sys/platform/pc64/x86_64/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/bus_dma.h>
  36 #include <sys/kernel.h>
  37 #include <sys/sysctl.h>
  38 #include <sys/lock.h>
  39
  40 #include <sys/thread2.h>
  41 #include <sys/spinlock2.h>
  42 #include <sys/mplock2.h>
  43
  44 #include <vm/vm.h>
  45 #include <vm/vm_page.h>
  46
  47 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  48 #include <sys/proc.h>
  49 #include <sys/lock.h>
  50 #include <vm/vm_map.h>
  51
  52 #include <machine/md_var.h>
  53
  54 #define MAX_BPAGES      1024
  55
  56 /*
  57  * 16 x N declared on stack.
  58  */
  59 #define BUS_DMA_CACHE_SEGMENTS  8
  60
  61 struct bounce_zone;
  62 struct bus_dmamap;
  63
  64 struct bus_dma_tag {
  65         bus_dma_tag_t   parent;
  66         bus_size_t      alignment;
  67         bus_size_t      boundary;
  68         bus_addr_t      lowaddr;
  69         bus_addr_t      highaddr;
  70         bus_dma_filter_t *filter;
  71         void            *filterarg;
  72         bus_size_t      maxsize;
  73         u_int           nsegments;
  74         bus_size_t      maxsegsz;
  75         int             flags;
  76         int             ref_count;
  77         int             map_count;
  78         bus_dma_segment_t *segments;
  79         struct bounce_zone *bounce_zone;
  80 #ifdef SMP
  81         struct spinlock spin;
  82 #else
  83         int             unused0;
  84 #endif
  85 };
  86
  87 /*
  88  * bus_dma_tag private flags
  89  */
  90 #define BUS_DMA_BOUNCE_ALIGN    BUS_DMA_BUS2
  91 #define BUS_DMA_BOUNCE_LOWADDR  BUS_DMA_BUS3
  92 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  93
  94 #define BUS_DMA_COULD_BOUNCE    (BUS_DMA_BOUNCE_LOWADDR | BUS_DMA_BOUNCE_ALIGN)
  95
  96 #define BUS_DMAMEM_KMALLOC(dmat) \
  97         ((dmat)->maxsize <= PAGE_SIZE && \
  98          (dmat)->alignment <= PAGE_SIZE && \
  99          (dmat)->lowaddr >= ptoa(Maxmem))
 100
 101 struct bounce_page {
 102         vm_offset_t     vaddr;          /* kva of bounce buffer */
 103         bus_addr_t      busaddr;        /* Physical address */
 104         vm_offset_t     datavaddr;      /* kva of client data */
 105         bus_size_t      datacount;      /* client data count */
 106         STAILQ_ENTRY(bounce_page) links;
 107 };
 108
 109 struct bounce_zone {
 110         STAILQ_ENTRY(bounce_zone) links;
 111         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
 112         STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 113 #ifdef SMP
 114         struct spinlock spin;
 115 #else
 116         int             unused0;
 117 #endif
 118         int             total_bpages;
 119         int             free_bpages;
 120         int             reserved_bpages;
 121         int             active_bpages;
 122         int             total_bounced;
 123         int             total_deferred;
 124         int             reserve_failed;
 125         bus_size_t      alignment;
 126         bus_addr_t      lowaddr;
 127         char            zoneid[8];
 128         char            lowaddrid[20];
 129         struct sysctl_ctx_list sysctl_ctx;
 130         struct sysctl_oid *sysctl_tree;
 131 };
 132
 133 #ifdef SMP
 134 #define BZ_LOCK(bz)     spin_lock_wr(&(bz)->spin)
 135 #define BZ_UNLOCK(bz)   spin_unlock_wr(&(bz)->spin)
 136 #else
 137 #define BZ_LOCK(bz)     crit_enter()
 138 #define BZ_UNLOCK(bz)   crit_exit()
 139 #endif
 140
 141 static struct lwkt_token bounce_zone_tok =
 142         LWKT_TOKEN_INITIALIZER(bounce_zone_tok);
 143 static int busdma_zonecount;
 144 static STAILQ_HEAD(, bounce_zone) bounce_zone_list =
 145         STAILQ_HEAD_INITIALIZER(bounce_zone_list);
 146
 147 int busdma_swi_pending;
 148 static int total_bounce_pages;
 149 static int max_bounce_pages = MAX_BPAGES;
 150 static int bounce_alignment = 1; /* XXX temporary */
 151
 152 TUNABLE_INT("hw.busdma.max_bpages", &max_bounce_pages);
 153 TUNABLE_INT("hw.busdma.bounce_alignment", &bounce_alignment);
 154
 155 struct bus_dmamap {
 156         struct bp_list  bpages;
 157         int             pagesneeded;
 158         int             pagesreserved;
 159         bus_dma_tag_t   dmat;
 160         void            *buf;           /* unmapped buffer pointer */
 161         bus_size_t      buflen;         /* unmapped buffer length */
 162         bus_dmamap_callback_t *callback;
 163         void            *callback_arg;
 164         STAILQ_ENTRY(bus_dmamap) links;
 165 };
 166
 167 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist =
 168         STAILQ_HEAD_INITIALIZER(bounce_map_callbacklist);
 169
 170 static struct bus_dmamap nobounce_dmamap;
 171
 172 static int              alloc_bounce_zone(bus_dma_tag_t);
 173 static int              alloc_bounce_pages(bus_dma_tag_t, u_int, int);
 174 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
 175 static void             return_bounce_pages(bus_dma_tag_t, bus_dmamap_t);
 176 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
 177                             vm_offset_t, bus_size_t);
 178 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
 179
 180 static bus_dmamap_t     get_map_waiting(bus_dma_tag_t);
 181 static void             add_map_callback(bus_dmamap_t);
 182
 183 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 184 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bounce_pages,
 185            0, "Total bounce pages");
 186 SYSCTL_INT(_hw_busdma, OID_AUTO, max_bpages, CTLFLAG_RD, &max_bounce_pages,
 187            0, "Max bounce pages per bounce zone");
 188 SYSCTL_INT(_hw_busdma, OID_AUTO, bounce_alignment, CTLFLAG_RD,
 189            &bounce_alignment, 0, "Obey alignment constraint");
 190
 191 static __inline int
 192 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 193 {
 194         int retval;
 195
 196         retval = 0;
 197         do {
 198                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr) ||
 199                      (bounce_alignment && (paddr & (dmat->alignment - 1)) != 0))
 200                  && (dmat->filter == NULL ||
 201                      dmat->filter(dmat->filterarg, paddr) != 0))
 202                         retval = 1;
 203
 204                 dmat = dmat->parent;
 205         } while (retval == 0 && dmat != NULL);
 206         return (retval);
 207 }
 208
 209 static __inline
 210 bus_dma_segment_t *
 211 bus_dma_tag_lock(bus_dma_tag_t tag, bus_dma_segment_t *cache)
 212 {
