busdma: Add PROTECTED bus_dma_tag_create() flag.
[dragonfly.git] / sys / platform / pc32 / i386 / busdma_machdep.c
1 /*
2  * Copyright (c) 1997, 1998 Justin T. Gibbs.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions, and the following disclaimer,
10  *    without modification, immediately at the beginning of the file.
11  * 2. The name of the author may not be used to endorse or promote products
12  *    derived from this software without specific prior written permission.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
18  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD: src/sys/i386/i386/busdma_machdep.c,v 1.94 2008/08/15 20:51:31 kmacy Exp $
27  * $DragonFly: src/sys/platform/pc32/i386/busdma_machdep.c,v 1.23 2008/06/05 18:06:32 swildner Exp $
28  */
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/malloc.h>
33 #include <sys/mbuf.h>
34 #include <sys/uio.h>
35 #include <sys/bus_dma.h>
36 #include <sys/kernel.h>
37 #include <sys/sysctl.h>
38 #include <sys/lock.h>
39
40 #include <sys/thread2.h>
41 #include <sys/spinlock2.h>
42 #include <sys/mplock2.h>
43
44 #include <vm/vm.h>
45 #include <vm/vm_page.h>
46
47 /* XXX needed for to access pmap to convert per-proc virtual to physical */
48 #include <sys/proc.h>
49 #include <sys/lock.h>
50 #include <vm/vm_map.h>
51
52 #include <machine/md_var.h>
53
54 #define MAX_BPAGES      1024
55
56 /*
57  * 16 x N declared on stack.
58  */
59 #define BUS_DMA_CACHE_SEGMENTS  8
60
61 struct bounce_zone;
62 struct bus_dmamap;
63
64 struct bus_dma_tag {
65         bus_dma_tag_t   parent;
66         bus_size_t      alignment;
67         bus_size_t      boundary;
68         bus_addr_t      lowaddr;
69         bus_addr_t      highaddr;
70         bus_dma_filter_t *filter;
71         void            *filterarg;
72         bus_size_t      maxsize;
73         u_int           nsegments;
74         bus_size_t      maxsegsz;
75         int             flags;
76         int             ref_count;
77         int             map_count;
78         bus_dma_segment_t *segments;
79         struct bounce_zone *bounce_zone;
80 #ifdef SMP
81         struct spinlock spin;
82 #else
83         int             unused0;
84 #endif
85 };
86
87 /*
88  * bus_dma_tag private flags
89  */
90 #define BUS_DMA_BOUNCE_ALIGN    BUS_DMA_BUS2
91 #define BUS_DMA_BOUNCE_LOWADDR  BUS_DMA_BUS3
92 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
93
94 #define BUS_DMA_COULD_BOUNCE    (BUS_DMA_BOUNCE_LOWADDR | BUS_DMA_BOUNCE_ALIGN)
95
96 #define BUS_DMAMEM_KMALLOC(dmat) \
97         ((dmat)->maxsize <= PAGE_SIZE && \
98          (dmat)->alignment <= PAGE_SIZE && \
99          (dmat)->lowaddr >= ptoa(Maxmem))
100
101 struct bounce_page {
102         vm_offset_t     vaddr;          /* kva of bounce buffer */
103         bus_addr_t      busaddr;        /* Physical address */
104         vm_offset_t     datavaddr;      /* kva of client data */
105         bus_size_t      datacount;      /* client data count */
106         STAILQ_ENTRY(bounce_page) links;
107 };
108
109 struct bounce_zone {
110         STAILQ_ENTRY(bounce_zone) links;
111         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
112         STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
113 #ifdef SMP
114         struct spinlock spin;
115 #else
116         int             unused0;
117 #endif
118         int             total_bpages;
119         int             free_bpages;
120         int             reserved_bpages;
121         int             active_bpages;
122         int             total_bounced;
123         int             total_deferred;
124         int             reserve_failed;
125         bus_size_t      alignment;
126         bus_addr_t      lowaddr;
127         char            zoneid[8];
128         char            lowaddrid[20];
129         struct sysctl_ctx_list sysctl_ctx;
130         struct sysctl_oid *sysctl_tree;
131 };
132
133 #ifdef SMP
134 #define BZ_LOCK(bz)     spin_lock(&(bz)->spin)
135 #define BZ_UNLOCK(bz)   spin_unlock(&(bz)->spin)
136 #else
137 #define BZ_LOCK(bz)     crit_enter()
138 #define BZ_UNLOCK(bz)   crit_exit()
139 #endif
140
141 static struct lwkt_token bounce_zone_tok =
142         LWKT_TOKEN_MP_INITIALIZER(bounce_zone_tok);
143 static int busdma_zonecount;
144 static STAILQ_HEAD(, bounce_zone) bounce_zone_list =
145         STAILQ_HEAD_INITIALIZER(bounce_zone_list);
146
147 static int busdma_priv_zonecount = -1;
148
149 int busdma_swi_pending;
150 static int total_bounce_pages;
151 static int max_bounce_pages = MAX_BPAGES;
152 static int bounce_alignment = 1; /* XXX temporary */
153
154 TUNABLE_INT("hw.busdma.max_bpages", &max_bounce_pages);
155 TUNABLE_INT("hw.busdma.bounce_alignment", &bounce_alignment);
156
157 struct bus_dmamap {
158         struct bp_list  bpages;
159         int             pagesneeded;
160         int             pagesreserved;
161         bus_dma_tag_t   dmat;
162         void            *buf;           /* unmapped buffer pointer */
163         bus_size_t      buflen;         /* unmapped buffer length */
164         bus_dmamap_callback_t *callback;
165         void            *callback_arg;
166         STAILQ_ENTRY(bus_dmamap) links;
167 };
168
169 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist =
170         STAILQ_HEAD_INITIALIZER(bounce_map_callbacklist);
171 static struct spinlock bounce_map_list_spin =
172         SPINLOCK_INITIALIZER(&bounce_map_list_spin);
173
174 static struct bus_dmamap nobounce_dmamap;
175
176 static int              alloc_bounce_zone(bus_dma_tag_t);
177 static int              alloc_bounce_pages(bus_dma_tag_t, u_int, int);
178 static void             free_bounce_pages_all(bus_dma_tag_t);
179 static void             free_bounce_zone(bus_dma_tag_t);
180 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
181 static void             return_bounce_pages(bus_dma_tag_t, bus_dmamap_t);
182 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
183                             vm_offset_t, bus_size_t);
184 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
185
186 static bus_dmamap_t     get_map_waiting(bus_dma_tag_t);
187 static void             add_map_callback(bus_dmamap_t);
188
189 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
190 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bounce_pages,
191            0, "Total bounce pages");
