xref: /netbsd-src/sys/arch/arm/arm32/bus_dma.c (revision b7b7574d3bf8eeb51a1fa3977b59142ec6434a55)
1 /*	$NetBSD: bus_dma.c,v 1.86 2014/04/10 02:44:05 matt Exp $	*/
2 
3 /*-
4  * Copyright (c) 1996, 1997, 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  *
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 #define _ARM32_BUS_DMA_PRIVATE
34 
35 #include "opt_arm_bus_space.h"
36 
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.86 2014/04/10 02:44:05 matt Exp $");
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/kernel.h>
43 #include <sys/proc.h>
44 #include <sys/buf.h>
45 #include <sys/bus.h>
46 #include <sys/cpu.h>
47 #include <sys/reboot.h>
48 #include <sys/conf.h>
49 #include <sys/file.h>
50 #include <sys/kmem.h>
51 #include <sys/mbuf.h>
52 #include <sys/vnode.h>
53 #include <sys/device.h>
54 
55 #include <uvm/uvm.h>
56 
57 #include <arm/cpufunc.h>
58 
59 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS
60 #include <dev/mm.h>
61 #endif
62 
63 #ifdef BUSDMA_COUNTERS
64 static struct evcnt bus_dma_creates =
65 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "creates");
66 static struct evcnt bus_dma_bounced_creates =
67 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "bounced creates");
68 static struct evcnt bus_dma_loads =
69 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "loads");
70 static struct evcnt bus_dma_bounced_loads =
71 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "bounced loads");
72 static struct evcnt bus_dma_coherent_loads =
73 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "coherent loads");
74 static struct evcnt bus_dma_read_bounces =
75 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "read bounces");
76 static struct evcnt bus_dma_write_bounces =
77 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "write bounces");
78 static struct evcnt bus_dma_bounced_unloads =
79 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "bounced unloads");
80 static struct evcnt bus_dma_unloads =
81 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "unloads");
82 static struct evcnt bus_dma_bounced_destroys =
83 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "bounced destroys");
84 static struct evcnt bus_dma_destroys =
85 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "destroys");
86 static struct evcnt bus_dma_sync_prereadwrite =
87 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync prereadwrite");
88 static struct evcnt bus_dma_sync_preread_begin =
89 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync preread begin");
90 static struct evcnt bus_dma_sync_preread =
91 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync preread");
92 static struct evcnt bus_dma_sync_preread_tail =
93 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync preread tail");
94 static struct evcnt bus_dma_sync_prewrite =
95 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync prewrite");
96 static struct evcnt bus_dma_sync_postread =
97 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync postread");
98 static struct evcnt bus_dma_sync_postreadwrite =
99 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync postreadwrite");
100 static struct evcnt bus_dma_sync_postwrite =
101 	EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "busdma", "sync postwrite");
102 
103 EVCNT_ATTACH_STATIC(bus_dma_creates);
104 EVCNT_ATTACH_STATIC(bus_dma_bounced_creates);
105 EVCNT_ATTACH_STATIC(bus_dma_loads);
106 EVCNT_ATTACH_STATIC(bus_dma_bounced_loads);
107 EVCNT_ATTACH_STATIC(bus_dma_coherent_loads);
108 EVCNT_ATTACH_STATIC(bus_dma_read_bounces);
109 EVCNT_ATTACH_STATIC(bus_dma_write_bounces);
110 EVCNT_ATTACH_STATIC(bus_dma_unloads);
111 EVCNT_ATTACH_STATIC(bus_dma_bounced_unloads);
112 EVCNT_ATTACH_STATIC(bus_dma_destroys);
113 EVCNT_ATTACH_STATIC(bus_dma_bounced_destroys);
114 EVCNT_ATTACH_STATIC(bus_dma_sync_prereadwrite);
115 EVCNT_ATTACH_STATIC(bus_dma_sync_preread_begin);
116 EVCNT_ATTACH_STATIC(bus_dma_sync_preread);
117 EVCNT_ATTACH_STATIC(bus_dma_sync_preread_tail);
118 EVCNT_ATTACH_STATIC(bus_dma_sync_prewrite);
119 EVCNT_ATTACH_STATIC(bus_dma_sync_postread);
120 EVCNT_ATTACH_STATIC(bus_dma_sync_postreadwrite);
121 EVCNT_ATTACH_STATIC(bus_dma_sync_postwrite);
122 
123 #define	STAT_INCR(x)	(bus_dma_ ## x.ev_count++)
124 #else
125 #define	STAT_INCR(x)	/*(bus_dma_ ## x.ev_count++)*/
126 #endif
127 
128 int	_bus_dmamap_load_buffer(bus_dma_tag_t, bus_dmamap_t, void *,
129 	    bus_size_t, struct vmspace *, int);
130 static struct arm32_dma_range *
131 	_bus_dma_paddr_inrange(struct arm32_dma_range *, int, paddr_t);
132 
133 /*
134  * Check to see if the specified page is in an allowed DMA range.
135  */
136 inline struct arm32_dma_range *
137 _bus_dma_paddr_inrange(struct arm32_dma_range *ranges, int nranges,
138     bus_addr_t curaddr)
139 {
140 	struct arm32_dma_range *dr;
141 	int i;
142 
143 	for (i = 0, dr = ranges; i < nranges; i++, dr++) {
144 		if (curaddr >= dr->dr_sysbase &&
145 		    curaddr < (dr->dr_sysbase + dr->dr_len))
146 			return (dr);
147 	}
148 
149 	return (NULL);
150 }
151 
152 /*
153  * Check to see if the specified busaddr is in an allowed DMA range.
154  */
155 static inline paddr_t
156 _bus_dma_busaddr_to_paddr(bus_dma_tag_t t, bus_addr_t curaddr)
157 {
158 	struct arm32_dma_range *dr;
159 	u_int i;
160 
161 	if (t->_nranges == 0)
162 		return curaddr;
163 
164 	for (i = 0, dr = t->_ranges; i < t->_nranges; i++, dr++) {
165 		if (dr->dr_busbase <= curaddr
166 		    && curaddr < dr->dr_busbase + dr->dr_len)
167 			return curaddr - dr->dr_busbase + dr->dr_sysbase;
168 	}
169 	panic("%s: curaddr %#lx not in range", __func__, curaddr);
170 }
171 
172 /*
173  * Common function to load the specified physical address into the
174  * DMA map, coalescing segments and boundary checking as necessary.
175  */
176 static int
177 _bus_dmamap_load_paddr(bus_dma_tag_t t, bus_dmamap_t map,
178     bus_addr_t paddr, bus_size_t size, bool coherent)
179 {
180 	bus_dma_segment_t * const segs = map->dm_segs;
181 	int nseg = map->dm_nsegs;
182 	bus_addr_t lastaddr;
183 	bus_addr_t bmask = ~(map->_dm_boundary - 1);
184 	bus_addr_t curaddr;
185 	bus_size_t sgsize;
186 	uint32_t _ds_flags = coherent ? _BUS_DMAMAP_COHERENT : 0;
187 
188 	if (nseg > 0)
189 		lastaddr = segs[nseg-1].ds_addr + segs[nseg-1].ds_len;
190 	else
191 		lastaddr = 0xdead;
192 
193  again:
194 	sgsize = size;
195 
196 	/* Make sure we're in an allowed DMA range. */
197 	if (t->_ranges != NULL) {
198 		/* XXX cache last result? */
199 		const struct arm32_dma_range * const dr =
200 		    _bus_dma_paddr_inrange(t->_ranges, t->_nranges, paddr);
201 		if (dr == NULL)
202 			return (EINVAL);
203 
204 		/*
205 		 * If this region is coherent, mark the segment as coherent.
206 		 */
207 		_ds_flags |= dr->dr_flags & _BUS_DMAMAP_COHERENT;
208 
209 		/*
210 		 * In a valid DMA range.  Translate the physical
211 		 * memory address to an address in the DMA window.
212 		 */
213 		curaddr = (paddr - dr->dr_sysbase) + dr->dr_busbase;
214 #if 0
215 		printf("%p: %#lx: range %#lx/%#lx/%#lx/%#x: %#x <-- %#lx\n",
216 		    t, paddr, dr->dr_sysbase, dr->dr_busbase,
217 		    dr->dr_len, dr->dr_flags, _ds_flags, curaddr);
218 #endif
219 	} else
220 		curaddr = paddr;
221 
222 	/*
223 	 * Make sure we don't cross any boundaries.
224 	 */
225 	if (map->_dm_boundary > 0) {
226 		bus_addr_t baddr;	/* next boundary address */
227 
228 		baddr = (curaddr + map->_dm_boundary) & bmask;
229 		if (sgsize > (baddr - curaddr))
230 			sgsize = (baddr - curaddr);
231 	}
232 
233 	/*
234 	 * Insert chunk into a segment, coalescing with the
235 	 * previous segment if possible.
