sys/x86/x86/busdma_bounce.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
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/malloc.h>
  33 #include <sys/bus.h>
  34 #include <sys/interrupt.h>
  35 #include <sys/kernel.h>
  36 #include <sys/ktr.h>
  37 #include <sys/lock.h>
  38 #include <sys/proc.h>
  39 #include <sys/memdesc.h>
  40 #include <sys/mutex.h>
  41 #include <sys/sysctl.h>
  42 #include <sys/uio.h>
  43
  44 #include <vm/vm.h>
  45 #include <vm/vm_extern.h>
  46 #include <vm/vm_kern.h>
  47 #include <vm/vm_page.h>
  48 #include <vm/vm_map.h>
  49
  50 #include <machine/atomic.h>
  51 #include <machine/bus.h>
  52 #include <machine/md_var.h>
  53 #include <machine/specialreg.h>
  54 #include <x86/include/busdma_impl.h>
  55
  56 #ifdef __i386__
  57 #define MAX_BPAGES 512
  58 #else
  59 #define MAX_BPAGES 8192
  60 #endif
  61
  62 enum {
  63         BUS_DMA_COULD_BOUNCE    = 0x01,
  64         BUS_DMA_MIN_ALLOC_COMP  = 0x02,
  65         BUS_DMA_KMEM_ALLOC      = 0x04,
  66 };
  67
  68 struct bounce_zone;
  69
  70 struct bus_dma_tag {
  71         struct bus_dma_tag_common common;
  72         int                     map_count;
  73         int                     bounce_flags;
  74         bus_dma_segment_t       *segments;
  75         struct bounce_zone      *bounce_zone;
  76 };
  77
  78 struct bounce_page {
  79         vm_offset_t     vaddr;          /* kva of bounce buffer */
  80         bus_addr_t      busaddr;        /* Physical address */
  81         vm_offset_t     datavaddr;      /* kva of client data */
  82         vm_offset_t     dataoffs;       /* page offset of client data */
  83         vm_page_t       datapage[2];    /* physical page(s) of client data */
  84         bus_size_t      datacount;      /* client data count */
  85         STAILQ_ENTRY(bounce_page) links;
  86 };
  87
  88 int busdma_swi_pending;
  89
  90 struct bounce_zone {
  91         STAILQ_ENTRY(bounce_zone) links;
  92         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  93         int             total_bpages;
  94         int             free_bpages;
  95         int             reserved_bpages;
  96         int             active_bpages;
  97         int             total_bounced;
  98         int             total_deferred;
  99         int             map_count;
 100         bus_size_t      alignment;
 101         bus_addr_t      lowaddr;
 102         char            zoneid[8];
 103         char            lowaddrid[20];
 104         struct sysctl_ctx_list sysctl_tree;
 105         struct sysctl_oid *sysctl_tree_top;
 106 };
 107
 108 static struct mtx bounce_lock;
 109 static int total_bpages;
 110 static int busdma_zonecount;
 111 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
 112
 113 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 114 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
 115            "Total bounce pages");
 116
 117 struct bus_dmamap {
 118         struct bp_list         bpages;
 119         int                    pagesneeded;
 120         int                    pagesreserved;
 121         bus_dma_tag_t          dmat;
 122         struct memdesc         mem;
 123         bus_dmamap_callback_t *callback;
 124         void                  *callback_arg;
 125         STAILQ_ENTRY(bus_dmamap) links;
 126 };
 127
 128 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 129 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
 130 static struct bus_dmamap nobounce_dmamap;
 131
 132 static void init_bounce_pages(void *dummy);
 133 static int alloc_bounce_zone(bus_dma_tag_t dmat);
 134 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 135 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 136                                 int commit);
 137 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 138                                   vm_offset_t vaddr, bus_addr_t addr1,
 139                                   bus_addr_t addr2, bus_size_t size);
 140 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 141 int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 142 static void _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 143                                     pmap_t pmap, void *buf, bus_size_t buflen,
 144                                     int flags);
 145 static void _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 146                                    vm_paddr_t buf, bus_size_t buflen,
 147                                    int flags);
 148 static int _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 149                                      int flags);
 150
 151 /*
 152  * Allocate a device specific dma_tag.
