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isa_dma.c revision 1.6.44.2
      1 /*	$NetBSD: isa_dma.c,v 1.6.44.2 2009/05/04 08:10:47 yamt Exp $	*/
      2 
      3 #define ISA_DMA_STATS
      4 
      5 /*-
      6  * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
      7  * All rights reserved.
      8  *
      9  * This code is derived from software contributed to The NetBSD Foundation
     10  * by Charles M. Hannum and by Jason R. Thorpe of the Numerical Aerospace
     11  * Simulation Facility, NASA Ames Research Center.
     12  *
     13  * Redistribution and use in source and binary forms, with or without
     14  * modification, are permitted provided that the following conditions
     15  * are met:
     16  * 1. Redistributions of source code must retain the above copyright
     17  *    notice, this list of conditions and the following disclaimer.
     18  * 2. Redistributions in binary form must reproduce the above copyright
     19  *    notice, this list of conditions and the following disclaimer in the
     20  *    documentation and/or other materials provided with the distribution.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     24  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     25  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     26  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     32  * POSSIBILITY OF SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 __KERNEL_RCSID(0, "$NetBSD: isa_dma.c,v 1.6.44.2 2009/05/04 08:10:47 yamt Exp $");
     37 
     38 #include <sys/param.h>
     39 #include <sys/systm.h>
     40 #include <sys/kernel.h>
     41 #include <sys/syslog.h>
     42 #include <sys/device.h>
     43 #include <sys/malloc.h>
     44 #include <sys/proc.h>
     45 #include <sys/mbuf.h>
     46 
     47 #define _ATARI_BUS_DMA_PRIVATE
     48 #include <machine/bus.h>
     49 
     50 #include <dev/isa/isareg.h>
     51 #include <dev/isa/isavar.h>
     52 
     53 #include <uvm/uvm_extern.h>
     54 
     55 extern	paddr_t avail_end;
     56 
     57 /*
     58  * Cookie used by ISA dma.  A pointer to one of these it stashed in
     59  * the DMA map.
     60  */
     61 struct atari_isa_dma_cookie {
     62 	int	id_flags;		/* flags; see below */
     63 
     64 	/*
     65 	 * Information about the original buffer used during
     66 	 * DMA map syncs.  Note that origibuflen is only used
     67 	 * for ID_BUFTYPE_LINEAR.
     68 	 */
     69 	void	*id_origbuf;		/* pointer to orig buffer if
     70 					   bouncing */
     71 	bus_size_t id_origbuflen;	/* ...and size */
     72 	int	id_buftype;		/* type of buffer */
     73 
     74 	void	*id_bouncebuf;		/* pointer to the bounce buffer */
     75 	bus_size_t id_bouncebuflen;	/* ...and size */
     76 	int	id_nbouncesegs;		/* number of valid bounce segs */
     77 	bus_dma_segment_t id_bouncesegs[0]; /* array of bounce buffer
     78 					       physical memory segments */
     79 };
     80 
     81 /* id_flags */
     82 #define	ID_MIGHT_NEED_BOUNCE	0x01	/* map could need bounce buffers */
     83 #define	ID_HAS_BOUNCE		0x02	/* map currently has bounce buffers */
     84 #define	ID_IS_BOUNCING		0x04	/* map is bouncing current xfer */
     85 
     86 /* id_buftype */
     87 #define	ID_BUFTYPE_INVALID	0
     88 #define	ID_BUFTYPE_LINEAR	1
     89 #define	ID_BUFTYPE_MBUF		2
     90 #define	ID_BUFTYPE_UIO		3
     91 #define	ID_BUFTYPE_RAW		4
     92 
     93 int	_isa_bus_dmamap_create(bus_dma_tag_t, bus_size_t, int,
     94 	    bus_size_t, bus_size_t, int, bus_dmamap_t *);
     95 void	_isa_bus_dmamap_destroy(bus_dma_tag_t, bus_dmamap_t);
     96 int	_isa_bus_dmamap_load(bus_dma_tag_t, bus_dmamap_t, void *,
     97 	    bus_size_t, struct proc *, int);
     98 int	_isa_bus_dmamap_load_mbuf(bus_dma_tag_t, bus_dmamap_t,
     99 	    struct mbuf *, int);
    100 int	_isa_bus_dmamap_load_uio(bus_dma_tag_t, bus_dmamap_t,
    101 	    struct uio *, int);
    102 int	_isa_bus_dmamap_load_raw(bus_dma_tag_t, bus_dmamap_t,
    103 	    bus_dma_segment_t *, int, bus_size_t, int);
    104 void	_isa_bus_dmamap_unload(bus_dma_tag_t, bus_dmamap_t);
    105 void	_isa_bus_dmamap_sync(bus_dma_tag_t, bus_dmamap_t,
    106 	    bus_addr_t, bus_size_t, int);
    107 
    108 int	_isa_bus_dmamem_alloc(bus_dma_tag_t, bus_size_t, bus_size_t,
    109 	    bus_size_t, bus_dma_segment_t *, int, int *, int);
    110 
    111 int	_isa_dma_alloc_bouncebuf(bus_dma_tag_t, bus_dmamap_t,
    112 	    bus_size_t, int);
    113 void	_isa_dma_free_bouncebuf(bus_dma_tag_t, bus_dmamap_t);
    114 
    115 /*
    116  * Entry points for ISA DMA.  These are mostly wrappers around
    117  * the generic functions that understand how to deal with bounce
    118  * buffers, if necessary.
