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 struct bounce_zone {
  92         STAILQ_ENTRY(bounce_zone) links;
  93         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  94         int             total_bpages;
  95         int             free_bpages;
  96         int             reserved_bpages;
  97         int             active_bpages;
  98         int             total_bounced;
  99         int             total_deferred;
 100         int             map_count;
 101         bus_size_t      alignment;
 102         bus_addr_t      lowaddr;
 103         char            zoneid[8];
 104         char            lowaddrid[20];
 105         struct sysctl_ctx_list sysctl_tree;
 106         struct sysctl_oid *sysctl_tree_top;
 107 };
 108
 109 static struct mtx bounce_lock;
 110 static int total_bpages;
 111 static int busdma_zonecount;
 112 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
 113 static void *busdma_ih;
 114
 115 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
 116     "Busdma parameters");
 117 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
 118            "Total bounce pages");
 119
 120 struct sync_list {
 121         vm_offset_t     vaddr;          /* kva of client data */
 122         bus_addr_t      paddr;          /* physical address */
 123         vm_page_t       pages;          /* starting page of client data */
 124         bus_size_t      datacount;      /* client data count */
 125 };
 126
 127 struct bus_dmamap {
 128         struct bp_list         bpages;
 129         int                    pagesneeded;
 130         int                    pagesreserved;
 131         bus_dma_tag_t          dmat;
 132         struct memdesc         mem;
 133         bus_dmamap_callback_t *callback;
 134         void                  *callback_arg;
 135         STAILQ_ENTRY(bus_dmamap) links;
 136         u_int                   flags;
 137 #define DMAMAP_COULD_BOUNCE     (1 << 0)
 138 #define DMAMAP_FROM_DMAMEM      (1 << 1)
 139         int                     sync_count;
 140         struct sync_list        slist[];
 141 };
 142
 143 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 144 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
 145
 146 static void init_bounce_pages(void *dummy);
 147 static int alloc_bounce_zone(bus_dma_tag_t dmat);
 148 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 149 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 150     int commit);
 151 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 152     vm_offset_t vaddr, bus_addr_t addr, bus_size_t size);
 153 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 154 int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 155 static void _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 156     pmap_t pmap, void *buf, bus_size_t buflen, int flags);
 157 static void _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 158     vm_paddr_t buf, bus_size_t buflen, int flags);
 159 static int _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 160     int flags);
 161
 162 /*
 163  * Allocate a device specific dma_tag.
 164  */
 165 static int
 166 bounce_bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 167     bus_addr_t boundary, bus_addr_t lowaddr, bus_addr_t highaddr,
 168     bus_dma_filter_t *filter, void *filterarg, bus_size_t maxsize,
 169     int nsegments, bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
 170     void *lockfuncarg, bus_dma_tag_t *dmat)
 171 {
 172         bus_dma_tag_t newtag;
 173         int error;
 174
 175         *dmat = NULL;
 176         error = common_bus_dma_tag_create(parent != NULL ? &parent->common :
 177             NULL, alignment, boundary, lowaddr, highaddr, filter, filterarg,
 178             maxsize, nsegments, maxsegsz, flags, lockfunc, lockfuncarg,
 179             sizeof (struct bus_dma_tag), (void **)&newtag);
 180         if (error != 0)
 181                 return (error);
 182
 183         newtag->common.impl = &bus_dma_bounce_impl;
 184         newtag->map_count = 0;
 185         newtag->segments = NULL;
 186
 187         if ((flags & BUS_DMA_COHERENT) != 0)
 188                 newtag->bounce_flags |= BF_COHERENT;
 189
 190         if (parent != NULL) {
 191                 if ((newtag->common.filter != NULL ||
 192                     (parent->bounce_flags & BF_COULD_BOUNCE) != 0))
 193                         newtag->bounce_flags |= BF_COULD_BOUNCE;
 194
 195                 /* Copy some flags from the parent */
 196                 newtag->bounce_flags |= parent->bounce_flags & BF_COHERENT;
 197         }
 198
 199         if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem) ||
 200             newtag->common.alignment > 1)
 201                 newtag->bounce_flags |= BF_COULD_BOUNCE;
 202
 203         if (((newtag->bounce_flags & BF_COULD_BOUNCE) != 0) &&
 204             (flags & BUS_DMA_ALLOCNOW) != 0) {
 205                 struct bounce_zone *bz;
 206
 207                 /* Must bounce */
 208                 if ((error = alloc_bounce_zone(newtag)) != 0) {
 209                         free(newtag, M_DEVBUF);
 210                         return (error);
 211                 }
 212                 bz = newtag->bounce_zone;
 213
 214                 if (ptoa(bz->total_bpages) < maxsize) {
 215                         int pages;
 216
 217                         pages = atop(round_page(maxsize)) - bz->total_bpages;
 218
 219                         /* Add pages to our bounce pool */
 220                         if (alloc_bounce_pages(newtag, pages) < pages)
 221                                 error = ENOMEM;
 222                 }
 223                 /* Performed initial allocation */
 224                 newtag->bounce_flags |= BF_MIN_ALLOC_COMP;
 225         } else
 226                 error = 0;
 227
 228         if (error != 0)
 229                 free(newtag, M_DEVBUF);
 230         else
 231                 *dmat = newtag;
 232         CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
 233             __func__, newtag, (newtag != NULL ? newtag->common.flags : 0),
 234             error);
 235         return (error);
 236 }
 237
 238 static int
 239 bounce_bus_dma_tag_destroy(bus_dma_tag_t dmat)
 240 {
 241         bus_dma_tag_t dmat_copy, parent;
 242         int error;
 243
 244         error = 0;
 245         dmat_copy = dmat;
 246
 247         if (dmat != NULL) {
 248                 if (dmat->map_count != 0) {
 249                         error = EBUSY;
 250                         goto out;
 251                 }
 252                 while (dmat != NULL) {
 253                         parent = (bus_dma_tag_t)dmat->common.parent;
 254                         atomic_subtract_int(&dmat->common.ref_count, 1);
 255                         if (dmat->common.ref_count == 0) {
 256                                 if (dmat->segments != NULL)
 257                                         free(dmat->segments, M_DEVBUF);
 258                                 free(dmat, M_DEVBUF);
 259                                 /*
 260                                  * Last reference count, so
 261                                  * release our reference
 262                                  * count on our parent.