192 SYSCTL_INT(_hw_busdma, OID_AUTO, max_bpages, CTLFLAG_RD, &max_bounce_pages,
193            0, "Max bounce pages per bounce zone");
194 SYSCTL_INT(_hw_busdma, OID_AUTO, bounce_alignment, CTLFLAG_RD,
195            &bounce_alignment, 0, "Obey alignment constraint");
196
197 static __inline int
198 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
199 {
200         int retval;
201
202         retval = 0;
203         do {
204                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr) ||
205                      (bounce_alignment && (paddr & (dmat->alignment - 1)) != 0))
206                  && (dmat->filter == NULL ||
207                      dmat->filter(dmat->filterarg, paddr) != 0))
208                         retval = 1;
209
210                 dmat = dmat->parent;
211         } while (retval == 0 && dmat != NULL);
212         return (retval);
213 }
214
215 static __inline
216 bus_dma_segment_t *
217 bus_dma_tag_lock(bus_dma_tag_t tag, bus_dma_segment_t *cache)
218 {
219         if (tag->flags & BUS_DMA_PROTECTED)
220                 return(tag->segments);
221
222         if (tag->nsegments <= BUS_DMA_CACHE_SEGMENTS)
223                 return(cache);
224 #ifdef SMP
225         spin_lock(&tag->spin);
226 #endif
227         return(tag->segments);
228 }
229
230 static __inline
231 void
232 bus_dma_tag_unlock(bus_dma_tag_t tag)
233 {
234 #ifdef SMP
235         if (tag->flags & BUS_DMA_PROTECTED)
236                 return;
237
238         if (tag->nsegments > BUS_DMA_CACHE_SEGMENTS)
239                 spin_unlock(&tag->spin);
240 #endif
241 }
242
243 /*
244  * Allocate a device specific dma_tag.
245  */
246 int
247 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
248                    bus_size_t boundary, bus_addr_t lowaddr,
249                    bus_addr_t highaddr, bus_dma_filter_t *filter,
250                    void *filterarg, bus_size_t maxsize, int nsegments,
251                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
252 {
253         bus_dma_tag_t newtag;
254         int error = 0;
255
256         /*
257          * Sanity checks
258          */
259
260         if (alignment == 0)
261                 alignment = 1;
262         if (alignment & (alignment - 1))
263                 panic("alignment must be power of 2\n");
264
265         if (boundary != 0) {
266                 if (boundary & (boundary - 1))
267                         panic("boundary must be power of 2\n");
268                 if (boundary < maxsegsz) {
269                         kprintf("boundary < maxsegsz:\n");
270                         print_backtrace(-1);
271                         maxsegsz = boundary;
272                 }
273         }
274
275         /* Return a NULL tag on failure */
276         *dmat = NULL;
277
278         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT | M_ZERO);
279
280 #ifdef SMP
281         spin_init(&newtag->spin);
282 #endif
283         newtag->parent = parent;
284         newtag->alignment = alignment;
285         newtag->boundary = boundary;
286         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
287         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
288         newtag->filter = filter;
289         newtag->filterarg = filterarg;
290         newtag->maxsize = maxsize;
291         newtag->nsegments = nsegments;
292         newtag->maxsegsz = maxsegsz;
293         newtag->flags = flags;
294         newtag->ref_count = 1; /* Count ourself */
295         newtag->map_count = 0;
296         newtag->segments = NULL;
297         newtag->bounce_zone = NULL;
298
299         /* Take into account any restrictions imposed by our parent tag */
300         if (parent != NULL) {
301                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
302                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
303
304                 if (newtag->boundary == 0) {
305                         newtag->boundary = parent->boundary;
306                 } else if (parent->boundary != 0) {
307                         newtag->boundary = MIN(parent->boundary,
308                                                newtag->boundary);
309                 }
310
311 #ifdef notyet
312                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
313 #endif
314
315                 if (newtag->filter == NULL) {
316                         /*
317                          * Short circuit looking at our parent directly
318                          * since we have encapsulated all of its information
319                          */
320                         newtag->filter = parent->filter;
321                         newtag->filterarg = parent->filterarg;
322                         newtag->parent = parent->parent;
323                 }
324                 if (newtag->parent != NULL)
325                         parent->ref_count++;
326         }
327
328         if (newtag->lowaddr < ptoa(Maxmem))
329                 newtag->flags |= BUS_DMA_BOUNCE_LOWADDR;
330         if (bounce_alignment && newtag->alignment > 1 &&
331             !(newtag->flags & BUS_DMA_ALIGNED))
332                 newtag->flags |= BUS_DMA_BOUNCE_ALIGN;
333
334         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
335             (flags & BUS_DMA_ALLOCNOW) != 0) {
336                 struct bounce_zone *bz;
337
338                 /* Must bounce */
339
340                 error = alloc_bounce_zone(newtag);
341                 if (error)
342                         goto back;
343                 bz = newtag->bounce_zone;
344
345                 if ((newtag->flags & BUS_DMA_ALLOCALL) == 0 &&
346                     ptoa(bz->total_bpages) < maxsize) {
347                         int pages;
348
349                         if (flags & BUS_DMA_ONEBPAGE) {
350                                 pages = 1;
351                         } else {
352                                 pages = atop(round_page(maxsize)) -
353                                         bz->total_bpages;
354                                 pages = MAX(pages, 1);
355                         }
356
357                         /* Add pages to our bounce pool */
358                         if (alloc_bounce_pages(newtag, pages, flags) < pages)
359                                 error = ENOMEM;
360
