sys/riscv/riscv/busdma_bounce.c

   1 /*-
   2  * Copyright (c) 1997, 1998 Justin T. Gibbs.
   3  * Copyright (c) 2015-2016 The FreeBSD Foundation
   4  * All rights reserved.
   5  *
   6  * Portions of this software were developed by Andrew Turner
   7  * under sponsorship of the FreeBSD Foundation.
   8  *
   9  * Portions of this software were developed by Semihalf
  10  * under sponsorship of the FreeBSD Foundation.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions, and the following disclaimer,
  17  *    without modification, immediately at the beginning of the file.
  18  * 2. The name of the author may not be used to endorse or promote products
  19  *    derived from this software without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  25  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36
  37 #include <sys/param.h>
  38 #include <sys/systm.h>
  39 #include <sys/malloc.h>
  40 #include <sys/bus.h>
  41 #include <sys/interrupt.h>
  42 #include <sys/kernel.h>
  43 #include <sys/ktr.h>
  44 #include <sys/lock.h>
  45 #include <sys/proc.h>
  46 #include <sys/memdesc.h>
  47 #include <sys/mutex.h>
  48 #include <sys/sysctl.h>
  49 #include <sys/uio.h>
  50
  51 #include <vm/vm.h>
  52 #include <vm/vm_extern.h>
  53 #include <vm/vm_kern.h>
  54 #include <vm/vm_page.h>
  55 #include <vm/vm_map.h>
  56
  57 #include <machine/atomic.h>
  58 #include <machine/bus.h>
  59 #include <machine/md_var.h>
  60 #include <machine/bus_dma_impl.h>
  61
  62 #define MAX_BPAGES 4096
  63
  64 enum {
  65         BF_COULD_BOUNCE         = 0x01,
  66         BF_MIN_ALLOC_COMP       = 0x02,
  67         BF_KMEM_ALLOC           = 0x04,
  68         BF_COHERENT             = 0x10,
  69 };
  70
  71 struct bounce_zone;
  72
  73 struct bus_dma_tag {
  74         struct bus_dma_tag_common common;
  75         int                     map_count;
  76         int                     bounce_flags;
  77         bus_dma_segment_t       *segments;
  78         struct bounce_zone      *bounce_zone;
  79 };
  80
  81 struct bounce_page {
  82         vm_offset_t     vaddr;          /* kva of bounce buffer */
  83         bus_addr_t      busaddr;        /* Physical address */
  84         vm_offset_t     datavaddr;      /* kva of client data */
  85         vm_page_t       datapage;       /* physical page of client data */
  86         vm_offset_t     dataoffs;       /* page offset of client data */
  87         bus_size_t      datacount;      /* client data count */
  88         STAILQ_ENTRY(bounce_page) links;
  89 };
  90
  91 int busdma_swi_pending;
  92
  93 struct bounce_zone {
  94         STAILQ_ENTRY(bounce_zone) links;
  95         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  96         int             total_bpages;
  97         int             free_bpages;
  98         int             reserved_bpages;
  99         int             active_bpages;
 100         int             total_bounced;
 101         int             total_deferred;
 102         int             map_count;
 103         bus_size_t      alignment;
 104         bus_addr_t      lowaddr;
 105         char            zoneid[8];
 106         char            lowaddrid[20];
 107         struct sysctl_ctx_list sysctl_tree;
 108         struct sysctl_oid *sysctl_tree_top;
 109 };
 110
 111 static struct mtx bounce_lock;
 112 static int total_bpages;
 113 static int busdma_zonecount;
 114 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
 115
 116 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
 117     "Busdma parameters");
 118 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
 119            "Total bounce pages");
 120
 121 struct sync_list {
 122         vm_offset_t     vaddr;          /* kva of client data */
 123         bus_addr_t      paddr;          /* physical address */
 124         vm_page_t       pages;          /* starting page of client data */
 125         bus_size_t      datacount;      /* client data count */
 126 };
 127
 128 struct bus_dmamap {
 129         struct bp_list         bpages;
 130         int                    pagesneeded;
 131         int                    pagesreserved;
 132         bus_dma_tag_t          dmat;
 133         struct memdesc         mem;
 134         bus_dmamap_callback_t *callback;
 135         void                  *callback_arg;
 136         STAILQ_ENTRY(bus_dmamap) links;
 137         u_int                   flags;
 138 #define DMAMAP_COULD_BOUNCE     (1 << 0)
 139 #define DMAMAP_FROM_DMAMEM      (1 << 1)
 140         int                     sync_count;
 141         struct sync_list        slist[];
 142 };
 143
 144 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 145 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
 146
 147 static void init_bounce_pages(void *dummy);
 148 static int alloc_bounce_zone(bus_dma_tag_t dmat);
 149 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 150 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 151     int commit);
 152 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 153     vm_offset_t vaddr, bus_addr_t addr, bus_size_t size);
 154 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 155 int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 156 static void _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 157     pmap_t pmap, void *buf, bus_size_t buflen, int flags);
 158 static void _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 159     vm_paddr_t buf, bus_size_t buflen, int flags);
 160 static int _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 161     int flags);
 162
 163 /*
 164  * Allocate a device specific dma_tag.
