sys/x86/x86/busdma_bounce.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 1997, 1998 Justin T. Gibbs.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions, and the following disclaimer,
  12  *    without modification, immediately at the beginning of the file.
  13  * 2. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/domainset.h>
  35 #include <sys/malloc.h>
  36 #include <sys/bus.h>
  37 #include <sys/interrupt.h>
  38 #include <sys/kernel.h>
  39 #include <sys/ktr.h>
  40 #include <sys/lock.h>
  41 #include <sys/proc.h>
  42 #include <sys/memdesc.h>
  43 #include <sys/mutex.h>
  44 #include <sys/sysctl.h>
  45 #include <sys/uio.h>
  46
  47 #include <vm/vm.h>
  48 #include <vm/vm_extern.h>
  49 #include <vm/vm_kern.h>
  50 #include <vm/vm_page.h>
  51 #include <vm/vm_map.h>
  52
  53 #include <machine/atomic.h>
  54 #include <machine/bus.h>
  55 #include <machine/md_var.h>
  56 #include <machine/specialreg.h>
  57 #include <x86/include/busdma_impl.h>
  58
  59 #ifdef __i386__
  60 #define MAX_BPAGES (Maxmem > atop(0x100000000ULL) ? 8192 : 512)
  61 #else
  62 #define MAX_BPAGES 8192
  63 #endif
  64
  65 enum {
  66         BUS_DMA_COULD_BOUNCE    = 0x01,
  67         BUS_DMA_MIN_ALLOC_COMP  = 0x02,
  68         BUS_DMA_KMEM_ALLOC      = 0x04,
  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_offset_t     dataoffs;       /* page offset of client data */
  86         vm_page_t       datapage[2];    /* physical page(s) 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         int             domain;
 104         bus_size_t      alignment;
 105         bus_addr_t      lowaddr;
 106         char            zoneid[8];
 107         char            lowaddrid[20];
 108         struct sysctl_ctx_list sysctl_tree;
 109         struct sysctl_oid *sysctl_tree_top;
 110 };
 111
 112 static struct mtx bounce_lock;
 113 static int total_bpages;
 114 static int busdma_zonecount;
 115 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
 116
 117 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
 118     "Busdma parameters");
 119 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
 120            "Total bounce pages");
 121
 122 struct bus_dmamap {
 123         struct bp_list         bpages;
 124         int                    pagesneeded;
 125         int                    pagesreserved;
 126         bus_dma_tag_t          dmat;
 127         struct memdesc         mem;
 128         bus_dmamap_callback_t *callback;
 129         void                  *callback_arg;
 130         STAILQ_ENTRY(bus_dmamap) links;
 131 };
 132
 133 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 134 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
 135 static struct bus_dmamap nobounce_dmamap;
 136
 137 static void init_bounce_pages(void *dummy);
 138 static int alloc_bounce_zone(bus_dma_tag_t dmat);
 139 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 140 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 141     int commit);
 142 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 143     vm_offset_t vaddr, vm_paddr_t addr1, vm_paddr_t addr2, bus_size_t size);
 144 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 145 static bool _bus_dmamap_pagesneeded(bus_dma_tag_t dmat, vm_paddr_t buf,
 146     bus_size_t buflen, int *pagesneeded);
 147 static void _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 148     pmap_t pmap, void *buf, bus_size_t buflen, int flags);
 149 static void _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 150     vm_paddr_t buf, bus_size_t buflen, int flags);
 151 static int _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 152     int flags);
 153
 154 static int
 155 bounce_bus_dma_zone_setup(bus_dma_tag_t dmat)
 156 {
 157         struct bounce_zone *bz;
 158         int error;
 159
 160         /* Must bounce */
 161         if ((error = alloc_bounce_zone(dmat)) != 0)
 162                 return (error);
 163         bz = dmat->bounce_zone;
 164
 165         if (ptoa(bz->total_bpages) < dmat->common.maxsize) {
 166                 int pages;
 167
 168                 pages = atop(dmat->common.maxsize) - bz->total_bpages;
 169
 170                 /* Add pages to our bounce pool */
 171                 if (alloc_bounce_pages(dmat, pages) < pages)
 172                         return (ENOMEM);
 173         }
 174         /* Performed initial allocation */
 175         dmat->bounce_flags |= BUS_DMA_MIN_ALLOC_COMP;
 176
 177         return (0);
 178 }
 179
 180 /*
 181  * Allocate a device specific dma_tag.
 182  */
 183 static int
 184 bounce_bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 185     bus_addr_t boundary, bus_addr_t lowaddr, bus_addr_t highaddr,
 186     bus_dma_filter_t *filter, void *filterarg, bus_size_t maxsize,
 187     int nsegments, bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
 188     void *lockfuncarg, bus_dma_tag_t *dmat)
 189 {
 190         bus_dma_tag_t newtag;
 191         int error;
 192
 193         *dmat = NULL;
 194         error = common_bus_dma_tag_create(parent != NULL ? &parent->common :
 195             NULL, alignment, boundary, lowaddr, highaddr, filter, filterarg,
 196             maxsize, nsegments, maxsegsz, flags, lockfunc, lockfuncarg,
 197             sizeof (struct bus_dma_tag), (void **)&newtag);
 198         if (error != 0)
 199                 return (error);
 200
 201         newtag->common.impl = &bus_dma_bounce_impl;
 202         newtag->map_count = 0;
 203         newtag->segments = NULL;
 204
 205         if (parent != NULL && (newtag->common.filter != NULL ||
 206             (parent->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0))
 207                 newtag->bounce_flags |= BUS_DMA_COULD_BOUNCE;
 208
 209         if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem) ||
 210             newtag->common.alignment > 1)
 211                 newtag->bounce_flags |= BUS_DMA_COULD_BOUNCE;
 212
 213         if ((newtag->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0 &&
 214             (flags & BUS_DMA_ALLOCNOW) != 0)
 215                 error = bounce_bus_dma_zone_setup(newtag);
 216         else
 217                 error = 0;
 218
 219         if (error != 0)
 220                 free(newtag, M_DEVBUF);
 221         else
 222                 *dmat = newtag;
 223         CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
 224             __func__, newtag, (newtag != NULL ? newtag->common.flags : 0),
 225             error);
 226         return (error);
 227 }
 228
 229 static bool
 230 bounce_bus_dma_id_mapped(bus_dma_tag_t dmat, vm_paddr_t buf, bus_size_t buflen)
 231 {
 232
 233         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) == 0)
 234                 return (true);
 235         return (!_bus_dmamap_pagesneeded(dmat, buf, buflen, NULL));
 236 }
 237
 238 /*
 239  * Update the domain for the tag.  We may need to reallocate the zone and
 240  * bounce pages.