361                         /* Performed initial allocation */
362                         newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
363                 }
364         }
365 back:
366         if (error)
367                 kfree(newtag, M_DEVBUF);
368         else
369                 *dmat = newtag;
370         return error;
371 }
372
373 int
374 bus_dma_tag_destroy(bus_dma_tag_t dmat)
375 {
376         if (dmat != NULL) {
377                 if (dmat->map_count != 0)
378                         return (EBUSY);
379
380                 while (dmat != NULL) {
381                         bus_dma_tag_t parent;
382
383                         parent = dmat->parent;
384                         dmat->ref_count--;
385                         if (dmat->ref_count == 0) {
386                                 free_bounce_zone(dmat);
387                                 if (dmat->segments != NULL)
388                                         kfree(dmat->segments, M_DEVBUF);
389                                 kfree(dmat, M_DEVBUF);
390                                 /*
391                                  * Last reference count, so
392                                  * release our reference
393                                  * count on our parent.
394                                  */
395                                 dmat = parent;
396                         } else
397                                 dmat = NULL;
398                 }
399         }
400         return (0);
401 }
402
403 bus_size_t
404 bus_dma_tag_getmaxsize(bus_dma_tag_t tag)
405 {
406         return(tag->maxsize);
407 }
408
409 /*
410  * Allocate a handle for mapping from kva/uva/physical
411  * address space into bus device space.
412  */
413 int
414 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
415 {
416         int error;
417
418         error = 0;
419
420         if (dmat->segments == NULL) {
421                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
422                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) * 
423                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
424         }
425
426         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
427                 struct bounce_zone *bz;
428                 int maxpages;
429
430                 /* Must bounce */
431
432                 if (dmat->bounce_zone == NULL) {
433                         error = alloc_bounce_zone(dmat);
434                         if (error)
435                                 return error;
436                 }
437                 bz = dmat->bounce_zone;
438
439                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
440
441                 /* Initialize the new map */
442                 STAILQ_INIT(&((*mapp)->bpages));
443
444                 /*
445                  * Attempt to add pages to our pool on a per-instance
446                  * basis up to a sane limit.
447                  */
448                 if (dmat->flags & BUS_DMA_ALLOCALL) {
449                         maxpages = Maxmem - atop(dmat->lowaddr);
450                 } else if (dmat->flags & BUS_DMA_BOUNCE_ALIGN) {
451                         maxpages = max_bounce_pages;
452                 } else {
453                         maxpages = MIN(max_bounce_pages,
454                                        Maxmem - atop(dmat->lowaddr));
455                 }
456                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0 ||
457                     (dmat->map_count > 0 && bz->total_bpages < maxpages)) {
458                         int pages;
459
460                         if (flags & BUS_DMA_ONEBPAGE) {
461                                 pages = 1;
462                         } else {
463                                 pages = atop(round_page(dmat->maxsize));
464                                 pages = MIN(maxpages - bz->total_bpages, pages);
465                                 pages = MAX(pages, 1);
466                         }
467                         if (alloc_bounce_pages(dmat, pages, flags) < pages)
468                                 error = ENOMEM;
469
470                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
471                                 if (!error &&
472                                     (dmat->flags & BUS_DMA_ALLOCALL) == 0)
473                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
474                         } else {
475                                 error = 0;
476                         }
477                 }
478         } else {
479                 *mapp = NULL;
480         }
481         if (!error)
482                 dmat->map_count++;
483         return error;
484 }
485
486 /*
487  * Destroy a handle for mapping from kva/uva/physical
488  * address space into bus device space.
489  */
490 int
491 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
492 {
493         if (map != NULL) {
494                 if (STAILQ_FIRST(&map->bpages) != NULL)
495                         return (EBUSY);
496                 kfree(map, M_DEVBUF);
497         }
498         dmat->map_count--;
499         return (0);
500 }
501
502 static __inline bus_size_t
503 check_kmalloc(bus_dma_tag_t dmat, const void *vaddr0, int verify)
504 {
505         bus_size_t maxsize = 0;
506         uintptr_t vaddr = (uintptr_t)vaddr0;
507
508         if ((vaddr ^ (vaddr + dmat->maxsize - 1)) & ~PAGE_MASK) {
509                 if (verify || bootverbose)
510                         kprintf("boundary check failed\n");
511                 if (verify)
512                         print_backtrace(-1); /* XXX panic */
513                 maxsize = dmat->maxsize;
514         }
515         if (vaddr & (dmat->alignment - 1)) {
516                 if (verify || bootverbose)
517                         kprintf("alignment check failed\n");
518                 if (verify)
519                         print_backtrace(-1); /* XXX panic */
520                 if (dmat->maxsize < dmat->alignment)
521                         maxsize = dmat->alignment;
522                 else
523                         maxsize = dmat->maxsize;
524         }
525         return maxsize;
526 }
527
528 /*
529  * Allocate a piece of memory that can be efficiently mapped into
530  * bus device space based on the constraints lited in the dma tag.
