sys/x86/x86/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
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/malloc.h>
  33 #include <sys/bus.h>
  34 #include <sys/interrupt.h>
  35 #include <sys/kernel.h>
  36 #include <sys/ktr.h>
  37 #include <sys/lock.h>
  38 #include <sys/proc.h>
  39 #include <sys/memdesc.h>
  40 #include <sys/mutex.h>
  41 #include <sys/sysctl.h>
  42 #include <sys/uio.h>
  43
  44 #include <vm/vm.h>
  45 #include <vm/vm_extern.h>
  46 #include <vm/vm_kern.h>
  47 #include <vm/vm_page.h>
  48 #include <vm/vm_map.h>
  49
  50 #include <machine/atomic.h>
  51 #include <machine/bus.h>
  52 #include <machine/md_var.h>
  53 #include <machine/specialreg.h>
  54
  55 #ifdef __i386__
  56 #define MAX_BPAGES 512
  57 #else
  58 #define MAX_BPAGES 8192
  59 #endif
  60 #define BUS_DMA_COULD_BOUNCE    BUS_DMA_BUS3
  61 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  62
  63 struct bounce_zone;
  64
  65 struct bus_dma_tag {
  66         bus_dma_tag_t     parent;
  67         bus_size_t        alignment;
  68         bus_size_t        boundary;
  69         bus_addr_t        lowaddr;
  70         bus_addr_t        highaddr;
  71         bus_dma_filter_t *filter;
  72         void             *filterarg;
  73         bus_size_t        maxsize;
  74         u_int             nsegments;
  75         bus_size_t        maxsegsz;
  76         int               flags;
  77         int               ref_count;
  78         int               map_count;
  79         bus_dma_lock_t   *lockfunc;
  80         void             *lockfuncarg;
  81         bus_dma_segment_t *segments;
  82         struct bounce_zone *bounce_zone;
  83 };
  84
  85 struct bounce_page {
  86         vm_offset_t     vaddr;          /* kva of bounce buffer */
  87         bus_addr_t      busaddr;        /* Physical address */
  88         vm_offset_t     datavaddr;      /* kva of client data */
  89         bus_addr_t      dataaddr;       /* client physical address */
  90         bus_size_t      datacount;      /* client data count */
  91         STAILQ_ENTRY(bounce_page) links;
  92 };
  93
  94 int busdma_swi_pending;
  95
  96 struct bounce_zone {
  97         STAILQ_ENTRY(bounce_zone) links;
  98         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  99         int             total_bpages;
 100         int             free_bpages;
 101         int             reserved_bpages;
 102         int             active_bpages;
 103         int             total_bounced;
 104         int             total_deferred;
 105         int             map_count;
 106         bus_size_t      alignment;
 107         bus_addr_t      lowaddr;
 108         char            zoneid[8];
 109         char            lowaddrid[20];
 110         struct sysctl_ctx_list sysctl_tree;
 111         struct sysctl_oid *sysctl_tree_top;
 112 };
 113
 114 static struct mtx bounce_lock;
 115 static int total_bpages;
 116 static int busdma_zonecount;
 117 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
 118
 119 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 120 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
 121            "Total bounce pages");
 122
 123 struct bus_dmamap {
 124         struct bp_list         bpages;
 125         int                    pagesneeded;
 126         int                    pagesreserved;
 127         bus_dma_tag_t          dmat;
 128         struct memdesc         mem;
 129         bus_dmamap_callback_t *callback;
 130         void                  *callback_arg;
 131         STAILQ_ENTRY(bus_dmamap) links;
 132 };
 133
 134 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 135 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
 136 static struct bus_dmamap nobounce_dmamap, contig_dmamap;
 137
 138 static void init_bounce_pages(void *dummy);
 139 static int alloc_bounce_zone(bus_dma_tag_t dmat);
 140 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 141 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 142                                 int commit);
 143 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 144                                   vm_offset_t vaddr, bus_addr_t addr,
 145                                   bus_size_t size);
 146 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 147 int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 148 static void _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 149                                     pmap_t pmap, void *buf, bus_size_t buflen,
 150                                     int flags);
 151 static void _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 152                                    vm_paddr_t buf, bus_size_t buflen,
 153                                    int flags);
 154 static int _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 155                                      int flags);
 156
 157 #ifdef XEN
 158 #undef pmap_kextract
 159 #define pmap_kextract pmap_kextract_ma
 160 #endif
 161
 162 /*
 163  * Return true if a match is made.
 164  *
 165  * To find a match walk the chain of bus_dma_tag_t's looking for 'paddr'.
 166  *
 167  * If paddr is within the bounds of the dma tag then call the filter callback
 168  * to check for a match, if there is no filter callback then assume a match.