236 	 */
237 	if (nseg > 0 && curaddr == lastaddr &&
238 	    segs[nseg-1].ds_len + sgsize <= map->dm_maxsegsz &&
239 	    ((segs[nseg-1]._ds_flags ^ _ds_flags) & _BUS_DMAMAP_COHERENT) == 0 &&
240 	    (map->_dm_boundary == 0 ||
241 	     (segs[nseg-1].ds_addr & bmask) == (curaddr & bmask))) {
242 	     	/* coalesce */
243 		segs[nseg-1].ds_len += sgsize;
244 	} else if (nseg >= map->_dm_segcnt) {
245 		return (EFBIG);
246 	} else {
247 		/* new segment */
248 		segs[nseg].ds_addr = curaddr;
249 		segs[nseg].ds_len = sgsize;
250 		segs[nseg]._ds_flags = _ds_flags;
251 		nseg++;
252 	}
253 
254 	lastaddr = curaddr + sgsize;
255 
256 	paddr += sgsize;
257 	size -= sgsize;
258 	if (size > 0)
259 		goto again;
260 
261 	map->_dm_flags &= (_ds_flags & _BUS_DMAMAP_COHERENT);
262 	map->dm_nsegs = nseg;
263 	return (0);
264 }
265 
266 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
267 static int _bus_dma_alloc_bouncebuf(bus_dma_tag_t t, bus_dmamap_t map,
268 	    bus_size_t size, int flags);
269 static void _bus_dma_free_bouncebuf(bus_dma_tag_t t, bus_dmamap_t map);
270 static int _bus_dma_uiomove(void *buf, struct uio *uio, size_t n,
271 	    int direction);
272 
273 static int
274 _bus_dma_load_bouncebuf(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
275 	size_t buflen, int buftype, int flags)
276 {
277 	struct arm32_bus_dma_cookie * const cookie = map->_dm_cookie;
278 	struct vmspace * const vm = vmspace_kernel();
279 	int error;
280 
281 	KASSERT(cookie != NULL);
282 	KASSERT(cookie->id_flags & _BUS_DMA_MIGHT_NEED_BOUNCE);
283 
284 	/*
285 	 * Allocate bounce pages, if necessary.
286 	 */
287 	if ((cookie->id_flags & _BUS_DMA_HAS_BOUNCE) == 0) {
288 		error = _bus_dma_alloc_bouncebuf(t, map, buflen, flags);
289 		if (error)
290 			return (error);
291 	}
292 
293 	/*
294 	 * Cache a pointer to the caller's buffer and load the DMA map
295 	 * with the bounce buffer.
296 	 */
297 	cookie->id_origbuf = buf;
298 	cookie->id_origbuflen = buflen;
299 	error = _bus_dmamap_load_buffer(t, map, cookie->id_bouncebuf,
300 	    buflen, vm, flags);
301 	if (error)
302 		return (error);
303 
304 	STAT_INCR(bounced_loads);
305 	map->dm_mapsize = buflen;
306 	map->_dm_vmspace = vm;
307 	map->_dm_buftype = buftype;
308 
309 	/* ...so _bus_dmamap_sync() knows we're bouncing */
310 	map->_dm_flags |= _BUS_DMAMAP_IS_BOUNCING;
311 	cookie->id_flags |= _BUS_DMA_IS_BOUNCING;
312 	return 0;
313 }
314 #endif /* _ARM32_NEED_BUS_DMA_BOUNCE */
315 
316 /*
317  * Common function for DMA map creation.  May be called by bus-specific
318  * DMA map creation functions.
319  */
320 int
321 _bus_dmamap_create(bus_dma_tag_t t, bus_size_t size, int nsegments,
322     bus_size_t maxsegsz, bus_size_t boundary, int flags, bus_dmamap_t *dmamp)
323 {
324 	struct arm32_bus_dmamap *map;
325 	void *mapstore;
326 
327 #ifdef DEBUG_DMA
328 	printf("dmamap_create: t=%p size=%lx nseg=%x msegsz=%lx boundary=%lx flags=%x\n",
329 	    t, size, nsegments, maxsegsz, boundary, flags);
330 #endif	/* DEBUG_DMA */
331 
332 	/*
333 	 * Allocate and initialize the DMA map.  The end of the map
334 	 * is a variable-sized array of segments, so we allocate enough
335 	 * room for them in one shot.
336 	 *
337 	 * Note we don't preserve the WAITOK or NOWAIT flags.  Preservation
338 	 * of ALLOCNOW notifies others that we've reserved these resources,
339 	 * and they are not to be freed.
340 	 *
341 	 * The bus_dmamap_t includes one bus_dma_segment_t, hence
342 	 * the (nsegments - 1).
343 	 */
344 	const size_t mapsize = sizeof(struct arm32_bus_dmamap) +
345 	    (sizeof(bus_dma_segment_t) * (nsegments - 1));
346 	const int zallocflags = (flags & BUS_DMA_NOWAIT) ? KM_NOSLEEP : KM_SLEEP;
347 	if ((mapstore = kmem_intr_zalloc(mapsize, zallocflags)) == NULL)
348 		return (ENOMEM);
349 
350 	map = (struct arm32_bus_dmamap *)mapstore;
351 	map->_dm_size = size;
352 	map->_dm_segcnt = nsegments;
353 	map->_dm_maxmaxsegsz = maxsegsz;
354 	map->_dm_boundary = boundary;
355 	map->_dm_flags = flags & ~(BUS_DMA_WAITOK|BUS_DMA_NOWAIT);
356 	map->_dm_origbuf = NULL;
357 	map->_dm_buftype = _BUS_DMA_BUFTYPE_INVALID;
358 	map->_dm_vmspace = vmspace_kernel();
359 	map->_dm_cookie = NULL;
360 	map->dm_maxsegsz = maxsegsz;
361 	map->dm_mapsize = 0;		/* no valid mappings */
362 	map->dm_nsegs = 0;
363 
364 	*dmamp = map;
365 
366 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
367 	struct arm32_bus_dma_cookie *cookie;
368 	int cookieflags;
369 	void *cookiestore;
370 	int error;
371 
372 	cookieflags = 0;
373 
374 	if (t->_may_bounce != NULL) {
375 		error = (*t->_may_bounce)(t, map, flags, &cookieflags);
376 		if (error != 0)
377 			goto out;
378 	}
379 
380 	if (t->_ranges != NULL)
381 		cookieflags |= _BUS_DMA_MIGHT_NEED_BOUNCE;
382 
383 	if ((cookieflags & _BUS_DMA_MIGHT_NEED_BOUNCE) == 0) {
384 		STAT_INCR(creates);
385 		return 0;
386 	}
387 
388 	const size_t cookiesize = sizeof(struct arm32_bus_dma_cookie) +
389 	    (sizeof(bus_dma_segment_t) * map->_dm_segcnt);
390 
391 	/*
392 	 * Allocate our cookie.
393 	 */
394 	if ((cookiestore = kmem_intr_zalloc(cookiesize, zallocflags)) == NULL) {
395 		error = ENOMEM;
396 		goto out;
397 	}
398 	cookie = (struct arm32_bus_dma_cookie *)cookiestore;
399 	cookie->id_flags = cookieflags;
400 	map->_dm_cookie = cookie;
401 	STAT_INCR(bounced_creates);
402 
403 	error = _bus_dma_alloc_bouncebuf(t, map, size, flags);
404  out:
405 	if (error)
406 		_bus_dmamap_destroy(t, map);
407 #else
408 	STAT_INCR(creates);
409 #endif /* _ARM32_NEED_BUS_DMA_BOUNCE */
410 
411 #ifdef DEBUG_DMA
412 	printf("dmamap_create:map=%p\n", map);
413 #endif	/* DEBUG_DMA */
414 	return (0);
415 }
416 
417 /*
418  * Common function for DMA map destruction.  May be called by bus-specific
419  * DMA map destruction functions.
420  */
421 void
422 _bus_dmamap_destroy(bus_dma_tag_t t, bus_dmamap_t map)
423 {
424 
425 #ifdef DEBUG_DMA
426 	printf("dmamap_destroy: t=%p map=%p\n", t, map);
427 #endif	/* DEBUG_DMA */
428 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
429 	struct arm32_bus_dma_cookie *cookie = map->_dm_cookie;
430 
431 	/*
432 	 * Free any bounce pages this map might hold.
433 	 */
434 	if (cookie != NULL) {
435 		const size_t cookiesize = sizeof(struct arm32_bus_dma_cookie) +
436 		    (sizeof(bus_dma_segment_t) * map->_dm_segcnt);
437 
438 		if (cookie->id_flags & _BUS_DMA_IS_BOUNCING)
439 			STAT_INCR(bounced_unloads);
440 		map->dm_nsegs = 0;
441 		if (cookie->id_flags & _BUS_DMA_HAS_BOUNCE)
442 			_bus_dma_free_bouncebuf(t, map);
443 		STAT_INCR(bounced_destroys);
444 		kmem_intr_free(cookie, cookiesize);
445 	} else
446 #endif
447 	STAT_INCR(destroys);
448 
449 	if (map->dm_nsegs > 0)
450 		STAT_INCR(unloads);
451 
452 	const size_t mapsize = sizeof(struct arm32_bus_dmamap) +
453 	    (sizeof(bus_dma_segment_t) * (map->_dm_segcnt - 1));
454 	kmem_intr_free(map, mapsize);
455 }
456 
457 /*
458  * Common function for loading a DMA map with a linear buffer.  May
459  * be called by bus-specific DMA map load functions.
460  */
461 int
462 _bus_dmamap_load(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
463     bus_size_t buflen, struct proc *p, int flags)
464 {
465 	struct vmspace *vm;
466 	int error;
467 
468 #ifdef DEBUG_DMA
469 	printf("dmamap_load: t=%p map=%p buf=%p len=%lx p=%p f=%d\n",
470 	    t, map, buf, buflen, p, flags);
471 #endif	/* DEBUG_DMA */
472 
473 	if (map->dm_nsegs > 0) {
474 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
475 		struct arm32_bus_dma_cookie *cookie = map->_dm_cookie;
476 		if (cookie != NULL) {
477 			if (cookie->id_flags & _BUS_DMA_IS_BOUNCING) {
478 				STAT_INCR(bounced_unloads);
479 				cookie->id_flags &= ~_BUS_DMA_IS_BOUNCING;
480 				map->_dm_flags &= ~_BUS_DMAMAP_IS_BOUNCING;
481 			}
482 		} else
483 #endif
484 		STAT_INCR(unloads);
485 	}
486 
487 	/*
488 	 * Make sure that on error condition we return "no valid mappings".
