sys/platform/vkernel64/platform/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 struct bounce_zone;
  55 struct bus_dmamap;
  56
  57 struct bus_dma_tag {
  58         bus_dma_tag_t   parent;
  59         bus_size_t      alignment;
  60         bus_size_t      boundary;
  61         bus_addr_t      lowaddr;
  62         bus_addr_t      highaddr;
  63         bus_dma_filter_t *filter;
  64         void            *filterarg;
  65         bus_size_t      maxsize;
  66         u_int           nsegments;
  67         bus_size_t      maxsegsz;
  68         int             flags;
  69         int             ref_count;
  70         int             map_count;
  71         bus_dma_segment_t *segments;
  72         struct bounce_zone *bounce_zone;
  73 };
  74
  75 /*
  76  * bus_dma_tag private flags
  77  */
  78 #define BUS_DMA_BOUNCE_ALIGN    BUS_DMA_BUS2
  79 #define BUS_DMA_BOUNCE_LOWADDR  BUS_DMA_BUS3
  80 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  81
  82 #define BUS_DMA_COULD_BOUNCE    (BUS_DMA_BOUNCE_LOWADDR | BUS_DMA_BOUNCE_ALIGN)
  83
  84 #define BUS_DMAMEM_KMALLOC(dmat) \
  85         ((dmat)->maxsize <= PAGE_SIZE && \
  86          (dmat)->alignment <= PAGE_SIZE && \
  87          (dmat)->lowaddr >= ptoa(Maxmem))
  88
  89 struct bounce_page {
  90         vm_offset_t     vaddr;          /* kva of bounce buffer */
  91         bus_addr_t      busaddr;        /* Physical address */
  92         vm_offset_t     datavaddr;      /* kva of client data */
  93         bus_size_t      datacount;      /* client data count */
  94         STAILQ_ENTRY(bounce_page) links;
  95 };
  96
  97 struct bounce_zone {
  98         STAILQ_ENTRY(bounce_zone) links;
  99         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
 100         STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 101 #ifdef SMP
 102         struct spinlock spin;
 103 #else
 104         int             unused0;
 105 #endif
 106         int             total_bpages;
 107         int             free_bpages;
 108         int             reserved_bpages;
 109         int             active_bpages;
 110         int             total_bounced;
 111         int             total_deferred;
 112         int             reserve_failed;
 113         bus_size_t      alignment;
 114         bus_addr_t      lowaddr;
 115         char            zoneid[8];
 116         char            lowaddrid[20];
 117         struct sysctl_ctx_list sysctl_ctx;
 118         struct sysctl_oid *sysctl_tree;
 119 };
 120
 121 #ifdef SMP
 122 #define BZ_LOCK(bz)     spin_lock(&(bz)->spin)
 123 #define BZ_UNLOCK(bz)   spin_unlock(&(bz)->spin)
 124 #else
 125 #define BZ_LOCK(bz)     crit_enter()
 126 #define BZ_UNLOCK(bz)   crit_exit()
 127 #endif
 128
 129 static struct lwkt_token bounce_zone_tok =
 130         LWKT_TOKEN_INITIALIZER(bounce_zone_token);
 131 static int busdma_zonecount;
 132 static STAILQ_HEAD(, bounce_zone) bounce_zone_list =
 133         STAILQ_HEAD_INITIALIZER(bounce_zone_list);
 134
 135 int busdma_swi_pending;
 136 static int total_bounce_pages;
 137 static int max_bounce_pages = MAX_BPAGES;
 138 static int bounce_alignment = 1; /* XXX temporary */
 139
 140 TUNABLE_INT("hw.busdma.max_bpages", &max_bounce_pages);
 141 TUNABLE_INT("hw.busdma.bounce_alignment", &bounce_alignment);
 142
 143 struct bus_dmamap {
 144         struct bp_list  bpages;
 145         int             pagesneeded;
 146         int             pagesreserved;
 147         bus_dma_tag_t   dmat;
 148         void            *buf;           /* unmapped buffer pointer */
 149         bus_size_t      buflen;         /* unmapped buffer length */
 150         bus_dmamap_callback_t *callback;
 151         void            *callback_arg;
 152         STAILQ_ENTRY(bus_dmamap) links;
 153 };
 154
 155 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist =
 156         STAILQ_HEAD_INITIALIZER(bounce_map_callbacklist);
 157
 158 static struct bus_dmamap nobounce_dmamap;
 159
 160 static int              alloc_bounce_zone(bus_dma_tag_t);
 161 static int              alloc_bounce_pages(bus_dma_tag_t, u_int, int);
 162 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
 163 static void             return_bounce_pages(bus_dma_tag_t, bus_dmamap_t);
 164 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
 165                             vm_offset_t, bus_size_t);
 166 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
 167
 168 static bus_dmamap_t     get_map_waiting(bus_dma_tag_t);
 169 static void             add_map_callback(bus_dmamap_t);
 170
 171 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 172 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bounce_pages,
 173            0, "Total bounce pages");
 174 SYSCTL_INT(_hw_busdma, OID_AUTO, max_bpages, CTLFLAG_RD, &max_bounce_pages,
 175            0, "Max bounce pages per bounce zone");
 176 SYSCTL_INT(_hw_busdma, OID_AUTO, bounce_alignment, CTLFLAG_RD,
 177            &bounce_alignment, 0, "Obey alignment constraint");
 178
 179 static __inline int
 180 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 181 {
 182         int retval;
 183
 184         retval = 0;
 185         do {
 186                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr) ||
 187                      (bounce_alignment && (paddr & (dmat->alignment - 1)) != 0))
 188                  && (dmat->filter == NULL ||
 189                      dmat->filter(dmat->filterarg, paddr) != 0))
 190                         retval = 1;
 191
 192                 dmat = dmat->parent;
 193         } while (retval == 0 && dmat != NULL);
 194         return (retval);
 195 }
 196
 197 /*
 198  * Allocate a device specific dma_tag.