 169  */
 170 int
 171 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 172 {
 173         int retval;
 174
 175         retval = 0;
 176
 177         do {
 178                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr)
 179                  || ((paddr & (dmat->alignment - 1)) != 0))
 180                  && (dmat->filter == NULL
 181                   || (*dmat->filter)(dmat->filterarg, paddr) != 0))
 182                         retval = 1;
 183
 184                 dmat = dmat->parent;
 185         } while (retval == 0 && dmat != NULL);
 186         return (retval);
 187 }
 188
 189 /*
 190  * Convenience function for manipulating driver locks from busdma (during
 191  * busdma_swi, for example).  Drivers that don't provide their own locks
 192  * should specify &Giant to dmat->lockfuncarg.  Drivers that use their own
 193  * non-mutex locking scheme don't have to use this at all.
 194  */
 195 void
 196 busdma_lock_mutex(void *arg, bus_dma_lock_op_t op)
 197 {
 198         struct mtx *dmtx;
 199
 200         dmtx = (struct mtx *)arg;
 201         switch (op) {
 202         case BUS_DMA_LOCK:
 203                 mtx_lock(dmtx);
 204                 break;
 205         case BUS_DMA_UNLOCK:
 206                 mtx_unlock(dmtx);
 207                 break;
 208         default:
 209                 panic("Unknown operation 0x%x for busdma_lock_mutex!", op);
 210         }
 211 }
 212
 213 /*
 214  * dflt_lock should never get called.  It gets put into the dma tag when
 215  * lockfunc == NULL, which is only valid if the maps that are associated
 216  * with the tag are meant to never be defered.
 217  * XXX Should have a way to identify which driver is responsible here.
 218  */
 219 static void
 220 dflt_lock(void *arg, bus_dma_lock_op_t op)
 221 {
 222         panic("driver error: busdma dflt_lock called");
 223 }
 224
 225 /*
 226  * Allocate a device specific dma_tag.
 227  */
 228 int
 229 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 230                    bus_size_t boundary, bus_addr_t lowaddr,
 231                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 232                    void *filterarg, bus_size_t maxsize, int nsegments,
 233                    bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
 234                    void *lockfuncarg, bus_dma_tag_t *dmat)
 235 {
 236         bus_dma_tag_t newtag;
 237         int error = 0;
 238
 239         /* Always enforce at least a 4GB (2GB for PAE) boundary. */
 240 #if defined(__amd64__)
 241         if (boundary == 0 || boundary > ((bus_addr_t)1 << 32))
 242                 boundary = (bus_size_t)1 << 32;
 243 #elif defined(PAE)
 244         if (boundary == 0 || boundary > ((bus_addr_t)1 << 31))
 245                 boundary = (bus_size_t)1 << 31;
 246 #endif
 247         /* Basic sanity checking */
 248         if (boundary != 0 && boundary < maxsegsz)
 249                 maxsegsz = boundary;
 250
 251         if (maxsegsz == 0) {
 252                 return (EINVAL);
 253         }
 254
 255         /* Return a NULL tag on failure */
 256         *dmat = NULL;
 257
 258         newtag = (bus_dma_tag_t)malloc(sizeof(*newtag), M_DEVBUF,
 259             M_ZERO | M_NOWAIT);
 260         if (newtag == NULL) {
 261                 CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
 262                     __func__, newtag, 0, ENOMEM);
 263                 return (ENOMEM);
 264         }
 265
 266         newtag->parent = parent;
 267         newtag->alignment = alignment;
 268         newtag->boundary = boundary;
 269         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 270         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 271         newtag->filter = filter;
 272         newtag->filterarg = filterarg;
 273         newtag->maxsize = maxsize;
 274         newtag->nsegments = nsegments;
 275         newtag->maxsegsz = maxsegsz;
 276         newtag->flags = flags;
 277         newtag->ref_count = 1; /* Count ourself */
 278         newtag->map_count = 0;
 279         if (lockfunc != NULL) {
 280                 newtag->lockfunc = lockfunc;
 281                 newtag->lockfuncarg = lockfuncarg;
 282         } else {
 283                 newtag->lockfunc = dflt_lock;
 284                 newtag->lockfuncarg = NULL;
 285         }
 286         newtag->segments = NULL;
 287
 288         /* Take into account any restrictions imposed by our parent tag */
 289         if (parent != NULL) {
 290                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 291                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 292                 if (newtag->boundary == 0)
 293                         newtag->boundary = parent->boundary;
 294                 else if (parent->boundary != 0)
 295                         newtag->boundary = MIN(parent->boundary,
 296                                                newtag->boundary);
 297                 if ((newtag->filter != NULL) ||
 298                     ((parent->flags & BUS_DMA_COULD_BOUNCE) != 0))
 299                         newtag->flags |= BUS_DMA_COULD_BOUNCE;
 300                 if (newtag->filter == NULL) {
 301                         /*
 302                          * Short circuit looking at our parent directly
 303                          * since we have encapsulated all of its information
 304                          */
