659af36ca8358a51c58db23e1251cd396f6efd45
[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 1.16.2.2 2003/01/23 00:55:27 scottl 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/thread2.h>
36 #include <sys/bus_dma.h>
37
38 #include <vm/vm.h>
39 #include <vm/vm_page.h>
40
41 /* XXX needed for to access pmap to convert per-proc virtual to physical */
42 #include <sys/proc.h>
43 #include <sys/lock.h>
44 #include <vm/vm_map.h>
45
46 #include <machine/md_var.h>
47
48 #define MAX_BPAGES 1024
49
50 struct bus_dma_tag {
51         bus_dma_tag_t     parent;
52         bus_size_t        alignment;
53         bus_size_t        boundary;
54         bus_addr_t        lowaddr;
55         bus_addr_t        highaddr;
56         bus_dma_filter_t *filter;
57         void             *filterarg;
58         bus_size_t        maxsize;
59         u_int             nsegments;
60         bus_size_t        maxsegsz;
61         int               flags;
62         int               ref_count;
63         int               map_count;
64         bus_dma_segment_t *segments;
65 };
66
67 struct bounce_page {
68         vm_offset_t     vaddr;          /* kva of bounce buffer */
69         bus_addr_t      busaddr;        /* Physical address */
70         vm_offset_t     datavaddr;      /* kva of client data */
71         bus_size_t      datacount;      /* client data count */
72         STAILQ_ENTRY(bounce_page) links;
73 };
74
75 int busdma_swi_pending;
76
77 static STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
78 static int free_bpages;
79 static int reserved_bpages;
80 static int active_bpages;
81 static int total_bpages;
82 static bus_addr_t bounce_lowaddr = BUS_SPACE_MAXADDR;
83
84 struct bus_dmamap {
85         struct bp_list         bpages;
86         int                    pagesneeded;
87         int                    pagesreserved;
88         bus_dma_tag_t          dmat;
89         void                  *buf;             /* unmapped buffer pointer */
90         bus_size_t             buflen;          /* unmapped buffer length */
91         bus_dmamap_callback_t *callback;
92         void                  *callback_arg;
93         STAILQ_ENTRY(bus_dmamap) links;
94 };
95
96 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
97 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
98 static struct bus_dmamap nobounce_dmamap;
99
100 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
101 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map);
102 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
103                                    vm_offset_t vaddr, bus_size_t size);
104 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
105 static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
106
107 static __inline int
108 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
109 {
110         int retval;
111
112         retval = 0;
113         do {
114                 if (paddr > dmat->lowaddr
115                  && paddr <= dmat->highaddr
116                  && (dmat->filter == NULL
117                   || (*dmat->filter)(dmat->filterarg, paddr) != 0))
118                         retval = 1;
119
120                 dmat = dmat->parent;            
121         } while (retval == 0 && dmat != NULL);
122         return (retval);
123 }
124
125 #define BUS_DMA_MIN_ALLOC_COMP BUS_DMA_BUS4
126 /*
127  * Allocate a device specific dma_tag.
128  */
129 int
130 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
131                    bus_size_t boundary, bus_addr_t lowaddr,
132                    bus_addr_t highaddr, bus_dma_filter_t *filter,
133                    void *filterarg, bus_size_t maxsize, int nsegments,
134                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
135 {
136         bus_dma_tag_t newtag;
137         int error = 0;
138
139         /* Return a NULL tag on failure */
140         *dmat = NULL;
141
142         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT);
143
144         newtag->parent = parent;
145         newtag->alignment = alignment;
146         newtag->boundary = boundary;
147         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
148         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
149         newtag->filter = filter;
150         newtag->filterarg = filterarg;
151         newtag->maxsize = maxsize;
152         newtag->nsegments = nsegments;
153         newtag->maxsegsz = maxsegsz;
154         newtag->flags = flags;
155         newtag->ref_count = 1; /* Count ourself */
156         newtag->map_count = 0;
157         newtag->segments = NULL;
158         
159         /* Take into account any restrictions imposed by our parent tag */
160         if (parent != NULL) {
161                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
162                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
163                 /*
164                  * XXX Not really correct??? Probably need to honor boundary
165                  *     all the way up the inheritence chain.
