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 1.12 2005/01/18 14:02:05 joerg 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
  36 #include <vm/vm.h>
  37 #include <vm/vm_page.h>
  38
  39 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  40 #include <sys/proc.h>
  41 #include <sys/lock.h>
  42 #include <vm/vm_map.h>
  43
  44 #include <machine/bus.h>
  45 #include <machine/md_var.h>
  46
  47 #define MAX_BPAGES 128
  48
  49 struct bus_dma_tag {
  50         bus_dma_tag_t     parent;
  51         bus_size_t        alignment;
  52         bus_size_t        boundary;
  53         bus_addr_t        lowaddr;
  54         bus_addr_t        highaddr;
  55         bus_dma_filter_t *filter;
  56         void             *filterarg;
  57         bus_size_t        maxsize;
  58         u_int             nsegments;
  59         bus_size_t        maxsegsz;
  60         int               flags;
  61         int               ref_count;
  62         int               map_count;
  63         bus_dma_segment_t *segments;
  64 };
  65
  66 struct bounce_page {
  67         vm_offset_t     vaddr;          /* kva of bounce buffer */
  68         bus_addr_t      busaddr;        /* Physical address */
  69         vm_offset_t     datavaddr;      /* kva of client data */
  70         bus_size_t      datacount;      /* client data count */
  71         STAILQ_ENTRY(bounce_page) links;
  72 };
  73
  74 int busdma_swi_pending;
  75
  76 static STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  77 static int free_bpages;
  78 static int reserved_bpages;
  79 static int active_bpages;
  80 static int total_bpages;
  81 static bus_addr_t bounce_lowaddr = BUS_SPACE_MAXADDR;
  82
  83 struct bus_dmamap {
  84         struct bp_list         bpages;
  85         int                    pagesneeded;
  86         int                    pagesreserved;
  87         bus_dma_tag_t          dmat;
  88         void                  *buf;             /* unmapped buffer pointer */
  89         bus_size_t             buflen;          /* unmapped buffer length */
  90         bus_dmamap_callback_t *callback;
  91         void                  *callback_arg;
  92         STAILQ_ENTRY(bus_dmamap) links;
  93 };
  94
  95 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
  96 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
  97 static struct bus_dmamap nobounce_dmamap;
  98
  99 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 100 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map);
 101 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 102                                    vm_offset_t vaddr, bus_size_t size);
 103 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 104 static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 105
 106 static __inline int
 107 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 108 {
 109         int retval;
 110
 111         retval = 0;
 112         do {
 113                 if (paddr > dmat->lowaddr
 114                  && paddr <= dmat->highaddr
 115                  && (dmat->filter == NULL
 116                   || (*dmat->filter)(dmat->filterarg, paddr) != 0))
 117                         retval = 1;
 118
 119                 dmat = dmat->parent;
 120         } while (retval == 0 && dmat != NULL);
 121         return (retval);
 122 }
 123
 124 #define BUS_DMA_MIN_ALLOC_COMP BUS_DMA_BUS4
 125 /*
 126  * Allocate a device specific dma_tag.
 127  */
 128 int
 129 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 130                    bus_size_t boundary, bus_addr_t lowaddr,
 131                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 132                    void *filterarg, bus_size_t maxsize, int nsegments,
 133                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 134 {
 135         bus_dma_tag_t newtag;
 136         int error = 0;
 137
 138         /* Return a NULL tag on failure */
 139         *dmat = NULL;
 140
 141         newtag = malloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT);
 142
 143         newtag->parent = parent;
 144         newtag->alignment = alignment;
 145         newtag->boundary = boundary;
 146         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 147         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 148         newtag->filter = filter;
 149         newtag->filterarg = filterarg;
 150         newtag->maxsize = maxsize;
 151         newtag->nsegments = nsegments;
 152         newtag->maxsegsz = maxsegsz;
 153         newtag->flags = flags;
 154         newtag->ref_count = 1; /* Count ourself */
 155         newtag->map_count = 0;
 156         newtag->segments = NULL;
 157
 158         /* Take into account any restrictions imposed by our parent tag */
 159         if (parent != NULL) {
 160                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 161                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 162                 /*
 163                  * XXX Not really correct??? Probably need to honor boundary
 164                  *     all the way up the inheritence chain.