 263                                  */
 264                                 dmat = parent;
 265                         } else
 266                                 dmat = NULL;
 267                 }
 268         }
 269 out:
 270         CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
 271         return (error);
 272 }
 273
 274 static bus_dmamap_t
 275 alloc_dmamap(bus_dma_tag_t dmat, int flags)
 276 {
 277         u_long mapsize;
 278         bus_dmamap_t map;
 279
 280         mapsize = sizeof(*map);
 281         mapsize += sizeof(struct sync_list) * dmat->common.nsegments;
 282         map = malloc(mapsize, M_DEVBUF, flags | M_ZERO);
 283         if (map == NULL)
 284                 return (NULL);
 285
 286         /* Initialize the new map */
 287         STAILQ_INIT(&map->bpages);
 288
 289         return (map);
 290 }
 291
 292 /*
 293  * Allocate a handle for mapping from kva/uva/physical
 294  * address space into bus device space.
 295  */
 296 static int
 297 bounce_bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 298 {
 299         struct bounce_zone *bz;
 300         int error, maxpages, pages;
 301
 302         error = 0;
 303
 304         if (dmat->segments == NULL) {
 305                 dmat->segments = (bus_dma_segment_t *)malloc(
 306                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 307                     M_DEVBUF, M_NOWAIT);
 308                 if (dmat->segments == NULL) {
 309                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 310                             __func__, dmat, ENOMEM);
 311                         return (ENOMEM);
 312                 }
 313         }
 314
 315         *mapp = alloc_dmamap(dmat, M_NOWAIT);
 316         if (*mapp == NULL) {
 317                 CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 318                     __func__, dmat, ENOMEM);
 319                 return (ENOMEM);
 320         }
 321
 322         /*
 323          * Bouncing might be required if the driver asks for an active
 324          * exclusion region, a data alignment that is stricter than 1, and/or
 325          * an active address boundary.
 326          */
 327         if (dmat->bounce_flags & BF_COULD_BOUNCE) {
 328                 /* Must bounce */
 329                 if (dmat->bounce_zone == NULL) {
 330                         if ((error = alloc_bounce_zone(dmat)) != 0) {
 331                                 free(*mapp, M_DEVBUF);
 332                                 return (error);
 333                         }
 334                 }
 335                 bz = dmat->bounce_zone;
 336
 337                 (*mapp)->flags = DMAMAP_COULD_BOUNCE;
 338
 339                 /*
 340                  * Attempt to add pages to our pool on a per-instance
 341                  * basis up to a sane limit.
 342                  */
 343                 if (dmat->common.alignment > 1)
 344                         maxpages = MAX_BPAGES;
 345                 else
 346                         maxpages = MIN(MAX_BPAGES, Maxmem -
 347                             atop(dmat->common.lowaddr));
 348                 if ((dmat->bounce_flags & BF_MIN_ALLOC_COMP) == 0 ||
 349                     (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 350                         pages = MAX(atop(dmat->common.maxsize), 1);
 351                         pages = MIN(maxpages - bz->total_bpages, pages);
 352                         pages = MAX(pages, 1);
 353                         if (alloc_bounce_pages(dmat, pages) < pages)
 354                                 error = ENOMEM;
 355                         if ((dmat->bounce_flags & BF_MIN_ALLOC_COMP)
 356                             == 0) {
 357                                 if (error == 0) {
 358                                         dmat->bounce_flags |=
 359                                             BF_MIN_ALLOC_COMP;
 360                                 }
 361                         } else
 362                                 error = 0;
 363                 }
 364                 bz->map_count++;
 365         }
 366         if (error == 0)
 367                 dmat->map_count++;
 368         else
 369                 free(*mapp, M_DEVBUF);
 370         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 371             __func__, dmat, dmat->common.flags, error);
 372         return (error);
 373 }
 374
 375 /*
 376  * Destroy a handle for mapping from kva/uva/physical
 377  * address space into bus device space.
 378  */
 379 static int
 380 bounce_bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 381 {
 382
 383         /* Check we are destroying the correct map type */
 384         if ((map->flags & DMAMAP_FROM_DMAMEM) != 0)
 385                 panic("bounce_bus_dmamap_destroy: Invalid map freed\n");
 386
 387         if (STAILQ_FIRST(&map->bpages) != NULL || map->sync_count != 0) {
 388                 CTR3(KTR_BUSDMA, "%s: tag %p error %d", __func__, dmat, EBUSY);
 389                 return (EBUSY);
 390         }
 391         if (dmat->bounce_zone) {
 392                 KASSERT((map->flags & DMAMAP_COULD_BOUNCE) != 0,
 393                     ("%s: Bounce zone when cannot bounce", __func__));
 394                 dmat->bounce_zone->map_count--;
 395         }
 396         free(map, M_DEVBUF);
 397         dmat->map_count--;
 398         CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
 399         return (0);
 400 }
 401
 402 /*
 403  * Allocate a piece of memory that can be efficiently mapped into
 404  * bus device space based on the constraints lited in the dma tag.
