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asc_tcds.c revision 1.16
      1 /* $NetBSD: asc_tcds.c,v 1.16 2006/03/31 17:39:33 thorpej Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1998 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.
     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  * Copyright (c) 1994 Peter Galbavy.  All rights reserved.
     42  *
     43  * Redistribution and use in source and binary forms, with or without
     44  * modification, are permitted provided that the following conditions
     45  * are met:
     46  * 1. Redistributions of source code must retain the above copyright
     47  *    notice, this list of conditions and the following disclaimer.
     48  * 2. Redistributions in binary form must reproduce the above copyright
     49  *    notice, this list of conditions and the following disclaimer in the
     50  *    documentation and/or other materials provided with the distribution.
     51  * 3. All advertising materials mentioning features or use of this software
     52  *    must display the following acknowledgement:
     53  *	This product includes software developed by Peter Galbavy.
     54  * 4. The name of the author may not be used to endorse or promote products
     55  *    derived from this software without specific prior written permission.
     56  *
     57  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     58  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     59  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     60  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     61  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     62  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     63  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     64  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     65  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     66  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     67  */
     68 
     69 #include <sys/cdefs.h>
     70 __KERNEL_RCSID(0, "$NetBSD: asc_tcds.c,v 1.16 2006/03/31 17:39:33 thorpej Exp $");
     71 
     72 #include <sys/param.h>
     73 #include <sys/systm.h>
     74 #include <sys/device.h>
     75 #include <sys/buf.h>
     76 
     77 #include <uvm/uvm_extern.h>
     78 
     79 #include <dev/scsipi/scsi_all.h>
     80 #include <dev/scsipi/scsipi_all.h>
     81 #include <dev/scsipi/scsiconf.h>
     82 
     83 #include <dev/ic/ncr53c9xreg.h>
     84 #include <dev/ic/ncr53c9xvar.h>
     85 
     86 #include <machine/bus.h>
     87 
     88 #include <dev/tc/tcvar.h>
     89 #include <dev/tc/tcdsreg.h>
     90 #include <dev/tc/tcdsvar.h>
     91 
     92 struct asc_softc {
     93 	struct ncr53c9x_softc sc_ncr53c9x;	/* glue to MI code */
     94 	bus_space_tag_t sc_bst;			/* bus space tag */
     95 	bus_space_handle_t sc_scsi_bsh;		/* ASC register handle */
     96 	bus_dma_tag_t sc_dmat;			/* bus DMA tag */
     97 	bus_dmamap_t sc_dmamap;			/* bus dmamap */
     98 	caddr_t *sc_dmaaddr;
     99 	size_t *sc_dmalen;
    100 	size_t sc_dmasize;
    101 	unsigned sc_flags;
    102 #define	ASC_ISPULLUP		0x01
    103 #define	ASC_DMAACTIVE		0x02
    104 #define	ASC_MAPLOADED		0x04
    105 	struct tcds_slotconfig *sc_tcds;	/* DMA/slot info lives here */
    106 };
    107 
    108 static int  asc_tcds_match (struct device *, struct cfdata *, void *);
    109 static void asc_tcds_attach(struct device *, struct device *, void *);
    110 
    111 CFATTACH_DECL(asc_tcds, sizeof(struct asc_softc),
    112     asc_tcds_match, asc_tcds_attach, NULL, NULL);
    113 
    114 /*
    115  * Functions and the switch for the MI code.