 165                  */
 166                 newtag->boundary = MAX(parent->boundary, newtag->boundary);
 167                 if (newtag->filter == NULL) {
 168                         /*
 169                          * Short circuit looking at our parent directly
 170                          * since we have encapsulated all of its information
 171                          */
 172                         newtag->filter = parent->filter;
 173                         newtag->filterarg = parent->filterarg;
 174                         newtag->parent = parent->parent;
 175                 }
 176                 if (newtag->parent != NULL) {
 177                         parent->ref_count++;
 178                 }
 179         }
 180
 181         if (newtag->lowaddr < ptoa(Maxmem) &&
 182             (flags & BUS_DMA_ALLOCNOW) != 0) {
 183                 /* Must bounce */
 184
 185                 if (lowaddr > bounce_lowaddr) {
 186                         /*
 187                          * Go through the pool and kill any pages
 188                          * that don't reside below lowaddr.
 189                          */
 190                         panic("bus_dma_tag_create: page reallocation "
 191                               "not implemented");
 192                 }
 193                 if (ptoa(total_bpages) < maxsize) {
 194                         int pages;
 195
 196                         pages = atop(maxsize) - total_bpages;
 197
 198                         /* Add pages to our bounce pool */
 199                         if (alloc_bounce_pages(newtag, pages) < pages)
 200                                 error = ENOMEM;
 201                 }
 202                 /* Performed initial allocation */
 203                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 204         }
 205
 206         if (error != 0) {
 207                 free(newtag, M_DEVBUF);
 208         } else {
 209                 *dmat = newtag;
 210         }
 211         return (error);
 212 }
 213
 214 int
 215 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 216 {
 217         if (dmat != NULL) {
 218
 219                 if (dmat->map_count != 0)
 220                         return (EBUSY);
 221
 222                 while (dmat != NULL) {
 223                         bus_dma_tag_t parent;
 224
 225                         parent = dmat->parent;
 226                         dmat->ref_count--;
 227                         if (dmat->ref_count == 0) {
 228                                 if (dmat->segments != NULL)
 229                                         free(dmat->segments, M_DEVBUF);
 230                                 free(dmat, M_DEVBUF);
 231                                 /*
 232                                  * Last reference count, so
 233                                  * release our reference
 234                                  * count on our parent.
 235                                  */
 236                                 dmat = parent;
 237                         } else
 238                                 dmat = NULL;
 239                 }
 240         }
 241         return (0);
 242 }
 243
 244 /*
 245  * Allocate a handle for mapping from kva/uva/physical
 246  * address space into bus device space.
 247  */
 248 int
 249 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 250 {
 251         int error;
 252
 253         error = 0;
 254
 255         if (dmat->segments == NULL) {
 256                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 257                 dmat->segments = malloc(sizeof(bus_dma_segment_t) *
 258                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 259         }
 260
 261         if (dmat->lowaddr < ptoa(Maxmem)) {
 262                 /* Must bounce */
 263                 int maxpages;
 264
 265                 *mapp = malloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT);
 266                 if (*mapp == NULL) {
 267                         return (ENOMEM);
 268                 } else {
 269                         /* Initialize the new map */
 270                         bzero(*mapp, sizeof(**mapp));
 271                         STAILQ_INIT(&((*mapp)->bpages));
 272                 }
 273                 /*
 274                  * Attempt to add pages to our pool on a per-instance
 275                  * basis up to a sane limit.
 276                  */
 277                 maxpages = MIN(MAX_BPAGES, Maxmem - atop(dmat->lowaddr));
 278                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 279                  || (dmat->map_count > 0
 280                   && total_bpages < maxpages)) {
 281                         int pages;
 282
 283                         if (dmat->lowaddr > bounce_lowaddr) {
 284                                 /*
 285                                  * Go through the pool and kill any pages
 286                                  * that don't reside below lowaddr.
 287                                  */
 288                                 panic("bus_dmamap_create: page reallocation "
 289                                       "not implemented");
 290                         }
 291                         pages = atop(dmat->maxsize);
 292                         pages = MIN(maxpages - total_bpages, pages);
 293                         error = alloc_bounce_pages(dmat, pages);
 294
 295                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 296                                 if (error == 0)
 297                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 298                         } else {
 299                                 error = 0;
 300                         }
 301                 }
 302         } else {
 303                 *mapp = NULL;
 304         }
 305         if (error == 0)
 306                 dmat->map_count++;
 307         return (error);
 308 }
 309
 310 /*
 311  * Destroy a handle for mapping from kva/uva/physical
 312  * address space into bus device space.