 213         if (tag->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 214                 return(cache);
 215 #ifdef SMP
 216         spin_lock_wr(&tag->spin);
 217 #endif
 218         return(tag->segments);
 219 }
 220
 221 static __inline
 222 void
 223 bus_dma_tag_unlock(bus_dma_tag_t tag)
 224 {
 225 #ifdef SMP
 226         if (tag->nsegments > BUS_DMA_CACHE_SEGMENTS)
 227                 spin_unlock_wr(&tag->spin);
 228 #endif
 229 }
 230
 231 /*
 232  * Allocate a device specific dma_tag.
 233  */
 234 int
 235 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 236                    bus_size_t boundary, bus_addr_t lowaddr,
 237                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 238                    void *filterarg, bus_size_t maxsize, int nsegments,
 239                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 240 {
 241         bus_dma_tag_t newtag;
 242         int error = 0;
 243
 244         /*
 245          * Sanity checks
 246          */
 247
 248         if (alignment == 0)
 249                 alignment = 1;
 250         if (alignment & (alignment - 1))
 251                 panic("alignment must be power of 2\n");
 252
 253         if (boundary != 0) {
 254                 if (boundary & (boundary - 1))
 255                         panic("boundary must be power of 2\n");
 256                 if (boundary < maxsegsz) {
 257                         kprintf("boundary < maxsegsz:\n");
 258                         print_backtrace();
 259                         maxsegsz = boundary;
 260                 }
 261         }
 262
 263         /* Return a NULL tag on failure */
 264         *dmat = NULL;
 265
 266         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT | M_ZERO);
 267
 268 #ifdef SMP
 269         spin_init(&newtag->spin);
 270 #endif
 271         newtag->parent = parent;
 272         newtag->alignment = alignment;
 273         newtag->boundary = boundary;
 274         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 275         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 276         newtag->filter = filter;
 277         newtag->filterarg = filterarg;
 278         newtag->maxsize = maxsize;
 279         newtag->nsegments = nsegments;
 280         newtag->maxsegsz = maxsegsz;
 281         newtag->flags = flags;
 282         newtag->ref_count = 1; /* Count ourself */
 283         newtag->map_count = 0;
 284         newtag->segments = NULL;
 285         newtag->bounce_zone = NULL;
 286
 287         /* Take into account any restrictions imposed by our parent tag */
 288         if (parent != NULL) {
 289                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 290                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 291
 292                 if (newtag->boundary == 0) {
 293                         newtag->boundary = parent->boundary;
 294                 } else if (parent->boundary != 0) {
 295                         newtag->boundary = MIN(parent->boundary,
 296                                                newtag->boundary);
 297                 }
 298
 299 #ifdef notyet
 300                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
 301 #endif
 302
 303                 if (newtag->filter == NULL) {
 304                         /*
 305                          * Short circuit looking at our parent directly
 306                          * since we have encapsulated all of its information
 307                          */
 308                         newtag->filter = parent->filter;
 309                         newtag->filterarg = parent->filterarg;
 310                         newtag->parent = parent->parent;
 311                 }
 312                 if (newtag->parent != NULL)
 313                         parent->ref_count++;
 314         }
 315
 316         if (newtag->lowaddr < ptoa(Maxmem))
 317                 newtag->flags |= BUS_DMA_BOUNCE_LOWADDR;
 318         if (bounce_alignment && newtag->alignment > 1 &&
 319             !(newtag->flags & BUS_DMA_ALIGNED))
 320                 newtag->flags |= BUS_DMA_BOUNCE_ALIGN;
 321
 322         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
 323             (flags & BUS_DMA_ALLOCNOW) != 0) {
 324                 struct bounce_zone *bz;
 325
 326                 /* Must bounce */
 327
 328                 error = alloc_bounce_zone(newtag);
 329                 if (error)
 330                         goto back;
 331                 bz = newtag->bounce_zone;
 332
 333                 if (ptoa(bz->total_bpages) < maxsize) {
 334                         int pages;
 335
 336                         if (flags & BUS_DMA_ONEBPAGE) {
 337                                 pages = 1;
 338                         } else {
 339                                 pages = atop(round_page(maxsize)) -
 340                                         bz->total_bpages;
 341                                 pages = MAX(pages, 1);
 342                         }
 343
 344                         /* Add pages to our bounce pool */
 345                         if (alloc_bounce_pages(newtag, pages, flags) < pages)
 346                                 error = ENOMEM;
 347
 348                         /* Performed initial allocation */
 349                         newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 350                 }
 351         }
 352 back:
 353         if (error)
 354                 kfree(newtag, M_DEVBUF);
 355         else
 356                 *dmat = newtag;
 357         return error;
 358 }
 359
 360 int
 361 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 362 {
 363         if (dmat != NULL) {
 364                 if (dmat->map_count != 0)
 365                         return (EBUSY);
 366
 367                 while (dmat != NULL) {
 368                         bus_dma_tag_t parent;
 369
 370                         parent = dmat->parent;
 371                         dmat->ref_count--;
 372                         if (dmat->ref_count == 0) {
 373                                 if (dmat->segments != NULL)
 374                                         kfree(dmat->segments, M_DEVBUF);
 375                                 kfree(dmat, M_DEVBUF);
 376                                 /*
 377                                  * Last reference count, so
 378                                  * release our reference
 379                                  * count on our parent.
