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dma.c revision 1.22
      1 /*	$NetBSD: dma.c,v 1.22 1998/05/24 19:32:39 is Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1996, 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.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the NetBSD
     21  *	Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * Copyright (c) 1982, 1990, 1993
     41  *	The Regents of the University of California.  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 the University of
     54  *	California, Berkeley and its contributors.
     55  * 4. Neither the name of the University nor the names of its contributors
     56  *    may be used to endorse or promote products derived from this software
     57  *    without specific prior written permission.
     58  *
     59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     69  * SUCH DAMAGE.
     70  *
     71  *	@(#)dma.c	8.1 (Berkeley) 6/10/93
     72  */
     73 
     74 /*
     75  * DMA driver
     76  */
     77 
     78 #include <machine/hp300spu.h>	/* XXX param.h includes cpu.h */
     79 
     80 #include <sys/param.h>
     81 #include <sys/systm.h>
     82 #include <sys/time.h>
     83 #include <sys/kernel.h>
     84 #include <sys/proc.h>
     85 #include <sys/device.h>
     86 
     87 #include <machine/frame.h>
     88 #include <machine/cpu.h>
     89 #include <machine/intr.h>
     90 
     91 #include <hp300/dev/dmareg.h>
     92 #include <hp300/dev/dmavar.h>
     93 
     94 /*
     95  * The largest single request will be MAXPHYS bytes which will require
     96  * at most MAXPHYS/NBPG+1 chain elements to describe, i.e. if none of
     97  * the buffer pages are physically contiguous (MAXPHYS/NBPG) and the
     98  * buffer is not page aligned (+1).
     99  */
    100 #define	DMAMAXIO	(MAXPHYS/NBPG+1)
    101 
    102 struct dma_chain {
    103 	int	dc_count;
    104 	char	*dc_addr;
    105 };
    106 
    107 struct dma_channel {
    108 	struct	dmaqueue *dm_job;		/* current job */
    109 	struct	dmadevice *dm_hwaddr;		/* registers if DMA_C */
    110 	struct	dmaBdevice *dm_Bhwaddr;		/* registers if not DMA_C */
    111 	char	dm_flags;			/* misc. flags */
    112 	u_short	dm_cmd;				/* DMA controller command */
    113 	int	dm_cur;				/* current segment */
    114 	int	dm_last;			/* last segment */
    115 	struct	dma_chain dm_chain[DMAMAXIO];	/* all segments */
    116 };
    117 
    118 struct dma_softc {
    119 	struct	dmareg *sc_dmareg;		/* pointer to our hardware */
    120 	struct	dma_channel sc_chan[NDMACHAN];	/* 2 channels */
    121 	TAILQ_HEAD(, dmaqueue) sc_queue;	/* job queue */
    122 	char	sc_type;			/* A, B, or C */
    123 	int	sc_ipl;				/* our interrupt level */
    124 	void	*sc_ih;				/* interrupt cookie */
    125 } dma_softc;
    126 
    127 /* types */
    128 #define	DMA_B	0
    129 #define DMA_C	1
    130 
    131 /* flags */
    132 #define DMAF_PCFLUSH	0x01
    133 #define DMAF_VCFLUSH	0x02
    134 #define DMAF_NOINTR	0x04
    135 
    136 int	dmaintr __P((void *));
    137 
    138 #ifdef DEBUG
    139 int	dmadebug = 0;
    140 #define DDB_WORD	0x01	/* same as DMAGO_WORD */
    141 #define DDB_LWORD	0x02	/* same as DMAGO_LWORD */
    142 #define	DDB_FOLLOW	0x04
    143 #define DDB_IO		0x08
    144 
    145 void	dmatimeout __P((void *));
    146 int	dmatimo[NDMACHAN];
    147 
    148 long	dmahits[NDMACHAN];
    149 long	dmamisses[NDMACHAN];
    150 long	dmabyte[NDMACHAN];
    151 long	dmaword[NDMACHAN];
    152 long	dmalword[NDMACHAN];
    153 #endif
    154 
    155 /*
    156  * Initialize the DMA engine, called by dioattach()
    157  */
    158 void
    159 dmainit()
    160 {
    161 	struct dma_softc *sc = &dma_softc;
    162 	struct dmareg *dma;
    163 	struct dma_channel *dc;
    164 	int i;
    165 	char rev;
    166 
    167 	/* There's just one. */
    168 	sc->sc_dmareg = (struct dmareg *)DMA_BASE;
    169 	dma = sc->sc_dmareg;
    170 
    171 	/*
    172 	 * Determine the DMA type.  A DMA_A or DMA_B will fail the
    173 	 * following probe.
