- Add hw.busdma sysctl tree.
[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 #include <sys/kernel.h>
38 #include <sys/sysctl.h>
39
40 #include <vm/vm.h>
41 #include <vm/vm_page.h>
42
43 /* XXX needed for to access pmap to convert per-proc virtual to physical */
44 #include <sys/proc.h>
45 #include <sys/lock.h>
46 #include <vm/vm_map.h>
47
48 #include <machine/md_var.h>
49
50 #define MAX_BPAGES 1024
51
52 struct bus_dma_tag {
53         bus_dma_tag_t     parent;
54         bus_size_t        alignment;
55         bus_size_t        boundary;
56         bus_addr_t        lowaddr;
57         bus_addr_t        highaddr;
58         bus_dma_filter_t *filter;
59         void             *filterarg;
60         bus_size_t        maxsize;
61         u_int             nsegments;
62         bus_size_t        maxsegsz;
63         int               flags;
64         int               ref_count;
65         int               map_count;
66         bus_dma_segment_t *segments;
67 };
68
69 struct bounce_page {
70         vm_offset_t     vaddr;          /* kva of bounce buffer */
71         bus_addr_t      busaddr;        /* Physical address */
72         vm_offset_t     datavaddr;      /* kva of client data */
73         bus_size_t      datacount;      /* client data count */
74         STAILQ_ENTRY(bounce_page) links;
75 };
76
77 int busdma_swi_pending;
78
79 static STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
80 static int free_bpages;
81 static int reserved_bpages;
82 static int active_bpages;
83 static int total_bpages;
84 static bus_addr_t bounce_lowaddr = BUS_SPACE_MAXADDR;
85
86 struct bus_dmamap {
87         struct bp_list         bpages;
88         int                    pagesneeded;
89         int                    pagesreserved;
90         bus_dma_tag_t          dmat;
91         void                  *buf;             /* unmapped buffer pointer */
92         bus_size_t             buflen;          /* unmapped buffer length */
93         bus_dmamap_callback_t *callback;
94         void                  *callback_arg;
95         STAILQ_ENTRY(bus_dmamap) links;
96 };
97
98 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
99 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
100 static struct bus_dmamap nobounce_dmamap;
101
102 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
103 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map);
104 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
105                                    vm_offset_t vaddr, bus_size_t size);
106 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
107 static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
108
109 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
110 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
111            "Total bounce pages");
112
113 static __inline int
114 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
115 {
116         int retval;
117
118         retval = 0;
119         do {
120                 if (paddr > dmat->lowaddr
121                  && paddr <= dmat->highaddr
122                  && (dmat->filter == NULL
123                   || (*dmat->filter)(dmat->filterarg, paddr) != 0))
124                         retval = 1;
125
126                 dmat = dmat->parent;            
127         } while (retval == 0 && dmat != NULL);
128         return (retval);
129 }
130
131 #define BUS_DMA_MIN_ALLOC_COMP BUS_DMA_BUS4
132 /*
133  * Allocate a device specific dma_tag.
134  */
135 int
136 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
137                    bus_size_t boundary, bus_addr_t lowaddr,
138                    bus_addr_t highaddr, bus_dma_filter_t *filter,
139                    void *filterarg, bus_size_t maxsize, int nsegments,
140                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
141 {
142         bus_dma_tag_t newtag;
143         int error = 0;
144
145         /* Return a NULL tag on failure */
146         *dmat = NULL;
147
148         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT);
149
150         newtag->parent = parent;
151         newtag->alignment = alignment;
152         newtag->boundary = boundary;
153         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
154         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
155         newtag->filter = filter;
156         newtag->filterarg = filterarg;
157         newtag->maxsize = maxsize;
158         newtag->nsegments = nsegments;
159         newtag->maxsegsz = maxsegsz;
160         newtag->flags = flags;
161         newtag->ref_count = 1; /* Count ourself */
162         newtag->map_count = 0;
163         newtag->segments = NULL;
164         
165         /* Take into account any restrictions imposed by our parent tag */
166         if (parent != NULL) {
167                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
168                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
169                 /*
170                  * XXX Not really correct??? Probably need to honor boundary
171                  *     all the way up the inheritence chain.