 165  */
 166 static int
 167 bounce_bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 168     bus_addr_t boundary, bus_addr_t lowaddr, bus_addr_t highaddr,
 169     bus_dma_filter_t *filter, void *filterarg, bus_size_t maxsize,
 170     int nsegments, bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
 171     void *lockfuncarg, bus_dma_tag_t *dmat)
 172 {
 173         bus_dma_tag_t newtag;
 174         int error;
 175
 176         *dmat = NULL;
 177         error = common_bus_dma_tag_create(parent != NULL ? &parent->common :
 178             NULL, alignment, boundary, lowaddr, highaddr, filter, filterarg,
 179             maxsize, nsegments, maxsegsz, flags, lockfunc, lockfuncarg,
 180             sizeof (struct bus_dma_tag), (void **)&newtag);
 181         if (error != 0)
 182                 return (error);
 183
 184         newtag->common.impl = &bus_dma_bounce_impl;
 185         newtag->map_count = 0;
 186         newtag->segments = NULL;
 187
 188         if ((flags & BUS_DMA_COHERENT) != 0)
 189                 newtag->bounce_flags |= BF_COHERENT;
 190
 191         if (parent != NULL) {
 192                 if ((newtag->common.filter != NULL ||
 193                     (parent->bounce_flags & BF_COULD_BOUNCE) != 0))
 194                         newtag->bounce_flags |= BF_COULD_BOUNCE;
 195
 196                 /* Copy some flags from the parent */
 197                 newtag->bounce_flags |= parent->bounce_flags & BF_COHERENT;
 198         }
 199
 200         if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem) ||
 201             newtag->common.alignment > 1)
 202                 newtag->bounce_flags |= BF_COULD_BOUNCE;
 203
 204         if (((newtag->bounce_flags & BF_COULD_BOUNCE) != 0) &&
 205             (flags & BUS_DMA_ALLOCNOW) != 0) {
 206                 struct bounce_zone *bz;
 207
 208                 /* Must bounce */
 209                 if ((error = alloc_bounce_zone(newtag)) != 0) {
 210                         free(newtag, M_DEVBUF);
 211                         return (error);
 212                 }
 213                 bz = newtag->bounce_zone;
 214
 215                 if (ptoa(bz->total_bpages) < maxsize) {
 216                         int pages;
 217
 218                         pages = atop(round_page(maxsize)) - bz->total_bpages;
 219
 220                         /* Add pages to our bounce pool */
 221                         if (alloc_bounce_pages(newtag, pages) < pages)
 222                                 error = ENOMEM;
 223                 }
 224                 /* Performed initial allocation */
 225                 newtag->bounce_flags |= BF_MIN_ALLOC_COMP;
 226         } else
 227                 error = 0;
 228
 229         if (error != 0)
 230                 free(newtag, M_DEVBUF);
 231         else
 232                 *dmat = newtag;
 233         CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
 234             __func__, newtag, (newtag != NULL ? newtag->common.flags : 0),
 235             error);
 236         return (error);
 237 }
 238
 239 static int
 240 bounce_bus_dma_tag_destroy(bus_dma_tag_t dmat)
 241 {
 242         bus_dma_tag_t dmat_copy, parent;
 243         int error;
 244
 245         error = 0;
 246         dmat_copy = dmat;
 247
 248         if (dmat != NULL) {
 249                 if (dmat->map_count != 0) {
 250                         error = EBUSY;
 251                         goto out;
 252                 }
 253                 while (dmat != NULL) {
 254                         parent = (bus_dma_tag_t)dmat->common.parent;
 255                         atomic_subtract_int(&dmat->common.ref_count, 1);
 256                         if (dmat->common.ref_count == 0) {
 257                                 if (dmat->segments != NULL)
 258                                         free(dmat->segments, M_DEVBUF);
 259                                 free(dmat, M_DEVBUF);
 260                                 /*
 261                                  * Last reference count, so
 262                                  * release our reference
 263                                  * count on our parent.
 264                                  */
 265                                 dmat = parent;
 266                         } else
 267                                 dmat = NULL;
 268                 }
 269         }
 270 out:
 271         CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
 272         return (error);
 273 }
 274
 275 static bus_dmamap_t
 276 alloc_dmamap(bus_dma_tag_t dmat, int flags)
 277 {
 278         u_long mapsize;
 279         bus_dmamap_t map;
 280
 281         mapsize = sizeof(*map);
 282         mapsize += sizeof(struct sync_list) * dmat->common.nsegments;
 283         map = malloc(mapsize, M_DEVBUF, flags | M_ZERO);
 284         if (map == NULL)
 285                 return (NULL);
 286
 287         /* Initialize the new map */
 288         STAILQ_INIT(&map->bpages);
 289
 290         return (map);
 291 }
 292
 293 /*
 294  * Allocate a handle for mapping from kva/uva/physical
 295  * address space into bus device space.
 296  */
 297 static int
 298 bounce_bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 299 {
 300         struct bounce_zone *bz;
 301         int error, maxpages, pages;
 302
 303         error = 0;
 304
 305         if (dmat->segments == NULL) {
 306                 dmat->segments = (bus_dma_segment_t *)malloc(
 307                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 308                     M_DEVBUF, M_NOWAIT);
 309                 if (dmat->segments == NULL) {
 310                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 311                             __func__, dmat, ENOMEM);
 312                         return (ENOMEM);
 313                 }
 314         }
 315
 316         *mapp = alloc_dmamap(dmat, M_NOWAIT);
 317         if (*mapp == NULL) {
 318                 CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 319                     __func__, dmat, ENOMEM);
 320                 return (ENOMEM);
 321         }
 322
 323         /*
 324          * Bouncing might be required if the driver asks for an active
 325          * exclusion region, a data alignment that is stricter than 1, and/or
 326          * an active address boundary.
 327          */
 328         if (dmat->bounce_flags & BF_COULD_BOUNCE) {
 329                 /* Must bounce */
 330                 if (dmat->bounce_zone == NULL) {
 331                         if ((error = alloc_bounce_zone(dmat)) != 0) {
 332                                 free(*mapp, M_DEVBUF);
 333                                 return (error);
 334                         }
 335                 }
 336                 bz = dmat->bounce_zone;
 337
 338                 (*mapp)->flags = DMAMAP_COULD_BOUNCE;
 339
 340                 /*
 341                  * Attempt to add pages to our pool on a per-instance
 342                  * basis up to a sane limit.