 405  * A dmamap to for use with dmamap_load is also allocated.
 406  */
 407 static int
 408 bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 409     bus_dmamap_t *mapp)
 410 {
 411         /*
 412          * XXX ARM64TODO:
 413          * This bus_dma implementation requires IO-Coherent architecutre.
 414          * If IO-Coherency is not guaranteed, the BUS_DMA_COHERENT flag has
 415          * to be implented using non-cacheable memory.
 416          */
 417
 418         vm_memattr_t attr;
 419         int mflags;
 420
 421         if (flags & BUS_DMA_NOWAIT)
 422                 mflags = M_NOWAIT;
 423         else
 424                 mflags = M_WAITOK;
 425
 426         if (dmat->segments == NULL) {
 427                 dmat->segments = (bus_dma_segment_t *)malloc(
 428                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 429                     M_DEVBUF, mflags);
 430                 if (dmat->segments == NULL) {
 431                         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 432                             __func__, dmat, dmat->common.flags, ENOMEM);
 433                         return (ENOMEM);
 434                 }
 435         }
 436         if (flags & BUS_DMA_ZERO)
 437                 mflags |= M_ZERO;
 438         if (flags & BUS_DMA_NOCACHE)
 439                 attr = VM_MEMATTR_UNCACHEABLE;
 440         else if ((flags & BUS_DMA_COHERENT) != 0 &&
 441             (dmat->bounce_flags & BF_COHERENT) == 0)
 442                 /*
 443                  * If we have a non-coherent tag, and are trying to allocate
 444                  * a coherent block of memory it needs to be uncached.
 445                  */
 446                 attr = VM_MEMATTR_UNCACHEABLE;
 447         else
 448                 attr = VM_MEMATTR_DEFAULT;
 449
 450         /*
 451          * Create the map, but don't set the could bounce flag as
 452          * this allocation should never bounce;
 453          */
 454         *mapp = alloc_dmamap(dmat, mflags);
 455         if (*mapp == NULL) {
 456                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 457                     __func__, dmat, dmat->common.flags, ENOMEM);
 458                 return (ENOMEM);
 459         }
 460         (*mapp)->flags = DMAMAP_FROM_DMAMEM;
 461
 462         /*
 463          * Allocate the buffer from the malloc(9) allocator if...
 464          *  - It's small enough to fit into a single power of two sized bucket.
 465          *  - The alignment is less than or equal to the maximum size
 466          *  - The low address requirement is fulfilled.
 467          * else allocate non-contiguous pages if...
 468          *  - The page count that could get allocated doesn't exceed
 469          *    nsegments also when the maximum segment size is less
 470          *    than PAGE_SIZE.
 471          *  - The alignment constraint isn't larger than a page boundary.
 472          *  - There are no boundary-crossing constraints.
 473          * else allocate a block of contiguous pages because one or more of the
 474          * constraints is something that only the contig allocator can fulfill.
 475          *
 476          * NOTE: The (dmat->common.alignment <= dmat->maxsize) check
 477          * below is just a quick hack. The exact alignment guarantees
 478          * of malloc(9) need to be nailed down, and the code below
 479          * should be rewritten to take that into account.
 480          *
 481          * In the meantime warn the user if malloc gets it wrong.
 482          */
 483         if ((dmat->common.maxsize <= PAGE_SIZE) &&
 484            (dmat->common.alignment <= dmat->common.maxsize) &&
 485             dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 486             attr == VM_MEMATTR_DEFAULT) {
 487                 *vaddr = malloc(dmat->common.maxsize, M_DEVBUF, mflags);
 488         } else if (dmat->common.nsegments >=
 489             howmany(dmat->common.maxsize, MIN(dmat->common.maxsegsz, PAGE_SIZE)) &&
 490             dmat->common.alignment <= PAGE_SIZE &&
 491             (dmat->common.boundary % PAGE_SIZE) == 0) {
 492                 /* Page-based multi-segment allocations allowed */
 493                 *vaddr = (void *)kmem_alloc_attr(dmat->common.maxsize, mflags,
 494                     0ul, dmat->common.lowaddr, attr);
 495                 dmat->bounce_flags |= BF_KMEM_ALLOC;
 496         } else {
 497                 *vaddr = (void *)kmem_alloc_contig(dmat->common.maxsize, mflags,
 498                     0ul, dmat->common.lowaddr, dmat->common.alignment != 0 ?
 499                     dmat->common.alignment : 1ul, dmat->common.boundary, attr);
 500                 dmat->bounce_flags |= BF_KMEM_ALLOC;
 501         }
 502         if (*vaddr == NULL) {
 503                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 504                     __func__, dmat, dmat->common.flags, ENOMEM);
 505                 free(*mapp, M_DEVBUF);
 506                 return (ENOMEM);
 507         } else if (!vm_addr_align_ok(vtophys(*vaddr), dmat->common.alignment)) {
 508                 printf("bus_dmamem_alloc failed to align memory properly.\n");
 509         }
 510         dmat->map_count++;
 511         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 512             __func__, dmat, dmat->common.flags, 0);
 513         return (0);
 514 }
 515
 516 /*
 517  * Free a piece of memory and it's allociated dmamap, that was allocated
 518  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 519  */
 520 static void
 521 bounce_bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 522 {
 523
 524         /*
 525          * Check the map came from bounce_bus_dmamem_alloc, so the map
 526          * should be NULL and the BF_KMEM_ALLOC flag cleared if malloc()
 527          * was used and set if kmem_alloc_contig() was used.