172                  */
173                 newtag->boundary = MAX(parent->boundary, newtag->boundary);
174                 if (newtag->filter == NULL) {
175                         /*
176                          * Short circuit looking at our parent directly
177                          * since we have encapsulated all of its information
178                          */
179                         newtag->filter = parent->filter;
180                         newtag->filterarg = parent->filterarg;
181                         newtag->parent = parent->parent;
182                 }
183                 if (newtag->parent != NULL) {
184                         parent->ref_count++;
185                 }
186         }
187         
188         if (newtag->lowaddr < ptoa(Maxmem) &&
189             (flags & BUS_DMA_ALLOCNOW) != 0) {
190                 /* Must bounce */
191
192                 if (lowaddr > bounce_lowaddr) {
193                         /*
194                          * Go through the pool and kill any pages
195                          * that don't reside below lowaddr.
196                          */
197                         panic("bus_dma_tag_create: page reallocation "
198                               "not implemented");
199                 }
200                 if (ptoa(total_bpages) < maxsize) {
201                         int pages;
202
203                         pages = atop(maxsize) - total_bpages;
204
205                         /* Add pages to our bounce pool */
206                         if (alloc_bounce_pages(newtag, pages) < pages)
207                                 error = ENOMEM;
208                 }
209                 /* Performed initial allocation */
210                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
211         }
212         
213         if (error != 0) {
214                 kfree(newtag, M_DEVBUF);
215         } else {
216                 *dmat = newtag;
217         }
218         return (error);
219 }
220
221 int
222 bus_dma_tag_destroy(bus_dma_tag_t dmat)
223 {
224         if (dmat != NULL) {
225
226                 if (dmat->map_count != 0)
227                         return (EBUSY);
228
229                 while (dmat != NULL) {
230                         bus_dma_tag_t parent;
231
232                         parent = dmat->parent;
233                         dmat->ref_count--;
234                         if (dmat->ref_count == 0) {
235                                 if (dmat->segments != NULL)
236                                         kfree(dmat->segments, M_DEVBUF);
237                                 kfree(dmat, M_DEVBUF);
238                                 /*
239                                  * Last reference count, so
240                                  * release our reference
241                                  * count on our parent.
242                                  */
243                                 dmat = parent;
244                         } else
245                                 dmat = NULL;
246                 }
247         }
248         return (0);
249 }
250
251 /*
252  * Allocate a handle for mapping from kva/uva/physical
253  * address space into bus device space.
254  */
255 int
256 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
257 {
258         int error;
259
260         error = 0;
261
262         if (dmat->segments == NULL) {
263                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
264                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) * 
265                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
266         }
267
268         if (dmat->lowaddr < ptoa(Maxmem)) {
269                 /* Must bounce */
270                 int maxpages;
271
272                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
273                 if (*mapp == NULL)
274                         return (ENOMEM);
275                 /* Initialize the new map */
276                 STAILQ_INIT(&((*mapp)->bpages));
277                 /*
278                  * Attempt to add pages to our pool on a per-instance
279                  * basis up to a sane limit.
280                  */
281                 maxpages = MIN(MAX_BPAGES, Maxmem - atop(dmat->lowaddr));
282                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
283                  || (dmat->map_count > 0
284                   && total_bpages < maxpages)) {
285                         int pages;
286
287                         if (dmat->lowaddr > bounce_lowaddr) {
288                                 /*
289                                  * Go through the pool and kill any pages
290                                  * that don't reside below lowaddr.
291                                  */
292                                 panic("bus_dmamap_create: page reallocation "
293                                       "not implemented");
294                         }
295
296                         pages = MAX(atop(dmat->maxsize), 1);
297                         pages = MIN(maxpages - total_bpages, pages);
298                         pages = MAX(pages, 1);
299                         if (alloc_bounce_pages(dmat, pages) < pages)
300                                 error = ENOMEM;
301
302                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
303                                 if (error == 0)
304                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
305                         } else {
306                                 error = 0;
307                         }
308                 }
309         } else {
310                 *mapp = NULL;
311         }
312         if (error == 0)
313                 dmat->map_count++;
314         return (error);
315 }
316
317 /*
318  * Destroy a handle for mapping from kva/uva/physical
319  * address space into bus device space.
320  */
321 int
322 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
323 {
324         if (map != NULL) {
325                 if (STAILQ_FIRST(&map->bpages) != NULL)
326                         return (EBUSY);
327                 kfree(map, M_DEVBUF);
328         }
329         dmat->map_count--;
330         return (0);
331 }
332
333
334 /*
335  * Allocate a piece of memory that can be efficiently mapped into
336  * bus device space based on the constraints lited in the dma tag.