 343                  */
 344                 if (dmat->common.alignment > 1)
 345                         maxpages = MAX_BPAGES;
 346                 else
 347                         maxpages = MIN(MAX_BPAGES, Maxmem -
 348                             atop(dmat->common.lowaddr));
 349                 if ((dmat->bounce_flags & BF_MIN_ALLOC_COMP) == 0 ||
 350                     (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 351                         pages = MAX(atop(dmat->common.maxsize), 1);
 352                         pages = MIN(maxpages - bz->total_bpages, pages);
 353                         pages = MAX(pages, 1);
 354                         if (alloc_bounce_pages(dmat, pages) < pages)
 355                                 error = ENOMEM;
 356                         if ((dmat->bounce_flags & BF_MIN_ALLOC_COMP)
 357                             == 0) {
 358                                 if (error == 0) {
 359                                         dmat->bounce_flags |=
 360                                             BF_MIN_ALLOC_COMP;
 361                                 }
 362                         } else
 363                                 error = 0;
 364                 }
 365                 bz->map_count++;
 366         }
 367         if (error == 0)
 368                 dmat->map_count++;
 369         else
 370                 free(*mapp, M_DEVBUF);
 371         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 372             __func__, dmat, dmat->common.flags, error);
 373         return (error);
 374 }
 375
 376 /*
 377  * Destroy a handle for mapping from kva/uva/physical
 378  * address space into bus device space.
 379  */
 380 static int
 381 bounce_bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 382 {
 383
 384         /* Check we are destroying the correct map type */
 385         if ((map->flags & DMAMAP_FROM_DMAMEM) != 0)
 386                 panic("bounce_bus_dmamap_destroy: Invalid map freed\n");
 387
 388         if (STAILQ_FIRST(&map->bpages) != NULL || map->sync_count != 0) {
 389                 CTR3(KTR_BUSDMA, "%s: tag %p error %d", __func__, dmat, EBUSY);
 390                 return (EBUSY);
 391         }
 392         if (dmat->bounce_zone) {
 393                 KASSERT((map->flags & DMAMAP_COULD_BOUNCE) != 0,
 394                     ("%s: Bounce zone when cannot bounce", __func__));
 395                 dmat->bounce_zone->map_count--;
 396         }
 397         free(map, M_DEVBUF);
 398         dmat->map_count--;
 399         CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
 400         return (0);
 401 }
 402
 403 /*
 404  * Allocate a piece of memory that can be efficiently mapped into
 405  * bus device space based on the constraints lited in the dma tag.
 406  * A dmamap to for use with dmamap_load is also allocated.
 407  */
 408 static int
 409 bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 410     bus_dmamap_t *mapp)
 411 {
 412         /*
 413          * XXX ARM64TODO:
 414          * This bus_dma implementation requires IO-Coherent architecutre.
 415          * If IO-Coherency is not guaranteed, the BUS_DMA_COHERENT flag has
 416          * to be implented using non-cacheable memory.
 417          */
 418
 419         vm_memattr_t attr;
 420         int mflags;
 421
 422         if (flags & BUS_DMA_NOWAIT)
 423                 mflags = M_NOWAIT;
 424         else
 425                 mflags = M_WAITOK;
 426
 427         if (dmat->segments == NULL) {
 428                 dmat->segments = (bus_dma_segment_t *)malloc(
 429                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 430                     M_DEVBUF, mflags);
 431                 if (dmat->segments == NULL) {
 432                         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 433                             __func__, dmat, dmat->common.flags, ENOMEM);
 434                         return (ENOMEM);
 435                 }
 436         }
 437         if (flags & BUS_DMA_ZERO)
 438                 mflags |= M_ZERO;
 439         if (flags & BUS_DMA_NOCACHE)
 440                 attr = VM_MEMATTR_UNCACHEABLE;
 441         else if ((flags & BUS_DMA_COHERENT) != 0 &&
 442             (dmat->bounce_flags & BF_COHERENT) == 0)
 443                 /*
 444                  * If we have a non-coherent tag, and are trying to allocate
 445                  * a coherent block of memory it needs to be uncached.
 446                  */
 447                 attr = VM_MEMATTR_UNCACHEABLE;
 448         else
 449                 attr = VM_MEMATTR_DEFAULT;
 450
 451         /*
 452          * Create the map, but don't set the could bounce flag as
 453          * this allocation should never bounce;
 454          */
 455         *mapp = alloc_dmamap(dmat, mflags);
 456         if (*mapp == NULL) {
 457                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 458                     __func__, dmat, dmat->common.flags, ENOMEM);
 459                 return (ENOMEM);
 460         }
 461         (*mapp)->flags = DMAMAP_FROM_DMAMEM;
 462
 463         /*
 464          * Allocate the buffer from the malloc(9) allocator if...
 465          *  - It's small enough to fit into a single power of two sized bucket.
 466          *  - The alignment is less than or equal to the maximum size
 467          *  - The low address requirement is fulfilled.
 468          * else allocate non-contiguous pages if...
 469          *  - The page count that could get allocated doesn't exceed
 470          *    nsegments also when the maximum segment size is less
 471          *    than PAGE_SIZE.
 472          *  - The alignment constraint isn't larger than a page boundary.
 473          *  - There are no boundary-crossing constraints.
 474          * else allocate a block of contiguous pages because one or more of the
 475          * constraints is something that only the contig allocator can fulfill.
 476          *
 477          * NOTE: The (dmat->common.alignment <= dmat->maxsize) check
 478          * below is just a quick hack. The exact alignment guarantees
 479          * of malloc(9) need to be nailed down, and the code below
 480          * should be rewritten to take that into account.
 481          *
 482          * In the meantime warn the user if malloc gets it wrong.