 380                                  */
 381                                 dmat = parent;
 382                         } else
 383                                 dmat = NULL;
 384                 }
 385         }
 386         return (0);
 387 }
 388
 389 bus_size_t
 390 bus_dma_tag_getmaxsize(bus_dma_tag_t tag)
 391 {
 392         return(tag->maxsize);
 393 }
 394
 395 /*
 396  * Allocate a handle for mapping from kva/uva/physical
 397  * address space into bus device space.
 398  */
 399 int
 400 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 401 {
 402         int error;
 403
 404         error = 0;
 405
 406         if (dmat->segments == NULL) {
 407                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 408                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 409                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 410         }
 411
 412         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 413                 struct bounce_zone *bz;
 414                 int maxpages;
 415
 416                 /* Must bounce */
 417
 418                 if (dmat->bounce_zone == NULL) {
 419                         error = alloc_bounce_zone(dmat);
 420                         if (error)
 421                                 return error;
 422                 }
 423                 bz = dmat->bounce_zone;
 424
 425                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
 426
 427                 /* Initialize the new map */
 428                 STAILQ_INIT(&((*mapp)->bpages));
 429
 430                 /*
 431                  * Attempt to add pages to our pool on a per-instance
 432                  * basis up to a sane limit.
 433                  */
 434                 if (dmat->flags & BUS_DMA_BOUNCE_ALIGN) {
 435                         maxpages = max_bounce_pages;
 436                 } else {
 437                         maxpages = MIN(max_bounce_pages,
 438                                        Maxmem - atop(dmat->lowaddr));
 439                 }
 440                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 441                  || (dmat->map_count > 0
 442                   && bz->total_bpages < maxpages)) {
 443                         int pages;
 444
 445                         if (flags & BUS_DMA_ONEBPAGE) {
 446                                 pages = 1;
 447                         } else {
 448                                 pages = atop(round_page(dmat->maxsize));
 449                                 pages = MIN(maxpages - bz->total_bpages, pages);
 450                                 pages = MAX(pages, 1);
 451                         }
 452                         if (alloc_bounce_pages(dmat, pages, flags) < pages)
 453                                 error = ENOMEM;
 454
 455                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 456                                 if (!error)
 457                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 458                         } else {
 459                                 error = 0;
 460                         }
 461                 }
 462         } else {
 463                 *mapp = NULL;
 464         }
 465         if (!error)
 466                 dmat->map_count++;
 467         return error;
 468 }
 469
 470 /*
 471  * Destroy a handle for mapping from kva/uva/physical
 472  * address space into bus device space.
 473  */
 474 int
 475 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 476 {
 477         if (map != NULL) {
 478                 if (STAILQ_FIRST(&map->bpages) != NULL)
 479                         return (EBUSY);
 480                 kfree(map, M_DEVBUF);
 481         }
 482         dmat->map_count--;
 483         return (0);
 484 }
 485
 486 static __inline bus_size_t
 487 check_kmalloc(bus_dma_tag_t dmat, const void *vaddr0, int verify)
 488 {
 489         bus_size_t maxsize = 0;
 490         uintptr_t vaddr = (uintptr_t)vaddr0;
 491
 492         if ((vaddr ^ (vaddr + dmat->maxsize - 1)) & ~PAGE_MASK) {
 493                 if (verify || bootverbose)
 494                         kprintf("boundary check failed\n");
 495                 if (verify)
 496                         print_backtrace(); /* XXX panic */
 497                 maxsize = dmat->maxsize;
 498         }
 499         if (vaddr & (dmat->alignment - 1)) {
 500                 if (verify || bootverbose)
 501                         kprintf("alignment check failed\n");
 502                 if (verify)
 503                         print_backtrace(); /* XXX panic */
 504                 if (dmat->maxsize < dmat->alignment)
 505                         maxsize = dmat->alignment;
 506                 else
 507                         maxsize = dmat->maxsize;
 508         }
 509         return maxsize;
 510 }
 511
 512 /*
 513  * Allocate a piece of memory that can be efficiently mapped into
 514  * bus device space based on the constraints lited in the dma tag.
