sys/platform/pc32/i386/busdma_machdep.c

   1 /*
   2  * Copyright (c) 1997, 1998 Justin T. Gibbs.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions, and the following disclaimer,
  10  *    without modification, immediately at the beginning of the file.
  11  * 2. The name of the author may not be used to endorse or promote products
  12  *    derived from this software without specific prior written permission.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  18  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/i386/i386/busdma_machdep.c,v 1.94 2008/08/15 20:51:31 kmacy Exp $
  27  * $DragonFly: src/sys/platform/pc32/i386/busdma_machdep.c,v 1.23 2008/06/05 18:06:32 swildner Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/malloc.h>
  33 #include <sys/mbuf.h>
  34 #include <sys/uio.h>
  35 #include <sys/thread2.h>
  36 #include <sys/bus_dma.h>
  37 #include <sys/kernel.h>
  38 #include <sys/sysctl.h>
  39 #include <sys/lock.h>
  40 #include <sys/spinlock2.h>
  41
  42 #include <vm/vm.h>
  43 #include <vm/vm_page.h>
  44
  45 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  46 #include <sys/proc.h>
  47 #include <sys/lock.h>
  48 #include <vm/vm_map.h>
  49
  50 #include <machine/md_var.h>
  51
  52 #define MAX_BPAGES      1024
  53
  54 /*
  55  * 16 x N declared on stack.
  56  */
  57 #define BUS_DMA_CACHE_SEGMENTS  8
  58
  59 struct bounce_zone;
  60 struct bus_dmamap;
  61
  62 struct bus_dma_tag {
  63         bus_dma_tag_t   parent;
  64         bus_size_t      alignment;
  65         bus_size_t      boundary;
  66         bus_addr_t      lowaddr;
  67         bus_addr_t      highaddr;
  68         bus_dma_filter_t *filter;
  69         void            *filterarg;
  70         bus_size_t      maxsize;
  71         u_int           nsegments;
  72         bus_size_t      maxsegsz;
  73         int             flags;
  74         int             ref_count;
  75         int             map_count;
  76         bus_dma_segment_t *segments;
  77         struct bounce_zone *bounce_zone;
  78 #ifdef SMP
  79         struct spinlock spin;
  80 #else
  81         int             unused0;
  82 #endif
  83 };
  84
  85 /*
  86  * bus_dma_tag private flags
  87  */
  88 #define BUS_DMA_BOUNCE_ALIGN    BUS_DMA_BUS2
  89 #define BUS_DMA_BOUNCE_LOWADDR  BUS_DMA_BUS3
  90 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  91
  92 #define BUS_DMA_COULD_BOUNCE    (BUS_DMA_BOUNCE_LOWADDR | BUS_DMA_BOUNCE_ALIGN)
  93
  94 #define BUS_DMAMEM_KMALLOC(dmat) \
  95         ((dmat)->maxsize <= PAGE_SIZE && \
  96          (dmat)->alignment <= PAGE_SIZE && \
  97          (dmat)->lowaddr >= ptoa(Maxmem))
  98
  99 struct bounce_page {
 100         vm_offset_t     vaddr;          /* kva of bounce buffer */
 101         bus_addr_t      busaddr;        /* Physical address */
 102         vm_offset_t     datavaddr;      /* kva of client data */
 103         bus_size_t      datacount;      /* client data count */
 104         STAILQ_ENTRY(bounce_page) links;
 105 };
 106
 107 struct bounce_zone {
 108         STAILQ_ENTRY(bounce_zone) links;
 109         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
 110         STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 111 #ifdef SMP
 112         struct spinlock spin;
 113 #else
 114         int             unused0;
 115 #endif
 116         int             total_bpages;
 117         int             free_bpages;
 118         int             reserved_bpages;
 119         int             active_bpages;
 120         int             total_bounced;
 121         int             total_deferred;
 122         int             reserve_failed;
 123         bus_size_t      alignment;
 124         bus_addr_t      lowaddr;
 125         char            zoneid[8];
 126         char            lowaddrid[20];
 127         struct sysctl_ctx_list sysctl_ctx;
 128         struct sysctl_oid *sysctl_tree;
 129 };
 130
 131 #ifdef SMP
 132 #define BZ_LOCK(bz)     spin_lock_wr(&(bz)->spin)
 133 #define BZ_UNLOCK(bz)   spin_unlock_wr(&(bz)->spin)
 134 #else
 135 #define BZ_LOCK(bz)     crit_enter()
 136 #define BZ_UNLOCK(bz)   crit_exit()
 137 #endif
 138
 139 static struct lwkt_token bounce_zone_tok =
 140         LWKT_TOKEN_INITIALIZER(bounce_zone_tok);
 141 static int busdma_zonecount;
 142 static STAILQ_HEAD(, bounce_zone) bounce_zone_list =
 143         STAILQ_HEAD_INITIALIZER(bounce_zone_list);
 144
 145 int busdma_swi_pending;
 146 static int total_bounce_pages;
 147 static int max_bounce_pages = MAX_BPAGES;
 148 static int bounce_alignment = 1; /* XXX temporary */
 149
 150 TUNABLE_INT("hw.busdma.max_bpages", &max_bounce_pages);
 151 TUNABLE_INT("hw.busdma.bounce_alignment", &bounce_alignment);
 152
 153 struct bus_dmamap {
 154         struct bp_list  bpages;
 155         int             pagesneeded;
 156         int             pagesreserved;
 157         bus_dma_tag_t   dmat;
 158         void            *buf;           /* unmapped buffer pointer */
 159         bus_size_t      buflen;         /* unmapped buffer length */
 160         bus_dmamap_callback_t *callback;
 161         void            *callback_arg;
 162         STAILQ_ENTRY(bus_dmamap) links;
 163 };
 164
 165 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist =
 166         STAILQ_HEAD_INITIALIZER(bounce_map_callbacklist);
 167
 168 static struct bus_dmamap nobounce_dmamap;
 169
 170 static int              alloc_bounce_zone(bus_dma_tag_t);
 171 static int              alloc_bounce_pages(bus_dma_tag_t, u_int, int);
 172 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
 173 static void             return_bounce_pages(bus_dma_tag_t, bus_dmamap_t);
 174 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
 175                             vm_offset_t, bus_size_t);
 176 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
 177
 178 static bus_dmamap_t     get_map_waiting(bus_dma_tag_t);
 179 static void             add_map_callback(bus_dmamap_t);
 180
 181 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 182 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bounce_pages,
 183            0, "Total bounce pages");