166                  */
167                 newtag->boundary = MAX(parent->boundary, newtag->boundary);
168                 if (newtag->filter == NULL) {
169                         /*
170                          * Short circuit looking at our parent directly
171                          * since we have encapsulated all of its information
172                          */
173                         newtag->filter = parent->filter;
174                         newtag->filterarg = parent->filterarg;
175                         newtag->parent = parent->parent;
176                 }
177                 if (newtag->parent != NULL) {
178                         parent->ref_count++;
179                 }
180         }
181         
182         if (newtag->lowaddr < ptoa(Maxmem) &&
183             (flags & BUS_DMA_ALLOCNOW) != 0) {
184                 /* Must bounce */
185
186                 if (lowaddr > bounce_lowaddr) {
187                         /*
188                          * Go through the pool and kill any pages
189                          * that don't reside below lowaddr.
190                          */
191                         panic("bus_dma_tag_create: page reallocation "
192                               "not implemented");
193                 }
194                 if (ptoa(total_bpages) < maxsize) {
195                         int pages;
196
197                         pages = atop(maxsize) - total_bpages;
198
199                         /* Add pages to our bounce pool */
200                         if (alloc_bounce_pages(newtag, pages) < pages)
201                                 error = ENOMEM;
202                 }
203                 /* Performed initial allocation */
204                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
205         }
206         
207         if (error != 0) {
208                 kfree(newtag, M_DEVBUF);
209         } else {
210                 *dmat = newtag;
211         }
212         return (error);
213 }
214
215 int
216 bus_dma_tag_destroy(bus_dma_tag_t dmat)
217 {
218         if (dmat != NULL) {
219
220                 if (dmat->map_count != 0)
221                         return (EBUSY);
222
223                 while (dmat != NULL) {
224                         bus_dma_tag_t parent;
225
226                         parent = dmat->parent;
227                         dmat->ref_count--;
228                         if (dmat->ref_count == 0) {
229                                 if (dmat->segments != NULL)
230                                         kfree(dmat->segments, M_DEVBUF);
231                                 kfree(dmat, M_DEVBUF);
232                                 /*
233                                  * Last reference count, so
234                                  * release our reference
235                                  * count on our parent.
236                                  */
237                                 dmat = parent;
238                         } else
239                                 dmat = NULL;
240                 }
241         }
242         return (0);
243 }
244
245 /*
246  * Allocate a handle for mapping from kva/uva/physical
247  * address space into bus device space.
248  */
249 int
250 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
251 {
252         int error;
253
254         error = 0;
255
256         if (dmat->segments == NULL) {
257                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
258                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) * 
259                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
260         }
261
262         if (dmat->lowaddr < ptoa(Maxmem)) {
263                 /* Must bounce */
264                 int maxpages;
265
266                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
267                 if (*mapp == NULL)
268                         return (ENOMEM);
269                 /* Initialize the new map */
270                 STAILQ_INIT(&((*mapp)->bpages));
271                 /*
272                  * Attempt to add pages to our pool on a per-instance
273                  * basis up to a sane limit.
274                  */
275                 maxpages = MIN(MAX_BPAGES, Maxmem - atop(dmat->lowaddr));
276                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
277                  || (dmat->map_count > 0
278                   && total_bpages < maxpages)) {
279                         int pages;
280
281                         if (dmat->lowaddr > bounce_lowaddr) {
282                                 /*
283                                  * Go through the pool and kill any pages
284                                  * that don't reside below lowaddr.
285                                  */
286                                 panic("bus_dmamap_create: page reallocation "
287                                       "not implemented");
288                         }
289
290                         pages = MAX(atop(dmat->maxsize), 1);
291                         pages = MIN(maxpages - total_bpages, pages);
292                         pages = MAX(pages, 1);
293                         if (alloc_bounce_pages(dmat, pages) < pages)
294                                 error = ENOMEM;
295
296                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
297                                 if (error == 0)
298                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
299                         } else {
300                                 error = 0;
301                         }
302                 }
303         } else {
304                 *mapp = NULL;
305         }
306         if (error == 0)
307                 dmat->map_count++;
308         return (error);
309 }
310
311 /*
312  * Destroy a handle for mapping from kva/uva/physical
313  * address space into bus device space.
314  */
315 int
316 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
317 {
318         if (map != NULL) {
319                 if (STAILQ_FIRST(&map->bpages) != NULL)
320                         return (EBUSY);
321                 kfree(map, M_DEVBUF);
322         }
323         dmat->map_count--;
324         return (0);
325 }
326
327
328 /*
329  * Allocate a piece of memory that can be efficiently mapped into
330  * bus device space based on the constraints lited in the dma tag.