337  *
338  * mapp is degenerate.  By definition this allocation should not require
339  * bounce buffers so do not allocate a dma map.
340  */
341 int
342 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
343                  bus_dmamap_t *mapp)
344 {
345         int mflags;
346         /* If we succeed, no mapping/bouncing will be required */
347         *mapp = NULL;
348
349         if (dmat->segments == NULL) {
350                 KKASSERT(dmat->nsegments < 16384);
351                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) * 
352                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
353         }
354
355         if (flags & BUS_DMA_NOWAIT)
356                 mflags = M_NOWAIT;
357         else
358                 mflags = M_WAITOK;
359         if (flags & BUS_DMA_ZERO)
360                 mflags |= M_ZERO;
361
362         if ((dmat->maxsize <= PAGE_SIZE) &&
363             dmat->lowaddr >= ptoa(Maxmem)) {
364                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
365                 /*
366                  * XXX Check whether the allocation crossed a page boundary
367                  * and retry with power-of-2 alignment in that case.
368                  */
369                 if ((((intptr_t)*vaddr) & PAGE_MASK) !=
370                     (((intptr_t)*vaddr + dmat->maxsize) & PAGE_MASK)) {
371                         size_t size;
372                         kfree(*vaddr, M_DEVBUF);
373                         /* XXX check for overflow? */
374                         for (size = 1; size <= dmat->maxsize; size <<= 1)
375                                 ;
376                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
377                 }
378         } else {
379                 /*
380                  * XXX Use Contigmalloc until it is merged into this facility
381                  *     and handles multi-seg allocations.  Nobody is doing
382                  *     multi-seg allocations yet though.
383                  */
384                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
385                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
386                     dmat->boundary);
387         }
388         if (*vaddr == NULL)
389                 return (ENOMEM);
390         return (0);
391 }
392
393 /*
394  * Free a piece of memory and it's allociated dmamap, that was allocated
395  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
396  */
397 void
398 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
399 {
400         /*
401          * dmamem does not need to be bounced, so the map should be
402          * NULL
403          */
404         if (map != NULL)
405                 panic("bus_dmamem_free: Invalid map freed\n");
406         if ((dmat->maxsize <= PAGE_SIZE) &&
407             dmat->lowaddr >= ptoa(Maxmem))
408                 kfree(vaddr, M_DEVBUF);
409         else
410                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
411 }
412
413 #define BUS_DMAMAP_NSEGS ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
414
415 /*
416  * Map the buffer buf into bus space using the dmamap map.
417  */
418 int
419 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
420                 bus_size_t buflen, bus_dmamap_callback_t *callback,
421                 void *callback_arg, int flags)
422 {
423         vm_offset_t             vaddr;
424         vm_paddr_t              paddr;
425         bus_dma_segment_t      *sg;
426         int                     seg;
427         int                     error;
428         vm_paddr_t              nextpaddr;
429         bus_addr_t              bmask;
430
431         if (map == NULL)
432                 map = &nobounce_dmamap;
433
434         error = 0;
435         /*
436          * If we are being called during a callback, pagesneeded will
437          * be non-zero, so we can avoid doing the work twice.
