sys/platform/vkernel/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  */
  28
  29 #include <sys/param.h>
  30 #include <sys/systm.h>
  31 #include <sys/malloc.h>
  32 #include <sys/mbuf.h>
  33 #include <sys/uio.h>
  34 #include <sys/bus_dma.h>
  35 #include <sys/kernel.h>
  36 #include <sys/sysctl.h>
  37 #include <sys/lock.h>
  38
  39 #include <sys/thread2.h>
  40 #include <sys/spinlock2.h>
  41 #include <sys/mplock2.h>
  42
  43 #include <vm/vm.h>
  44 #include <vm/vm_page.h>
  45
  46 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  47 #include <sys/proc.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         struct spinlock spin;
 102         int             total_bpages;
 103         int             free_bpages;
 104         int             reserved_bpages;
 105         int             active_bpages;
 106         int             total_bounced;
 107         int             total_deferred;
 108         int             reserve_failed;
 109         bus_size_t      alignment;
 110         bus_addr_t      lowaddr;
 111         char            zoneid[8];
 112         char            lowaddrid[20];
 113         struct sysctl_ctx_list sysctl_ctx;
 114         struct sysctl_oid *sysctl_tree;
 115 };
 116
 117 #define BZ_LOCK(bz)     spin_lock(&(bz)->spin)
 118 #define BZ_UNLOCK(bz)   spin_unlock(&(bz)->spin)
 119
 120 static struct lwkt_token bounce_zone_tok =
 121         LWKT_TOKEN_INITIALIZER(bounce_zone_token);
 122 static int busdma_zonecount;
 123 static STAILQ_HEAD(, bounce_zone) bounce_zone_list =
 124         STAILQ_HEAD_INITIALIZER(bounce_zone_list);
 125
 126 int busdma_swi_pending;
 127 static int total_bounce_pages;
 128 static int max_bounce_pages = MAX_BPAGES;
 129 static int bounce_alignment = 1; /* XXX temporary */
 130
 131 TUNABLE_INT("hw.busdma.max_bpages", &max_bounce_pages);
 132 TUNABLE_INT("hw.busdma.bounce_alignment", &bounce_alignment);
 133
 134 struct bus_dmamap {
 135         struct bp_list  bpages;
 136         int             pagesneeded;
 137         int             pagesreserved;
 138         bus_dma_tag_t   dmat;
 139         void            *buf;           /* unmapped buffer pointer */
 140         bus_size_t      buflen;         /* unmapped buffer length */
 141         bus_dmamap_callback_t *callback;
 142         void            *callback_arg;
 143         STAILQ_ENTRY(bus_dmamap) links;
 144 };
 145
 146 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist =
 147         STAILQ_HEAD_INITIALIZER(bounce_map_callbacklist);
 148
 149 static struct bus_dmamap nobounce_dmamap;
 150
 151 static int              alloc_bounce_zone(bus_dma_tag_t);
 152 static int              alloc_bounce_pages(bus_dma_tag_t, u_int, int);
 153 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
 154 static void             return_bounce_pages(bus_dma_tag_t, bus_dmamap_t);
 155 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
 156                             vm_offset_t, bus_size_t);
 157 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
 158
 159 static bus_dmamap_t     get_map_waiting(bus_dma_tag_t);
 160 static void             add_map_callback(bus_dmamap_t);
 161
 162 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 163 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bounce_pages,
 164            0, "Total bounce pages");
 165 SYSCTL_INT(_hw_busdma, OID_AUTO, max_bpages, CTLFLAG_RD, &max_bounce_pages,
 166            0, "Max bounce pages per bounce zone");
 167 SYSCTL_INT(_hw_busdma, OID_AUTO, bounce_alignment, CTLFLAG_RD,
 168            &bounce_alignment, 0, "Obey alignment constraint");
 169
 170 static __inline int
 171 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 172 {
 173         int retval;
 174
 175         retval = 0;
 176         do {
 177                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr) ||
 178                      (bounce_alignment && (paddr & (dmat->alignment - 1)) != 0))
 179                  && (dmat->filter == NULL ||
 180                      dmat->filter(dmat->filterarg, paddr) != 0))
 181                         retval = 1;
 182
 183                 dmat = dmat->parent;
 184         } while (retval == 0 && dmat != NULL);
 185         return (retval);
 186 }
 187
 188 /*
 189  * Allocate a device specific dma_tag.