531  *
532  * mapp is degenerate.  By definition this allocation should not require
533  * bounce buffers so do not allocate a dma map.
534  */
535 int
536 bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr, int flags,
537                  bus_dmamap_t *mapp)
538 {
539         int mflags;
540
541         /* If we succeed, no mapping/bouncing will be required */
542         *mapp = NULL;
543
544         if (dmat->segments == NULL) {
545                 KKASSERT(dmat->nsegments < 16384);
546                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) * 
547                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
548         }
549
550         if (flags & BUS_DMA_NOWAIT)
551                 mflags = M_NOWAIT;
552         else
553                 mflags = M_WAITOK;
554         if (flags & BUS_DMA_ZERO)
555                 mflags |= M_ZERO;
556
557         if (BUS_DMAMEM_KMALLOC(dmat)) {
558                 bus_size_t maxsize;
559
560                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
561
562                 /*
563                  * XXX
564                  * Check whether the allocation
565                  * - crossed a page boundary
566                  * - was not aligned
567                  * Retry with power-of-2 alignment in the above cases.
568                  */
569                 maxsize = check_kmalloc(dmat, *vaddr, 0);
570                 if (maxsize) {
571                         size_t size;
572
573                         kfree(*vaddr, M_DEVBUF);
574                         /* XXX check for overflow? */
575                         for (size = 1; size <= maxsize; size <<= 1)
576                                 ;
577                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
578                         check_kmalloc(dmat, *vaddr, 1);
579                 }
580         } else {
581                 /*
582                  * XXX Use Contigmalloc until it is merged into this facility
583                  *     and handles multi-seg allocations.  Nobody is doing
584                  *     multi-seg allocations yet though.
585                  */
586                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
587                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
588         }
589         if (*vaddr == NULL)
590                 return (ENOMEM);
591         return (0);
592 }
593
594 /*
595  * Free a piece of memory and it's allociated dmamap, that was allocated
596  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
597  */
598 void
599 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
600 {
601         /*
602          * dmamem does not need to be bounced, so the map should be
603          * NULL
604          */
605         if (map != NULL)
606                 panic("bus_dmamem_free: Invalid map freed\n");
607         if (BUS_DMAMEM_KMALLOC(dmat))
608                 kfree(vaddr, M_DEVBUF);
609         else
610                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
611 }
612
613 static __inline vm_paddr_t
614 _bus_dma_extract(pmap_t pmap, vm_offset_t vaddr)
615 {
616         if (pmap)
617                 return pmap_extract(pmap, vaddr);
618         else
619                 return pmap_kextract(vaddr);
620 }
621
622 /*
623  * Utility function to load a linear buffer.  lastaddrp holds state
624  * between invocations (for multiple-buffer loads).  segp contains
625  * the segment following the starting one on entrace, and the ending
626  * segment on exit.  first indicates if this is the first invocation
627  * of this function.
628  */
629 static int
630 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
631                         bus_dmamap_t map,
632                         void *buf, bus_size_t buflen,
633                         bus_dma_segment_t *segments,
634                         int nsegments,
635                         pmap_t pmap,
636                         int flags,
637                         vm_paddr_t *lastpaddrp,
638                         int *segp,
639                         int first)
640 {
641         vm_offset_t vaddr;
642         vm_paddr_t paddr, nextpaddr;
643         bus_dma_segment_t *sg;
644         bus_addr_t bmask;
645         int seg, error = 0;
646
647         if (map == NULL)
648                 map = &nobounce_dmamap;
649
650 #ifdef INVARIANTS
651         if (dmat->flags & BUS_DMA_ALIGNED)
652                 KKASSERT(((uintptr_t)buf & (dmat->alignment - 1)) == 0);
653 #endif
654
655         /*
656          * If we are being called during a callback, pagesneeded will
657          * be non-zero, so we can avoid doing the work twice.
658          */
659         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
660             map != &nobounce_dmamap && map->pagesneeded == 0) {
661                 vm_offset_t vendaddr;
662
663                 /*
664                  * Count the number of bounce pages
665                  * needed in order to complete this transfer
666                  */
667                 vaddr = (vm_offset_t)buf;
668                 vendaddr = (vm_offset_t)buf + buflen;
669
670                 while (vaddr < vendaddr) {
671                         paddr = _bus_dma_extract(pmap, vaddr);
672                         if (run_filter(dmat, paddr) != 0)
673                                 map->pagesneeded++;
674                         vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
675                 }
676         }
677
678         /* Reserve Necessary Bounce Pages */
679         if (map->pagesneeded != 0) {
680                 struct bounce_zone *bz;
681
682                 bz = dmat->bounce_zone;
683                 BZ_LOCK(bz);
684                 if (flags & BUS_DMA_NOWAIT) {
685                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
686                                 BZ_UNLOCK(bz);
687                                 error = ENOMEM;
688                                 goto free_bounce;
689                         }
690                 } else {
691                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
692                                 /* Queue us for resources */
693                                 map->dmat = dmat;
694                                 map->buf = buf;
695                                 map->buflen = buflen;
696
697                                 STAILQ_INSERT_TAIL(
698                                     &dmat->bounce_zone->bounce_map_waitinglist,
699                                     map, links);