 515  *
 516  * mapp is degenerate.  By definition this allocation should not require
 517  * bounce buffers so do not allocate a dma map.
 518  */
 519 int
 520 bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr, int flags,
 521                  bus_dmamap_t *mapp)
 522 {
 523         int mflags;
 524
 525         /* If we succeed, no mapping/bouncing will be required */
 526         *mapp = NULL;
 527
 528         if (dmat->segments == NULL) {
 529                 KKASSERT(dmat->nsegments < 16384);
 530                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 531                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 532         }
 533
 534         if (flags & BUS_DMA_NOWAIT)
 535                 mflags = M_NOWAIT;
 536         else
 537                 mflags = M_WAITOK;
 538         if (flags & BUS_DMA_ZERO)
 539                 mflags |= M_ZERO;
 540
 541         if (BUS_DMAMEM_KMALLOC(dmat)) {
 542                 bus_size_t maxsize;
 543
 544                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 545
 546                 /*
 547                  * XXX
 548                  * Check whether the allocation
 549                  * - crossed a page boundary
 550                  * - was not aligned
 551                  * Retry with power-of-2 alignment in the above cases.
 552                  */
 553                 maxsize = check_kmalloc(dmat, *vaddr, 0);
 554                 if (maxsize) {
 555                         size_t size;
 556
 557                         kfree(*vaddr, M_DEVBUF);
 558                         /* XXX check for overflow? */
 559                         for (size = 1; size <= maxsize; size <<= 1)
 560                                 ;
 561                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 562                         check_kmalloc(dmat, *vaddr, 1);
 563                 }
 564         } else {
 565                 /*
 566                  * XXX Use Contigmalloc until it is merged into this facility
 567                  *     and handles multi-seg allocations.  Nobody is doing
 568                  *     multi-seg allocations yet though.
 569                  */
 570                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 571                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
 572         }
 573         if (*vaddr == NULL)
 574                 return (ENOMEM);
 575         return (0);
 576 }
 577
 578 /*
 579  * Free a piece of memory and it's allociated dmamap, that was allocated
 580  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 581  */
 582 void
 583 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 584 {
 585         /*
 586          * dmamem does not need to be bounced, so the map should be
 587          * NULL
 588          */
 589         if (map != NULL)
 590                 panic("bus_dmamem_free: Invalid map freed\n");
 591         if (BUS_DMAMEM_KMALLOC(dmat))
 592                 kfree(vaddr, M_DEVBUF);
 593         else
 594                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 595 }
 596
 597 static __inline vm_paddr_t
 598 _bus_dma_extract(pmap_t pmap, vm_offset_t vaddr)
 599 {
 600         if (pmap)
 601                 return pmap_extract(pmap, vaddr);
 602         else
 603                 return pmap_kextract(vaddr);
 604 }
 605
 606 /*
 607  * Utility function to load a linear buffer.  lastaddrp holds state
 608  * between invocations (for multiple-buffer loads).  segp contains
 609  * the segment following the starting one on entrace, and the ending
 610  * segment on exit.  first indicates if this is the first invocation
 611  * of this function.
 612  */
 613 static int
 614 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 615                         bus_dmamap_t map,
 616                         void *buf, bus_size_t buflen,
 617                         bus_dma_segment_t *segments,
 618                         int nsegments,
 619                         pmap_t pmap,
 620                         int flags,
 621                         vm_paddr_t *lastpaddrp,
 622                         int *segp,
 623                         int first)
 624 {
 625         vm_offset_t vaddr;
 626         vm_paddr_t paddr, nextpaddr;
 627         bus_dma_segment_t *sg;
 628         bus_addr_t bmask;
 629         int seg, error = 0;
 630
 631         if (map == NULL)
 632                 map = &nobounce_dmamap;
 633
 634 #ifdef INVARIANTS
 635         if (dmat->flags & BUS_DMA_ALIGNED)
 636                 KKASSERT(((uintptr_t)buf & (dmat->alignment - 1)) == 0);
 637 #endif
 638
 639         /*
 640          * If we are being called during a callback, pagesneeded will
 641          * be non-zero, so we can avoid doing the work twice.