 241  */
 242 static int
 243 bounce_bus_dma_tag_set_domain(bus_dma_tag_t dmat)
 244 {
 245
 246         KASSERT(dmat->map_count == 0,
 247             ("bounce_bus_dma_tag_set_domain:  Domain set after use.\n"));
 248         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) == 0 ||
 249             dmat->bounce_zone == NULL)
 250                 return (0);
 251         dmat->bounce_flags &= ~BUS_DMA_MIN_ALLOC_COMP;
 252         return (bounce_bus_dma_zone_setup(dmat));
 253 }
 254
 255 static int
 256 bounce_bus_dma_tag_destroy(bus_dma_tag_t dmat)
 257 {
 258         bus_dma_tag_t dmat_copy, parent;
 259         int error;
 260
 261         error = 0;
 262         dmat_copy = dmat;
 263
 264         if (dmat != NULL) {
 265                 if (dmat->map_count != 0) {
 266                         error = EBUSY;
 267                         goto out;
 268                 }
 269                 while (dmat != NULL) {
 270                         parent = (bus_dma_tag_t)dmat->common.parent;
 271                         atomic_subtract_int(&dmat->common.ref_count, 1);
 272                         if (dmat->common.ref_count == 0) {
 273                                 if (dmat->segments != NULL)
 274                                         free(dmat->segments, M_DEVBUF);
 275                                 free(dmat, M_DEVBUF);
 276                                 /*
 277                                  * Last reference count, so
 278                                  * release our reference
 279                                  * count on our parent.
 280                                  */
 281                                 dmat = parent;
 282                         } else
 283                                 dmat = NULL;
 284                 }
 285         }
 286 out:
 287         CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
 288         return (error);
 289 }
 290
 291 /*
 292  * Allocate a handle for mapping from kva/uva/physical
 293  * address space into bus device space.
 294  */
 295 static int
 296 bounce_bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 297 {
 298         struct bounce_zone *bz;
 299         int error, maxpages, pages;
 300
 301         error = 0;
 302
 303         if (dmat->segments == NULL) {
 304                 dmat->segments = (bus_dma_segment_t *)malloc_domainset(
 305                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 306                     M_DEVBUF, DOMAINSET_PREF(dmat->common.domain), M_NOWAIT);
 307                 if (dmat->segments == NULL) {
 308                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 309                             __func__, dmat, ENOMEM);
 310                         return (ENOMEM);
 311                 }
 312         }
 313
 314         /*
 315          * Bouncing might be required if the driver asks for an active
 316          * exclusion region, a data alignment that is stricter than 1, and/or
 317          * an active address boundary.
 318          */
 319         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 320                 /* Must bounce */
 321                 if (dmat->bounce_zone == NULL) {
 322                         if ((error = alloc_bounce_zone(dmat)) != 0)
 323                                 return (error);
 324                 }
 325                 bz = dmat->bounce_zone;
 326
 327                 *mapp = (bus_dmamap_t)malloc_domainset(sizeof(**mapp), M_DEVBUF,
 328                     DOMAINSET_PREF(dmat->common.domain), M_NOWAIT | M_ZERO);
 329                 if (*mapp == NULL) {
 330                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 331                             __func__, dmat, ENOMEM);
 332                         return (ENOMEM);
 333                 }
 334
 335                 /* Initialize the new map */
 336                 STAILQ_INIT(&((*mapp)->bpages));
 337
 338                 /*
 339                  * Attempt to add pages to our pool on a per-instance
 340                  * basis up to a sane limit.
 341                  */
 342                 if (dmat->common.alignment > 1)
 343                         maxpages = MAX_BPAGES;
 344                 else
 345                         maxpages = MIN(MAX_BPAGES, Maxmem -
 346                             atop(dmat->common.lowaddr));
 347                 if ((dmat->bounce_flags & BUS_DMA_MIN_ALLOC_COMP) == 0 ||
 348                     (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 349                         pages = MAX(atop(dmat->common.maxsize), 1);
 350                         pages = MIN(maxpages - bz->total_bpages, pages);
 351                         pages = MAX(pages, 1);
 352                         if (alloc_bounce_pages(dmat, pages) < pages)
 353                                 error = ENOMEM;
 354                         if ((dmat->bounce_flags & BUS_DMA_MIN_ALLOC_COMP)
 355                             == 0) {
 356                                 if (error == 0) {
 357                                         dmat->bounce_flags |=
 358                                             BUS_DMA_MIN_ALLOC_COMP;
 359                                 }
 360                         } else
 361                                 error = 0;
 362                 }
 363                 bz->map_count++;
 364         } else {
 365                 *mapp = NULL;
 366         }
 367         if (error == 0)
 368                 dmat->map_count++;
 369         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 370             __func__, dmat, dmat->common.flags, error);
 371         return (error);
 372 }
 373
 374 /*
 375  * Destroy a handle for mapping from kva/uva/physical
 376  * address space into bus device space.