 199  */
 200 int
 201 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 202                    bus_size_t boundary, bus_addr_t lowaddr,
 203                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 204                    void *filterarg, bus_size_t maxsize, int nsegments,
 205                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 206 {
 207         bus_dma_tag_t newtag;
 208         int error = 0;
 209
 210         /*
 211          * Sanity checks
 212          */
 213
 214         if (alignment == 0)
 215                 alignment = 1;
 216         if (alignment & (alignment - 1))
 217                 panic("alignment must be power of 2\n");
 218
 219         if (boundary != 0) {
 220                 if (boundary & (boundary - 1))
 221                         panic("boundary must be power of 2\n");
 222                 if (boundary < maxsegsz) {
 223                         kprintf("boundary < maxsegsz:\n");
 224                         print_backtrace(-1);
 225                         maxsegsz = boundary;
 226                 }
 227         }
 228
 229         /* Return a NULL tag on failure */
 230         *dmat = NULL;
 231
 232         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT);
 233
 234         newtag->parent = parent;
 235         newtag->alignment = alignment;
 236         newtag->boundary = boundary;
 237         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 238         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 239         newtag->filter = filter;
 240         newtag->filterarg = filterarg;
 241         newtag->maxsize = maxsize;
 242         newtag->nsegments = nsegments;
 243         newtag->maxsegsz = maxsegsz;
 244         newtag->flags = flags;
 245         newtag->ref_count = 1; /* Count ourself */
 246         newtag->map_count = 0;
 247         newtag->segments = NULL;
 248         newtag->bounce_zone = NULL;
 249
 250         /* Take into account any restrictions imposed by our parent tag */
 251         if (parent != NULL) {
 252                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 253                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 254
 255                 if (newtag->boundary == 0) {
 256                         newtag->boundary = parent->boundary;
 257                 } else if (parent->boundary != 0) {
 258                         newtag->boundary = MIN(parent->boundary,
 259                                                newtag->boundary);
 260                 }
 261
 262 #ifdef notyet
 263                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
 264 #endif
 265
 266                 if (newtag->filter == NULL) {
 267                         /*
 268                          * Short circuit looking at our parent directly
 269                          * since we have encapsulated all of its information
 270                          */
 271                         newtag->filter = parent->filter;
 272                         newtag->filterarg = parent->filterarg;
 273                         newtag->parent = parent->parent;
 274                 }
 275                 if (newtag->parent != NULL)
 276                         parent->ref_count++;
 277         }
 278
 279         if (newtag->lowaddr < ptoa(Maxmem))
 280                 newtag->flags |= BUS_DMA_BOUNCE_LOWADDR;
 281         if (bounce_alignment && newtag->alignment > 1 &&
 282             !(newtag->flags & BUS_DMA_ALIGNED))
 283                 newtag->flags |= BUS_DMA_BOUNCE_ALIGN;
 284
 285         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
 286             (flags & BUS_DMA_ALLOCNOW) != 0) {
 287                 struct bounce_zone *bz;
 288
 289                 /* Must bounce */
 290
 291                 error = alloc_bounce_zone(newtag);
 292                 if (error)
 293                         goto back;
 294                 bz = newtag->bounce_zone;
 295
 296                 if (ptoa(bz->total_bpages) < maxsize) {
 297                         int pages;
 298
 299                         if (flags & BUS_DMA_ONEBPAGE) {
 300                                 pages = 1;
 301                         } else {
 302                                 pages = atop(round_page(maxsize)) -
 303                                         bz->total_bpages;
 304                                 pages = MAX(pages, 1);
 305                         }
 306
 307                         /* Add pages to our bounce pool */
 308                         if (alloc_bounce_pages(newtag, pages, flags) < pages)
 309                                 error = ENOMEM;
 310
 311                         /* Performed initial allocation */
 312                         newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 313                 }
 314         }
 315 back:
 316         if (error)
 317                 kfree(newtag, M_DEVBUF);
 318         else
 319                 *dmat = newtag;
 320         return error;
 321 }
 322
 323 int
 324 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 325 {
 326         if (dmat != NULL) {
 327                 if (dmat->map_count != 0)
 328                         return (EBUSY);
 329
 330                 while (dmat != NULL) {
 331                         bus_dma_tag_t parent;
 332
 333                         parent = dmat->parent;
 334                         dmat->ref_count--;
 335                         if (dmat->ref_count == 0) {
 336                                 if (dmat->segments != NULL)
 337                                         kfree(dmat->segments, M_DEVBUF);
 338                                 kfree(dmat, M_DEVBUF);
 339                                 /*
 340                                  * Last reference count, so
 341                                  * release our reference
 342                                  * count on our parent.