331  *
332  * mapp is degenerate.  By definition this allocation should not require
333  * bounce buffers so do not allocate a dma map.
334  */
335 int
336 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
337                  bus_dmamap_t *mapp)
338 {
339         int mflags;
340         /* If we succeed, no mapping/bouncing will be required */
341         *mapp = NULL;
342
343         if (dmat->segments == NULL) {
344                 KKASSERT(dmat->nsegments < 16384);
345                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) * 
346                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
347         }
348
349         if (flags & BUS_DMA_NOWAIT)
350                 mflags = M_NOWAIT;
351         else
352                 mflags = M_WAITOK;
353         if (flags & BUS_DMA_ZERO)
354                 mflags |= M_ZERO;
355
356         if ((dmat->maxsize <= PAGE_SIZE) &&
357             dmat->lowaddr >= ptoa(Maxmem)) {
358                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
359                 /*
360                  * XXX Check whether the allocation crossed a page boundary
361                  * and retry with power-of-2 alignment in that case.
362                  */
363                 if ((((intptr_t)*vaddr) & PAGE_MASK) !=
364                     (((intptr_t)*vaddr + dmat->maxsize) & PAGE_MASK)) {
365                         size_t size;
366                         kfree(*vaddr, M_DEVBUF);
367                         /* XXX check for overflow? */
368                         for (size = 1; size <= dmat->maxsize; size <<= 1)
369                                 ;
370                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
371                 }
372         } else {
373                 /*
374                  * XXX Use Contigmalloc until it is merged into this facility
375                  *     and handles multi-seg allocations.  Nobody is doing
376                  *     multi-seg allocations yet though.
377                  */
378                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
379                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
380                     dmat->boundary);
381         }
382         if (*vaddr == NULL)
383                 return (ENOMEM);
384         return (0);
385 }
386
387 /*
388  * Free a piece of memory and it's allociated dmamap, that was allocated
389  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
390  */
391 void
392 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
393 {
394         /*
395          * dmamem does not need to be bounced, so the map should be
396          * NULL
397          */
398         if (map != NULL)
399                 panic("bus_dmamem_free: Invalid map freed\n");
400         if ((dmat->maxsize <= PAGE_SIZE) &&
401             dmat->lowaddr >= ptoa(Maxmem))
402                 kfree(vaddr, M_DEVBUF);
403         else
404                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
405 }
406
407 #define BUS_DMAMAP_NSEGS ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
408
409 /*
410  * Map the buffer buf into bus space using the dmamap map.
411  */
412 int
413 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
414                 bus_size_t buflen, bus_dmamap_callback_t *callback,
415                 void *callback_arg, int flags)
416 {
417         vm_offset_t             vaddr;
418         vm_paddr_t              paddr;
419         bus_dma_segment_t      *sg;
420         int                     seg;
421         int                     error;
422         vm_paddr_t              nextpaddr;
423         bus_addr_t              bmask;
424
425         if (map == NULL)
426                 map = &nobounce_dmamap;
427
428         error = 0;
429         /*
430          * If we are being called during a callback, pagesneeded will
431          * be non-zero, so we can avoid doing the work twice.