    119  */
    120 struct atari_bus_dma_tag isa_bus_dma_tag = {
    121 	ISA_DMA_BOUNCE_THRESHOLD,
    122 	0,
    123 	_isa_bus_dmamap_create,
    124 	_isa_bus_dmamap_destroy,
    125 	_isa_bus_dmamap_load,
    126 	_isa_bus_dmamap_load_mbuf,
    127 	_isa_bus_dmamap_load_uio,
    128 	_isa_bus_dmamap_load_raw,
    129 	_isa_bus_dmamap_unload,
    130 	_isa_bus_dmamap_sync,
    131 };
    132 
    133 /**********************************************************************
    134  * bus.h dma interface entry points
    135  **********************************************************************/
    136 
    137 #ifdef ISA_DMA_STATS
    138 #define	STAT_INCR(v)	(v)++
    139 #define	STAT_DECR(v)	do { \
    140 		if ((v) == 0) \
    141 			printf("%s:%d -- Already 0!\n", __FILE__, __LINE__); \
    142 		else \
    143 			(v)--; \
    144 		} while (0)
    145 u_long	isa_dma_stats_loads;
    146 u_long	isa_dma_stats_bounces;
    147 u_long	isa_dma_stats_nbouncebufs;
    148 #else
    149 #define	STAT_INCR(v)
    150 #define	STAT_DECR(v)
    151 #endif
    152 
    153 /*
    154  * Create an ISA DMA map.
    155  */
    156 int
    157 _isa_bus_dmamap_create(bus_dma_tag_t t, bus_size_t size, int nsegments, bus_size_t maxsegsz, bus_size_t boundary, int flags, bus_dmamap_t *dmamp)
    158 {
    159 	struct atari_isa_dma_cookie *cookie;
    160 	bus_dmamap_t map;
    161 	int error, cookieflags;
    162 	void *cookiestore;
    163 	size_t cookiesize;
    164 
    165 	/* Call common function to create the basic map. */
    166 	error = _bus_dmamap_create(t, size, nsegments, maxsegsz, boundary,
    167 	    flags, dmamp);
    168 	if (error)
    169 		return (error);
    170 
    171 	map = *dmamp;
    172 	map->_dm_cookie = NULL;
    173 
    174 	cookiesize = sizeof(struct atari_isa_dma_cookie);
    175 
    176 	/*
    177 	 * ISA only has 24-bits of address space.  This means
    178 	 * we can't DMA to pages over 16M.  In order to DMA to
    179 	 * arbitrary buffers, we use "bounce buffers" - pages
    180 	 * in memory below the 16M boundary.  On DMA reads,
    181 	 * DMA happens to the bounce buffers, and is copied into
    182 	 * the caller's buffer.  On writes, data is copied into
    183 	 * but bounce buffer, and the DMA happens from those
    184 	 * pages.  To software using the DMA mapping interface,
    185 	 * this looks simply like a data cache.
    186 	 *
    187 	 * If we have more than 16M of RAM in the system, we may
    188 	 * need bounce buffers.  We check and remember that here.
    189 	 *
    190 	 * There are exceptions, however.  VLB devices can do
    191 	 * 32-bit DMA, and indicate that here.
    192 	 *
    193 	 * ...or, there is an opposite case.  The most segments
    194 	 * a transfer will require is (maxxfer / PAGE_SIZE) + 1.  If
    195 	 * the caller can't handle that many segments (e.g. the
    196 	 * ISA DMA controller), we may have to bounce it as well.
