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pcscp.c revision 1.45.8.1
      1 /*	$NetBSD: pcscp.c,v 1.45.8.1 2012/04/17 00:07:57 yamt 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  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * pcscp.c: device dependent code for AMD Am53c974 (PCscsi-PCI)
     35  * written by Izumi Tsutsui <tsutsui (at) NetBSD.org>
     36  *
     37  * Technical manual available at
     38  * http://www.amd.com/files/connectivitysolutions/networking/archivednetworking/19113.pdf
     39  */
     40 
     41 #include <sys/cdefs.h>
     42 __KERNEL_RCSID(0, "$NetBSD: pcscp.c,v 1.45.8.1 2012/04/17 00:07:57 yamt Exp $");
     43 
     44 #include <sys/param.h>
     45 #include <sys/systm.h>
     46 #include <sys/device.h>
     47 #include <sys/buf.h>
     48 
     49 #include <sys/bus.h>
     50 #include <sys/intr.h>
     51 
     52 #include <dev/scsipi/scsipi_all.h>
     53 #include <dev/scsipi/scsi_all.h>
     54 #include <dev/scsipi/scsiconf.h>
     55 
     56 #include <dev/pci/pcireg.h>
     57 #include <dev/pci/pcivar.h>
     58 #include <dev/pci/pcidevs.h>
     59 
     60 #include <dev/ic/ncr53c9xreg.h>
     61 #include <dev/ic/ncr53c9xvar.h>
     62 
     63 #include <dev/pci/pcscpreg.h>
     64 
     65 #define IO_MAP_REG	0x10
     66 
     67 struct pcscp_softc {
     68 	struct ncr53c9x_softc sc_ncr53c9x;	/* glue to MI code */
     69 
     70 	bus_space_tag_t sc_st;		/* bus space tag */
     71 	bus_space_handle_t sc_sh;	/* bus space handle */
     72 	void *sc_ih;			/* interrupt cookie */
     73 
     74 	bus_dma_tag_t sc_dmat;		/* DMA tag */
     75 
     76 	bus_dmamap_t sc_xfermap;	/* DMA map for transfers */
     77 
     78 	uint32_t *sc_mdladdr;		/* MDL array */
     79 	bus_dmamap_t sc_mdldmap;	/* MDL DMA map */
     80 
     81 	int	sc_active;		/* DMA state */
     82 	int	sc_datain;		/* DMA Data Direction */
     83 	size_t	sc_dmasize;		/* DMA size */
     84 	uint8_t	**sc_dmaaddr;		/* DMA address */
     85 	size_t	*sc_dmalen;		/* DMA length */
     86 };
     87 
     88 #define	READ_DMAREG(sc, reg) \
     89 	bus_space_read_4((sc)->sc_st, (sc)->sc_sh, (reg))
     90 #define	WRITE_DMAREG(sc, reg, var) \
     91 	bus_space_write_4((sc)->sc_st, (sc)->sc_sh, (reg), (var))
     92 
     93 #define	PCSCP_READ_REG(sc, reg)	\
     94 	bus_space_read_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2)
     95 #define	PCSCP_WRITE_REG(sc, reg, val)	\
     96 	bus_space_write_1((sc)->sc_st, (sc)->sc_sh, (reg) << 2, (val))
     97 
     98 
     99 static int pcscp_match(device_t, cfdata_t, void *);
    100 static void pcscp_attach(device_t, device_t, void *);
    101 
    102 CFATTACH_DECL_NEW(pcscp, sizeof(struct pcscp_softc),
    103     pcscp_match, pcscp_attach, NULL, NULL);
    104 
    105 /*
    106  * Functions and the switch for the MI code.