489 	 */
490 	map->dm_mapsize = 0;
491 	map->dm_nsegs = 0;
492 	map->_dm_buftype = _BUS_DMA_BUFTYPE_INVALID;
493 	KASSERTMSG(map->dm_maxsegsz <= map->_dm_maxmaxsegsz,
494 	    "dm_maxsegsz %lu _dm_maxmaxsegsz %lu",
495 	    map->dm_maxsegsz, map->_dm_maxmaxsegsz);
496 
497 	if (buflen > map->_dm_size)
498 		return (EINVAL);
499 
500 	if (p != NULL) {
501 		vm = p->p_vmspace;
502 	} else {
503 		vm = vmspace_kernel();
504 	}
505 
506 	/* _bus_dmamap_load_buffer() clears this if we're not... */
507 	map->_dm_flags |= _BUS_DMAMAP_COHERENT;
508 
509 	error = _bus_dmamap_load_buffer(t, map, buf, buflen, vm, flags);
510 	if (error == 0) {
511 		map->dm_mapsize = buflen;
512 		map->_dm_vmspace = vm;
513 		map->_dm_origbuf = buf;
514 		map->_dm_buftype = _BUS_DMA_BUFTYPE_LINEAR;
515 		if (map->_dm_flags & _BUS_DMAMAP_COHERENT) {
516 			STAT_INCR(coherent_loads);
517 		} else {
518 			STAT_INCR(loads);
519 		}
520 		return 0;
521 	}
522 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
523 	struct arm32_bus_dma_cookie * const cookie = map->_dm_cookie;
524 	if (cookie != NULL && (cookie->id_flags & _BUS_DMA_MIGHT_NEED_BOUNCE)) {
525 		error = _bus_dma_load_bouncebuf(t, map, buf, buflen,
526 		    _BUS_DMA_BUFTYPE_LINEAR, flags);
527 	}
528 #endif
529 	return (error);
530 }
531 
532 /*
533  * Like _bus_dmamap_load(), but for mbufs.
534  */
535 int
536 _bus_dmamap_load_mbuf(bus_dma_tag_t t, bus_dmamap_t map, struct mbuf *m0,
537     int flags)
538 {
539 	int error;
540 	struct mbuf *m;
541 
542 #ifdef DEBUG_DMA
543 	printf("dmamap_load_mbuf: t=%p map=%p m0=%p f=%d\n",
544 	    t, map, m0, flags);
545 #endif	/* DEBUG_DMA */
546 
547 	if (map->dm_nsegs > 0) {
548 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
549 		struct arm32_bus_dma_cookie *cookie = map->_dm_cookie;
550 		if (cookie != NULL) {
551 			if (cookie->id_flags & _BUS_DMA_IS_BOUNCING) {
552 				STAT_INCR(bounced_unloads);
553 				cookie->id_flags &= ~_BUS_DMA_IS_BOUNCING;
554 				map->_dm_flags &= ~_BUS_DMAMAP_IS_BOUNCING;
555 			}
556 		} else
557 #endif
558 		STAT_INCR(unloads);
559 	}
560 
561 	/*
562 	 * Make sure that on error condition we return "no valid mappings."
563 	 */
564 	map->dm_mapsize = 0;
565 	map->dm_nsegs = 0;
566 	map->_dm_buftype = _BUS_DMA_BUFTYPE_INVALID;
567 	KASSERTMSG(map->dm_maxsegsz <= map->_dm_maxmaxsegsz,
568 	    "dm_maxsegsz %lu _dm_maxmaxsegsz %lu",
569 	    map->dm_maxsegsz, map->_dm_maxmaxsegsz);
570 
571 	KASSERT(m0->m_flags & M_PKTHDR);
572 
573 	if (m0->m_pkthdr.len > map->_dm_size)
574 		return (EINVAL);
575 
576 	/* _bus_dmamap_load_paddr() clears this if we're not... */
577 	map->_dm_flags |= _BUS_DMAMAP_COHERENT;
578 
579 	error = 0;
580 	for (m = m0; m != NULL && error == 0; m = m->m_next) {
581 		int offset;
582 		int remainbytes;
583 		const struct vm_page * const *pgs;
584 		paddr_t paddr;
585 		int size;
586 
587 		if (m->m_len == 0)
588 			continue;
589 		/*
590 		 * Don't allow reads in read-only mbufs.
591 		 */
592 		if (M_ROMAP(m) && (flags & BUS_DMA_READ)) {
593 			error = EFAULT;
594 			break;
595 		}
596 		switch (m->m_flags & (M_EXT|M_CLUSTER|M_EXT_PAGES)) {
597 		case M_EXT|M_CLUSTER:
598 			/* XXX KDASSERT */
599 			KASSERT(m->m_ext.ext_paddr != M_PADDR_INVALID);
600 			paddr = m->m_ext.ext_paddr +
601 			    (m->m_data - m->m_ext.ext_buf);
602 			size = m->m_len;
603 			error = _bus_dmamap_load_paddr(t, map, paddr, size,
604 			    false);
605 			break;
606 
607 		case M_EXT|M_EXT_PAGES:
608 			KASSERT(m->m_ext.ext_buf <= m->m_data);
609 			KASSERT(m->m_data <=
610 			    m->m_ext.ext_buf + m->m_ext.ext_size);
611 
612 			offset = (vaddr_t)m->m_data -
613 			    trunc_page((vaddr_t)m->m_ext.ext_buf);
614 			remainbytes = m->m_len;
615 
616 			/* skip uninteresting pages */
617 			pgs = (const struct vm_page * const *)
618 			    m->m_ext.ext_pgs + (offset >> PAGE_SHIFT);
619 
620 			offset &= PAGE_MASK;	/* offset in the first page */
621 
622 			/* load each page */
623 			while (remainbytes > 0) {
624 				const struct vm_page *pg;
625 
626 				size = MIN(remainbytes, PAGE_SIZE - offset);
627 
628 				pg = *pgs++;
629 				KASSERT(pg);
630 				paddr = VM_PAGE_TO_PHYS(pg) + offset;
631 
632 				error = _bus_dmamap_load_paddr(t, map,
633 				    paddr, size, false);
634 				if (error)
635 					break;
636 				offset = 0;
637 				remainbytes -= size;
638 			}
639 			break;
640 
641 		case 0:
642 			paddr = m->m_paddr + M_BUFOFFSET(m) +
643 			    (m->m_data - M_BUFADDR(m));
644 			size = m->m_len;
645 			error = _bus_dmamap_load_paddr(t, map, paddr, size,
646 			    false);
647 			break;
648 
649 		default:
650 			error = _bus_dmamap_load_buffer(t, map, m->m_data,
651 			    m->m_len, vmspace_kernel(), flags);
652 		}
653 	}
654 	if (error == 0) {
655 		map->dm_mapsize = m0->m_pkthdr.len;
656 		map->_dm_origbuf = m0;
657 		map->_dm_buftype = _BUS_DMA_BUFTYPE_MBUF;
658 		map->_dm_vmspace = vmspace_kernel();	/* always kernel */
659 		if (map->_dm_flags & _BUS_DMAMAP_COHERENT) {
660 			STAT_INCR(coherent_loads);
661 		} else {
662 			STAT_INCR(loads);
663 		}
664 		return 0;
665 	}
666 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
667 	struct arm32_bus_dma_cookie * const cookie = map->_dm_cookie;
668 	if (cookie != NULL && (cookie->id_flags & _BUS_DMA_MIGHT_NEED_BOUNCE)) {
669 		error = _bus_dma_load_bouncebuf(t, map, m0, m0->m_pkthdr.len,
670 		    _BUS_DMA_BUFTYPE_MBUF, flags);
671 	}
672 #endif
673 	return (error);
674 }
675 
676 /*
677  * Like _bus_dmamap_load(), but for uios.
678  */
679 int
680 _bus_dmamap_load_uio(bus_dma_tag_t t, bus_dmamap_t map, struct uio *uio,
681     int flags)
682 {
683 	int i, error;
684 	bus_size_t minlen, resid;
685 	struct iovec *iov;
686 	void *addr;
687 
688 	/*
689 	 * Make sure that on error condition we return "no valid mappings."
690 	 */
691 	map->dm_mapsize = 0;
692 	map->dm_nsegs = 0;
693 	KASSERTMSG(map->dm_maxsegsz <= map->_dm_maxmaxsegsz,
694 	    "dm_maxsegsz %lu _dm_maxmaxsegsz %lu",
695 	    map->dm_maxsegsz, map->_dm_maxmaxsegsz);
696 
697 	resid = uio->uio_resid;
698 	iov = uio->uio_iov;
699 
700 	/* _bus_dmamap_load_buffer() clears this if we're not... */
701 	map->_dm_flags |= _BUS_DMAMAP_COHERENT;
702 
703 	error = 0;
704 	for (i = 0; i < uio->uio_iovcnt && resid != 0 && error == 0; i++) {
705 		/*
706 		 * Now at the first iovec to load.  Load each iovec
707 		 * until we have exhausted the residual count.