    116  */
    117 static u_char	asc_read_reg(struct ncr53c9x_softc *, int);
    118 static void	asc_write_reg(struct ncr53c9x_softc *, int, u_char);
    119 static int	tcds_dma_isintr(struct ncr53c9x_softc *);
    120 static void	tcds_dma_reset(struct ncr53c9x_softc *);
    121 static int	tcds_dma_intr(struct ncr53c9x_softc *);
    122 static int	tcds_dma_setup(struct ncr53c9x_softc *, caddr_t *,
    123 	    size_t *, int, size_t *);
    124 static void	tcds_dma_go(struct ncr53c9x_softc *);
    125 static void	tcds_dma_stop(struct ncr53c9x_softc *);
    126 static int	tcds_dma_isactive(struct ncr53c9x_softc *);
    127 static void	tcds_clear_latched_intr(struct ncr53c9x_softc *);
    128 
    129 static struct ncr53c9x_glue asc_tcds_glue = {
    130 	asc_read_reg,
    131 	asc_write_reg,
    132 	tcds_dma_isintr,
    133 	tcds_dma_reset,
    134 	tcds_dma_intr,
    135 	tcds_dma_setup,
    136 	tcds_dma_go,
    137 	tcds_dma_stop,
    138 	tcds_dma_isactive,
    139 	tcds_clear_latched_intr,
    140 };
    141 
    142 static int
    143 asc_tcds_match(struct device *parent, struct cfdata *cf, void *aux)
    144 {
    145 
    146 	/* We always exist. */
    147 	return 1;
    148 }
    149 
    150 #define DMAMAX(a)	(PAGE_SIZE - ((a) & (PAGE_SIZE - 1)))
    151 
    152 /*
    153  * Attach this instance, and then all the sub-devices
    154  */
    155 static void
    156 asc_tcds_attach(struct device *parent, struct device *self, void *aux)
    157 {
    158 	struct tcdsdev_attach_args *tcdsdev = aux;
    159 	struct asc_softc *asc = device_private(self);
    160 	struct ncr53c9x_softc *sc = &asc->sc_ncr53c9x;
    161 	int error;
    162 
    163 	/*
    164 	 * Set up glue for MI code early; we use some of it here.
    165 	 */
    166 	sc->sc_glue = &asc_tcds_glue;
    167 
    168 	asc->sc_bst = tcdsdev->tcdsda_bst;
    169 	asc->sc_scsi_bsh = tcdsdev->tcdsda_bsh;
    170 	asc->sc_tcds = tcdsdev->tcdsda_sc;
    171 
    172 	/*
    173 	 * The TCDS ASIC cannot DMA across 8k boundaries, and this
    174 	 * driver is written such that each DMA segment gets a new
    175 	 * call to tcds_dma_setup().  Thus, the DMA map only needs
    176 	 * to support 8k transfers.
    177 	 */
    178 	asc->sc_dmat = tcdsdev->tcdsda_dmat;
    179 	if ((error = bus_dmamap_create(asc->sc_dmat, PAGE_SIZE, 1, PAGE_SIZE,
    180 	    PAGE_SIZE, BUS_DMA_NOWAIT, &asc->sc_dmamap)) < 0) {
    181 		printf("failed to create DMA map, error = %d\n", error);
    182 	}
    183 
    184 	sc->sc_id = tcdsdev->tcdsda_id;
    185 	sc->sc_freq = tcdsdev->tcdsda_freq;
    186 
    187 	/* gimme MHz */
    188 	sc->sc_freq /= 1000000;
    189 
    190 	tcds_intr_establish(parent, tcdsdev->tcdsda_chip, ncr53c9x_intr, sc);
    191 
    192 	/*
    193 	 * XXX More of this should be in ncr53c9x_attach(), but
    194 	 * XXX should we really poke around the chip that much in
    195 	 * XXX the MI code?  Think about this more...
    196 	 */
    197 
    198 	/*
    199 	 * Set up static configuration info.
    200 	 */
    201 	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
    202 	sc->sc_cfg2 = NCRCFG2_SCSI2;
    203 	sc->sc_cfg3 = NCRCFG3_CDB;
    204 	if (sc->sc_freq > 25)
    205 		sc->sc_cfg3 |= NCRF9XCFG3_FCLK;
    206 	sc->sc_rev = tcdsdev->tcdsda_variant;
    207 	if (tcdsdev->tcdsda_fast) {
    208 		sc->sc_features |= NCR_F_FASTSCSI;
    209 		sc->sc_cfg3_fscsi = NCRF9XCFG3_FSCSI;
    210 	}
    211 
    212 	/*
    213 	 * XXX minsync and maxxfer _should_ be set up in MI code,
    214 	 * XXX but it appears to have some dependency on what sort
    215 	 * XXX of DMA we're hooked up to, etc.
    216 	 */
    217 
    218 	/*
    219 	 * This is the value used to start sync negotiations
    220 	 * Note that the NCR register "SYNCTP" is programmed
    221 	 * in "clocks per byte", and has a minimum value of 4.
    222 	 * The SCSI period used in negotiation is one-fourth
    223 	 * of the time (in nanoseconds) needed to transfer one byte.