 377  */
 378 static int
 379 bounce_bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 380 {
 381
 382         if (map != NULL && map != &nobounce_dmamap) {
 383                 if (STAILQ_FIRST(&map->bpages) != NULL) {
 384                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 385                             __func__, dmat, EBUSY);
 386                         return (EBUSY);
 387                 }
 388                 if (dmat->bounce_zone)
 389                         dmat->bounce_zone->map_count--;
 390                 free(map, M_DEVBUF);
 391         }
 392         dmat->map_count--;
 393         CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
 394         return (0);
 395 }
 396
 397 /*
 398  * Allocate a piece of memory that can be efficiently mapped into
 399  * bus device space based on the constraints lited in the dma tag.
 400  * A dmamap to for use with dmamap_load is also allocated.
 401  */
 402 static int
 403 bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 404     bus_dmamap_t *mapp)
 405 {
 406         vm_memattr_t attr;
 407         int mflags;
 408
 409         if (flags & BUS_DMA_NOWAIT)
 410                 mflags = M_NOWAIT;
 411         else
 412                 mflags = M_WAITOK;
 413
 414         /* If we succeed, no mapping/bouncing will be required */
 415         *mapp = NULL;
 416
 417         if (dmat->segments == NULL) {
 418                 dmat->segments = (bus_dma_segment_t *)malloc_domainset(
 419                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 420                     M_DEVBUF, DOMAINSET_PREF(dmat->common.domain), mflags);
 421                 if (dmat->segments == NULL) {
 422                         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 423                             __func__, dmat, dmat->common.flags, ENOMEM);
 424                         return (ENOMEM);
 425                 }
 426         }
 427         if (flags & BUS_DMA_ZERO)
 428                 mflags |= M_ZERO;
 429         if (flags & BUS_DMA_NOCACHE)
 430                 attr = VM_MEMATTR_UNCACHEABLE;
 431         else
 432                 attr = VM_MEMATTR_DEFAULT;
 433
 434         /*
 435          * Allocate the buffer from the malloc(9) allocator if...
 436          *  - It's small enough to fit into a single power of two sized bucket.
 437          *  - The alignment is less than or equal to the maximum size
 438          *  - The low address requirement is fulfilled.
 439          * else allocate non-contiguous pages if...
 440          *  - The page count that could get allocated doesn't exceed
 441          *    nsegments also when the maximum segment size is less
 442          *    than PAGE_SIZE.
 443          *  - The alignment constraint isn't larger than a page boundary.
 444          *  - There are no boundary-crossing constraints.
 445          * else allocate a block of contiguous pages because one or more of the
 446          * constraints is something that only the contig allocator can fulfill.
 447          *
 448          * NOTE: The (dmat->common.alignment <= dmat->maxsize) check
 449          * below is just a quick hack. The exact alignment guarantees
 450          * of malloc(9) need to be nailed down, and the code below
 451          * should be rewritten to take that into account.
 452          *
 453          * In the meantime warn the user if malloc gets it wrong.
 454          */
 455         if (dmat->common.maxsize <= PAGE_SIZE &&
 456             dmat->common.alignment <= dmat->common.maxsize &&
 457             dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 458             attr == VM_MEMATTR_DEFAULT) {
 459                 *vaddr = malloc_domainset(dmat->common.maxsize, M_DEVBUF,
 460                     DOMAINSET_PREF(dmat->common.domain), mflags);
 461         } else if (dmat->common.nsegments >=
 462             howmany(dmat->common.maxsize, MIN(dmat->common.maxsegsz,
 463             PAGE_SIZE)) &&
 464             dmat->common.alignment <= PAGE_SIZE &&
 465             (dmat->common.boundary % PAGE_SIZE) == 0) {
 466                 /* Page-based multi-segment allocations allowed */
 467                 *vaddr = (void *)kmem_alloc_attr_domainset(
 468                     DOMAINSET_PREF(dmat->common.domain), dmat->common.maxsize,
 469                     mflags, 0ul, dmat->common.lowaddr, attr);
 470                 dmat->bounce_flags |= BUS_DMA_KMEM_ALLOC;
 471         } else {
 472                 *vaddr = (void *)kmem_alloc_contig_domainset(
 473                     DOMAINSET_PREF(dmat->common.domain), dmat->common.maxsize,
 474                     mflags, 0ul, dmat->common.lowaddr,
 475                     dmat->common.alignment != 0 ? dmat->common.alignment : 1ul,
 476                     dmat->common.boundary, attr);
 477                 dmat->bounce_flags |= BUS_DMA_KMEM_ALLOC;
 478         }
 479         if (*vaddr == NULL) {
 480                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 481                     __func__, dmat, dmat->common.flags, ENOMEM);
 482                 return (ENOMEM);
 483         } else if (vtophys(*vaddr) & (dmat->common.alignment - 1)) {
 484                 printf("bus_dmamem_alloc failed to align memory properly.\n");
 485         }
 486         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 487             __func__, dmat, dmat->common.flags, 0);
 488         return (0);
 489 }
 490
 491 /*
 492  * Free a piece of memory and its associated dmamap, that was allocated
 493  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 494  */
 495 static void
 496 bounce_bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 497 {
 498         /*
 499          * dmamem does not need to be bounced, so the map should be
 500          * NULL and the BUS_DMA_KMEM_ALLOC flag cleared if malloc()
 501          * was used and set if kmem_alloc_contig() was used.