 190  */
 191 int
 192 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 193                    bus_size_t boundary, bus_addr_t lowaddr,
 194                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 195                    void *filterarg, bus_size_t maxsize, int nsegments,
 196                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 197 {
 198         bus_dma_tag_t newtag;
 199         int error = 0;
 200
 201         /*
 202          * Sanity checks
 203          */
 204
 205         if (alignment == 0)
 206                 alignment = 1;
 207         if (alignment & (alignment - 1))
 208                 panic("alignment must be power of 2");
 209
 210         if (boundary != 0) {
 211                 if (boundary & (boundary - 1))
 212                         panic("boundary must be power of 2");
 213                 if (boundary < maxsegsz) {
 214                         kprintf("boundary < maxsegsz:\n");
 215                         print_backtrace(-1);
 216                         maxsegsz = boundary;
 217                 }
 218         }
 219
 220         /* Return a NULL tag on failure */
 221         *dmat = NULL;
 222
 223         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT);
 224
 225         newtag->parent = parent;
 226         newtag->alignment = alignment;
 227         newtag->boundary = boundary;
 228         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 229         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 230         newtag->filter = filter;
 231         newtag->filterarg = filterarg;
 232         newtag->maxsize = maxsize;
 233         newtag->nsegments = nsegments;
 234         newtag->maxsegsz = maxsegsz;
 235         newtag->flags = flags;
 236         newtag->ref_count = 1; /* Count ourself */
 237         newtag->map_count = 0;
 238         newtag->segments = NULL;
 239         newtag->bounce_zone = NULL;
 240
 241         /* Take into account any restrictions imposed by our parent tag */
 242         if (parent != NULL) {
 243                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 244                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 245
 246                 if (newtag->boundary == 0) {
 247                         newtag->boundary = parent->boundary;
 248                 } else if (parent->boundary != 0) {
 249                         newtag->boundary = MIN(parent->boundary,
 250                                                newtag->boundary);
 251                 }
 252
 253 #ifdef notyet
 254                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
 255 #endif
 256
 257                 if (newtag->filter == NULL) {
 258                         /*
 259                          * Short circuit looking at our parent directly
 260                          * since we have encapsulated all of its information
 261                          */
 262                         newtag->filter = parent->filter;
 263                         newtag->filterarg = parent->filterarg;
 264                         newtag->parent = parent->parent;
 265                 }
 266                 if (newtag->parent != NULL)
 267                         parent->ref_count++;
 268         }
 269
 270         if (newtag->lowaddr < ptoa(Maxmem))
 271                 newtag->flags |= BUS_DMA_BOUNCE_LOWADDR;
 272         if (bounce_alignment && newtag->alignment > 1 &&
 273             !(newtag->flags & BUS_DMA_ALIGNED))
 274                 newtag->flags |= BUS_DMA_BOUNCE_ALIGN;
 275
 276         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
 277             (flags & BUS_DMA_ALLOCNOW) != 0) {
 278                 struct bounce_zone *bz;
 279
 280                 /* Must bounce */
 281
 282                 error = alloc_bounce_zone(newtag);
 283                 if (error)
 284                         goto back;
 285                 bz = newtag->bounce_zone;
 286
 287                 if (ptoa(bz->total_bpages) < maxsize) {
 288                         int pages;
 289
 290                         if (flags & BUS_DMA_ONEBPAGE) {
 291                                 pages = 1;
 292                         } else {
 293                                 pages = atop(round_page(maxsize)) -
 294                                         bz->total_bpages;
 295                                 pages = MAX(pages, 1);
 296                         }
 297
 298                         /* Add pages to our bounce pool */
 299                         if (alloc_bounce_pages(newtag, pages, flags) < pages)
 300                                 error = ENOMEM;
 301
 302                         /* Performed initial allocation */
 303                         newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 304                 }
 305         }
 306 back:
 307         if (error)
 308                 kfree(newtag, M_DEVBUF);
 309         else
 310                 *dmat = newtag;
 311         return error;
 312 }
 313
 314 int
 315 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 316 {
 317         if (dmat != NULL) {
 318                 if (dmat->map_count != 0)
 319                         return (EBUSY);
 320
 321                 while (dmat != NULL) {
 322                         bus_dma_tag_t parent;
 323
 324                         parent = dmat->parent;
 325                         dmat->ref_count--;
 326                         if (dmat->ref_count == 0) {
 327                                 if (dmat->segments != NULL)
 328                                         kfree(dmat->segments, M_DEVBUF);
 329                                 kfree(dmat, M_DEVBUF);
 330                                 /*
 331                                  * Last reference count, so
 332                                  * release our reference
 333                                  * count on our parent.
 334                                  */
 335                                 dmat = parent;
 336                         } else
 337                                 dmat = NULL;
 338                 }
 339         }
 340         return (0);
 341 }
 342
 343 /*
 344  * Allocate a handle for mapping from kva/uva/physical
 345  * address space into bus device space.