 305                         newtag->filter = parent->filter;
 306                         newtag->filterarg = parent->filterarg;
 307                         newtag->parent = parent->parent;
 308                 }
 309                 if (newtag->parent != NULL)
 310                         atomic_add_int(&parent->ref_count, 1);
 311         }
 312
 313         if (newtag->lowaddr < ptoa((vm_paddr_t)Maxmem)
 314          || newtag->alignment > 1)
 315                 newtag->flags |= BUS_DMA_COULD_BOUNCE;
 316
 317         if (((newtag->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 318             (flags & BUS_DMA_ALLOCNOW) != 0) {
 319                 struct bounce_zone *bz;
 320
 321                 /* Must bounce */
 322
 323                 if ((error = alloc_bounce_zone(newtag)) != 0) {
 324                         free(newtag, M_DEVBUF);
 325                         return (error);
 326                 }
 327                 bz = newtag->bounce_zone;
 328
 329                 if (ptoa(bz->total_bpages) < maxsize) {
 330                         int pages;
 331
 332                         pages = atop(maxsize) - bz->total_bpages;
 333
 334                         /* Add pages to our bounce pool */
 335                         if (alloc_bounce_pages(newtag, pages) < pages)
 336                                 error = ENOMEM;
 337                 }
 338                 /* Performed initial allocation */
 339                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 340         }
 341
 342         if (error != 0) {
 343                 free(newtag, M_DEVBUF);
 344         } else {
 345                 *dmat = newtag;
 346         }
 347         CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
 348             __func__, newtag, (newtag != NULL ? newtag->flags : 0), error);
 349         return (error);
 350 }
 351
 352 int
 353 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 354 {
 355         bus_dma_tag_t dmat_copy;
 356         int error;
 357
 358         error = 0;
 359         dmat_copy = dmat;
 360
 361         if (dmat != NULL) {
 362
 363                 if (dmat->map_count != 0) {
 364                         error = EBUSY;
 365                         goto out;
 366                 }
 367
 368                 while (dmat != NULL) {
 369                         bus_dma_tag_t parent;
 370
 371                         parent = dmat->parent;
 372                         atomic_subtract_int(&dmat->ref_count, 1);
 373                         if (dmat->ref_count == 0) {
 374                                 if (dmat->segments != NULL)
 375                                         free(dmat->segments, M_DEVBUF);
 376                                 free(dmat, M_DEVBUF);
 377                                 /*
 378                                  * Last reference count, so
 379                                  * release our reference
 380                                  * count on our parent.
 381                                  */
 382                                 dmat = parent;
 383                         } else
 384                                 dmat = NULL;
 385                 }
 386         }
 387 out:
 388         CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
 389         return (error);
 390 }
 391
 392 /*
 393  * Allocate a handle for mapping from kva/uva/physical
 394  * address space into bus device space.
 395  */
 396 int
 397 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 398 {
 399         int error;
 400
 401         error = 0;
 402
 403         if (dmat->segments == NULL) {
 404                 dmat->segments = (bus_dma_segment_t *)malloc(
 405                     sizeof(bus_dma_segment_t) * dmat->nsegments, M_DEVBUF,
 406                     M_NOWAIT);
 407                 if (dmat->segments == NULL) {
 408                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 409                             __func__, dmat, ENOMEM);
 410                         return (ENOMEM);
 411                 }
 412         }
 413
 414         /*
 415          * Bouncing might be required if the driver asks for an active
 416          * exclusion region, a data alignment that is stricter than 1, and/or
 417          * an active address boundary.
 418          */
 419         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 420
 421                 /* Must bounce */
 422                 struct bounce_zone *bz;
 423                 int maxpages;
 424
 425                 if (dmat->bounce_zone == NULL) {
 426                         if ((error = alloc_bounce_zone(dmat)) != 0)
 427                                 return (error);
 428                 }
 429                 bz = dmat->bounce_zone;
 430
 431                 *mapp = (bus_dmamap_t)malloc(sizeof(**mapp), M_DEVBUF,
 432                                              M_NOWAIT | M_ZERO);
 433                 if (*mapp == NULL) {
 434                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 435                             __func__, dmat, ENOMEM);
 436                         return (ENOMEM);
 437                 }
 438
 439                 /* Initialize the new map */
 440                 STAILQ_INIT(&((*mapp)->bpages));
 441
 442                 /*
 443                  * Attempt to add pages to our pool on a per-instance
 444                  * basis up to a sane limit.