432          */
433         if (dmat->lowaddr < ptoa(Maxmem) &&
434             map->pagesneeded == 0) {
435                 vm_offset_t     vendaddr;
436
437                 /*
438                  * Count the number of bounce pages
439                  * needed in order to complete this transfer
440                  */
441                 vaddr = trunc_page((vm_offset_t)buf);
442                 vendaddr = (vm_offset_t)buf + buflen;
443
444                 while (vaddr < vendaddr) {
445                         paddr = pmap_kextract(vaddr);
446                         if (run_filter(dmat, paddr) != 0) {
447
448                                 map->pagesneeded++;
449                         }
450                         vaddr += PAGE_SIZE;
451                 }
452         }
453
454         /* Reserve Necessary Bounce Pages */
455         if (map->pagesneeded != 0) {
456                 crit_enter();
457                 if (reserve_bounce_pages(dmat, map) != 0) {
458
459                         /* Queue us for resources */
460                         map->dmat = dmat;
461                         map->buf = buf;
462                         map->buflen = buflen;
463                         map->callback = callback;
464                         map->callback_arg = callback_arg;
465
466                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
467                         crit_exit();
468
469                         return (EINPROGRESS);
470                 }
471                 crit_exit();
472         }
473
474         vaddr = (vm_offset_t)buf;
475         sg = dmat->segments;
476         seg = 1;
477         sg->ds_len = 0;
478         nextpaddr = 0;
479         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
480
481         /* force at least one segment */
482         do {
483                 bus_size_t      size;
484
485                 /*
486                  * Per-page main loop
487                  */
488                 paddr = pmap_kextract(vaddr);
489                 size = PAGE_SIZE - (paddr & PAGE_MASK);
490                 if (size > buflen)
491                         size = buflen;
492                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
493                         /* 
494                          * note: this paddr has the same in-page offset
495                          * as vaddr and thus the paddr above, so the
496                          * size does not have to be recalculated
497                          */
498                         paddr = add_bounce_page(dmat, map, vaddr, size);
499                 }
500
501                 /*
502                  * Fill in the bus_dma_segment
503                  */
504                 if (sg->ds_len == 0) {
505                         sg->ds_addr = paddr;
506                         sg->ds_len = size;
507                 } else if (paddr == nextpaddr) {
508                         sg->ds_len += size;
509                 } else {
510                         sg++;
511                         seg++;
512                         if (seg > dmat->nsegments)
513                                 break;
514                         sg->ds_addr = paddr;
515                         sg->ds_len = size;
516                 }
517                 nextpaddr = paddr + size;
518
519                 /*
520                  * Handle maxsegsz and boundary issues with a nested loop
521                  */
522                 for (;;) {
523                         bus_size_t      tmpsize;
524
525                         /*
526                          * Limit to the boundary and maximum segment size
527                          */
528                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
529                                 tmpsize = dmat->boundary -
530                                           (sg->ds_addr & ~bmask);
531                                 if (tmpsize > dmat->maxsegsz)
532                                         tmpsize = dmat->maxsegsz;
533                                 KKASSERT(tmpsize < sg->ds_len);
534                         } else if (sg->ds_len > dmat->maxsegsz) {
535                                 tmpsize = dmat->maxsegsz;
536                         } else {
537                                 break;
538                         }
539
540                         /*
541                          * Futz, split the data into a new segment.
542                          */
543                         if (seg >= dmat->nsegments)
544                                 goto fail;
545                         sg[1].ds_len = sg[0].ds_len - tmpsize;
546                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
547                         sg[0].ds_len = tmpsize;
548                         sg++;
549                         seg++;
550                 }
551
552                 /*
553                  * Adjust for loop
554                  */
555                 buflen -= size;
556                 vaddr += size;
557         } while (buflen > 0);
558
559 fail:
560         if (buflen != 0) {
561                 kprintf("bus_dmamap_load: Too many segs! buf_len = 0x%lx\n",
562                        (u_long)buflen);
563                 error = EFBIG;
564         }
565
566         (*callback)(callback_arg, dmat->segments, seg, error);
567
568         return (0);
569 }
570
571 /*
572  * Utility function to load a linear buffer.  lastaddrp holds state
573  * between invocations (for multiple-buffer loads).  segp contains
574  * the starting segment on entrace, and the ending segment on exit.
575  * first indicates if this is the first invocation of this function.
576  */
577 static int
578 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
579                         void *buf, bus_size_t buflen,
580                         struct thread *td,
581                         int flags,
582                         vm_offset_t *lastaddrp,
583                         int *segp,
584                         int first)
585 {
586         bus_dma_segment_t *segs;
587         bus_size_t sgsize;
588         bus_addr_t curaddr, lastaddr, baddr, bmask;
589         vm_offset_t vaddr = (vm_offset_t)buf;
590         int seg;
591         pmap_t pmap;
592
593         if (td->td_proc != NULL)
594                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
595         else
596                 pmap = NULL;
597
598         segs = dmat->segments;
599         lastaddr = *lastaddrp;
600         bmask  = ~(dmat->boundary - 1);
601
602         for (seg = *segp; buflen > 0 ; ) {
603                 /*
604                  * Get the physical address for this segment.
605                  */
606                 if (pmap)
607                         curaddr = pmap_extract(pmap, vaddr);
608                 else
609                         curaddr = pmap_kextract(vaddr);
610
611                 /*
612                  * Compute the segment size, and adjust counts.