 346  */
 347 int
 348 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 349 {
 350         int error;
 351
 352         error = 0;
 353
 354         if (dmat->segments == NULL) {
 355                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 356                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 357                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 358         }
 359
 360         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 361                 struct bounce_zone *bz;
 362                 int maxpages;
 363
 364                 /* Must bounce */
 365
 366                 if (dmat->bounce_zone == NULL) {
 367                         error = alloc_bounce_zone(dmat);
 368                         if (error)
 369                                 return error;
 370                 }
 371                 bz = dmat->bounce_zone;
 372
 373                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
 374
 375                 /* Initialize the new map */
 376                 STAILQ_INIT(&((*mapp)->bpages));
 377
 378                 /*
 379                  * Attempt to add pages to our pool on a per-instance
 380                  * basis up to a sane limit.
 381                  */
 382                 if (dmat->flags & BUS_DMA_BOUNCE_ALIGN) {
 383                         maxpages = max_bounce_pages;
 384                 } else {
 385                         maxpages = MIN(max_bounce_pages,
 386                                        Maxmem - atop(dmat->lowaddr));
 387                 }
 388                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 389                  || (dmat->map_count > 0
 390                   && bz->total_bpages < maxpages)) {
 391                         int pages;
 392
 393                         if (flags & BUS_DMA_ONEBPAGE) {
 394                                 pages = 1;
 395                         } else {
 396                                 pages = atop(round_page(dmat->maxsize));
 397                                 pages = MIN(maxpages - bz->total_bpages, pages);
 398                                 pages = MAX(pages, 1);
 399                         }
 400                         if (alloc_bounce_pages(dmat, pages, flags) < pages)
 401                                 error = ENOMEM;
 402
 403                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 404                                 if (!error)
 405                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 406                         } else {
 407                                 error = 0;
 408                         }
 409                 }
 410         } else {
 411                 *mapp = NULL;
 412         }
 413         if (!error)
 414                 dmat->map_count++;
 415         return error;
 416 }
 417
 418 /*
 419  * Destroy a handle for mapping from kva/uva/physical
 420  * address space into bus device space.
 421  */
 422 int
 423 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 424 {
 425         if (map != NULL) {
 426                 if (STAILQ_FIRST(&map->bpages) != NULL)
 427                         return (EBUSY);
 428                 kfree(map, M_DEVBUF);
 429         }
 430         dmat->map_count--;
 431         return (0);
 432 }
 433
 434 static __inline bus_size_t
 435 check_kmalloc(bus_dma_tag_t dmat, const void *vaddr0, int verify)
 436 {
 437         bus_size_t maxsize = 0;
 438         uintptr_t vaddr = (uintptr_t)vaddr0;
 439
 440         if ((vaddr ^ (vaddr + dmat->maxsize - 1)) & ~PAGE_MASK) {
 441                 if (verify || bootverbose)
 442                         kprintf("boundary check failed\n");
 443                 if (verify)
 444                         print_backtrace(-1); /* XXX panic */
 445                 maxsize = dmat->maxsize;
 446         }
 447         if (vaddr & (dmat->alignment - 1)) {
 448                 if (verify || bootverbose)
 449                         kprintf("alignment check failed\n");
 450                 if (verify)
 451                         print_backtrace(-1); /* XXX panic */
 452                 if (dmat->maxsize < dmat->alignment)
 453                         maxsize = dmat->alignment;
 454                 else
 455                         maxsize = dmat->maxsize;
 456         }
 457         return maxsize;
 458 }
 459
 460 /*
 461  * Allocate a piece of memory that can be efficiently mapped into
 462  * bus device space based on the constraints lited in the dma tag.
 463  *
 464  * mapp is degenerate.  By definition this allocation should not require
 465  * bounce buffers so do not allocate a dma map.
 466  */
 467 int
 468 bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr, int flags,
 469                  bus_dmamap_t *mapp)
 470 {
 471         int mflags;
 472
 473         /* If we succeed, no mapping/bouncing will be required */
 474         *mapp = NULL;
 475
 476         if (dmat->segments == NULL) {
 477                 KKASSERT(dmat->nsegments < 16384);
 478                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 479                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 480         }
 481
 482         if (flags & BUS_DMA_NOWAIT)
 483                 mflags = M_NOWAIT;
 484         else
 485                 mflags = M_WAITOK;
 486         if (flags & BUS_DMA_ZERO)
 487                 mflags |= M_ZERO;
 488
 489         if (BUS_DMAMEM_KMALLOC(dmat)) {
 490                 bus_size_t maxsize;
 491
 492                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 493
 494                 /*
 495                  * XXX
 496                  * Check whether the allocation
 497                  * - crossed a page boundary
 498                  * - was not aligned
 499                  * Retry with power-of-2 alignment in the above cases.
 500                  */
 501                 maxsize = check_kmalloc(dmat, *vaddr, 0);
 502                 if (maxsize) {
 503                         size_t size;
 504
 505                         kfree(*vaddr, M_DEVBUF);
 506                         /* XXX check for overflow? */
 507                         for (size = 1; size <= maxsize; size <<= 1)
 508                                 ;
 509                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 510                         check_kmalloc(dmat, *vaddr, 1);
 511                 }
 512         } else {
 513                 /*
 514                  * XXX Use Contigmalloc until it is merged into this facility
 515                  *     and handles multi-seg allocations.  Nobody is doing
 516                  *     multi-seg allocations yet though.