    107  */
    108 
    109 static uint8_t	pcscp_read_reg(struct ncr53c9x_softc *, int);
    110 static void	pcscp_write_reg(struct ncr53c9x_softc *, int, uint8_t);
    111 static int	pcscp_dma_isintr(struct ncr53c9x_softc *);
    112 static void	pcscp_dma_reset(struct ncr53c9x_softc *);
    113 static int	pcscp_dma_intr(struct ncr53c9x_softc *);
    114 static int	pcscp_dma_setup(struct ncr53c9x_softc *, uint8_t **, size_t *,
    115 		    int, size_t *);
    116 static void	pcscp_dma_go(struct ncr53c9x_softc *);
    117 static void	pcscp_dma_stop(struct ncr53c9x_softc *);
    118 static int	pcscp_dma_isactive(struct ncr53c9x_softc *);
    119 
    120 static struct ncr53c9x_glue pcscp_glue = {
    121 	pcscp_read_reg,
    122 	pcscp_write_reg,
    123 	pcscp_dma_isintr,
    124 	pcscp_dma_reset,
    125 	pcscp_dma_intr,
    126 	pcscp_dma_setup,
    127 	pcscp_dma_go,
    128 	pcscp_dma_stop,
    129 	pcscp_dma_isactive,
    130 	NULL,			/* gl_clear_latched_intr */
    131 };
    132 
    133 static int
    134 pcscp_match(device_t parent, cfdata_t cf, void *aux)
    135 {
    136 	struct pci_attach_args *pa = aux;
    137 
    138 	if (PCI_VENDOR(pa->pa_id) != PCI_VENDOR_AMD)
    139 		return 0;
    140 
    141 	switch (PCI_PRODUCT(pa->pa_id)) {
    142 	case PCI_PRODUCT_AMD_PCSCSI_PCI:
    143 		return 1;
    144 	}
    145 	return 0;
    146 }
    147 
    148 /*
    149  * Attach this instance, and then all the sub-devices
    150  */
    151 static void
    152 pcscp_attach(device_t parent, device_t self, void *aux)
    153 {
    154 	struct pcscp_softc *esc = device_private(self);
    155 	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
    156 	struct pci_attach_args *pa = aux;
    157 	bus_space_tag_t iot;
    158 	bus_space_handle_t ioh;
    159 	pci_intr_handle_t ih;
    160 	const char *intrstr;
    161 	pcireg_t csr;
    162 	bus_dma_segment_t seg;
    163 	int error, rseg;
    164 
    165 	sc->sc_dev = self;
    166 	pci_aprint_devinfo(pa, NULL);
    167 	aprint_normal("%s", device_xname(sc->sc_dev));
    168 
    169 	if (pci_mapreg_map(pa, IO_MAP_REG, PCI_MAPREG_TYPE_IO, 0,
    170 	    &iot, &ioh, NULL, NULL)) {
    171 		aprint_error(": unable to map registers\n");
    172 		return;
    173 	}
    174 
    175 	sc->sc_glue = &pcscp_glue;
    176 
    177 	esc->sc_st = iot;
    178 	esc->sc_sh = ioh;
    179 	esc->sc_dmat = pa->pa_dmat;
    180 
    181 	csr = pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG);
    182 	pci_conf_write(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG,
    183 	    csr | PCI_COMMAND_MASTER_ENABLE | PCI_COMMAND_IO_ENABLE);
    184 
    185 	/*
    186 	 * XXX More of this should be in ncr53c9x_attach(), but
    187 	 * XXX should we really poke around the chip that much in
    188 	 * XXX the MI code?  Think about this more...
    189 	 */
    190 
    191 	/*
    192 	 * Set up static configuration info.
    193 	 */
    194 
    195 	/*
    196 	 * XXX should read configuration from EEPROM?
    197 	 *
    198 	 * MI ncr53c9x driver does not support configuration
    199 	 * per each target device, though...
    200 	 */
    201 	sc->sc_id = 7;
    202 	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
    203 	sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_FE;
    204 	sc->sc_cfg3 = NCRAMDCFG3_IDM | NCRAMDCFG3_FCLK;
    205 	sc->sc_cfg4 = NCRAMDCFG4_GE12NS | NCRAMDCFG4_RADE;
    206 	sc->sc_rev = NCR_VARIANT_AM53C974;
    207 	sc->sc_features = NCR_F_FASTSCSI;
    208 	sc->sc_cfg3_fscsi = NCRAMDCFG3_FSCSI;
    209 	sc->sc_freq = 40; /* MHz */
    210 
    211 	/*
    212 	 * XXX minsync and maxxfer _should_ be set up in MI code,
    213 	 * XXX but it appears to have some dependency on what sort
    214 	 * XXX of DMA we're hooked up to, etc.
    215 	 */
    216 
    217 	/*
    218 	 * This is the value used to start sync negotiations
    219 	 * Note that the NCR register "SYNCTP" is programmed
    220 	 * in "clocks per byte", and has a minimum value of 4.
    221 	 * The SCSI period used in negotiation is one-fourth
    222 	 * of the time (in nanoseconds) needed to transfer one byte.