 445                  */
 446                 if (dmat->alignment > 1)
 447                         maxpages = MAX_BPAGES;
 448                 else
 449                         maxpages = MIN(MAX_BPAGES, Maxmem -atop(dmat->lowaddr));
 450                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 451                  || (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 452                         int pages;
 453
 454                         pages = MAX(atop(dmat->maxsize), 1);
 455                         pages = MIN(maxpages - bz->total_bpages, pages);
 456                         pages = MAX(pages, 1);
 457                         if (alloc_bounce_pages(dmat, pages) < pages)
 458                                 error = ENOMEM;
 459
 460                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 461                                 if (error == 0)
 462                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 463                         } else {
 464                                 error = 0;
 465                         }
 466                 }
 467                 bz->map_count++;
 468         } else {
 469                 *mapp = NULL;
 470         }
 471         if (error == 0)
 472                 dmat->map_count++;
 473         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 474             __func__, dmat, dmat->flags, error);
 475         return (error);
 476 }
 477
 478 /*
 479  * Destroy a handle for mapping from kva/uva/physical
 480  * address space into bus device space.
 481  */
 482 int
 483 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 484 {
 485         if (map != NULL && map != &nobounce_dmamap && map != &contig_dmamap) {
 486                 if (STAILQ_FIRST(&map->bpages) != NULL) {
 487                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 488                             __func__, dmat, EBUSY);
 489                         return (EBUSY);
 490                 }
 491                 if (dmat->bounce_zone)
 492                         dmat->bounce_zone->map_count--;
 493                 free(map, M_DEVBUF);
 494         }
 495         dmat->map_count--;
 496         CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
 497         return (0);
 498 }
 499
 500
 501 /*
 502  * Allocate a piece of memory that can be efficiently mapped into
 503  * bus device space based on the constraints lited in the dma tag.
 504  * A dmamap to for use with dmamap_load is also allocated.
 505  */
 506 int
 507 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 508                  bus_dmamap_t *mapp)
 509 {
 510         vm_memattr_t attr;
 511         int mflags;
 512
 513         if (flags & BUS_DMA_NOWAIT)
 514                 mflags = M_NOWAIT;
 515         else
 516                 mflags = M_WAITOK;
 517
 518         /* If we succeed, no mapping/bouncing will be required */
 519         *mapp = NULL;
 520
 521         if (dmat->segments == NULL) {
 522                 dmat->segments = (bus_dma_segment_t *)malloc(
 523                     sizeof(bus_dma_segment_t) * dmat->nsegments, M_DEVBUF,
 524                     mflags);
 525                 if (dmat->segments == NULL) {
 526                         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 527                             __func__, dmat, dmat->flags, ENOMEM);
 528                         return (ENOMEM);
 529                 }
 530         }
 531         if (flags & BUS_DMA_ZERO)
 532                 mflags |= M_ZERO;
 533         if (flags & BUS_DMA_NOCACHE)
 534                 attr = VM_MEMATTR_UNCACHEABLE;
 535         else
 536                 attr = VM_MEMATTR_DEFAULT;
 537
 538         /*
 539          * XXX:
 540          * (dmat->alignment < dmat->maxsize) is just a quick hack; the exact
 541          * alignment guarantees of malloc need to be nailed down, and the
 542          * code below should be rewritten to take that into account.
 543          *
 544          * In the meantime, we'll warn the user if malloc gets it wrong.
 545          */
 546         if ((dmat->maxsize <= PAGE_SIZE) &&
 547            (dmat->alignment < dmat->maxsize) &&
 548             dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 549             attr == VM_MEMATTR_DEFAULT) {
 550                 *vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);
 551         } else if (dmat->nsegments >= btoc(dmat->maxsize) &&
 552             dmat->alignment <= PAGE_SIZE &&
 553             (dmat->boundary == 0 || dmat->boundary >= dmat->lowaddr)) {
 554                 /* Page-based multi-segment allocations allowed */
 555                 *vaddr = (void *)kmem_alloc_attr(kernel_map, dmat->maxsize,
 556                     mflags, 0ul, dmat->lowaddr, attr);
 557                 *mapp = &contig_dmamap;
 558         } else {
 559                 *vaddr = (void *)kmem_alloc_contig(kernel_map, dmat->maxsize,
 560                     mflags, 0ul, dmat->lowaddr, dmat->alignment ?
 561                     dmat->alignment : 1ul, dmat->boundary, attr);
 562                 *mapp = &contig_dmamap;
 563         }
 564         if (*vaddr == NULL) {
 565                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 566                     __func__, dmat, dmat->flags, ENOMEM);
 567                 return (ENOMEM);
 568         } else if (vtophys(*vaddr) & (dmat->alignment - 1)) {
 569                 printf("bus_dmamem_alloc failed to align memory properly.\n");
 570         }
 571         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 572             __func__, dmat, dmat->flags, 0);
 573         return (0);
 574 }
 575
 576 /*
 577  * Free a piece of memory and it's allociated dmamap, that was allocated
 578  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 579  */
 580 void
 581 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 582 {
 583         /*
 584          * dmamem does not need to be bounced, so the map should be
 585          * NULL if malloc() was used and contig_dmamap if
 586          * kmem_alloc_contig() was used.