    174 	 *
    175 	 * XXX Don't know how to easily differentiate the A and B cards,
    176 	 * so we just hope nobody has an A card (A cards will work if
    177 	 * splbio works out to ipl 3).
    178 	 */
    179 	if (badbaddr((char *)&dma->dma_id[2])) {
    180 		rev = 'B';
    181 #if !defined(HP320)
    182 		panic("dmainit: DMA card requires hp320 support");
    183 #endif
    184 	} else
    185 		rev = dma->dma_id[2];
    186 
    187 	sc->sc_type = (rev == 'B') ? DMA_B : DMA_C;
    188 
    189 	TAILQ_INIT(&sc->sc_queue);
    190 
    191 	for (i = 0; i < NDMACHAN; i++) {
    192 		dc = &sc->sc_chan[i];
    193 		dc->dm_job = NULL;
    194 		switch (i) {
    195 		case 0:
    196 			dc->dm_hwaddr = &dma->dma_chan0;
    197 			dc->dm_Bhwaddr = &dma->dma_Bchan0;
    198 			break;
    199 
    200 		case 1:
    201 			dc->dm_hwaddr = &dma->dma_chan1;
    202 			dc->dm_Bhwaddr = &dma->dma_Bchan1;
    203 			break;
    204 
    205 		default:
    206 			panic("dmainit: more than 2 channels?");
    207 			/* NOTREACHED */
    208 		}
    209 	}
    210 
    211 #ifdef DEBUG
    212 	/* make sure timeout is really not needed */
    213 	timeout(dmatimeout, sc, 30 * hz);
    214 #endif
    215 
    216 	printf("98620%c, 2 channels, %d bit DMA\n",
    217 	    rev, (rev == 'B') ? 16 : 32);
    218 
    219 	/*
    220 	 * Defer hooking up our interrupt until the first
    221 	 * DMA-using controller has hooked up theirs.
    222 	 */
    223 	sc->sc_ih = NULL;
    224 }
    225 
    226 /*
    227  * Compute the ipl and (re)establish the interrupt handler
    228  * for the DMA controller.
    229  */
    230 void
    231 dmacomputeipl()
    232 {
    233 	struct dma_softc *sc = &dma_softc;
    234 
    235 	if (sc->sc_ih != NULL)
    236 		intr_disestablish(sc->sc_ih);
    237 
    238 	/*
    239 	 * Our interrupt level must be as high as the highest
    240 	 * device using DMA (i.e. splbio).
    241 	 */
    242 	sc->sc_ipl = PSLTOIPL(hp300_bioipl);
    243 	sc->sc_ih = intr_establish(dmaintr, sc, sc->sc_ipl, IPL_BIO);
    244 }
    245 
    246 int
    247 dmareq(dq)
    248 	struct dmaqueue *dq;
    249 {
    250 	struct dma_softc *sc = &dma_softc;
    251 	int i, chan, s;
    252 
    253 #if 1
    254 	s = splhigh();	/* XXXthorpej */
    255 #else
    256 	s = splbio();
    257 #endif
    258 
    259 	chan = dq->dq_chan;
    260 	for (i = NDMACHAN - 1; i >= 0; i--) {
    261 		/*
    262 		 * Can we use this channel?
    263 		 */
    264 		if ((chan & (1 << i)) == 0)
    265 			continue;
    266 
    267 		/*
    268 		 * We can use it; is it busy?
    269 		 */
    270 		if (sc->sc_chan[i].dm_job != NULL)
    271 			continue;
    272 
    273 		/*
    274 		 * Not busy; give the caller this channel.
    275 		 */
    276 		sc->sc_chan[i].dm_job = dq;
    277 		dq->dq_chan = i;
    278 		splx(s);
    279 		return (1);
    280 	}
    281 
    282 	/*
    283 	 * Couldn't get a channel now; put this in the queue.
