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isadma.c revision 1.27
      1 /*	$NetBSD: isadma.c,v 1.27 1997/07/27 01:16:57 augustss Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1997 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  * Device driver for the ISA on-board DMA controller.
     42  */
     43 
     44 #include <sys/param.h>
     45 #include <sys/systm.h>
     46 #include <sys/proc.h>
     47 #include <sys/device.h>
     48 
     49 #include <vm/vm.h>
     50 
     51 #include <machine/bus.h>
     52 
     53 #include <dev/isa/isareg.h>
     54 #include <dev/isa/isavar.h>
     55 #include <dev/isa/isadmavar.h>
     56 #include <dev/isa/isadmareg.h>
     57 
     58 /* Used by isa_malloc() */
     59 #include <sys/malloc.h>
     60 struct isa_mem {
     61 	struct device *isadev;
     62 	int chan;
     63 	bus_size_t size;
     64 	bus_addr_t addr;
     65 	caddr_t kva;
     66 	struct isa_mem *next;
     67 } *isa_mem_head = 0;
     68 
     69 /*
     70  * High byte of DMA address is stored in this DMAPG register for
     71  * the Nth DMA channel.
     72  */
     73 static int dmapageport[2][4] = {
     74 	{0x7, 0x3, 0x1, 0x2},
     75 	{0xf, 0xb, 0x9, 0xa}
     76 };
     77 
     78 static u_int8_t dmamode[4] = {
     79 	DMA37MD_READ | DMA37MD_SINGLE,
     80 	DMA37MD_WRITE | DMA37MD_SINGLE,
     81 	DMA37MD_READ | DMA37MD_SINGLE | DMA37MD_LOOP,
     82 	DMA37MD_WRITE | DMA37MD_SINGLE | DMA37MD_LOOP
     83 };
     84 
     85 static inline void isa_dmaunmask __P((struct isa_softc *, int));
     86 static inline void isa_dmamask __P((struct isa_softc *, int));
     87 
     88 static inline void
     89 isa_dmaunmask(sc, chan)
     90 	struct isa_softc *sc;
     91 	int chan;
     92 {
     93 	int ochan = chan & 3;
     94 
     95 	/* set dma channel mode, and set dma channel mode */
     96 	if ((chan & 4) == 0)
     97 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h,
     98 		    DMA1_SMSK, ochan | DMA37SM_CLEAR);
     99 	else
    100 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h,
    101 		    DMA2_SMSK, ochan | DMA37SM_CLEAR);
    102 }
    103 
    104 static inline void
    105 isa_dmamask(sc, chan)
    106 	struct isa_softc *sc;
    107 	int chan;
    108 {
    109 	int ochan = chan & 3;
    110 
    111 	/* set dma channel mode, and set dma channel mode */
    112 	if ((chan & 4) == 0) {
    113 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h,
    114 		    DMA1_SMSK, ochan | DMA37SM_SET);
    115 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h,
    116 		    DMA1_FFC, 0);
    117 	} else {
    118 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h,
    119 		    DMA2_SMSK, ochan | DMA37SM_SET);
    120 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h,
    121 		    DMA2_FFC, 0);
    122 	}
    123 }
    124 
    125 /*
    126  * isa_dmacascade(): program 8237 DMA controller channel to accept
    127  * external dma control by a board.