 587          */
 588         if (!(map == NULL || map == &contig_dmamap))
 589                 panic("bus_dmamem_free: Invalid map freed\n");
 590         if (map == NULL)
 591                 free(vaddr, M_DEVBUF);
 592         else
 593                 kmem_free(kernel_map, (vm_offset_t)vaddr, dmat->maxsize);
 594         CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat, dmat->flags);
 595 }
 596
 597 static void
 598 _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
 599     bus_size_t buflen, int flags)
 600 {
 601         bus_addr_t curaddr;
 602         bus_size_t sgsize;
 603
 604         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 605                 /*
 606                  * Count the number of bounce pages
 607                  * needed in order to complete this transfer
 608                  */
 609                 curaddr = buf;
 610                 while (buflen != 0) {
 611                         sgsize = MIN(buflen, dmat->maxsegsz);
 612                         if (run_filter(dmat, curaddr)) {
 613                                 sgsize = MIN(sgsize, PAGE_SIZE);
 614                                 map->pagesneeded++;
 615                         }
 616                         curaddr += sgsize;
 617                         buflen -= sgsize;
 618                 }
 619                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 620         }
 621 }
 622
 623 static void
 624 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
 625     void *buf, bus_size_t buflen, int flags)
 626 {
 627         vm_offset_t vaddr;
 628         vm_offset_t vendaddr;
 629         bus_addr_t paddr;
 630
 631         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 632                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 633                     "alignment= %d", dmat->lowaddr, ptoa((vm_paddr_t)Maxmem),
 634                     dmat->boundary, dmat->alignment);
 635                 CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
 636                     map, &nobounce_dmamap, map->pagesneeded);
 637                 /*
 638                  * Count the number of bounce pages
 639                  * needed in order to complete this transfer
 640                  */
 641                 vaddr = (vm_offset_t)buf;
 642                 vendaddr = (vm_offset_t)buf + buflen;
 643
 644                 while (vaddr < vendaddr) {
 645                         bus_size_t sg_len;
 646
 647                         sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
 648                         if (pmap == kernel_pmap)
 649                                 paddr = pmap_kextract(vaddr);
 650                         else
 651                                 paddr = pmap_extract(pmap, vaddr);
 652                         if (run_filter(dmat, paddr) != 0) {
 653                                 sg_len = roundup2(sg_len, dmat->alignment);
 654                                 map->pagesneeded++;
 655                         }
 656                         vaddr += sg_len;
 657                 }
 658                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 659         }
 660 }
 661
 662 static int
 663 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
 664 {
 665
 666         /* Reserve Necessary Bounce Pages */
 667         mtx_lock(&bounce_lock);
 668         if (flags & BUS_DMA_NOWAIT) {
 669                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
 670                         mtx_unlock(&bounce_lock);
 671                         return (ENOMEM);
 672                 }
 673         } else {
 674                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
 675                         /* Queue us for resources */
 676                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 677                         mtx_unlock(&bounce_lock);
 678                         return (EINPROGRESS);
 679                 }
 680         }
 681         mtx_unlock(&bounce_lock);
 682
 683         return (0);
 684 }
 685
 686 /*
 687  * Add a single contiguous physical range to the segment list.
 688  */
 689 static int
 690 _bus_dmamap_addseg(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t curaddr,
 691                    bus_size_t sgsize, bus_dma_segment_t *segs, int *segp)
 692 {
 693         bus_addr_t baddr, bmask;
 694         int seg;
 695
 696         /*
 697          * Make sure we don't cross any boundaries.
 698          */
 699         bmask = ~(dmat->boundary - 1);
 700         if (dmat->boundary > 0) {
 701                 baddr = (curaddr + dmat->boundary) & bmask;
 702                 if (sgsize > (baddr - curaddr))
 703                         sgsize = (baddr - curaddr);
 704         }
 705
 706         /*
 707          * Insert chunk into a segment, coalescing with
 708          * previous segment if possible.
 709          */
 710         seg = *segp;
 711         if (seg == -1) {
 712                 seg = 0;
 713                 segs[seg].ds_addr = curaddr;
 714                 segs[seg].ds_len = sgsize;
 715         } else {
 716                 if (curaddr == segs[seg].ds_addr + segs[seg].ds_len &&
 717                     (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 718                     (dmat->boundary == 0 ||
 719                      (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 720                         segs[seg].ds_len += sgsize;
 721                 else {
 722                         if (++seg >= dmat->nsegments)
 723                                 return (0);
 724                         segs[seg].ds_addr = curaddr;
 725                         segs[seg].ds_len = sgsize;
 726                 }
 727         }
 728         *segp = seg;
 729         return (sgsize);
 730 }
 731
 732 /*
 733  * Utility function to load a physical buffer.  segp contains
 734  * the starting segment on entrace, and the ending segment on exit.