 517                  */
 518                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 519                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
 520         }
 521         if (*vaddr == NULL)
 522                 return (ENOMEM);
 523         return (0);
 524 }
 525
 526 /*
 527  * Free a piece of memory and it's allociated dmamap, that was allocated
 528  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 529  */
 530 void
 531 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 532 {
 533         /*
 534          * dmamem does not need to be bounced, so the map should be
 535          * NULL
 536          */
 537         if (map != NULL)
 538                 panic("bus_dmamem_free: Invalid map freed");
 539         if (BUS_DMAMEM_KMALLOC(dmat))
 540                 kfree(vaddr, M_DEVBUF);
 541         else
 542                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 543 }
 544
 545 static __inline vm_paddr_t
 546 _bus_dma_extract(pmap_t pmap, vm_offset_t vaddr)
 547 {
 548         if (pmap)
 549                 return pmap_extract(pmap, vaddr);
 550         else
 551                 return pmap_kextract(vaddr);
 552 }
 553
 554 /*
 555  * Utility function to load a linear buffer.  lastaddrp holds state
 556  * between invocations (for multiple-buffer loads).  segp contains
 557  * the segment following the starting one on entrace, and the ending
 558  * segment on exit.  first indicates if this is the first invocation
 559  * of this function.
 560  */
 561 static int
 562 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 563                         bus_dmamap_t map,
 564                         void *buf, bus_size_t buflen,
 565                         bus_dma_segment_t *segments,
 566                         int nsegments,
 567                         pmap_t pmap,
 568                         int flags,
 569                         vm_paddr_t *lastpaddrp,
 570                         int *segp,
 571                         int first)
 572 {
 573         vm_offset_t vaddr;
 574         vm_paddr_t paddr, nextpaddr;
 575         bus_dma_segment_t *sg;
 576         bus_addr_t bmask;
 577         int seg, error = 0;
 578
 579         if (map == NULL)
 580                 map = &nobounce_dmamap;
 581
 582 #ifdef INVARIANTS
 583         if (dmat->flags & BUS_DMA_ALIGNED)
 584                 KKASSERT(((uintptr_t)buf & (dmat->alignment - 1)) == 0);
 585 #endif
 586
 587         /*
 588          * If we are being called during a callback, pagesneeded will
 589          * be non-zero, so we can avoid doing the work twice.
 590          */
 591         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 592             map != &nobounce_dmamap && map->pagesneeded == 0) {
 593                 vm_offset_t vendaddr;
 594
 595                 /*
 596                  * Count the number of bounce pages
 597                  * needed in order to complete this transfer
 598                  */
 599                 vaddr = (vm_offset_t)buf;
 600                 vendaddr = (vm_offset_t)buf + buflen;
 601
 602                 while (vaddr < vendaddr) {
 603                         paddr = _bus_dma_extract(pmap, vaddr);
 604                         if (run_filter(dmat, paddr) != 0)
 605                                 map->pagesneeded++;
 606                         vaddr += (PAGE_SIZE - (vaddr & PAGE_MASK));
 607                 }
 608         }
 609
 610         /* Reserve Necessary Bounce Pages */
 611         if (map->pagesneeded != 0) {
 612                 struct bounce_zone *bz;
 613
 614                 bz = dmat->bounce_zone;
 615                 BZ_LOCK(bz);
 616                 if (flags & BUS_DMA_NOWAIT) {
 617                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
 618                                 BZ_UNLOCK(bz);
 619                                 error = ENOMEM;
 620                                 goto free_bounce;
 621                         }
 622                 } else {
 623                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
 624                                 /* Queue us for resources */
 625                                 map->dmat = dmat;
 626                                 map->buf = buf;
 627                                 map->buflen = buflen;
 628
 629                                 STAILQ_INSERT_TAIL(
 630                                     &dmat->bounce_zone->bounce_map_waitinglist,
 631                                     map, links);
 632                                 BZ_UNLOCK(bz);
 633
 634                                 return (EINPROGRESS);
 635                         }
 636                 }
 637                 BZ_UNLOCK(bz);
 638         }
 639
 640         KKASSERT(*segp >= 1 && *segp <= nsegments);
 641         seg = *segp;
 642         sg = &segments[seg - 1];
 643
 644         vaddr = (vm_offset_t)buf;
 645         nextpaddr = *lastpaddrp;
 646         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 647
 648         /* force at least one segment */
 649         do {
 650                 bus_size_t size;
 651
 652                 /*
 653                  * Per-page main loop
 654                  */
 655                 paddr = _bus_dma_extract(pmap, vaddr);