    128  */
    129 void
    130 isa_dmacascade(isadev, chan)
    131 	struct device *isadev;
    132 	int chan;
    133 {
    134 	struct isa_softc *sc = (struct isa_softc *)isadev;
    135 	int ochan = chan & 3;
    136 
    137 	if (chan < 0 || chan > 7) {
    138 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    139 		goto lose;
    140 	}
    141 
    142 	if (ISA_DRQ_ISFREE(sc, chan) == 0) {
    143 		printf("%s: DRQ %d is not free\n", sc->sc_dev.dv_xname, chan);
    144 		goto lose;
    145 	}
    146 
    147 	ISA_DRQ_ALLOC(sc, chan);
    148 
    149 	/* set dma channel mode, and set dma channel mode */
    150 	if ((chan & 4) == 0)
    151 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h,
    152 		    DMA1_MODE, ochan | DMA37MD_CASCADE);
    153 	else
    154 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h,
    155 		    DMA2_MODE, ochan | DMA37MD_CASCADE);
    156 
    157 	isa_dmaunmask(sc, chan);
    158 	return;
    159 
    160  lose:
    161 	panic("isa_dmacascade");
    162 }
    163 
    164 int
    165 isa_dmamap_create(isadev, chan, size, flags)
    166 	struct device *isadev;
    167 	int chan;
    168 	bus_size_t size;
    169 	int flags;
    170 {
    171 	struct isa_softc *sc = (struct isa_softc *)isadev;
    172 	bus_size_t maxsize;
    173 
    174 	if (chan < 0 || chan > 7) {
    175 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    176 		goto lose;
    177 	}
    178 
    179 	if (chan & 4)
    180 		maxsize = (1 << 17);
    181 	else
    182 		maxsize = (1 << 16);
    183 
    184 	if (size > maxsize)
    185 		return (EINVAL);
    186 
    187 	if (ISA_DRQ_ISFREE(sc, chan) == 0) {
    188 		printf("%s: drq %d is not free\n", sc->sc_dev.dv_xname, chan);
    189 		goto lose;
    190 	}
    191 
    192 	ISA_DRQ_ALLOC(sc, chan);
    193 
    194 	return (bus_dmamap_create(sc->sc_dmat, size, 1, size, maxsize,
    195 	    flags, &sc->sc_dmamaps[chan]));
    196 
    197  lose:
    198 	panic("isa_dmamap_create");
    199 }
    200 
    201 void
    202 isa_dmamap_destroy(isadev, chan)
    203 	struct device *isadev;
    204 	int chan;
    205 {
    206 	struct isa_softc *sc = (struct isa_softc *)isadev;
    207 
    208 	if (chan < 0 || chan > 7) {
    209 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    210 		goto lose;
    211 	}
    212 
    213 	if (ISA_DRQ_ISFREE(sc, chan)) {
    214 		printf("%s: drq %d is already free\n",
    215 		    sc->sc_dev.dv_xname, chan);
    216 		goto lose;
    217 	}
    218 
    219 	ISA_DRQ_FREE(sc, chan);
    220 
    221 	bus_dmamap_destroy(sc->sc_dmat, sc->sc_dmamaps[chan]);
    222 	return;
    223 
    224  lose:
    225 	panic("isa_dmamap_destroy");
    226 }
    227 
    228 /*
    229  * isa_dmastart(): program 8237 DMA controller channel and set it
    230  * in motion.
    231  */
    232 int
    233 isa_dmastart(isadev, chan, addr, nbytes, p, flags, busdmaflags)
    234 	struct device *isadev;
    235 	int chan;
    236 	void *addr;
    237 	bus_size_t nbytes;
    238 	struct proc *p;
    239 	int flags;
    240 	int busdmaflags;
    241 {
    242 	struct isa_softc *sc = (struct isa_softc *)isadev;
    243 	bus_dmamap_t dmam;
    244 	bus_addr_t dmaaddr;
    245 	int waport;
    246 	int ochan = chan & 3;
    247 	int error;
    248 
    249 	if (chan < 0 || chan > 7) {
    250 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    251 		goto lose;
    252 	}
    253 
    254 #ifdef ISADMA_DEBUG
    255 	printf("isa_dmastart: drq %d, addr %p, nbytes 0x%lx, p %p, "
    256 	    "flags 0x%x, dmaflags 0x%x\n",
    257 	    chan, addr, nbytes, p, flags, busdmaflags);
    258 #endif
    259 
    260 	if (chan & 4) {
    261 		if (nbytes > (1 << 17) || nbytes & 1 || (u_long)addr & 1) {
    262 			printf("%s: drq %d, nbytes 0x%lx, addr %p\n",
    263 			    sc->sc_dev.dv_xname, chan, nbytes, addr);
    264 			goto lose;
    265 		}
    266 	} else {
    267 		if (nbytes > (1 << 16)) {
    268 			printf("%s: drq %d, nbytes 0x%lx\n",
    269 			    sc->sc_dev.dv_xname, chan, nbytes);
    270 			goto lose;
    271 		}
    272 	}
    273 
    274 	dmam = sc->sc_dmamaps[chan];
    275 