708 		 */
709 		minlen = resid < iov[i].iov_len ? resid : iov[i].iov_len;
710 		addr = (void *)iov[i].iov_base;
711 
712 		error = _bus_dmamap_load_buffer(t, map, addr, minlen,
713 		    uio->uio_vmspace, flags);
714 
715 		resid -= minlen;
716 	}
717 	if (error == 0) {
718 		map->dm_mapsize = uio->uio_resid;
719 		map->_dm_origbuf = uio;
720 		map->_dm_buftype = _BUS_DMA_BUFTYPE_UIO;
721 		map->_dm_vmspace = uio->uio_vmspace;
722 		if (map->_dm_flags & _BUS_DMAMAP_COHERENT) {
723 			STAT_INCR(coherent_loads);
724 		} else {
725 			STAT_INCR(loads);
726 		}
727 	}
728 	return (error);
729 }
730 
731 /*
732  * Like _bus_dmamap_load(), but for raw memory allocated with
733  * bus_dmamem_alloc().
734  */
735 int
736 _bus_dmamap_load_raw(bus_dma_tag_t t, bus_dmamap_t map,
737     bus_dma_segment_t *segs, int nsegs, bus_size_t size, int flags)
738 {
739 
740 	panic("_bus_dmamap_load_raw: not implemented");
741 }
742 
743 /*
744  * Common function for unloading a DMA map.  May be called by
745  * bus-specific DMA map unload functions.
746  */
747 void
748 _bus_dmamap_unload(bus_dma_tag_t t, bus_dmamap_t map)
749 {
750 
751 #ifdef DEBUG_DMA
752 	printf("dmamap_unload: t=%p map=%p\n", t, map);
753 #endif	/* DEBUG_DMA */
754 
755 	/*
756 	 * No resources to free; just mark the mappings as
757 	 * invalid.
758 	 */
759 	map->dm_mapsize = 0;
760 	map->dm_nsegs = 0;
761 	map->_dm_origbuf = NULL;
762 	map->_dm_buftype = _BUS_DMA_BUFTYPE_INVALID;
763 	map->_dm_vmspace = NULL;
764 }
765 
766 static void
767 _bus_dmamap_sync_segment(vaddr_t va, paddr_t pa, vsize_t len, int ops, bool readonly_p)
768 {
769 	KASSERTMSG((va & PAGE_MASK) == (pa & PAGE_MASK),
770 	    "va %#lx pa %#lx", va, pa);
771 #if 0
772 	printf("sync_segment: va=%#lx pa=%#lx len=%#lx ops=%#x ro=%d\n",
773 	    va, pa, len, ops, readonly_p);
774 #endif
775 
776 	switch (ops) {
777 	case BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE:
778 		if (!readonly_p) {
779 			STAT_INCR(sync_prereadwrite);
780 			cpu_dcache_wbinv_range(va, len);
781 			cpu_sdcache_wbinv_range(va, pa, len);
782 			break;
783 		}
784 		/* FALLTHROUGH */
785 
786 	case BUS_DMASYNC_PREREAD: {
787 		const size_t line_size = arm_dcache_align;
788 		const size_t line_mask = arm_dcache_align_mask;
789 		vsize_t misalignment = va & line_mask;
790 		if (misalignment) {
791 			va -= misalignment;
792 			pa -= misalignment;
793 			len += misalignment;
794 			STAT_INCR(sync_preread_begin);
795 			cpu_dcache_wbinv_range(va, line_size);
796 			cpu_sdcache_wbinv_range(va, pa, line_size);
797 			if (len <= line_size)
798 				break;
799 			va += line_size;
800 			pa += line_size;
801 			len -= line_size;
802 		}
803 		misalignment = len & line_mask;
804 		len -= misalignment;
805 		if (len > 0) {
806 			STAT_INCR(sync_preread);
807 			cpu_dcache_inv_range(va, len);
808 			cpu_sdcache_inv_range(va, pa, len);
809 		}
810 		if (misalignment) {
811 			va += len;
812 			pa += len;
813 			STAT_INCR(sync_preread_tail);
814 			cpu_dcache_wbinv_range(va, line_size);
815 			cpu_sdcache_wbinv_range(va, pa, line_size);
816 		}
817 		break;
818 	}
819 
820 	case BUS_DMASYNC_PREWRITE:
821 		STAT_INCR(sync_prewrite);
822 		cpu_dcache_wb_range(va, len);
823 		cpu_sdcache_wb_range(va, pa, len);
824 		break;
825 
826 #ifdef CPU_CORTEX
827 	/*
828 	 * Cortex CPUs can do speculative loads so we need to clean the cache
829 	 * after a DMA read to deal with any speculatively loaded cache lines.
830 	 * Since these can't be dirty, we can just invalidate them and don't
831 	 * have to worry about having to write back their contents.
832 	 */
833 	case BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE:
834 		STAT_INCR(sync_postreadwrite);
835 		cpu_dcache_inv_range(va, len);
836 		cpu_sdcache_inv_range(va, pa, len);
837 		break;
838 	case BUS_DMASYNC_POSTREAD:
839 		STAT_INCR(sync_postread);
840 		cpu_dcache_inv_range(va, len);
841 		cpu_sdcache_inv_range(va, pa, len);
842 		break;
843 #endif
844 	}
845 }
846 
847 static inline void
848 _bus_dmamap_sync_linear(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
849     bus_size_t len, int ops)
850 {
851 	bus_dma_segment_t *ds = map->dm_segs;
852 	vaddr_t va = (vaddr_t) map->_dm_origbuf;
853 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
854 	if (map->_dm_flags & _BUS_DMAMAP_IS_BOUNCING) {
855 		struct arm32_bus_dma_cookie * const cookie = map->_dm_cookie;
856 		va = (vaddr_t) cookie->id_bouncebuf;
857 	}
858 #endif
859 
860 	while (len > 0) {
861 		while (offset >= ds->ds_len) {
862 			offset -= ds->ds_len;
863 			va += ds->ds_len;
864 			ds++;
865 		}
866 
867 		paddr_t pa = _bus_dma_busaddr_to_paddr(t, ds->ds_addr + offset);
868 		size_t seglen = min(len, ds->ds_len - offset);
869 
870 		if ((ds->_ds_flags & _BUS_DMAMAP_COHERENT) == 0)
871 			_bus_dmamap_sync_segment(va + offset, pa, seglen, ops,
872 			    false);
873 
874 		offset += seglen;
875 		len -= seglen;
876 	}
877 }
878 
879 static inline void
880 _bus_dmamap_sync_mbuf(bus_dma_tag_t t, bus_dmamap_t map, bus_size_t offset,
881     bus_size_t len, int ops)
882 {
883 	bus_dma_segment_t *ds = map->dm_segs;
884 	struct mbuf *m = map->_dm_origbuf;
885 	bus_size_t voff = offset;
886 	bus_size_t ds_off = offset;
887 
888 	while (len > 0) {
889 		/* Find the current dma segment */
890 		while (ds_off >= ds->ds_len) {
891 			ds_off -= ds->ds_len;
892 			ds++;
893 		}
894 		/* Find the current mbuf. */
895 		while (voff >= m->m_len) {
896 			voff -= m->m_len;
897 			m = m->m_next;
898 		}
899 
900 		/*
901 		 * Now at the first mbuf to sync; nail each one until
902 		 * we have exhausted the length.
903 		 */
904 		vsize_t seglen = min(len, min(m->m_len - voff, ds->ds_len - ds_off));
905 		vaddr_t va = mtod(m, vaddr_t) + voff;
906 		paddr_t pa = _bus_dma_busaddr_to_paddr(t, ds->ds_addr + ds_off);
907 
908 		/*
909 		 * We can save a lot of work here if we know the mapping
910 		 * is read-only at the MMU:
911 		 *
912 		 * If a mapping is read-only, no dirty cache blocks will
913 		 * exist for it.  If a writable mapping was made read-only,
914 		 * we know any dirty cache lines for the range will have
915 		 * been cleaned for us already.  Therefore, if the upper
916 		 * layer can tell us we have a read-only mapping, we can
917 		 * skip all cache cleaning.
918 		 *
919 		 * NOTE: This only works if we know the pmap cleans pages
920 		 * before making a read-write -> read-only transition.  If
921 		 * this ever becomes non-true (e.g. Physically Indexed
922 		 * cache), this will have to be revisited.
923 		 */
924 
925 		if ((ds->_ds_flags & _BUS_DMAMAP_COHERENT) == 0)
926 			_bus_dmamap_sync_segment(va, pa, seglen, ops,
927 			    M_ROMAP(m));
928 		voff += seglen;
929 		ds_off += seglen;
930 		len -= seglen;
931 	}
932 }
933 
934 static inline void
935 _bus_dmamap_sync_uio(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
936     bus_size_t len, int ops)
937 {
938 	bus_dma_segment_t *ds = map->dm_segs;
939 	struct uio *uio = map->_dm_origbuf;
940 	struct iovec *iov = uio->uio_iov;
941 	bus_size_t voff = offset;
942 	bus_size_t ds_off = offset;
943 
944 	while (len > 0) {
945 		/* Find the current dma segment */
946 		while (ds_off >= ds->ds_len) {
947 			ds_off -= ds->ds_len;
948 			ds++;
949 		}
950 
951 		/* Find the current iovec. */
952 		while (voff >= iov->iov_len) {
953 			voff -= iov->iov_len;
954 			iov++;
955 		}
956 
957 		/*
958 		 * Now at the first iovec to sync; nail each one until
959 		 * we have exhausted the length.