    197 	 */
    198 	if (avail_end <= t->_bounce_thresh ||
    199 	    (flags & ISABUS_DMA_32BIT) != 0) {
    200 		/* Bouncing not necessary due to memory size. */
    201 		map->_dm_bounce_thresh = 0;
    202 	}
    203 	cookieflags = 0;
    204 	if (map->_dm_bounce_thresh != 0 ||
    205 	    ((map->_dm_size / PAGE_SIZE) + 1) > map->_dm_segcnt) {
    206 		cookieflags |= ID_MIGHT_NEED_BOUNCE;
    207 		cookiesize += (sizeof(bus_dma_segment_t) * map->_dm_segcnt);
    208 	}
    209 
    210 	/*
    211 	 * Allocate our cookie.
    212 	 */
    213 	if ((cookiestore = malloc(cookiesize, M_DMAMAP,
    214 	    (flags & BUS_DMA_NOWAIT) ? M_NOWAIT : M_WAITOK)) == NULL) {
    215 		error = ENOMEM;
    216 		goto out;
    217 	}
    218 	memset(cookiestore, 0, cookiesize);
    219 	cookie = (struct atari_isa_dma_cookie *)cookiestore;
    220 	cookie->id_flags = cookieflags;
    221 	map->_dm_cookie = cookie;
    222 
    223 	if (cookieflags & ID_MIGHT_NEED_BOUNCE) {
    224 		/*
    225 		 * Allocate the bounce pages now if the caller
    226 		 * wishes us to do so.
    227 		 */
    228 		if ((flags & BUS_DMA_ALLOCNOW) == 0)
    229 			goto out;
    230 
    231 		error = _isa_dma_alloc_bouncebuf(t, map, size, flags);
    232 	}
    233 
    234  out:
    235 	if (error) {
    236 		if (map->_dm_cookie != NULL)
    237 			free(map->_dm_cookie, M_DMAMAP);
    238 		_bus_dmamap_destroy(t, map);
    239 	}
    240 	return (error);
    241 }
    242 
    243 /*
    244  * Destroy an ISA DMA map.
    245  */
    246 void
    247 _isa_bus_dmamap_destroy(bus_dma_tag_t t, bus_dmamap_t map)
    248 {
    249 	struct atari_isa_dma_cookie *cookie = map->_dm_cookie;
    250 
    251 	/*
    252 	 * Free any bounce pages this map might hold.
    253 	 */
    254 	if (cookie->id_flags & ID_HAS_BOUNCE)
    255 		_isa_dma_free_bouncebuf(t, map);
    256 
    257 	free(cookie, M_DMAMAP);
    258 	_bus_dmamap_destroy(t, map);
    259 }
    260 
    261 /*
    262  * Load an ISA DMA map with a linear buffer.
    263  */
    264 int
    265 _isa_bus_dmamap_load(t, map, buf, buflen, p, flags)
    266 	bus_dma_tag_t t;
    267 	bus_dmamap_t map;
    268 	void *buf;
    269 	bus_size_t buflen;
    270 	struct proc *p;
    271 	int flags;
    272 {
    273 	struct atari_isa_dma_cookie *cookie = map->_dm_cookie;
    274 	int error;
    275 
    276 	STAT_INCR(isa_dma_stats_loads);
    277 
    278 	/*
    279 	 * Make sure that on error condition we return "no valid mappings."
    280 	 */
    281 	map->dm_mapsize = 0;
    282 	map->dm_nsegs = 0;
    283 
    284 	/*
    285 	 * Try to load the map the normal way.  If this errors out,
    286 	 * and we can bounce, we will.
    287 	 */
    288 	error = _bus_dmamap_load(t, map, buf, buflen, p, flags);
    289 	if (error == 0 ||
    290 	    (error != 0 && (cookie->id_flags & ID_MIGHT_NEED_BOUNCE) == 0))
    291 		return (error);
    292 
    293 	/*
    294 	 * First attempt failed; bounce it.
    295 	 */
    296 
    297 	STAT_INCR(isa_dma_stats_bounces);
    298 
    299 	/*
    300 	 * Allocate bounce pages, if necessary.
    301 	 */
    302 	if ((cookie->id_flags & ID_HAS_BOUNCE) == 0) {
    303 		error = _isa_dma_alloc_bouncebuf(t, map, buflen, flags);
    304 		if (error)
    305 			return (error);
    306 	}
    307 
    308 	/*
    309 	 * Cache a pointer to the caller's buffer and load the DMA map
    310 	 * with the bounce buffer.