 343                                  */
 344                                 dmat = parent;
 345                         } else
 346                                 dmat = NULL;
 347                 }
 348         }
 349         return (0);
 350 }
 351
 352 /*
 353  * Allocate a handle for mapping from kva/uva/physical
 354  * address space into bus device space.
 355  */
 356 int
 357 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 358 {
 359         int error;
 360
 361         error = 0;
 362
 363         if (dmat->segments == NULL) {
 364                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 365                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 366                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 367         }
 368
 369         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 370                 struct bounce_zone *bz;
 371                 int maxpages;
 372
 373                 /* Must bounce */
 374
 375                 if (dmat->bounce_zone == NULL) {
 376                         error = alloc_bounce_zone(dmat);
 377                         if (error)
 378                                 return error;
 379                 }
 380                 bz = dmat->bounce_zone;
 381
 382                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
 383
 384                 /* Initialize the new map */
 385                 STAILQ_INIT(&((*mapp)->bpages));
 386
 387                 /*
 388                  * Attempt to add pages to our pool on a per-instance
 389                  * basis up to a sane limit.
 390                  */
 391                 if (dmat->flags & BUS_DMA_BOUNCE_ALIGN) {
 392                         maxpages = max_bounce_pages;
 393                 } else {
 394                         maxpages = MIN(max_bounce_pages,
 395                                        Maxmem - atop(dmat->lowaddr));
 396                 }
 397                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 398                  || (dmat->map_count > 0
 399                   && bz->total_bpages < maxpages)) {
 400                         int pages;
 401
 402                         if (flags & BUS_DMA_ONEBPAGE) {
 403                                 pages = 1;
 404                         } else {
 405                                 pages = atop(round_page(dmat->maxsize));
 406                                 pages = MIN(maxpages - bz->total_bpages, pages);
 407                                 pages = MAX(pages, 1);
 408                         }
 409                         if (alloc_bounce_pages(dmat, pages, flags) < pages)
 410                                 error = ENOMEM;
 411
 412                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 413                                 if (!error)
 414                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 415                         } else {
 416                                 error = 0;
 417                         }
 418                 }
 419         } else {
 420                 *mapp = NULL;
 421         }
 422         if (!error)
 423                 dmat->map_count++;
 424         return error;
 425 }
 426
 427 /*
 428  * Destroy a handle for mapping from kva/uva/physical
 429  * address space into bus device space.
 430  */
 431 int
 432 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 433 {
 434         if (map != NULL) {
 435                 if (STAILQ_FIRST(&map->bpages) != NULL)
 436                         return (EBUSY);
 437                 kfree(map, M_DEVBUF);
 438         }
 439         dmat->map_count--;
 440         return (0);
 441 }
 442
 443 static __inline bus_size_t
 444 check_kmalloc(bus_dma_tag_t dmat, const void *vaddr0, int verify)
 445 {
 446         bus_size_t maxsize = 0;
 447         uintptr_t vaddr = (uintptr_t)vaddr0;
 448
 449         if ((vaddr ^ (vaddr + dmat->maxsize - 1)) & ~PAGE_MASK) {
 450                 kprintf("boundary check failed\n");
 451                 if (verify)
 452                         print_backtrace(-1); /* XXX panic */
 453                 maxsize = dmat->maxsize;
 454         }
 455         if (vaddr & (dmat->alignment - 1)) {
 456                 kprintf("alignment check failed\n");
 457                 if (verify)
 458                         print_backtrace(-1); /* XXX panic */
 459                 if (dmat->maxsize < dmat->alignment)
 460                         maxsize = dmat->alignment;
 461                 else
 462                         maxsize = dmat->maxsize;
 463         }
 464         return maxsize;
 465 }
 466
 467 /*
 468  * Allocate a piece of memory that can be efficiently mapped into
 469  * bus device space based on the constraints lited in the dma tag.
 470  *
 471  * mapp is degenerate.  By definition this allocation should not require
 472  * bounce buffers so do not allocate a dma map.