    224 	 * Since the chip's clock is given in MHz, we have the following
    225 	 * formula: 4 * period = (1000 / freq) * 4
    226 	 */
    227 	sc->sc_minsync = (1000 / sc->sc_freq) * tcdsdev->tcdsda_period / 4;
    228 
    229 	sc->sc_maxxfer = 64 * 1024;
    230 
    231 	/* Do the common parts of attachment. */
    232 	sc->sc_adapter.adapt_minphys = minphys;
    233 	sc->sc_adapter.adapt_request = ncr53c9x_scsipi_request;
    234 	ncr53c9x_attach(sc);
    235 }
    236 
    237 static void
    238 tcds_dma_reset(struct ncr53c9x_softc *sc)
    239 {
    240 	struct asc_softc *asc = (struct asc_softc *)sc;
    241 
    242 	/* TCDS SCSI disable/reset/enable. */
    243 	tcds_scsi_reset(asc->sc_tcds);			/* XXX */
    244 
    245 	if (asc->sc_flags & ASC_MAPLOADED)
    246 		bus_dmamap_unload(asc->sc_dmat, asc->sc_dmamap);
    247 	asc->sc_flags &= ~(ASC_DMAACTIVE|ASC_MAPLOADED);
    248 }
    249 
    250 /*
    251  * start a DMA transfer or keep it going
    252  */
    253 int
    254 tcds_dma_setup(struct ncr53c9x_softc *sc, caddr_t *addr, size_t *len,
    255     int ispullup, size_t *dmasize)
    256 {
    257 	struct asc_softc *asc = (struct asc_softc *)sc;
    258 	struct tcds_slotconfig *tcds = asc->sc_tcds;
    259 	size_t size;
    260 	u_int32_t dic;
    261 
    262 	NCR_DMA(("tcds_dma %d: start %d@%p,%s\n", tcds->sc_slot,
    263 		(int)*asc->sc_dmalen, *asc->sc_dmaaddr,
    264 		(ispullup) ? "IN" : "OUT"));
    265 
    266 	/*
    267 	 * the rules say we cannot transfer more than the limit
    268 	 * of this DMA chip (64k) and we cannot cross a 8k boundary.
    269 	 */
    270 	size = min(*dmasize, DMAMAX((size_t)*addr));
    271 	asc->sc_dmaaddr = addr;
    272 	asc->sc_dmalen = len;
    273 	asc->sc_flags = (ispullup) ? ASC_ISPULLUP : 0;
    274 	*dmasize = asc->sc_dmasize = size;
    275 
    276 	NCR_DMA(("dma_start: dmasize = %d\n", (int)size));
    277 
    278 	if (size == 0)
    279 		return 0;
    280 
    281 	if (bus_dmamap_load(asc->sc_dmat, asc->sc_dmamap, *addr, size,
    282 	    NULL, BUS_DMA_NOWAIT | (ispullup ? BUS_DMA_READ : BUS_DMA_WRITE))) {
    283 		/*
    284 		 * XXX Should return an error, here, but the upper-layer
    285 		 * XXX doesn't check the return value!
    286 		 */
    287 		panic("tcds_dma_setup: dmamap load failed");
    288 	}
    289 
    290 	/* synchronize dmamap contents with memory image */
    291 	bus_dmamap_sync(asc->sc_dmat, asc->sc_dmamap, 0, size,
    292 		(ispullup) ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
    293 
    294 	/* load address, set/clear unaligned transfer and read/write bits. */
    295 	bus_space_write_4(tcds->sc_bst, tcds->sc_bsh, tcds->sc_sda,
    296 	    asc->sc_dmamap->dm_segs[0].ds_addr >> 2);
    297 	dic = bus_space_read_4(tcds->sc_bst, tcds->sc_bsh, tcds->sc_dic);
    298 	dic &= ~TCDS_DIC_ADDRMASK;
    299 	dic |= asc->sc_dmamap->dm_segs[0].ds_addr & TCDS_DIC_ADDRMASK;
    300 	if (ispullup)
    301 		dic |= TCDS_DIC_WRITE;
    302 	else
    303 		dic &= ~TCDS_DIC_WRITE;
    304 	bus_space_write_4(tcds->sc_bst, tcds->sc_bsh, tcds->sc_dic, dic);
    305 
    306 	asc->sc_flags |= ASC_MAPLOADED;
    307 	return 0;
    308 }
    309 
    310 static void
    311 tcds_dma_go(struct ncr53c9x_softc *sc)
    312 {
    313 	struct asc_softc *asc = (struct asc_softc *)sc;
    314 
    315 	/* mark unit as DMA-active */
    316 	asc->sc_flags |= ASC_DMAACTIVE;
    317 
    318 	/* start DMA */
    319 	tcds_dma_enable(asc->sc_tcds, 1);
    320 }
    321 
    322 static void
    323 tcds_dma_stop(struct ncr53c9x_softc *sc)
    324 {
    325 #if 0
    326 	struct asc_softc *asc = (struct asc_softc *)sc;
    327 #endif
    328 
    329 	/*
    330 	 * XXX STOP DMA HERE!