960 		 */
961 		vsize_t seglen = min(len, min(iov->iov_len - voff, ds->ds_len - ds_off));
962 		vaddr_t va = (vaddr_t) iov->iov_base + voff;
963 		paddr_t pa = _bus_dma_busaddr_to_paddr(t, ds->ds_addr + ds_off);
964 
965 		if ((ds->_ds_flags & _BUS_DMAMAP_COHERENT) == 0)
966 			_bus_dmamap_sync_segment(va, pa, seglen, ops, false);
967 
968 		voff += seglen;
969 		ds_off += seglen;
970 		len -= seglen;
971 	}
972 }
973 
974 /*
975  * Common function for DMA map synchronization.  May be called
976  * by bus-specific DMA map synchronization functions.
977  *
978  * This version works for the Virtually Indexed Virtually Tagged
979  * cache found on 32-bit ARM processors.
980  *
981  * XXX Should have separate versions for write-through vs.
982  * XXX write-back caches.  We currently assume write-back
983  * XXX here, which is not as efficient as it could be for
984  * XXX the write-through case.
985  */
986 void
987 _bus_dmamap_sync(bus_dma_tag_t t, bus_dmamap_t map, bus_addr_t offset,
988     bus_size_t len, int ops)
989 {
990 #ifdef DEBUG_DMA
991 	printf("dmamap_sync: t=%p map=%p offset=%lx len=%lx ops=%x\n",
992 	    t, map, offset, len, ops);
993 #endif	/* DEBUG_DMA */
994 
995 	/*
996 	 * Mixing of PRE and POST operations is not allowed.
997 	 */
998 	if ((ops & (BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE)) != 0 &&
999 	    (ops & (BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE)) != 0)
1000 		panic("_bus_dmamap_sync: mix PRE and POST");
1001 
1002 	KASSERTMSG(offset < map->dm_mapsize,
1003 	    "offset %lu mapsize %lu",
1004 	    offset, map->dm_mapsize);
1005 	KASSERTMSG(len > 0 && offset + len <= map->dm_mapsize,
1006 	    "len %lu offset %lu mapsize %lu",
1007 	    len, offset, map->dm_mapsize);
1008 
1009 	/*
1010 	 * For a virtually-indexed write-back cache, we need
1011 	 * to do the following things:
1012 	 *
1013 	 *	PREREAD -- Invalidate the D-cache.  We do this
1014 	 *	here in case a write-back is required by the back-end.
1015 	 *
1016 	 *	PREWRITE -- Write-back the D-cache.  Note that if
1017 	 *	we are doing a PREREAD|PREWRITE, we can collapse
1018 	 *	the whole thing into a single Wb-Inv.
1019 	 *
1020 	 *	POSTREAD -- Re-invalidate the D-cache in case speculative
1021 	 *	memory accesses caused cachelines to become valid with now
1022 	 *	invalid data.
1023 	 *
1024 	 *	POSTWRITE -- Nothing.
1025 	 */
1026 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1027 	const bool bouncing = (map->_dm_flags & _BUS_DMAMAP_IS_BOUNCING);
1028 #else
1029 	const bool bouncing = false;
1030 #endif
1031 
1032 	const int pre_ops = ops & (BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);
1033 #ifdef CPU_CORTEX
1034 	const int post_ops = ops & (BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
1035 #else
1036 	const int post_ops = 0;
1037 #endif
1038 	if (!bouncing && pre_ops == 0 && post_ops == BUS_DMASYNC_POSTWRITE) {
1039 		STAT_INCR(sync_postwrite);
1040 		return;
1041 	}
1042 	KASSERTMSG(bouncing || pre_ops != 0 || (post_ops & BUS_DMASYNC_POSTREAD),
1043 	    "pre_ops %#x post_ops %#x", pre_ops, post_ops);
1044 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1045 	if (bouncing && (ops & BUS_DMASYNC_PREWRITE)) {
1046 		struct arm32_bus_dma_cookie * const cookie = map->_dm_cookie;
1047 		STAT_INCR(write_bounces);
1048 		char * const dataptr = (char *)cookie->id_bouncebuf + offset;
1049 		/*
1050 		 * Copy the caller's buffer to the bounce buffer.
1051 		 */
1052 		switch (map->_dm_buftype) {
1053 		case _BUS_DMA_BUFTYPE_LINEAR:
1054 			memcpy(dataptr, cookie->id_origlinearbuf + offset, len);
1055 			break;
1056 		case _BUS_DMA_BUFTYPE_MBUF:
1057 			m_copydata(cookie->id_origmbuf, offset, len, dataptr);
1058 			break;
1059 		case _BUS_DMA_BUFTYPE_UIO:
1060 			_bus_dma_uiomove(dataptr, cookie->id_origuio, len, UIO_WRITE);
1061 			break;
1062 #ifdef DIAGNOSTIC
1063 		case _BUS_DMA_BUFTYPE_RAW:
1064 			panic("_bus_dmamap_sync(pre): _BUS_DMA_BUFTYPE_RAW");
1065 			break;
1066 
1067 		case _BUS_DMA_BUFTYPE_INVALID:
1068 			panic("_bus_dmamap_sync(pre): _BUS_DMA_BUFTYPE_INVALID");
1069 			break;
1070 
1071 		default:
1072 			panic("_bus_dmamap_sync(pre): map %p: unknown buffer type %d\n",
1073 			    map, map->_dm_buftype);
1074 			break;
1075 #endif /* DIAGNOSTIC */
1076 		}
1077 	}
1078 #endif /* _ARM32_NEED_BUS_DMA_BOUNCE */
1079 
1080 	/* Skip cache frobbing if mapping was COHERENT. */
1081 	if (!bouncing && (map->_dm_flags & _BUS_DMAMAP_COHERENT)) {
1082 		/* Drain the write buffer. */
1083 		if (pre_ops & BUS_DMASYNC_PREWRITE)
1084 			cpu_drain_writebuf();
1085 		return;
1086 	}
1087 
1088 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1089 	if (bouncing && ((map->_dm_flags & _BUS_DMAMAP_COHERENT) || pre_ops == 0)) {
1090 		goto bounce_it;
1091 	}
1092 #endif /* _ARM32_NEED_BUS_DMA_BOUNCE */
1093 
1094 #ifndef ARM_MMU_EXTENDED
1095 	/*
1096 	 * If the mapping belongs to a non-kernel vmspace, and the
1097 	 * vmspace has not been active since the last time a full
1098 	 * cache flush was performed, we don't need to do anything.
1099 	 */
1100 	if (__predict_false(!VMSPACE_IS_KERNEL_P(map->_dm_vmspace) &&
1101 	    vm_map_pmap(&map->_dm_vmspace->vm_map)->pm_cstate.cs_cache_d == 0))
1102 		return;
1103 #endif
1104 
1105 	int buftype = map->_dm_buftype;
1106 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1107 	if (bouncing) {
1108 		buftype = _BUS_DMA_BUFTYPE_LINEAR;
1109 	}
1110 #endif
1111 
1112 	switch (buftype) {
1113 	case _BUS_DMA_BUFTYPE_LINEAR:
1114 		_bus_dmamap_sync_linear(t, map, offset, len, ops);
1115 		break;
1116 
1117 	case _BUS_DMA_BUFTYPE_MBUF:
1118 		_bus_dmamap_sync_mbuf(t, map, offset, len, ops);
1119 		break;
1120 
1121 	case _BUS_DMA_BUFTYPE_UIO:
1122 		_bus_dmamap_sync_uio(t, map, offset, len, ops);
1123 		break;
1124 
1125 	case _BUS_DMA_BUFTYPE_RAW:
1126 		panic("_bus_dmamap_sync: _BUS_DMA_BUFTYPE_RAW");
1127 		break;
1128 
1129 	case _BUS_DMA_BUFTYPE_INVALID:
1130 		panic("_bus_dmamap_sync: _BUS_DMA_BUFTYPE_INVALID");
1131 		break;
1132 
1133 	default:
1134 		panic("_bus_dmamap_sync: map %p: unknown buffer type %d\n",
1135 		    map, map->_dm_buftype);
1136 	}
1137 
1138 	/* Drain the write buffer. */
1139 	cpu_drain_writebuf();
1140 
1141 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1142   bounce_it:
1143 	if (!bouncing || (ops & BUS_DMASYNC_POSTREAD) == 0)
1144 		return;
1145 
1146 	struct arm32_bus_dma_cookie * const cookie = map->_dm_cookie;
1147 	char * const dataptr = (char *)cookie->id_bouncebuf + offset;
1148 	STAT_INCR(read_bounces);
1149 	/*
1150 	 * Copy the bounce buffer to the caller's buffer.
1151 	 */
1152 	switch (map->_dm_buftype) {
1153 	case _BUS_DMA_BUFTYPE_LINEAR:
1154 		memcpy(cookie->id_origlinearbuf + offset, dataptr, len);
1155 		break;
1156 
1157 	case _BUS_DMA_BUFTYPE_MBUF:
1158 		m_copyback(cookie->id_origmbuf, offset, len, dataptr);
1159 		break;
1160 
1161 	case _BUS_DMA_BUFTYPE_UIO:
1162 		_bus_dma_uiomove(dataptr, cookie->id_origuio, len, UIO_READ);
1163 		break;
1164 #ifdef DIAGNOSTIC
1165 	case _BUS_DMA_BUFTYPE_RAW:
1166 		panic("_bus_dmamap_sync(post): _BUS_DMA_BUFTYPE_RAW");
1167 		break;
1168 
1169 	case _BUS_DMA_BUFTYPE_INVALID:
1170 		panic("_bus_dmamap_sync(post): _BUS_DMA_BUFTYPE_INVALID");
1171 		break;
1172 
1173 	default:
1174 		panic("_bus_dmamap_sync(post): map %p: unknown buffer type %d\n",
1175 		    map, map->_dm_buftype);
1176 		break;
1177 #endif
1178 	}
1179 #endif /* _ARM32_NEED_BUS_DMA_BOUNCE */
1180 }
1181 
1182 /*
1183  * Common function for DMA-safe memory allocation.  May be called
1184  * by bus-specific DMA memory allocation functions.