 153  */
 154 static int
 155 bounce_bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 156     bus_addr_t boundary, bus_addr_t lowaddr, bus_addr_t highaddr,
 157     bus_dma_filter_t *filter, void *filterarg, bus_size_t maxsize,
 158     int nsegments, bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
 159     void *lockfuncarg, bus_dma_tag_t *dmat)
 160 {
 161         bus_dma_tag_t newtag;
 162         int error;
 163
 164         *dmat = NULL;
 165         error = common_bus_dma_tag_create(parent != NULL ? &parent->common :
 166             NULL, alignment, boundary, lowaddr, highaddr, filter, filterarg,
 167             maxsize, nsegments, maxsegsz, flags, lockfunc, lockfuncarg,
 168             sizeof (struct bus_dma_tag), (void **)&newtag);
 169         if (error != 0)
 170                 return (error);
 171
 172         newtag->common.impl = &bus_dma_bounce_impl;
 173         newtag->map_count = 0;
 174         newtag->segments = NULL;
 175
 176         if (parent != NULL && ((newtag->common.filter != NULL) ||
 177             ((parent->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0)))
 178                 newtag->bounce_flags |= BUS_DMA_COULD_BOUNCE;
 179
 180         if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem) ||
 181             newtag->common.alignment > 1)
 182                 newtag->bounce_flags |= BUS_DMA_COULD_BOUNCE;
 183
 184         if (((newtag->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 185             (flags & BUS_DMA_ALLOCNOW) != 0) {
 186                 struct bounce_zone *bz;
 187
 188                 /* Must bounce */
 189                 if ((error = alloc_bounce_zone(newtag)) != 0) {
 190                         free(newtag, M_DEVBUF);
 191                         return (error);
 192                 }
 193                 bz = newtag->bounce_zone;
 194
 195                 if (ptoa(bz->total_bpages) < maxsize) {
 196                         int pages;
 197
 198                         pages = atop(maxsize) - bz->total_bpages;
 199
 200                         /* Add pages to our bounce pool */
 201                         if (alloc_bounce_pages(newtag, pages) < pages)
 202                                 error = ENOMEM;
 203                 }
 204                 /* Performed initial allocation */
 205                 newtag->bounce_flags |= BUS_DMA_MIN_ALLOC_COMP;
 206         } else
 207                 error = 0;
 208
 209         if (error != 0)
 210                 free(newtag, M_DEVBUF);
 211         else
 212                 *dmat = newtag;
 213         CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
 214             __func__, newtag, (newtag != NULL ? newtag->common.flags : 0),
 215             error);
 216         return (error);
 217 }
 218
 219 static int
 220 bounce_bus_dma_tag_destroy(bus_dma_tag_t dmat)
 221 {
 222         bus_dma_tag_t dmat_copy, parent;
 223         int error;
 224
 225         error = 0;
 226         dmat_copy = dmat;
 227
 228         if (dmat != NULL) {
 229                 if (dmat->map_count != 0) {
 230                         error = EBUSY;
 231                         goto out;
 232                 }
 233                 while (dmat != NULL) {
 234                         parent = (bus_dma_tag_t)dmat->common.parent;
 235                         atomic_subtract_int(&dmat->common.ref_count, 1);
 236                         if (dmat->common.ref_count == 0) {
 237                                 if (dmat->segments != NULL)
 238                                         free(dmat->segments, M_DEVBUF);
 239                                 free(dmat, M_DEVBUF);
 240                                 /*
 241                                  * Last reference count, so
 242                                  * release our reference
 243                                  * count on our parent.
 244                                  */
 245                                 dmat = parent;
 246                         } else
 247                                 dmat = NULL;
 248                 }
 249         }
 250 out:
 251         CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
 252         return (error);
 253 }
 254
 255 /*
 256  * Allocate a handle for mapping from kva/uva/physical
 257  * address space into bus device space.
 258  */
 259 static int
 260 bounce_bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 261 {
 262         struct bounce_zone *bz;
 263         int error, maxpages, pages;
 264
 265         error = 0;
 266
 267         if (dmat->segments == NULL) {
 268                 dmat->segments = (bus_dma_segment_t *)malloc(
 269                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 270                     M_DEVBUF, M_NOWAIT);
 271                 if (dmat->segments == NULL) {
 272                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 273                             __func__, dmat, ENOMEM);
 274                         return (ENOMEM);
 275                 }
 276         }
 277
 278         /*
 279          * Bouncing might be required if the driver asks for an active
 280          * exclusion region, a data alignment that is stricter than 1, and/or
 281          * an active address boundary.
 282          */
 283         if (dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) {
 284                 /* Must bounce */
 285                 if (dmat->bounce_zone == NULL) {
 286                         if ((error = alloc_bounce_zone(dmat)) != 0)
 287                                 return (error);
 288                 }
 289                 bz = dmat->bounce_zone;
 290
 291                 *mapp = (bus_dmamap_t)malloc(sizeof(**mapp), M_DEVBUF,
 292                     M_NOWAIT | M_ZERO);
 293                 if (*mapp == NULL) {
 294                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 295                             __func__, dmat, ENOMEM);
 296                         return (ENOMEM);
 297                 }
 298
 299                 /* Initialize the new map */
 300                 STAILQ_INIT(&((*mapp)->bpages));
 301
 302                 /*
 303                  * Attempt to add pages to our pool on a per-instance
 304                  * basis up to a sane limit.
 305                  */
 306                 if (dmat->common.alignment > 1)
 307                         maxpages = MAX_BPAGES;
 308                 else
 309                         maxpages = MIN(MAX_BPAGES, Maxmem -
 310                             atop(dmat->common.lowaddr));
 311                 if ((dmat->bounce_flags & BUS_DMA_MIN_ALLOC_COMP) == 0 ||
 312                     (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 313                         pages = MAX(atop(dmat->common.maxsize), 1);
 314                         pages = MIN(maxpages - bz->total_bpages, pages);
 315                         pages = MAX(pages, 1);
 316                         if (alloc_bounce_pages(dmat, pages) < pages)
 317                                 error = ENOMEM;
 318                         if ((dmat->bounce_flags & BUS_DMA_MIN_ALLOC_COMP)
 319                             == 0) {
 320                                 if (error == 0) {
 321                                         dmat->bounce_flags |=
 322                                             BUS_DMA_MIN_ALLOC_COMP;
 323                                 }
 324                         } else
 325                                 error = 0;
 326                 }
 327                 bz->map_count++;
 328         } else {
 329                 *mapp = NULL;
 330         }
 331         if (error == 0)
 332                 dmat->map_count++;
 333         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 334             __func__, dmat, dmat->common.flags, error);
 335         return (error);
 336 }
 337
 338 /*
 339  * Destroy a handle for mapping from kva/uva/physical
 340  * address space into bus device space.