 502          */
 503         if (map != NULL)
 504                 panic("bus_dmamem_free: Invalid map freed\n");
 505         if ((dmat->bounce_flags & BUS_DMA_KMEM_ALLOC) == 0)
 506                 free(vaddr, M_DEVBUF);
 507         else
 508                 kmem_free((vm_offset_t)vaddr, dmat->common.maxsize);
 509         CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat,
 510             dmat->bounce_flags);
 511 }
 512
 513 static bool
 514 _bus_dmamap_pagesneeded(bus_dma_tag_t dmat, vm_paddr_t buf, bus_size_t buflen,
 515     int *pagesneeded)
 516 {
 517         vm_paddr_t curaddr;
 518         bus_size_t sgsize;
 519         int count;
 520
 521         /*
 522          * Count the number of bounce pages needed in order to
 523          * complete this transfer
 524          */
 525         count = 0;
 526         curaddr = buf;
 527         while (buflen != 0) {
 528                 sgsize = MIN(buflen, dmat->common.maxsegsz);
 529                 if (bus_dma_run_filter(&dmat->common, curaddr)) {
 530                         sgsize = MIN(sgsize,
 531                             PAGE_SIZE - (curaddr & PAGE_MASK));
 532                         if (pagesneeded == NULL)
 533                                 return (true);
 534                         count++;
 535                 }
 536                 curaddr += sgsize;
 537                 buflen -= sgsize;
 538         }
 539
 540         if (pagesneeded != NULL)
 541                 *pagesneeded = count;
 542         return (count != 0);
 543 }
 544
 545 static void
 546 _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
 547     bus_size_t buflen, int flags)
 548 {
 549
 550         if (map != &nobounce_dmamap && map->pagesneeded == 0) {
 551                 _bus_dmamap_pagesneeded(dmat, buf, buflen, &map->pagesneeded);
 552                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 553         }
 554 }
 555
 556 static void
 557 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
 558     void *buf, bus_size_t buflen, int flags)
 559 {
 560         vm_offset_t vaddr;
 561         vm_offset_t vendaddr;
 562         vm_paddr_t paddr;
 563         bus_size_t sg_len;
 564
 565         if (map != &nobounce_dmamap && map->pagesneeded == 0) {
 566                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 567                     "alignment= %d", dmat->common.lowaddr,
 568                     ptoa((vm_paddr_t)Maxmem),
 569                     dmat->common.boundary, dmat->common.alignment);
 570                 CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
 571                     map, &nobounce_dmamap, map->pagesneeded);
 572                 /*
 573                  * Count the number of bounce pages
 574                  * needed in order to complete this transfer
 575                  */
 576                 vaddr = (vm_offset_t)buf;
 577                 vendaddr = (vm_offset_t)buf + buflen;
 578
 579                 while (vaddr < vendaddr) {
 580                         sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
 581                         if (pmap == kernel_pmap)
 582                                 paddr = pmap_kextract(vaddr);
 583                         else
 584                                 paddr = pmap_extract(pmap, vaddr);
 585                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 586                                 sg_len = roundup2(sg_len,
 587                                     dmat->common.alignment);
 588                                 map->pagesneeded++;
 589                         }
 590                         vaddr += sg_len;
 591                 }
 592                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 593         }
 594 }
 595
 596 static void
 597 _bus_dmamap_count_ma(bus_dma_tag_t dmat, bus_dmamap_t map, struct vm_page **ma,
 598     int ma_offs, bus_size_t buflen, int flags)
 599 {
 600         bus_size_t sg_len, max_sgsize;
 601         int page_index;
 602         vm_paddr_t paddr;
 603
 604         if (map != &nobounce_dmamap && map->pagesneeded == 0) {
 605                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 606                     "alignment= %d", dmat->common.lowaddr,
 607                     ptoa((vm_paddr_t)Maxmem),
 608                     dmat->common.boundary, dmat->common.alignment);
 609                 CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
 610                     map, &nobounce_dmamap, map->pagesneeded);
 611
 612                 /*
 613                  * Count the number of bounce pages
 614                  * needed in order to complete this transfer
 615                  */
 616                 page_index = 0;
 617                 while (buflen > 0) {
 618                         paddr = VM_PAGE_TO_PHYS(ma[page_index]) + ma_offs;
 619                         sg_len = PAGE_SIZE - ma_offs;
 620                         max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 621                         sg_len = MIN(sg_len, max_sgsize);
 622                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 623                                 sg_len = roundup2(sg_len,
 624                                     dmat->common.alignment);
 625                                 sg_len = MIN(sg_len, max_sgsize);
 626                                 KASSERT((sg_len & (dmat->common.alignment - 1))
 627                                     == 0, ("Segment size is not aligned"));
 628                                 map->pagesneeded++;
 629                         }
 630                         if (((ma_offs + sg_len) & ~PAGE_MASK) != 0)
 631                                 page_index++;
 632                         ma_offs = (ma_offs + sg_len) & PAGE_MASK;
 633                         KASSERT(buflen >= sg_len,
 634                             ("Segment length overruns original buffer"));
 635                         buflen -= sg_len;
 636                 }
 637                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 638         }
 639 }
 640
 641 static int
 642 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
 643 {
 644
 645         /* Reserve Necessary Bounce Pages */
 646         mtx_lock(&bounce_lock);
 647         if (flags & BUS_DMA_NOWAIT) {
 648                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
 649                         mtx_unlock(&bounce_lock);
 650                         return (ENOMEM);
 651                 }
 652         } else {
 653                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
 654                         /* Queue us for resources */
 655                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 656                         mtx_unlock(&bounce_lock);
 657                         return (EINPROGRESS);
 658                 }
 659         }
 660         mtx_unlock(&bounce_lock);
 661
 662         return (0);
 663 }
 664
 665 /*
 666  * Add a single contiguous physical range to the segment list.