 483          */
 484         if ((dmat->common.maxsize <= PAGE_SIZE) &&
 485            (dmat->common.alignment <= dmat->common.maxsize) &&
 486             dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 487             attr == VM_MEMATTR_DEFAULT) {
 488                 *vaddr = malloc(dmat->common.maxsize, M_DEVBUF, mflags);
 489         } else if (dmat->common.nsegments >=
 490             howmany(dmat->common.maxsize, MIN(dmat->common.maxsegsz, PAGE_SIZE)) &&
 491             dmat->common.alignment <= PAGE_SIZE &&
 492             (dmat->common.boundary % PAGE_SIZE) == 0) {
 493                 /* Page-based multi-segment allocations allowed */
 494                 *vaddr = (void *)kmem_alloc_attr(dmat->common.maxsize, mflags,
 495                     0ul, dmat->common.lowaddr, attr);
 496                 dmat->bounce_flags |= BF_KMEM_ALLOC;
 497         } else {
 498                 *vaddr = (void *)kmem_alloc_contig(dmat->common.maxsize, mflags,
 499                     0ul, dmat->common.lowaddr, dmat->common.alignment != 0 ?
 500                     dmat->common.alignment : 1ul, dmat->common.boundary, attr);
 501                 dmat->bounce_flags |= BF_KMEM_ALLOC;
 502         }
 503         if (*vaddr == NULL) {
 504                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 505                     __func__, dmat, dmat->common.flags, ENOMEM);
 506                 free(*mapp, M_DEVBUF);
 507                 return (ENOMEM);
 508         } else if (vtophys(*vaddr) & (dmat->common.alignment - 1)) {
 509                 printf("bus_dmamem_alloc failed to align memory properly.\n");
 510         }
 511         dmat->map_count++;
 512         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 513             __func__, dmat, dmat->common.flags, 0);
 514         return (0);
 515 }
 516
 517 /*
 518  * Free a piece of memory and it's allociated dmamap, that was allocated
 519  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 520  */
 521 static void
 522 bounce_bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 523 {
 524
 525         /*
 526          * Check the map came from bounce_bus_dmamem_alloc, so the map
 527          * should be NULL and the BF_KMEM_ALLOC flag cleared if malloc()
 528          * was used and set if kmem_alloc_contig() was used.
 529          */
 530         if ((map->flags & DMAMAP_FROM_DMAMEM) == 0)
 531                 panic("bus_dmamem_free: Invalid map freed\n");
 532         if ((dmat->bounce_flags & BF_KMEM_ALLOC) == 0)
 533                 free(vaddr, M_DEVBUF);
 534         else
 535                 kmem_free((vm_offset_t)vaddr, dmat->common.maxsize);
 536         free(map, M_DEVBUF);
 537         dmat->map_count--;
 538         CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat,
 539             dmat->bounce_flags);
 540 }
 541
 542 static void
 543 _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
 544     bus_size_t buflen, int flags)
 545 {
 546         bus_addr_t curaddr;
 547         bus_size_t sgsize;
 548
 549         if ((map->flags & DMAMAP_COULD_BOUNCE) != 0 && map->pagesneeded == 0) {
 550                 /*
 551                  * Count the number of bounce pages
 552                  * needed in order to complete this transfer
 553                  */
 554                 curaddr = buf;
 555                 while (buflen != 0) {
 556                         sgsize = MIN(buflen, dmat->common.maxsegsz);
 557                         if (bus_dma_run_filter(&dmat->common, curaddr)) {
 558                                 sgsize = MIN(sgsize,
 559                                     PAGE_SIZE - (curaddr & PAGE_MASK));
 560                                 map->pagesneeded++;
 561                         }
 562                         curaddr += sgsize;
 563                         buflen -= sgsize;
 564                 }
 565                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 566         }
 567 }
 568
 569 static void
 570 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
 571     void *buf, bus_size_t buflen, int flags)
 572 {
 573         vm_offset_t vaddr;
 574         vm_offset_t vendaddr;
 575         bus_addr_t paddr;
 576         bus_size_t sg_len;
 577
 578         if ((map->flags & DMAMAP_COULD_BOUNCE) != 0 && map->pagesneeded == 0) {
 579                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 580                     "alignment= %d", dmat->common.lowaddr,
 581                     ptoa((vm_paddr_t)Maxmem),
 582                     dmat->common.boundary, dmat->common.alignment);
 583                 CTR2(KTR_BUSDMA, "map= %p, pagesneeded= %d", map,
 584                     map->pagesneeded);
 585                 /*
 586                  * Count the number of bounce pages
 587                  * needed in order to complete this transfer
 588                  */
 589                 vaddr = (vm_offset_t)buf;
 590                 vendaddr = (vm_offset_t)buf + buflen;
 591
 592                 while (vaddr < vendaddr) {
 593                         sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
 594                         if (pmap == kernel_pmap)
 595                                 paddr = pmap_kextract(vaddr);
 596                         else
 597                                 paddr = pmap_extract(pmap, vaddr);
 598                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 599                                 sg_len = roundup2(sg_len,
 600                                     dmat->common.alignment);
 601                                 map->pagesneeded++;
 602                         }
 603                         vaddr += sg_len;
 604                 }
 605                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 606         }
 607 }
 608
 609 static int
 610 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
 611 {
 612
 613         /* Reserve Necessary Bounce Pages */
 614         mtx_lock(&bounce_lock);
 615         if (flags & BUS_DMA_NOWAIT) {
 616                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
 617                         mtx_unlock(&bounce_lock);
 618                         return (ENOMEM);
 619                 }
 620         } else {
 621                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
 622                         /* Queue us for resources */
 623                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 624                         mtx_unlock(&bounce_lock);
 625                         return (EINPROGRESS);
 626                 }
 627         }
 628         mtx_unlock(&bounce_lock);
 629
 630         return (0);
 631 }
 632
 633 /*
 634  * Add a single contiguous physical range to the segment list.
