sys/platform/pc64/amd64/busdma_machdep.c

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