 667  */
 668 static bus_size_t
 669 _bus_dmamap_addseg(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t curaddr,
 670     bus_size_t sgsize, bus_dma_segment_t *segs, int *segp)
 671 {
 672         bus_addr_t baddr, bmask;
 673         int seg;
 674
 675         KASSERT(curaddr <= BUS_SPACE_MAXADDR,
 676             ("ds_addr %#jx > BUS_SPACE_MAXADDR %#jx; dmat %p fl %#x low %#jx "
 677             "hi %#jx",
 678             (uintmax_t)curaddr, (uintmax_t)BUS_SPACE_MAXADDR,
 679             dmat, dmat->bounce_flags, (uintmax_t)dmat->common.lowaddr,
 680             (uintmax_t)dmat->common.highaddr));
 681
 682         /*
 683          * Make sure we don't cross any boundaries.
 684          */
 685         bmask = ~(dmat->common.boundary - 1);
 686         if (dmat->common.boundary > 0) {
 687                 baddr = (curaddr + dmat->common.boundary) & bmask;
 688                 if (sgsize > (baddr - curaddr))
 689                         sgsize = (baddr - curaddr);
 690         }
 691
 692         /*
 693          * Insert chunk into a segment, coalescing with
 694          * previous segment if possible.
 695          */
 696         seg = *segp;
 697         if (seg == -1) {
 698                 seg = 0;
 699                 segs[seg].ds_addr = curaddr;
 700                 segs[seg].ds_len = sgsize;
 701         } else {
 702                 if (curaddr == segs[seg].ds_addr + segs[seg].ds_len &&
 703                     (segs[seg].ds_len + sgsize) <= dmat->common.maxsegsz &&
 704                     (dmat->common.boundary == 0 ||
 705                      (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 706                         segs[seg].ds_len += sgsize;
 707                 else {
 708                         if (++seg >= dmat->common.nsegments)
 709                                 return (0);
 710                         segs[seg].ds_addr = curaddr;
 711                         segs[seg].ds_len = sgsize;
 712                 }
 713         }
 714         *segp = seg;
 715         return (sgsize);
 716 }
 717
 718 /*
 719  * Utility function to load a physical buffer.  segp contains
 720  * the starting segment on entrace, and the ending segment on exit.
 721  */
 722 static int
 723 bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 724     vm_paddr_t buf, bus_size_t buflen, int flags, bus_dma_segment_t *segs,
 725     int *segp)
 726 {
 727         bus_size_t sgsize;
 728         vm_paddr_t curaddr;
 729         int error;
 730
 731         if (map == NULL)
 732                 map = &nobounce_dmamap;
 733
 734         if (segs == NULL)
 735                 segs = dmat->segments;
 736
 737         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 738                 _bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
 739                 if (map->pagesneeded != 0) {
 740                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 741                         if (error)
 742                                 return (error);
 743                 }
 744         }
 745
 746         while (buflen > 0) {
 747                 curaddr = buf;
 748                 sgsize = MIN(buflen, dmat->common.maxsegsz);
 749                 if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0 &&
 750                     map->pagesneeded != 0 &&
 751                     bus_dma_run_filter(&dmat->common, curaddr)) {
 752                         sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
 753                         curaddr = add_bounce_page(dmat, map, 0, curaddr, 0,
 754                             sgsize);
 755                 }
 756                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 757                     segp);
 758                 if (sgsize == 0)
 759                         break;
 760                 buf += sgsize;
 761                 buflen -= sgsize;
 762         }
 763
 764         /*
 765          * Did we fit?
 766          */
 767         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 768 }
 769
 770 /*
 771  * Utility function to load a linear buffer.  segp contains
 772  * the starting segment on entrace, and the ending segment on exit.
 773  */
 774 static int
 775 bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 776     bus_size_t buflen, pmap_t pmap, int flags, bus_dma_segment_t *segs,
 777     int *segp)
 778 {
 779         bus_size_t sgsize, max_sgsize;
 780         vm_paddr_t curaddr;
 781         vm_offset_t kvaddr, vaddr;
 782         int error;
 783
 784         if (map == NULL)
 785                 map = &nobounce_dmamap;
 786
 787         if (segs == NULL)
 788                 segs = dmat->segments;
 789
 790         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 791                 _bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
 792                 if (map->pagesneeded != 0) {
 793                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 794                         if (error)
 795                                 return (error);
 796                 }
 797         }
 798
 799         vaddr = (vm_offset_t)buf;
 800         while (buflen > 0) {
 801                 /*
 802                  * Get the physical address for this segment.
 803                  */
 804                 if (pmap == kernel_pmap) {
 805                         curaddr = pmap_kextract(vaddr);
 806                         kvaddr = vaddr;
 807                 } else {
 808                         curaddr = pmap_extract(pmap, vaddr);
 809                         kvaddr = 0;
 810                 }
 811
 812                 /*
 813                  * Compute the segment size, and adjust counts.
 814                  */
 815                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 816                 sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
 817                 if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0 &&
 818                     map->pagesneeded != 0 &&
 819                     bus_dma_run_filter(&dmat->common, curaddr)) {
 820                         sgsize = roundup2(sgsize, dmat->common.alignment);
 821                         sgsize = MIN(sgsize, max_sgsize);
 822                         curaddr = add_bounce_page(dmat, map, kvaddr, curaddr, 0,
 823                             sgsize);
 824                 } else {
 825                         sgsize = MIN(sgsize, max_sgsize);
 826                 }
 827                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 828                     segp);
 829                 if (sgsize == 0)
 830                         break;
 831                 vaddr += sgsize;
 832                 buflen -= sgsize;
 833         }
 834
 835         /*
 836          * Did we fit?
 837          */
 838         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 839 }
 840
 841 static int
 842 bounce_bus_dmamap_load_ma(bus_dma_tag_t dmat, bus_dmamap_t map,
 843     struct vm_page **ma, bus_size_t buflen, int ma_offs, int flags,
 844     bus_dma_segment_t *segs, int *segp)
 845 {
 846         vm_paddr_t paddr, next_paddr;
 847         int error, page_index;
 848         bus_size_t sgsize, max_sgsize;
 849
 850         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
 851                 /*
 852                  * If we have to keep the offset of each page this function
 853                  * is not suitable, switch back to bus_dmamap_load_ma_triv
 854                  * which is going to do the right thing in this case.
