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/malloc.h>
  35 #include <sys/bus.h>
  36 #include <sys/interrupt.h>
  37 #include <sys/kernel.h>
  38 #include <sys/ktr.h>
  39 #include <sys/lock.h>
  40 #include <sys/proc.h>
  41 #include <sys/memdesc.h>
  42 #include <sys/mutex.h>
  43 #include <sys/sysctl.h>
  44 #include <sys/uio.h>
  45
  46 #include <vm/vm.h>
  47 #include <vm/vm_extern.h>
  48 #include <vm/vm_kern.h>
  49 #include <vm/vm_page.h>
  50 #include <vm/vm_map.h>
  51
  52 #include <machine/atomic.h>
  53 #include <machine/bus.h>
  54 #include <machine/md_var.h>
  55 #include <machine/specialreg.h>
  56 #include <x86/include/busdma_impl.h>
  57
  58 #ifdef __i386__
  59 #define MAX_BPAGES 512
  60 #else
  61 #define MAX_BPAGES 8192
  62 #endif
  63
  64 enum {
  65         BUS_DMA_COULD_BOUNCE    = 0x01,
  66         BUS_DMA_MIN_ALLOC_COMP  = 0x02,
  67         BUS_DMA_KMEM_ALLOC      = 0x04,
  68 };
  69
  70 struct bounce_zone;
  71
  72 struct bus_dma_tag {
  73         struct bus_dma_tag_common common;
  74         int                     map_count;
  75         int                     bounce_flags;
  76         bus_dma_segment_t       *segments;
  77         struct bounce_zone      *bounce_zone;
  78 };
  79
  80 struct bounce_page {
  81         vm_offset_t     vaddr;          /* kva of bounce buffer */
  82         bus_addr_t      busaddr;        /* Physical address */
  83         vm_offset_t     datavaddr;      /* kva of client data */
  84         vm_offset_t     dataoffs;       /* page offset of client data */
  85         vm_page_t       datapage[2];    /* physical page(s) of client data */
  86         bus_size_t      datacount;      /* client data count */
  87         STAILQ_ENTRY(bounce_page) links;
  88 };
  89
  90 int busdma_swi_pending;
  91
  92 struct bounce_zone {
  93         STAILQ_ENTRY(bounce_zone) links;
  94         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  95         int             total_bpages;
  96         int             free_bpages;
  97         int             reserved_bpages;
  98         int             active_bpages;
  99         int             total_bounced;
 100         int             total_deferred;
 101         int             map_count;
 102         bus_size_t      alignment;
 103         bus_addr_t      lowaddr;
 104         char            zoneid[8];
 105         char            lowaddrid[20];
 106         struct sysctl_ctx_list sysctl_tree;
 107         struct sysctl_oid *sysctl_tree_top;
 108 };
 109
 110 static struct mtx bounce_lock;
 111 static int total_bpages;
 112 static int busdma_zonecount;
 113 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
 114
 115 static SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 116 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
 117            "Total bounce pages");
 118
 119 struct bus_dmamap {
 120         struct bp_list         bpages;
 121         int                    pagesneeded;
 122         int                    pagesreserved;
 123         bus_dma_tag_t          dmat;
 124         struct memdesc         mem;
 125         bus_dmamap_callback_t *callback;
 126         void                  *callback_arg;
 127         STAILQ_ENTRY(bus_dmamap) links;
 128 };
 129
 130 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 131 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
 132 static struct bus_dmamap nobounce_dmamap;
 133
 134 static void init_bounce_pages(void *dummy);
 135 static int alloc_bounce_zone(bus_dma_tag_t dmat);
 136 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 137 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 138                                 int commit);
 139 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 140                                   vm_offset_t vaddr, bus_addr_t addr1,
 141                                   bus_addr_t addr2, bus_size_t size);
 142 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 143 int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 144 static void _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 145                                     pmap_t pmap, void *buf, bus_size_t buflen,
 146                                     int flags);
 147 static void _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 148                                    vm_paddr_t buf, bus_size_t buflen,
 149                                    int flags);
 150 static int _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 151                                      int flags);
 152
 153 /*
 154  * Allocate a device specific dma_tag.
