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