 341  */
 342 static int
 343 bounce_bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 344 {
 345
 346         if (map != NULL && map != &nobounce_dmamap) {
 347                 if (STAILQ_FIRST(&map->bpages) != NULL) {
 348                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 349                             __func__, dmat, EBUSY);
 350                         return (EBUSY);
 351                 }
 352                 if (dmat->bounce_zone)
 353                         dmat->bounce_zone->map_count--;
 354                 free(map, M_DEVBUF);
 355         }
 356         dmat->map_count--;
 357         CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
 358         return (0);
 359 }
 360
 361
 362 /*
 363  * Allocate a piece of memory that can be efficiently mapped into
 364  * bus device space based on the constraints lited in the dma tag.
 365  * A dmamap to for use with dmamap_load is also allocated.
 366  */
 367 static int
 368 bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 369     bus_dmamap_t *mapp)
 370 {
 371         vm_memattr_t attr;
 372         int mflags;
 373
 374         if (flags & BUS_DMA_NOWAIT)
 375                 mflags = M_NOWAIT;
 376         else
 377                 mflags = M_WAITOK;
 378
 379         /* If we succeed, no mapping/bouncing will be required */
 380         *mapp = NULL;
 381
 382         if (dmat->segments == NULL) {
 383                 dmat->segments = (bus_dma_segment_t *)malloc(
 384                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 385                     M_DEVBUF, mflags);
 386                 if (dmat->segments == NULL) {
 387                         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 388                             __func__, dmat, dmat->common.flags, ENOMEM);
 389                         return (ENOMEM);
 390                 }
 391         }
 392         if (flags & BUS_DMA_ZERO)
 393                 mflags |= M_ZERO;
 394         if (flags & BUS_DMA_NOCACHE)
 395                 attr = VM_MEMATTR_UNCACHEABLE;
 396         else
 397                 attr = VM_MEMATTR_DEFAULT;
 398
 399         /*
 400          * XXX:
 401          * (dmat->alignment <= dmat->maxsize) is just a quick hack; the exact
 402          * alignment guarantees of malloc need to be nailed down, and the
 403          * code below should be rewritten to take that into account.
 404          *
 405          * In the meantime, we'll warn the user if malloc gets it wrong.
 406          */
 407         if ((dmat->common.maxsize <= PAGE_SIZE) &&
 408            (dmat->common.alignment <= dmat->common.maxsize) &&
 409             dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 410             attr == VM_MEMATTR_DEFAULT) {
 411                 *vaddr = malloc(dmat->common.maxsize, M_DEVBUF, mflags);
 412         } else if (dmat->common.nsegments >= btoc(dmat->common.maxsize) &&
 413             dmat->common.alignment <= PAGE_SIZE &&
 414             (dmat->common.boundary == 0 ||
 415             dmat->common.boundary >= dmat->common.lowaddr)) {
 416                 /* Page-based multi-segment allocations allowed */
 417                 *vaddr = (void *)kmem_alloc_attr(kernel_arena,
 418                     dmat->common.maxsize, mflags, 0ul, dmat->common.lowaddr,
 419                     attr);
 420                 dmat->bounce_flags |= BUS_DMA_KMEM_ALLOC;
 421         } else {
 422                 *vaddr = (void *)kmem_alloc_contig(kernel_arena,
 423                     dmat->common.maxsize, mflags, 0ul, dmat->common.lowaddr,
 424                     dmat->common.alignment != 0 ? dmat->common.alignment : 1ul,
 425                     dmat->common.boundary, attr);
 426                 dmat->bounce_flags |= BUS_DMA_KMEM_ALLOC;
 427         }
 428         if (*vaddr == NULL) {
 429                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 430                     __func__, dmat, dmat->common.flags, ENOMEM);
 431                 return (ENOMEM);
 432         } else if (vtophys(*vaddr) & (dmat->common.alignment - 1)) {
 433                 printf("bus_dmamem_alloc failed to align memory properly.\n");
 434         }
 435         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 436             __func__, dmat, dmat->common.flags, 0);
 437         return (0);
 438 }
 439
 440 /*
 441  * Free a piece of memory and it's allociated dmamap, that was allocated
 442  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 443  */
 444 static void
 445 bounce_bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 446 {
 447         /*
 448          * dmamem does not need to be bounced, so the map should be
 449          * NULL and the BUS_DMA_KMEM_ALLOC flag cleared if malloc()
 450          * was used and set if kmem_alloc_contig() was used.