    311 	 */
    312 	cookie->id_origbuf = buf;
    313 	cookie->id_origbuflen = buflen;
    314 	cookie->id_buftype = ID_BUFTYPE_LINEAR;
    315 	error = _bus_dmamap_load(t, map, cookie->id_bouncebuf, buflen,
    316 	    p, flags);
    317 	if (error) {
    318 		/*
    319 		 * Free the bounce pages, unless our resources
    320 		 * are reserved for our exclusive use.
    321 		 */
    322 		if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
    323 			_isa_dma_free_bouncebuf(t, map);
    324 		return (error);
    325 	}
    326 
    327 	/* ...so _isa_bus_dmamap_sync() knows we're bouncing */
    328 	cookie->id_flags |= ID_IS_BOUNCING;
    329 	return (0);
    330 }
    331 
    332 /*
    333  * Like _isa_bus_dmamap_load(), but for mbufs.
    334  */
    335 int
    336 _isa_bus_dmamap_load_mbuf(t, map, m0, flags)
    337 	bus_dma_tag_t t;
    338 	bus_dmamap_t map;
    339 	struct mbuf *m0;
    340 	int flags;
    341 {
    342 	struct atari_isa_dma_cookie *cookie = map->_dm_cookie;
    343 	int error;
    344 
    345 	/*
    346 	 * Make sure on error condition we return "no valid mappings."
    347 	 */
    348 	map->dm_mapsize = 0;
    349 	map->dm_nsegs = 0;
    350 
    351 #ifdef DIAGNOSTIC
    352 	if ((m0->m_flags & M_PKTHDR) == 0)
    353 		panic("_isa_bus_dmamap_load_mbuf: no packet header");
    354 #endif
    355 
    356 	if (m0->m_pkthdr.len > map->_dm_size)
    357 		return (EINVAL);
    358 
    359 	/*
    360 	 * Try to load the map the normal way.  If this errors out,
    361 	 * and we can bounce, we will.
    362 	 */
    363 	error = _bus_dmamap_load_mbuf(t, map, m0, flags);
    364 	if (error == 0 ||
    365 	    (error != 0 && (cookie->id_flags & ID_MIGHT_NEED_BOUNCE) == 0))
    366 		return (error);
    367 
    368 	/*
    369 	 * First attempt failed; bounce it.
    370 	 */
    371 
    372 	STAT_INCR(isa_dma_stats_bounces);
    373 
    374 	/*
    375 	 * Allocate bounce pages, if necessary.
    376 	 */
    377 	if ((cookie->id_flags & ID_HAS_BOUNCE) == 0) {
    378 		error = _isa_dma_alloc_bouncebuf(t, map, m0->m_pkthdr.len,
    379 		    flags);
    380 		if (error)
    381 			return (error);
    382 	}
    383 
    384 	/*
    385 	 * Cache a pointer to the caller's buffer and load the DMA map
    386 	 * with the bounce buffer.
    387 	 */
    388 	cookie->id_origbuf = m0;
    389 	cookie->id_origbuflen = m0->m_pkthdr.len;	/* not really used */
    390 	cookie->id_buftype = ID_BUFTYPE_MBUF;
    391 	error = _bus_dmamap_load(t, map, cookie->id_bouncebuf,
    392 	    m0->m_pkthdr.len, NULL, flags);
    393 	if (error) {
    394 		/*
    395 		 * Free the bounce pages, unless our resources
    396 		 * are reserved for our exclusive use.
    397 		 */
    398 		if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
    399 			_isa_dma_free_bouncebuf(t, map);
    400 		return (error);
    401 	}
    402 
    403 	/* ...so _isa_bus_dmamap_sync() knows we're bouncing */
    404 	cookie->id_flags |= ID_IS_BOUNCING;
    405 	return (0);
    406 }
    407 
    408 /*
    409  * Like _isa_bus_dmamap_load(), but for uios.
    410  */
    411 int
    412 _isa_bus_dmamap_load_uio(bus_dma_tag_t t, bus_dmamap_t map, struct uio *uio, int flags)
    413 {
    414 
    415 	panic("_isa_bus_dmamap_load_uio: not implemented");
    416 }
    417 
    418 /*
    419  * Like _isa_bus_dmamap_load(), but for raw memory allocated with
    420  * bus_dmamem_alloc().