 642          */
 643         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 644             map != &nobounce_dmamap && map->pagesneeded == 0) {
 645                 vm_offset_t vendaddr;
 646
 647                 /*
 648                  * Count the number of bounce pages
 649                  * needed in order to complete this transfer
 650                  */
 651                 vaddr = (vm_offset_t)buf;
 652                 vendaddr = (vm_offset_t)buf + buflen;
 653
 654                 while (vaddr < vendaddr) {
 655                         paddr = _bus_dma_extract(pmap, vaddr);
 656                         if (run_filter(dmat, paddr) != 0)
 657                                 map->pagesneeded++;
 658                         vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
 659                 }
 660         }
 661
 662         /* Reserve Necessary Bounce Pages */
 663         if (map->pagesneeded != 0) {
 664                 struct bounce_zone *bz;
 665
 666                 bz = dmat->bounce_zone;
 667                 BZ_LOCK(bz);
 668                 if (flags & BUS_DMA_NOWAIT) {
 669                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
 670                                 BZ_UNLOCK(bz);
 671                                 error = ENOMEM;
 672                                 goto free_bounce;
 673                         }
 674                 } else {
 675                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
 676                                 /* Queue us for resources */
 677                                 map->dmat = dmat;
 678                                 map->buf = buf;
 679                                 map->buflen = buflen;
 680
 681                                 STAILQ_INSERT_TAIL(
 682                                     &dmat->bounce_zone->bounce_map_waitinglist,
 683                                     map, links);
 684                                 BZ_UNLOCK(bz);
 685
 686                                 return (EINPROGRESS);
 687                         }
 688                 }
 689                 BZ_UNLOCK(bz);
 690         }
 691
 692         KKASSERT(*segp >= 1 && *segp <= nsegments);
 693         seg = *segp;
 694         sg = &segments[seg - 1];
 695
 696         vaddr = (vm_offset_t)buf;
 697         nextpaddr = *lastpaddrp;
 698         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 699
 700         /* force at least one segment */
 701         do {
 702                 bus_size_t size;
 703
 704                 /*
 705                  * Per-page main loop
 706                  */
 707                 paddr = _bus_dma_extract(pmap, vaddr);
 708                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 709                 if (size > buflen)
 710                         size = buflen;
 711                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 712                         /*
 713                          * note: this paddr has the same in-page offset
 714                          * as vaddr and thus the paddr above, so the
 715                          * size does not have to be recalculated
 716                          */
 717                         paddr = add_bounce_page(dmat, map, vaddr, size);
 718                 }
 719
 720                 /*
 721                  * Fill in the bus_dma_segment
 722                  */
 723                 if (first) {
 724                         sg->ds_addr = paddr;
 725                         sg->ds_len = size;
 726                         first = 0;
 727                 } else if (paddr == nextpaddr) {
 728                         sg->ds_len += size;
 729                 } else {
 730                         sg++;
 731                         seg++;
 732                         if (seg > nsegments)
 733                                 break;
 734                         sg->ds_addr = paddr;
 735                         sg->ds_len = size;
 736                 }
 737                 nextpaddr = paddr + size;
 738
 739                 /*
 740                  * Handle maxsegsz and boundary issues with a nested loop
 741                  */
 742                 for (;;) {
 743                         bus_size_t tmpsize;
 744
 745                         /*
 746                          * Limit to the boundary and maximum segment size
 747                          */
 748                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 749                                 tmpsize = dmat->boundary -
 750                                           (sg->ds_addr & ~bmask);
 751                                 if (tmpsize > dmat->maxsegsz)
 752                                         tmpsize = dmat->maxsegsz;
 753                                 KKASSERT(tmpsize < sg->ds_len);
 754                         } else if (sg->ds_len > dmat->maxsegsz) {
 755                                 tmpsize = dmat->maxsegsz;
 756                         } else {
 757                                 break;
 758                         }
 759
 760                         /*
 761                          * Futz, split the data into a new segment.
 762                          */
 763                         if (seg >= nsegments)
 764                                 goto fail;
 765                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 766                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 767                         sg[0].ds_len = tmpsize;
 768                         sg++;
 769                         seg++;
 770                 }
 771
 772                 /*
 773                  * Adjust for loop
 774                  */
 775                 buflen -= size;
 776                 vaddr += size;
 777         } while (buflen > 0);
 778 fail:
 779         if (buflen != 0)
 780                 error = EFBIG;
 781
 782         *segp = seg;
 783         *lastpaddrp = nextpaddr;
 784
 785 free_bounce:
 786         if (error && (dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 787             map != &nobounce_dmamap) {
 788                 _bus_dmamap_unload(dmat, map);
 789                 return_bounce_pages(dmat, map);
 790         }
 791         return error;
 792 }
 793
 794 /*
 795  * Map the buffer buf into bus space using the dmamap map.
 796  */
 797 int
 798 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 799                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 800                 void *callback_arg, int flags)
 801 {
 802         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 803         bus_dma_segment_t *segments;
 804         vm_paddr_t lastaddr = 0;
 805         int error, nsegs = 1;
 806
 807         if (map != NULL) {
 808                 /*
 809                  * XXX
 810                  * Follow old semantics.  Once all of the callers are fixed,
 811                  * we should get rid of these internal flag "adjustment".
 812                  */
 813                 flags &= ~BUS_DMA_NOWAIT;
 814                 flags |= BUS_DMA_WAITOK;
 815
 816                 map->callback = callback;
 817                 map->callback_arg = callback_arg;
 818         }
 819
 820         segments = bus_dma_tag_lock(dmat, cache_segments);
 821         error = _bus_dmamap_load_buffer(dmat, map, buf, buflen,
 822                         segments, dmat->nsegments,
 823                         NULL, flags, &lastaddr, &nsegs, 1);
 824         if (error == EINPROGRESS) {
 825                 bus_dma_tag_unlock(dmat);
 826                 return error;
 827         }
 828         callback(callback_arg, segments, nsegs, error);
 829         bus_dma_tag_unlock(dmat);
 830         return 0;
 831 }
 832
 833 /*
 834  * Like _bus_dmamap_load(), but for mbufs.
 835  */
 836 int
 837 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 838                      struct mbuf *m0,
 839                      bus_dmamap_callback2_t *callback, void *callback_arg,
 840                      int flags)
 841 {
 842         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 843         bus_dma_segment_t *segments;
 844         int nsegs, error;
 845
 846         /*
 847          * XXX
 848          * Follow old semantics.  Once all of the callers are fixed,
 849          * we should get rid of these internal flag "adjustment".