 735  */
 736 int
 737 _bus_dmamap_load_phys(bus_dma_tag_t dmat,
 738                       bus_dmamap_t map,
 739                       vm_paddr_t buf, bus_size_t buflen,
 740                       int flags,
 741                       bus_dma_segment_t *segs,
 742                       int *segp)
 743 {
 744         bus_size_t sgsize;
 745         bus_addr_t curaddr;
 746         int error;
 747
 748         if (map == NULL || map == &contig_dmamap)
 749                 map = &nobounce_dmamap;
 750
 751         if (segs == NULL)
 752                 segs = dmat->segments;
 753
 754         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) {
 755                 _bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
 756                 if (map->pagesneeded != 0) {
 757                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 758                         if (error)
 759                                 return (error);
 760                 }
 761         }
 762
 763         while (buflen > 0) {
 764                 curaddr = buf;
 765                 sgsize = MIN(buflen, dmat->maxsegsz);
 766                 if (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 767                     map->pagesneeded != 0 && run_filter(dmat, curaddr)) {
 768                         sgsize = MIN(sgsize, PAGE_SIZE);
 769                         curaddr = add_bounce_page(dmat, map, 0, curaddr,
 770                                                   sgsize);
 771                 }
 772                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 773                     segp);
 774                 if (sgsize == 0)
 775                         break;
 776                 buf += sgsize;
 777                 buflen -= sgsize;
 778         }
 779
 780         /*
 781          * Did we fit?
 782          */
 783         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 784 }
 785
 786 /*
 787  * Utility function to load a linear buffer.  segp contains
 788  * the starting segment on entrace, and the ending segment on exit.
 789  */
 790 int
 791 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 792                         bus_dmamap_t map,
 793                         void *buf, bus_size_t buflen,
 794                         pmap_t pmap,
 795                         int flags,
 796                         bus_dma_segment_t *segs,
 797                         int *segp)
 798 {
 799         bus_size_t sgsize;
 800         bus_addr_t curaddr;
 801         vm_offset_t vaddr;
 802         int error;
 803
 804         if (map == NULL || map == &contig_dmamap)
 805                 map = &nobounce_dmamap;
 806
 807         if (segs == NULL)
 808                 segs = dmat->segments;
 809
 810         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) {
 811                 _bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
 812                 if (map->pagesneeded != 0) {
 813                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 814                         if (error)
 815                                 return (error);
 816                 }
 817         }
 818
 819         vaddr = (vm_offset_t)buf;
 820
 821         while (buflen > 0) {
 822                 bus_size_t max_sgsize;
 823
 824                 /*
 825                  * Get the physical address for this segment.
 826                  */
 827                 if (pmap == kernel_pmap)
 828                         curaddr = pmap_kextract(vaddr);
 829                 else
 830                         curaddr = pmap_extract(pmap, vaddr);
 831
 832                 /*
 833                  * Compute the segment size, and adjust counts.
 834                  */
 835                 max_sgsize = MIN(buflen, dmat->maxsegsz);
 836                 sgsize = PAGE_SIZE - ((vm_offset_t)curaddr & PAGE_MASK);
 837                 if (((dmat->flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 838                     map->pagesneeded != 0 && run_filter(dmat, curaddr)) {
 839                         sgsize = roundup2(sgsize, dmat->alignment);
 840                         sgsize = MIN(sgsize, max_sgsize);
 841                         curaddr = add_bounce_page(dmat, map, vaddr, curaddr,
 842                                                   sgsize);
 843                 } else {
 844                         sgsize = MIN(sgsize, max_sgsize);
 845                 }
 846                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 847                                             segp);
 848                 if (sgsize == 0)
 849                         break;
 850                 vaddr += sgsize;
 851                 buflen -= sgsize;
 852         }
 853
 854         /*
 855          * Did we fit?
 856          */
 857         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 858 }
 859
 860 void
 861 __bus_dmamap_waitok(bus_dma_tag_t dmat, bus_dmamap_t map,
 862                     struct memdesc *mem, bus_dmamap_callback_t *callback,
 863                     void *callback_arg)
 864 {
 865         if (map != NULL) {
 866                 map->mem = *mem;
 867                 map->dmat = dmat;
 868                 map->callback = callback;
 869                 map->callback_arg = callback_arg;
 870         }
 871 }
 872
 873 bus_dma_segment_t *
 874 _bus_dmamap_complete(bus_dma_tag_t dmat, bus_dmamap_t map,
 875                       bus_dma_segment_t *segs, int nsegs, int error)
 876 {
 877
 878         if (segs == NULL)
 879                 segs = dmat->segments;
 880         return (segs);
 881 }
 882
 883 /*
 884  * Release the mapping held by map.