 184 SYSCTL_INT(_hw_busdma, OID_AUTO, max_bpages, CTLFLAG_RD, &max_bounce_pages,
 185            0, "Max bounce pages per bounce zone");
 186 SYSCTL_INT(_hw_busdma, OID_AUTO, bounce_alignment, CTLFLAG_RD,
 187            &bounce_alignment, 0, "Obey alignment constraint");
 188
 189 static __inline int
 190 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 191 {
 192         int retval;
 193
 194         retval = 0;
 195         do {
 196                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr) ||
 197                      (bounce_alignment && (paddr & (dmat->alignment - 1)) != 0))
 198                  && (dmat->filter == NULL ||
 199                      dmat->filter(dmat->filterarg, paddr) != 0))
 200                         retval = 1;
 201
 202                 dmat = dmat->parent;
 203         } while (retval == 0 && dmat != NULL);
 204         return (retval);
 205 }
 206
 207 static __inline
 208 bus_dma_segment_t *
 209 bus_dma_tag_lock(bus_dma_tag_t tag, bus_dma_segment_t *cache)
 210 {
 211         if (tag->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 212                 return(cache);
 213 #ifdef SMP
 214         spin_lock_wr(&tag->spin);
 215 #endif
 216         return(tag->segments);
 217 }
 218
 219 static __inline
 220 void
 221 bus_dma_tag_unlock(bus_dma_tag_t tag)
 222 {
 223 #ifdef SMP
 224         if (tag->nsegments > BUS_DMA_CACHE_SEGMENTS)
 225                 spin_unlock_wr(&tag->spin);
 226 #endif
 227 }
 228
 229 /*
 230  * Allocate a device specific dma_tag.
 231  */
 232 int
 233 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 234                    bus_size_t boundary, bus_addr_t lowaddr,
 235                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 236                    void *filterarg, bus_size_t maxsize, int nsegments,
 237                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 238 {
 239         bus_dma_tag_t newtag;
 240         int error = 0;
 241
 242         /*
 243          * Sanity checks
 244          */
 245
 246         if (alignment == 0)
 247                 alignment = 1;
 248         if (alignment & (alignment - 1))
 249                 panic("alignment must be power of 2\n");
 250
 251         if (boundary != 0) {
 252                 if (boundary & (boundary - 1))
 253                         panic("boundary must be power of 2\n");
 254                 if (boundary < maxsegsz) {
 255                         kprintf("boundary < maxsegsz:\n");
 256                         print_backtrace();
 257                         maxsegsz = boundary;
 258                 }
 259         }
 260
 261         /* Return a NULL tag on failure */
 262         *dmat = NULL;
 263
 264         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT | M_ZERO);
 265
 266         spin_init(&newtag->spin);
 267         newtag->parent = parent;
 268         newtag->alignment = alignment;
 269         newtag->boundary = boundary;
 270         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 271         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 272         newtag->filter = filter;
 273         newtag->filterarg = filterarg;
 274         newtag->maxsize = maxsize;
 275         newtag->nsegments = nsegments;
 276         newtag->maxsegsz = maxsegsz;
 277         newtag->flags = flags;
 278         newtag->ref_count = 1; /* Count ourself */
 279         newtag->map_count = 0;
 280         newtag->segments = NULL;
 281         newtag->bounce_zone = NULL;
 282
 283         /* Take into account any restrictions imposed by our parent tag */
 284         if (parent != NULL) {
 285                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 286                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 287
 288                 if (newtag->boundary == 0) {
 289                         newtag->boundary = parent->boundary;
 290                 } else if (parent->boundary != 0) {
 291                         newtag->boundary = MIN(parent->boundary,
 292                                                newtag->boundary);
 293                 }
 294
 295 #ifdef notyet
 296                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
 297 #endif
 298
 299                 if (newtag->filter == NULL) {
 300                         /*
 301                          * Short circuit looking at our parent directly
 302                          * since we have encapsulated all of its information
 303                          */
 304                         newtag->filter = parent->filter;
 305                         newtag->filterarg = parent->filterarg;
 306                         newtag->parent = parent->parent;
 307                 }
 308                 if (newtag->parent != NULL)
 309                         parent->ref_count++;
 310         }
 311
 312         if (newtag->lowaddr < ptoa(Maxmem))
 313                 newtag->flags |= BUS_DMA_BOUNCE_LOWADDR;
 314         if (bounce_alignment && newtag->alignment > 1 &&
 315             !(newtag->flags & BUS_DMA_ALIGNED))
 316                 newtag->flags |= BUS_DMA_BOUNCE_ALIGN;
 317
 318         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
 319             (flags & BUS_DMA_ALLOCNOW) != 0) {
 320                 struct bounce_zone *bz;
 321
 322                 /* Must bounce */
 323
 324                 error = alloc_bounce_zone(newtag);
 325                 if (error)
 326                         goto back;
 327                 bz = newtag->bounce_zone;
 328
 329                 if (ptoa(bz->total_bpages) < maxsize) {
 330                         int pages;
 331
 332                         if (flags & BUS_DMA_ONEBPAGE) {
 333                                 pages = 1;
 334                         } else {
 335                                 pages = atop(round_page(maxsize)) -
 336                                         bz->total_bpages;
 337                                 pages = MAX(pages, 1);
 338                         }
 339
 340                         /* Add pages to our bounce pool */
 341                         if (alloc_bounce_pages(newtag, pages, flags) < pages)
 342                                 error = ENOMEM;