 313  */
 314 int
 315 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 316 {
 317         if (map != NULL) {
 318                 if (STAILQ_FIRST(&map->bpages) != NULL)
 319                         return (EBUSY);
 320                 free(map, M_DEVBUF);
 321         }
 322         dmat->map_count--;
 323         return (0);
 324 }
 325
 326
 327 /*
 328  * Allocate a piece of memory that can be efficiently mapped into
 329  * bus device space based on the constraints lited in the dma tag.
 330  *
 331  * mapp is degenerate.  By definition this allocation should not require
 332  * bounce buffers so do not allocate a dma map.
 333  */
 334 int
 335 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 336                  bus_dmamap_t *mapp)
 337 {
 338         int mflags;
 339         /* If we succeed, no mapping/bouncing will be required */
 340         *mapp = NULL;
 341
 342         if (dmat->segments == NULL) {
 343                 KKASSERT(dmat->nsegments < 16384);
 344                 dmat->segments = malloc(sizeof(bus_dma_segment_t) *
 345                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 346         }
 347
 348         if (flags & BUS_DMA_NOWAIT)
 349                 mflags = M_NOWAIT;
 350         else
 351                 mflags = M_WAITOK;
 352         if (flags & BUS_DMA_ZERO)
 353                 mflags |= M_ZERO;
 354
 355         if ((dmat->maxsize <= PAGE_SIZE) &&
 356             dmat->lowaddr >= ptoa(Maxmem)) {
 357                 *vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
 358                 /*
 359                  * XXX Check whether the allocation crossed a page boundary
 360                  * and retry with power-of-2 alignment in that case.
 361                  */
 362                 if ((((intptr_t)*vaddr) & PAGE_MASK) !=
 363                     (((intptr_t)*vaddr + dmat->maxsize) & PAGE_MASK)) {
 364                         size_t size;
 365                         free(*vaddr, M_DEVBUF);
 366                         /* XXX check for overflow? */
 367                         for (size = 1; size <= dmat->maxsize; size <<= 1)
 368                                 ;
 369                         *vaddr = malloc(size, M_DEVBUF, mflags);
 370                 }
 371         } else {
 372                 /*
 373                  * XXX Use Contigmalloc until it is merged into this facility
 374                  *     and handles multi-seg allocations.  Nobody is doing
 375                  *     multi-seg allocations yet though.
 376                  */
 377                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 378                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 379                     dmat->boundary);
 380         }
 381         if (*vaddr == NULL)
 382                 return (ENOMEM);
 383         return (0);
 384 }
 385
 386 /*
 387  * Free a piece of memory and it's allociated dmamap, that was allocated
 388  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 389  */
 390 void
 391 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 392 {
 393         /*
 394          * dmamem does not need to be bounced, so the map should be
 395          * NULL
 396          */
 397         if (map != NULL)
 398                 panic("bus_dmamem_free: Invalid map freed\n");
 399         if ((dmat->maxsize <= PAGE_SIZE) &&
 400             dmat->lowaddr >= ptoa(Maxmem))
 401                 free(vaddr, M_DEVBUF);
 402         else
 403                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 404 }
 405
 406 #define BUS_DMAMAP_NSEGS ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
 407
 408 /*
 409  * Map the buffer buf into bus space using the dmamap map.
 410  */
 411 int
 412 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 413                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 414                 void *callback_arg, int flags)
 415 {
 416         vm_offset_t             vaddr;
 417         vm_paddr_t              paddr;
 418         bus_dma_segment_t      *sg;
 419         int                     seg;
 420         int                     error;
 421         vm_paddr_t              nextpaddr;
 422
 423         if (map == NULL)
 424                 map = &nobounce_dmamap;
 425
 426         error = 0;
 427         /*
 428          * If we are being called during a callback, pagesneeded will
 429          * be non-zero, so we can avoid doing the work twice.