 451          */
 452         if (map != NULL)
 453                 panic("bus_dmamem_free: Invalid map freed\n");
 454         if ((dmat->bounce_flags & BUS_DMA_KMEM_ALLOC) == 0)
 455                 free(vaddr, M_DEVBUF);
 456         else
 457                 kmem_free(kernel_arena, (vm_offset_t)vaddr,
 458                     dmat->common.maxsize);
 459         CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat,
 460             dmat->bounce_flags);
 461 }
 462
 463 static void
 464 _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
 465     bus_size_t buflen, int flags)
 466 {
 467         bus_addr_t curaddr;
 468         bus_size_t sgsize;
 469
 470         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 471                 /*
 472                  * Count the number of bounce pages
 473                  * needed in order to complete this transfer
 474                  */
 475                 curaddr = buf;
 476                 while (buflen != 0) {
 477                         sgsize = MIN(buflen, dmat->common.maxsegsz);
 478                         if (bus_dma_run_filter(&dmat->common, curaddr)) {
 479                                 sgsize = MIN(sgsize,
 480                                     PAGE_SIZE - (curaddr & PAGE_MASK));
 481                                 map->pagesneeded++;
 482                         }
 483                         curaddr += sgsize;
 484                         buflen -= sgsize;
 485                 }
 486                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 487         }
 488 }
 489
 490 static void
 491 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
 492     void *buf, bus_size_t buflen, int flags)
 493 {
 494         vm_offset_t vaddr;
 495         vm_offset_t vendaddr;
 496         bus_addr_t paddr;
 497         bus_size_t sg_len;
 498
 499         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 500                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 501                     "alignment= %d", dmat->common.lowaddr,
 502                     ptoa((vm_paddr_t)Maxmem),
 503                     dmat->common.boundary, dmat->common.alignment);
 504                 CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
 505                     map, &nobounce_dmamap, map->pagesneeded);
 506                 /*
 507                  * Count the number of bounce pages
 508                  * needed in order to complete this transfer
 509                  */
 510                 vaddr = (vm_offset_t)buf;
 511                 vendaddr = (vm_offset_t)buf + buflen;
 512
 513                 while (vaddr < vendaddr) {
 514                         sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
 515                         if (pmap == kernel_pmap)
 516                                 paddr = pmap_kextract(vaddr);
 517                         else
 518                                 paddr = pmap_extract(pmap, vaddr);
 519                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 520                                 sg_len = roundup2(sg_len,
 521                                     dmat->common.alignment);
 522                                 map->pagesneeded++;
 523                         }
 524                         vaddr += sg_len;
 525                 }
 526                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 527         }
 528 }
 529
 530 static void
 531 _bus_dmamap_count_ma(bus_dma_tag_t dmat, bus_dmamap_t map, struct vm_page **ma,
 532     int ma_offs, bus_size_t buflen, int flags)
 533 {
 534         bus_size_t sg_len, max_sgsize;
 535         int page_index;
 536         vm_paddr_t paddr;
 537
 538         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 539                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 540                     "alignment= %d", dmat->common.lowaddr,
 541                     ptoa((vm_paddr_t)Maxmem),
 542                     dmat->common.boundary, dmat->common.alignment);
 543                 CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
 544                     map, &nobounce_dmamap, map->pagesneeded);
 545
 546                 /*
 547                  * Count the number of bounce pages
 548                  * needed in order to complete this transfer
 549                  */
 550                 page_index = 0;
 551                 while (buflen > 0) {
 552                         paddr = VM_PAGE_TO_PHYS(ma[page_index]) + ma_offs;
 553                         sg_len = PAGE_SIZE - ma_offs;
 554                         max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 555                         sg_len = MIN(sg_len, max_sgsize);
 556                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 557                                 sg_len = roundup2(sg_len,
 558                                     dmat->common.alignment);
 559                                 sg_len = MIN(sg_len, max_sgsize);
 560                                 KASSERT((sg_len & (dmat->common.alignment - 1))
 561                                     == 0, ("Segment size is not aligned"));
 562                                 map->pagesneeded++;
 563                         }
 564                         if (((ma_offs + sg_len) & ~PAGE_MASK) != 0)
 565                                 page_index++;
 566                         ma_offs = (ma_offs + sg_len) & PAGE_MASK;
 567                         KASSERT(buflen >= sg_len,
 568                             ("Segment length overruns original buffer"));
 569                         buflen -= sg_len;
 570                 }
 571                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 572         }
 573 }
 574
 575 static int
 576 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
 577 {
 578
 579         /* Reserve Necessary Bounce Pages */
 580         mtx_lock(&bounce_lock);
 581         if (flags & BUS_DMA_NOWAIT) {
 582                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
 583                         mtx_unlock(&bounce_lock);
 584                         return (ENOMEM);
 585                 }
 586         } else {
 587                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
 588                         /* Queue us for resources */
 589                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 590                         mtx_unlock(&bounce_lock);
 591                         return (EINPROGRESS);
 592                 }
 593         }
 594         mtx_unlock(&bounce_lock);
 595
 596         return (0);
 597 }
 598
 599 /*
 600  * Add a single contiguous physical range to the segment list.
 601  */
 602 static int
 603 _bus_dmamap_addseg(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t curaddr,
 604     bus_size_t sgsize, bus_dma_segment_t *segs, int *segp)
 605 {
 606         bus_addr_t baddr, bmask;
 607         int seg;
 608
 609         /*
 610          * Make sure we don't cross any boundaries.
 611          */
 612         bmask = ~(dmat->common.boundary - 1);
 613         if (dmat->common.boundary > 0) {
 614                 baddr = (curaddr + dmat->common.boundary) & bmask;
 615                 if (sgsize > (baddr - curaddr))
 616                         sgsize = (baddr - curaddr);
 617         }
 618
 619         /*
 620          * Insert chunk into a segment, coalescing with
 621          * previous segment if possible.