 343
 344                         /* Performed initial allocation */
 345                         newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 346                 }
 347         }
 348 back:
 349         if (error)
 350                 kfree(newtag, M_DEVBUF);
 351         else
 352                 *dmat = newtag;
 353         return error;
 354 }
 355
 356 int
 357 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 358 {
 359         if (dmat != NULL) {
 360                 if (dmat->map_count != 0)
 361                         return (EBUSY);
 362
 363                 while (dmat != NULL) {
 364                         bus_dma_tag_t parent;
 365
 366                         parent = dmat->parent;
 367                         dmat->ref_count--;
 368                         if (dmat->ref_count == 0) {
 369                                 if (dmat->segments != NULL)
 370                                         kfree(dmat->segments, M_DEVBUF);
 371                                 kfree(dmat, M_DEVBUF);
 372                                 /*
 373                                  * Last reference count, so
 374                                  * release our reference
 375                                  * count on our parent.
 376                                  */
 377                                 dmat = parent;
 378                         } else
 379                                 dmat = NULL;
 380                 }
 381         }
 382         return (0);
 383 }
 384
 385 bus_size_t
 386 bus_dma_tag_getmaxsize(bus_dma_tag_t tag)
 387 {
 388         return(tag->maxsize);
 389 }
 390
 391 /*
 392  * Allocate a handle for mapping from kva/uva/physical
 393  * address space into bus device space.
 394  */
 395 int
 396 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 397 {
 398         int error;
 399
 400         error = 0;
 401
 402         if (dmat->segments == NULL) {
 403                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 404                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 405                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 406         }
 407
 408         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 409                 struct bounce_zone *bz;
 410                 int maxpages;
 411
 412                 /* Must bounce */
 413
 414                 if (dmat->bounce_zone == NULL) {
 415                         error = alloc_bounce_zone(dmat);
 416                         if (error)
 417                                 return error;
 418                 }
 419                 bz = dmat->bounce_zone;
 420
 421                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
 422
 423                 /* Initialize the new map */
 424                 STAILQ_INIT(&((*mapp)->bpages));
 425
 426                 /*
 427                  * Attempt to add pages to our pool on a per-instance
 428                  * basis up to a sane limit.
 429                  */
 430                 if (dmat->flags & BUS_DMA_BOUNCE_ALIGN) {
 431                         maxpages = max_bounce_pages;
 432                 } else {
 433                         maxpages = MIN(max_bounce_pages,
 434                                        Maxmem - atop(dmat->lowaddr));
 435                 }
 436                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 437                  || (dmat->map_count > 0
 438                   && bz->total_bpages < maxpages)) {
 439                         int pages;
 440
 441                         if (flags & BUS_DMA_ONEBPAGE) {
 442                                 pages = 1;
 443                         } else {
 444                                 pages = atop(round_page(dmat->maxsize));
 445                                 pages = MIN(maxpages - bz->total_bpages, pages);
 446                                 pages = MAX(pages, 1);
 447                         }
 448                         if (alloc_bounce_pages(dmat, pages, flags) < pages)
 449                                 error = ENOMEM;
 450
 451                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 452                                 if (!error)
 453                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 454                         } else {
 455                                 error = 0;
 456                         }
 457                 }
 458         } else {
 459                 *mapp = NULL;
 460         }
 461         if (!error)
 462                 dmat->map_count++;
 463         return error;
 464 }
 465
 466 /*
 467  * Destroy a handle for mapping from kva/uva/physical
 468  * address space into bus device space.
 469  */
 470 int
 471 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 472 {
 473         if (map != NULL) {
 474                 if (STAILQ_FIRST(&map->bpages) != NULL)
 475                         return (EBUSY);
 476                 kfree(map, M_DEVBUF);
 477         }
 478         dmat->map_count--;
 479         return (0);
 480 }
 481
 482 static __inline bus_size_t
 483 check_kmalloc(bus_dma_tag_t dmat, const void *vaddr0, int verify)
 484 {
 485         bus_size_t maxsize = 0;
 486         uintptr_t vaddr = (uintptr_t)vaddr0;
 487
 488         if ((vaddr ^ (vaddr + dmat->maxsize - 1)) & ~PAGE_MASK) {
 489                 kprintf("boundary check failed\n");
 490                 if (verify)
 491                         print_backtrace(); /* XXX panic */
 492                 maxsize = dmat->maxsize;
 493         }
 494         if (vaddr & (dmat->alignment - 1)) {
 495                 kprintf("alignment check failed\n");
 496                 if (verify)
 497                         print_backtrace(); /* XXX panic */
 498                 if (dmat->maxsize < dmat->alignment)
 499                         maxsize = dmat->alignment;
 500                 else
 501                         maxsize = dmat->maxsize;
 502         }
 503         return maxsize;
 504 }
 505
 506 /*
 507  * Allocate a piece of memory that can be efficiently mapped into
 508  * bus device space based on the constraints lited in the dma tag.