700                                 BZ_UNLOCK(bz);
701
702                                 return (EINPROGRESS);
703                         }
704                 }
705                 BZ_UNLOCK(bz);
706         }
707
708         KKASSERT(*segp >= 1 && *segp <= nsegments);
709         seg = *segp;
710         sg = &segments[seg - 1];
711
712         vaddr = (vm_offset_t)buf;
713         nextpaddr = *lastpaddrp;
714         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
715
716         /* force at least one segment */
717         do {
718                 bus_size_t size;
719
720                 /*
721                  * Per-page main loop
722                  */
723                 paddr = _bus_dma_extract(pmap, vaddr);
724                 size = PAGE_SIZE - (paddr & PAGE_MASK);
725                 if (size > buflen)
726                         size = buflen;
727                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
728                         /*
729                          * note: this paddr has the same in-page offset
730                          * as vaddr and thus the paddr above, so the
731                          * size does not have to be recalculated
732                          */
733                         paddr = add_bounce_page(dmat, map, vaddr, size);
734                 }
735
736                 /*
737                  * Fill in the bus_dma_segment
738                  */
739                 if (first) {
740                         sg->ds_addr = paddr;
741                         sg->ds_len = size;
742                         first = 0;
743                 } else if (paddr == nextpaddr) {
744                         sg->ds_len += size;
745                 } else {
746                         sg++;
747                         seg++;
748                         if (seg > nsegments)
749                                 break;
750                         sg->ds_addr = paddr;
751                         sg->ds_len = size;
752                 }
753                 nextpaddr = paddr + size;
754
755                 /*
756                  * Handle maxsegsz and boundary issues with a nested loop
757                  */
758                 for (;;) {
759                         bus_size_t tmpsize;
760
761                         /*
762                          * Limit to the boundary and maximum segment size
763                          */
764                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
765                                 tmpsize = dmat->boundary -
766                                           (sg->ds_addr & ~bmask);
767                                 if (tmpsize > dmat->maxsegsz)
768                                         tmpsize = dmat->maxsegsz;
769                                 KKASSERT(tmpsize < sg->ds_len);
770                         } else if (sg->ds_len > dmat->maxsegsz) {
771                                 tmpsize = dmat->maxsegsz;
772                         } else {
773                                 break;
774                         }
775
776                         /*
777                          * Futz, split the data into a new segment.
778                          */
779                         if (seg >= nsegments)
780                                 goto fail;
781                         sg[1].ds_len = sg[0].ds_len - tmpsize;
782                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
783                         sg[0].ds_len = tmpsize;
784                         sg++;
785                         seg++;
786                 }
787
788                 /*
789                  * Adjust for loop
790                  */
791                 buflen -= size;
792                 vaddr += size;
793         } while (buflen > 0);
794 fail:
795         if (buflen != 0)
796                 error = EFBIG;
797
798         *segp = seg;
799         *lastpaddrp = nextpaddr;
800
801 free_bounce:
802         if (error && (dmat->flags & BUS_DMA_COULD_BOUNCE) &&
803             map != &nobounce_dmamap) {
804                 _bus_dmamap_unload(dmat, map);
805                 return_bounce_pages(dmat, map);
806         }
807         return error;
808 }
809
810 /*
811  * Map the buffer buf into bus space using the dmamap map.
812  */
813 int
814 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
815                 bus_size_t buflen, bus_dmamap_callback_t *callback,
816                 void *callback_arg, int flags)
817 {
818         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
819         bus_dma_segment_t *segments;
820         vm_paddr_t lastaddr = 0;
821         int error, nsegs = 1;
822
823         if (map != NULL) {
824                 /*
825                  * XXX
826                  * Follow old semantics.  Once all of the callers are fixed,
827                  * we should get rid of these internal flag "adjustment".
828                  */
829                 flags &= ~BUS_DMA_NOWAIT;
830                 flags |= BUS_DMA_WAITOK;
831
832                 map->callback = callback;
833                 map->callback_arg = callback_arg;
834         }
835
836         segments = bus_dma_tag_lock(dmat, cache_segments);
837         error = _bus_dmamap_load_buffer(dmat, map, buf, buflen,
838                         segments, dmat->nsegments,
839                         NULL, flags, &lastaddr, &nsegs, 1);
840         if (error == EINPROGRESS) {
841                 KKASSERT((dmat->flags &
842                           (BUS_DMA_PRIVBZONE | BUS_DMA_ALLOCALL)) !=
843                          (BUS_DMA_PRIVBZONE | BUS_DMA_ALLOCALL));
844
845                 if (dmat->flags & BUS_DMA_PROTECTED)
846                         panic("protected dmamap callback will be defered\n");
847
848                 bus_dma_tag_unlock(dmat);
849                 return error;
850         }
851         callback(callback_arg, segments, nsegs, error);
852         bus_dma_tag_unlock(dmat);
853         return 0;
854 }
855
856 /*
857  * Like _bus_dmamap_load(), but for mbufs.
858  */
859 int
860 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
861                      struct mbuf *m0,
862                      bus_dmamap_callback2_t *callback, void *callback_arg,
863                      int flags)
864 {
865         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
866         bus_dma_segment_t *segments;
867         int nsegs, error;
868
869         /*
870          * XXX
871          * Follow old semantics.  Once all of the callers are fixed,
872          * we should get rid of these internal flag "adjustment".