 528          */
 529         if ((map->flags & DMAMAP_FROM_DMAMEM) == 0)
 530                 panic("bus_dmamem_free: Invalid map freed\n");
 531         if ((dmat->bounce_flags & BF_KMEM_ALLOC) == 0)
 532                 free(vaddr, M_DEVBUF);
 533         else
 534                 kmem_free((vm_offset_t)vaddr, dmat->common.maxsize);
 535         free(map, M_DEVBUF);
 536         dmat->map_count--;
 537         CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat,
 538             dmat->bounce_flags);
 539 }
 540
 541 static void
 542 _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
 543     bus_size_t buflen, int flags)
 544 {
 545         bus_addr_t curaddr;
 546         bus_size_t sgsize;
 547
 548         if ((map->flags & DMAMAP_COULD_BOUNCE) != 0 && map->pagesneeded == 0) {
 549                 /*
 550                  * Count the number of bounce pages
 551                  * needed in order to complete this transfer
 552                  */
 553                 curaddr = buf;
 554                 while (buflen != 0) {
 555                         sgsize = MIN(buflen, dmat->common.maxsegsz);
 556                         if (bus_dma_run_filter(&dmat->common, curaddr)) {
 557                                 sgsize = MIN(sgsize,
 558                                     PAGE_SIZE - (curaddr & PAGE_MASK));
 559                                 map->pagesneeded++;
 560                         }
 561                         curaddr += sgsize;
 562                         buflen -= sgsize;
 563                 }
 564                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 565         }
 566 }
 567
 568 static void
 569 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
 570     void *buf, bus_size_t buflen, int flags)
 571 {
 572         vm_offset_t vaddr;
 573         vm_offset_t vendaddr;
 574         bus_addr_t paddr;
 575         bus_size_t sg_len;
 576
 577         if ((map->flags & DMAMAP_COULD_BOUNCE) != 0 && map->pagesneeded == 0) {
 578                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 579                     "alignment= %d", dmat->common.lowaddr,
 580                     ptoa((vm_paddr_t)Maxmem),
 581                     dmat->common.boundary, dmat->common.alignment);
 582                 CTR2(KTR_BUSDMA, "map= %p, pagesneeded= %d", map,
 583                     map->pagesneeded);
 584                 /*
 585                  * Count the number of bounce pages
 586                  * needed in order to complete this transfer
 587                  */
 588                 vaddr = (vm_offset_t)buf;
 589                 vendaddr = (vm_offset_t)buf + buflen;
 590
 591                 while (vaddr < vendaddr) {
 592                         sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
 593                         if (pmap == kernel_pmap)
 594                                 paddr = pmap_kextract(vaddr);
 595                         else
 596                                 paddr = pmap_extract(pmap, vaddr);
 597                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 598                                 sg_len = roundup2(sg_len,
 599                                     dmat->common.alignment);
 600                                 map->pagesneeded++;
 601                         }
 602                         vaddr += sg_len;
 603                 }
 604                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 605         }
 606 }
 607
 608 static int
 609 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
 610 {
 611
 612         /* Reserve Necessary Bounce Pages */
 613         mtx_lock(&bounce_lock);
 614         if (flags & BUS_DMA_NOWAIT) {
 615                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
 616                         mtx_unlock(&bounce_lock);
 617                         return (ENOMEM);
 618                 }
 619         } else {
 620                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
 621                         /* Queue us for resources */
 622                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 623                         mtx_unlock(&bounce_lock);
 624                         return (EINPROGRESS);
 625                 }
 626         }
 627         mtx_unlock(&bounce_lock);
 628
 629         return (0);
 630 }
 631
 632 /*
 633  * Add a single contiguous physical range to the segment list.
 634  */
 635 static bus_size_t
 636 _bus_dmamap_addseg(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t curaddr,
 637     bus_size_t sgsize, bus_dma_segment_t *segs, int *segp)
 638 {
 639         int seg;
 640
 641         /*
 642          * Make sure we don't cross any boundaries.
 643          */
 644         if (!vm_addr_bound_ok(curaddr, sgsize, dmat->common.boundary))
 645                 sgsize = roundup2(curaddr, dmat->common.boundary) - curaddr;
 646
 647         /*
 648          * Insert chunk into a segment, coalescing with
 649          * previous segment if possible.
 650          */
 651         seg = *segp;
 652         if (seg == -1) {
 653                 seg = 0;
 654                 segs[seg].ds_addr = curaddr;
 655                 segs[seg].ds_len = sgsize;
 656         } else {
 657                 if (curaddr == segs[seg].ds_addr + segs[seg].ds_len &&
 658                     (segs[seg].ds_len + sgsize) <= dmat->common.maxsegsz &&
 659                     vm_addr_bound_ok(segs[seg].ds_addr,
 660                     segs[seg].ds_len + sgsize, dmat->common.boundary))
 661                         segs[seg].ds_len += sgsize;
 662                 else {
 663                         if (++seg >= dmat->common.nsegments)
 664                                 return (0);
 665                         segs[seg].ds_addr = curaddr;
 666                         segs[seg].ds_len = sgsize;
 667                 }
 668         }
 669         *segp = seg;
 670         return (sgsize);
 671 }
 672
 673 /*
 674  * Utility function to load a physical buffer.  segp contains
 675  * the starting segment on entrace, and the ending segment on exit.