 885  */
 886 void
 887 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 888 {
 889         struct bounce_page *bpage;
 890
 891         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 892                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 893                 free_bounce_page(dmat, bpage);
 894         }
 895 }
 896
 897 void
 898 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 899 {
 900         struct bounce_page *bpage;
 901
 902         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 903                 /*
 904                  * Handle data bouncing.  We might also
 905                  * want to add support for invalidating
 906                  * the caches on broken hardware
 907                  */
 908                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
 909                     "performing bounce", __func__, op, dmat, dmat->flags);
 910
 911                 if (op & BUS_DMASYNC_PREWRITE) {
 912                         while (bpage != NULL) {
 913                                 if (bpage->datavaddr != 0)
 914                                         bcopy((void *)bpage->datavaddr,
 915                                               (void *)bpage->vaddr,
 916                                               bpage->datacount);
 917                                 else
 918                                         physcopyout(bpage->dataaddr,
 919                                               (void *)bpage->vaddr,
 920                                               bpage->datacount);
 921                                 bpage = STAILQ_NEXT(bpage, links);
 922                         }
 923                         dmat->bounce_zone->total_bounced++;
 924                 }
 925
 926                 if (op & BUS_DMASYNC_POSTREAD) {
 927                         while (bpage != NULL) {
 928                                 if (bpage->datavaddr != 0)
 929                                         bcopy((void *)bpage->vaddr,
 930                                               (void *)bpage->datavaddr,
 931                                               bpage->datacount);
 932                                 else
 933                                         physcopyin((void *)bpage->vaddr,
 934                                               bpage->dataaddr,
 935                                               bpage->datacount);
 936                                 bpage = STAILQ_NEXT(bpage, links);
 937                         }
 938                         dmat->bounce_zone->total_bounced++;
 939                 }
 940         }
 941 }
 942
 943 static void
 944 init_bounce_pages(void *dummy __unused)
 945 {
 946
 947         total_bpages = 0;
 948         STAILQ_INIT(&bounce_zone_list);
 949         STAILQ_INIT(&bounce_map_waitinglist);
 950         STAILQ_INIT(&bounce_map_callbacklist);
 951         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
 952 }
 953 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
 954
 955 static struct sysctl_ctx_list *
 956 busdma_sysctl_tree(struct bounce_zone *bz)
 957 {
 958         return (&bz->sysctl_tree);
 959 }
 960
 961 static struct sysctl_oid *
 962 busdma_sysctl_tree_top(struct bounce_zone *bz)
 963 {
 964         return (bz->sysctl_tree_top);
 965 }
 966
 967 #if defined(__amd64__) || defined(PAE)
 968 #define SYSCTL_ADD_BUS_SIZE_T   SYSCTL_ADD_UQUAD
 969 #else
 970 #define SYSCTL_ADD_BUS_SIZE_T(ctx, parent, nbr, name, flag, ptr, desc)  \
 971         SYSCTL_ADD_UINT(ctx, parent, nbr, name, flag, ptr, 0, desc)
 972 #endif
 973
 974 static int
 975 alloc_bounce_zone(bus_dma_tag_t dmat)
 976 {
 977         struct bounce_zone *bz;
 978
 979         /* Check to see if we already have a suitable zone */
 980         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
 981                 if ((dmat->alignment <= bz->alignment)
 982                  && (dmat->lowaddr >= bz->lowaddr)) {
 983                         dmat->bounce_zone = bz;
 984                         return (0);
 985                 }
 986         }
 987
 988         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
 989             M_NOWAIT | M_ZERO)) == NULL)
 990                 return (ENOMEM);
 991
 992         STAILQ_INIT(&bz->bounce_page_list);
 993         bz->free_bpages = 0;
 994         bz->reserved_bpages = 0;
 995         bz->active_bpages = 0;
 996         bz->lowaddr = dmat->lowaddr;
 997         bz->alignment = MAX(dmat->alignment, PAGE_SIZE);
 998         bz->map_count = 0;
 999         snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1000         busdma_zonecount++;
1001         snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1002         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1003         dmat->bounce_zone = bz;
1004
1005         sysctl_ctx_init(&bz->sysctl_tree);
1006         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
1007             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1008             CTLFLAG_RD, 0, "");
1009         if (bz->sysctl_tree_top == NULL) {
1010                 sysctl_ctx_free(&bz->sysctl_tree);
1011                 return (0);     /* XXX error code? */
1012         }
1013
1014         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1015             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1016             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1017             "Total bounce pages");
1018         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1019             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1020             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1021             "Free bounce pages");
1022         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1023             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1024             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1025             "Reserved bounce pages");
1026         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1027             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1028             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1029             "Active bounce pages");
1030         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1031             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1032             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1033             "Total bounce requests");
1034         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1035             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1036             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1037             "Total bounce requests that were deferred");