613                  */
614                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
615                 if (buflen < sgsize)
616                         sgsize = buflen;
617
618                 /*
619                  * Make sure we don't cross any boundaries.
620                  */
621                 if (dmat->boundary > 0) {
622                         baddr = (curaddr + dmat->boundary) & bmask;
623                         if (sgsize > (baddr - curaddr))
624                                 sgsize = (baddr - curaddr);
625                 }
626
627                 /*
628                  * Insert chunk into a segment, coalescing with
629                  * previous segment if possible.
630                  */
631                 if (first) {
632                         segs[seg].ds_addr = curaddr;
633                         segs[seg].ds_len = sgsize;
634                         first = 0;
635                 } else {
636                         if (curaddr == lastaddr &&
637                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
638                             (dmat->boundary == 0 ||
639                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
640                                 segs[seg].ds_len += sgsize;
641                         else {
642                                 if (++seg >= dmat->nsegments)
643                                         break;
644                                 segs[seg].ds_addr = curaddr;
645                                 segs[seg].ds_len = sgsize;
646                         }
647                 }
648
649                 lastaddr = curaddr + sgsize;
650                 vaddr += sgsize;
651                 buflen -= sgsize;
652         }
653
654         *segp = seg;
655         *lastaddrp = lastaddr;
656
657         /*
658          * Did we fit?
659          */
660         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
661 }
662
663 /*
664  * Like _bus_dmamap_load(), but for mbufs.
665  */
666 int
667 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
668                      struct mbuf *m0,
669                      bus_dmamap_callback2_t *callback, void *callback_arg,
670                      int flags)
671 {
672         int nsegs, error;
673
674         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
675                 ("bus_dmamap_load_mbuf: No support for bounce pages!"));
676         KASSERT(m0->m_flags & M_PKTHDR,
677                 ("bus_dmamap_load_mbuf: no packet header"));
678
679         nsegs = 0;
680         error = 0;
681         if (m0->m_pkthdr.len <= dmat->maxsize) {
682                 int first = 1;
683                 vm_offset_t lastaddr = 0;
684                 struct mbuf *m;
685
686                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
687                         if ( m->m_len == 0 )
688                                 continue;
689                         error = _bus_dmamap_load_buffer(dmat,
690                                         m->m_data, m->m_len,
691                                         curthread, flags, &lastaddr,
692                                         &nsegs, first);
693                         first = 0;
694                 }
695         } else {
696                 error = EINVAL;
697         }
698
699         if (error) {
700                 /* force "no valid mappings" in callback */
701                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
702         } else {
703                 (*callback)(callback_arg, dmat->segments,
704                             nsegs+1, m0->m_pkthdr.len, error);
705         }
706         return (error);
707 }
708
709 /*
710  * Like _bus_dmamap_load(), but for uios.
711  */
712 int
713 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
714                     struct uio *uio,
715                     bus_dmamap_callback2_t *callback, void *callback_arg,
716                     int flags)
717 {
718         vm_offset_t lastaddr;
719         int nsegs, error, first, i;
720         bus_size_t resid;
721         struct iovec *iov;
722         struct thread *td = NULL;
723
724         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
725                 ("bus_dmamap_load_uio: No support for bounce pages!"));
726
727         resid = uio->uio_resid;
728         iov = uio->uio_iov;
729
730         if (uio->uio_segflg == UIO_USERSPACE) {
731                 td = uio->uio_td;
732                 KASSERT(td != NULL && td->td_proc != NULL,
733                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
734         }
735
736         nsegs = 0;
737         error = 0;
738         first = 1;
739         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
740                 /*
741                  * Now at the first iovec to load.  Load each iovec
742                  * until we have exhausted the residual count.
743                  */
744                 bus_size_t minlen =
745                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
746                 caddr_t addr = (caddr_t) iov[i].iov_base;
747
748                 error = _bus_dmamap_load_buffer(dmat,
749                                 addr, minlen,
750                                 td, flags, &lastaddr, &nsegs, first);
751                 first = 0;
752
753                 resid -= minlen;
754         }
755
756         if (error) {
757                 /* force "no valid mappings" in callback */
758                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
759         } else {
760                 (*callback)(callback_arg, dmat->segments,
761                             nsegs+1, uio->uio_resid, error);
762         }
763         return (error);
764 }
765
766 /*
767  * Release the mapping held by map.