 622          */
 623         seg = *segp;
 624         if (seg == -1) {
 625                 seg = 0;
 626                 segs[seg].ds_addr = curaddr;
 627                 segs[seg].ds_len = sgsize;
 628         } else {
 629                 if (curaddr == segs[seg].ds_addr + segs[seg].ds_len &&
 630                     (segs[seg].ds_len + sgsize) <= dmat->common.maxsegsz &&
 631                     (dmat->common.boundary == 0 ||
 632                      (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 633                         segs[seg].ds_len += sgsize;
 634                 else {
 635                         if (++seg >= dmat->common.nsegments)
 636                                 return (0);
 637                         segs[seg].ds_addr = curaddr;
 638                         segs[seg].ds_len = sgsize;
 639                 }
 640         }
 641         *segp = seg;
 642         return (sgsize);
 643 }
 644
 645 /*
 646  * Utility function to load a physical buffer.  segp contains
 647  * the starting segment on entrace, and the ending segment on exit.
 648  */
 649 static int
 650 bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 651     vm_paddr_t buf, bus_size_t buflen, int flags, bus_dma_segment_t *segs,
 652     int *segp)
 653 {
 654         bus_size_t sgsize;
 655         bus_addr_t curaddr;
 656         int error;
 657
 658         if (map == NULL)
 659                 map = &nobounce_dmamap;
 660
 661         if (segs == NULL)
 662                 segs = dmat->segments;
 663
 664         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 665                 _bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
 666                 if (map->pagesneeded != 0) {
 667                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 668                         if (error)
 669                                 return (error);
 670                 }
 671         }
 672
 673         while (buflen > 0) {
 674                 curaddr = buf;
 675                 sgsize = MIN(buflen, dmat->common.maxsegsz);
 676                 if (((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 677                     map->pagesneeded != 0 &&
 678                     bus_dma_run_filter(&dmat->common, curaddr)) {
 679                         sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
 680                         curaddr = add_bounce_page(dmat, map, 0, curaddr, 0,
 681                             sgsize);
 682                 }
 683                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 684                     segp);
 685                 if (sgsize == 0)
 686                         break;
 687                 buf += sgsize;
 688                 buflen -= sgsize;
 689         }
 690
 691         /*
 692          * Did we fit?
 693          */
 694         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 695 }
 696
 697 /*
 698  * Utility function to load a linear buffer.  segp contains
 699  * the starting segment on entrace, and the ending segment on exit.
 700  */
 701 static int
 702 bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 703     bus_size_t buflen, pmap_t pmap, int flags, bus_dma_segment_t *segs,
 704     int *segp)
 705 {
 706         bus_size_t sgsize, max_sgsize;
 707         bus_addr_t curaddr;
 708         vm_offset_t kvaddr, vaddr;
 709         int error;
 710
 711         if (map == NULL)
 712                 map = &nobounce_dmamap;
 713
 714         if (segs == NULL)
 715                 segs = dmat->segments;
 716
 717         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 718                 _bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
 719                 if (map->pagesneeded != 0) {
 720                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 721                         if (error)
 722                                 return (error);
 723                 }
 724         }
 725
 726         vaddr = (vm_offset_t)buf;
 727         while (buflen > 0) {
 728                 /*
 729                  * Get the physical address for this segment.
 730                  */
 731                 if (pmap == kernel_pmap) {
 732                         curaddr = pmap_kextract(vaddr);
 733                         kvaddr = vaddr;
 734                 } else {
 735                         curaddr = pmap_extract(pmap, vaddr);
 736                         kvaddr = 0;
 737                 }
 738
 739                 /*
 740                  * Compute the segment size, and adjust counts.
 741                  */
 742                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 743                 sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
 744                 if (((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 745                     map->pagesneeded != 0 &&
 746                     bus_dma_run_filter(&dmat->common, curaddr)) {
 747                         sgsize = roundup2(sgsize, dmat->common.alignment);
 748                         sgsize = MIN(sgsize, max_sgsize);
 749                         curaddr = add_bounce_page(dmat, map, kvaddr, curaddr, 0,
 750                             sgsize);
 751                 } else {
 752                         sgsize = MIN(sgsize, max_sgsize);
 753                 }
 754                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 755                     segp);
 756                 if (sgsize == 0)
 757                         break;
 758                 vaddr += sgsize;
 759                 buflen -= sgsize;
 760         }
 761
 762         /*
 763          * Did we fit?
 764          */
 765         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 766 }
 767
 768 static int
 769 bounce_bus_dmamap_load_ma(bus_dma_tag_t dmat, bus_dmamap_t map,
 770     struct vm_page **ma, bus_size_t buflen, int ma_offs, int flags,
 771     bus_dma_segment_t *segs, int *segp)
 772 {
 773         vm_paddr_t paddr, next_paddr;
 774         int error, page_index;
 775         bus_size_t sgsize, max_sgsize;
 776
 777         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
 778                 /*
 779                  * If we have to keep the offset of each page this function
 780                  * is not suitable, switch back to bus_dmamap_load_ma_triv
 781                  * which is going to do the right thing in this case.
 782                  */
 783                 error = bus_dmamap_load_ma_triv(dmat, map, ma, buflen, ma_offs,
 784                     flags, segs, segp);
 785                 return (error);
 786         }
 787
 788         if (map == NULL)
 789                 map = &nobounce_dmamap;
 790
 791         if (segs == NULL)
 792                 segs = dmat->segments;
 793
 794         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 795                 _bus_dmamap_count_ma(dmat, map, ma, ma_offs, buflen, flags);
 796                 if (map->pagesneeded != 0) {
 797                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 798                         if (error)
 799                                 return (error);
 800                 }
 801         }
 802
 803         page_index = 0;
 804         while (buflen > 0) {
 805                 /*
 806                  * Compute the segment size, and adjust counts.