    223 	 * Since the chip's clock is given in MHz, we have the following
    224 	 * formula: 4 * period = (1000 / freq) * 4
    225 	 */
    226 
    227 	sc->sc_minsync = 1000 / sc->sc_freq;
    228 
    229 	/* Really no limit, but since we want to fit into the TCR... */
    230 	sc->sc_maxxfer = 16 * 1024 * 1024;
    231 
    232 	/*
    233 	 * Create the DMA maps for the data transfers.
    234 	 */
    235 
    236 #define MDL_SEG_SIZE	0x1000 /* 4kbyte per segment */
    237 #define MDL_SEG_OFFSET	0x0FFF
    238 #define MDL_SIZE	(MAXPHYS / MDL_SEG_SIZE + 1) /* no hardware limit? */
    239 
    240 	if (bus_dmamap_create(esc->sc_dmat, MAXPHYS, MDL_SIZE, MDL_SEG_SIZE,
    241 	    MDL_SEG_SIZE, BUS_DMA_NOWAIT, &esc->sc_xfermap)) {
    242 		aprint_error(": can't create DMA maps\n");
    243 		return;
    244 	}
    245 
    246 	/*
    247 	 * Allocate and map memory for the MDL.
    248 	 */
    249 
    250 	if ((error = bus_dmamem_alloc(esc->sc_dmat,
    251 	    sizeof(uint32_t) * MDL_SIZE, PAGE_SIZE, 0, &seg, 1, &rseg,
    252 	    BUS_DMA_NOWAIT)) != 0) {
    253 		aprint_error(": unable to allocate memory for the MDL,"
    254 		    " error = %d\n", error);
    255 		goto fail_0;
    256 	}
    257 	if ((error = bus_dmamem_map(esc->sc_dmat, &seg, rseg,
    258 	    sizeof(uint32_t) * MDL_SIZE , (void **)&esc->sc_mdladdr,
    259 	    BUS_DMA_NOWAIT|BUS_DMA_COHERENT)) != 0) {
    260 		aprint_error(": unable to map the MDL memory, error = %d\n",
    261 		    error);
    262 		goto fail_1;
    263 	}
    264 	if ((error = bus_dmamap_create(esc->sc_dmat,
    265 	    sizeof(uint32_t) * MDL_SIZE, 1, sizeof(uint32_t) * MDL_SIZE,
    266 	    0, BUS_DMA_NOWAIT, &esc->sc_mdldmap)) != 0) {
    267 		aprint_error(": unable to map_create for the MDL, error = %d\n",
    268 		    error);
    269 		goto fail_2;
    270 	}
    271 	if ((error = bus_dmamap_load(esc->sc_dmat, esc->sc_mdldmap,
    272 	     esc->sc_mdladdr, sizeof(uint32_t) * MDL_SIZE,
    273 	     NULL, BUS_DMA_NOWAIT)) != 0) {
    274 		aprint_error(": unable to load for the MDL, error = %d\n",
    275 		    error);
    276 		goto fail_3;
    277 	}
    278 
    279 	/* map and establish interrupt */
    280 	if (pci_intr_map(pa, &ih)) {
    281 		aprint_error(": couldn't map interrupt\n");
    282 		goto fail_4;
    283 	}
    284 
    285 	intrstr = pci_intr_string(pa->pa_pc, ih);
    286 	esc->sc_ih = pci_intr_establish(pa->pa_pc, ih, IPL_BIO,
    287 	    ncr53c9x_intr, esc);
    288 	if (esc->sc_ih == NULL) {
    289 		aprint_error(": couldn't establish interrupt");
    290 		if (intrstr != NULL)
    291 			aprint_error(" at %s", intrstr);
    292 		aprint_error("\n");
    293 		goto fail_4;
    294 	}
    295 	if (intrstr != NULL) {
    296 		aprint_normal(": interrupting at %s\n", intrstr);
    297 		aprint_normal("%s", device_xname(sc->sc_dev));
    298 	}
    299 
    300 	/* Do the common parts of attachment. */
    301 	sc->sc_adapter.adapt_minphys = minphys;
    302 	sc->sc_adapter.adapt_request = ncr53c9x_scsipi_request;
    303 	ncr53c9x_attach(sc);
    304 
    305 	/* Turn on target selection using the `DMA' method */
    306 	sc->sc_features |= NCR_F_DMASELECT;
    307 
    308 	return;
    309 
    310  fail_4:
    311 	bus_dmamap_unload(esc->sc_dmat, esc->sc_mdldmap);
    312  fail_3:
    313 	bus_dmamap_destroy(esc->sc_dmat, esc->sc_mdldmap);
    314  fail_2:
    315 	bus_dmamem_unmap(esc->sc_dmat, (void *)esc->sc_mdldmap,
    316 	    sizeof(uint32_t) * MDL_SIZE);
    317  fail_1:
    318 	bus_dmamem_free(esc->sc_dmat, &seg, rseg);
    319  fail_0:
    320 	bus_dmamap_destroy(esc->sc_dmat, esc->sc_xfermap);
    321 }
    322 
    323 /*
    324  * Glue functions.