 635  */
 636 static bus_size_t
 637 _bus_dmamap_addseg(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t curaddr,
 638     bus_size_t sgsize, bus_dma_segment_t *segs, int *segp)
 639 {
 640         bus_addr_t baddr, bmask;
 641         int seg;
 642
 643         /*
 644          * Make sure we don't cross any boundaries.
 645          */
 646         bmask = ~(dmat->common.boundary - 1);
 647         if (dmat->common.boundary > 0) {
 648                 baddr = (curaddr + dmat->common.boundary) & bmask;
 649                 if (sgsize > (baddr - curaddr))
 650                         sgsize = (baddr - curaddr);
 651         }
 652
 653         /*
 654          * Insert chunk into a segment, coalescing with
 655          * previous segment if possible.
 656          */
 657         seg = *segp;
 658         if (seg == -1) {
 659                 seg = 0;
 660                 segs[seg].ds_addr = curaddr;
 661                 segs[seg].ds_len = sgsize;
 662         } else {
 663                 if (curaddr == segs[seg].ds_addr + segs[seg].ds_len &&
 664                     (segs[seg].ds_len + sgsize) <= dmat->common.maxsegsz &&
 665                     (dmat->common.boundary == 0 ||
 666                      (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 667                         segs[seg].ds_len += sgsize;
 668                 else {
 669                         if (++seg >= dmat->common.nsegments)
 670                                 return (0);
 671                         segs[seg].ds_addr = curaddr;
 672                         segs[seg].ds_len = sgsize;
 673                 }
 674         }
 675         *segp = seg;
 676         return (sgsize);
 677 }
 678
 679 /*
 680  * Utility function to load a physical buffer.  segp contains
 681  * the starting segment on entrace, and the ending segment on exit.
 682  */
 683 static int
 684 bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 685     vm_paddr_t buf, bus_size_t buflen, int flags, bus_dma_segment_t *segs,
 686     int *segp)
 687 {
 688         struct sync_list *sl;
 689         bus_size_t sgsize;
 690         bus_addr_t curaddr, sl_end;
 691         int error;
 692
 693         if (segs == NULL)
 694                 segs = dmat->segments;
 695
 696         if ((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) {
 697                 _bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
 698                 if (map->pagesneeded != 0) {
 699                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 700                         if (error)
 701                                 return (error);
 702                 }
 703         }
 704
 705         sl = map->slist + map->sync_count - 1;
 706         sl_end = 0;
 707
 708         while (buflen > 0) {
 709                 curaddr = buf;
 710                 sgsize = MIN(buflen, dmat->common.maxsegsz);
 711                 if (((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) &&
 712                     map->pagesneeded != 0 &&
 713                     bus_dma_run_filter(&dmat->common, curaddr)) {
 714                         sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
 715                         curaddr = add_bounce_page(dmat, map, 0, curaddr,
 716                             sgsize);
 717                 } else if ((dmat->bounce_flags & BF_COHERENT) == 0) {
 718                         if (map->sync_count > 0)
 719                                 sl_end = sl->paddr + sl->datacount;
 720
 721                         if (map->sync_count == 0 || curaddr != sl_end) {
 722                                 if (++map->sync_count > dmat->common.nsegments)
 723                                         break;
 724                                 sl++;
 725                                 sl->vaddr = 0;
 726                                 sl->paddr = curaddr;
 727                                 sl->datacount = sgsize;
 728                                 sl->pages = PHYS_TO_VM_PAGE(curaddr);
 729                                 KASSERT(sl->pages != NULL,
 730                                     ("%s: page at PA:0x%08lx is not in "
 731                                     "vm_page_array", __func__, curaddr));
 732                         } else
 733                                 sl->datacount += sgsize;
 734                 }
 735                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 736                     segp);
 737                 if (sgsize == 0)
 738                         break;
 739                 buf += sgsize;
 740                 buflen -= sgsize;
 741         }
 742
 743         /*
 744          * Did we fit?
 745          */
 746         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 747 }
 748
 749 /*
 750  * Utility function to load a linear buffer.  segp contains
 751  * the starting segment on entrace, and the ending segment on exit.
 752  */
 753 static int
 754 bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 755     bus_size_t buflen, pmap_t pmap, int flags, bus_dma_segment_t *segs,
 756     int *segp)
 757 {
 758         struct sync_list *sl;
 759         bus_size_t sgsize, max_sgsize;
 760         bus_addr_t curaddr, sl_pend;
 761         vm_offset_t kvaddr, vaddr, sl_vend;
 762         int error;
 763
 764         if (segs == NULL)
 765                 segs = dmat->segments;
 766
 767         if ((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) {
 768                 _bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
 769                 if (map->pagesneeded != 0) {
 770                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 771                         if (error)
 772                                 return (error);
 773                 }
 774         }
 775
 776         sl = map->slist + map->sync_count - 1;
 777         vaddr = (vm_offset_t)buf;
 778         sl_pend = 0;
 779         sl_vend = 0;
 780
 781         while (buflen > 0) {
 782                 /*
 783                  * Get the physical address for this segment.
 784                  */
 785                 if (pmap == kernel_pmap) {
 786                         curaddr = pmap_kextract(vaddr);
 787                         kvaddr = vaddr;
 788                 } else {
 789                         curaddr = pmap_extract(pmap, vaddr);
 790                         kvaddr = 0;
 791                 }
 792
 793                 /*
 794                  * Compute the segment size, and adjust counts.