 807                  */
 808                 paddr = VM_PAGE_TO_PHYS(ma[page_index]) + ma_offs;
 809                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 810                 sgsize = PAGE_SIZE - ma_offs;
 811                 if (((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 812                     map->pagesneeded != 0 &&
 813                     bus_dma_run_filter(&dmat->common, paddr)) {
 814                         sgsize = roundup2(sgsize, dmat->common.alignment);
 815                         sgsize = MIN(sgsize, max_sgsize);
 816                         KASSERT((sgsize & (dmat->common.alignment - 1)) == 0,
 817                             ("Segment size is not aligned"));
 818                         /*
 819                          * Check if two pages of the user provided buffer
 820                          * are used.
 821                          */
 822                         if ((ma_offs + sgsize) > PAGE_SIZE)
 823                                 next_paddr =
 824                                     VM_PAGE_TO_PHYS(ma[page_index + 1]);
 825                         else
 826                                 next_paddr = 0;
 827                         paddr = add_bounce_page(dmat, map, 0, paddr,
 828                             next_paddr, sgsize);
 829                 } else {
 830                         sgsize = MIN(sgsize, max_sgsize);
 831                 }
 832                 sgsize = _bus_dmamap_addseg(dmat, map, paddr, sgsize, segs,
 833                     segp);
 834                 if (sgsize == 0)
 835                         break;
 836                 KASSERT(buflen >= sgsize,
 837                     ("Segment length overruns original buffer"));
 838                 buflen -= sgsize;
 839                 if (((ma_offs + sgsize) & ~PAGE_MASK) != 0)
 840                         page_index++;
 841                 ma_offs = (ma_offs + sgsize) & PAGE_MASK;
 842         }
 843
 844         /*
 845          * Did we fit?
 846          */
 847         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 848 }
 849
 850 static void
 851 bounce_bus_dmamap_waitok(bus_dma_tag_t dmat, bus_dmamap_t map,
 852     struct memdesc *mem, bus_dmamap_callback_t *callback, void *callback_arg)
 853 {
 854
 855         if (map == NULL)
 856                 return;
 857         map->mem = *mem;
 858         map->dmat = dmat;
 859         map->callback = callback;
 860         map->callback_arg = callback_arg;
 861 }
 862
 863 static bus_dma_segment_t *
 864 bounce_bus_dmamap_complete(bus_dma_tag_t dmat, bus_dmamap_t map,
 865     bus_dma_segment_t *segs, int nsegs, int error)
 866 {
 867
 868         if (segs == NULL)
 869                 segs = dmat->segments;
 870         return (segs);
 871 }
 872
 873 /*
 874  * Release the mapping held by map.
 875  */
 876 static void
 877 bounce_bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 878 {
 879         struct bounce_page *bpage;
 880
 881         if (map == NULL)
 882                 return;
 883
 884         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 885                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 886                 free_bounce_page(dmat, bpage);
 887         }
 888 }
 889
 890 static void
 891 bounce_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map,
 892     bus_dmasync_op_t op)
 893 {
 894         struct bounce_page *bpage;
 895         vm_offset_t datavaddr, tempvaddr;
 896         bus_size_t datacount1, datacount2;
 897
 898         if (map == NULL || (bpage = STAILQ_FIRST(&map->bpages)) == NULL)
 899                 return;
 900
 901         /*
 902          * Handle data bouncing.  We might also want to add support for
 903          * invalidating the caches on broken hardware.
 904          */
 905         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
 906             "performing bounce", __func__, dmat, dmat->common.flags, op);
 907
 908         if ((op & BUS_DMASYNC_PREWRITE) != 0) {
 909                 while (bpage != NULL) {
 910                         tempvaddr = 0;
 911                         datavaddr = bpage->datavaddr;
 912                         datacount1 = bpage->datacount;
 913                         if (datavaddr == 0) {
 914                                 tempvaddr =
 915                                     pmap_quick_enter_page(bpage->datapage[0]);
 916                                 datavaddr = tempvaddr | bpage->dataoffs;
 917                                 datacount1 = min(PAGE_SIZE - bpage->dataoffs,
 918                                     datacount1);
 919                         }
 920
 921                         bcopy((void *)datavaddr,
 922                             (void *)bpage->vaddr, datacount1);
 923
 924                         if (tempvaddr != 0)
 925                                 pmap_quick_remove_page(tempvaddr);
 926
 927                         if (bpage->datapage[1] == 0) {
 928                                 KASSERT(datacount1 == bpage->datacount,
 929                 ("Mismatch between data size and provided memory space"));
 930                                 goto next_w;
 931                         }
 932
 933                         /*
 934                          * We are dealing with an unmapped buffer that expands
 935                          * over two pages.