 473  */
 474 int
 475 bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr, int flags,
 476                  bus_dmamap_t *mapp)
 477 {
 478         int mflags;
 479
 480         /* If we succeed, no mapping/bouncing will be required */
 481         *mapp = NULL;
 482
 483         if (dmat->segments == NULL) {
 484                 KKASSERT(dmat->nsegments < 16384);
 485                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 486                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 487         }
 488
 489         if (flags & BUS_DMA_NOWAIT)
 490                 mflags = M_NOWAIT;
 491         else
 492                 mflags = M_WAITOK;
 493         if (flags & BUS_DMA_ZERO)
 494                 mflags |= M_ZERO;
 495
 496         if (BUS_DMAMEM_KMALLOC(dmat)) {
 497                 bus_size_t maxsize;
 498
 499                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 500
 501                 /*
 502                  * XXX
 503                  * Check whether the allocation
 504                  * - crossed a page boundary
 505                  * - was not aligned
 506                  * Retry with power-of-2 alignment in the above cases.
 507                  */
 508                 maxsize = check_kmalloc(dmat, *vaddr, 0);
 509                 if (maxsize) {
 510                         size_t size;
 511
 512                         kfree(*vaddr, M_DEVBUF);
 513                         /* XXX check for overflow? */
 514                         for (size = 1; size <= maxsize; size <<= 1)
 515                                 ;
 516                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 517                         check_kmalloc(dmat, *vaddr, 1);
 518                 }
 519         } else {
 520                 /*
 521                  * XXX Use Contigmalloc until it is merged into this facility
 522                  *     and handles multi-seg allocations.  Nobody is doing
 523                  *     multi-seg allocations yet though.
 524                  */
 525                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 526                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
 527         }
 528         if (*vaddr == NULL)
 529                 return (ENOMEM);
 530         return (0);
 531 }
 532
 533 /*
 534  * Free a piece of memory and it's allociated dmamap, that was allocated
 535  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 536  */
 537 void
 538 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 539 {
 540         /*
 541          * dmamem does not need to be bounced, so the map should be
 542          * NULL
 543          */
 544         if (map != NULL)
 545                 panic("bus_dmamem_free: Invalid map freed\n");
 546         if (BUS_DMAMEM_KMALLOC(dmat))
 547                 kfree(vaddr, M_DEVBUF);
 548         else
 549                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 550 }
 551
 552 static __inline vm_paddr_t
 553 _bus_dma_extract(pmap_t pmap, vm_offset_t vaddr)
 554 {
 555         if (pmap)
 556                 return pmap_extract(pmap, vaddr);
 557         else
 558                 return pmap_kextract(vaddr);
 559 }
 560
 561 /*
 562  * Utility function to load a linear buffer.  lastaddrp holds state
 563  * between invocations (for multiple-buffer loads).  segp contains
 564  * the segment following the starting one on entrace, and the ending
 565  * segment on exit.  first indicates if this is the first invocation
 566  * of this function.
 567  */
 568 static int
 569 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 570                         bus_dmamap_t map,
 571                         void *buf, bus_size_t buflen,
 572                         bus_dma_segment_t *segments,
 573                         int nsegments,
 574                         pmap_t pmap,
 575                         int flags,
 576                         vm_paddr_t *lastpaddrp,
 577                         int *segp,
 578                         int first)
 579 {
 580         vm_offset_t vaddr;
 581         vm_paddr_t paddr, nextpaddr;
 582         bus_dma_segment_t *sg;
 583         bus_addr_t bmask;
 584         int seg, error = 0;
 585
 586         if (map == NULL)
 587                 map = &nobounce_dmamap;
 588
 589 #ifdef INVARIANTS
 590         if (dmat->flags & BUS_DMA_ALIGNED)
 591                 KKASSERT(((uintptr_t)buf & (dmat->alignment - 1)) == 0);
 592 #endif
 593
 594         /*
 595          * If we are being called during a callback, pagesneeded will
 596          * be non-zero, so we can avoid doing the work twice.