 795                  */
 796                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 797                 sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
 798                 if (((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) &&
 799                     map->pagesneeded != 0 &&
 800                     bus_dma_run_filter(&dmat->common, curaddr)) {
 801                         sgsize = roundup2(sgsize, dmat->common.alignment);
 802                         sgsize = MIN(sgsize, max_sgsize);
 803                         curaddr = add_bounce_page(dmat, map, kvaddr, curaddr,
 804                             sgsize);
 805                 } else if ((dmat->bounce_flags & BF_COHERENT) == 0) {
 806                         sgsize = MIN(sgsize, max_sgsize);
 807                         if (map->sync_count > 0) {
 808                                 sl_pend = sl->paddr + sl->datacount;
 809                                 sl_vend = sl->vaddr + sl->datacount;
 810                         }
 811
 812                         if (map->sync_count == 0 ||
 813                             (kvaddr != 0 && kvaddr != sl_vend) ||
 814                             (curaddr != sl_pend)) {
 815                                 if (++map->sync_count > dmat->common.nsegments)
 816                                         goto cleanup;
 817                                 sl++;
 818                                 sl->vaddr = kvaddr;
 819                                 sl->paddr = curaddr;
 820                                 if (kvaddr != 0) {
 821                                         sl->pages = NULL;
 822                                 } else {
 823                                         sl->pages = PHYS_TO_VM_PAGE(curaddr);
 824                                         KASSERT(sl->pages != NULL,
 825                                             ("%s: page at PA:0x%08lx is not "
 826                                             "in vm_page_array", __func__,
 827                                             curaddr));
 828                                 }
 829                                 sl->datacount = sgsize;
 830                         } else
 831                                 sl->datacount += sgsize;
 832                 } else {
 833                         sgsize = MIN(sgsize, max_sgsize);
 834                 }
 835                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 836                     segp);
 837                 if (sgsize == 0)
 838                         break;
 839                 vaddr += sgsize;
 840                 buflen -= sgsize;
 841         }
 842
 843 cleanup:
 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->flags & DMAMAP_COULD_BOUNCE) == 0)
 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         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 882                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 883                 free_bounce_page(dmat, bpage);
 884         }
 885
 886         map->sync_count = 0;
 887 }
 888
 889 static void
 890 dma_preread_safe(vm_offset_t va, vm_size_t size)
 891 {
 892         /*
 893          * Write back any partial cachelines immediately before and
 894          * after the DMA region.
 895          */
 896         if (va & (dcache_line_size - 1))
 897                 cpu_dcache_wb_range(va, 1);
 898         if ((va + size) & (dcache_line_size - 1))
 899                 cpu_dcache_wb_range(va + size, 1);
 900
 901         cpu_dcache_inv_range(va, size);
 902 }
 903
 904 static void
 905 dma_dcache_sync(struct sync_list *sl, bus_dmasync_op_t op)
 906 {
 907         uint32_t len, offset;
 908         vm_page_t m;
 909         vm_paddr_t pa;
 910         vm_offset_t va, tempva;
 911         bus_size_t size;
 912
 913         offset = sl->paddr & PAGE_MASK;
 914         m = sl->pages;
 915         size = sl->datacount;
 916         pa = sl->paddr;
 917
 918         for ( ; size != 0; size -= len, pa += len, offset = 0, ++m) {
 919                 tempva = 0;
 920                 if (sl->vaddr == 0) {
 921                         len = min(PAGE_SIZE - offset, size);
 922                         tempva = pmap_quick_enter_page(m);
 923                         va = tempva | offset;
 924                         KASSERT(pa == (VM_PAGE_TO_PHYS(m) | offset),
 925                             ("unexpected vm_page_t phys: 0x%16lx != 0x%16lx",
 926                             VM_PAGE_TO_PHYS(m) | offset, pa));
 927                 } else {
 928                         len = sl->datacount;
 929                         va = sl->vaddr;
 930                 }
 931
 932                 switch (op) {
 933                 case BUS_DMASYNC_PREWRITE:
 934                 case BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD:
 935                         cpu_dcache_wb_range(va, len);
 936                         break;
 937                 case BUS_DMASYNC_PREREAD:
 938                         /*
 939                          * An mbuf may start in the middle of a cacheline. There
 940                          * will be no cpu writes to the beginning of that line
 941                          * (which contains the mbuf header) while dma is in
 942                          * progress.  Handle that case by doing a writeback of
 943                          * just the first cacheline before invalidating the
 944                          * overall buffer.  Any mbuf in a chain may have this
 945                          * misalignment.  Buffers which are not mbufs bounce if
 946                          * they are not aligned to a cacheline.
 947                          */
 948                         dma_preread_safe(va, len);
 949                         break;
 950                 case BUS_DMASYNC_POSTREAD:
 951                 case BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE:
 952                         cpu_dcache_inv_range(va, len);
 953                         break;
 954                 default:
 955                         panic("unsupported combination of sync operations: "
 956                               "0x%08x\n", op);
 957                 }
 958
 959                 if (tempva != 0)
 960                         pmap_quick_remove_page(tempva);
 961         }
 962 }
 963
 964 static void
 965 bounce_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map,
 966     bus_dmasync_op_t op)
 967 {
 968         struct bounce_page *bpage;
 969         struct sync_list *sl, *end;
 970         vm_offset_t datavaddr, tempvaddr;
 971
 972         if (op == BUS_DMASYNC_POSTWRITE)
 973                 return;
 974
 975         if ((op & BUS_DMASYNC_POSTREAD) != 0) {
 976                 /*
 977                  * Wait for any DMA operations to complete before the bcopy.