438          */
439         if (dmat->lowaddr < ptoa(Maxmem) &&
440             map->pagesneeded == 0) {
441                 vm_offset_t     vendaddr;
442
443                 /*
444                  * Count the number of bounce pages
445                  * needed in order to complete this transfer
446                  */
447                 vaddr = trunc_page((vm_offset_t)buf);
448                 vendaddr = (vm_offset_t)buf + buflen;
449
450                 while (vaddr < vendaddr) {
451                         paddr = pmap_kextract(vaddr);
452                         if (run_filter(dmat, paddr) != 0) {
453
454                                 map->pagesneeded++;
455                         }
456                         vaddr += PAGE_SIZE;
457                 }
458         }
459
460         /* Reserve Necessary Bounce Pages */
461         if (map->pagesneeded != 0) {
462                 crit_enter();
463                 if (reserve_bounce_pages(dmat, map) != 0) {
464
465                         /* Queue us for resources */
466                         map->dmat = dmat;
467                         map->buf = buf;
468                         map->buflen = buflen;
469                         map->callback = callback;
470                         map->callback_arg = callback_arg;
471
472                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
473                         crit_exit();
474
475                         return (EINPROGRESS);
476                 }
477                 crit_exit();
478         }
479
480         vaddr = (vm_offset_t)buf;
481         sg = dmat->segments;
482         seg = 1;
483         sg->ds_len = 0;
484         nextpaddr = 0;
485         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
486
487         /* force at least one segment */
488         do {
489                 bus_size_t      size;
490
491                 /*
492                  * Per-page main loop
493                  */
494                 paddr = pmap_kextract(vaddr);
495                 size = PAGE_SIZE - (paddr & PAGE_MASK);
496                 if (size > buflen)
497                         size = buflen;
498                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
499                         /* 
500                          * note: this paddr has the same in-page offset
501                          * as vaddr and thus the paddr above, so the
502                          * size does not have to be recalculated
503                          */
504                         paddr = add_bounce_page(dmat, map, vaddr, size);
505                 }
506
507                 /*
508                  * Fill in the bus_dma_segment
509                  */
510                 if (sg->ds_len == 0) {
511                         sg->ds_addr = paddr;
512                         sg->ds_len = size;
513                 } else if (paddr == nextpaddr) {
514                         sg->ds_len += size;
515                 } else {
516                         sg++;
517                         seg++;
518                         if (seg > dmat->nsegments)
519                                 break;
520                         sg->ds_addr = paddr;
521                         sg->ds_len = size;
522                 }
523                 nextpaddr = paddr + size;
524
525                 /*
526                  * Handle maxsegsz and boundary issues with a nested loop
527                  */
528                 for (;;) {
529                         bus_size_t      tmpsize;
530
531                         /*
532                          * Limit to the boundary and maximum segment size
533                          */
534                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
535                                 tmpsize = dmat->boundary -
536                                           (sg->ds_addr & ~bmask);
537                                 if (tmpsize > dmat->maxsegsz)
538                                         tmpsize = dmat->maxsegsz;
539                                 KKASSERT(tmpsize < sg->ds_len);
540                         } else if (sg->ds_len > dmat->maxsegsz) {
541                                 tmpsize = dmat->maxsegsz;
542                         } else {
543                                 break;
544                         }
545
546                         /*
547                          * Futz, split the data into a new segment.
548                          */
549                         if (seg >= dmat->nsegments)
550                                 goto fail;
551                         sg[1].ds_len = sg[0].ds_len - tmpsize;
552                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
553                         sg[0].ds_len = tmpsize;
554                         sg++;
555                         seg++;
556                 }
557
558                 /*
559                  * Adjust for loop
560                  */
561                 buflen -= size;
562                 vaddr += size;
563         } while (buflen > 0);
564
565 fail:
566         if (buflen != 0) {
567                 kprintf("bus_dmamap_load: Too many segs! buf_len = 0x%lx\n",
568                        (u_long)buflen);
569                 error = EFBIG;
570         }
571
572         (*callback)(callback_arg, dmat->segments, seg, error);
573
574         return (0);
575 }
576
577 /*
578  * Utility function to load a linear buffer.  lastaddrp holds state
579  * between invocations (for multiple-buffer loads).  segp contains
580  * the starting segment on entrace, and the ending segment on exit.
581  * first indicates if this is the first invocation of this function.
582  */
583 static int
584 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
585                         void *buf, bus_size_t buflen,
586                         struct thread *td,
587                         int flags,
588                         vm_offset_t *lastaddrp,
589                         int *segp,
590                         int first)
591 {
592         bus_dma_segment_t *segs;
593         bus_size_t sgsize;
594         bus_addr_t curaddr, lastaddr, baddr, bmask;
595         vm_offset_t vaddr = (vm_offset_t)buf;
596         int seg;
597         pmap_t pmap;
598
599         if (td->td_proc != NULL)
600                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
601         else
602                 pmap = NULL;
603
604         segs = dmat->segments;
605         lastaddr = *lastaddrp;
606         bmask  = ~(dmat->boundary - 1);
607
608         for (seg = *segp; buflen > 0 ; ) {
609                 /*
610                  * Get the physical address for this segment.
611                  */
612                 if (pmap)
613                         curaddr = pmap_extract(pmap, vaddr);
614                 else
615                         curaddr = pmap_kextract(vaddr);
616
617                 /*
618                  * Compute the segment size, and adjust counts.