1185  */
1186 
1187 extern paddr_t physical_start;
1188 extern paddr_t physical_end;
1189 
1190 int
1191 _bus_dmamem_alloc(bus_dma_tag_t t, bus_size_t size, bus_size_t alignment,
1192     bus_size_t boundary, bus_dma_segment_t *segs, int nsegs, int *rsegs,
1193     int flags)
1194 {
1195 	struct arm32_dma_range *dr;
1196 	int error, i;
1197 
1198 #ifdef DEBUG_DMA
1199 	printf("dmamem_alloc t=%p size=%lx align=%lx boundary=%lx "
1200 	    "segs=%p nsegs=%x rsegs=%p flags=%x\n", t, size, alignment,
1201 	    boundary, segs, nsegs, rsegs, flags);
1202 #endif
1203 
1204 	if ((dr = t->_ranges) != NULL) {
1205 		error = ENOMEM;
1206 		for (i = 0; i < t->_nranges; i++, dr++) {
1207 			if (dr->dr_len == 0
1208 			    || (dr->dr_flags & _BUS_DMAMAP_NOALLOC))
1209 				continue;
1210 			error = _bus_dmamem_alloc_range(t, size, alignment,
1211 			    boundary, segs, nsegs, rsegs, flags,
1212 			    trunc_page(dr->dr_sysbase),
1213 			    trunc_page(dr->dr_sysbase + dr->dr_len));
1214 			if (error == 0)
1215 				break;
1216 		}
1217 	} else {
1218 		error = _bus_dmamem_alloc_range(t, size, alignment, boundary,
1219 		    segs, nsegs, rsegs, flags, trunc_page(physical_start),
1220 		    trunc_page(physical_end));
1221 	}
1222 
1223 #ifdef DEBUG_DMA
1224 	printf("dmamem_alloc: =%d\n", error);
1225 #endif
1226 
1227 	return(error);
1228 }
1229 
1230 /*
1231  * Common function for freeing DMA-safe memory.  May be called by
1232  * bus-specific DMA memory free functions.
1233  */
1234 void
1235 _bus_dmamem_free(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs)
1236 {
1237 	struct vm_page *m;
1238 	bus_addr_t addr;
1239 	struct pglist mlist;
1240 	int curseg;
1241 
1242 #ifdef DEBUG_DMA
1243 	printf("dmamem_free: t=%p segs=%p nsegs=%x\n", t, segs, nsegs);
1244 #endif	/* DEBUG_DMA */
1245 
1246 	/*
1247 	 * Build a list of pages to free back to the VM system.
1248 	 */
1249 	TAILQ_INIT(&mlist);
1250 	for (curseg = 0; curseg < nsegs; curseg++) {
1251 		for (addr = segs[curseg].ds_addr;
1252 		    addr < (segs[curseg].ds_addr + segs[curseg].ds_len);
1253 		    addr += PAGE_SIZE) {
1254 			m = PHYS_TO_VM_PAGE(addr);
1255 			TAILQ_INSERT_TAIL(&mlist, m, pageq.queue);
1256 		}
1257 	}
1258 	uvm_pglistfree(&mlist);
1259 }
1260 
1261 /*
1262  * Common function for mapping DMA-safe memory.  May be called by
1263  * bus-specific DMA memory map functions.
1264  */
1265 int
1266 _bus_dmamem_map(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
1267     size_t size, void **kvap, int flags)
1268 {
1269 	vaddr_t va;
1270 	paddr_t pa;
1271 	int curseg;
1272 	const uvm_flag_t kmflags = UVM_KMF_VAONLY
1273 	    | ((flags & BUS_DMA_NOWAIT) != 0 ? UVM_KMF_NOWAIT : 0);
1274 	vsize_t align = 0;
1275 
1276 #ifdef DEBUG_DMA
1277 	printf("dmamem_map: t=%p segs=%p nsegs=%x size=%lx flags=%x\n", t,
1278 	    segs, nsegs, (unsigned long)size, flags);
1279 #endif	/* DEBUG_DMA */
1280 
1281 #ifdef PMAP_MAP_POOLPAGE
1282 	/*
1283 	 * If all of memory is mapped, and we are mapping a single physically
1284 	 * contiguous area then this area is already mapped.  Let's see if we
1285 	 * avoid having a separate mapping for it.
1286 	 */
1287 	if (nsegs == 1) {
1288 		/*
1289 		 * If this is a non-COHERENT mapping, then the existing kernel
1290 		 * mapping is already compatible with it.
1291 		 */
1292 		bool direct_mapable = (flags & BUS_DMA_COHERENT) == 0;
1293 		pa = segs[0].ds_addr;
1294 
1295 		/*
1296 		 * This is a COHERENT mapping which, unless this address is in
1297 		 * a COHERENT dma range, will not be compatible.
1298 		 */
1299 		if (t->_ranges != NULL) {
1300 			const struct arm32_dma_range * const dr =
1301 			    _bus_dma_paddr_inrange(t->_ranges, t->_nranges, pa);
1302 			if (dr != NULL
1303 			    && (dr->dr_flags & _BUS_DMAMAP_COHERENT)) {
1304 				direct_mapable = true;
1305 			}
1306 		}
1307 
1308 		if (direct_mapable) {
1309 			*kvap = (void *)PMAP_MAP_POOLPAGE(pa);
1310 #ifdef DEBUG_DMA
1311 			printf("dmamem_map: =%p\n", *kvap);
1312 #endif	/* DEBUG_DMA */
1313 			return 0;
1314 		}
1315 	}
1316 #endif
1317 
1318 	size = round_page(size);
1319 	if (__predict_true(size > L2_L_SIZE)) {
1320 #if (ARM_MMU_V6 + ARM_MMU_V7) > 0
1321 		if (size >= L1_SS_SIZE)
1322 			align = L1_SS_SIZE;
1323 		else
1324 #endif
1325 		if (size >= L1_S_SIZE)
1326 			align = L1_S_SIZE;
1327 		else
1328 			align = L2_L_SIZE;
1329 	}
1330 
1331 	va = uvm_km_alloc(kernel_map, size, align, kmflags);
1332 	if (__predict_false(va == 0 && align > 0)) {
1333 		align = 0;
1334 		va = uvm_km_alloc(kernel_map, size, 0, kmflags);
1335 	}
1336 
1337 	if (va == 0)
1338 		return (ENOMEM);
1339 
1340 	*kvap = (void *)va;
1341 
1342 	for (curseg = 0; curseg < nsegs; curseg++) {
1343 		for (pa = segs[curseg].ds_addr;
1344 		    pa < (segs[curseg].ds_addr + segs[curseg].ds_len);
1345 		    pa += PAGE_SIZE, va += PAGE_SIZE, size -= PAGE_SIZE) {
1346 			bool uncached = (flags & BUS_DMA_COHERENT);
1347 #ifdef DEBUG_DMA
1348 			printf("wiring p%lx to v%lx", pa, va);
1349 #endif	/* DEBUG_DMA */
1350 			if (size == 0)
1351 				panic("_bus_dmamem_map: size botch");
1352 
1353 			const struct arm32_dma_range * const dr =
1354 			    _bus_dma_paddr_inrange(t->_ranges, t->_nranges, pa);
1355 			/*
1356 			 * If this dma region is coherent then there is
1357 			 * no need for an uncached mapping.
1358 			 */
1359 			if (dr != NULL
1360 			    && (dr->dr_flags & _BUS_DMAMAP_COHERENT)) {
1361 				uncached = false;
1362 			}
1363 
1364 			pmap_kenter_pa(va, pa, VM_PROT_READ | VM_PROT_WRITE,
1365 			    PMAP_WIRED | (uncached ? PMAP_NOCACHE : 0));
1366 		}
1367 	}
1368 	pmap_update(pmap_kernel());
1369 #ifdef DEBUG_DMA
1370 	printf("dmamem_map: =%p\n", *kvap);
1371 #endif	/* DEBUG_DMA */
1372 	return (0);
1373 }
1374 
1375 /*
1376  * Common function for unmapping DMA-safe memory.  May be called by
1377  * bus-specific DMA memory unmapping functions.
1378  */
1379 void
1380 _bus_dmamem_unmap(bus_dma_tag_t t, void *kva, size_t size)
1381 {
1382 
1383 #ifdef DEBUG_DMA
1384 	printf("dmamem_unmap: t=%p kva=%p size=%zx\n", t, kva, size);
1385 #endif	/* DEBUG_DMA */
1386 	KASSERTMSG(((uintptr_t)kva & PAGE_MASK) == 0,
1387 	    "kva %p (%#"PRIxPTR")", kva, ((uintptr_t)kva & PAGE_MASK));
1388 
1389 #ifdef __HAVE_MM_MD_DIRECT_MAPPED_PHYS
1390 	/*
1391 	 * Check to see if this used direct mapped memory.  Get it's physical
1392 	 * address and try to map it.  If the resultant matches the kva, then
1393 	 * it was and so we can just return since we have notice to free up.