    284 	 */
    285 	TAILQ_INSERT_TAIL(&sc->sc_queue, dq, dq_list);
    286 	splx(s);
    287 	return (0);
    288 }
    289 
    290 void
    291 dmafree(dq)
    292 	struct dmaqueue *dq;
    293 {
    294 	int unit = dq->dq_chan;
    295 	struct dma_softc *sc = &dma_softc;
    296 	struct dma_channel *dc = &sc->sc_chan[unit];
    297 	struct dmaqueue *dn;
    298 	int chan, s;
    299 
    300 #if 1
    301 	s = splhigh();	/* XXXthorpej */
    302 #else
    303 	s = splbio();
    304 #endif
    305 
    306 #ifdef DEBUG
    307 	dmatimo[unit] = 0;
    308 #endif
    309 
    310 	DMA_CLEAR(dc);
    311 
    312 #if defined(CACHE_HAVE_PAC) || defined(M68040)
    313 	/*
    314 	 * XXX we may not always go thru the flush code in dmastop()
    315 	 */
    316 	if (dc->dm_flags & DMAF_PCFLUSH) {
    317 		PCIA();
    318 		dc->dm_flags &= ~DMAF_PCFLUSH;
    319 	}
    320 #endif
    321 
    322 #if defined(CACHE_HAVE_VAC)
    323 	if (dc->dm_flags & DMAF_VCFLUSH) {
    324 		/*
    325 		 * 320/350s have VACs that may also need flushing.
    326 		 * In our case we only flush the supervisor side
    327 		 * because we know that if we are DMAing to user
    328 		 * space, the physical pages will also be mapped
    329 		 * in kernel space (via vmapbuf) and hence cache-
    330 		 * inhibited by the pmap module due to the multiple
    331 		 * mapping.
    332 		 */
    333 		DCIS();
    334 		dc->dm_flags &= ~DMAF_VCFLUSH;
    335 	}
    336 #endif
    337 
    338 	/*
    339 	 * Channel is now free.  Look for another job to run on this
    340 	 * channel.
    341 	 */
    342 	dc->dm_job = NULL;
    343 	chan = 1 << unit;
    344 	for (dn = sc->sc_queue.tqh_first; dn != NULL;
    345 	    dn = dn->dq_list.tqe_next) {
    346 		if (dn->dq_chan & chan) {
    347 			/* Found one... */
    348 			TAILQ_REMOVE(&sc->sc_queue, dn, dq_list);
    349 			dc->dm_job = dn;
    350 			dn->dq_chan = dq->dq_chan;
    351 			splx(s);
    352 
    353 			/* Start the initiator. */
    354 			(*dn->dq_start)(dn->dq_softc);
    355 			return;
    356 		}
    357 	}
    358 	splx(s);
    359 }
    360 
    361 void
    362 dmago(unit, addr, count, flags)
    363 	int unit;
    364 	char *addr;
    365 	int count;
    366 	int flags;
    367 {
    368 	struct dma_softc *sc = &dma_softc;
    369 	struct dma_channel *dc = &sc->sc_chan[unit];
    370 	char *dmaend = NULL;
    371 	int seg, tcount;
    372 
    373 	if (count > MAXPHYS)
    374 		panic("dmago: count > MAXPHYS");
    375 
    376 #if defined(HP320)
    377 	if (sc->sc_type == DMA_B && (flags & DMAGO_LWORD))
    378 		panic("dmago: no can do 32-bit DMA");
    379 #endif
    380 
    381 #ifdef DEBUG
    382 	if (dmadebug & DDB_FOLLOW)
    383 		printf("dmago(%d, %p, %x, %x)\n",
    384 		       unit, addr, count, flags);
    385 	if (flags & DMAGO_LWORD)
    386 		dmalword[unit]++;
    387 	else if (flags & DMAGO_WORD)
    388 		dmaword[unit]++;
    389 	else
    390 		dmabyte[unit]++;
    391 #endif
    392 	/*
    393 	 * Build the DMA chain
    394 	 */
    395 	for (seg = 0; count > 0; seg++) {
    396 		dc->dm_chain[seg].dc_addr = (char *) kvtop(addr);
    397 #if defined(M68040)
    398 		/*
    399 		 * Push back dirty cache lines
    400 		 */
    401 		if (mmutype == MMU_68040)
    402 			DCFP((vm_offset_t)dc->dm_chain[seg].dc_addr);
    403 #endif
    404 		if (count < (tcount = NBPG - ((int)addr & PGOFSET)))
    405 			tcount = count;
    406 		dc->dm_chain[seg].dc_count = tcount;
    407 		addr += tcount;
    408 		count -= tcount;
    409 		if (flags & DMAGO_LWORD)
    410 			tcount >>= 2;
    411 		else if (flags & DMAGO_WORD)
    412 			tcount >>= 1;
    413 
    414 		/*
    415 		 * Try to compact the DMA transfer if the pages are adjacent.