 430          */
 431         if (dmat->lowaddr < ptoa(Maxmem) &&
 432             map->pagesneeded == 0) {
 433                 vm_offset_t     vendaddr;
 434
 435                 /*
 436                  * Count the number of bounce pages
 437                  * needed in order to complete this transfer
 438                  */
 439                 vaddr = trunc_page((vm_offset_t)buf);
 440                 vendaddr = (vm_offset_t)buf + buflen;
 441
 442                 while (vaddr < vendaddr) {
 443                         paddr = pmap_kextract(vaddr);
 444                         if (run_filter(dmat, paddr) != 0) {
 445
 446                                 map->pagesneeded++;
 447                         }
 448                         vaddr += PAGE_SIZE;
 449                 }
 450         }
 451
 452         /* Reserve Necessary Bounce Pages */
 453         if (map->pagesneeded != 0) {
 454                 int s;
 455
 456                 s = splhigh();
 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                         splx(s);
 468
 469                         return (EINPROGRESS);
 470                 }
 471                 splx(s);
 472         }
 473
 474         vaddr = (vm_offset_t)buf;
 475         sg = dmat->segments;
 476         seg = 1;
 477         sg->ds_len = 0;
 478
 479         nextpaddr = 0;
 480         do {
 481                 bus_size_t      size;
 482
 483                 paddr = pmap_kextract(vaddr);
 484                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 485                 if (size > buflen)
 486                         size = buflen;
 487
 488                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 489                         paddr = add_bounce_page(dmat, map, vaddr, size);
 490                 }
 491
 492                 if (sg->ds_len == 0) {
 493                         sg->ds_addr = paddr;
 494                         sg->ds_len = size;
 495                 } else if (paddr == nextpaddr) {
 496                         sg->ds_len += size;
 497                 } else {
 498                         /* Go to the next segment */
 499                         sg++;
 500                         seg++;
 501                         if (seg > dmat->nsegments)
 502                                 break;
 503                         sg->ds_addr = paddr;
 504                         sg->ds_len = size;
 505                 }
 506                 vaddr += size;
 507                 nextpaddr = paddr + size;
 508                 buflen -= size;
 509         } while (buflen > 0);
 510
 511         if (buflen != 0) {
 512                 printf("bus_dmamap_load: Too many segs! buf_len = 0x%lx\n",
 513                        (u_long)buflen);
 514                 error = EFBIG;
 515         }
 516
 517         (*callback)(callback_arg, dmat->segments, seg, error);
 518
 519         return (0);
 520 }
 521
 522 /*
 523  * Utility function to load a linear buffer.  lastaddrp holds state
 524  * between invocations (for multiple-buffer loads).  segp contains
 525  * the starting segment on entrace, and the ending segment on exit.
 526  * first indicates if this is the first invocation of this function.
 527  */
 528 static int
 529 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 530                         void *buf, bus_size_t buflen,
 531                         struct thread *td,
 532                         int flags,
 533                         vm_offset_t *lastaddrp,
 534                         int *segp,
 535                         int first)
 536 {
 537         bus_dma_segment_t *segs;
 538         bus_size_t sgsize;
 539         bus_addr_t curaddr, lastaddr, baddr, bmask;
 540         vm_offset_t vaddr = (vm_offset_t)buf;
 541         int seg;
 542         pmap_t pmap;
 543
 544         if (td->td_proc != NULL)
 545                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 546         else
 547                 pmap = NULL;
 548
 549         segs = dmat->segments;
 550         lastaddr = *lastaddrp;
 551         bmask  = ~(dmat->boundary - 1);
 552
 553         for (seg = *segp; buflen > 0 ; ) {
 554                 /*
 555                  * Get the physical address for this segment.
 556                  */
 557                 if (pmap)
 558                         curaddr = pmap_extract(pmap, vaddr);
 559                 else
 560                         curaddr = pmap_kextract(vaddr);
 561
 562                 /*
 563                  * Compute the segment size, and adjust counts.
 564                  */
 565                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
 566                 if (buflen < sgsize)
 567                         sgsize = buflen;
 568
 569                 /*
 570                  * Make sure we don't cross any boundaries.
 571                  */
 572                 if (dmat->boundary > 0) {
 573                         baddr = (curaddr + dmat->boundary) & bmask;
 574                         if (sgsize > (baddr - curaddr))
 575                                 sgsize = (baddr - curaddr);
 576                 }
 577
 578                 /*
 579                  * Insert chunk into a segment, coalescing with
 580                  * previous segment if possible.