 676  */
 677 static int
 678 bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 679     vm_paddr_t buf, bus_size_t buflen, int flags, bus_dma_segment_t *segs,
 680     int *segp)
 681 {
 682         struct sync_list *sl;
 683         bus_size_t sgsize;
 684         bus_addr_t curaddr, sl_end;
 685         int error;
 686
 687         if (segs == NULL)
 688                 segs = dmat->segments;
 689
 690         if ((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) {
 691                 _bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
 692                 if (map->pagesneeded != 0) {
 693                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 694                         if (error)
 695                                 return (error);
 696                 }
 697         }
 698
 699         sl = map->slist + map->sync_count - 1;
 700         sl_end = 0;
 701
 702         while (buflen > 0) {
 703                 curaddr = buf;
 704                 sgsize = MIN(buflen, dmat->common.maxsegsz);
 705                 if (((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) &&
 706                     map->pagesneeded != 0 &&
 707                     bus_dma_run_filter(&dmat->common, curaddr)) {
 708                         sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
 709                         curaddr = add_bounce_page(dmat, map, 0, curaddr,
 710                             sgsize);
 711                 } else if ((dmat->bounce_flags & BF_COHERENT) == 0) {
 712                         if (map->sync_count > 0)
 713                                 sl_end = sl->paddr + sl->datacount;
 714
 715                         if (map->sync_count == 0 || curaddr != sl_end) {
 716                                 if (++map->sync_count > dmat->common.nsegments)
 717                                         break;
 718                                 sl++;
 719                                 sl->vaddr = 0;
 720                                 sl->paddr = curaddr;
 721                                 sl->datacount = sgsize;
 722                                 sl->pages = PHYS_TO_VM_PAGE(curaddr);
 723                                 KASSERT(sl->pages != NULL,
 724                                     ("%s: page at PA:0x%08lx is not in "
 725                                     "vm_page_array", __func__, curaddr));
 726                         } else
 727                                 sl->datacount += sgsize;
 728                 }
 729                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 730                     segp);
 731                 if (sgsize == 0)
 732                         break;
 733                 buf += sgsize;
 734                 buflen -= sgsize;
 735         }
 736
 737         /*
 738          * Did we fit?
 739          */
 740         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 741 }
 742
 743 /*
 744  * Utility function to load a linear buffer.  segp contains
 745  * the starting segment on entrace, and the ending segment on exit.
 746  */
 747 static int
 748 bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 749     bus_size_t buflen, pmap_t pmap, int flags, bus_dma_segment_t *segs,
 750     int *segp)
 751 {
 752         struct sync_list *sl;
 753         bus_size_t sgsize, max_sgsize;
 754         bus_addr_t curaddr, sl_pend;
 755         vm_offset_t kvaddr, vaddr, sl_vend;
 756         int error;
 757
 758         if (segs == NULL)
 759                 segs = dmat->segments;
 760
 761         if ((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) {
 762                 _bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
 763                 if (map->pagesneeded != 0) {
 764                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 765                         if (error)
 766                                 return (error);
 767                 }
 768         }
 769
 770         sl = map->slist + map->sync_count - 1;
 771         vaddr = (vm_offset_t)buf;
 772         sl_pend = 0;
 773         sl_vend = 0;
 774
 775         while (buflen > 0) {
 776                 /*
 777                  * Get the physical address for this segment.
 778                  */
 779                 if (pmap == kernel_pmap) {
 780                         curaddr = pmap_kextract(vaddr);
 781                         kvaddr = vaddr;
 782                 } else {
 783                         curaddr = pmap_extract(pmap, vaddr);
 784                         kvaddr = 0;
 785                 }
 786
 787                 /*
 788                  * Compute the segment size, and adjust counts.
 789                  */
 790                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 791                 sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
 792                 if (((dmat->bounce_flags & BF_COULD_BOUNCE) != 0) &&
 793                     map->pagesneeded != 0 &&
 794                     bus_dma_run_filter(&dmat->common, curaddr)) {
 795                         sgsize = roundup2(sgsize, dmat->common.alignment);
 796                         sgsize = MIN(sgsize, max_sgsize);
 797                         curaddr = add_bounce_page(dmat, map, kvaddr, curaddr,
 798                             sgsize);
 799                 } else if ((dmat->bounce_flags & BF_COHERENT) == 0) {
 800                         sgsize = MIN(sgsize, max_sgsize);
 801                         if (map->sync_count > 0) {
 802                                 sl_pend = sl->paddr + sl->datacount;
 803                                 sl_vend = sl->vaddr + sl->datacount;
 804                         }
 805
 806                         if (map->sync_count == 0 ||
 807                             (kvaddr != 0 && kvaddr != sl_vend) ||
 808                             (curaddr != sl_pend)) {
 809                                 if (++map->sync_count > dmat->common.nsegments)
 810                                         goto cleanup;
 811                                 sl++;
 812                                 sl->vaddr = kvaddr;
 813                                 sl->paddr = curaddr;
 814                                 if (kvaddr != 0) {
 815                                         sl->pages = NULL;
 816                                 } else {
 817                                         sl->pages = PHYS_TO_VM_PAGE(curaddr);
 818                                         KASSERT(sl->pages != NULL,
 819                                             ("%s: page at PA:0x%08lx is not "
 820                                             "in vm_page_array", __func__,
 821                                             curaddr));
 822                                 }
 823                                 sl->datacount = sgsize;
 824                         } else
 825                                 sl->datacount += sgsize;
 826                 } else {
 827                         sgsize = MIN(sgsize, max_sgsize);
 828                 }
 829                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 830                     segp);
 831                 if (sgsize == 0)
 832                         break;
 833                 vaddr += sgsize;
 834                 buflen -= sgsize;
 835         }
 836
 837 cleanup:
 838         /*
 839          * Did we fit?