 155  */
 156 static int
 157 bounce_bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 158     bus_addr_t boundary, bus_addr_t lowaddr, bus_addr_t highaddr,
 159     bus_dma_filter_t *filter, void *filterarg, bus_size_t maxsize,
 160     int nsegments, bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
 161     void *lockfuncarg, bus_dma_tag_t *dmat)
 162 {
 163         bus_dma_tag_t newtag;
 164         int error;
 165
 166         *dmat = NULL;
 167         error = common_bus_dma_tag_create(parent != NULL ? &parent->common :
 168             NULL, alignment, boundary, lowaddr, highaddr, filter, filterarg,
 169             maxsize, nsegments, maxsegsz, flags, lockfunc, lockfuncarg,
 170             sizeof (struct bus_dma_tag), (void **)&newtag);
 171         if (error != 0)
 172                 return (error);
 173
 174         newtag->common.impl = &bus_dma_bounce_impl;
 175         newtag->map_count = 0;
 176         newtag->segments = NULL;
 177
 178         if (parent != NULL && ((newtag->common.filter != NULL) ||
 179             ((parent->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0)))
 180                 newtag->bounce_flags |= BUS_DMA_COULD_BOUNCE;
 181
 182         if (newtag->common.lowaddr < ptoa((vm_paddr_t)Maxmem) ||
 183             newtag->common.alignment > 1)
 184                 newtag->bounce_flags |= BUS_DMA_COULD_BOUNCE;
 185
 186         if (((newtag->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 187             (flags & BUS_DMA_ALLOCNOW) != 0) {
 188                 struct bounce_zone *bz;
 189
 190                 /* Must bounce */
 191                 if ((error = alloc_bounce_zone(newtag)) != 0) {
 192                         free(newtag, M_DEVBUF);
 193                         return (error);
 194                 }
 195                 bz = newtag->bounce_zone;
 196
 197                 if (ptoa(bz->total_bpages) < maxsize) {
 198                         int pages;
 199
 200                         pages = atop(maxsize) - bz->total_bpages;
 201
 202                         /* Add pages to our bounce pool */
 203                         if (alloc_bounce_pages(newtag, pages) < pages)
 204                                 error = ENOMEM;
 205                 }
 206                 /* Performed initial allocation */
 207                 newtag->bounce_flags |= BUS_DMA_MIN_ALLOC_COMP;
 208         } else
 209                 error = 0;
 210
 211         if (error != 0)
 212                 free(newtag, M_DEVBUF);
 213         else
 214                 *dmat = newtag;
 215         CTR4(KTR_BUSDMA, "%s returned tag %p tag flags 0x%x error %d",
 216             __func__, newtag, (newtag != NULL ? newtag->common.flags : 0),
 217             error);
 218         return (error);
 219 }
 220
 221 static int
 222 bounce_bus_dma_tag_destroy(bus_dma_tag_t dmat)
 223 {
 224         bus_dma_tag_t dmat_copy, parent;
 225         int error;
 226
 227         error = 0;
 228         dmat_copy = dmat;
 229
 230         if (dmat != NULL) {
 231                 if (dmat->map_count != 0) {
 232                         error = EBUSY;
 233                         goto out;
 234                 }
 235                 while (dmat != NULL) {
 236                         parent = (bus_dma_tag_t)dmat->common.parent;
 237                         atomic_subtract_int(&dmat->common.ref_count, 1);
 238                         if (dmat->common.ref_count == 0) {
 239                                 if (dmat->segments != NULL)
 240                                         free(dmat->segments, M_DEVBUF);
 241                                 free(dmat, M_DEVBUF);
 242                                 /*
 243                                  * Last reference count, so
 244                                  * release our reference
 245                                  * count on our parent.