619                  */
620                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
621                 if (buflen < sgsize)
622                         sgsize = buflen;
623
624                 /*
625                  * Make sure we don't cross any boundaries.
626                  */
627                 if (dmat->boundary > 0) {
628                         baddr = (curaddr + dmat->boundary) & bmask;
629                         if (sgsize > (baddr - curaddr))
630                                 sgsize = (baddr - curaddr);
631                 }
632
633                 /*
634                  * Insert chunk into a segment, coalescing with
635                  * previous segment if possible.
636                  */
637                 if (first) {
638                         segs[seg].ds_addr = curaddr;
639                         segs[seg].ds_len = sgsize;
640                         first = 0;
641                 } else {
642                         if (curaddr == lastaddr &&
643                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
644                             (dmat->boundary == 0 ||
645                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
646                                 segs[seg].ds_len += sgsize;
647                         else {
648                                 if (++seg >= dmat->nsegments)
649                                         break;
650                                 segs[seg].ds_addr = curaddr;
651                                 segs[seg].ds_len = sgsize;
652                         }
653                 }
654
655                 lastaddr = curaddr + sgsize;
656                 vaddr += sgsize;
657                 buflen -= sgsize;
658         }
659
660         *segp = seg;
661         *lastaddrp = lastaddr;
662
663         /*
664          * Did we fit?
665          */
666         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
667 }
668
669 /*
670  * Like _bus_dmamap_load(), but for mbufs.
671  */
672 int
673 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
674                      struct mbuf *m0,
675                      bus_dmamap_callback2_t *callback, void *callback_arg,
676                      int flags)
677 {
678         int nsegs, error;
679
680         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
681                 ("bus_dmamap_load_mbuf: No support for bounce pages!"));
682         KASSERT(m0->m_flags & M_PKTHDR,
683                 ("bus_dmamap_load_mbuf: no packet header"));
684
685         nsegs = 0;
686         error = 0;
687         if (m0->m_pkthdr.len <= dmat->maxsize) {
688                 int first = 1;
689                 vm_offset_t lastaddr = 0;
690                 struct mbuf *m;
691
692                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
693                         if ( m->m_len == 0 )
694                                 continue;
695                         error = _bus_dmamap_load_buffer(dmat,
696                                         m->m_data, m->m_len,
697                                         curthread, flags, &lastaddr,
698                                         &nsegs, first);
699                         first = 0;
700                 }
701         } else {
702                 error = EINVAL;
703         }
704
705         if (error) {
706                 /* force "no valid mappings" in callback */
707                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
708         } else {
709                 (*callback)(callback_arg, dmat->segments,
710                             nsegs+1, m0->m_pkthdr.len, error);
711         }
712         return (error);
713 }
714
715 /*
716  * Like _bus_dmamap_load(), but for uios.
717  */
718 int
719 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
720                     struct uio *uio,
721                     bus_dmamap_callback2_t *callback, void *callback_arg,
722                     int flags)
723 {
724         vm_offset_t lastaddr;
725         int nsegs, error, first, i;
726         bus_size_t resid;
727         struct iovec *iov;
728         struct thread *td = NULL;
729
730         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
731                 ("bus_dmamap_load_uio: No support for bounce pages!"));
732
733         resid = uio->uio_resid;
734         iov = uio->uio_iov;
735
736         if (uio->uio_segflg == UIO_USERSPACE) {
737                 td = uio->uio_td;
738                 KASSERT(td != NULL && td->td_proc != NULL,
739                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
740         }
741
742         nsegs = 0;
743         error = 0;
744         first = 1;
745         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
746                 /*
747                  * Now at the first iovec to load.  Load each iovec
748                  * until we have exhausted the residual count.
749                  */
750                 bus_size_t minlen =
751                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
752                 caddr_t addr = (caddr_t) iov[i].iov_base;
753
754                 error = _bus_dmamap_load_buffer(dmat,
755                                 addr, minlen,
756                                 td, flags, &lastaddr, &nsegs, first);
757                 first = 0;
758
759                 resid -= minlen;
760         }
761
762         if (error) {
763                 /* force "no valid mappings" in callback */
764                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
765         } else {
766                 (*callback)(callback_arg, dmat->segments,
767                             nsegs+1, uio->uio_resid, error);
768         }
769         return (error);
770 }
771
772 /*
773  * Release the mapping held by map.