    325  */
    326 
    327 static uint8_t
    328 pcscp_read_reg(struct ncr53c9x_softc *sc, int reg)
    329 {
    330 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    331 
    332 	return PCSCP_READ_REG(esc, reg);
    333 }
    334 
    335 static void
    336 pcscp_write_reg(struct ncr53c9x_softc *sc, int reg, uint8_t v)
    337 {
    338 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    339 
    340 	PCSCP_WRITE_REG(esc, reg, v);
    341 }
    342 
    343 static int
    344 pcscp_dma_isintr(struct ncr53c9x_softc *sc)
    345 {
    346 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    347 
    348 	return (PCSCP_READ_REG(esc, NCR_STAT) & NCRSTAT_INT) != 0;
    349 }
    350 
    351 static void
    352 pcscp_dma_reset(struct ncr53c9x_softc *sc)
    353 {
    354 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    355 
    356 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE);
    357 
    358 	esc->sc_active = 0;
    359 }
    360 
    361 static int
    362 pcscp_dma_intr(struct ncr53c9x_softc *sc)
    363 {
    364 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    365 	int trans, resid, i;
    366 	bus_dmamap_t dmap = esc->sc_xfermap;
    367 	int datain = esc->sc_datain;
    368 	uint32_t dmastat;
    369 	uint8_t *p = NULL;
    370 
    371 	dmastat = READ_DMAREG(esc, DMA_STAT);
    372 
    373 	if (dmastat & DMASTAT_ERR) {
    374 		/* XXX not tested... */
    375 		WRITE_DMAREG(esc, DMA_CMD,
    376 		    DMACMD_ABORT | (datain ? DMACMD_DIR : 0));
    377 
    378 		printf("%s: error: DMA error detected; Aborting.\n",
    379 		    device_xname(sc->sc_dev));
    380 		bus_dmamap_unload(esc->sc_dmat, dmap);
    381 		return -1;
    382 	}
    383 
    384 	if (dmastat & DMASTAT_ABT) {
    385 		/* XXX What should be done? */
    386 		printf("%s: %s: DMA aborted.\n",
    387 		    device_xname(sc->sc_dev), __func__);
    388 		WRITE_DMAREG(esc, DMA_CMD,
    389 		    DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
    390 		esc->sc_active = 0;
    391 		return 0;
    392 	}
    393 
    394 #ifdef DIAGNOSTIC
    395 	/* This is an "assertion" :) */
    396 	if (esc->sc_active == 0)
    397 		panic("%s: %s: DMA wasn't active",
    398 		    device_xname(sc->sc_dev), __func__);
    399 #endif
    400 
    401 	/* DMA has stopped */
    402 
    403 	esc->sc_active = 0;
    404 
    405 	if (esc->sc_dmasize == 0) {
    406 		/* A "Transfer Pad" operation completed */
    407 		NCR_DMA(("%s: discarded %d bytes (tcl=%d, tcm=%d)\n",
    408 		    __func__,
    409 		    PCSCP_READ_REG(esc, NCR_TCL) |
    410 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8),
    411 		    PCSCP_READ_REG(esc, NCR_TCL),
    412 		    PCSCP_READ_REG(esc, NCR_TCM)));
    413 		return 0;
    414 	}
    415 
    416 	resid = 0;
    417 	/*
    418 	 * If a transfer onto the SCSI bus gets interrupted by the device
    419 	 * (e.g. for a SAVEPOINTER message), the data in the FIFO counts
    420 	 * as residual since the ESP counter registers get decremented as
    421 	 * bytes are clocked into the FIFO.
    422 	 */
    423 	if (!datain &&
    424 	    (resid = (PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
    425 		NCR_DMA(("%s: empty esp FIFO of %d ", __func__, resid));
    426 	}
    427 
    428 	if ((sc->sc_espstat & NCRSTAT_TC) == 0) {
    429 		/*
    430 		 * `Terminal count' is off, so read the residue
    431 		 * out of the ESP counter registers.