    276 	error = bus_dmamap_load(sc->sc_dmat, dmam, addr, nbytes,
    277 	    p, busdmaflags);
    278 	if (error)
    279 		return (error);
    280 
    281 #ifdef ISADMA_DEBUG
    282 	__asm(".globl isa_dmastart_afterload ; isa_dmastart_afterload:");
    283 #endif
    284 
    285 	if (flags & DMAMODE_READ) {
    286 		bus_dmamap_sync(sc->sc_dmat, dmam, BUS_DMASYNC_PREREAD);
    287 		sc->sc_dmareads |= (1 << chan);
    288 	} else {
    289 		bus_dmamap_sync(sc->sc_dmat, dmam, BUS_DMASYNC_PREWRITE);
    290 		sc->sc_dmareads &= ~(1 << chan);
    291 	}
    292 
    293 	dmaaddr = dmam->dm_segs[0].ds_addr;
    294 
    295 #ifdef ISADMA_DEBUG
    296 	printf("     dmaaddr 0x%lx\n", dmaaddr);
    297 
    298 	__asm(".globl isa_dmastart_aftersync ; isa_dmastart_aftersync:");
    299 #endif
    300 
    301 	sc->sc_dmalength[chan] = nbytes;
    302 
    303 	isa_dmamask(sc, chan);
    304 	sc->sc_dmafinished &= ~(1 << chan);
    305 
    306 	if ((chan & 4) == 0) {
    307 		/* set dma channel mode */
    308 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h, DMA1_MODE,
    309 		    ochan | dmamode[flags]);
    310 
    311 		/* send start address */
    312 		waport = DMA1_CHN(ochan);
    313 		bus_space_write_1(sc->sc_iot, sc->sc_dmapgh,
    314 		    dmapageport[0][ochan], (dmaaddr >> 16) & 0xff);
    315 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h, waport,
    316 		    dmaaddr & 0xff);
    317 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h, waport,
    318 		    (dmaaddr >> 8) & 0xff);
    319 
    320 		/* send count */
    321 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h, waport + 1,
    322 		    (--nbytes) & 0xff);
    323 		bus_space_write_1(sc->sc_iot, sc->sc_dma1h, waport + 1,
    324 		    (nbytes >> 8) & 0xff);
    325 	} else {
    326 		/* set dma channel mode */
    327 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h, DMA2_MODE,
    328 		    ochan | dmamode[flags]);
    329 
    330 		/* send start address */
    331 		waport = DMA2_CHN(ochan);
    332 		bus_space_write_1(sc->sc_iot, sc->sc_dmapgh,
    333 		    dmapageport[1][ochan], (dmaaddr >> 16) & 0xff);
    334 		dmaaddr >>= 1;
    335 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h, waport,
    336 		    dmaaddr & 0xff);
    337 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h, waport,
    338 		    (dmaaddr >> 8) & 0xff);
    339 
    340 		/* send count */
    341 		nbytes >>= 1;
    342 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h, waport + 2,
    343 		    (--nbytes) & 0xff);
    344 		bus_space_write_1(sc->sc_iot, sc->sc_dma2h, waport + 2,
    345 		    (nbytes >> 8) & 0xff);
    346 	}
    347 
    348 	isa_dmaunmask(sc, chan);
    349 	return (0);
    350 
    351  lose:
    352 	panic("isa_dmastart");
    353 }
    354 
    355 void
    356 isa_dmaabort(isadev, chan)
    357 	struct device *isadev;
    358 	int chan;
    359 {
    360 	struct isa_softc *sc = (struct isa_softc *)isadev;
    361 
    362 	if (chan < 0 || chan > 7) {
    363 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    364 		panic("isa_dmaabort");
    365 	}
    366 
    367 	isa_dmamask(sc, chan);
    368 	bus_dmamap_unload(sc->sc_dmat, sc->sc_dmamaps[chan]);
    369 	sc->sc_dmareads &= ~(1 << chan);
    370 }
    371 
    372 bus_size_t
    373 isa_dmacount(isadev, chan)
    374 	struct device *isadev;
    375 	int chan;
    376 {
    377 	struct isa_softc *sc = (struct isa_softc *)isadev;
    378 	int waport;
    379 	bus_size_t nbytes;
    380 	int ochan = chan & 3;
    381 
    382 	if (chan < 0 || chan > 7) {
    383 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    384 		panic("isa_dmacount");
    385 	}
    386 
    387 	isa_dmamask(sc, chan);
    388 
    389 	/*
    390 	 * We have to shift the byte count by 1.  If we're in auto-initialize
    391 	 * mode, the count may have wrapped around to the initial value.  We
    392 	 * can't use the TC bit to check for this case, so instead we compare
    393 	 * against the original byte count.
    394 	 * If we're not in auto-initialize mode, then the count will wrap to
    395 	 * -1, so we also handle that case.