 246                                  */
 247                                 dmat = parent;
 248                         } else
 249                                 dmat = NULL;
 250                 }
 251         }
 252 out:
 253         CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error);
 254         return (error);
 255 }
 256
 257 /*
 258  * Allocate a handle for mapping from kva/uva/physical
 259  * address space into bus device space.
 260  */
 261 static int
 262 bounce_bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 263 {
 264         struct bounce_zone *bz;
 265         int error, maxpages, pages;
 266
 267         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "%s", __func__);
 268
 269         error = 0;
 270
 271         if (dmat->segments == NULL) {
 272                 dmat->segments = (bus_dma_segment_t *)malloc(
 273                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 274                     M_DEVBUF, M_NOWAIT);
 275                 if (dmat->segments == NULL) {
 276                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 277                             __func__, dmat, ENOMEM);
 278                         return (ENOMEM);
 279                 }
 280         }
 281
 282         /*
 283          * Bouncing might be required if the driver asks for an active
 284          * exclusion region, a data alignment that is stricter than 1, and/or
 285          * an active address boundary.
 286          */
 287         if (dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) {
 288                 /* Must bounce */
 289                 if (dmat->bounce_zone == NULL) {
 290                         if ((error = alloc_bounce_zone(dmat)) != 0)
 291                                 return (error);
 292                 }
 293                 bz = dmat->bounce_zone;
 294
 295                 *mapp = (bus_dmamap_t)malloc(sizeof(**mapp), M_DEVBUF,
 296                     M_NOWAIT | M_ZERO);
 297                 if (*mapp == NULL) {
 298                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 299                             __func__, dmat, ENOMEM);
 300                         return (ENOMEM);
 301                 }
 302
 303                 /* Initialize the new map */
 304                 STAILQ_INIT(&((*mapp)->bpages));
 305
 306                 /*
 307                  * Attempt to add pages to our pool on a per-instance
 308                  * basis up to a sane limit.
 309                  */
 310                 if (dmat->common.alignment > 1)
 311                         maxpages = MAX_BPAGES;
 312                 else
 313                         maxpages = MIN(MAX_BPAGES, Maxmem -
 314                             atop(dmat->common.lowaddr));
 315                 if ((dmat->bounce_flags & BUS_DMA_MIN_ALLOC_COMP) == 0 ||
 316                     (bz->map_count > 0 && bz->total_bpages < maxpages)) {
 317                         pages = MAX(atop(dmat->common.maxsize), 1);
 318                         pages = MIN(maxpages - bz->total_bpages, pages);
 319                         pages = MAX(pages, 1);
 320                         if (alloc_bounce_pages(dmat, pages) < pages)
 321                                 error = ENOMEM;
 322                         if ((dmat->bounce_flags & BUS_DMA_MIN_ALLOC_COMP)
 323                             == 0) {
 324                                 if (error == 0) {
 325                                         dmat->bounce_flags |=
 326                                             BUS_DMA_MIN_ALLOC_COMP;
 327                                 }
 328                         } else
 329                                 error = 0;
 330                 }
 331                 bz->map_count++;
 332         } else {
 333                 *mapp = NULL;
 334         }
 335         if (error == 0)
 336                 dmat->map_count++;
 337         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 338             __func__, dmat, dmat->common.flags, error);
 339         return (error);
 340 }
 341
 342 /*
 343  * Destroy a handle for mapping from kva/uva/physical
 344  * address space into bus device space.