    416 		 * Note: this will never happen on the first iteration.
    417 		 */
    418 		if (dc->dm_chain[seg].dc_addr == dmaend
    419 #if defined(HP320)
    420 		    /* only 16-bit count on 98620B */
    421 		    && (sc->sc_type != DMA_B ||
    422 			dc->dm_chain[seg - 1].dc_count + tcount <= 65536)
    423 #endif
    424 		) {
    425 #ifdef DEBUG
    426 			dmahits[unit]++;
    427 #endif
    428 			dmaend += dc->dm_chain[seg].dc_count;
    429 			dc->dm_chain[--seg].dc_count += tcount;
    430 		} else {
    431 #ifdef DEBUG
    432 			dmamisses[unit]++;
    433 #endif
    434 			dmaend = dc->dm_chain[seg].dc_addr +
    435 			    dc->dm_chain[seg].dc_count;
    436 			dc->dm_chain[seg].dc_count = tcount;
    437 		}
    438 	}
    439 	dc->dm_cur = 0;
    440 	dc->dm_last = --seg;
    441 	dc->dm_flags = 0;
    442 	/*
    443 	 * Set up the command word based on flags
    444 	 */
    445 	dc->dm_cmd = DMA_ENAB | DMA_IPL(sc->sc_ipl) | DMA_START;
    446 	if ((flags & DMAGO_READ) == 0)
    447 		dc->dm_cmd |= DMA_WRT;
    448 	if (flags & DMAGO_LWORD)
    449 		dc->dm_cmd |= DMA_LWORD;
    450 	else if (flags & DMAGO_WORD)
    451 		dc->dm_cmd |= DMA_WORD;
    452 	if (flags & DMAGO_PRI)
    453 		dc->dm_cmd |= DMA_PRI;
    454 
    455 #if defined(M68040)
    456 	/*
    457 	 * On the 68040 we need to flush (push) the data cache before a
    458 	 * DMA (already done above) and flush again after DMA completes.
    459 	 * In theory we should only need to flush prior to a write DMA
    460 	 * and purge after a read DMA but if the entire page is not
    461 	 * involved in the DMA we might purge some valid data.
    462 	 */
    463 	if (mmutype == MMU_68040 && (flags & DMAGO_READ))
    464 		dc->dm_flags |= DMAF_PCFLUSH;
    465 #endif
    466 
    467 #if defined(CACHE_HAVE_PAC)
    468 	/*
    469 	 * Remember if we need to flush external physical cache when
    470 	 * DMA is done.  We only do this if we are reading (writing memory).
    471 	 */
    472 	if (ectype == EC_PHYS && (flags & DMAGO_READ))
    473 		dc->dm_flags |= DMAF_PCFLUSH;
    474 #endif
    475 
    476 #if defined(CACHE_HAVE_VAC)
    477 	if (ectype == EC_VIRT && (flags & DMAGO_READ))
    478 		dc->dm_flags |= DMAF_VCFLUSH;
    479 #endif
    480 
    481 	/*
    482 	 * Remember if we can skip the dma completion interrupt on
    483 	 * the last segment in the chain.
    484 	 */
    485 	if (flags & DMAGO_NOINT) {
    486 		if (dc->dm_cur == dc->dm_last)
    487 			dc->dm_cmd &= ~DMA_ENAB;
    488 		else
    489 			dc->dm_flags |= DMAF_NOINTR;
    490 	}
    491 #ifdef DEBUG
    492 	if (dmadebug & DDB_IO) {
    493 		if (((dmadebug&DDB_WORD) && (dc->dm_cmd&DMA_WORD)) ||
    494 		    ((dmadebug&DDB_LWORD) && (dc->dm_cmd&DMA_LWORD))) {
    495 			printf("dmago: cmd %x, flags %x\n",
    496 			       dc->dm_cmd, dc->dm_flags);
    497 			for (seg = 0; seg <= dc->dm_last; seg++)
    498 				printf("  %d: %d@%p\n", seg,
    499 				    dc->dm_chain[seg].dc_count,
    500 				    dc->dm_chain[seg].dc_addr);
    501 		}
    502 	}
    503 	dmatimo[unit] = 1;
    504 #endif
    505 	DMA_ARM(sc, dc);
    506 }
    507 
    508 void
    509 dmastop(unit)
    510 	int unit;
    511 {
    512 	struct dma_softc *sc = &dma_softc;
    513 	struct dma_channel *dc = &sc->sc_chan[unit];
    514 
    515 #ifdef DEBUG
    516 	if (dmadebug & DDB_FOLLOW)
    517 		printf("dmastop(%d)\n", unit);
    518 	dmatimo[unit] = 0;
    519 #endif
    520 	DMA_CLEAR(dc);
    521 
    522 #if defined(CACHE_HAVE_PAC) || defined(M68040)
    523 	if (dc->dm_flags & DMAF_PCFLUSH) {
    524 		PCIA();
    525 		dc->dm_flags &= ~DMAF_PCFLUSH;
    526 	}
    527 #endif
    528 
    529 #if defined(CACHE_HAVE_VAC)
    530 	if (dc->dm_flags & DMAF_VCFLUSH) {
    531 		/*
    532 		 * 320/350s have VACs that may also need flushing.