 509  *
 510  * mapp is degenerate.  By definition this allocation should not require
 511  * bounce buffers so do not allocate a dma map.
 512  */
 513 int
 514 bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr, int flags,
 515                  bus_dmamap_t *mapp)
 516 {
 517         int mflags;
 518
 519         /* If we succeed, no mapping/bouncing will be required */
 520         *mapp = NULL;
 521
 522         if (dmat->segments == NULL) {
 523                 KKASSERT(dmat->nsegments < 16384);
 524                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 525                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 526         }
 527
 528         if (flags & BUS_DMA_NOWAIT)
 529                 mflags = M_NOWAIT;
 530         else
 531                 mflags = M_WAITOK;
 532         if (flags & BUS_DMA_ZERO)
 533                 mflags |= M_ZERO;
 534
 535         if (BUS_DMAMEM_KMALLOC(dmat)) {
 536                 bus_size_t maxsize;
 537
 538                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 539
 540                 /*
 541                  * XXX
 542                  * Check whether the allocation
 543                  * - crossed a page boundary
 544                  * - was not aligned
 545                  * Retry with power-of-2 alignment in the above cases.
 546                  */
 547                 maxsize = check_kmalloc(dmat, *vaddr, 0);
 548                 if (maxsize) {
 549                         size_t size;
 550
 551                         kfree(*vaddr, M_DEVBUF);
 552                         /* XXX check for overflow? */
 553                         for (size = 1; size <= maxsize; size <<= 1)
 554                                 ;
 555                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 556                         check_kmalloc(dmat, *vaddr, 1);
 557                 }
 558         } else {
 559                 /*
 560                  * XXX Use Contigmalloc until it is merged into this facility
 561                  *     and handles multi-seg allocations.  Nobody is doing
 562                  *     multi-seg allocations yet though.
 563                  */
 564                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 565                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
 566         }
 567         if (*vaddr == NULL)
 568                 return (ENOMEM);
 569         return (0);
 570 }
 571
 572 /*
 573  * Free a piece of memory and it's allociated dmamap, that was allocated
 574  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 575  */
 576 void
 577 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 578 {
 579         /*
 580          * dmamem does not need to be bounced, so the map should be
 581          * NULL
 582          */
 583         if (map != NULL)
 584                 panic("bus_dmamem_free: Invalid map freed\n");
 585         if (BUS_DMAMEM_KMALLOC(dmat))
 586                 kfree(vaddr, M_DEVBUF);
 587         else
 588                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 589 }
 590
 591 static __inline vm_paddr_t
 592 _bus_dma_extract(pmap_t pmap, vm_offset_t vaddr)
 593 {
 594         if (pmap)
 595                 return pmap_extract(pmap, vaddr);
 596         else
 597                 return pmap_kextract(vaddr);
 598 }
 599
 600 /*
 601  * Utility function to load a linear buffer.  lastaddrp holds state
 602  * between invocations (for multiple-buffer loads).  segp contains
 603  * the segment following the starting one on entrace, and the ending
 604  * segment on exit.  first indicates if this is the first invocation
 605  * of this function.
 606  */
 607 static int
 608 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 609                         bus_dmamap_t map,
 610                         void *buf, bus_size_t buflen,
 611                         bus_dma_segment_t *segments,
 612                         int nsegments,
 613                         pmap_t pmap,
 614                         int flags,
 615                         vm_paddr_t *lastpaddrp,
 616                         int *segp,
 617                         int first)
 618 {
 619         vm_offset_t vaddr;
 620         vm_paddr_t paddr, nextpaddr;
 621         bus_dma_segment_t *sg;
 622         bus_addr_t bmask;
 623         int seg, error = 0;
 624
 625         if (map == NULL)
 626                 map = &nobounce_dmamap;
 627
 628 #ifdef INVARIANTS
 629         if (dmat->flags & BUS_DMA_ALIGNED)
 630                 KKASSERT(((uintptr_t)buf & (dmat->alignment - 1)) == 0);
 631 #endif
 632
 633         /*
 634          * If we are being called during a callback, pagesneeded will
 635          * be non-zero, so we can avoid doing the work twice.