 345  */
 346 static int
 347 bounce_bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 348 {
 349
 350         if (map != NULL && map != &nobounce_dmamap) {
 351                 if (STAILQ_FIRST(&map->bpages) != NULL) {
 352                         CTR3(KTR_BUSDMA, "%s: tag %p error %d",
 353                             __func__, dmat, EBUSY);
 354                         return (EBUSY);
 355                 }
 356                 if (dmat->bounce_zone)
 357                         dmat->bounce_zone->map_count--;
 358                 free(map, M_DEVBUF);
 359         }
 360         dmat->map_count--;
 361         CTR2(KTR_BUSDMA, "%s: tag %p error 0", __func__, dmat);
 362         return (0);
 363 }
 364
 365
 366 /*
 367  * Allocate a piece of memory that can be efficiently mapped into
 368  * bus device space based on the constraints lited in the dma tag.
 369  * A dmamap to for use with dmamap_load is also allocated.
 370  */
 371 static int
 372 bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 373     bus_dmamap_t *mapp)
 374 {
 375         vm_memattr_t attr;
 376         int mflags;
 377
 378         WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "%s", __func__);
 379
 380         if (flags & BUS_DMA_NOWAIT)
 381                 mflags = M_NOWAIT;
 382         else
 383                 mflags = M_WAITOK;
 384
 385         /* If we succeed, no mapping/bouncing will be required */
 386         *mapp = NULL;
 387
 388         if (dmat->segments == NULL) {
 389                 dmat->segments = (bus_dma_segment_t *)malloc(
 390                     sizeof(bus_dma_segment_t) * dmat->common.nsegments,
 391                     M_DEVBUF, mflags);
 392                 if (dmat->segments == NULL) {
 393                         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 394                             __func__, dmat, dmat->common.flags, ENOMEM);
 395                         return (ENOMEM);
 396                 }
 397         }
 398         if (flags & BUS_DMA_ZERO)
 399                 mflags |= M_ZERO;
 400         if (flags & BUS_DMA_NOCACHE)
 401                 attr = VM_MEMATTR_UNCACHEABLE;
 402         else
 403                 attr = VM_MEMATTR_DEFAULT;
 404
 405         /*
 406          * Allocate the buffer from the malloc(9) allocator if...
 407          *  - It's small enough to fit into a single power of two sized bucket.
 408          *  - The alignment is less than or equal to the maximum size
 409          *  - The low address requirement is fulfilled.
 410          * else allocate non-contiguous pages if...
 411          *  - The page count that could get allocated doesn't exceed
 412          *    nsegments also when the maximum segment size is less
 413          *    than PAGE_SIZE.
 414          *  - The alignment constraint isn't larger than a page boundary.
 415          *  - There are no boundary-crossing constraints.
 416          * else allocate a block of contiguous pages because one or more of the
 417          * constraints is something that only the contig allocator can fulfill.
 418          *
 419          * NOTE: The (dmat->common.alignment <= dmat->maxsize) check
 420          * below is just a quick hack. The exact alignment guarantees
 421          * of malloc(9) need to be nailed down, and the code below
 422          * should be rewritten to take that into account.
 423          *
 424          * In the meantime warn the user if malloc gets it wrong.