 978                  */
 979                 fence();
 980         }
 981
 982         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 983                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
 984                     "performing bounce", __func__, dmat, dmat->common.flags,
 985                     op);
 986
 987                 if ((op & BUS_DMASYNC_PREWRITE) != 0) {
 988                         while (bpage != NULL) {
 989                                 tempvaddr = 0;
 990                                 datavaddr = bpage->datavaddr;
 991                                 if (datavaddr == 0) {
 992                                         tempvaddr = pmap_quick_enter_page(
 993                                             bpage->datapage);
 994                                         datavaddr = tempvaddr | bpage->dataoffs;
 995                                 }
 996
 997                                 bcopy((void *)datavaddr,
 998                                     (void *)bpage->vaddr, bpage->datacount);
 999                                 if (tempvaddr != 0)
1000                                         pmap_quick_remove_page(tempvaddr);
1001                                 if ((dmat->bounce_flags & BF_COHERENT) == 0)
1002                                         cpu_dcache_wb_range(bpage->vaddr,
1003                                             bpage->datacount);
1004                                 bpage = STAILQ_NEXT(bpage, links);
1005                         }
1006                         dmat->bounce_zone->total_bounced++;
1007                 } else if ((op & BUS_DMASYNC_PREREAD) != 0) {
1008                         while (bpage != NULL) {
1009                                 if ((dmat->bounce_flags & BF_COHERENT) == 0)
1010                                         cpu_dcache_wbinv_range(bpage->vaddr,
1011                                             bpage->datacount);
1012                                 bpage = STAILQ_NEXT(bpage, links);
1013                         }
1014                 }
1015
1016                 if ((op & BUS_DMASYNC_POSTREAD) != 0) {
1017                         while (bpage != NULL) {
1018                                 if ((dmat->bounce_flags & BF_COHERENT) == 0)
1019                                         cpu_dcache_inv_range(bpage->vaddr,
1020                                             bpage->datacount);
1021                                 tempvaddr = 0;
1022                                 datavaddr = bpage->datavaddr;
1023                                 if (datavaddr == 0) {
1024                                         tempvaddr = pmap_quick_enter_page(
1025                                             bpage->datapage);
1026                                         datavaddr = tempvaddr | bpage->dataoffs;
1027                                 }
1028
1029                                 bcopy((void *)bpage->vaddr,
1030                                     (void *)datavaddr, bpage->datacount);
1031
1032                                 if (tempvaddr != 0)
1033                                         pmap_quick_remove_page(tempvaddr);
1034                                 bpage = STAILQ_NEXT(bpage, links);
1035                         }
1036                         dmat->bounce_zone->total_bounced++;
1037                 }
1038         }
1039
1040         /*
1041          * Cache maintenance for normal (non-COHERENT non-bounce) buffers.
1042          */
1043         if (map->sync_count != 0) {
1044                 sl = &map->slist[0];
1045                 end = &map->slist[map->sync_count];
1046                 CTR3(KTR_BUSDMA, "%s: tag %p op 0x%x "
1047                     "performing sync", __func__, dmat, op);
1048
1049                 for ( ; sl != end; ++sl)
1050                         dma_dcache_sync(sl, op);
1051         }
1052
1053         if ((op & (BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE)) != 0) {
1054                 /*
1055                  * Wait for the bcopy to complete before any DMA operations.
1056                  */
1057                 fence();
1058         }
1059 }
1060
1061 static void
1062 init_bounce_pages(void *dummy __unused)
1063 {
1064
1065         total_bpages = 0;
1066         STAILQ_INIT(&bounce_zone_list);
1067         STAILQ_INIT(&bounce_map_waitinglist);
1068         STAILQ_INIT(&bounce_map_callbacklist);
1069         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
1070 }
1071 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
1072
1073 static struct sysctl_ctx_list *
1074 busdma_sysctl_tree(struct bounce_zone *bz)
1075 {
1076
1077         return (&bz->sysctl_tree);
1078 }
1079
1080 static struct sysctl_oid *
1081 busdma_sysctl_tree_top(struct bounce_zone *bz)
1082 {
1083
1084         return (bz->sysctl_tree_top);
1085 }
1086
1087 static int
1088 alloc_bounce_zone(bus_dma_tag_t dmat)
1089 {
1090         struct bounce_zone *bz;
1091
1092         /* Check to see if we already have a suitable zone */
1093         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1094                 if ((dmat->common.alignment <= bz->alignment) &&
1095                     (dmat->common.lowaddr >= bz->lowaddr)) {
1096                         dmat->bounce_zone = bz;
1097                         return (0);
1098                 }
1099         }
1100
1101         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
1102             M_NOWAIT | M_ZERO)) == NULL)
1103                 return (ENOMEM);
1104
1105         STAILQ_INIT(&bz->bounce_page_list);
1106         bz->free_bpages = 0;
1107         bz->reserved_bpages = 0;
1108         bz->active_bpages = 0;
1109         bz->lowaddr = dmat->common.lowaddr;
1110         bz->alignment = MAX(dmat->common.alignment, PAGE_SIZE);
1111         bz->map_count = 0;
1112         snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1113         busdma_zonecount++;
1114         snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1115         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1116         dmat->bounce_zone = bz;
1117
1118         sysctl_ctx_init(&bz->sysctl_tree);
1119         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
1120             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1121             CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
1122         if (bz->sysctl_tree_top == NULL) {
1123                 sysctl_ctx_free(&bz->sysctl_tree);
1124                 return (0);     /* XXX error code? */
1125         }
1126
1127         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1128             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1129             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1130             "Total bounce pages");
1131         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1132             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1133             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1134             "Free bounce pages");
1135         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1136             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1137             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1138             "Reserved bounce pages");
1139         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1140             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1141             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1142             "Active bounce pages");