 840          */
 841         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 842 }
 843
 844 static void
 845 bounce_bus_dmamap_waitok(bus_dma_tag_t dmat, bus_dmamap_t map,
 846     struct memdesc *mem, bus_dmamap_callback_t *callback, void *callback_arg)
 847 {
 848
 849         if ((map->flags & DMAMAP_COULD_BOUNCE) == 0)
 850                 return;
 851         map->mem = *mem;
 852         map->dmat = dmat;
 853         map->callback = callback;
 854         map->callback_arg = callback_arg;
 855 }
 856
 857 static bus_dma_segment_t *
 858 bounce_bus_dmamap_complete(bus_dma_tag_t dmat, bus_dmamap_t map,
 859     bus_dma_segment_t *segs, int nsegs, int error)
 860 {
 861
 862         if (segs == NULL)
 863                 segs = dmat->segments;
 864         return (segs);
 865 }
 866
 867 /*
 868  * Release the mapping held by map.
 869  */
 870 static void
 871 bounce_bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 872 {
 873         struct bounce_page *bpage;
 874
 875         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 876                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 877                 free_bounce_page(dmat, bpage);
 878         }
 879
 880         map->sync_count = 0;
 881 }
 882
 883 static void
 884 dma_preread_safe(vm_offset_t va, vm_size_t size)
 885 {
 886         /*
 887          * Write back any partial cachelines immediately before and
 888          * after the DMA region.
 889          */
 890         if (va & (dcache_line_size - 1))
 891                 cpu_dcache_wb_range(va, 1);
 892         if ((va + size) & (dcache_line_size - 1))
 893                 cpu_dcache_wb_range(va + size, 1);
 894
 895         cpu_dcache_inv_range(va, size);
 896 }
 897
 898 static void
 899 dma_dcache_sync(struct sync_list *sl, bus_dmasync_op_t op)
 900 {
 901         uint32_t len, offset;
 902         vm_page_t m;
 903         vm_paddr_t pa;
 904         vm_offset_t va, tempva;
 905         bus_size_t size;
 906
 907         offset = sl->paddr & PAGE_MASK;
 908         m = sl->pages;
 909         size = sl->datacount;
 910         pa = sl->paddr;
 911
 912         for ( ; size != 0; size -= len, pa += len, offset = 0, ++m) {
 913                 tempva = 0;
 914                 if (sl->vaddr == 0) {
 915                         len = min(PAGE_SIZE - offset, size);
 916                         tempva = pmap_quick_enter_page(m);
 917                         va = tempva | offset;
 918                         KASSERT(pa == (VM_PAGE_TO_PHYS(m) | offset),
 919                             ("unexpected vm_page_t phys: 0x%16lx != 0x%16lx",
 920                             VM_PAGE_TO_PHYS(m) | offset, pa));
 921                 } else {
 922                         len = sl->datacount;
 923                         va = sl->vaddr;
 924                 }
 925
 926                 switch (op) {
 927                 case BUS_DMASYNC_PREWRITE:
 928                 case BUS_DMASYNC_PREWRITE | BUS_DMASYNC_PREREAD:
 929                         cpu_dcache_wb_range(va, len);
 930                         break;
 931                 case BUS_DMASYNC_PREREAD:
 932                         /*
 933                          * An mbuf may start in the middle of a cacheline. There
 934                          * will be no cpu writes to the beginning of that line
 935                          * (which contains the mbuf header) while dma is in
 936                          * progress.  Handle that case by doing a writeback of
 937                          * just the first cacheline before invalidating the
 938                          * overall buffer.  Any mbuf in a chain may have this
 939                          * misalignment.  Buffers which are not mbufs bounce if
 940                          * they are not aligned to a cacheline.
 941                          */
 942                         dma_preread_safe(va, len);
 943                         break;
 944                 case BUS_DMASYNC_POSTREAD:
 945                 case BUS_DMASYNC_POSTREAD | BUS_DMASYNC_POSTWRITE:
 946                         cpu_dcache_inv_range(va, len);
 947                         break;
 948                 default:
 949                         panic("unsupported combination of sync operations: "
 950                               "0x%08x\n", op);
 951                 }
 952
 953                 if (tempva != 0)
 954                         pmap_quick_remove_page(tempva);
 955         }
 956 }
 957
 958 static void
 959 bounce_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map,
 960     bus_dmasync_op_t op)
 961 {
 962         struct bounce_page *bpage;
 963         struct sync_list *sl, *end;
 964         vm_offset_t datavaddr, tempvaddr;
 965
 966         if (op == BUS_DMASYNC_POSTWRITE)
 967                 return;
 968
 969         if ((op & BUS_DMASYNC_POSTREAD) != 0) {
 970                 /*
 971                  * Wait for any DMA operations to complete before the bcopy.