 425          */
 426         if ((dmat->common.maxsize <= PAGE_SIZE) &&
 427            (dmat->common.alignment <= dmat->common.maxsize) &&
 428             dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 429             attr == VM_MEMATTR_DEFAULT) {
 430                 *vaddr = malloc(dmat->common.maxsize, M_DEVBUF, mflags);
 431         } else if (dmat->common.nsegments >=
 432             howmany(dmat->common.maxsize, MIN(dmat->common.maxsegsz, PAGE_SIZE)) &&
 433             dmat->common.alignment <= PAGE_SIZE &&
 434             (dmat->common.boundary % PAGE_SIZE) == 0) {
 435                 /* Page-based multi-segment allocations allowed */
 436                 *vaddr = (void *)kmem_alloc_attr(kernel_arena,
 437                     dmat->common.maxsize, mflags, 0ul, dmat->common.lowaddr,
 438                     attr);
 439                 dmat->bounce_flags |= BUS_DMA_KMEM_ALLOC;
 440         } else {
 441                 *vaddr = (void *)kmem_alloc_contig(kernel_arena,
 442                     dmat->common.maxsize, mflags, 0ul, dmat->common.lowaddr,
 443                     dmat->common.alignment != 0 ? dmat->common.alignment : 1ul,
 444                     dmat->common.boundary, attr);
 445                 dmat->bounce_flags |= BUS_DMA_KMEM_ALLOC;
 446         }
 447         if (*vaddr == NULL) {
 448                 CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 449                     __func__, dmat, dmat->common.flags, ENOMEM);
 450                 return (ENOMEM);
 451         } else if (vtophys(*vaddr) & (dmat->common.alignment - 1)) {
 452                 printf("bus_dmamem_alloc failed to align memory properly.\n");
 453         }
 454         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x error %d",
 455             __func__, dmat, dmat->common.flags, 0);
 456         return (0);
 457 }
 458
 459 /*
 460  * Free a piece of memory and it's allociated dmamap, that was allocated
 461  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 462  */
 463 static void
 464 bounce_bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 465 {
 466         /*
 467          * dmamem does not need to be bounced, so the map should be
 468          * NULL and the BUS_DMA_KMEM_ALLOC flag cleared if malloc()
 469          * was used and set if kmem_alloc_contig() was used.
 470          */
 471         if (map != NULL)
 472                 panic("bus_dmamem_free: Invalid map freed\n");
 473         if ((dmat->bounce_flags & BUS_DMA_KMEM_ALLOC) == 0)
 474                 free(vaddr, M_DEVBUF);
 475         else
 476                 kmem_free(kernel_arena, (vm_offset_t)vaddr,
 477                     dmat->common.maxsize);
 478         CTR3(KTR_BUSDMA, "%s: tag %p flags 0x%x", __func__, dmat,
 479             dmat->bounce_flags);
 480 }
 481
 482 static void
 483 _bus_dmamap_count_phys(bus_dma_tag_t dmat, bus_dmamap_t map, vm_paddr_t buf,
 484     bus_size_t buflen, int flags)
 485 {
 486         bus_addr_t curaddr;
 487         bus_size_t sgsize;
 488
 489         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 490                 /*
 491                  * Count the number of bounce pages
 492                  * needed in order to complete this transfer
 493                  */
 494                 curaddr = buf;
 495                 while (buflen != 0) {
 496                         sgsize = MIN(buflen, dmat->common.maxsegsz);
 497                         if (bus_dma_run_filter(&dmat->common, curaddr)) {
 498                                 sgsize = MIN(sgsize,
 499                                     PAGE_SIZE - (curaddr & PAGE_MASK));
 500                                 map->pagesneeded++;
 501                         }
 502                         curaddr += sgsize;
 503                         buflen -= sgsize;
 504                 }
 505                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 506         }
 507 }
 508
 509 static void
 510 _bus_dmamap_count_pages(bus_dma_tag_t dmat, bus_dmamap_t map, pmap_t pmap,
 511     void *buf, bus_size_t buflen, int flags)
 512 {
 513         vm_offset_t vaddr;
 514         vm_offset_t vendaddr;
 515         bus_addr_t paddr;
 516         bus_size_t sg_len;
 517
 518         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 519                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 520                     "alignment= %d", dmat->common.lowaddr,
 521                     ptoa((vm_paddr_t)Maxmem),
 522                     dmat->common.boundary, dmat->common.alignment);
 523                 CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
 524                     map, &nobounce_dmamap, map->pagesneeded);