    432 		 */
    433 		if (datain) {
    434 			resid = PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
    435 			while (resid > 1)
    436 				resid =
    437 				    PCSCP_READ_REG(esc, NCR_FFLAG) & NCRFIFO_FF;
    438 			WRITE_DMAREG(esc, DMA_CMD, DMACMD_BLAST | DMACMD_MDL |
    439 			    (datain ? DMACMD_DIR : 0));
    440 
    441 			for (i = 0; i < 1000; i++) { /* XXX */
    442 				if (READ_DMAREG(esc, DMA_STAT) & DMASTAT_BCMP)
    443 					break;
    444 				DELAY(1);
    445 			}
    446 
    447 			/* See the below comments... */
    448 			if (resid)
    449 				p = *esc->sc_dmaaddr;
    450 		}
    451 
    452 		resid += PCSCP_READ_REG(esc, NCR_TCL) |
    453 		    (PCSCP_READ_REG(esc, NCR_TCM) << 8) |
    454 		    (PCSCP_READ_REG(esc, NCR_TCH) << 16);
    455 	} else {
    456 		while ((dmastat & DMASTAT_DONE) == 0)
    457 			dmastat = READ_DMAREG(esc, DMA_STAT);
    458 	}
    459 
    460 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
    461 
    462 	/* sync MDL */
    463 	bus_dmamap_sync(esc->sc_dmat, esc->sc_mdldmap,
    464 	    0, sizeof(uint32_t) * dmap->dm_nsegs, BUS_DMASYNC_POSTWRITE);
    465 	/* sync transfer buffer */
    466 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
    467 	    datain ? BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
    468 	bus_dmamap_unload(esc->sc_dmat, dmap);
    469 
    470 	trans = esc->sc_dmasize - resid;
    471 
    472 	/*
    473 	 * From the technical manual notes:
    474 	 *
    475 	 * `In some odd byte conditions, one residual byte will be left
    476 	 *  in the SCSI FIFO, and the FIFO flags will never count to 0.
    477 	 *  When this happens, the residual byte should be retrieved
    478 	 *  via PIO following completion of the BLAST operation.'
    479 	 */
    480 
    481 	if (p) {
    482 		p += trans;
    483 		*p = PCSCP_READ_REG(esc, NCR_FIFO);
    484 		trans++;
    485 	}
    486 
    487 	if (trans < 0) {			/* transferred < 0 ? */
    488 #if 0
    489 		/*
    490 		 * This situation can happen in perfectly normal operation
    491 		 * if the ESP is reselected while using DMA to select
    492 		 * another target.  As such, don't print the warning.
    493 		 */
    494 		printf("%s: xfer (%d) > req (%d)\n",
    495 		    device_xname(sc->sc_dev), trans, esc->sc_dmasize);
    496 #endif
    497 		trans = esc->sc_dmasize;
    498 	}
    499 
    500 	NCR_DMA(("%s: tcl=%d, tcm=%d, tch=%d; trans=%d, resid=%d\n",
    501 	    __func__,
    502 	    PCSCP_READ_REG(esc, NCR_TCL),
    503 	    PCSCP_READ_REG(esc, NCR_TCM),
    504 	    PCSCP_READ_REG(esc, NCR_TCH),
    505 	    trans, resid));
    506 
    507 	*esc->sc_dmalen -= trans;
    508 	*esc->sc_dmaaddr += trans;
    509 
    510 	return 0;
    511 }
    512 
    513 static int
    514 pcscp_dma_setup(struct ncr53c9x_softc *sc, uint8_t **addr, size_t *len,
    515     int datain, size_t *dmasize)
    516 {
    517 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    518 	bus_dmamap_t dmap = esc->sc_xfermap;
    519 	uint32_t *mdl;
    520 	int error, nseg, seg;
    521 	bus_addr_t s_offset, s_addr;
    522 
    523 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | (datain ? DMACMD_DIR : 0));
    524 
    525 	esc->sc_dmaaddr = addr;
    526 	esc->sc_dmalen = len;
    527 	esc->sc_dmasize = *dmasize;
    528 	esc->sc_datain = datain;
    529 
    530 #ifdef DIAGNOSTIC
    531 	if ((*dmasize / MDL_SEG_SIZE) > MDL_SIZE)
    532 		panic("%s: transfer size too large", device_xname(sc->sc_dev));
    533 #endif
    534 
    535 	/*
    536 	 * No need to set up DMA in `Transfer Pad' operation.