873          */
874         flags &= ~BUS_DMA_WAITOK;
875         flags |= BUS_DMA_NOWAIT;
876
877         segments = bus_dma_tag_lock(dmat, cache_segments);
878         error = bus_dmamap_load_mbuf_segment(dmat, map, m0,
879                         segments, dmat->nsegments, &nsegs, flags);
880         if (error) {
881                 /* force "no valid mappings" in callback */
882                 callback(callback_arg, segments, 0,
883                          0, error);
884         } else {
885                 callback(callback_arg, segments, nsegs,
886                          m0->m_pkthdr.len, error);
887         }
888         bus_dma_tag_unlock(dmat);
889         return error;
890 }
891
892 int
893 bus_dmamap_load_mbuf_segment(bus_dma_tag_t dmat, bus_dmamap_t map,
894                              struct mbuf *m0,
895                              bus_dma_segment_t *segs, int maxsegs,
896                              int *nsegs, int flags)
897 {
898         int error;
899
900         M_ASSERTPKTHDR(m0);
901
902         KASSERT(maxsegs >= 1, ("invalid maxsegs %d\n", maxsegs));
903         KASSERT(maxsegs <= dmat->nsegments,
904                 ("%d too many segments, dmat only support %d segments\n",
905                  maxsegs, dmat->nsegments));
906         KASSERT(flags & BUS_DMA_NOWAIT,
907                 ("only BUS_DMA_NOWAIT is supported\n"));
908
909         if (m0->m_pkthdr.len <= dmat->maxsize) {
910                 int first = 1;
911                 vm_paddr_t lastaddr = 0;
912                 struct mbuf *m;
913
914                 *nsegs = 1;
915                 error = 0;
916                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
917                         if (m->m_len == 0)
918                                 continue;
919
920                         error = _bus_dmamap_load_buffer(dmat, map,
921                                         m->m_data, m->m_len,
922                                         segs, maxsegs,
923                                         NULL, flags, &lastaddr,
924                                         nsegs, first);
925                         if (error == ENOMEM && !first) {
926                                 /*
927                                  * Out of bounce pages due to too many
928                                  * fragments in the mbuf chain; return
929                                  * EFBIG instead.
930                                  */
931                                 error = EFBIG;
932                         }
933                         first = 0;
934                 }
935 #ifdef INVARIANTS
936                 if (!error)
937                         KKASSERT(*nsegs <= maxsegs && *nsegs >= 1);
938 #endif
939         } else {
940                 *nsegs = 0;
941                 error = EINVAL;
942         }
943         KKASSERT(error != EINPROGRESS);
944         return error;
945 }
946
947 /*
948  * Like _bus_dmamap_load(), but for uios.
949  */
950 int
951 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
952                     struct uio *uio,
953                     bus_dmamap_callback2_t *callback, void *callback_arg,
954                     int flags)
955 {
956         vm_paddr_t lastaddr;
957         int nsegs, error, first, i;
958         bus_size_t resid;
959         struct iovec *iov;
960         pmap_t pmap;
961         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
962         bus_dma_segment_t *segments;
963         bus_dma_segment_t *segs;
964         int nsegs_left;
965
966         if (dmat->nsegments <= BUS_DMA_CACHE_SEGMENTS)
967                 segments = cache_segments;
968         else
969                 segments = kmalloc(sizeof(bus_dma_segment_t) * dmat->nsegments,
970                                    M_DEVBUF, M_WAITOK | M_ZERO);
971
972         /*
973          * XXX
974          * Follow old semantics.  Once all of the callers are fixed,
975          * we should get rid of these internal flag "adjustment".
976          */
977         flags &= ~BUS_DMA_WAITOK;
978         flags |= BUS_DMA_NOWAIT;
979
980         resid = (bus_size_t)uio->uio_resid;
981         iov = uio->uio_iov;
982
983         segs = segments;
984         nsegs_left = dmat->nsegments;
985
986         if (uio->uio_segflg == UIO_USERSPACE) {
987                 struct thread *td;
988
989                 td = uio->uio_td;
990                 KASSERT(td != NULL && td->td_proc != NULL,
991                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
992                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
993         } else {
994                 pmap = NULL;
995         }
996
997         error = 0;
998         nsegs = 1;
999         first = 1;
1000         lastaddr = 0;
1001         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
1002                 /*
1003                  * Now at the first iovec to load.  Load each iovec
1004                  * until we have exhausted the residual count.
1005                  */
1006                 bus_size_t minlen =
1007                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
1008                 caddr_t addr = (caddr_t) iov[i].iov_base;
1009
1010                 error = _bus_dmamap_load_buffer(dmat, map, addr, minlen,
1011                                 segs, nsegs_left,
1012                                 pmap, flags, &lastaddr, &nsegs, first);
1013                 first = 0;
1014
1015                 resid -= minlen;
1016                 if (error == 0) {
1017                         nsegs_left -= nsegs;
1018                         segs += nsegs;
1019                 }
1020         }
1021
1022         /*
1023          * Minimum one DMA segment, even if 0-length buffer.
1024          */
1025         if (nsegs_left == dmat->nsegments)
1026                 --nsegs_left;
1027
1028         if (error) {
1029                 /* force "no valid mappings" in callback */
1030                 callback(callback_arg, segments, 0,
1031                          0, error);
1032         } else {
1033                 callback(callback_arg, segments, dmat->nsegments - nsegs_left,
1034                          (bus_size_t)uio->uio_resid, error);
1035         }
1036         if (dmat->nsegments > BUS_DMA_CACHE_SEGMENTS)
1037                 kfree(segments, M_DEVBUF);
1038         return error;
1039 }
1040
1041 /*
1042  * Release the mapping held by map.