    396 	 */
    397 	if ((chan & 4) == 0) {
    398 		waport = DMA1_CHN(ochan);
    399 		nbytes = bus_space_read_1(sc->sc_iot, sc->sc_dma1h,
    400 		    waport + 1) + 1;
    401 		nbytes += bus_space_read_1(sc->sc_iot, sc->sc_dma1h,
    402 		    waport + 1) << 8;
    403 		nbytes &= 0xffff;
    404 	} else {
    405 		waport = DMA2_CHN(ochan);
    406 		nbytes = bus_space_read_1(sc->sc_iot, sc->sc_dma2h,
    407 		    waport + 2) + 1;
    408 		nbytes += bus_space_read_1(sc->sc_iot, sc->sc_dma2h,
    409 		    waport + 2) << 8;
    410 		nbytes <<= 1;
    411 		nbytes &= 0x1ffff;
    412 	}
    413 
    414 	if (nbytes == sc->sc_dmalength[chan])
    415 		nbytes = 0;
    416 
    417 	isa_dmaunmask(sc, chan);
    418 	return (nbytes);
    419 }
    420 
    421 int
    422 isa_dmafinished(isadev, chan)
    423 	struct device *isadev;
    424 	int chan;
    425 {
    426 	struct isa_softc *sc = (struct isa_softc *)isadev;
    427 
    428 	if (chan < 0 || chan > 7) {
    429 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    430 		panic("isa_dmafinished");
    431 	}
    432 
    433 	/* check that the terminal count was reached */
    434 	if ((chan & 4) == 0)
    435 		sc->sc_dmafinished |= bus_space_read_1(sc->sc_iot,
    436 		    sc->sc_dma1h, DMA1_SR) & 0x0f;
    437 	else
    438 		sc->sc_dmafinished |= (bus_space_read_1(sc->sc_iot,
    439 		    sc->sc_dma2h, DMA2_SR) & 0x0f) << 4;
    440 
    441 	return ((sc->sc_dmafinished & (1 << chan)) != 0);
    442 }
    443 
    444 void
    445 isa_dmadone(isadev, chan)
    446 	struct device *isadev;
    447 	int chan;
    448 {
    449 	struct isa_softc *sc = (struct isa_softc *)isadev;
    450 	bus_dmamap_t dmam;
    451 
    452 	if (chan < 0 || chan > 7) {
    453 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    454 		panic("isa_dmadone");
    455 	}
    456 
    457 	dmam = sc->sc_dmamaps[chan];
    458 
    459 	isa_dmamask(sc, chan);
    460 
    461 	if (isa_dmafinished(isadev, chan) == 0)
    462 		printf("%s: isa_dmadone: channel %d not finished\n",
    463 		    sc->sc_dev.dv_xname, chan);
    464 
    465 	bus_dmamap_sync(sc->sc_dmat, dmam,
    466 	    (sc->sc_dmareads & (1 << chan)) ? BUS_DMASYNC_POSTREAD :
    467 	    BUS_DMASYNC_POSTWRITE);
    468 
    469 	bus_dmamap_unload(sc->sc_dmat, dmam);
    470 	sc->sc_dmareads &= ~(1 << chan);
    471 }
    472 
    473 int
    474 isa_dmamem_alloc(isadev, chan, size, addrp, flags)
    475 	struct device *isadev;
    476 	int chan;
    477 	bus_size_t size;
    478 	bus_addr_t *addrp;
    479 	int flags;
    480 {
    481 	struct isa_softc *sc = (struct isa_softc *)isadev;
    482 	bus_dma_segment_t seg;
    483 	int error, boundary, rsegs;
    484 
    485 	if (chan < 0 || chan > 7) {
    486 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    487 		panic("isa_dmamem_alloc");
    488 	}
    489 
    490 	boundary = (chan & 4) ? (1 << 17) : (1 << 16);
    491 
    492 	size = round_page(size);
    493 
    494 	error = bus_dmamem_alloc(sc->sc_dmat, size, NBPG, boundary,
    495 	    &seg, 1, &rsegs, flags);
    496 	if (error)
    497 		return (error);
    498 
    499 	*addrp = seg.ds_addr;
    500 	return (0);
    501 }
    502 
    503 void
    504 isa_dmamem_free(isadev, chan, addr, size)
    505 	struct device *isadev;
    506 	int chan;
    507 	bus_addr_t addr;
    508 	bus_size_t size;
    509 {
    510 	struct isa_softc *sc = (struct isa_softc *)isadev;
    511 	bus_dma_segment_t seg;
    512 
    513 	if (chan < 0 || chan > 7) {
    514 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    515 		panic("isa_dmamem_free");