 656                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 657                 if (size > buflen)
 658                         size = buflen;
 659                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 660                         /*
 661                          * note: this paddr has the same in-page offset
 662                          * as vaddr and thus the paddr above, so the
 663                          * size does not have to be recalculated
 664                          */
 665                         paddr = add_bounce_page(dmat, map, vaddr, size);
 666                 }
 667
 668                 /*
 669                  * Fill in the bus_dma_segment
 670                  */
 671                 if (first) {
 672                         sg->ds_addr = paddr;
 673                         sg->ds_len = size;
 674                         first = 0;
 675                 } else if (paddr == nextpaddr) {
 676                         sg->ds_len += size;
 677                 } else {
 678                         sg++;
 679                         seg++;
 680                         if (seg > nsegments)
 681                                 break;
 682                         sg->ds_addr = paddr;
 683                         sg->ds_len = size;
 684                 }
 685                 nextpaddr = paddr + size;
 686
 687                 /*
 688                  * Handle maxsegsz and boundary issues with a nested loop
 689                  */
 690                 for (;;) {
 691                         bus_size_t tmpsize;
 692
 693                         /*
 694                          * Limit to the boundary and maximum segment size
 695                          */
 696                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 697                                 tmpsize = dmat->boundary -
 698                                           (sg->ds_addr & ~bmask);
 699                                 if (tmpsize > dmat->maxsegsz)
 700                                         tmpsize = dmat->maxsegsz;
 701                                 KKASSERT(tmpsize < sg->ds_len);
 702                         } else if (sg->ds_len > dmat->maxsegsz) {
 703                                 tmpsize = dmat->maxsegsz;
 704                         } else {
 705                                 break;
 706                         }
 707
 708                         /*
 709                          * Futz, split the data into a new segment.
 710                          */
 711                         if (seg >= nsegments)
 712                                 goto fail;
 713                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 714                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 715                         sg[0].ds_len = tmpsize;
 716                         sg++;
 717                         seg++;
 718                 }
 719
 720                 /*
 721                  * Adjust for loop
 722                  */
 723                 buflen -= size;
 724                 vaddr += size;
 725         } while (buflen > 0);
 726 fail:
 727         if (buflen != 0)
 728                 error = EFBIG;
 729
 730         *segp = seg;
 731         *lastpaddrp = nextpaddr;
 732
 733 free_bounce:
 734         if (error && (dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 735             map != &nobounce_dmamap) {
 736                 _bus_dmamap_unload(dmat, map);
 737                 return_bounce_pages(dmat, map);
 738         }
 739         return error;
 740 }
 741
 742 /*
 743  * Map the buffer buf into bus space using the dmamap map.
 744  */
 745 int
 746 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 747                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 748                 void *callback_arg, int flags)
 749 {
 750         vm_paddr_t lastaddr = 0;
 751         int error, nsegs = 1;
 752
 753         if (map != NULL) {
 754                 /*
 755                  * XXX
 756                  * Follow old semantics.  Once all of the callers are fixed,
 757                  * we should get rid of these internal flag "adjustment".
 758                  */
 759                 flags &= ~BUS_DMA_NOWAIT;
 760                 flags |= BUS_DMA_WAITOK;
 761
 762                 map->callback = callback;
 763                 map->callback_arg = callback_arg;
 764         }
 765
 766         error = _bus_dmamap_load_buffer(dmat, map, buf, buflen,
 767                         dmat->segments, dmat->nsegments,
 768                         NULL, flags, &lastaddr, &nsegs, 1);
 769         if (error == EINPROGRESS)
 770                 return error;
 771
 772         callback(callback_arg, dmat->segments, nsegs, error);
 773         return 0;
 774 }
 775
 776 /*
 777  * Like _bus_dmamap_load(), but for mbufs.
 778  */
 779 int
 780 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 781                      struct mbuf *m0,
 782                      bus_dmamap_callback2_t *callback, void *callback_arg,
 783                      int flags)
 784 {
 785         int nsegs, error;
 786
 787         /*
 788          * XXX
 789          * Follow old semantics.  Once all of the callers are fixed,
 790          * we should get rid of these internal flag "adjustment".