 597          */
 598         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 599             map != &nobounce_dmamap && map->pagesneeded == 0) {
 600                 vm_offset_t vendaddr;
 601
 602                 /*
 603                  * Count the number of bounce pages
 604                  * needed in order to complete this transfer
 605                  */
 606                 vaddr = (vm_offset_t)buf;
 607                 vendaddr = (vm_offset_t)buf + buflen;
 608
 609                 while (vaddr < vendaddr) {
 610                         paddr = _bus_dma_extract(pmap, vaddr);
 611                         if (run_filter(dmat, paddr) != 0)
 612                                 map->pagesneeded++;
 613                         vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
 614                 }
 615         }
 616
 617         /* Reserve Necessary Bounce Pages */
 618         if (map->pagesneeded != 0) {
 619                 struct bounce_zone *bz;
 620
 621                 bz = dmat->bounce_zone;
 622                 BZ_LOCK(bz);
 623                 if (flags & BUS_DMA_NOWAIT) {
 624                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
 625                                 BZ_UNLOCK(bz);
 626                                 error = ENOMEM;
 627                                 goto free_bounce;
 628                         }
 629                 } else {
 630                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
 631                                 /* Queue us for resources */
 632                                 map->dmat = dmat;
 633                                 map->buf = buf;
 634                                 map->buflen = buflen;
 635
 636                                 STAILQ_INSERT_TAIL(
 637                                     &dmat->bounce_zone->bounce_map_waitinglist,
 638                                     map, links);
 639                                 BZ_UNLOCK(bz);
 640
 641                                 return (EINPROGRESS);
 642                         }
 643                 }
 644                 BZ_UNLOCK(bz);
 645         }
 646
 647         KKASSERT(*segp >= 1 && *segp <= nsegments);
 648         seg = *segp;
 649         sg = &segments[seg - 1];
 650
 651         vaddr = (vm_offset_t)buf;
 652         nextpaddr = *lastpaddrp;
 653         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 654
 655         /* force at least one segment */
 656         do {
 657                 bus_size_t size;
 658
 659                 /*
 660                  * Per-page main loop
 661                  */
 662                 paddr = _bus_dma_extract(pmap, vaddr);
 663                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 664                 if (size > buflen)
 665                         size = buflen;
 666                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 667                         /*
 668                          * note: this paddr has the same in-page offset
 669                          * as vaddr and thus the paddr above, so the
 670                          * size does not have to be recalculated
 671                          */
 672                         paddr = add_bounce_page(dmat, map, vaddr, size);
 673                 }
 674
 675                 /*
 676                  * Fill in the bus_dma_segment
 677                  */
 678                 if (first) {
 679                         sg->ds_addr = paddr;
 680                         sg->ds_len = size;
 681                         first = 0;
 682                 } else if (paddr == nextpaddr) {
 683                         sg->ds_len += size;
 684                 } else {
 685                         sg++;
 686                         seg++;
 687                         if (seg > nsegments)
 688                                 break;
 689                         sg->ds_addr = paddr;
 690                         sg->ds_len = size;
 691                 }
 692                 nextpaddr = paddr + size;
 693
 694                 /*
 695                  * Handle maxsegsz and boundary issues with a nested loop
 696                  */
 697                 for (;;) {
 698                         bus_size_t tmpsize;
 699
 700                         /*
 701                          * Limit to the boundary and maximum segment size
 702                          */
 703                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 704                                 tmpsize = dmat->boundary -
 705                                           (sg->ds_addr & ~bmask);
 706                                 if (tmpsize > dmat->maxsegsz)
 707                                         tmpsize = dmat->maxsegsz;
 708                                 KKASSERT(tmpsize < sg->ds_len);
 709                         } else if (sg->ds_len > dmat->maxsegsz) {
 710                                 tmpsize = dmat->maxsegsz;
 711                         } else {
 712                                 break;
 713                         }
 714
 715                         /*
 716                          * Futz, split the data into a new segment.
 717                          */
 718                         if (seg >= nsegments)
 719                                 goto fail;
 720                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 721                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 722                         sg[0].ds_len = tmpsize;
 723                         sg++;
 724                         seg++;
 725                 }
 726
 727                 /*
 728                  * Adjust for loop
 729                  */
 730                 buflen -= size;
 731                 vaddr += size;
 732         } while (buflen > 0);
 733 fail:
 734         if (buflen != 0)
 735                 error = EFBIG;
 736
 737         *segp = seg;
 738         *lastpaddrp = nextpaddr;
 739
 740 free_bounce:
 741         if (error && (dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 742             map != &nobounce_dmamap) {
 743                 _bus_dmamap_unload(dmat, map);
 744                 return_bounce_pages(dmat, map);
 745         }
 746         return error;
 747 }
 748
 749 /*
 750  * Map the buffer buf into bus space using the dmamap map.
 751  */
 752 int
 753 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 754                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 755                 void *callback_arg, int flags)
 756 {
 757         vm_paddr_t lastaddr = 0;
 758         int error, nsegs = 1;
 759
 760         if (map != NULL) {
 761                 /*
 762                  * XXX
 763                  * Follow old semantics.  Once all of the callers are fixed,
 764                  * we should get rid of these internal flag "adjustment".
 765                  */
 766                 flags &= ~BUS_DMA_NOWAIT;
 767                 flags |= BUS_DMA_WAITOK;
 768
 769                 map->callback = callback;
 770                 map->callback_arg = callback_arg;
 771         }
 772
 773         error = _bus_dmamap_load_buffer(dmat, map, buf, buflen,
 774                         dmat->segments, dmat->nsegments,
 775                         NULL, flags, &lastaddr, &nsegs, 1);
 776         if (error == EINPROGRESS)
 777                 return error;
 778
 779         callback(callback_arg, dmat->segments, nsegs, error);
 780         return 0;
 781 }
 782
 783 /*
 784  * Like _bus_dmamap_load(), but for mbufs.
 785  */
 786 int
 787 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 788                      struct mbuf *m0,
 789                      bus_dmamap_callback2_t *callback, void *callback_arg,
 790                      int flags)
 791 {
 792         int nsegs, error;
 793
 794         /*
 795          * XXX
 796          * Follow old semantics.  Once all of the callers are fixed,
 797          * we should get rid of these internal flag "adjustment".