 525                 /*
 526                  * Count the number of bounce pages
 527                  * needed in order to complete this transfer
 528                  */
 529                 vaddr = (vm_offset_t)buf;
 530                 vendaddr = (vm_offset_t)buf + buflen;
 531
 532                 while (vaddr < vendaddr) {
 533                         sg_len = PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK);
 534                         if (pmap == kernel_pmap)
 535                                 paddr = pmap_kextract(vaddr);
 536                         else
 537                                 paddr = pmap_extract(pmap, vaddr);
 538                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 539                                 sg_len = roundup2(sg_len,
 540                                     dmat->common.alignment);
 541                                 map->pagesneeded++;
 542                         }
 543                         vaddr += sg_len;
 544                 }
 545                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 546         }
 547 }
 548
 549 static void
 550 _bus_dmamap_count_ma(bus_dma_tag_t dmat, bus_dmamap_t map, struct vm_page **ma,
 551     int ma_offs, bus_size_t buflen, int flags)
 552 {
 553         bus_size_t sg_len, max_sgsize;
 554         int page_index;
 555         vm_paddr_t paddr;
 556
 557         if ((map != &nobounce_dmamap && map->pagesneeded == 0)) {
 558                 CTR4(KTR_BUSDMA, "lowaddr= %d Maxmem= %d, boundary= %d, "
 559                     "alignment= %d", dmat->common.lowaddr,
 560                     ptoa((vm_paddr_t)Maxmem),
 561                     dmat->common.boundary, dmat->common.alignment);
 562                 CTR3(KTR_BUSDMA, "map= %p, nobouncemap= %p, pagesneeded= %d",
 563                     map, &nobounce_dmamap, map->pagesneeded);
 564
 565                 /*
 566                  * Count the number of bounce pages
 567                  * needed in order to complete this transfer
 568                  */
 569                 page_index = 0;
 570                 while (buflen > 0) {
 571                         paddr = VM_PAGE_TO_PHYS(ma[page_index]) + ma_offs;
 572                         sg_len = PAGE_SIZE - ma_offs;
 573                         max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 574                         sg_len = MIN(sg_len, max_sgsize);
 575                         if (bus_dma_run_filter(&dmat->common, paddr) != 0) {
 576                                 sg_len = roundup2(sg_len,
 577                                     dmat->common.alignment);
 578                                 sg_len = MIN(sg_len, max_sgsize);
 579                                 KASSERT((sg_len & (dmat->common.alignment - 1))
 580                                     == 0, ("Segment size is not aligned"));
 581                                 map->pagesneeded++;
 582                         }
 583                         if (((ma_offs + sg_len) & ~PAGE_MASK) != 0)
 584                                 page_index++;
 585                         ma_offs = (ma_offs + sg_len) & PAGE_MASK;
 586                         KASSERT(buflen >= sg_len,
 587                             ("Segment length overruns original buffer"));
 588                         buflen -= sg_len;
 589                 }
 590                 CTR1(KTR_BUSDMA, "pagesneeded= %d\n", map->pagesneeded);
 591         }
 592 }
 593
 594 static int
 595 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
 596 {
 597
 598         /* Reserve Necessary Bounce Pages */
 599         mtx_lock(&bounce_lock);
 600         if (flags & BUS_DMA_NOWAIT) {
 601                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
 602                         mtx_unlock(&bounce_lock);
 603                         return (ENOMEM);
 604                 }
 605         } else {
 606                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
 607                         /* Queue us for resources */
 608                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 609                         mtx_unlock(&bounce_lock);
 610                         return (EINPROGRESS);
 611                 }
 612         }
 613         mtx_unlock(&bounce_lock);
 614
 615         return (0);
 616 }
 617
 618 /*
 619  * Add a single contiguous physical range to the segment list.
 620  */
 621 static int
 622 _bus_dmamap_addseg(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t curaddr,
 623     bus_size_t sgsize, bus_dma_segment_t *segs, int *segp)
 624 {
 625         bus_addr_t baddr, bmask;
 626         int seg;
 627
 628         /*
 629          * Make sure we don't cross any boundaries.