 636          */
 637         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 638             map != &nobounce_dmamap && map->pagesneeded == 0) {
 639                 vm_offset_t vendaddr;
 640
 641                 /*
 642                  * Count the number of bounce pages
 643                  * needed in order to complete this transfer
 644                  */
 645                 vaddr = (vm_offset_t)buf;
 646                 vendaddr = (vm_offset_t)buf + buflen;
 647
 648                 while (vaddr < vendaddr) {
 649                         paddr = _bus_dma_extract(pmap, vaddr);
 650                         if (run_filter(dmat, paddr) != 0)
 651                                 map->pagesneeded++;
 652                         vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
 653                 }
 654         }
 655
 656         /* Reserve Necessary Bounce Pages */
 657         if (map->pagesneeded != 0) {
 658                 struct bounce_zone *bz;
 659
 660                 bz = dmat->bounce_zone;
 661                 BZ_LOCK(bz);
 662                 if (flags & BUS_DMA_NOWAIT) {
 663                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
 664                                 BZ_UNLOCK(bz);
 665                                 error = ENOMEM;
 666                                 goto free_bounce;
 667                         }
 668                 } else {
 669                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
 670                                 /* Queue us for resources */
 671                                 map->dmat = dmat;
 672                                 map->buf = buf;
 673                                 map->buflen = buflen;
 674
 675                                 STAILQ_INSERT_TAIL(
 676                                     &dmat->bounce_zone->bounce_map_waitinglist,
 677                                     map, links);
 678                                 BZ_UNLOCK(bz);
 679
 680                                 return (EINPROGRESS);
 681                         }
 682                 }
 683                 BZ_UNLOCK(bz);
 684         }
 685
 686         KKASSERT(*segp >= 1 && *segp <= nsegments);
 687         seg = *segp;
 688         sg = &segments[seg - 1];
 689
 690         vaddr = (vm_offset_t)buf;
 691         nextpaddr = *lastpaddrp;
 692         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 693
 694         /* force at least one segment */
 695         do {
 696                 bus_size_t size;
 697
 698                 /*
 699                  * Per-page main loop
 700                  */
 701                 paddr = _bus_dma_extract(pmap, vaddr);
 702                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 703                 if (size > buflen)
 704                         size = buflen;
 705                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 706                         /*
 707                          * note: this paddr has the same in-page offset
 708                          * as vaddr and thus the paddr above, so the
 709                          * size does not have to be recalculated
 710                          */
 711                         paddr = add_bounce_page(dmat, map, vaddr, size);
 712                 }
 713
 714                 /*
 715                  * Fill in the bus_dma_segment
 716                  */
 717                 if (first) {
 718                         sg->ds_addr = paddr;
 719                         sg->ds_len = size;
 720                         first = 0;
 721                 } else if (paddr == nextpaddr) {
 722                         sg->ds_len += size;
 723                 } else {
 724                         sg++;
 725                         seg++;
 726                         if (seg > nsegments)
 727                                 break;
 728                         sg->ds_addr = paddr;
 729                         sg->ds_len = size;
 730                 }
 731                 nextpaddr = paddr + size;
 732
 733                 /*
 734                  * Handle maxsegsz and boundary issues with a nested loop
 735                  */
 736                 for (;;) {
 737                         bus_size_t tmpsize;
 738
 739                         /*
 740                          * Limit to the boundary and maximum segment size
 741                          */
 742                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 743                                 tmpsize = dmat->boundary -
 744                                           (sg->ds_addr & ~bmask);
 745                                 if (tmpsize > dmat->maxsegsz)
 746                                         tmpsize = dmat->maxsegsz;
 747                                 KKASSERT(tmpsize < sg->ds_len);
 748                         } else if (sg->ds_len > dmat->maxsegsz) {
 749                                 tmpsize = dmat->maxsegsz;
 750                         } else {
 751                                 break;
 752                         }
 753
 754                         /*
 755                          * Futz, split the data into a new segment.
 756                          */
 757                         if (seg >= nsegments)
 758                                 goto fail;
 759                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 760                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 761                         sg[0].ds_len = tmpsize;
 762                         sg++;
 763                         seg++;
 764                 }
 765
 766                 /*
 767                  * Adjust for loop
 768                  */
 769                 buflen -= size;
 770                 vaddr += size;
 771         } while (buflen > 0);
 772 fail:
 773         if (buflen != 0)
 774                 error = EFBIG;
 775
 776         *segp = seg;
 777         *lastpaddrp = nextpaddr;
 778
 779 free_bounce:
 780         if (error && (dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 781             map != &nobounce_dmamap) {
 782                 _bus_dmamap_unload(dmat, map);
 783                 return_bounce_pages(dmat, map);
 784         }
 785         return error;
 786 }
 787
 788 /*
 789  * Map the buffer buf into bus space using the dmamap map.
 790  */
 791 int
 792 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 793                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 794                 void *callback_arg, int flags)
 795 {
 796         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 797         bus_dma_segment_t *segments;
 798         vm_paddr_t lastaddr = 0;
 799         int error, nsegs = 1;
 800
 801         if (map != NULL) {
 802                 /*
 803                  * XXX
 804                  * Follow old semantics.  Once all of the callers are fixed,
 805                  * we should get rid of these internal flag "adjustment".
 806                  */
 807                 flags &= ~BUS_DMA_NOWAIT;
 808                 flags |= BUS_DMA_WAITOK;
 809
 810                 map->callback = callback;
 811                 map->callback_arg = callback_arg;
 812         }
 813
 814         segments = bus_dma_tag_lock(dmat, cache_segments);
 815         error = _bus_dmamap_load_buffer(dmat, map, buf, buflen,
 816                         segments, dmat->nsegments,
 817                         NULL, flags, &lastaddr, &nsegs, 1);
 818         if (error == EINPROGRESS) {
 819                 bus_dma_tag_unlock(dmat);
 820                 return error;
 821         }
 822         callback(callback_arg, segments, nsegs, error);
 823         bus_dma_tag_unlock(dmat);
 824         return 0;
 825 }
 826
 827 /*
 828  * Like _bus_dmamap_load(), but for mbufs.