 798          */
 799         flags &= ~BUS_DMA_WAITOK;
 800         flags |= BUS_DMA_NOWAIT;
 801
 802         error = bus_dmamap_load_mbuf_segment(dmat, map, m0,
 803                         dmat->segments, dmat->nsegments, &nsegs, flags);
 804         if (error) {
 805                 /* force "no valid mappings" in callback */
 806                 callback(callback_arg, dmat->segments, 0, 0, error);
 807         } else {
 808                 callback(callback_arg, dmat->segments, nsegs,
 809                          m0->m_pkthdr.len, error);
 810         }
 811         return error;
 812 }
 813
 814 int
 815 bus_dmamap_load_mbuf_segment(bus_dma_tag_t dmat, bus_dmamap_t map,
 816                              struct mbuf *m0,
 817                              bus_dma_segment_t *segs, int maxsegs,
 818                              int *nsegs, int flags)
 819 {
 820         int error;
 821
 822         M_ASSERTPKTHDR(m0);
 823
 824         KASSERT(maxsegs >= 1, ("invalid maxsegs %d\n", maxsegs));
 825         KASSERT(maxsegs <= dmat->nsegments,
 826                 ("%d too many segments, dmat only support %d segments\n",
 827                  maxsegs, dmat->nsegments));
 828         KASSERT(flags & BUS_DMA_NOWAIT,
 829                 ("only BUS_DMA_NOWAIT is supported\n"));
 830
 831         if (m0->m_pkthdr.len <= dmat->maxsize) {
 832                 int first = 1;
 833                 vm_paddr_t lastaddr = 0;
 834                 struct mbuf *m;
 835
 836                 *nsegs = 1;
 837                 error = 0;
 838                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 839                         if (m->m_len == 0)
 840                                 continue;
 841
 842                         error = _bus_dmamap_load_buffer(dmat, map,
 843                                         m->m_data, m->m_len,
 844                                         segs, maxsegs,
 845                                         NULL, flags, &lastaddr,
 846                                         nsegs, first);
 847                         if (error == ENOMEM && !first) {
 848                                 /*
 849                                  * Out of bounce pages due to too many
 850                                  * fragments in the mbuf chain; return
 851                                  * EFBIG instead.
 852                                  */
 853                                 error = EFBIG;
 854                         }
 855                         first = 0;
 856                 }
 857 #ifdef INVARIANTS
 858                 if (!error)
 859                         KKASSERT(*nsegs <= maxsegs && *nsegs >= 1);
 860 #endif
 861         } else {
 862                 *nsegs = 0;
 863                 error = EINVAL;
 864         }
 865         KKASSERT(error != EINPROGRESS);
 866         return error;
 867 }
 868
 869 /*
 870  * Like _bus_dmamap_load(), but for uios.
 871  */
 872 int
 873 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 874                     struct uio *uio,
 875                     bus_dmamap_callback2_t *callback, void *callback_arg,
 876                     int flags)
 877 {
 878         vm_paddr_t lastaddr;
 879         int nsegs, error, first, i;
 880         bus_size_t resid;
 881         struct iovec *iov;
 882         pmap_t pmap;
 883
 884         /*
 885          * XXX
 886          * Follow old semantics.  Once all of the callers are fixed,
 887          * we should get rid of these internal flag "adjustment".
 888          */
 889         flags &= ~BUS_DMA_WAITOK;
 890         flags |= BUS_DMA_NOWAIT;
 891
 892         resid = (bus_size_t)uio->uio_resid;
 893         iov = uio->uio_iov;
 894
 895         if (uio->uio_segflg == UIO_USERSPACE) {
 896                 struct thread *td;
 897
 898                 td = uio->uio_td;
 899                 KASSERT(td != NULL && td->td_proc != NULL,
 900                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 901                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 902         } else {
 903                 pmap = NULL;
 904         }
 905
 906         error = 0;
 907         nsegs = 1;
 908         first = 1;
 909         lastaddr = 0;
 910         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 911                 /*
 912                  * Now at the first iovec to load.  Load each iovec
 913                  * until we have exhausted the residual count.
 914                  */
 915                 bus_size_t minlen =
 916                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 917                 caddr_t addr = (caddr_t) iov[i].iov_base;
 918
 919                 error = _bus_dmamap_load_buffer(dmat, map, addr, minlen,
 920                                 dmat->segments, dmat->nsegments,
 921                                 pmap, flags, &lastaddr, &nsegs, first);
 922                 first = 0;
 923
 924                 resid -= minlen;
 925         }
 926
 927         if (error) {
 928                 /* force "no valid mappings" in callback */
 929                 callback(callback_arg, dmat->segments, 0, 0, error);
 930         } else {
 931                 callback(callback_arg, dmat->segments, nsegs,
 932                          (bus_size_t)uio->uio_resid, error);
 933         }
 934         return error;
 935 }
 936
 937 /*
 938  * Release the mapping held by map.