 855                  */
 856                 error = bus_dmamap_load_ma_triv(dmat, map, ma, buflen, ma_offs,
 857                     flags, segs, segp);
 858                 return (error);
 859         }
 860
 861         if (map == NULL)
 862                 map = &nobounce_dmamap;
 863
 864         if (segs == NULL)
 865                 segs = dmat->segments;
 866
 867         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 868                 _bus_dmamap_count_ma(dmat, map, ma, ma_offs, buflen, flags);
 869                 if (map->pagesneeded != 0) {
 870                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 871                         if (error)
 872                                 return (error);
 873                 }
 874         }
 875
 876         page_index = 0;
 877         while (buflen > 0) {
 878                 /*
 879                  * Compute the segment size, and adjust counts.
 880                  */
 881                 paddr = VM_PAGE_TO_PHYS(ma[page_index]) + ma_offs;
 882                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 883                 sgsize = PAGE_SIZE - ma_offs;
 884                 if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0 &&
 885                     map->pagesneeded != 0 &&
 886                     bus_dma_run_filter(&dmat->common, paddr)) {
 887                         sgsize = roundup2(sgsize, dmat->common.alignment);
 888                         sgsize = MIN(sgsize, max_sgsize);
 889                         KASSERT((sgsize & (dmat->common.alignment - 1)) == 0,
 890                             ("Segment size is not aligned"));
 891                         /*
 892                          * Check if two pages of the user provided buffer
 893                          * are used.
 894                          */
 895                         if ((ma_offs + sgsize) > PAGE_SIZE)
 896                                 next_paddr =
 897                                     VM_PAGE_TO_PHYS(ma[page_index + 1]);
 898                         else
 899                                 next_paddr = 0;
 900                         paddr = add_bounce_page(dmat, map, 0, paddr,
 901                             next_paddr, sgsize);
 902                 } else {
 903                         sgsize = MIN(sgsize, max_sgsize);
 904                 }
 905                 sgsize = _bus_dmamap_addseg(dmat, map, paddr, sgsize, segs,
 906                     segp);
 907                 if (sgsize == 0)
 908                         break;
 909                 KASSERT(buflen >= sgsize,
 910                     ("Segment length overruns original buffer"));
 911                 buflen -= sgsize;
 912                 if (((ma_offs + sgsize) & ~PAGE_MASK) != 0)
 913                         page_index++;
 914                 ma_offs = (ma_offs + sgsize) & PAGE_MASK;
 915         }
 916
 917         /*
 918          * Did we fit?
 919          */
 920         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 921 }
 922
 923 static void
 924 bounce_bus_dmamap_waitok(bus_dma_tag_t dmat, bus_dmamap_t map,
 925     struct memdesc *mem, bus_dmamap_callback_t *callback, void *callback_arg)
 926 {
 927
 928         if (map == NULL)
 929                 return;
 930         map->mem = *mem;
 931         map->dmat = dmat;
 932         map->callback = callback;
 933         map->callback_arg = callback_arg;
 934 }
 935
 936 static bus_dma_segment_t *
 937 bounce_bus_dmamap_complete(bus_dma_tag_t dmat, bus_dmamap_t map,
 938     bus_dma_segment_t *segs, int nsegs, int error)
 939 {
 940
 941         if (segs == NULL)
 942                 segs = dmat->segments;
 943         return (segs);
 944 }
 945
 946 /*
 947  * Release the mapping held by map.
 948  */
 949 static void
 950 bounce_bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 951 {
 952         struct bounce_page *bpage;
 953
 954         if (map == NULL)
 955                 return;
 956
 957         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 958                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 959                 free_bounce_page(dmat, bpage);
 960         }
 961 }
 962
 963 static void
 964 bounce_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map,
 965     bus_dmasync_op_t op)
 966 {
 967         struct bounce_page *bpage;
 968         vm_offset_t datavaddr, tempvaddr;
 969         bus_size_t datacount1, datacount2;
 970
 971         if (map == NULL || (bpage = STAILQ_FIRST(&map->bpages)) == NULL)
 972                 goto out;
 973
 974         /*
 975          * Handle data bouncing.  We might also want to add support for
 976          * invalidating the caches on broken hardware.
 977          */
 978         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
 979             "performing bounce", __func__, dmat, dmat->common.flags, op);
 980
 981         if ((op & BUS_DMASYNC_PREWRITE) != 0) {
 982                 while (bpage != NULL) {
 983                         tempvaddr = 0;
 984                         datavaddr = bpage->datavaddr;
 985                         datacount1 = bpage->datacount;
 986                         if (datavaddr == 0) {
 987                                 tempvaddr =
 988                                     pmap_quick_enter_page(bpage->datapage[0]);
 989                                 datavaddr = tempvaddr | bpage->dataoffs;
 990                                 datacount1 = min(PAGE_SIZE - bpage->dataoffs,
 991                                     datacount1);
 992                         }
 993
 994                         bcopy((void *)datavaddr,
 995                             (void *)bpage->vaddr, datacount1);
 996
 997                         if (tempvaddr != 0)
 998                                 pmap_quick_remove_page(tempvaddr);
 999
1000                         if (bpage->datapage[1] == 0) {
1001                                 KASSERT(datacount1 == bpage->datacount,
1002                 ("Mismatch between data size and provided memory space"));
1003                                 goto next_w;
1004                         }
1005
1006                         /*
1007                          * We are dealing with an unmapped buffer that expands
1008                          * over two pages.