    331 	 */
    332 }
    333 
    334 /*
    335  * Pseudo (chained) interrupt from the asc driver to kick the
    336  * current running DMA transfer. Called from ncr53c9x_intr()
    337  * for now.
    338  *
    339  * return 1 if it was a DMA continue.
    340  */
    341 static int
    342 tcds_dma_intr(struct ncr53c9x_softc *sc)
    343 {
    344 	struct asc_softc *asc = (struct asc_softc *)sc;
    345 	struct tcds_slotconfig *tcds = asc->sc_tcds;
    346 	int trans, resid;
    347 	u_int32_t tcl, tcm;
    348 	u_int32_t dud, dudmask, *addr;
    349 	bus_addr_t pa;
    350 
    351 	NCR_DMA(("tcds_dma %d: intr", tcds->sc_slot));
    352 
    353 	if (tcds_scsi_iserr(tcds))
    354 		return 0;
    355 
    356 	/* This is an "assertion" :) */
    357 	if ((asc->sc_flags & ASC_DMAACTIVE) == 0)
    358 		panic("tcds_dma_intr: DMA wasn't active");
    359 
    360 	/* DMA has stopped */
    361 	tcds_dma_enable(tcds, 0);
    362 	asc->sc_flags &= ~ASC_DMAACTIVE;
    363 
    364 	if (asc->sc_dmasize == 0) {
    365 		/* A "Transfer Pad" operation completed */
    366 		tcl = NCR_READ_REG(sc, NCR_TCL);
    367 		tcm = NCR_READ_REG(sc, NCR_TCM);
    368 		NCR_DMA(("dma_intr: discarded %d bytes (tcl=%d, tcm=%d)\n",
    369 		    tcl | (tcm << 8), tcl, tcm));
    370 		return 0;
    371 	}
    372 
    373 	resid = 0;
    374 	if ((asc->sc_flags & ASC_ISPULLUP) == 0 &&
    375 	    (resid = (NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
    376 		NCR_DMA(("dma_intr: empty esp FIFO of %d ", resid));
    377 		DELAY(1);
    378 	}
    379 
    380 	resid += (tcl = NCR_READ_REG(sc, NCR_TCL));
    381 	resid += (tcm = NCR_READ_REG(sc, NCR_TCM)) << 8;
    382 
    383 	trans = asc->sc_dmasize - resid;
    384 	if (trans < 0) {			/* transferred < 0 ? */
    385 		printf("tcds_dma %d: xfer (%d) > req (%d)\n",
    386 		    tcds->sc_slot, trans, (int)asc->sc_dmasize);
    387 		trans = asc->sc_dmasize;
    388 	}
    389 
    390 	NCR_DMA(("dma_intr: tcl=%d, tcm=%d; trans=%d, resid=%d\n",
    391 	    tcl, tcm, trans, resid));
    392 
    393 	*asc->sc_dmalen -= trans;
    394 	*asc->sc_dmaaddr += trans;
    395 
    396 	bus_dmamap_sync(asc->sc_dmat, asc->sc_dmamap,
    397 			0, asc->sc_dmamap->dm_mapsize,
    398 			(sc->sc_flags & ASC_ISPULLUP)
    399 				? BUS_DMASYNC_POSTREAD
    400 				: BUS_DMASYNC_POSTWRITE);
    401 
    402 	/*
    403 	 * Clean up unaligned DMAs into main memory.