 972                  */
 973                 fence();
 974         }
 975
 976         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 977                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
 978                     "performing bounce", __func__, dmat, dmat->common.flags,
 979                     op);
 980
 981                 if ((op & BUS_DMASYNC_PREWRITE) != 0) {
 982                         while (bpage != NULL) {
 983                                 tempvaddr = 0;
 984                                 datavaddr = bpage->datavaddr;
 985                                 if (datavaddr == 0) {
 986                                         tempvaddr = pmap_quick_enter_page(
 987                                             bpage->datapage);
 988                                         datavaddr = tempvaddr | bpage->dataoffs;
 989                                 }
 990
 991                                 bcopy((void *)datavaddr,
 992                                     (void *)bpage->vaddr, bpage->datacount);
 993                                 if (tempvaddr != 0)
 994                                         pmap_quick_remove_page(tempvaddr);
 995                                 if ((dmat->bounce_flags & BF_COHERENT) == 0)
 996                                         cpu_dcache_wb_range(bpage->vaddr,
 997                                             bpage->datacount);
 998                                 bpage = STAILQ_NEXT(bpage, links);
 999                         }
1000                         dmat->bounce_zone->total_bounced++;
1001                 } else if ((op & BUS_DMASYNC_PREREAD) != 0) {
1002                         while (bpage != NULL) {
1003                                 if ((dmat->bounce_flags & BF_COHERENT) == 0)
1004                                         cpu_dcache_wbinv_range(bpage->vaddr,
1005                                             bpage->datacount);
1006                                 bpage = STAILQ_NEXT(bpage, links);
1007                         }
1008                 }
1009
1010                 if ((op & BUS_DMASYNC_POSTREAD) != 0) {
1011                         while (bpage != NULL) {
1012                                 if ((dmat->bounce_flags & BF_COHERENT) == 0)
1013                                         cpu_dcache_inv_range(bpage->vaddr,
1014                                             bpage->datacount);
1015                                 tempvaddr = 0;
1016                                 datavaddr = bpage->datavaddr;
1017                                 if (datavaddr == 0) {
1018                                         tempvaddr = pmap_quick_enter_page(
1019                                             bpage->datapage);
1020                                         datavaddr = tempvaddr | bpage->dataoffs;
1021                                 }
1022
1023                                 bcopy((void *)bpage->vaddr,
1024                                     (void *)datavaddr, bpage->datacount);
1025
1026                                 if (tempvaddr != 0)
1027                                         pmap_quick_remove_page(tempvaddr);
1028                                 bpage = STAILQ_NEXT(bpage, links);
1029                         }
1030                         dmat->bounce_zone->total_bounced++;
1031                 }
1032         }
1033
1034         /*
1035          * Cache maintenance for normal (non-COHERENT non-bounce) buffers.
1036          */
1037         if (map->sync_count != 0) {
1038                 sl = &map->slist[0];
1039                 end = &map->slist[map->sync_count];
1040                 CTR3(KTR_BUSDMA, "%s: tag %p op 0x%x "
1041                     "performing sync", __func__, dmat, op);
1042
1043                 for ( ; sl != end; ++sl)
1044                         dma_dcache_sync(sl, op);
1045         }
1046
1047         if ((op & (BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE)) != 0) {
1048                 /*
1049                  * Wait for the bcopy to complete before any DMA operations.
1050                  */
1051                 fence();
1052         }
1053 }
1054
1055 static void
1056 init_bounce_pages(void *dummy __unused)
1057 {
1058
1059         total_bpages = 0;
1060         STAILQ_INIT(&bounce_zone_list);
1061         STAILQ_INIT(&bounce_map_waitinglist);
1062         STAILQ_INIT(&bounce_map_callbacklist);
1063         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
1064 }
1065 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
1066
1067 static struct sysctl_ctx_list *
1068 busdma_sysctl_tree(struct bounce_zone *bz)
1069 {
1070
1071         return (&bz->sysctl_tree);
1072 }
1073
1074 static struct sysctl_oid *
1075 busdma_sysctl_tree_top(struct bounce_zone *bz)
1076 {
1077
1078         return (bz->sysctl_tree_top);
1079 }
1080
1081 static int
1082 alloc_bounce_zone(bus_dma_tag_t dmat)
1083 {
1084         struct bounce_zone *bz;
1085
1086         /* Check to see if we already have a suitable zone */
1087         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1088                 if ((dmat->common.alignment <= bz->alignment) &&
1089                     (dmat->common.lowaddr >= bz->lowaddr)) {
1090                         dmat->bounce_zone = bz;
1091                         return (0);
1092                 }
1093         }
1094
1095         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
1096             M_NOWAIT | M_ZERO)) == NULL)
1097                 return (ENOMEM);
1098
1099         STAILQ_INIT(&bz->bounce_page_list);
1100         bz->free_bpages = 0;
1101         bz->reserved_bpages = 0;
1102         bz->active_bpages = 0;
1103         bz->lowaddr = dmat->common.lowaddr;
1104         bz->alignment = MAX(dmat->common.alignment, PAGE_SIZE);
1105         bz->map_count = 0;
1106         snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1107         busdma_zonecount++;
1108         snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1109         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1110         dmat->bounce_zone = bz;
1111
1112         sysctl_ctx_init(&bz->sysctl_tree);
1113         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
1114             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1115             CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
1116         if (bz->sysctl_tree_top == NULL) {
1117                 sysctl_ctx_free(&bz->sysctl_tree);
1118                 return (0);     /* XXX error code? */
1119         }
1120
1121         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1122             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1123             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1124             "Total bounce pages");
1125         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1126             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1127             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1128             "Free bounce pages");
1129         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1130             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1131             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1132             "Reserved bounce pages");
1133         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1134             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1135             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1136             "Active bounce pages");
1137         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1138             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1139             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1140             "Total bounce requests");