    537 	 * (case of *dmasize == 0)
    538 	 */
    539 	if (*dmasize == 0)
    540 		return 0;
    541 
    542 	error = bus_dmamap_load(esc->sc_dmat, dmap, *esc->sc_dmaaddr,
    543 	    *esc->sc_dmalen, NULL,
    544 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_NOSLEEP) ?
    545 	    BUS_DMA_NOWAIT : BUS_DMA_WAITOK) | BUS_DMA_STREAMING |
    546 	    ((sc->sc_nexus->xs->xs_control & XS_CTL_DATA_IN) ?
    547 	     BUS_DMA_READ : BUS_DMA_WRITE));
    548 	if (error) {
    549 		printf("%s: unable to load dmamap, error = %d\n",
    550 		    device_xname(sc->sc_dev), error);
    551 		return error;
    552 	}
    553 
    554 	/* set transfer length */
    555 	WRITE_DMAREG(esc, DMA_STC, *dmasize);
    556 
    557 	/* set up MDL */
    558 	mdl = esc->sc_mdladdr;
    559 	nseg = dmap->dm_nsegs;
    560 
    561 	/* the first segment is possibly not aligned with 4k MDL boundary */
    562 	s_addr = dmap->dm_segs[0].ds_addr;
    563 	s_offset = s_addr & MDL_SEG_OFFSET;
    564 	s_addr -= s_offset;
    565 
    566 	/* set the first MDL and offset */
    567 	WRITE_DMAREG(esc, DMA_SPA, s_offset);
    568 	*mdl++ = htole32(s_addr);
    569 
    570 	/* the rest dmamap segments are aligned with 4k boundary */
    571 	for (seg = 1; seg < nseg; seg++)
    572 		*mdl++ = htole32(dmap->dm_segs[seg].ds_addr);
    573 
    574 	return 0;
    575 }
    576 
    577 static void
    578 pcscp_dma_go(struct ncr53c9x_softc *sc)
    579 {
    580 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    581 	bus_dmamap_t dmap = esc->sc_xfermap, mdldmap = esc->sc_mdldmap;
    582 	int datain = esc->sc_datain;
    583 
    584 	/* No DMA transfer in Transfer Pad operation */
    585 	if (esc->sc_dmasize == 0)
    586 		return;
    587 
    588 	/* sync transfer buffer */
    589 	bus_dmamap_sync(esc->sc_dmat, dmap, 0, dmap->dm_mapsize,
    590 	    datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
    591 
    592 	/* sync MDL */
    593 	bus_dmamap_sync(esc->sc_dmat, mdldmap,
    594 	    0, sizeof(uint32_t) * dmap->dm_nsegs, BUS_DMASYNC_PREWRITE);
    595 
    596 	/* set Starting MDL Address */
    597 	WRITE_DMAREG(esc, DMA_SMDLA, mdldmap->dm_segs[0].ds_addr);
    598 
    599 	/* set DMA command register bits */
    600 	/* XXX DMA Transfer Interrupt Enable bit is broken? */
    601 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_IDLE | DMACMD_MDL |
    602 	    /* DMACMD_INTE | */
    603 	    (datain ? DMACMD_DIR : 0));
    604 
    605 	/* issue DMA start command */
    606 	WRITE_DMAREG(esc, DMA_CMD, DMACMD_START | DMACMD_MDL |
    607 	    /* DMACMD_INTE | */
    608 	    (datain ? DMACMD_DIR : 0));
    609 
    610 	esc->sc_active = 1;
    611 }
    612 
    613 static void
    614 pcscp_dma_stop(struct ncr53c9x_softc *sc)
    615 {
    616 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    617 
    618 	/* DMA stop */
    619 	/* XXX What should we do here ? */
    620 	WRITE_DMAREG(esc, DMA_CMD,
    621 	    DMACMD_ABORT | (esc->sc_datain ? DMACMD_DIR : 0));
    622 	bus_dmamap_unload(esc->sc_dmat, esc->sc_xfermap);
    623 
    624 	esc->sc_active = 0;
    625 }
    626 
    627 static int
    628 pcscp_dma_isactive(struct ncr53c9x_softc *sc)
    629 {
    630 	struct pcscp_softc *esc = (struct pcscp_softc *)sc;
    631 
    632 	/* XXX should check esc->sc_active? */
    633 	if ((READ_DMAREG(esc, DMA_CMD) & DMACMD_CMD) != DMACMD_IDLE)
    634 		return 1;
    635 	return 0;
    636 }
    637