 581                  */
 582                 if (first) {
 583                         segs[seg].ds_addr = curaddr;
 584                         segs[seg].ds_len = sgsize;
 585                         first = 0;
 586                 } else {
 587                         if (curaddr == lastaddr &&
 588                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 589                             (dmat->boundary == 0 ||
 590                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 591                                 segs[seg].ds_len += sgsize;
 592                         else {
 593                                 if (++seg >= dmat->nsegments)
 594                                         break;
 595                                 segs[seg].ds_addr = curaddr;
 596                                 segs[seg].ds_len = sgsize;
 597                         }
 598                 }
 599
 600                 lastaddr = curaddr + sgsize;
 601                 vaddr += sgsize;
 602                 buflen -= sgsize;
 603         }
 604
 605         *segp = seg;
 606         *lastaddrp = lastaddr;
 607
 608         /*
 609          * Did we fit?
 610          */
 611         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 612 }
 613
 614 /*
 615  * Like _bus_dmamap_load(), but for mbufs.
 616  */
 617 int
 618 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 619                      struct mbuf *m0,
 620                      bus_dmamap_callback2_t *callback, void *callback_arg,
 621                      int flags)
 622 {
 623         int nsegs, error;
 624
 625         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 626                 ("bus_dmamap_load_mbuf: No support for bounce pages!"));
 627         KASSERT(m0->m_flags & M_PKTHDR,
 628                 ("bus_dmamap_load_mbuf: no packet header"));
 629
 630         nsegs = 0;
 631         error = 0;
 632         if (m0->m_pkthdr.len <= dmat->maxsize) {
 633                 int first = 1;
 634                 vm_offset_t lastaddr = 0;
 635                 struct mbuf *m;
 636
 637                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 638                         if ( m->m_len == 0 )
 639                                 continue;
 640                         error = _bus_dmamap_load_buffer(dmat,
 641                                         m->m_data, m->m_len,
 642                                         curthread, flags, &lastaddr,
 643                                         &nsegs, first);
 644                         first = 0;
 645                 }
 646         } else {
 647                 error = EINVAL;
 648         }
 649
 650         if (error) {
 651                 /* force "no valid mappings" in callback */
 652                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 653         } else {
 654                 (*callback)(callback_arg, dmat->segments,
 655                             nsegs+1, m0->m_pkthdr.len, error);
 656         }
 657         return (error);
 658 }
 659
 660 /*
 661  * Like _bus_dmamap_load(), but for uios.
 662  */
 663 int
 664 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 665                     struct uio *uio,
 666                     bus_dmamap_callback2_t *callback, void *callback_arg,
 667                     int flags)
 668 {
 669         vm_offset_t lastaddr;
 670         int nsegs, error, first, i;
 671         bus_size_t resid;
 672         struct iovec *iov;
 673         struct thread *td = NULL;
 674
 675         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 676                 ("bus_dmamap_load_uio: No support for bounce pages!"));
 677
 678         resid = uio->uio_resid;
 679         iov = uio->uio_iov;
 680
 681         if (uio->uio_segflg == UIO_USERSPACE) {
 682                 td = uio->uio_td;
 683                 KASSERT(td != NULL && td->td_proc != NULL,
 684                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 685         }
 686
 687         nsegs = 0;
 688         error = 0;
 689         first = 1;
 690         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 691                 /*
 692                  * Now at the first iovec to load.  Load each iovec
 693                  * until we have exhausted the residual count.
 694                  */
 695                 bus_size_t minlen =
 696                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 697                 caddr_t addr = (caddr_t) iov[i].iov_base;
 698
 699                 error = _bus_dmamap_load_buffer(dmat,
 700                                 addr, minlen,
 701                                 td, flags, &lastaddr, &nsegs, first);
 702                 first = 0;
 703
 704                 resid -= minlen;
 705         }
 706
 707         if (error) {
 708                 /* force "no valid mappings" in callback */
 709                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 710         } else {
 711                 (*callback)(callback_arg, dmat->segments,
 712                             nsegs+1, uio->uio_resid, error);
 713         }
 714         return (error);
 715 }
 716
 717 /*
 718  * Release the mapping held by map.