 829  */
 830 int
 831 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 832                      struct mbuf *m0,
 833                      bus_dmamap_callback2_t *callback, void *callback_arg,
 834                      int flags)
 835 {
 836         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 837         bus_dma_segment_t *segments;
 838         int nsegs, error;
 839
 840         /*
 841          * XXX
 842          * Follow old semantics.  Once all of the callers are fixed,
 843          * we should get rid of these internal flag "adjustment".
 844          */
 845         flags &= ~BUS_DMA_WAITOK;
 846         flags |= BUS_DMA_NOWAIT;
 847
 848         segments = bus_dma_tag_lock(dmat, cache_segments);
 849         error = bus_dmamap_load_mbuf_segment(dmat, map, m0,
 850                         segments, dmat->nsegments, &nsegs, flags);
 851         if (error) {
 852                 /* force "no valid mappings" in callback */
 853                 callback(callback_arg, segments, 0,
 854                          0, error);
 855         } else {
 856                 callback(callback_arg, segments, nsegs,
 857                          m0->m_pkthdr.len, error);
 858         }
 859         bus_dma_tag_unlock(dmat);
 860         return error;
 861 }
 862
 863 int
 864 bus_dmamap_load_mbuf_segment(bus_dma_tag_t dmat, bus_dmamap_t map,
 865                              struct mbuf *m0,
 866                              bus_dma_segment_t *segs, int maxsegs,
 867                              int *nsegs, int flags)
 868 {
 869         int error;
 870
 871         M_ASSERTPKTHDR(m0);
 872
 873         KASSERT(maxsegs >= 1, ("invalid maxsegs %d\n", maxsegs));
 874         KASSERT(maxsegs <= dmat->nsegments,
 875                 ("%d too many segments, dmat only support %d segments\n",
 876                  maxsegs, dmat->nsegments));
 877         KASSERT(flags & BUS_DMA_NOWAIT,
 878                 ("only BUS_DMA_NOWAIT is supported\n"));
 879
 880         if (m0->m_pkthdr.len <= dmat->maxsize) {
 881                 int first = 1;
 882                 vm_paddr_t lastaddr = 0;
 883                 struct mbuf *m;
 884
 885                 *nsegs = 1;
 886                 error = 0;
 887                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 888                         if (m->m_len == 0)
 889                                 continue;
 890
 891                         error = _bus_dmamap_load_buffer(dmat, map,
 892                                         m->m_data, m->m_len,
 893                                         segs, maxsegs,
 894                                         NULL, flags, &lastaddr,
 895                                         nsegs, first);
 896                         if (error == ENOMEM && !first) {
 897                                 /*
 898                                  * Out of bounce pages due to too many
 899                                  * fragments in the mbuf chain; return
 900                                  * EFBIG instead.
 901                                  */
 902                                 error = EFBIG;
 903                         }
 904                         first = 0;
 905                 }
 906 #ifdef INVARIANTS
 907                 if (!error)
 908                         KKASSERT(*nsegs <= maxsegs && *nsegs >= 1);
 909 #endif
 910         } else {
 911                 *nsegs = 0;
 912                 error = EINVAL;
 913         }
 914         KKASSERT(error != EINPROGRESS);
 915         return error;
 916 }
 917
 918 /*
 919  * Like _bus_dmamap_load(), but for uios.
 920  */
 921 int
 922 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 923                     struct uio *uio,
 924                     bus_dmamap_callback2_t *callback, void *callback_arg,
 925                     int flags)
 926 {
 927         vm_paddr_t lastaddr;
 928         int nsegs, error, first, i;
 929         bus_size_t resid;
 930         struct iovec *iov;
 931         pmap_t pmap;
 932         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 933         bus_dma_segment_t *segments;
 934         bus_dma_segment_t *segs;
 935         int nsegs_left;
 936
 937         if (dmat->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 938                 segments = cache_segments;
 939         else
 940                 segments = kmalloc(sizeof(bus_dma_segment_t) * dmat->nsegments,
 941                                    M_DEVBUF, M_WAITOK | M_ZERO);
 942
 943         /*
 944          * XXX
 945          * Follow old semantics.  Once all of the callers are fixed,
 946          * we should get rid of these internal flag "adjustment".
 947          */
 948         flags &= ~BUS_DMA_WAITOK;
 949         flags |= BUS_DMA_NOWAIT;
 950
 951         resid = uio->uio_resid;
 952         iov = uio->uio_iov;
 953
 954         segs = segments;
 955         nsegs_left = dmat->nsegments;
 956
 957         if (uio->uio_segflg == UIO_USERSPACE) {
 958                 struct thread *td;
 959
 960                 td = uio->uio_td;
 961                 KASSERT(td != NULL && td->td_proc != NULL,
 962                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 963                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 964         } else {
 965                 pmap = NULL;
 966         }
 967
 968         error = 0;
 969         nsegs = 1;
 970         first = 1;
 971         lastaddr = 0;
 972         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 973                 /*
 974                  * Now at the first iovec to load.  Load each iovec
 975                  * until we have exhausted the residual count.
 976                  */
 977                 bus_size_t minlen =
 978                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 979                 caddr_t addr = (caddr_t) iov[i].iov_base;
 980
 981                 error = _bus_dmamap_load_buffer(dmat, map, addr, minlen,
 982                                 segs, nsegs_left,
 983                                 pmap, flags, &lastaddr, &nsegs, first);
 984                 first = 0;
 985
 986                 resid -= minlen;
 987                 if (error == 0) {
 988                         nsegs_left -= nsegs;
 989                         segs += nsegs;
 990                 }
 991         }
 992
 993         /*
 994          * Minimum one DMA segment, even if 0-length buffer.