1394 	 */
1395 	paddr_t pa;
1396 	vaddr_t va;
1397 	(void)pmap_extract(pmap_kernel(), (vaddr_t)kva, &pa);
1398 	if (mm_md_direct_mapped_phys(pa, &va) && va == (vaddr_t)kva)
1399 		return;
1400 #endif
1401 
1402 	size = round_page(size);
1403 	pmap_kremove((vaddr_t)kva, size);
1404 	pmap_update(pmap_kernel());
1405 	uvm_km_free(kernel_map, (vaddr_t)kva, size, UVM_KMF_VAONLY);
1406 }
1407 
1408 /*
1409  * Common functin for mmap(2)'ing DMA-safe memory.  May be called by
1410  * bus-specific DMA mmap(2)'ing functions.
1411  */
1412 paddr_t
1413 _bus_dmamem_mmap(bus_dma_tag_t t, bus_dma_segment_t *segs, int nsegs,
1414     off_t off, int prot, int flags)
1415 {
1416 	paddr_t map_flags;
1417 	int i;
1418 
1419 	for (i = 0; i < nsegs; i++) {
1420 		KASSERTMSG((off & PAGE_MASK) == 0,
1421 		    "off %#qx (%#x)", off, (int)off & PAGE_MASK);
1422 		KASSERTMSG((segs[i].ds_addr & PAGE_MASK) == 0,
1423 		    "ds_addr %#lx (%#x)", segs[i].ds_addr,
1424 		    (int)segs[i].ds_addr & PAGE_MASK);
1425 		KASSERTMSG((segs[i].ds_len & PAGE_MASK) == 0,
1426 		    "ds_len %#lx (%#x)", segs[i].ds_addr,
1427 		    (int)segs[i].ds_addr & PAGE_MASK);
1428 		if (off >= segs[i].ds_len) {
1429 			off -= segs[i].ds_len;
1430 			continue;
1431 		}
1432 
1433 		map_flags = 0;
1434 		if (flags & BUS_DMA_PREFETCHABLE)
1435 			map_flags |= ARM32_MMAP_WRITECOMBINE;
1436 
1437 		return (arm_btop((u_long)segs[i].ds_addr + off) | map_flags);
1438 
1439 	}
1440 
1441 	/* Page not found. */
1442 	return (-1);
1443 }
1444 
1445 /**********************************************************************
1446  * DMA utility functions
1447  **********************************************************************/
1448 
1449 /*
1450  * Utility function to load a linear buffer.  lastaddrp holds state
1451  * between invocations (for multiple-buffer loads).  segp contains
1452  * the starting segment on entrace, and the ending segment on exit.
1453  * first indicates if this is the first invocation of this function.
1454  */
1455 int
1456 _bus_dmamap_load_buffer(bus_dma_tag_t t, bus_dmamap_t map, void *buf,
1457     bus_size_t buflen, struct vmspace *vm, int flags)
1458 {
1459 	bus_size_t sgsize;
1460 	bus_addr_t curaddr;
1461 	vaddr_t vaddr = (vaddr_t)buf;
1462 	int error;
1463 	pmap_t pmap;
1464 
1465 #ifdef DEBUG_DMA
1466 	printf("_bus_dmamem_load_buffer(buf=%p, len=%lx, flags=%d)\n",
1467 	    buf, buflen, flags);
1468 #endif	/* DEBUG_DMA */
1469 
1470 	pmap = vm_map_pmap(&vm->vm_map);
1471 
1472 	while (buflen > 0) {
1473 		/*
1474 		 * Get the physical address for this segment.
1475 		 *
1476 		 * XXX Doesn't support checking for coherent mappings
1477 		 * XXX in user address space.
1478 		 */
1479 		bool coherent;
1480 		if (__predict_true(pmap == pmap_kernel())) {
1481 			pd_entry_t *pde;
1482 			pt_entry_t *ptep;
1483 			(void) pmap_get_pde_pte(pmap, vaddr, &pde, &ptep);
1484 			if (__predict_false(pmap_pde_section(pde))) {
1485 				paddr_t s_frame = L1_S_FRAME;
1486 				paddr_t s_offset = L1_S_OFFSET;
1487 #if (ARM_MMU_V6 + ARM_MMU_V7) > 0
1488 				if (__predict_false(pmap_pde_supersection(pde))) {
1489 					s_frame = L1_SS_FRAME;
1490 					s_offset = L1_SS_OFFSET;
1491 				}
1492 #endif
1493 				curaddr = (*pde & s_frame) | (vaddr & s_offset);
1494 				coherent = (*pde & L1_S_CACHE_MASK) == 0;
1495 			} else {
1496 				pt_entry_t pte = *ptep;
1497 				KDASSERTMSG((pte & L2_TYPE_MASK) != L2_TYPE_INV,
1498 				    "va=%#"PRIxVADDR" pde=%#x ptep=%p pte=%#x",
1499 				    vaddr, *pde, ptep, pte);
1500 				if (__predict_false((pte & L2_TYPE_MASK)
1501 						    == L2_TYPE_L)) {
1502 					curaddr = (pte & L2_L_FRAME) |
1503 					    (vaddr & L2_L_OFFSET);
1504 					coherent = (pte & L2_L_CACHE_MASK) == 0;
1505 				} else {
1506 					curaddr = (pte & ~PAGE_MASK) |
1507 					    (vaddr & PAGE_MASK);
1508 					coherent = (pte & L2_S_CACHE_MASK) == 0;
1509 				}
1510 			}
1511 		} else {
1512 			(void) pmap_extract(pmap, vaddr, &curaddr);
1513 			coherent = false;
1514 		}
1515 		KASSERTMSG((vaddr & PAGE_MASK) == (curaddr & PAGE_MASK),
1516 		    "va %#lx curaddr %#lx", vaddr, curaddr);
1517 
1518 		/*
1519 		 * Compute the segment size, and adjust counts.
1520 		 */
1521 		sgsize = PAGE_SIZE - ((u_long)vaddr & PGOFSET);
1522 		if (buflen < sgsize)
1523 			sgsize = buflen;
1524 
1525 		error = _bus_dmamap_load_paddr(t, map, curaddr, sgsize,
1526 		    coherent);
1527 		if (error)
1528 			return (error);
1529 
1530 		vaddr += sgsize;
1531 		buflen -= sgsize;
1532 	}
1533 
1534 	return (0);
1535 }
1536 
1537 /*
1538  * Allocate physical memory from the given physical address range.
1539  * Called by DMA-safe memory allocation methods.
1540  */
1541 int
1542 _bus_dmamem_alloc_range(bus_dma_tag_t t, bus_size_t size, bus_size_t alignment,
1543     bus_size_t boundary, bus_dma_segment_t *segs, int nsegs, int *rsegs,
1544     int flags, paddr_t low, paddr_t high)
1545 {
1546 	paddr_t curaddr, lastaddr;
1547 	struct vm_page *m;
1548 	struct pglist mlist;
1549 	int curseg, error;
1550 
1551 	KASSERTMSG(boundary == 0 || (boundary & (boundary-1)) == 0,
1552 	    "invalid boundary %#lx", boundary);
1553 
1554 #ifdef DEBUG_DMA
1555 	printf("alloc_range: t=%p size=%lx align=%lx boundary=%lx segs=%p nsegs=%x rsegs=%p flags=%x lo=%lx hi=%lx\n",
1556 	    t, size, alignment, boundary, segs, nsegs, rsegs, flags, low, high);
1557 #endif	/* DEBUG_DMA */
1558 
1559 	/* Always round the size. */
1560 	size = round_page(size);
1561 
1562 	/*
1563 	 * We accept boundaries < size, splitting in multiple segments
1564 	 * if needed. uvm_pglistalloc does not, so compute an appropriate
1565 	 * boundary: next power of 2 >= size
1566 	 */
1567 	bus_size_t uboundary = boundary;
1568 	if (uboundary <= PAGE_SIZE) {
1569 		uboundary = 0;
1570 	} else {
1571 		while (uboundary < size) {
1572 			uboundary <<= 1;
1573 		}
1574 	}
1575 
1576 	/*
1577 	 * Allocate pages from the VM system.
1578 	 */
1579 	error = uvm_pglistalloc(size, low, high, alignment, uboundary,
1580 	    &mlist, nsegs, (flags & BUS_DMA_NOWAIT) == 0);
1581 	if (error)
1582 		return (error);
1583 
1584 	/*
1585 	 * Compute the location, size, and number of segments actually
1586 	 * returned by the VM code.
1587 	 */
1588 	m = TAILQ_FIRST(&mlist);
1589 	curseg = 0;
1590 	lastaddr = segs[curseg].ds_addr = VM_PAGE_TO_PHYS(m);
1591 	segs[curseg].ds_len = PAGE_SIZE;
1592 #ifdef DEBUG_DMA
1593 		printf("alloc: page %lx\n", lastaddr);
1594 #endif	/* DEBUG_DMA */
1595 	m = TAILQ_NEXT(m, pageq.queue);
1596 
1597 	for (; m != NULL; m = TAILQ_NEXT(m, pageq.queue)) {
1598 		curaddr = VM_PAGE_TO_PHYS(m);
1599 		KASSERTMSG(low <= curaddr && curaddr < high,
1600 		    "uvm_pglistalloc returned non-sensicaladdress %#lx "
1601 		    "(low=%#lx, high=%#lx\n", curaddr, low, high);
1602 #ifdef DEBUG_DMA
1603 		printf("alloc: page %lx\n", curaddr);
1604 #endif	/* DEBUG_DMA */
1605 		if (curaddr == lastaddr + PAGE_SIZE
1606 		    && (lastaddr & boundary) == (curaddr & boundary))
1607 			segs[curseg].ds_len += PAGE_SIZE;
1608 		else {
1609 			curseg++;
1610 			if (curseg >= nsegs) {
1611 				uvm_pglistfree(&mlist);
1612 				return EFBIG;
1613 			}
1614 			segs[curseg].ds_addr = curaddr;
1615 			segs[curseg].ds_len = PAGE_SIZE;
1616 		}
1617 		lastaddr = curaddr;
1618 	}
1619 
1620 	*rsegs = curseg + 1;
1621 
1622 	return (0);
1623 }
1624 
1625 /*
1626  * Check if a memory region intersects with a DMA range, and return the
1627  * page-rounded intersection if it does.