 939  */
 940 void
 941 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 942 {
 943         struct bounce_page *bpage;
 944
 945         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 946                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 947                 free_bounce_page(dmat, bpage);
 948         }
 949 }
 950
 951 void
 952 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 953 {
 954         struct bounce_page *bpage;
 955
 956         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 957                 /*
 958                  * Handle data bouncing.  We might also
 959                  * want to add support for invalidating
 960                  * the caches on broken hardware
 961                  */
 962                 switch (op) {
 963                 case BUS_DMASYNC_PREWRITE:
 964                         while (bpage != NULL) {
 965                                 bcopy((void *)bpage->datavaddr,
 966                                       (void *)bpage->vaddr,
 967                                       bpage->datacount);
 968                                 bpage = STAILQ_NEXT(bpage, links);
 969                         }
 970                         dmat->bounce_zone->total_bounced++;
 971                         break;
 972
 973                 case BUS_DMASYNC_POSTREAD:
 974                         while (bpage != NULL) {
 975                                 bcopy((void *)bpage->vaddr,
 976                                       (void *)bpage->datavaddr,
 977                                       bpage->datacount);
 978                                 bpage = STAILQ_NEXT(bpage, links);
 979                         }
 980                         dmat->bounce_zone->total_bounced++;
 981                         break;
 982
 983                 case BUS_DMASYNC_PREREAD:
 984                 case BUS_DMASYNC_POSTWRITE:
 985                         /* No-ops */
 986                         break;
 987                 }
 988         }
 989 }
 990
 991 static int
 992 alloc_bounce_zone(bus_dma_tag_t dmat)
 993 {
 994         struct bounce_zone *bz, *new_bz;
 995
 996         KASSERT(dmat->bounce_zone == NULL,
 997                 ("bounce zone was already assigned\n"));
 998
 999         new_bz = kmalloc(sizeof(*new_bz), M_DEVBUF, M_INTWAIT | M_ZERO);
1000
1001         lwkt_gettoken(&bounce_zone_tok);
1002
1003         /* Check to see if we already have a suitable zone */
1004         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1005                 if (dmat->alignment <= bz->alignment &&
1006                     dmat->lowaddr >= bz->lowaddr) {
1007                         lwkt_reltoken(&bounce_zone_tok);
1008
1009                         dmat->bounce_zone = bz;
1010                         kfree(new_bz, M_DEVBUF);
1011                         return 0;
1012                 }
1013         }
1014         bz = new_bz;
1015
1016 #ifdef SMP
1017         spin_init(&bz->spin);
1018 #endif
1019         STAILQ_INIT(&bz->bounce_page_list);
1020         STAILQ_INIT(&bz->bounce_map_waitinglist);
1021         bz->free_bpages = 0;
1022         bz->reserved_bpages = 0;
1023         bz->active_bpages = 0;
1024         bz->lowaddr = dmat->lowaddr;
1025         bz->alignment = round_page(dmat->alignment);
1026         ksnprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1027         busdma_zonecount++;
1028         ksnprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1029         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1030
1031         lwkt_reltoken(&bounce_zone_tok);
1032
1033         dmat->bounce_zone = bz;
1034
1035         sysctl_ctx_init(&bz->sysctl_ctx);
1036         bz->sysctl_tree = SYSCTL_ADD_NODE(&bz->sysctl_ctx,
1037             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1038             CTLFLAG_RD, 0, "");
1039         if (bz->sysctl_tree == NULL) {
1040                 sysctl_ctx_free(&bz->sysctl_ctx);
1041                 return 0;       /* XXX error code? */
1042         }
1043
1044         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1045             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1046             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1047             "Total bounce pages");
1048         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1049             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1050             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1051             "Free bounce pages");
1052         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1053             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1054             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1055             "Reserved bounce pages");
1056         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1057             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1058             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1059             "Active bounce pages");
1060         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1061             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1062             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1063             "Total bounce requests");
1064         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1065             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1066             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1067             "Total bounce requests that were deferred");
1068         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1069             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1070             "reserve_failed", CTLFLAG_RD, &bz->reserve_failed, 0,
1071             "Total bounce page reservations that were failed");
1072         SYSCTL_ADD_STRING(&bz->sysctl_ctx,
1073             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1074             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1075         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1076             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1077             "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
1078
1079         return 0;
1080 }
1081
1082 static int
1083 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages, int flags)
1084 {
1085         struct bounce_zone *bz = dmat->bounce_zone;