1038         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
1039             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1040             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1041         SYSCTL_ADD_BUS_SIZE_T(busdma_sysctl_tree(bz),
1042             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1043             "alignment", CTLFLAG_RD, &bz->alignment, "");
1044
1045         return (0);
1046 }
1047
1048 static int
1049 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
1050 {
1051         struct bounce_zone *bz;
1052         int count;
1053
1054         bz = dmat->bounce_zone;
1055         count = 0;
1056         while (numpages > 0) {
1057                 struct bounce_page *bpage;
1058
1059                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
1060                                                      M_NOWAIT | M_ZERO);
1061
1062                 if (bpage == NULL)
1063                         break;
1064                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1065                                                          M_NOWAIT, 0ul,
1066                                                          bz->lowaddr,
1067                                                          PAGE_SIZE,
1068                                                          0);
1069                 if (bpage->vaddr == 0) {
1070                         free(bpage, M_DEVBUF);
1071                         break;
1072                 }
1073                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1074                 mtx_lock(&bounce_lock);
1075                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1076                 total_bpages++;
1077                 bz->total_bpages++;
1078                 bz->free_bpages++;
1079                 mtx_unlock(&bounce_lock);
1080                 count++;
1081                 numpages--;
1082         }
1083         return (count);
1084 }
1085
1086 static int
1087 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1088 {
1089         struct bounce_zone *bz;
1090         int pages;
1091
1092         mtx_assert(&bounce_lock, MA_OWNED);
1093         bz = dmat->bounce_zone;
1094         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1095         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
1096                 return (map->pagesneeded - (map->pagesreserved + pages));
1097         bz->free_bpages -= pages;
1098         bz->reserved_bpages += pages;
1099         map->pagesreserved += pages;
1100         pages = map->pagesneeded - map->pagesreserved;
1101
1102         return (pages);
1103 }
1104
1105 static bus_addr_t
1106 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1107                 bus_addr_t addr, bus_size_t size)
1108 {
1109         struct bounce_zone *bz;
1110         struct bounce_page *bpage;
1111
1112         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
1113         KASSERT(map != NULL && map != &nobounce_dmamap && map != &contig_dmamap,
1114             ("add_bounce_page: bad map %p", map));
1115
1116         bz = dmat->bounce_zone;
1117         if (map->pagesneeded == 0)
1118                 panic("add_bounce_page: map doesn't need any pages");
1119         map->pagesneeded--;
1120
1121         if (map->pagesreserved == 0)
1122                 panic("add_bounce_page: map doesn't need any pages");
1123         map->pagesreserved--;
1124
1125         mtx_lock(&bounce_lock);
1126         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1127         if (bpage == NULL)
1128                 panic("add_bounce_page: free page list is empty");
1129
1130         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1131         bz->reserved_bpages--;
1132         bz->active_bpages++;
1133         mtx_unlock(&bounce_lock);
1134
1135         if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
1136                 /* Page offset needs to be preserved. */
1137                 bpage->vaddr |= vaddr & PAGE_MASK;
1138                 bpage->busaddr |= vaddr & PAGE_MASK;
1139         }
1140         bpage->datavaddr = vaddr;
1141         bpage->dataaddr = addr;
1142         bpage->datacount = size;
1143         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
1144         return (bpage->busaddr);
1145 }
1146
1147 static void
1148 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1149 {
1150         struct bus_dmamap *map;
1151         struct bounce_zone *bz;
1152
1153         bz = dmat->bounce_zone;
1154         bpage->datavaddr = 0;
1155         bpage->datacount = 0;
1156         if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
1157                 /*
1158                  * Reset the bounce page to start at offset 0.  Other uses
1159                  * of this bounce page may need to store a full page of
1160                  * data and/or assume it starts on a page boundary.
1161                  */
1162                 bpage->vaddr &= ~PAGE_MASK;
1163                 bpage->busaddr &= ~PAGE_MASK;
1164         }
1165
1166         mtx_lock(&bounce_lock);
1167         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1168         bz->free_bpages++;
1169         bz->active_bpages--;
1170         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
1171                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1172                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
1173                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
1174                                            map, links);
1175                         busdma_swi_pending = 1;
1176                         bz->total_deferred++;
1177                         swi_sched(vm_ih, 0);
1178                 }
1179         }
1180         mtx_unlock(&bounce_lock);
1181 }
1182
1183 void
1184 busdma_swi(void)
1185 {
1186         bus_dma_tag_t dmat;
1187         struct bus_dmamap *map;
1188
1189         mtx_lock(&bounce_lock);
1190         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1191                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1192                 mtx_unlock(&bounce_lock);
1193                 dmat = map->dmat;
1194                 (dmat->lockfunc)(dmat->lockfuncarg, BUS_DMA_LOCK);
1195                 bus_dmamap_load_mem(map->dmat, map, &map->mem,
1196                                 map->callback, map->callback_arg,
1197                                 BUS_DMA_WAITOK);
1198                 (dmat->lockfunc)(dmat->lockfuncarg, BUS_DMA_UNLOCK);
1199                 mtx_lock(&bounce_lock);
1200         }
1201         mtx_unlock(&bounce_lock);
1202 }