    421  */
    422 int
    423 _isa_bus_dmamap_load_raw(bus_dma_tag_t t, bus_dmamap_t map, bus_dma_segment_t *segs, int nsegs, bus_size_t size, int flags)
    424 {
    425 
    426 	panic("_isa_bus_dmamap_load_raw: not implemented");
    427 }
    428 
    429 /*
    430  * Unload an ISA DMA map.
    431  */
    432 void
    433 _isa_bus_dmamap_unload(bus_dma_tag_t t, bus_dmamap_t map)
    434 {
    435 	struct atari_isa_dma_cookie *cookie = map->_dm_cookie;
    436 
    437 	/*
    438 	 * If we have bounce pages, free them, unless they're
    439 	 * reserved for our exclusive use.
    440 	 */
    441 	if ((cookie->id_flags & ID_HAS_BOUNCE) &&
    442 	    (map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
    443 		_isa_dma_free_bouncebuf(t, map);
    444 
    445 	cookie->id_flags &= ~ID_IS_BOUNCING;
    446 	cookie->id_buftype = ID_BUFTYPE_INVALID;
    447 
    448 	/*
    449 	 * Do the generic bits of the unload.
    450 	 */
    451 	_bus_dmamap_unload(t, map);
    452 }
    453 
    454 /*
    455  * Synchronize an ISA DMA map.
    456  */
    457 void
    458 _isa_bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset, bus_size_t len, int ops)
    459 {
    460 	struct atari_isa_dma_cookie *cookie = map->_dm_cookie;
    461 
    462 	/*
    463 	 * Mixing PRE and POST operations is not allowed.
    464 	 */
    465 	if ((ops & (BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE)) != 0 &&
    466 	    (ops & (BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE)) != 0)
    467 		panic("_isa_bus_dmamap_sync: mix PRE and POST");
    468 
    469 #ifdef DIAGNOSTIC
    470 	if ((ops & (BUS_DMASYNC_PREWRITE|BUS_DMASYNC_POSTREAD)) != 0) {
    471 		if (offset >= map->dm_mapsize)
    472 			panic("_isa_bus_dmamap_sync: bad offset");
    473 		if (len == 0 || (offset + len) > map->dm_mapsize)
    474 			panic("_isa_bus_dmamap_sync: bad length");
    475 	}
    476 #endif
    477 
    478 	/*
    479 	 * If we're not bouncing, just return; nothing to do.
    480 	 */
    481 	if ((cookie->id_flags & ID_IS_BOUNCING) == 0)
    482 		return;
    483 
    484 	switch (cookie->id_buftype) {
    485 	case ID_BUFTYPE_LINEAR:
    486 		/*
    487 		 * Nothing to do for pre-read.
    488 		 */
    489 
    490 		if (ops & BUS_DMASYNC_PREWRITE) {
    491 			/*
    492 			 * Copy the caller's buffer to the bounce buffer.
    493 			 */
    494 			memcpy((char *)cookie->id_bouncebuf + offset,
    495 			    (char *)cookie->id_origbuf + offset, len);
    496 		}
    497 
    498 		if (ops & BUS_DMASYNC_POSTREAD) {
    499 			/*
    500 			 * Copy the bounce buffer to the caller's buffer.
    501 			 */
    502 			memcpy((char *)cookie->id_origbuf + offset,
    503 			    (char *)cookie->id_bouncebuf + offset, len);
    504 		}
    505 
    506 		/*
    507 		 * Nothing to do for post-write.
    508 		 */
    509 		break;
    510 
    511 	case ID_BUFTYPE_MBUF:
    512 	    {
    513 		struct mbuf *m, *m0 = cookie->id_origbuf;
    514 		bus_size_t minlen, moff;
    515 
    516 		/*
    517 		 * Nothing to do for pre-read.
    518 		 */
    519 
    520 		if (ops & BUS_DMASYNC_PREWRITE) {
    521 			/*
    522 			 * Copy the caller's buffer to the bounce buffer.
    523 			 */
    524 			m_copydata(m0, offset, len,
    525 			    (char *)cookie->id_bouncebuf + offset);
    526 		}
    527 
    528 		if (ops & BUS_DMASYNC_POSTREAD) {
    529 			/*
    530 			 * Copy the bounce buffer to the caller's buffer.
    531 			 */
    532 			for (moff = offset, m = m0; m != NULL && len != 0;
    533 			     m = m->m_next) {
    534 				/* Find the beginning mbuf. */
    535 				if (moff >= m->m_len) {
    536 					moff -= m->m_len;
    537 					continue;
    538 				}
    539 
    540 				/*
    541 				 * Now at the first mbuf to sync; nail
    542 				 * each one until we have exhausted the
    543 				 * length.