1086         int count = 0, mflags;
1087
1088         if (flags & BUS_DMA_NOWAIT)
1089                 mflags = M_NOWAIT;
1090         else
1091                 mflags = M_WAITOK;
1092
1093         while (numpages > 0) {
1094                 struct bounce_page *bpage;
1095
1096                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
1097
1098                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1099                                                          mflags, 0ul,
1100                                                          bz->lowaddr,
1101                                                          bz->alignment, 0);
1102                 if (bpage->vaddr == 0) {
1103                         kfree(bpage, M_DEVBUF);
1104                         break;
1105                 }
1106                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1107
1108                 BZ_LOCK(bz);
1109                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1110                 total_bounce_pages++;
1111                 bz->total_bpages++;
1112                 bz->free_bpages++;
1113                 BZ_UNLOCK(bz);
1114
1115                 count++;
1116                 numpages--;
1117         }
1118         return count;
1119 }
1120
1121 /* Assume caller holds bounce zone spinlock */
1122 static int
1123 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1124 {
1125         struct bounce_zone *bz = dmat->bounce_zone;
1126         int pages;
1127
1128         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1129         if (!commit && map->pagesneeded > (map->pagesreserved + pages)) {
1130                 bz->reserve_failed++;
1131                 return (map->pagesneeded - (map->pagesreserved + pages));
1132         }
1133
1134         bz->free_bpages -= pages;
1135
1136         bz->reserved_bpages += pages;
1137         KKASSERT(bz->reserved_bpages <= bz->total_bpages);
1138
1139         map->pagesreserved += pages;
1140         pages = map->pagesneeded - map->pagesreserved;
1141
1142         return pages;
1143 }
1144
1145 static void
1146 return_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
1147 {
1148         struct bounce_zone *bz = dmat->bounce_zone;
1149         int reserved = map->pagesreserved;
1150         bus_dmamap_t wait_map;
1151
1152         map->pagesreserved = 0;
1153         map->pagesneeded = 0;
1154
1155         if (reserved == 0)
1156                 return;
1157
1158         BZ_LOCK(bz);
1159
1160         bz->free_bpages += reserved;
1161         KKASSERT(bz->free_bpages <= bz->total_bpages);
1162
1163         KKASSERT(bz->reserved_bpages >= reserved);
1164         bz->reserved_bpages -= reserved;
1165
1166         wait_map = get_map_waiting(dmat);
1167
1168         BZ_UNLOCK(bz);
1169
1170         if (wait_map != NULL)
1171                 add_map_callback(map);
1172 }
1173
1174 static bus_addr_t
1175 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1176                 bus_size_t size)
1177 {
1178         struct bounce_zone *bz = dmat->bounce_zone;
1179         struct bounce_page *bpage;
1180
1181         KASSERT(map->pagesneeded > 0, ("map doesn't need any pages"));
1182         map->pagesneeded--;
1183
1184         KASSERT(map->pagesreserved > 0, ("map doesn't reserve any pages"));
1185         map->pagesreserved--;
1186
1187         BZ_LOCK(bz);
1188
1189         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1190         KASSERT(bpage != NULL, ("free page list is empty"));
1191         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1192
1193         KKASSERT(bz->reserved_bpages > 0);
1194         bz->reserved_bpages--;
1195
1196         bz->active_bpages++;
1197         KKASSERT(bz->active_bpages <= bz->total_bpages);
1198
1199         BZ_UNLOCK(bz);
1200
1201         bpage->datavaddr = vaddr;
1202         bpage->datacount = size;
1203         STAILQ_INSERT_TAIL(&map->bpages, bpage, links);
1204         return bpage->busaddr;
1205 }
1206
1207 static void
1208 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1209 {
1210         struct bounce_zone *bz = dmat->bounce_zone;
1211         bus_dmamap_t map;
1212
1213         bpage->datavaddr = 0;
1214         bpage->datacount = 0;
1215
1216         BZ_LOCK(bz);
1217
1218         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1219
1220         bz->free_bpages++;
1221         KKASSERT(bz->free_bpages <= bz->total_bpages);
1222
1223         KKASSERT(bz->active_bpages > 0);
1224         bz->active_bpages--;
1225
1226         map = get_map_waiting(dmat);
1227
1228         BZ_UNLOCK(bz);
1229
1230         if (map != NULL)
1231                 add_map_callback(map);
1232 }
1233
1234 /* Assume caller holds bounce zone spinlock */
1235 static bus_dmamap_t
1236 get_map_waiting(bus_dma_tag_t dmat)
1237 {
1238         struct bounce_zone *bz = dmat->bounce_zone;
1239         bus_dmamap_t map;
1240
1241         map = STAILQ_FIRST(&bz->bounce_map_waitinglist);
1242         if (map != NULL) {
1243                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1244                         STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
1245                         bz->total_deferred++;
1246                 } else {
1247                         map = NULL;
1248                 }
1249         }
1250         return map;
1251 }
1252
1253 static void
1254 add_map_callback(bus_dmamap_t map)
1255 {
1256 #ifdef notyet
1257         /* XXX callbacklist is not MPSAFE */
1258         crit_enter();
1259         get_mplock();
1260         STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
1261         busdma_swi_pending = 1;
1262         setsoftvm();
1263         rel_mplock();
1264         crit_exit();
1265 #else
1266         panic("%s uncoded\n", __func__);
1267 #endif
1268 }
1269
1270 #ifdef notyet
1271 void
1272 busdma_swi(void)
1273 {
1274         bus_dmamap_t map;
1275
1276         crit_enter();
1277         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1278                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1279                 crit_exit();
1280                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
1281                                 map->callback, map->callback_arg, /*flags*/0);
1282                 crit_enter();
1283         }
1284         crit_exit();
1285 }
1286 #endif