1143         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1144             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1145             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1146             "Total bounce requests");
1147         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1148             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1149             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1150             "Total bounce requests that were deferred");
1151         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
1152             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1153             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1154         SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
1155             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1156             "alignment", CTLFLAG_RD, &bz->alignment, "");
1157
1158         return (0);
1159 }
1160
1161 static int
1162 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
1163 {
1164         struct bounce_zone *bz;
1165         int count;
1166
1167         bz = dmat->bounce_zone;
1168         count = 0;
1169         while (numpages > 0) {
1170                 struct bounce_page *bpage;
1171
1172                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
1173                                                      M_NOWAIT | M_ZERO);
1174
1175                 if (bpage == NULL)
1176                         break;
1177                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1178                     M_NOWAIT, 0ul, bz->lowaddr, PAGE_SIZE, 0);
1179                 if (bpage->vaddr == 0) {
1180                         free(bpage, M_DEVBUF);
1181                         break;
1182                 }
1183                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1184                 mtx_lock(&bounce_lock);
1185                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1186                 total_bpages++;
1187                 bz->total_bpages++;
1188                 bz->free_bpages++;
1189                 mtx_unlock(&bounce_lock);
1190                 count++;
1191                 numpages--;
1192         }
1193         return (count);
1194 }
1195
1196 static int
1197 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1198 {
1199         struct bounce_zone *bz;
1200         int pages;
1201
1202         mtx_assert(&bounce_lock, MA_OWNED);
1203         bz = dmat->bounce_zone;
1204         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1205         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
1206                 return (map->pagesneeded - (map->pagesreserved + pages));
1207         bz->free_bpages -= pages;
1208         bz->reserved_bpages += pages;
1209         map->pagesreserved += pages;
1210         pages = map->pagesneeded - map->pagesreserved;
1211
1212         return (pages);
1213 }
1214
1215 static bus_addr_t
1216 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1217                 bus_addr_t addr, bus_size_t size)
1218 {
1219         struct bounce_zone *bz;
1220         struct bounce_page *bpage;
1221
1222         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
1223         KASSERT((map->flags & DMAMAP_COULD_BOUNCE) != 0,
1224             ("add_bounce_page: bad map %p", map));
1225
1226         bz = dmat->bounce_zone;
1227         if (map->pagesneeded == 0)
1228                 panic("add_bounce_page: map doesn't need any pages");
1229         map->pagesneeded--;
1230
1231         if (map->pagesreserved == 0)
1232                 panic("add_bounce_page: map doesn't need any pages");
1233         map->pagesreserved--;
1234
1235         mtx_lock(&bounce_lock);
1236         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1237         if (bpage == NULL)
1238                 panic("add_bounce_page: free page list is empty");
1239
1240         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1241         bz->reserved_bpages--;
1242         bz->active_bpages++;
1243         mtx_unlock(&bounce_lock);
1244
1245         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1246                 /* Page offset needs to be preserved. */
1247                 bpage->vaddr |= addr & PAGE_MASK;
1248                 bpage->busaddr |= addr & PAGE_MASK;
1249         }
1250         bpage->datavaddr = vaddr;
1251         bpage->datapage = PHYS_TO_VM_PAGE(addr);
1252         bpage->dataoffs = addr & PAGE_MASK;
1253         bpage->datacount = size;
1254         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
1255         return (bpage->busaddr);
1256 }
1257
1258 static void
1259 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1260 {
1261         struct bus_dmamap *map;
1262         struct bounce_zone *bz;
1263
1264         bz = dmat->bounce_zone;
1265         bpage->datavaddr = 0;
1266         bpage->datacount = 0;
1267         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1268                 /*
1269                  * Reset the bounce page to start at offset 0.  Other uses
1270                  * of this bounce page may need to store a full page of
1271                  * data and/or assume it starts on a page boundary.
1272                  */
1273                 bpage->vaddr &= ~PAGE_MASK;
1274                 bpage->busaddr &= ~PAGE_MASK;
1275         }
1276
1277         mtx_lock(&bounce_lock);
1278         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1279         bz->free_bpages++;
1280         bz->active_bpages--;
1281         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
1282                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1283                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
1284                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
1285                             map, links);
1286                         busdma_swi_pending = 1;
1287                         bz->total_deferred++;
1288                         swi_sched(vm_ih, 0);
1289                 }
1290         }
1291         mtx_unlock(&bounce_lock);
1292 }
1293
1294 void
1295 busdma_swi(void)
1296 {
1297         bus_dma_tag_t dmat;
1298         struct bus_dmamap *map;
1299
1300         mtx_lock(&bounce_lock);
1301         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1302                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1303                 mtx_unlock(&bounce_lock);
1304                 dmat = map->dmat;
1305                 (dmat->common.lockfunc)(dmat->common.lockfuncarg, BUS_DMA_LOCK);
1306                 bus_dmamap_load_mem(map->dmat, map, &map->mem,
1307                     map->callback, map->callback_arg, BUS_DMA_WAITOK);
1308                 (dmat->common.lockfunc)(dmat->common.lockfuncarg,
1309                     BUS_DMA_UNLOCK);
1310                 mtx_lock(&bounce_lock);
1311         }
1312         mtx_unlock(&bounce_lock);
1313 }
1314
1315 struct bus_dma_impl bus_dma_bounce_impl = {
1316         .tag_create = bounce_bus_dma_tag_create,
1317         .tag_destroy = bounce_bus_dma_tag_destroy,
1318         .map_create = bounce_bus_dmamap_create,
1319         .map_destroy = bounce_bus_dmamap_destroy,
1320         .mem_alloc = bounce_bus_dmamem_alloc,
1321         .mem_free = bounce_bus_dmamem_free,
1322         .load_phys = bounce_bus_dmamap_load_phys,
1323         .load_buffer = bounce_bus_dmamap_load_buffer,
1324         .load_ma = bus_dmamap_load_ma_triv,
1325         .map_waitok = bounce_bus_dmamap_waitok,
1326         .map_complete = bounce_bus_dmamap_complete,
1327         .map_unload = bounce_bus_dmamap_unload,
1328         .map_sync = bounce_bus_dmamap_sync
1329 };