768  */
769 void
770 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
771 {
772         struct bounce_page *bpage;
773
774         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
775                 STAILQ_REMOVE_HEAD(&map->bpages, links);
776                 free_bounce_page(dmat, bpage);
777         }
778 }
779
780 void
781 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
782 {
783         struct bounce_page *bpage;
784
785         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
786                 
787                 /*
788                  * Handle data bouncing.  We might also
789                  * want to add support for invalidating
790                  * the caches on broken hardware
791                  */
792                 switch (op) {
793                 case BUS_DMASYNC_PREWRITE:
794                         while (bpage != NULL) {
795                                 bcopy((void *)bpage->datavaddr,
796                                       (void *)bpage->vaddr,
797                                       bpage->datacount);
798                                 bpage = STAILQ_NEXT(bpage, links);
799                         }
800                         break;
801
802                 case BUS_DMASYNC_POSTREAD:
803                         while (bpage != NULL) {
804                                 bcopy((void *)bpage->vaddr,
805                                       (void *)bpage->datavaddr,
806                                       bpage->datacount);
807                                 bpage = STAILQ_NEXT(bpage, links);
808                         }
809                         break;
810                 case BUS_DMASYNC_PREREAD:
811                 case BUS_DMASYNC_POSTWRITE:
812                         /* No-ops */
813                         break;
814                 }
815         }
816 }
817
818 static int
819 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
820 {
821         int count;
822
823         count = 0;
824         if (total_bpages == 0) {
825                 STAILQ_INIT(&bounce_page_list);
826                 STAILQ_INIT(&bounce_map_waitinglist);
827                 STAILQ_INIT(&bounce_map_callbacklist);
828         }
829         
830         while (numpages > 0) {
831                 struct bounce_page *bpage;
832
833                 bpage = (struct bounce_page *)kmalloc(sizeof(*bpage), M_DEVBUF,
834                                                      M_INTWAIT | M_ZERO);
835
836                 if (bpage == NULL)
837                         break;
838                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
839                                                          M_NOWAIT, 0ul,
840                                                          dmat->lowaddr,
841                                                          PAGE_SIZE,
842                                                          0);
843                 if (bpage->vaddr == 0) {
844                         kfree(bpage, M_DEVBUF);
845                         break;
846                 }
847                 bpage->busaddr = pmap_kextract(bpage->vaddr);
848                 crit_enter();
849                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
850                 total_bpages++;
851                 free_bpages++;
852                 crit_exit();
853                 count++;
854                 numpages--;
855         }
856         return (count);
857 }
858
859 static int
860 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
861 {
862         int pages;
863
864         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
865         free_bpages -= pages;
866         reserved_bpages += pages;
867         map->pagesreserved += pages;
868         pages = map->pagesneeded - map->pagesreserved;
869
870         return (pages);
871 }
872
873 static bus_addr_t
874 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
875                 bus_size_t size)
876 {
877         struct bounce_page *bpage;
878
879         if (map->pagesneeded == 0)
880                 panic("add_bounce_page: map doesn't need any pages");
881         map->pagesneeded--;
882
883         if (map->pagesreserved == 0)
884                 panic("add_bounce_page: map doesn't need any pages");
885         map->pagesreserved--;
886
887         crit_enter();
888         bpage = STAILQ_FIRST(&bounce_page_list);
889         if (bpage == NULL)
890                 panic("add_bounce_page: free page list is empty");
891
892         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
893         reserved_bpages--;
894         active_bpages++;
895         crit_exit();
896
897         bpage->datavaddr = vaddr;
898         bpage->datacount = size;
899         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
900         return (bpage->busaddr);
901 }
902
903 static void
904 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
905 {
906         struct bus_dmamap *map;
907
908         bpage->datavaddr = 0;
909         bpage->datacount = 0;
910
911         crit_enter();
912         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
913         free_bpages++;
914         active_bpages--;
915         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
916                 if (reserve_bounce_pages(map->dmat, map) == 0) {
917                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
918                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
919                                            map, links);
920                         busdma_swi_pending = 1;
921                         setsoftvm();
922                 }
923         }
924         crit_exit();
925 }
926
927 void
928 busdma_swi(void)
929 {
930         struct bus_dmamap *map;
931
932         crit_enter();
933         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
934                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
935                 crit_exit();
936                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
937                                 map->callback, map->callback_arg, /*flags*/0);
938                 crit_enter();
939         }
940         crit_exit();
941 }