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