1009                          */
1010                         datavaddr = pmap_quick_enter_page(bpage->datapage[1]);
1011                         datacount2 = bpage->datacount - datacount1;
1012                         bcopy((void *)datavaddr,
1013                             (void *)(bpage->vaddr + datacount1), datacount2);
1014                         pmap_quick_remove_page(datavaddr);
1015
1016 next_w:
1017                         bpage = STAILQ_NEXT(bpage, links);
1018                 }
1019                 dmat->bounce_zone->total_bounced++;
1020         }
1021
1022         if ((op & BUS_DMASYNC_POSTREAD) != 0) {
1023                 while (bpage != NULL) {
1024                         tempvaddr = 0;
1025                         datavaddr = bpage->datavaddr;
1026                         datacount1 = bpage->datacount;
1027                         if (datavaddr == 0) {
1028                                 tempvaddr =
1029                                     pmap_quick_enter_page(bpage->datapage[0]);
1030                                 datavaddr = tempvaddr | bpage->dataoffs;
1031                                 datacount1 = min(PAGE_SIZE - bpage->dataoffs,
1032                                     datacount1);
1033                         }
1034
1035                         bcopy((void *)bpage->vaddr, (void *)datavaddr,
1036                             datacount1);
1037
1038                         if (tempvaddr != 0)
1039                                 pmap_quick_remove_page(tempvaddr);
1040
1041                         if (bpage->datapage[1] == 0) {
1042                                 KASSERT(datacount1 == bpage->datacount,
1043                 ("Mismatch between data size and provided memory space"));
1044                                 goto next_r;
1045                         }
1046
1047                         /*
1048                          * We are dealing with an unmapped buffer that expands
1049                          * over two pages.
1050                          */
1051                         datavaddr = pmap_quick_enter_page(bpage->datapage[1]);
1052                         datacount2 = bpage->datacount - datacount1;
1053                         bcopy((void *)(bpage->vaddr + datacount1),
1054                             (void *)datavaddr, datacount2);
1055                         pmap_quick_remove_page(datavaddr);
1056
1057 next_r:
1058                         bpage = STAILQ_NEXT(bpage, links);
1059                 }
1060                 dmat->bounce_zone->total_bounced++;
1061         }
1062 out:
1063         atomic_thread_fence_rel();
1064 }
1065
1066 static void
1067 init_bounce_pages(void *dummy __unused)
1068 {
1069
1070         total_bpages = 0;
1071         STAILQ_INIT(&bounce_zone_list);
1072         STAILQ_INIT(&bounce_map_waitinglist);
1073         STAILQ_INIT(&bounce_map_callbacklist);
1074         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
1075 }
1076 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
1077
1078 static struct sysctl_ctx_list *
1079 busdma_sysctl_tree(struct bounce_zone *bz)
1080 {
1081
1082         return (&bz->sysctl_tree);
1083 }
1084
1085 static struct sysctl_oid *
1086 busdma_sysctl_tree_top(struct bounce_zone *bz)
1087 {
1088
1089         return (bz->sysctl_tree_top);
1090 }
1091
1092 static int
1093 alloc_bounce_zone(bus_dma_tag_t dmat)
1094 {
1095         struct bounce_zone *bz;
1096
1097         /* Check to see if we already have a suitable zone */
1098         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1099                 if (dmat->common.alignment <= bz->alignment &&
1100                     dmat->common.lowaddr >= bz->lowaddr &&
1101                     dmat->common.domain == bz->domain) {
1102                         dmat->bounce_zone = bz;
1103                         return (0);
1104                 }
1105         }
1106
1107         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
1108             M_NOWAIT | M_ZERO)) == NULL)
1109                 return (ENOMEM);
1110
1111         STAILQ_INIT(&bz->bounce_page_list);
1112         bz->free_bpages = 0;
1113         bz->reserved_bpages = 0;
1114         bz->active_bpages = 0;
1115         bz->lowaddr = dmat->common.lowaddr;
1116         bz->alignment = MAX(dmat->common.alignment, PAGE_SIZE);
1117         bz->map_count = 0;
1118         bz->domain = dmat->common.domain;
1119         snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1120         busdma_zonecount++;
1121         snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1122         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1123         dmat->bounce_zone = bz;
1124
1125         sysctl_ctx_init(&bz->sysctl_tree);
1126         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
1127             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1128             CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
1129         if (bz->sysctl_tree_top == NULL) {
1130                 sysctl_ctx_free(&bz->sysctl_tree);
1131                 return (0);     /* XXX error code? */
1132         }
1133
1134         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1135             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1136             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1137             "Total bounce pages");
1138         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1139             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1140             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1141             "Free bounce pages");
1142         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1143             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1144             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1145             "Reserved bounce pages");
1146         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1147             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1148             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1149             "Active bounce pages");
1150         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1151             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1152             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1153             "Total bounce requests");
1154         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1155             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1156             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1157             "Total bounce requests that were deferred");
1158         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
1159             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1160             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1161         SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
1162             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1163             "alignment", CTLFLAG_RD, &bz->alignment, "");
1164         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1165             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1166             "domain", CTLFLAG_RD, &bz->domain, 0,
1167             "memory domain");
1168