 791          */
 792         flags &= ~BUS_DMA_WAITOK;
 793         flags |= BUS_DMA_NOWAIT;
 794
 795         error = bus_dmamap_load_mbuf_segment(dmat, map, m0,
 796                         dmat->segments, dmat->nsegments, &nsegs, flags);
 797         if (error) {
 798                 /* force "no valid mappings" in callback */
 799                 callback(callback_arg, dmat->segments, 0, 0, error);
 800         } else {
 801                 callback(callback_arg, dmat->segments, nsegs,
 802                          m0->m_pkthdr.len, error);
 803         }
 804         return error;
 805 }
 806
 807 int
 808 bus_dmamap_load_mbuf_segment(bus_dma_tag_t dmat, bus_dmamap_t map,
 809                              struct mbuf *m0,
 810                              bus_dma_segment_t *segs, int maxsegs,
 811                              int *nsegs, int flags)
 812 {
 813         int error;
 814
 815         M_ASSERTPKTHDR(m0);
 816
 817         KASSERT(maxsegs >= 1, ("invalid maxsegs %d", maxsegs));
 818         KASSERT(maxsegs <= dmat->nsegments,
 819                 ("%d too many segments, dmat only supports %d segments",
 820                  maxsegs, dmat->nsegments));
 821         KASSERT(flags & BUS_DMA_NOWAIT,
 822                 ("only BUS_DMA_NOWAIT is supported"));
 823
 824         if (m0->m_pkthdr.len <= dmat->maxsize) {
 825                 int first = 1;
 826                 vm_paddr_t lastaddr = 0;
 827                 struct mbuf *m;
 828
 829                 *nsegs = 1;
 830                 error = 0;
 831                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 832                         if (m->m_len == 0)
 833                                 continue;
 834
 835                         error = _bus_dmamap_load_buffer(dmat, map,
 836                                         m->m_data, m->m_len,
 837                                         segs, maxsegs,
 838                                         NULL, flags, &lastaddr,
 839                                         nsegs, first);
 840                         if (error == ENOMEM && !first) {
 841                                 /*
 842                                  * Out of bounce pages due to too many
 843                                  * fragments in the mbuf chain; return
 844                                  * EFBIG instead.
 845                                  */
 846                                 error = EFBIG;
 847                         }
 848                         first = 0;
 849                 }
 850 #ifdef INVARIANTS
 851                 if (!error)
 852                         KKASSERT(*nsegs <= maxsegs && *nsegs >= 1);
 853 #endif
 854         } else {
 855                 *nsegs = 0;
 856                 error = EINVAL;
 857         }
 858         KKASSERT(error != EINPROGRESS);
 859         return error;
 860 }
 861
 862 /*
 863  * Like _bus_dmamap_load(), but for uios.
 864  */
 865 int
 866 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 867                     struct uio *uio,
 868                     bus_dmamap_callback2_t *callback, void *callback_arg,
 869                     int flags)
 870 {
 871         vm_paddr_t lastaddr;
 872         int nsegs, error, first, i;
 873         bus_size_t resid;
 874         struct iovec *iov;
 875         pmap_t pmap;
 876
 877         /*
 878          * XXX
 879          * Follow old semantics.  Once all of the callers are fixed,
 880          * we should get rid of these internal flag "adjustment".
 881          */
 882         flags &= ~BUS_DMA_WAITOK;
 883         flags |= BUS_DMA_NOWAIT;
 884
 885         resid = (bus_size_t)uio->uio_resid;
 886         iov = uio->uio_iov;
 887
 888         if (uio->uio_segflg == UIO_USERSPACE) {
 889                 struct thread *td;
 890
 891                 td = uio->uio_td;
 892                 KASSERT(td != NULL && td->td_proc != NULL,
 893                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 894                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 895         } else {
 896                 pmap = NULL;
 897         }
 898
 899         error = 0;
 900         nsegs = 1;
 901         first = 1;
 902         lastaddr = 0;
 903         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 904                 /*
 905                  * Now at the first iovec to load.  Load each iovec
 906                  * until we have exhausted the residual count.
 907                  */
 908                 bus_size_t minlen =
 909                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 910                 caddr_t addr = (caddr_t) iov[i].iov_base;
 911
 912                 error = _bus_dmamap_load_buffer(dmat, map, addr, minlen,
 913                                 dmat->segments, dmat->nsegments,
 914                                 pmap, flags, &lastaddr, &nsegs, first);
 915                 first = 0;
 916
 917                 resid -= minlen;
 918         }
 919
 920         if (error) {
 921                 /* force "no valid mappings" in callback */
 922                 callback(callback_arg, dmat->segments, 0, 0, error);
 923         } else {
 924                 callback(callback_arg, dmat->segments, nsegs,
 925                          (bus_size_t)uio->uio_resid, error);
 926         }
 927         return error;
 928 }
 929
 930 /*
 931  * Release the mapping held by map.