 995          */
 996         if (nsegs_left == dmat->nsegments)
 997                 --nsegs_left;
 998
 999         if (error) {
1000                 /* force "no valid mappings" in callback */
1001                 callback(callback_arg, segments, 0, 0, error);
1002         } else {
1003                 callback(callback_arg, segments, dmat->nsegments - nsegs_left,
1004                          uio->uio_resid, error);
1005         }
1006         if (dmat->nsegments > BUS_DMA_CACHE_SEGMENTS)
1007                 kfree(segments, M_DEVBUF);
1008         return error;
1009 }
1010
1011 /*
1012  * Release the mapping held by map.
1013  */
1014 void
1015 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
1016 {
1017         struct bounce_page *bpage;
1018
1019         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1020                 STAILQ_REMOVE_HEAD(&map->bpages, links);
1021                 free_bounce_page(dmat, bpage);
1022         }
1023 }
1024
1025 void
1026 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
1027 {
1028         struct bounce_page *bpage;
1029
1030         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1031                 /*
1032                  * Handle data bouncing.  We might also
1033                  * want to add support for invalidating
1034                  * the caches on broken hardware
1035                  */
1036                 switch (op) {
1037                 case BUS_DMASYNC_PREWRITE:
1038                         while (bpage != NULL) {
1039                                 bcopy((void *)bpage->datavaddr,
1040                                       (void *)bpage->vaddr,
1041                                       bpage->datacount);
1042                                 bpage = STAILQ_NEXT(bpage, links);
1043                         }
1044                         dmat->bounce_zone->total_bounced++;
1045                         break;
1046
1047                 case BUS_DMASYNC_POSTREAD:
1048                         while (bpage != NULL) {
1049                                 bcopy((void *)bpage->vaddr,
1050                                       (void *)bpage->datavaddr,
1051                                       bpage->datacount);
1052                                 bpage = STAILQ_NEXT(bpage, links);
1053                         }
1054                         dmat->bounce_zone->total_bounced++;
1055                         break;
1056
1057                 case BUS_DMASYNC_PREREAD:
1058                 case BUS_DMASYNC_POSTWRITE:
1059                         /* No-ops */
1060                         break;
1061                 }
1062         }
1063 }
1064
1065 static int
1066 alloc_bounce_zone(bus_dma_tag_t dmat)
1067 {
1068         struct bounce_zone *bz, *new_bz;
1069         lwkt_tokref ref;
1070
1071         KASSERT(dmat->bounce_zone == NULL,
1072                 ("bounce zone was already assigned\n"));
1073
1074         new_bz = kmalloc(sizeof(*new_bz), M_DEVBUF, M_INTWAIT | M_ZERO);
1075
1076         lwkt_gettoken(&ref, &bounce_zone_tok);
1077
1078         /* Check to see if we already have a suitable zone */
1079         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1080                 if (dmat->alignment <= bz->alignment &&
1081                     dmat->lowaddr >= bz->lowaddr) {
1082                         lwkt_reltoken(&ref);
1083
1084                         dmat->bounce_zone = bz;
1085                         kfree(new_bz, M_DEVBUF);
1086                         return 0;
1087                 }
1088         }
1089         bz = new_bz;
1090
1091 #ifdef SMP
1092         spin_init(&bz->spin);
1093 #endif
1094         STAILQ_INIT(&bz->bounce_page_list);
1095         STAILQ_INIT(&bz->bounce_map_waitinglist);
1096         bz->free_bpages = 0;
1097         bz->reserved_bpages = 0;
1098         bz->active_bpages = 0;
1099         bz->lowaddr = dmat->lowaddr;
1100         bz->alignment = round_page(dmat->alignment);
1101         ksnprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1102         busdma_zonecount++;
1103         ksnprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1104         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1105
1106         lwkt_reltoken(&ref);
1107
1108         dmat->bounce_zone = bz;
1109
1110         sysctl_ctx_init(&bz->sysctl_ctx);
1111         bz->sysctl_tree = SYSCTL_ADD_NODE(&bz->sysctl_ctx,
1112             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1113             CTLFLAG_RD, 0, "");
1114         if (bz->sysctl_tree == NULL) {
1115                 sysctl_ctx_free(&bz->sysctl_ctx);
1116                 return 0;       /* XXX error code? */
1117         }
1118
1119         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1120             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1121             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1122             "Total bounce pages");
1123         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1124             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1125             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1126             "Free bounce pages");
1127         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1128             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1129             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1130             "Reserved bounce pages");
1131         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1132             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1133             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1134             "Active bounce pages");
1135         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1136             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1137             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1138             "Total bounce requests");
1139         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1140             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1141             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1142             "Total bounce requests that were deferred");
1143         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1144             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1145             "reserve_failed", CTLFLAG_RD, &bz->reserve_failed, 0,
1146             "Total bounce page reservations that were failed");
1147         SYSCTL_ADD_STRING(&bz->sysctl_ctx,