    404 	 */
    405 	if (asc->sc_flags & ASC_ISPULLUP) {
    406 		/* Handle unaligned starting address, length. */
    407 		dud = bus_space_read_4(tcds->sc_bst,
    408 		    tcds->sc_bsh, tcds->sc_dud0);
    409 		if ((dud & TCDS_DUD0_VALIDBITS) != 0) {
    410 			addr = (u_int32_t *)
    411 			    ((paddr_t)*asc->sc_dmaaddr & ~0x3);
    412 			dudmask = 0;
    413 			if (dud & TCDS_DUD0_VALID00)
    414 				panic("tcds_dma: dud0 byte 0 valid");
    415 			if (dud & TCDS_DUD0_VALID01)
    416 				dudmask |= TCDS_DUD_BYTE01;
    417 			if (dud & TCDS_DUD0_VALID10)
    418 				dudmask |= TCDS_DUD_BYTE10;
    419 #ifdef DIAGNOSTIC
    420 			if (dud & TCDS_DUD0_VALID11)
    421 				dudmask |= TCDS_DUD_BYTE11;
    422 #endif
    423 			NCR_DMA(("dud0 at %p dudmask 0x%x\n",
    424 			    addr, dudmask));
    425 			*addr = (*addr & ~dudmask) | (dud & dudmask);
    426 		}
    427 		dud = bus_space_read_4(tcds->sc_bst,
    428 		    tcds->sc_bsh, tcds->sc_dud1);
    429 		if ((dud & TCDS_DUD1_VALIDBITS) != 0) {
    430 			pa = bus_space_read_4(tcds->sc_bst, tcds->sc_bsh,
    431 			    tcds->sc_sda) << 2;
    432 			dudmask = 0;
    433 			if (dud & TCDS_DUD1_VALID00)
    434 				dudmask |= TCDS_DUD_BYTE00;
    435 			if (dud & TCDS_DUD1_VALID01)
    436 				dudmask |= TCDS_DUD_BYTE01;
    437 			if (dud & TCDS_DUD1_VALID10)
    438 				dudmask |= TCDS_DUD_BYTE10;
    439 #ifdef DIAGNOSTIC
    440 			if (dud & TCDS_DUD1_VALID11)
    441 				panic("tcds_dma: dud1 byte 3 valid");
    442 #endif
    443 			NCR_DMA(("dud1 at 0x%lx dudmask 0x%x\n",
    444 			    pa, dudmask));
    445 			/* XXX Fix TC_PHYS_TO_UNCACHED() */
    446 #if defined(__alpha__)
    447 			addr = (u_int32_t *)ALPHA_PHYS_TO_K0SEG(pa);
    448 #elif defined(__mips__)
    449 			addr = (u_int32_t *)MIPS_PHYS_TO_KSEG1(pa);
    450 #else
    451 #error TURBOchannel only exists on DECs, folks...
    452 #endif
    453 			*addr = (*addr & ~dudmask) | (dud & dudmask);
    454 		}
    455 		/* XXX deal with saved residual byte? */
    456 	}
    457 
    458 	bus_dmamap_unload(asc->sc_dmat, asc->sc_dmamap);
    459 	asc->sc_flags &= ~ASC_MAPLOADED;
    460 
    461 	return 0;
    462 }
    463 
    464 /*
    465  * Glue functions.
    466  */
    467 static u_char
    468 asc_read_reg(struct ncr53c9x_softc *sc, int reg)
    469 {
    470 	struct asc_softc *asc = (struct asc_softc *)sc;
    471 	u_int32_t v;
    472 
    473 	v = bus_space_read_4(asc->sc_bst, asc->sc_scsi_bsh,
    474 	    reg * sizeof(u_int32_t));
    475 
    476 	return v & 0xff;
    477 }
    478 
    479 static void
    480 asc_write_reg(struct ncr53c9x_softc *sc, int reg, u_char val)
    481 {
    482 	struct asc_softc *asc = (struct asc_softc *)sc;
    483 
    484 	bus_space_write_4(asc->sc_bst, asc->sc_scsi_bsh,
    485 	    reg * sizeof(u_int32_t), val);
    486 }
    487 
    488 static int
    489 tcds_dma_isintr(struct ncr53c9x_softc *sc)
    490 {
    491 	struct asc_softc *asc = (struct asc_softc *)sc;
    492 	int x;
    493 
    494 	x = tcds_scsi_isintr(asc->sc_tcds, 1);
    495 
    496 	/* XXX */
    497 	return x;
    498 }
    499 
    500 static int
    501 tcds_dma_isactive(struct ncr53c9x_softc *sc)
    502 {
    503 	struct asc_softc *asc = (struct asc_softc *)sc;
    504 
    505 	return !!(asc->sc_flags & ASC_DMAACTIVE);
    506 }
    507 
    508 static void
    509 tcds_clear_latched_intr(struct ncr53c9x_softc *sc)
    510 {
    511 	struct asc_softc *asc = (struct asc_softc *)sc;
    512 
    513 	/* Clear the TCDS interrupt bit. */
    514 	(void)tcds_scsi_isintr(asc->sc_tcds, 1);
    515 }
    516