 719  */
 720 void
 721 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 722 {
 723         struct bounce_page *bpage;
 724
 725         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 726                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 727                 free_bounce_page(dmat, bpage);
 728         }
 729 }
 730
 731 void
 732 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 733 {
 734         struct bounce_page *bpage;
 735
 736         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 737
 738                 /*
 739                  * Handle data bouncing.  We might also
 740                  * want to add support for invalidating
 741                  * the caches on broken hardware
 742                  */
 743                 switch (op) {
 744                 case BUS_DMASYNC_PREWRITE:
 745                         while (bpage != NULL) {
 746                                 bcopy((void *)bpage->datavaddr,
 747                                       (void *)bpage->vaddr,
 748                                       bpage->datacount);
 749                                 bpage = STAILQ_NEXT(bpage, links);
 750                         }
 751                         break;
 752
 753                 case BUS_DMASYNC_POSTREAD:
 754                         while (bpage != NULL) {
 755                                 bcopy((void *)bpage->vaddr,
 756                                       (void *)bpage->datavaddr,
 757                                       bpage->datacount);
 758                                 bpage = STAILQ_NEXT(bpage, links);
 759                         }
 760                         break;
 761                 case BUS_DMASYNC_PREREAD:
 762                 case BUS_DMASYNC_POSTWRITE:
 763                         /* No-ops */
 764                         break;
 765                 }
 766         }
 767 }
 768
 769 static int
 770 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
 771 {
 772         int count;
 773
 774         count = 0;
 775         if (total_bpages == 0) {
 776                 STAILQ_INIT(&bounce_page_list);
 777                 STAILQ_INIT(&bounce_map_waitinglist);
 778                 STAILQ_INIT(&bounce_map_callbacklist);
 779         }
 780
 781         while (numpages > 0) {
 782                 struct bounce_page *bpage;
 783                 int s;
 784
 785                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
 786                                                      M_INTWAIT);
 787
 788                 if (bpage == NULL)
 789                         break;
 790                 bzero(bpage, sizeof(*bpage));
 791                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
 792                                                          M_NOWAIT, 0ul,
 793                                                          dmat->lowaddr,
 794                                                          PAGE_SIZE,
 795                                                          0);
 796                 if (bpage->vaddr == NULL) {
 797                         free(bpage, M_DEVBUF);
 798                         break;
 799                 }
 800                 bpage->busaddr = pmap_kextract(bpage->vaddr);
 801                 s = splhigh();
 802                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
 803                 total_bpages++;
 804                 free_bpages++;
 805                 splx(s);
 806                 count++;
 807                 numpages--;
 808         }
 809         return (count);
 810 }
 811
 812 static int
 813 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
 814 {
 815         int pages;
 816
 817         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
 818         free_bpages -= pages;
 819         reserved_bpages += pages;
 820         map->pagesreserved += pages;
 821         pages = map->pagesneeded - map->pagesreserved;
 822
 823         return (pages);
 824 }
 825
 826 static bus_addr_t
 827 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 828                 bus_size_t size)
 829 {
 830         int s;
 831         struct bounce_page *bpage;
 832
 833         if (map->pagesneeded == 0)
 834                 panic("add_bounce_page: map doesn't need any pages");
 835         map->pagesneeded--;
 836
 837         if (map->pagesreserved == 0)
 838                 panic("add_bounce_page: map doesn't need any pages");
 839         map->pagesreserved--;
 840
 841         s = splhigh();
 842         bpage = STAILQ_FIRST(&bounce_page_list);
 843         if (bpage == NULL)
 844                 panic("add_bounce_page: free page list is empty");
 845
 846         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
 847         reserved_bpages--;
 848         active_bpages++;
 849         splx(s);
 850
 851         bpage->datavaddr = vaddr;
 852         bpage->datacount = size;
 853         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 854         return (bpage->busaddr);
 855 }
 856
 857 static void
 858 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 859 {
 860         int s;
 861         struct bus_dmamap *map;
 862
 863         bpage->datavaddr = 0;
 864         bpage->datacount = 0;
 865
 866         s = splhigh();
 867         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
 868         free_bpages++;
 869         active_bpages--;
 870         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
 871                 if (reserve_bounce_pages(map->dmat, map) == 0) {
 872                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
 873                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
 874                                            map, links);
 875                         busdma_swi_pending = 1;
 876                         setsoftvm();
 877                 }
 878         }
 879         splx(s);
 880 }
 881
 882 void
 883 busdma_swi()
 884 {
 885         int s;
 886         struct bus_dmamap *map;
 887
 888         s = splhigh();
 889         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
 890                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
 891                 splx(s);
 892                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
 893                                 map->callback, map->callback_arg, /*flags*/0);
 894                 s = splhigh();
 895         }
 896         splx(s);
 897 }