    544 				 */
    545 				minlen = len < m->m_len - moff ?
    546 				    len : m->m_len - moff;
    547 
    548 				memcpy(mtod(m, char *) + moff,
    549 				    (char *)cookie->id_bouncebuf + offset,
    550 				    minlen);
    551 
    552 				moff = 0;
    553 				len -= minlen;
    554 				offset += minlen;
    555 			}
    556 		}
    557 
    558 		/*
    559 		 * Nothing to do for post-write.
    560 		 */
    561 		break;
    562 	    }
    563 
    564 	case ID_BUFTYPE_UIO:
    565 		panic("_isa_bus_dmamap_sync: ID_BUFTYPE_UIO");
    566 		break;
    567 
    568 	case ID_BUFTYPE_RAW:
    569 		panic("_isa_bus_dmamap_sync: ID_BUFTYPE_RAW");
    570 		break;
    571 
    572 	case ID_BUFTYPE_INVALID:
    573 		panic("_isa_bus_dmamap_sync: ID_BUFTYPE_INVALID");
    574 		break;
    575 
    576 	default:
    577 		printf("unknown buffer type %d\n", cookie->id_buftype);
    578 		panic("_isa_bus_dmamap_sync");
    579 	}
    580 }
    581 
    582 /*
    583  * Allocate memory safe for ISA DMA.
    584  */
    585 int
    586 _isa_bus_dmamem_alloc(bus_dma_tag_t t, bus_size_t size, bus_size_t alignment, bus_size_t boundary, bus_dma_segment_t *segs, int nsegs, int *rsegs, int flags)
    587 {
    588 	paddr_t high;
    589 
    590 	if (avail_end > ISA_DMA_BOUNCE_THRESHOLD)
    591 		high = trunc_page(ISA_DMA_BOUNCE_THRESHOLD);
    592 	else
    593 		high = trunc_page(avail_end);
    594 
    595 	return (bus_dmamem_alloc_range(t, size, alignment, boundary,
    596 	    segs, nsegs, rsegs, flags, 0, high));
    597 }
    598 
    599 /**********************************************************************
    600  * ISA DMA utility functions
    601  **********************************************************************/
    602 
    603 int
    604 _isa_dma_alloc_bouncebuf(bus_dma_tag_t t, bus_dmamap_t map, bus_size_t size, int flags)
    605 {
    606 	struct atari_isa_dma_cookie *cookie = map->_dm_cookie;
    607 	int error = 0;
    608 
    609 	cookie->id_bouncebuflen = round_page(size);
    610 	error = _isa_bus_dmamem_alloc(t, cookie->id_bouncebuflen,
    611 	    PAGE_SIZE, map->_dm_boundary, cookie->id_bouncesegs,
    612 	    map->_dm_segcnt, &cookie->id_nbouncesegs, flags);
    613 	if (error)
    614 		goto out;
    615 	error = bus_dmamem_map(t, cookie->id_bouncesegs,
    616 	    cookie->id_nbouncesegs, cookie->id_bouncebuflen,
    617 	    (void **)&cookie->id_bouncebuf, flags);
    618 
    619  out:
    620 	if (error) {
    621 		bus_dmamem_free(t, cookie->id_bouncesegs,
    622 		    cookie->id_nbouncesegs);
    623 		cookie->id_bouncebuflen = 0;
    624 		cookie->id_nbouncesegs = 0;
    625 	} else {
    626 		cookie->id_flags |= ID_HAS_BOUNCE;
    627 		STAT_INCR(isa_dma_stats_nbouncebufs);
    628 	}
    629 
    630 	return (error);
    631 }
    632 
    633 void
    634 _isa_dma_free_bouncebuf(bus_dma_tag_t t, bus_dmamap_t map)
    635 {
    636 	struct atari_isa_dma_cookie *cookie = map->_dm_cookie;
    637 
    638 	STAT_DECR(isa_dma_stats_nbouncebufs);
    639 
    640 	bus_dmamem_unmap(t, cookie->id_bouncebuf,
    641 	    cookie->id_bouncebuflen);
    642 	bus_dmamem_free(t, cookie->id_bouncesegs,
    643 	    cookie->id_nbouncesegs);
    644 	cookie->id_bouncebuflen = 0;
    645 	cookie->id_nbouncesegs = 0;
    646 	cookie->id_flags &= ~ID_HAS_BOUNCE;
    647 }
    648