 936                          */
 937                         datavaddr = pmap_quick_enter_page(bpage->datapage[1]);
 938                         datacount2 = bpage->datacount - datacount1;
 939                         bcopy((void *)datavaddr,
 940                             (void *)(bpage->vaddr + datacount1), datacount2);
 941                         pmap_quick_remove_page(datavaddr);
 942
 943 next_w:
 944                         bpage = STAILQ_NEXT(bpage, links);
 945                 }
 946                 dmat->bounce_zone->total_bounced++;
 947         }
 948
 949         if ((op & BUS_DMASYNC_POSTREAD) != 0) {
 950                 while (bpage != NULL) {
 951                         tempvaddr = 0;
 952                         datavaddr = bpage->datavaddr;
 953                         datacount1 = bpage->datacount;
 954                         if (datavaddr == 0) {
 955                                 tempvaddr =
 956                                     pmap_quick_enter_page(bpage->datapage[0]);
 957                                 datavaddr = tempvaddr | bpage->dataoffs;
 958                                 datacount1 = min(PAGE_SIZE - bpage->dataoffs,
 959                                     datacount1);
 960                         }
 961
 962                         bcopy((void *)bpage->vaddr, (void *)datavaddr,
 963                             datacount1);
 964
 965                         if (tempvaddr != 0)
 966                                 pmap_quick_remove_page(tempvaddr);
 967
 968                         if (bpage->datapage[1] == 0) {
 969                                 KASSERT(datacount1 == bpage->datacount,
 970                 ("Mismatch between data size and provided memory space"));
 971                                 goto next_r;
 972                         }
 973
 974                         /*
 975                          * We are dealing with an unmapped buffer that expands
 976                          * over two pages.
 977                          */
 978                         datavaddr = pmap_quick_enter_page(bpage->datapage[1]);
 979                         datacount2 = bpage->datacount - datacount1;
 980                         bcopy((void *)(bpage->vaddr + datacount1),
 981                             (void *)datavaddr, datacount2);
 982                         pmap_quick_remove_page(datavaddr);
 983
 984 next_r:
 985                         bpage = STAILQ_NEXT(bpage, links);
 986                 }
 987                 dmat->bounce_zone->total_bounced++;
 988         }
 989 }
 990
 991 static void
 992 init_bounce_pages(void *dummy __unused)
 993 {
 994
 995         total_bpages = 0;
 996         STAILQ_INIT(&bounce_zone_list);
 997         STAILQ_INIT(&bounce_map_waitinglist);
 998         STAILQ_INIT(&bounce_map_callbacklist);
 999         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
1000 }
1001 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
1002
1003 static struct sysctl_ctx_list *
1004 busdma_sysctl_tree(struct bounce_zone *bz)
1005 {
1006
1007         return (&bz->sysctl_tree);
1008 }
1009
1010 static struct sysctl_oid *
1011 busdma_sysctl_tree_top(struct bounce_zone *bz)
1012 {
1013
1014         return (bz->sysctl_tree_top);
1015 }
1016
1017 static int
1018 alloc_bounce_zone(bus_dma_tag_t dmat)
1019 {
1020         struct bounce_zone *bz;
1021
1022         /* Check to see if we already have a suitable zone */
1023         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1024                 if ((dmat->common.alignment <= bz->alignment) &&
1025                     (dmat->common.lowaddr >= bz->lowaddr)) {
1026                         dmat->bounce_zone = bz;
1027                         return (0);
1028                 }
1029         }
1030
1031         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
1032             M_NOWAIT | M_ZERO)) == NULL)
1033                 return (ENOMEM);
1034
1035         STAILQ_INIT(&bz->bounce_page_list);
1036         bz->free_bpages = 0;
1037         bz->reserved_bpages = 0;
1038         bz->active_bpages = 0;
1039         bz->lowaddr = dmat->common.lowaddr;
1040         bz->alignment = MAX(dmat->common.alignment, PAGE_SIZE);
1041         bz->map_count = 0;
1042         snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1043         busdma_zonecount++;
1044         snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1045         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1046         dmat->bounce_zone = bz;
1047
1048         sysctl_ctx_init(&bz->sysctl_tree);
1049         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
1050             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1051             CTLFLAG_RD, 0, "");
1052         if (bz->sysctl_tree_top == NULL) {
1053                 sysctl_ctx_free(&bz->sysctl_tree);
1054                 return (0);     /* XXX error code? */
1055         }
1056
1057         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1058             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1059             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1060             "Total bounce pages");
1061         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1062             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1063             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1064             "Free bounce pages");
1065         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1066             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1067             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1068             "Reserved bounce pages");
1069         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1070             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1071             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1072             "Active bounce pages");
1073         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1074             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1075             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1076             "Total bounce requests");
1077         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1078             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1079             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1080             "Total bounce requests that were deferred");
1081         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
1082             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1083             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1084         SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
1085             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1086             "alignment", CTLFLAG_RD, &bz->alignment, "");
1087
1088         return (0);
1089 }
1090
1091 static int
1092 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
1093 {
1094         struct bounce_zone *bz;
1095         int count;
1096
1097         bz = dmat->bounce_zone;