774  */
775 void
776 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
777 {
778         struct bounce_page *bpage;
779
780         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
781                 STAILQ_REMOVE_HEAD(&map->bpages, links);
782                 free_bounce_page(dmat, bpage);
783         }
784 }
785
786 void
787 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
788 {
789         struct bounce_page *bpage;
790
791         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
792                 
793                 /*
794                  * Handle data bouncing.  We might also
795                  * want to add support for invalidating
796                  * the caches on broken hardware
797                  */
798                 switch (op) {
799                 case BUS_DMASYNC_PREWRITE:
800                         while (bpage != NULL) {
801                                 bcopy((void *)bpage->datavaddr,
802                                       (void *)bpage->vaddr,
803                                       bpage->datacount);
804                                 bpage = STAILQ_NEXT(bpage, links);
805                         }
806                         break;
807
808                 case BUS_DMASYNC_POSTREAD:
809                         while (bpage != NULL) {
810                                 bcopy((void *)bpage->vaddr,
811                                       (void *)bpage->datavaddr,
812                                       bpage->datacount);
813                                 bpage = STAILQ_NEXT(bpage, links);
814                         }
815                         break;
816                 case BUS_DMASYNC_PREREAD:
817                 case BUS_DMASYNC_POSTWRITE:
818                         /* No-ops */
819                         break;
820                 }
821         }
822 }
823
824 static int
825 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
826 {
827         int count;
828
829         count = 0;
830         if (total_bpages == 0) {
831                 STAILQ_INIT(&bounce_page_list);
832                 STAILQ_INIT(&bounce_map_waitinglist);
833                 STAILQ_INIT(&bounce_map_callbacklist);
834         }
835         
836         while (numpages > 0) {
837                 struct bounce_page *bpage;
838
839                 bpage = (struct bounce_page *)kmalloc(sizeof(*bpage), M_DEVBUF,
840                                                      M_INTWAIT | M_ZERO);
841
842                 if (bpage == NULL)
843                         break;
844                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
845                                                          M_NOWAIT, 0ul,
846                                                          dmat->lowaddr,
847                                                          PAGE_SIZE,
848                                                          0);
849                 if (bpage->vaddr == 0) {
850                         kfree(bpage, M_DEVBUF);
851                         break;
852                 }
853                 bpage->busaddr = pmap_kextract(bpage->vaddr);
854                 crit_enter();
855                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
856                 total_bpages++;
857                 free_bpages++;
858                 crit_exit();
859                 count++;
860                 numpages--;
861         }
862         return (count);
863 }
864
865 static int
866 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
867 {
868         int pages;
869
870         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
871         free_bpages -= pages;
872         reserved_bpages += pages;
873         map->pagesreserved += pages;
874         pages = map->pagesneeded - map->pagesreserved;
875
876         return (pages);
877 }
878
879 static bus_addr_t
880 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
881                 bus_size_t size)
882 {
883         struct bounce_page *bpage;
884
885         if (map->pagesneeded == 0)
886                 panic("add_bounce_page: map doesn't need any pages");
887         map->pagesneeded--;
888
889         if (map->pagesreserved == 0)
890                 panic("add_bounce_page: map doesn't need any pages");
891         map->pagesreserved--;
892
893         crit_enter();
894         bpage = STAILQ_FIRST(&bounce_page_list);
895         if (bpage == NULL)
896                 panic("add_bounce_page: free page list is empty");
897
898         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
899         reserved_bpages--;
900         active_bpages++;
901         crit_exit();
902
903         bpage->datavaddr = vaddr;
904         bpage->datacount = size;
905         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
906         return (bpage->busaddr);
907 }
908
909 static void
910 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
911 {
912         struct bus_dmamap *map;
913
914         bpage->datavaddr = 0;
915         bpage->datacount = 0;
916
917         crit_enter();
918         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
919         free_bpages++;
920         active_bpages--;
921         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
922                 if (reserve_bounce_pages(map->dmat, map) == 0) {
923                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
924                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
925                                            map, links);
926                         busdma_swi_pending = 1;
927                         setsoftvm();
928                 }
929         }
930         crit_exit();
931 }
932
933 void
934 busdma_swi(void)
935 {
936         struct bus_dmamap *map;
937
938         crit_enter();
939         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
940                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
941                 crit_exit();
942                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
943                                 map->callback, map->callback_arg, /*flags*/0);
944                 crit_enter();
945         }
946         crit_exit();
947 }