1043  */
1044 void
1045 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
1046 {
1047         struct bounce_page *bpage;
1048
1049         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1050                 STAILQ_REMOVE_HEAD(&map->bpages, links);
1051                 free_bounce_page(dmat, bpage);
1052         }
1053 }
1054
1055 void
1056 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
1057 {
1058         struct bounce_page *bpage;
1059
1060         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1061                 /*
1062                  * Handle data bouncing.  We might also
1063                  * want to add support for invalidating
1064                  * the caches on broken hardware
1065                  */
1066                 switch (op) {
1067                 case BUS_DMASYNC_PREWRITE:
1068                         while (bpage != NULL) {
1069                                 bcopy((void *)bpage->datavaddr,
1070                                       (void *)bpage->vaddr,
1071                                       bpage->datacount);
1072                                 bpage = STAILQ_NEXT(bpage, links);
1073                         }
1074                         dmat->bounce_zone->total_bounced++;
1075                         break;
1076
1077                 case BUS_DMASYNC_POSTREAD:
1078                         while (bpage != NULL) {
1079                                 bcopy((void *)bpage->vaddr,
1080                                       (void *)bpage->datavaddr,
1081                                       bpage->datacount);
1082                                 bpage = STAILQ_NEXT(bpage, links);
1083                         }
1084                         dmat->bounce_zone->total_bounced++;
1085                         break;
1086
1087                 case BUS_DMASYNC_PREREAD:
1088                 case BUS_DMASYNC_POSTWRITE:
1089                         /* No-ops */
1090                         break;
1091                 }
1092         }
1093 }
1094
1095 static int
1096 alloc_bounce_zone(bus_dma_tag_t dmat)
1097 {
1098         struct bounce_zone *bz, *new_bz;
1099
1100         KASSERT(dmat->bounce_zone == NULL,
1101                 ("bounce zone was already assigned\n"));
1102
1103         new_bz = kmalloc(sizeof(*new_bz), M_DEVBUF, M_INTWAIT | M_ZERO);
1104
1105         lwkt_gettoken(&bounce_zone_tok);
1106
1107         if ((dmat->flags & BUS_DMA_PRIVBZONE) == 0) {
1108                 /*
1109                  * For shared bounce zone, check to see
1110                  * if we already have a suitable zone
1111                  */
1112                 STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1113                         if (dmat->alignment <= bz->alignment &&
1114                             dmat->lowaddr >= bz->lowaddr) {
1115                                 lwkt_reltoken(&bounce_zone_tok);
1116
1117                                 dmat->bounce_zone = bz;
1118                                 kfree(new_bz, M_DEVBUF);
1119                                 return 0;
1120                         }
1121                 }
1122         }
1123         bz = new_bz;
1124
1125 #ifdef SMP
1126         spin_init(&bz->spin);
1127 #endif
1128         STAILQ_INIT(&bz->bounce_page_list);
1129         STAILQ_INIT(&bz->bounce_map_waitinglist);
1130         bz->free_bpages = 0;
1131         bz->reserved_bpages = 0;
1132         bz->active_bpages = 0;
1133         bz->lowaddr = dmat->lowaddr;
1134         bz->alignment = round_page(dmat->alignment);
1135         ksnprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1136
1137         if ((dmat->flags & BUS_DMA_PRIVBZONE) == 0) {
1138                 ksnprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1139                 busdma_zonecount++;
1140                 STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1141         } else {
1142                 ksnprintf(bz->zoneid, 8, "zone%d", busdma_priv_zonecount);
1143                 busdma_priv_zonecount--;
1144         }
1145
1146         lwkt_reltoken(&bounce_zone_tok);
1147
1148         dmat->bounce_zone = bz;
1149
1150         sysctl_ctx_init(&bz->sysctl_ctx);
1151         bz->sysctl_tree = SYSCTL_ADD_NODE(&bz->sysctl_ctx,
1152             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1153             CTLFLAG_RD, 0, "");
1154         if (bz->sysctl_tree == NULL) {
1155                 sysctl_ctx_free(&bz->sysctl_ctx);
1156                 return 0;       /* XXX error code? */
1157         }
1158
1159         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1160             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1161             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1162             "Total bounce pages");
1163         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1164             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1165             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1166             "Free bounce pages");
1167         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1168             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1169             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1170             "Reserved bounce pages");
1171         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1172             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1173             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1174             "Active bounce pages");
1175         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1176             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1177             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1178             "Total bounce requests");
1179         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1180             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1181             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1182             "Total bounce requests that were deferred");
1183         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1184             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1185             "reserve_failed", CTLFLAG_RD, &bz->reserve_failed, 0,
1186             "Total bounce page reservations that were failed");
1187         SYSCTL_ADD_STRING(&bz->sysctl_ctx,
1188             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1189             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1190         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1191             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1192             "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
1193
1194         return 0;
1195 }
1196
1197 static int
1198 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages, int flags)
1199 {
1200         struct bounce_zone *bz = dmat->bounce_zone;
1201         int count = 0, mflags;
1202
1203         if (flags & BUS_DMA_NOWAIT)
1204                 mflags = M_NOWAIT;
1205         else
1206                 mflags = M_WAITOK;
1207
1208         while (numpages > 0) {
1209                 struct bounce_page *bpage;
1210
1211                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
1212
1213                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1214                                                          mflags, 0ul,