1148             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1149             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1150         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1151             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1152             "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
1153
1154         return 0;
1155 }
1156
1157 static int
1158 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages, int flags)
1159 {
1160         struct bounce_zone *bz = dmat->bounce_zone;
1161         int count = 0, mflags;
1162
1163         if (flags & BUS_DMA_NOWAIT)
1164                 mflags = M_NOWAIT;
1165         else
1166                 mflags = M_WAITOK;
1167
1168         while (numpages > 0) {
1169                 struct bounce_page *bpage;
1170
1171                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
1172
1173                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1174                                                          mflags, 0ul,
1175                                                          bz->lowaddr,
1176                                                          bz->alignment, 0);
1177                 if (bpage->vaddr == 0) {
1178                         kfree(bpage, M_DEVBUF);
1179                         break;
1180                 }
1181                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1182
1183                 BZ_LOCK(bz);
1184                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1185                 total_bounce_pages++;
1186                 bz->total_bpages++;
1187                 bz->free_bpages++;
1188                 BZ_UNLOCK(bz);
1189
1190                 count++;
1191                 numpages--;
1192         }
1193         return count;
1194 }
1195
1196 /* Assume caller holds bounce zone spinlock */
1197 static int
1198 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1199 {
1200         struct bounce_zone *bz = dmat->bounce_zone;
1201         int pages;
1202
1203         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1204         if (!commit && map->pagesneeded > (map->pagesreserved + pages)) {
1205                 bz->reserve_failed++;
1206                 return (map->pagesneeded - (map->pagesreserved + pages));
1207         }
1208
1209         bz->free_bpages -= pages;
1210
1211         bz->reserved_bpages += pages;
1212         KKASSERT(bz->reserved_bpages <= bz->total_bpages);
1213
1214         map->pagesreserved += pages;
1215         pages = map->pagesneeded - map->pagesreserved;
1216
1217         return pages;
1218 }
1219
1220 static void
1221 return_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
1222 {
1223         struct bounce_zone *bz = dmat->bounce_zone;
1224         int reserved = map->pagesreserved;
1225         bus_dmamap_t wait_map;
1226
1227         map->pagesreserved = 0;
1228         map->pagesneeded = 0;
1229
1230         if (reserved == 0)
1231                 return;
1232
1233         BZ_LOCK(bz);
1234
1235         bz->free_bpages += reserved;
1236         KKASSERT(bz->free_bpages <= bz->total_bpages);
1237
1238         KKASSERT(bz->reserved_bpages >= reserved);
1239         bz->reserved_bpages -= reserved;
1240
1241         wait_map = get_map_waiting(dmat);
1242
1243         BZ_UNLOCK(bz);
1244
1245         if (wait_map != NULL)
1246                 add_map_callback(map);
1247 }
1248
1249 static bus_addr_t
1250 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1251                 bus_size_t size)
1252 {
1253         struct bounce_zone *bz = dmat->bounce_zone;
1254         struct bounce_page *bpage;
1255
1256         KASSERT(map->pagesneeded > 0, ("map doesn't need any pages"));
1257         map->pagesneeded--;
1258
1259         KASSERT(map->pagesreserved > 0, ("map doesn't reserve any pages"));
1260         map->pagesreserved--;
1261
1262         BZ_LOCK(bz);
1263
1264         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1265         KASSERT(bpage != NULL, ("free page list is empty"));
1266         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1267
1268         KKASSERT(bz->reserved_bpages > 0);
1269         bz->reserved_bpages--;
1270
1271         bz->active_bpages++;
1272         KKASSERT(bz->active_bpages <= bz->total_bpages);
1273
1274         BZ_UNLOCK(bz);
1275
1276         bpage->datavaddr = vaddr;
1277         bpage->datacount = size;
1278         STAILQ_INSERT_TAIL(&map->bpages, bpage, links);
1279         return bpage->busaddr;
1280 }
1281
1282 static void
1283 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1284 {
1285         struct bounce_zone *bz = dmat->bounce_zone;
1286         bus_dmamap_t map;
1287
1288         bpage->datavaddr = 0;
1289         bpage->datacount = 0;
1290
1291         BZ_LOCK(bz);
1292
1293         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1294
1295         bz->free_bpages++;
1296         KKASSERT(bz->free_bpages <= bz->total_bpages);
1297
1298         KKASSERT(bz->active_bpages > 0);
1299         bz->active_bpages--;
1300
1301         map = get_map_waiting(dmat);
1302
1303         BZ_UNLOCK(bz);
1304
1305         if (map != NULL)
1306                 add_map_callback(map);
1307 }
1308
1309 /* Assume caller holds bounce zone spinlock */
1310 static bus_dmamap_t
1311 get_map_waiting(bus_dma_tag_t dmat)
1312 {
1313         struct bounce_zone *bz = dmat->bounce_zone;
1314         bus_dmamap_t map;
1315
1316         map = STAILQ_FIRST(&bz->bounce_map_waitinglist);
1317         if (map != NULL) {
1318                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1319                         STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
1320                         bz->total_deferred++;
1321                 } else {
1322                         map = NULL;
1323                 }
1324         }
1325         return map;
1326 }
1327
1328 static void
1329 add_map_callback(bus_dmamap_t map)
1330 {
1331         /* XXX callbacklist is not MPSAFE */
1332         crit_enter();
1333         get_mplock();
1334         STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
1335         busdma_swi_pending = 1;
1336         setsoftvm();
1337         rel_mplock();
1338         crit_exit();
1339 }
1340
1341 void
1342 busdma_swi(void)
1343 {
1344         bus_dmamap_t map;
1345
1346         crit_enter();
1347         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1348                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1349                 crit_exit();
1350                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
1351                                 map->callback, map->callback_arg, /*flags*/0);
1352                 crit_enter();
1353         }
1354         crit_exit();
1355 }