1169         return (0);
1170 }
1171
1172 static int
1173 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
1174 {
1175         struct bounce_zone *bz;
1176         int count;
1177
1178         bz = dmat->bounce_zone;
1179         count = 0;
1180         while (numpages > 0) {
1181                 struct bounce_page *bpage;
1182
1183                 bpage = malloc_domainset(sizeof(*bpage), M_DEVBUF,
1184                     DOMAINSET_PREF(dmat->common.domain), M_NOWAIT | M_ZERO);
1185
1186                 if (bpage == NULL)
1187                         break;
1188                 bpage->vaddr = (vm_offset_t)contigmalloc_domainset(PAGE_SIZE,
1189                     M_DEVBUF, DOMAINSET_PREF(dmat->common.domain), M_NOWAIT,
1190                     0ul, bz->lowaddr, PAGE_SIZE, 0);
1191                 if (bpage->vaddr == 0) {
1192                         free(bpage, M_DEVBUF);
1193                         break;
1194                 }
1195                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1196                 mtx_lock(&bounce_lock);
1197                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1198                 total_bpages++;
1199                 bz->total_bpages++;
1200                 bz->free_bpages++;
1201                 mtx_unlock(&bounce_lock);
1202                 count++;
1203                 numpages--;
1204         }
1205         return (count);
1206 }
1207
1208 static int
1209 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1210 {
1211         struct bounce_zone *bz;
1212         int pages;
1213
1214         mtx_assert(&bounce_lock, MA_OWNED);
1215         bz = dmat->bounce_zone;
1216         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1217         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
1218                 return (map->pagesneeded - (map->pagesreserved + pages));
1219         bz->free_bpages -= pages;
1220         bz->reserved_bpages += pages;
1221         map->pagesreserved += pages;
1222         pages = map->pagesneeded - map->pagesreserved;
1223
1224         return (pages);
1225 }
1226
1227 static bus_addr_t
1228 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1229     vm_paddr_t addr1, vm_paddr_t addr2, bus_size_t size)
1230 {
1231         struct bounce_zone *bz;
1232         struct bounce_page *bpage;
1233
1234         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
1235         KASSERT(map != NULL && map != &nobounce_dmamap,
1236             ("add_bounce_page: bad map %p", map));
1237
1238         bz = dmat->bounce_zone;
1239         if (map->pagesneeded == 0)
1240                 panic("add_bounce_page: map doesn't need any pages");
1241         map->pagesneeded--;
1242
1243         if (map->pagesreserved == 0)
1244                 panic("add_bounce_page: map doesn't need any pages");
1245         map->pagesreserved--;
1246
1247         mtx_lock(&bounce_lock);
1248         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1249         if (bpage == NULL)
1250                 panic("add_bounce_page: free page list is empty");
1251
1252         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1253         bz->reserved_bpages--;
1254         bz->active_bpages++;
1255         mtx_unlock(&bounce_lock);
1256
1257         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1258                 /* Page offset needs to be preserved. */
1259                 bpage->vaddr |= addr1 & PAGE_MASK;
1260                 bpage->busaddr |= addr1 & PAGE_MASK;
1261                 KASSERT(addr2 == 0,
1262         ("Trying to bounce multiple pages with BUS_DMA_KEEP_PG_OFFSET"));
1263         }
1264         bpage->datavaddr = vaddr;
1265         bpage->datapage[0] = PHYS_TO_VM_PAGE(addr1);
1266         KASSERT((addr2 & PAGE_MASK) == 0, ("Second page is not aligned"));
1267         bpage->datapage[1] = PHYS_TO_VM_PAGE(addr2);
1268         bpage->dataoffs = addr1 & PAGE_MASK;
1269         bpage->datacount = size;
1270         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
1271         return (bpage->busaddr);
1272 }
1273
1274 static void
1275 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1276 {
1277         struct bus_dmamap *map;
1278         struct bounce_zone *bz;
1279
1280         bz = dmat->bounce_zone;
1281         bpage->datavaddr = 0;
1282         bpage->datacount = 0;
1283         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1284                 /*
1285                  * Reset the bounce page to start at offset 0.  Other uses
1286                  * of this bounce page may need to store a full page of
1287                  * data and/or assume it starts on a page boundary.
1288                  */
1289                 bpage->vaddr &= ~PAGE_MASK;
1290                 bpage->busaddr &= ~PAGE_MASK;
1291         }
1292
1293         mtx_lock(&bounce_lock);
1294         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1295         bz->free_bpages++;
1296         bz->active_bpages--;
1297         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
1298                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1299                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
1300                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
1301                             map, links);
1302                         busdma_swi_pending = 1;
1303                         bz->total_deferred++;
1304                         swi_sched(vm_ih, 0);
1305                 }
1306         }
1307         mtx_unlock(&bounce_lock);
1308 }
1309
1310 void
1311 busdma_swi(void)
1312 {
1313         bus_dma_tag_t dmat;
1314         struct bus_dmamap *map;
1315
1316         mtx_lock(&bounce_lock);
1317         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1318                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1319                 mtx_unlock(&bounce_lock);
1320                 dmat = map->dmat;
1321                 (dmat->common.lockfunc)(dmat->common.lockfuncarg, BUS_DMA_LOCK);
1322                 bus_dmamap_load_mem(map->dmat, map, &map->mem,
1323                     map->callback, map->callback_arg, BUS_DMA_WAITOK);
1324                 (dmat->common.lockfunc)(dmat->common.lockfuncarg,
1325                     BUS_DMA_UNLOCK);
1326                 mtx_lock(&bounce_lock);
1327         }
1328         mtx_unlock(&bounce_lock);
1329 }
1330
1331 struct bus_dma_impl bus_dma_bounce_impl = {
1332         .tag_create = bounce_bus_dma_tag_create,
1333         .tag_destroy = bounce_bus_dma_tag_destroy,
1334         .tag_set_domain = bounce_bus_dma_tag_set_domain,
1335         .id_mapped = bounce_bus_dma_id_mapped,
1336         .map_create = bounce_bus_dmamap_create,
1337         .map_destroy = bounce_bus_dmamap_destroy,
1338         .mem_alloc = bounce_bus_dmamem_alloc,
1339         .mem_free = bounce_bus_dmamem_free,
1340         .load_phys = bounce_bus_dmamap_load_phys,
1341         .load_buffer = bounce_bus_dmamap_load_buffer,
1342         .load_ma = bounce_bus_dmamap_load_ma,
1343         .map_waitok = bounce_bus_dmamap_waitok,
1344         .map_complete = bounce_bus_dmamap_complete,
1345         .map_unload = bounce_bus_dmamap_unload,
1346         .map_sync = bounce_bus_dmamap_sync,
1347 };