 932  */
 933 void
 934 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 935 {
 936         struct bounce_page *bpage;
 937
 938         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 939                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 940                 free_bounce_page(dmat, bpage);
 941         }
 942 }
 943
 944 void
 945 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 946 {
 947         struct bounce_page *bpage;
 948
 949         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 950                 /*
 951                  * Handle data bouncing.  We might also
 952                  * want to add support for invalidating
 953                  * the caches on broken hardware
 954                  */
 955                 switch (op) {
 956                 case BUS_DMASYNC_PREWRITE:
 957                         while (bpage != NULL) {
 958                                 bcopy((void *)bpage->datavaddr,
 959                                       (void *)bpage->vaddr,
 960                                       bpage->datacount);
 961                                 bpage = STAILQ_NEXT(bpage, links);
 962                         }
 963                         dmat->bounce_zone->total_bounced++;
 964                         break;
 965
 966                 case BUS_DMASYNC_POSTREAD:
 967                         while (bpage != NULL) {
 968                                 bcopy((void *)bpage->vaddr,
 969                                       (void *)bpage->datavaddr,
 970                                       bpage->datacount);
 971                                 bpage = STAILQ_NEXT(bpage, links);
 972                         }
 973                         dmat->bounce_zone->total_bounced++;
 974                         break;
 975
 976                 case BUS_DMASYNC_PREREAD:
 977                 case BUS_DMASYNC_POSTWRITE:
 978                         /* No-ops */
 979                         break;
 980                 }
 981         }
 982 }
 983
 984 static int
 985 alloc_bounce_zone(bus_dma_tag_t dmat)
 986 {
 987         struct bounce_zone *bz, *new_bz;
 988
 989         KASSERT(dmat->bounce_zone == NULL,
 990                 ("bounce zone was already assigned"));
 991
 992         new_bz = kmalloc(sizeof(*new_bz), M_DEVBUF, M_INTWAIT | M_ZERO);
 993
 994         lwkt_gettoken(&bounce_zone_tok);
 995
 996         /* Check to see if we already have a suitable zone */
 997         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
 998                 if (dmat->alignment <= bz->alignment &&
 999                     dmat->lowaddr >= bz->lowaddr) {
1000                         lwkt_reltoken(&bounce_zone_tok);
1001
1002                         dmat->bounce_zone = bz;
1003                         kfree(new_bz, M_DEVBUF);
1004                         return 0;
1005                 }
1006         }
1007         bz = new_bz;
1008
1009         spin_init(&bz->spin);
1010         STAILQ_INIT(&bz->bounce_page_list);
1011         STAILQ_INIT(&bz->bounce_map_waitinglist);
1012         bz->free_bpages = 0;
1013         bz->reserved_bpages = 0;
1014         bz->active_bpages = 0;
1015         bz->lowaddr = dmat->lowaddr;
1016         bz->alignment = round_page(dmat->alignment);
1017         ksnprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1018         busdma_zonecount++;
1019         ksnprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1020         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1021
1022         lwkt_reltoken(&bounce_zone_tok);
1023
1024         dmat->bounce_zone = bz;
1025
1026         sysctl_ctx_init(&bz->sysctl_ctx);
1027         bz->sysctl_tree = SYSCTL_ADD_NODE(&bz->sysctl_ctx,
1028             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1029             CTLFLAG_RD, 0, "");
1030         if (bz->sysctl_tree == NULL) {
1031                 sysctl_ctx_free(&bz->sysctl_ctx);
1032                 return 0;       /* XXX error code? */
1033         }
1034
1035         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1036             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1037             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1038             "Total bounce pages");
1039         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1040             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1041             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1042             "Free bounce pages");
1043         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1044             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1045             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1046             "Reserved bounce pages");
1047         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1048             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1049             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1050             "Active bounce pages");
1051         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1052             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1053             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1054             "Total bounce requests");
1055         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1056             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1057             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1058             "Total bounce requests that were deferred");
1059         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1060             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1061             "reserve_failed", CTLFLAG_RD, &bz->reserve_failed, 0,
1062             "Total bounce page reservations that were failed");
1063         SYSCTL_ADD_STRING(&bz->sysctl_ctx,
1064             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1065             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1066         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1067             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1068             "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
1069
1070         return 0;
1071 }
1072
1073 static int
1074 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages, int flags)
1075 {
1076         struct bounce_zone *bz = dmat->bounce_zone;