    516 	}
    517 
    518 	seg.ds_addr = addr;
    519 	seg.ds_len = size;
    520 
    521 	bus_dmamem_free(sc->sc_dmat, &seg, 1);
    522 }
    523 
    524 int
    525 isa_dmamem_map(isadev, chan, addr, size, kvap, flags)
    526 	struct device *isadev;
    527 	int chan;
    528 	bus_addr_t addr;
    529 	bus_size_t size;
    530 	caddr_t *kvap;
    531 	int flags;
    532 {
    533 	struct isa_softc *sc = (struct isa_softc *)isadev;
    534 	bus_dma_segment_t seg;
    535 
    536 	if (chan < 0 || chan > 7) {
    537 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    538 		panic("isa_dmamem_map");
    539 	}
    540 
    541 	seg.ds_addr = addr;
    542 	seg.ds_len = size;
    543 
    544 	return (bus_dmamem_map(sc->sc_dmat, &seg, 1, size, kvap, flags));
    545 }
    546 
    547 void
    548 isa_dmamem_unmap(isadev, chan, kva, size)
    549 	struct device *isadev;
    550 	int chan;
    551 	caddr_t kva;
    552 	size_t size;
    553 {
    554 	struct isa_softc *sc = (struct isa_softc *)isadev;
    555 
    556 	if (chan < 0 || chan > 7) {
    557 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    558 		panic("isa_dmamem_unmap");
    559 	}
    560 
    561 	bus_dmamem_unmap(sc->sc_dmat, kva, size);
    562 }
    563 
    564 int
    565 isa_dmamem_mmap(isadev, chan, addr, size, off, prot, flags)
    566 	struct device *isadev;
    567 	int chan;
    568 	bus_addr_t addr;
    569 	bus_size_t size;
    570 	int off, prot, flags;
    571 {
    572 	struct isa_softc *sc = (struct isa_softc *)isadev;
    573 	bus_dma_segment_t seg;
    574 
    575 	if (chan < 0 || chan > 7) {
    576 		printf("%s: bogus drq %d\n", sc->sc_dev.dv_xname, chan);
    577 		panic("isa_dmamem_mmap");
    578 	}
    579 
    580 	seg.ds_addr = addr;
    581 	seg.ds_len = size;
    582 
    583 	return (bus_dmamem_mmap(sc->sc_dmat, &seg, 1, off, prot, flags));
    584 }
    585 
    586 void *
    587 isa_malloc(isadev, chan, size, pool, flags)
    588 	struct device *isadev;
    589 	int chan;
    590 	size_t size;
    591 	int pool;
    592 	int flags;
    593 {
    594 	bus_addr_t addr;
    595 	caddr_t kva;
    596 	int bflags;
    597 	struct isa_mem *m;
    598 
    599 	bflags = flags & M_WAITOK ? BUS_DMA_WAITOK : BUS_DMA_NOWAIT;
    600 
    601 	if (isa_dmamem_alloc(isadev, chan, size, &addr, bflags))
    602 		return 0;
    603 	if (isa_dmamem_map(isadev, chan, addr, size, &kva, bflags)) {
    604 		isa_dmamem_free(isadev, chan, addr, size);
    605 		return 0;
    606 	}
    607 	m = malloc(sizeof(*m), pool, flags);
    608 	if (m == 0) {
    609 		isa_dmamem_unmap(isadev, chan, kva, size);
    610 		isa_dmamem_free(isadev, chan, addr, size);
    611 		return 0;
    612 	}
    613 	m->isadev = isadev;
    614 	m->chan = chan;
    615 	m->size = size;
    616 	m->addr = addr;
    617 	m->kva = kva;
    618 	m->next = isa_mem_head;
    619 	isa_mem_head = m;
    620 	return (void *)kva;
    621 }
    622 
    623 void
    624 isa_free(addr, pool)
    625 	void *addr;
    626 	int pool;
    627 {
    628 	struct isa_mem **mp, *m;
    629 	caddr_t kva = (caddr_t)addr;
    630 
    631 	for(mp = &isa_mem_head; *mp && (*mp)->kva != kva; mp = &(*mp)->next)
    632 		;
    633 	m = *mp;
    634 	if (!m) {
    635 		printf("isa_free: freeing unallocted memory\n");
    636 		return;
    637 	}
    638 	*mp = m->next;
    639 	isa_dmamem_unmap(m->isadev, m->chan, kva, m->size);
    640 	isa_dmamem_free(m->isadev, m->chan, m->addr, m->size);
    641 	free(m, pool);
    642 }
    643