1628  */
1629 int
1630 arm32_dma_range_intersect(struct arm32_dma_range *ranges, int nranges,
1631     paddr_t pa, psize_t size, paddr_t *pap, psize_t *sizep)
1632 {
1633 	struct arm32_dma_range *dr;
1634 	int i;
1635 
1636 	if (ranges == NULL)
1637 		return (0);
1638 
1639 	for (i = 0, dr = ranges; i < nranges; i++, dr++) {
1640 		if (dr->dr_sysbase <= pa &&
1641 		    pa < (dr->dr_sysbase + dr->dr_len)) {
1642 			/*
1643 			 * Beginning of region intersects with this range.
1644 			 */
1645 			*pap = trunc_page(pa);
1646 			*sizep = round_page(min(pa + size,
1647 			    dr->dr_sysbase + dr->dr_len) - pa);
1648 			return (1);
1649 		}
1650 		if (pa < dr->dr_sysbase && dr->dr_sysbase < (pa + size)) {
1651 			/*
1652 			 * End of region intersects with this range.
1653 			 */
1654 			*pap = trunc_page(dr->dr_sysbase);
1655 			*sizep = round_page(min((pa + size) - dr->dr_sysbase,
1656 			    dr->dr_len));
1657 			return (1);
1658 		}
1659 	}
1660 
1661 	/* No intersection found. */
1662 	return (0);
1663 }
1664 
1665 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1666 static int
1667 _bus_dma_alloc_bouncebuf(bus_dma_tag_t t, bus_dmamap_t map,
1668     bus_size_t size, int flags)
1669 {
1670 	struct arm32_bus_dma_cookie *cookie = map->_dm_cookie;
1671 	int error = 0;
1672 
1673 	KASSERT(cookie != NULL);
1674 
1675 	cookie->id_bouncebuflen = round_page(size);
1676 	error = _bus_dmamem_alloc(t, cookie->id_bouncebuflen,
1677 	    PAGE_SIZE, map->_dm_boundary, cookie->id_bouncesegs,
1678 	    map->_dm_segcnt, &cookie->id_nbouncesegs, flags);
1679 	if (error == 0) {
1680 		error = _bus_dmamem_map(t, cookie->id_bouncesegs,
1681 		    cookie->id_nbouncesegs, cookie->id_bouncebuflen,
1682 		    (void **)&cookie->id_bouncebuf, flags);
1683 		if (error) {
1684 			_bus_dmamem_free(t, cookie->id_bouncesegs,
1685 			    cookie->id_nbouncesegs);
1686 			cookie->id_bouncebuflen = 0;
1687 			cookie->id_nbouncesegs = 0;
1688 		} else {
1689 			cookie->id_flags |= _BUS_DMA_HAS_BOUNCE;
1690 		}
1691 	} else {
1692 		cookie->id_bouncebuflen = 0;
1693 		cookie->id_nbouncesegs = 0;
1694 	}
1695 
1696 	return (error);
1697 }
1698 
1699 static void
1700 _bus_dma_free_bouncebuf(bus_dma_tag_t t, bus_dmamap_t map)
1701 {
1702 	struct arm32_bus_dma_cookie *cookie = map->_dm_cookie;
1703 
1704 	KASSERT(cookie != NULL);
1705 
1706 	_bus_dmamem_unmap(t, cookie->id_bouncebuf, cookie->id_bouncebuflen);
1707 	_bus_dmamem_free(t, cookie->id_bouncesegs, cookie->id_nbouncesegs);
1708 	cookie->id_bouncebuflen = 0;
1709 	cookie->id_nbouncesegs = 0;
1710 	cookie->id_flags &= ~_BUS_DMA_HAS_BOUNCE;
1711 }
1712 
1713 /*
1714  * This function does the same as uiomove, but takes an explicit
1715  * direction, and does not update the uio structure.
1716  */
1717 static int
1718 _bus_dma_uiomove(void *buf, struct uio *uio, size_t n, int direction)
1719 {
1720 	struct iovec *iov;
1721 	int error;
1722 	struct vmspace *vm;
1723 	char *cp;
1724 	size_t resid, cnt;
1725 	int i;
1726 
1727 	iov = uio->uio_iov;
1728 	vm = uio->uio_vmspace;
1729 	cp = buf;
1730 	resid = n;
1731 
1732 	for (i = 0; i < uio->uio_iovcnt && resid > 0; i++) {
1733 		iov = &uio->uio_iov[i];
1734 		if (iov->iov_len == 0)
1735 			continue;
1736 		cnt = MIN(resid, iov->iov_len);
1737 
1738 		if (!VMSPACE_IS_KERNEL_P(vm) &&
1739 		    (curlwp->l_cpu->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
1740 		    != 0) {
1741 			preempt();
1742 		}
1743 		if (direction == UIO_READ) {
1744 			error = copyout_vmspace(vm, cp, iov->iov_base, cnt);
1745 		} else {
1746 			error = copyin_vmspace(vm, iov->iov_base, cp, cnt);
1747 		}
1748 		if (error)
1749 			return (error);
1750 		cp += cnt;
1751 		resid -= cnt;
1752 	}
1753 	return (0);
1754 }
1755 #endif /* _ARM32_NEED_BUS_DMA_BOUNCE */
1756 
1757 int
1758 _bus_dmatag_subregion(bus_dma_tag_t tag, bus_addr_t min_addr,
1759     bus_addr_t max_addr, bus_dma_tag_t *newtag, int flags)
1760 {
1761 
1762 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1763 	struct arm32_dma_range *dr;
1764 	bool subset = false;
1765 	size_t nranges = 0;
1766 	size_t i;
1767 	for (i = 0, dr = tag->_ranges; i < tag->_nranges; i++, dr++) {
1768 		if (dr->dr_sysbase <= min_addr
1769 		    && max_addr <= dr->dr_sysbase + dr->dr_len - 1) {
1770 			subset = true;
1771 		}
1772 		if (min_addr <= dr->dr_sysbase + dr->dr_len
1773 		    && max_addr >= dr->dr_sysbase) {
1774 			nranges++;
1775 		}
1776 	}
1777 	if (subset) {
1778 		*newtag = tag;
1779 		/* if the tag must be freed, add a reference */
1780 		if (tag->_tag_needs_free)
1781 			(tag->_tag_needs_free)++;
1782 		return 0;
1783 	}
1784 	if (nranges == 0) {
1785 		nranges = 1;
1786 	}
1787 
1788 	const size_t tagsize = sizeof(*tag) + nranges * sizeof(*dr);
1789 	if ((*newtag = kmem_intr_zalloc(tagsize,
1790 	    (flags & BUS_DMA_NOWAIT) ? KM_NOSLEEP : KM_SLEEP)) == NULL)
1791 		return ENOMEM;
1792 
1793 	dr = (void *)(*newtag + 1);
1794 	**newtag = *tag;
1795 	(*newtag)->_tag_needs_free = 1;
1796 	(*newtag)->_ranges = dr;
1797 	(*newtag)->_nranges = nranges;
1798 
1799 	if (tag->_ranges == NULL) {
1800 		dr->dr_sysbase = min_addr;
1801 		dr->dr_busbase = min_addr;
1802 		dr->dr_len = max_addr + 1 - min_addr;
1803 	} else {
1804 		for (i = 0; i < nranges; i++) {
1805 			if (min_addr > dr->dr_sysbase + dr->dr_len
1806 			    || max_addr < dr->dr_sysbase)
1807 				continue;
1808 			dr[0] = tag->_ranges[i];
1809 			if (dr->dr_sysbase < min_addr) {
1810 				psize_t diff = min_addr - dr->dr_sysbase;
1811 				dr->dr_busbase += diff;
1812 				dr->dr_len -= diff;
1813 				dr->dr_sysbase += diff;
1814 			}
1815 			if (max_addr != 0xffffffff
1816 			    && max_addr + 1 < dr->dr_sysbase + dr->dr_len) {
1817 				dr->dr_len = max_addr + 1 - dr->dr_sysbase;
1818 			}
1819 			dr++;
1820 		}
1821 	}
1822 
1823 	return 0;
1824 #else
1825 	return EOPNOTSUPP;
1826 #endif /* _ARM32_NEED_BUS_DMA_BOUNCE */
1827 }
1828 
1829 void
1830 _bus_dmatag_destroy(bus_dma_tag_t tag)
1831 {
1832 #ifdef _ARM32_NEED_BUS_DMA_BOUNCE
1833 	switch (tag->_tag_needs_free) {
1834 	case 0:
1835 		break;				/* not allocated with kmem */
1836 	case 1: {
1837 		const size_t tagsize = sizeof(*tag)
1838 		    + tag->_nranges * sizeof(*tag->_ranges);
1839 		kmem_intr_free(tag, tagsize);	/* last reference to tag */
1840 		break;
1841 	}
1842 	default:
1843 		(tag->_tag_needs_free)--;	/* one less reference */
1844 	}
1845 #endif
1846 }
1847