1215                                                          bz->lowaddr,
1216                                                          bz->alignment, 0);
1217                 if (bpage->vaddr == 0) {
1218                         kfree(bpage, M_DEVBUF);
1219                         break;
1220                 }
1221                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1222
1223                 BZ_LOCK(bz);
1224                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1225                 total_bounce_pages++;
1226                 bz->total_bpages++;
1227                 bz->free_bpages++;
1228                 BZ_UNLOCK(bz);
1229
1230                 count++;
1231                 numpages--;
1232         }
1233         return count;
1234 }
1235
1236 static void
1237 free_bounce_pages_all(bus_dma_tag_t dmat)
1238 {
1239         struct bounce_zone *bz = dmat->bounce_zone;
1240         struct bounce_page *bpage;
1241
1242         BZ_LOCK(bz);
1243
1244         while ((bpage = STAILQ_FIRST(&bz->bounce_page_list)) != NULL) {
1245                 STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1246
1247                 KKASSERT(total_bounce_pages > 0);
1248                 total_bounce_pages--;
1249
1250                 KKASSERT(bz->total_bpages > 0);
1251                 bz->total_bpages--;
1252
1253                 KKASSERT(bz->free_bpages > 0);
1254                 bz->free_bpages--;
1255
1256                 contigfree((void *)bpage->vaddr, PAGE_SIZE, M_DEVBUF);
1257                 kfree(bpage, M_DEVBUF);
1258         }
1259         if (bz->total_bpages) {
1260                 kprintf("#%d bounce pages are still in use\n",
1261                         bz->total_bpages);
1262                 print_backtrace(-1);
1263         }
1264
1265         BZ_UNLOCK(bz);
1266 }
1267
1268 static void
1269 free_bounce_zone(bus_dma_tag_t dmat)
1270 {
1271         struct bounce_zone *bz = dmat->bounce_zone;
1272
1273         if (bz == NULL)
1274                 return;
1275
1276         if ((dmat->flags & BUS_DMA_PRIVBZONE) == 0)
1277                 return;
1278
1279         free_bounce_pages_all(dmat);
1280         dmat->bounce_zone = NULL;
1281
1282         sysctl_ctx_free(&bz->sysctl_ctx);
1283         kfree(bz, M_DEVBUF);
1284 }
1285
1286 /* Assume caller holds bounce zone spinlock */
1287 static int
1288 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1289 {
1290         struct bounce_zone *bz = dmat->bounce_zone;
1291         int pages;
1292
1293         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1294         if (!commit && map->pagesneeded > (map->pagesreserved + pages)) {
1295                 bz->reserve_failed++;
1296                 return (map->pagesneeded - (map->pagesreserved + pages));
1297         }
1298
1299         bz->free_bpages -= pages;
1300
1301         bz->reserved_bpages += pages;
1302         KKASSERT(bz->reserved_bpages <= bz->total_bpages);
1303
1304         map->pagesreserved += pages;
1305         pages = map->pagesneeded - map->pagesreserved;
1306
1307         return pages;
1308 }
1309
1310 static void
1311 return_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
1312 {
1313         struct bounce_zone *bz = dmat->bounce_zone;
1314         int reserved = map->pagesreserved;
1315         bus_dmamap_t wait_map;
1316
1317         map->pagesreserved = 0;
1318         map->pagesneeded = 0;
1319
1320         if (reserved == 0)
1321                 return;
1322
1323         BZ_LOCK(bz);
1324
1325         bz->free_bpages += reserved;
1326         KKASSERT(bz->free_bpages <= bz->total_bpages);
1327
1328         KKASSERT(bz->reserved_bpages >= reserved);
1329         bz->reserved_bpages -= reserved;
1330
1331         wait_map = get_map_waiting(dmat);
1332
1333         BZ_UNLOCK(bz);
1334
1335         if (wait_map != NULL)
1336                 add_map_callback(map);
1337 }
1338
1339 static bus_addr_t
1340 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1341                 bus_size_t size)
1342 {
1343         struct bounce_zone *bz = dmat->bounce_zone;
1344         struct bounce_page *bpage;
1345
1346         KASSERT(map->pagesneeded > 0, ("map doesn't need any pages"));
1347         map->pagesneeded--;
1348
1349         KASSERT(map->pagesreserved > 0, ("map doesn't reserve any pages"));
1350         map->pagesreserved--;
1351
1352         BZ_LOCK(bz);
1353
1354         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1355         KASSERT(bpage != NULL, ("free page list is empty"));
1356         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1357
1358         KKASSERT(bz->reserved_bpages > 0);
1359         bz->reserved_bpages--;
1360
1361         bz->active_bpages++;
1362         KKASSERT(bz->active_bpages <= bz->total_bpages);
1363
1364         BZ_UNLOCK(bz);
1365
1366         bpage->datavaddr = vaddr;
1367         bpage->datacount = size;
1368         STAILQ_INSERT_TAIL(&map->bpages, bpage, links);
1369         return bpage->busaddr;
1370 }
1371
1372 static void
1373 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1374 {
1375         struct bounce_zone *bz = dmat->bounce_zone;
1376         bus_dmamap_t map;
1377
1378         bpage->datavaddr = 0;
1379         bpage->datacount = 0;
1380
1381         BZ_LOCK(bz);
1382
1383         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1384
1385         bz->free_bpages++;
1386         KKASSERT(bz->free_bpages <= bz->total_bpages);
1387
1388         KKASSERT(bz->active_bpages > 0);
1389         bz->active_bpages--;
1390
1391         map = get_map_waiting(dmat);
1392
1393         BZ_UNLOCK(bz);
1394
1395         if (map != NULL)
1396                 add_map_callback(map);
1397 }
1398
1399 /* Assume caller holds bounce zone spinlock */
1400 static bus_dmamap_t
1401 get_map_waiting(bus_dma_tag_t dmat)
1402 {
1403         struct bounce_zone *bz = dmat->bounce_zone;
1404         bus_dmamap_t map;
1405
1406         map = STAILQ_FIRST(&bz->bounce_map_waitinglist);
1407         if (map != NULL) {
1408                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1409                         STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
1410                         bz->total_deferred++;
1411                 } else {
1412                         map = NULL;
1413                 }
1414         }
1415         return map;
1416 }
1417
1418 static void
1419 add_map_callback(bus_dmamap_t map)
1420 {
1421         spin_lock(&bounce_map_list_spin);
1422         STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
1423         busdma_swi_pending = 1;
1424         setsoftvm();
1425         spin_unlock(&bounce_map_list_spin);
1426 }
1427
1428 void
1429 busdma_swi(void)
1430 {
1431         bus_dmamap_t map;
1432
1433         spin_lock(&bounce_map_list_spin);
1434         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1435                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1436                 spin_unlock(&bounce_map_list_spin);
1437                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
1438                                 map->callback, map->callback_arg, /*flags*/0);
1439                 spin_lock(&bounce_map_list_spin);
1440         }
1441         spin_unlock(&bounce_map_list_spin);
1442 }