1077         int count = 0, mflags;
1078
1079         if (flags & BUS_DMA_NOWAIT)
1080                 mflags = M_NOWAIT;
1081         else
1082                 mflags = M_WAITOK;
1083
1084         while (numpages > 0) {
1085                 struct bounce_page *bpage;
1086
1087                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
1088
1089                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1090                                                          mflags, 0ul,
1091                                                          bz->lowaddr,
1092                                                          bz->alignment, 0);
1093                 if (bpage->vaddr == 0) {
1094                         kfree(bpage, M_DEVBUF);
1095                         break;
1096                 }
1097                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1098
1099                 BZ_LOCK(bz);
1100                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1101                 total_bounce_pages++;
1102                 bz->total_bpages++;
1103                 bz->free_bpages++;
1104                 BZ_UNLOCK(bz);
1105
1106                 count++;
1107                 numpages--;
1108         }
1109         return count;
1110 }
1111
1112 /* Assume caller holds bounce zone spinlock */
1113 static int
1114 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1115 {
1116         struct bounce_zone *bz = dmat->bounce_zone;
1117         int pages;
1118
1119         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1120         if (!commit && map->pagesneeded > (map->pagesreserved + pages)) {
1121                 bz->reserve_failed++;
1122                 return (map->pagesneeded - (map->pagesreserved + pages));
1123         }
1124
1125         bz->free_bpages -= pages;
1126
1127         bz->reserved_bpages += pages;
1128         KKASSERT(bz->reserved_bpages <= bz->total_bpages);
1129
1130         map->pagesreserved += pages;
1131         pages = map->pagesneeded - map->pagesreserved;
1132
1133         return pages;
1134 }
1135
1136 static void
1137 return_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
1138 {
1139         struct bounce_zone *bz = dmat->bounce_zone;
1140         int reserved = map->pagesreserved;
1141         bus_dmamap_t wait_map;
1142
1143         map->pagesreserved = 0;
1144         map->pagesneeded = 0;
1145
1146         if (reserved == 0)
1147                 return;
1148
1149         BZ_LOCK(bz);
1150
1151         bz->free_bpages += reserved;
1152         KKASSERT(bz->free_bpages <= bz->total_bpages);
1153
1154         KKASSERT(bz->reserved_bpages >= reserved);
1155         bz->reserved_bpages -= reserved;
1156
1157         wait_map = get_map_waiting(dmat);
1158
1159         BZ_UNLOCK(bz);
1160
1161         if (wait_map != NULL)
1162                 add_map_callback(map);
1163 }
1164
1165 static bus_addr_t
1166 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1167                 bus_size_t size)
1168 {
1169         struct bounce_zone *bz = dmat->bounce_zone;
1170         struct bounce_page *bpage;
1171
1172         KASSERT(map->pagesneeded > 0, ("map doesn't need any pages"));
1173         map->pagesneeded--;
1174
1175         KASSERT(map->pagesreserved > 0, ("map doesn't reserve any pages"));
1176         map->pagesreserved--;
1177
1178         BZ_LOCK(bz);
1179
1180         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1181         KASSERT(bpage != NULL, ("free page list is empty"));
1182         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1183
1184         KKASSERT(bz->reserved_bpages > 0);
1185         bz->reserved_bpages--;
1186
1187         bz->active_bpages++;
1188         KKASSERT(bz->active_bpages <= bz->total_bpages);
1189
1190         BZ_UNLOCK(bz);
1191
1192         bpage->datavaddr = vaddr;
1193         bpage->datacount = size;
1194         STAILQ_INSERT_TAIL(&map->bpages, bpage, links);
1195         return bpage->busaddr;
1196 }
1197
1198 static void
1199 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1200 {
1201         struct bounce_zone *bz = dmat->bounce_zone;
1202         bus_dmamap_t map;
1203
1204         bpage->datavaddr = 0;
1205         bpage->datacount = 0;
1206
1207         BZ_LOCK(bz);
1208
1209         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1210
1211         bz->free_bpages++;
1212         KKASSERT(bz->free_bpages <= bz->total_bpages);
1213
1214         KKASSERT(bz->active_bpages > 0);
1215         bz->active_bpages--;
1216
1217         map = get_map_waiting(dmat);
1218
1219         BZ_UNLOCK(bz);
1220
1221         if (map != NULL)
1222                 add_map_callback(map);
1223 }
1224
1225 /* Assume caller holds bounce zone spinlock */
1226 static bus_dmamap_t
1227 get_map_waiting(bus_dma_tag_t dmat)
1228 {
1229         struct bounce_zone *bz = dmat->bounce_zone;
1230         bus_dmamap_t map;
1231
1232         map = STAILQ_FIRST(&bz->bounce_map_waitinglist);
1233         if (map != NULL) {
1234                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1235                         STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
1236                         bz->total_deferred++;
1237                 } else {
1238                         map = NULL;
1239                 }
1240         }
1241         return map;
1242 }
1243
1244 static void
1245 add_map_callback(bus_dmamap_t map)
1246 {
1247 #ifdef notyet
1248         /* XXX callbacklist is not MPSAFE */
1249         crit_enter();
1250         get_mplock();
1251         STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
1252         busdma_swi_pending = 1;
1253         setsoftvm();
1254         rel_mplock();
1255         crit_exit();
1256 #else
1257         panic("%s uncoded", __func__);
1258 #endif
1259 }
1260
1261 #ifdef notyet
1262 void
1263 busdma_swi(void)
1264 {
1265         bus_dmamap_t map;
1266
1267         crit_enter();
1268         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1269                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1270                 crit_exit();
1271                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
1272                                 map->callback, map->callback_arg, /*flags*/0);
1273                 crit_enter();
1274         }
1275         crit_exit();
1276 }
1277 #endif