1141         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1142             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1143             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1144             "Total bounce requests that were deferred");
1145         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
1146             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1147             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1148         SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
1149             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1150             "alignment", CTLFLAG_RD, &bz->alignment, "");
1151
1152         return (0);
1153 }
1154
1155 static int
1156 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
1157 {
1158         struct bounce_zone *bz;
1159         int count;
1160
1161         bz = dmat->bounce_zone;
1162         count = 0;
1163         while (numpages > 0) {
1164                 struct bounce_page *bpage;
1165
1166                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
1167                                                      M_NOWAIT | M_ZERO);
1168
1169                 if (bpage == NULL)
1170                         break;
1171                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1172                     M_NOWAIT, 0ul, bz->lowaddr, PAGE_SIZE, 0);
1173                 if (bpage->vaddr == 0) {
1174                         free(bpage, M_DEVBUF);
1175                         break;
1176                 }
1177                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1178                 mtx_lock(&bounce_lock);
1179                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1180                 total_bpages++;
1181                 bz->total_bpages++;
1182                 bz->free_bpages++;
1183                 mtx_unlock(&bounce_lock);
1184                 count++;
1185                 numpages--;
1186         }
1187         return (count);
1188 }
1189
1190 static int
1191 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1192 {
1193         struct bounce_zone *bz;
1194         int pages;
1195
1196         mtx_assert(&bounce_lock, MA_OWNED);
1197         bz = dmat->bounce_zone;
1198         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1199         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
1200                 return (map->pagesneeded - (map->pagesreserved + pages));
1201         bz->free_bpages -= pages;
1202         bz->reserved_bpages += pages;
1203         map->pagesreserved += pages;
1204         pages = map->pagesneeded - map->pagesreserved;
1205
1206         return (pages);
1207 }
1208
1209 static bus_addr_t
1210 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1211                 bus_addr_t addr, bus_size_t size)
1212 {
1213         struct bounce_zone *bz;
1214         struct bounce_page *bpage;
1215
1216         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
1217         KASSERT((map->flags & DMAMAP_COULD_BOUNCE) != 0,
1218             ("add_bounce_page: bad map %p", map));
1219
1220         bz = dmat->bounce_zone;
1221         if (map->pagesneeded == 0)
1222                 panic("add_bounce_page: map doesn't need any pages");
1223         map->pagesneeded--;
1224
1225         if (map->pagesreserved == 0)
1226                 panic("add_bounce_page: map doesn't need any pages");
1227         map->pagesreserved--;
1228
1229         mtx_lock(&bounce_lock);
1230         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1231         if (bpage == NULL)
1232                 panic("add_bounce_page: free page list is empty");
1233
1234         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1235         bz->reserved_bpages--;
1236         bz->active_bpages++;
1237         mtx_unlock(&bounce_lock);
1238
1239         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1240                 /* Page offset needs to be preserved. */
1241                 bpage->vaddr |= addr & PAGE_MASK;
1242                 bpage->busaddr |= addr & PAGE_MASK;
1243         }
1244         bpage->datavaddr = vaddr;
1245         bpage->datapage = PHYS_TO_VM_PAGE(addr);
1246         bpage->dataoffs = addr & PAGE_MASK;
1247         bpage->datacount = size;
1248         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
1249         return (bpage->busaddr);
1250 }
1251
1252 static void
1253 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1254 {
1255         struct bus_dmamap *map;
1256         struct bounce_zone *bz;
1257         bool schedule_swi;
1258
1259         bz = dmat->bounce_zone;
1260         bpage->datavaddr = 0;
1261         bpage->datacount = 0;
1262         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1263                 /*
1264                  * Reset the bounce page to start at offset 0.  Other uses
1265                  * of this bounce page may need to store a full page of
1266                  * data and/or assume it starts on a page boundary.
1267                  */
1268                 bpage->vaddr &= ~PAGE_MASK;
1269                 bpage->busaddr &= ~PAGE_MASK;
1270         }
1271
1272         schedule_swi = false;
1273         mtx_lock(&bounce_lock);
1274         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1275         bz->free_bpages++;
1276         bz->active_bpages--;
1277         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
1278                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1279                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
1280                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
1281                             map, links);
1282                         bz->total_deferred++;
1283                         schedule_swi = true;
1284                 }
1285         }
1286         mtx_unlock(&bounce_lock);
1287         if (schedule_swi)
1288                 swi_sched(busdma_ih, 0);
1289 }
1290
1291 static void
1292 busdma_swi(void *dummy __unused)
1293 {
1294         bus_dma_tag_t dmat;
1295         struct bus_dmamap *map;
1296
1297         mtx_lock(&bounce_lock);
1298         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1299                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1300                 mtx_unlock(&bounce_lock);
1301                 dmat = map->dmat;
1302                 (dmat->common.lockfunc)(dmat->common.lockfuncarg, BUS_DMA_LOCK);
1303                 bus_dmamap_load_mem(map->dmat, map, &map->mem,
1304                     map->callback, map->callback_arg, BUS_DMA_WAITOK);
1305                 (dmat->common.lockfunc)(dmat->common.lockfuncarg,
1306                     BUS_DMA_UNLOCK);
1307                 mtx_lock(&bounce_lock);
1308         }
1309         mtx_unlock(&bounce_lock);
1310 }
1311
1312 static void
1313 start_busdma_swi(void *dummy __unused)
1314 {
1315         if (swi_add(NULL, "busdma", busdma_swi, NULL, SWI_BUSDMA, INTR_MPSAFE,
1316             &busdma_ih))
1317                 panic("died while creating busdma swi ithread");
1318 }
1319 SYSINIT(start_busdma_swi, SI_SUB_SOFTINTR, SI_ORDER_ANY, start_busdma_swi,
1320     NULL);
1321
1322 struct bus_dma_impl bus_dma_bounce_impl = {
1323         .tag_create = bounce_bus_dma_tag_create,
1324         .tag_destroy = bounce_bus_dma_tag_destroy,
1325         .map_create = bounce_bus_dmamap_create,
1326         .map_destroy = bounce_bus_dmamap_destroy,
1327         .mem_alloc = bounce_bus_dmamem_alloc,
1328         .mem_free = bounce_bus_dmamem_free,
1329         .load_phys = bounce_bus_dmamap_load_phys,
1330         .load_buffer = bounce_bus_dmamap_load_buffer,
1331         .load_ma = bus_dmamap_load_ma_triv,
1332         .map_waitok = bounce_bus_dmamap_waitok,
1333         .map_complete = bounce_bus_dmamap_complete,
1334         .map_unload = bounce_bus_dmamap_unload,
1335         .map_sync = bounce_bus_dmamap_sync
1336 };