    533 		 * In our case we only flush the supervisor side
    534 		 * because we know that if we are DMAing to user
    535 		 * space, the physical pages will also be mapped
    536 		 * in kernel space (via vmapbuf) and hence cache-
    537 		 * inhibited by the pmap module due to the multiple
    538 		 * mapping.
    539 		 */
    540 		DCIS();
    541 		dc->dm_flags &= ~DMAF_VCFLUSH;
    542 	}
    543 #endif
    544 
    545 	/*
    546 	 * We may get this interrupt after a device service routine
    547 	 * has freed the dma channel.  So, ignore the intr if there's
    548 	 * nothing on the queue.
    549 	 */
    550 	if (dc->dm_job != NULL)
    551 		(*dc->dm_job->dq_done)(dc->dm_job->dq_softc);
    552 }
    553 
    554 int
    555 dmaintr(arg)
    556 	void *arg;
    557 {
    558 	struct dma_softc *sc = arg;
    559 	struct dma_channel *dc;
    560 	int i, stat;
    561 	int found = 0;
    562 
    563 #ifdef DEBUG
    564 	if (dmadebug & DDB_FOLLOW)
    565 		printf("dmaintr\n");
    566 #endif
    567 	for (i = 0; i < NDMACHAN; i++) {
    568 		dc = &sc->sc_chan[i];
    569 		stat = DMA_STAT(dc);
    570 		if ((stat & DMA_INTR) == 0)
    571 			continue;
    572 		found++;
    573 #ifdef DEBUG
    574 		if (dmadebug & DDB_IO) {
    575 			if (((dmadebug&DDB_WORD) && (dc->dm_cmd&DMA_WORD)) ||
    576 			    ((dmadebug&DDB_LWORD) && (dc->dm_cmd&DMA_LWORD)))
    577 			  printf("dmaintr: flags %x unit %d stat %x next %d\n",
    578 			   dc->dm_flags, i, stat, dc->dm_cur + 1);
    579 		}
    580 		if (stat & DMA_ARMED)
    581 			printf("dma channel %d: intr when armed\n", i);
    582 #endif
    583 		/*
    584 		 * Load the next segemnt, or finish up if we're done.
    585 		 */
    586 		dc->dm_cur++;
    587 		if (dc->dm_cur <= dc->dm_last) {
    588 #ifdef DEBUG
    589 			dmatimo[i] = 1;
    590 #endif
    591 			/*
    592 			 * If we're the last segment, disable the
    593 			 * completion interrupt, if necessary.
    594 			 */
    595 			if (dc->dm_cur == dc->dm_last &&
    596 			    (dc->dm_flags & DMAF_NOINTR))
    597 				dc->dm_cmd &= ~DMA_ENAB;
    598 			DMA_CLEAR(dc);
    599 			DMA_ARM(sc, dc);
    600 		} else
    601 			dmastop(i);
    602 	}
    603 	return(found);
    604 }
    605 
    606 #ifdef DEBUG
    607 void
    608 dmatimeout(arg)
    609 	void *arg;
    610 {
    611 	int i, s;
    612 	struct dma_softc *sc = arg;
    613 
    614 	for (i = 0; i < NDMACHAN; i++) {
    615 		s = splbio();
    616 		if (dmatimo[i]) {
    617 			if (dmatimo[i] > 1)
    618 				printf("dma channel %d timeout #%d\n",
    619 				    i, dmatimo[i]-1);
    620 			dmatimo[i]++;
    621 		}
    622 		splx(s);
    623 	}
    624 	timeout(dmatimeout, sc, 30 * hz);
    625 }
    626 #endif
    627