 850          */
 851         flags &= ~BUS_DMA_WAITOK;
 852         flags |= BUS_DMA_NOWAIT;
 853
 854         segments = bus_dma_tag_lock(dmat, cache_segments);
 855         error = bus_dmamap_load_mbuf_segment(dmat, map, m0,
 856                         segments, dmat->nsegments, &nsegs, flags);
 857         if (error) {
 858                 /* force "no valid mappings" in callback */
 859                 callback(callback_arg, segments, 0,
 860                          0, error);
 861         } else {
 862                 callback(callback_arg, segments, nsegs,
 863                          m0->m_pkthdr.len, error);
 864         }
 865         bus_dma_tag_unlock(dmat);
 866         return error;
 867 }
 868
 869 int
 870 bus_dmamap_load_mbuf_segment(bus_dma_tag_t dmat, bus_dmamap_t map,
 871                              struct mbuf *m0,
 872                              bus_dma_segment_t *segs, int maxsegs,
 873                              int *nsegs, int flags)
 874 {
 875         int error;
 876
 877         M_ASSERTPKTHDR(m0);
 878
 879         KASSERT(maxsegs >= 1, ("invalid maxsegs %d\n", maxsegs));
 880         KASSERT(maxsegs <= dmat->nsegments,
 881                 ("%d too many segments, dmat only support %d segments\n",
 882                  maxsegs, dmat->nsegments));
 883         KASSERT(flags & BUS_DMA_NOWAIT,
 884                 ("only BUS_DMA_NOWAIT is supported\n"));
 885
 886         if (m0->m_pkthdr.len <= dmat->maxsize) {
 887                 int first = 1;
 888                 vm_paddr_t lastaddr = 0;
 889                 struct mbuf *m;
 890
 891                 *nsegs = 1;
 892                 error = 0;
 893                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 894                         if (m->m_len == 0)
 895                                 continue;
 896
 897                         error = _bus_dmamap_load_buffer(dmat, map,
 898                                         m->m_data, m->m_len,
 899                                         segs, maxsegs,
 900                                         NULL, flags, &lastaddr,
 901                                         nsegs, first);
 902                         if (error == ENOMEM && !first) {
 903                                 /*
 904                                  * Out of bounce pages due to too many
 905                                  * fragments in the mbuf chain; return
 906                                  * EFBIG instead.
 907                                  */
 908                                 error = EFBIG;
 909                         }
 910                         first = 0;
 911                 }
 912 #ifdef INVARIANTS
 913                 if (!error)
 914                         KKASSERT(*nsegs <= maxsegs && *nsegs >= 1);
 915 #endif
 916         } else {
 917                 *nsegs = 0;
 918                 error = EINVAL;
 919         }
 920         KKASSERT(error != EINPROGRESS);
 921         return error;
 922 }
 923
 924 /*
 925  * Like _bus_dmamap_load(), but for uios.
 926  */
 927 int
 928 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 929                     struct uio *uio,
 930                     bus_dmamap_callback2_t *callback, void *callback_arg,
 931                     int flags)
 932 {
 933         vm_paddr_t lastaddr;
 934         int nsegs, error, first, i;
 935         bus_size_t resid;
 936         struct iovec *iov;
 937         pmap_t pmap;
 938         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 939         bus_dma_segment_t *segments;
 940         bus_dma_segment_t *segs;
 941         int nsegs_left;
 942
 943         if (dmat->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 944                 segments = cache_segments;
 945         else
 946                 segments = kmalloc(sizeof(bus_dma_segment_t) * dmat->nsegments,
 947                                    M_DEVBUF, M_WAITOK | M_ZERO);
 948
 949         /*
 950          * XXX
 951          * Follow old semantics.  Once all of the callers are fixed,
 952          * we should get rid of these internal flag "adjustment".
 953          */
 954         flags &= ~BUS_DMA_WAITOK;
 955         flags |= BUS_DMA_NOWAIT;
 956
 957         resid = (bus_size_t)uio->uio_resid;
 958         iov = uio->uio_iov;
 959
 960         segs = segments;
 961         nsegs_left = dmat->nsegments;
 962
 963         if (uio->uio_segflg == UIO_USERSPACE) {
 964                 struct thread *td;
 965
 966                 td = uio->uio_td;
 967                 KASSERT(td != NULL && td->td_proc != NULL,
 968                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 969                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 970         } else {
 971                 pmap = NULL;
 972         }
 973
 974         error = 0;
 975         nsegs = 1;
 976         first = 1;
 977         lastaddr = 0;
 978         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 979                 /*
 980                  * Now at the first iovec to load.  Load each iovec
 981                  * until we have exhausted the residual count.
 982                  */
 983                 bus_size_t minlen =
 984                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 985                 caddr_t addr = (caddr_t) iov[i].iov_base;
 986
 987                 error = _bus_dmamap_load_buffer(dmat, map, addr, minlen,
 988                                 segs, nsegs_left,
 989                                 pmap, flags, &lastaddr, &nsegs, first);
 990                 first = 0;
 991
 992                 resid -= minlen;
 993                 if (error == 0) {
 994                         nsegs_left -= nsegs;
 995                         segs += nsegs;
 996                 }
 997         }
 998
 999         /*
1000          * Minimum one DMA segment, even if 0-length buffer.