1098         count = 0;
1099         while (numpages > 0) {
1100                 struct bounce_page *bpage;
1101
1102                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
1103                                                      M_NOWAIT | M_ZERO);
1104
1105                 if (bpage == NULL)
1106                         break;
1107                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1108                                                          M_NOWAIT, 0ul,
1109                                                          bz->lowaddr,
1110                                                          PAGE_SIZE,
1111                                                          0);
1112                 if (bpage->vaddr == 0) {
1113                         free(bpage, M_DEVBUF);
1114                         break;
1115                 }
1116                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1117                 mtx_lock(&bounce_lock);
1118                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1119                 total_bpages++;
1120                 bz->total_bpages++;
1121                 bz->free_bpages++;
1122                 mtx_unlock(&bounce_lock);
1123                 count++;
1124                 numpages--;
1125         }
1126         return (count);
1127 }
1128
1129 static int
1130 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1131 {
1132         struct bounce_zone *bz;
1133         int pages;
1134
1135         mtx_assert(&bounce_lock, MA_OWNED);
1136         bz = dmat->bounce_zone;
1137         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1138         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
1139                 return (map->pagesneeded - (map->pagesreserved + pages));
1140         bz->free_bpages -= pages;
1141         bz->reserved_bpages += pages;
1142         map->pagesreserved += pages;
1143         pages = map->pagesneeded - map->pagesreserved;
1144
1145         return (pages);
1146 }
1147
1148 static bus_addr_t
1149 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1150                 bus_addr_t addr1, bus_addr_t addr2, bus_size_t size)
1151 {
1152         struct bounce_zone *bz;
1153         struct bounce_page *bpage;
1154
1155         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
1156         KASSERT(map != NULL && map != &nobounce_dmamap,
1157             ("add_bounce_page: bad map %p", map));
1158
1159         bz = dmat->bounce_zone;
1160         if (map->pagesneeded == 0)
1161                 panic("add_bounce_page: map doesn't need any pages");
1162         map->pagesneeded--;
1163
1164         if (map->pagesreserved == 0)
1165                 panic("add_bounce_page: map doesn't need any pages");
1166         map->pagesreserved--;
1167
1168         mtx_lock(&bounce_lock);
1169         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1170         if (bpage == NULL)
1171                 panic("add_bounce_page: free page list is empty");
1172
1173         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1174         bz->reserved_bpages--;
1175         bz->active_bpages++;
1176         mtx_unlock(&bounce_lock);
1177
1178         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1179                 /* Page offset needs to be preserved. */
1180                 bpage->vaddr |= addr1 & PAGE_MASK;
1181                 bpage->busaddr |= addr1 & PAGE_MASK;
1182                 KASSERT(addr2 == 0,
1183         ("Trying to bounce multiple pages with BUS_DMA_KEEP_PG_OFFSET"));
1184         }
1185         bpage->datavaddr = vaddr;
1186         bpage->datapage[0] = PHYS_TO_VM_PAGE(addr1);
1187         KASSERT((addr2 & PAGE_MASK) == 0, ("Second page is not aligned"));
1188         bpage->datapage[1] = PHYS_TO_VM_PAGE(addr2);
1189         bpage->dataoffs = addr1 & PAGE_MASK;
1190         bpage->datacount = size;
1191         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
1192         return (bpage->busaddr);
1193 }
1194
1195 static void
1196 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1197 {
1198         struct bus_dmamap *map;
1199         struct bounce_zone *bz;
1200
1201         bz = dmat->bounce_zone;
1202         bpage->datavaddr = 0;
1203         bpage->datacount = 0;
1204         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1205                 /*
1206                  * Reset the bounce page to start at offset 0.  Other uses
1207                  * of this bounce page may need to store a full page of
1208                  * data and/or assume it starts on a page boundary.
1209                  */
1210                 bpage->vaddr &= ~PAGE_MASK;
1211                 bpage->busaddr &= ~PAGE_MASK;
1212         }
1213
1214         mtx_lock(&bounce_lock);
1215         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1216         bz->free_bpages++;
1217         bz->active_bpages--;
1218         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
1219                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1220                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
1221                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
1222                             map, links);
1223                         busdma_swi_pending = 1;
1224                         bz->total_deferred++;
1225                         swi_sched(vm_ih, 0);
1226                 }
1227         }
1228         mtx_unlock(&bounce_lock);
1229 }
1230
1231 void
1232 busdma_swi(void)
1233 {
1234         bus_dma_tag_t dmat;
1235         struct bus_dmamap *map;
1236
1237         mtx_lock(&bounce_lock);
1238         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1239                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1240                 mtx_unlock(&bounce_lock);
1241                 dmat = map->dmat;
1242                 (dmat->common.lockfunc)(dmat->common.lockfuncarg, BUS_DMA_LOCK);
1243                 bus_dmamap_load_mem(map->dmat, map, &map->mem,
1244                     map->callback, map->callback_arg, BUS_DMA_WAITOK);
1245                 (dmat->common.lockfunc)(dmat->common.lockfuncarg,
1246                     BUS_DMA_UNLOCK);
1247                 mtx_lock(&bounce_lock);
1248         }
1249         mtx_unlock(&bounce_lock);
1250 }
1251
1252 struct bus_dma_impl bus_dma_bounce_impl = {
1253         .tag_create = bounce_bus_dma_tag_create,
1254         .tag_destroy = bounce_bus_dma_tag_destroy,
1255         .map_create = bounce_bus_dmamap_create,
1256         .map_destroy = bounce_bus_dmamap_destroy,
1257         .mem_alloc = bounce_bus_dmamem_alloc,
1258         .mem_free = bounce_bus_dmamem_free,
1259         .load_phys = bounce_bus_dmamap_load_phys,
1260         .load_buffer = bounce_bus_dmamap_load_buffer,
1261         .load_ma = bounce_bus_dmamap_load_ma,
1262         .map_waitok = bounce_bus_dmamap_waitok,
1263         .map_complete = bounce_bus_dmamap_complete,
1264         .map_unload = bounce_bus_dmamap_unload,
1265         .map_sync = bounce_bus_dmamap_sync
1266 };