfer Pad' operation.
562 	 * (case of *dmasize == 0)
563 	 */
564 	if (*dmasize == 0)
565 		return 0;
566 
567 	error = bus_dmamap_load(esc->sc_dmat, dmap, *esc->sc_dmaaddr,
568 	    *esc->sc_dmalen, NULL,
569 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_NOSLEEP) ?
570 	    BUS_DMA_NOWAIT : BUS_DMA_WAITOK) | BUS_DMA_STREAMING |
571 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_DATA_IN) ?
572 	     BUS_DMA_READ : BUS_DMA_WRITE));
573 	if (error) {
574 		printf("%s: unable to load dmamap, error = %d\n",
575 		    sc->sc_dev.dv_xname, error);
576 		return error;
577 	}
578 
579 	/* set transfer length */
580 	WRITE_DMAREG(esc, DMA_STC, *dmasize);
581 
582 	/* set up MDL */
583 	mdl = esc->sc_mdladdr;
584 	nseg = dmap->dm_nsegs;
585 
586 	/* the first segment is possibly not aligned with 4k MDL boundary */
587 	count = dmap->dm_segs[0].ds_len;
588 	s_addr = dmap->dm_segs[0].ds_addr;
589 	s_offset = s_addr & MDL_SEG_OFFSET;
590 	s_addr -= s_offset;
591 	rest = MDL_SEG_SIZE - s_offset;
592 
593 	/* set the first MDL and offset */
594 	WRITE_DMAREG(esc, DMA_SPA, s_offset);
595 	*mdl++ = htole32(s_addr);
596 	count -= rest;
597 
598 	/* rests of the first dmamap segment */
599 	while (count > 0) {
600 		s_addr += MDL_SEG_SIZE;
601 		*mdl++ = htole32(s_addr);
602 		count -= MDL_SEG_SIZE;
603 	}
604 
605 	/* the rest dmamap segments are aligned with 4k boundary */
606 	for (seg = 1; seg < nseg; seg++) {
607 		count = dmap->dm_segs[seg].ds_len;
608 		s_addr = dmap->dm_segs[seg].ds_addr;
609 
610 		/* first 4kbyte of each dmamap segment */
611 		*mdl++ = htole32(s_addr);
612 		count -= MDL_SEG_SIZE;
613 
614 		/* trailing contiguous 4k frames of each dmamap segments */
615 		while (count > 0) {
616 			s_addr += MDL_SEG_SIZE;
617 			*mdl++ = htole32(s_addr);
618 			count -= MDL_SEG_SIZE;
619 		}
620 	}
621 
622 	return 0;
623 }
624 
625 void
626 pcscp_dma_go(sc)
627 	struct ncr53c9x_softc *sc;
628 {
629 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
630 	bus_dmamap_t dmap = esc->sc_xfermap, mdldmap = esc->sc_mdldmap;
631 	int datain = esc->sc_datain;
632 
633 	/* No DMA transfer in Transfer Pad operation */
634 	if (esc->sc_dmasize == 0)
635 		return;
636 
637 	/* sync transfer buffer */
638 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
639 	    datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
640 
641 	/* sync MDL */
642 	bus_dmamap_sync(esc->sc_dmat, mdldmap, 0, mdldmap->dm_mapsize,
643 	    BUS_DMASYNC_PREWRITE);
644 
645 	/* set Starting MDL Address */
646 	WRITE_DMAREG(esc, DMA_SMDLA, mdldmap->dm_segs[0].ds_addr);
647 
648 	/* set DMA command register bits */
649 	/* XXX DMA Transfer Interrupt Enable bit is broken? */
650 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | DMACMD_MDL |
651 	    /* DMACMD_INTE | */
652 	    (datain ? DMACMD_DIR : 0));
653 
654 	/* issue DMA start command */
655 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_START | DMACMD_MDL |
656 	    /* DMACMD_INTE | */
657 	    (datain ? DMACMD_DIR : 0));
658 
659 	esc->sc_active = 1;
660 }
661 
662 void
663 pcscp_dma_stop(sc)
664 	struct ncr53c9x_softc *sc;
665 {
666 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
667 
668 	/* dma stop */
669 	/* XXX What should we do here ? */
670 	WRITE_DMAREG(esc, DMA_CMD,
671 	    DMACMD_ABORT | (esc->sc_datain ? DMACMD_DIR : 0));
672 
673 	esc->sc_active = 0;
674 }
675 
676 int
677 pcscp_dma_isactive(sc)
678 	struct ncr53c9x_softc *sc;
679 {
680 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
681 
682 	/* XXX should check esc->sc_active? */
683 	if ((READ_DMAREG(esc, DMA_CMD) & DMACMD_CMD) != DMACMD_IDLE)
684 		return 1;
685 	return 0;
686 }
687