1001          */
1002         if (nsegs_left == dmat->nsegments)
1003                 --nsegs_left;
1004
1005         if (error) {
1006                 /* force "no valid mappings" in callback */
1007                 callback(callback_arg, segments, 0,
1008                          0, error);
1009         } else {
1010                 callback(callback_arg, segments, dmat->nsegments - nsegs_left,
1011                          (bus_size_t)uio->uio_resid, error);
1012         }
1013         if (dmat->nsegments > BUS_DMA_CACHE_SEGMENTS)
1014                 kfree(segments, M_DEVBUF);
1015         return error;
1016 }
1017
1018 /*
1019  * Release the mapping held by map.
1020  */
1021 void
1022 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
1023 {
1024         struct bounce_page *bpage;
1025
1026         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1027                 STAILQ_REMOVE_HEAD(&map->bpages, links);
1028                 free_bounce_page(dmat, bpage);
1029         }
1030 }
1031
1032 void
1033 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
1034 {
1035         struct bounce_page *bpage;
1036
1037         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1038                 /*
1039                  * Handle data bouncing.  We might also
1040                  * want to add support for invalidating
1041                  * the caches on broken hardware
1042                  */
1043                 switch (op) {
1044                 case BUS_DMASYNC_PREWRITE:
1045                         while (bpage != NULL) {
1046                                 bcopy((void *)bpage->datavaddr,
1047                                       (void *)bpage->vaddr,
1048                                       bpage->datacount);
1049                                 bpage = STAILQ_NEXT(bpage, links);
1050                         }
1051                         dmat->bounce_zone->total_bounced++;
1052                         break;
1053
1054                 case BUS_DMASYNC_POSTREAD:
1055                         while (bpage != NULL) {
1056                                 bcopy((void *)bpage->vaddr,
1057                                       (void *)bpage->datavaddr,
1058                                       bpage->datacount);
1059                                 bpage = STAILQ_NEXT(bpage, links);
1060                         }
1061                         dmat->bounce_zone->total_bounced++;
1062                         break;
1063
1064                 case BUS_DMASYNC_PREREAD:
1065                 case BUS_DMASYNC_POSTWRITE:
1066                         /* No-ops */
1067                         break;
1068                 }
1069         }
1070 }
1071
1072 static int
1073 alloc_bounce_zone(bus_dma_tag_t dmat)
1074 {
1075         struct bounce_zone *bz, *new_bz;
1076         lwkt_tokref ref;
1077
1078         KASSERT(dmat->bounce_zone == NULL,
1079                 ("bounce zone was already assigned\n"));
1080
1081         new_bz = kmalloc(sizeof(*new_bz), M_DEVBUF, M_INTWAIT | M_ZERO);
1082
1083         lwkt_gettoken(&ref, &bounce_zone_tok);
1084
1085         /* Check to see if we already have a suitable zone */
1086         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1087                 if (dmat->alignment <= bz->alignment &&
1088                     dmat->lowaddr >= bz->lowaddr) {
1089                         lwkt_reltoken(&ref);
1090
1091                         dmat->bounce_zone = bz;
1092                         kfree(new_bz, M_DEVBUF);
1093                         return 0;
1094                 }
1095         }
1096         bz = new_bz;
1097
1098 #ifdef SMP
1099         spin_init(&bz->spin);
1100 #endif
1101         STAILQ_INIT(&bz->bounce_page_list);
1102         STAILQ_INIT(&bz->bounce_map_waitinglist);
1103         bz->free_bpages = 0;
1104         bz->reserved_bpages = 0;
1105         bz->active_bpages = 0;
1106         bz->lowaddr = dmat->lowaddr;
1107         bz->alignment = round_page(dmat->alignment);
1108         ksnprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1109         busdma_zonecount++;
1110         ksnprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1111         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1112
1113         lwkt_reltoken(&ref);
1114
1115         dmat->bounce_zone = bz;
1116
1117         sysctl_ctx_init(&bz->sysctl_ctx);
1118         bz->sysctl_tree = SYSCTL_ADD_NODE(&bz->sysctl_ctx,
1119             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1120             CTLFLAG_RD, 0, "");
1121         if (bz->sysctl_tree == NULL) {
1122                 sysctl_ctx_free(&bz->sysctl_ctx);
1123                 return 0;       /* XXX error code? */
1124         }
1125
1126         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1127             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1128             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1129             "Total bounce pages");
1130         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1131             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1132             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1133             "Free bounce pages");
1134         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1135             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1136             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1137             "Reserved bounce pages");
1138         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1139             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1140             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1141             "Active bounce pages");
1142         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1143             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1144             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1145             "Total bounce requests");
1146         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1147             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1148             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1149             "Total bounce requests that were deferred");
1150         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1151             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1152             "reserve_failed", CTLFLAG_RD, &bz->reserve_failed, 0,
1153             "Total bounce page reservations that were failed");
1154         SYSCTL_ADD_STRING(&bz->sysctl_ctx,
1155             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1156             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1157         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1158             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1159             "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
1160
1161         return 0;
1162 }
1163
1164 static int
1165 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages, int flags)
1166 {
1167         struct bounce_zone *bz = dmat->bounce_zone;
1168         int count = 0, mflags;
1169
1170         if (flags & BUS_DMA_NOWAIT)
1171                 mflags = M_NOWAIT;
1172         else
1173                 mflags = M_WAITOK;
1174
1175         while (numpages > 0) {
1176                 struct bounce_page *bpage;
1177
1178                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
1179
1180                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1181                                                          mflags, 0ul,
1182                                                          bz->lowaddr,
1183                                                          bz->alignment, 0);
1184                 if (bpage->vaddr == 0) {
1185                         kfree(bpage, M_DEVBUF);
1186                         break;
1187                 }
1188                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1189
1190                 BZ_LOCK(bz);
1191                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1192                 total_bounce_pages++;
1193                 bz->total_bpages++;
1194                 bz->free_bpages++;
1195                 BZ_UNLOCK(bz);
1196
1197                 count++;
1198                 numpages--;
1199         }
1200         return count;
1201 }
1202
1203 /* Assume caller holds bounce zone spinlock */
1204 static int
1205 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1206 {
1207         struct bounce_zone *bz = dmat->bounce_zone;
1208         int pages;
1209
1210         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1211         if (!commit && map->pagesneeded > (map->pagesreserved + pages)) {
1212                 bz->reserve_failed++;
1213                 return (map->pagesneeded - (map->pagesreserved + pages));
1214         }
1215
1216         bz->free_bpages -= pages;
1217
1218         bz->reserved_bpages += pages;
1219         KKASSERT(bz->reserved_bpages <= bz->total_bpages);
1220
1221         map->pagesreserved += pages;
1222         pages = map->pagesneeded - map->pagesreserved;
1223
1224         return pages;
1225 }
1226
1227 static void
1228 return_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
1229 {
1230         struct bounce_zone *bz = dmat->bounce_zone;
1231         int reserved = map->pagesreserved;
1232         bus_dmamap_t wait_map;
1233
1234         map->pagesreserved = 0;
1235         map->pagesneeded = 0;
1236
1237         if (reserved == 0)
1238                 return;
1239
1240         BZ_LOCK(bz);
1241
1242         bz->free_bpages += reserved;
1243         KKASSERT(bz->free_bpages <= bz->total_bpages);
1244
1245         KKASSERT(bz->reserved_bpages >= reserved);
1246         bz->reserved_bpages -= reserved;
1247
1248         wait_map = get_map_waiting(dmat);
1249
1250         BZ_UNLOCK(bz);
1251
1252         if (wait_map != NULL)
1253                 add_map_callback(map);
1254 }
1255
1256 static bus_addr_t
1257 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1258                 bus_size_t size)
1259 {
1260         struct bounce_zone *bz = dmat->bounce_zone;
1261         struct bounce_page *bpage;
1262
1263         KASSERT(map->pagesneeded > 0, ("map doesn't need any pages"));
1264         map->pagesneeded--;
1265
1266         KASSERT(map->pagesreserved > 0, ("map doesn't reserve any pages"));
1267         map->pagesreserved--;
1268
1269         BZ_LOCK(bz);
1270
1271         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1272         KASSERT(bpage != NULL, ("free page list is empty"));
1273         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1274
1275         KKASSERT(bz->reserved_bpages > 0);
1276         bz->reserved_bpages--;
1277
1278         bz->active_bpages++;
1279         KKASSERT(bz->active_bpages <= bz->total_bpages);
1280
1281         BZ_UNLOCK(bz);
1282
1283         bpage->datavaddr = vaddr;
1284         bpage->datacount = size;
1285         STAILQ_INSERT_TAIL(&map->bpages, bpage, links);
1286         return bpage->busaddr;
1287 }
1288
1289 static void
1290 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1291 {
1292         struct bounce_zone *bz = dmat->bounce_zone;
1293         bus_dmamap_t map;
1294
1295         bpage->datavaddr = 0;
1296         bpage->datacount = 0;
1297
1298         BZ_LOCK(bz);
1299
1300         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1301
1302         bz->free_bpages++;
1303         KKASSERT(bz->free_bpages <= bz->total_bpages);
1304
1305         KKASSERT(bz->active_bpages > 0);
1306         bz->active_bpages--;
1307
1308         map = get_map_waiting(dmat);
1309
1310         BZ_UNLOCK(bz);
1311
1312         if (map != NULL)
1313                 add_map_callback(map);
1314 }
1315
1316 /* Assume caller holds bounce zone spinlock */
1317 static bus_dmamap_t
1318 get_map_waiting(bus_dma_tag_t dmat)
1319 {
1320         struct bounce_zone *bz = dmat->bounce_zone;
1321         bus_dmamap_t map;
1322
1323         map = STAILQ_FIRST(&bz->bounce_map_waitinglist);
1324         if (map != NULL) {
1325                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1326                         STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
1327                         bz->total_deferred++;
1328                 } else {
1329                         map = NULL;
1330                 }
1331         }
1332         return map;
1333 }
1334
1335 static void
1336 add_map_callback(bus_dmamap_t map)
1337 {
1338         /* XXX callbacklist is not MPSAFE */
1339         crit_enter();
1340         get_mplock();
1341         STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
1342         busdma_swi_pending = 1;
1343         setsoftvm();
1344         rel_mplock();
1345         crit_exit();
1346 }
1347
1348 void
1349 busdma_swi(void)
1350 {
1351         bus_dmamap_t map;
1352
1353         crit_enter();
1354         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1355                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1356                 crit_exit();
1357                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
1358                                 map->callback, map->callback_arg, /*flags*/0);
1359                 crit_enter();
1360         }
1361         crit_exit();
1362 }