 630          */
 631         bmask = ~(dmat->common.boundary - 1);
 632         if (dmat->common.boundary > 0) {
 633                 baddr = (curaddr + dmat->common.boundary) & bmask;
 634                 if (sgsize > (baddr - curaddr))
 635                         sgsize = (baddr - curaddr);
 636         }
 637
 638         /*
 639          * Insert chunk into a segment, coalescing with
 640          * previous segment if possible.
 641          */
 642         seg = *segp;
 643         if (seg == -1) {
 644                 seg = 0;
 645                 segs[seg].ds_addr = curaddr;
 646                 segs[seg].ds_len = sgsize;
 647         } else {
 648                 if (curaddr == segs[seg].ds_addr + segs[seg].ds_len &&
 649                     (segs[seg].ds_len + sgsize) <= dmat->common.maxsegsz &&
 650                     (dmat->common.boundary == 0 ||
 651                      (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 652                         segs[seg].ds_len += sgsize;
 653                 else {
 654                         if (++seg >= dmat->common.nsegments)
 655                                 return (0);
 656                         segs[seg].ds_addr = curaddr;
 657                         segs[seg].ds_len = sgsize;
 658                 }
 659         }
 660         *segp = seg;
 661         return (sgsize);
 662 }
 663
 664 /*
 665  * Utility function to load a physical buffer.  segp contains
 666  * the starting segment on entrace, and the ending segment on exit.
 667  */
 668 static int
 669 bounce_bus_dmamap_load_phys(bus_dma_tag_t dmat, bus_dmamap_t map,
 670     vm_paddr_t buf, bus_size_t buflen, int flags, bus_dma_segment_t *segs,
 671     int *segp)
 672 {
 673         bus_size_t sgsize;
 674         bus_addr_t curaddr;
 675         int error;
 676
 677         if (map == NULL)
 678                 map = &nobounce_dmamap;
 679
 680         if (segs == NULL)
 681                 segs = dmat->segments;
 682
 683         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 684                 _bus_dmamap_count_phys(dmat, map, buf, buflen, flags);
 685                 if (map->pagesneeded != 0) {
 686                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 687                         if (error)
 688                                 return (error);
 689                 }
 690         }
 691
 692         while (buflen > 0) {
 693                 curaddr = buf;
 694                 sgsize = MIN(buflen, dmat->common.maxsegsz);
 695                 if (((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 696                     map->pagesneeded != 0 &&
 697                     bus_dma_run_filter(&dmat->common, curaddr)) {
 698                         sgsize = MIN(sgsize, PAGE_SIZE - (curaddr & PAGE_MASK));
 699                         curaddr = add_bounce_page(dmat, map, 0, curaddr, 0,
 700                             sgsize);
 701                 }
 702                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 703                     segp);
 704                 if (sgsize == 0)
 705                         break;
 706                 buf += sgsize;
 707                 buflen -= sgsize;
 708         }
 709
 710         /*
 711          * Did we fit?
 712          */
 713         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 714 }
 715
 716 /*
 717  * Utility function to load a linear buffer.  segp contains
 718  * the starting segment on entrace, and the ending segment on exit.
 719  */
 720 static int
 721 bounce_bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 722     bus_size_t buflen, pmap_t pmap, int flags, bus_dma_segment_t *segs,
 723     int *segp)
 724 {
 725         bus_size_t sgsize, max_sgsize;
 726         bus_addr_t curaddr;
 727         vm_offset_t kvaddr, vaddr;
 728         int error;
 729
 730         if (map == NULL)
 731                 map = &nobounce_dmamap;
 732
 733         if (segs == NULL)
 734                 segs = dmat->segments;
 735
 736         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 737                 _bus_dmamap_count_pages(dmat, map, pmap, buf, buflen, flags);
 738                 if (map->pagesneeded != 0) {
 739                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 740                         if (error)
 741                                 return (error);
 742                 }
 743         }
 744
 745         vaddr = (vm_offset_t)buf;
 746         while (buflen > 0) {
 747                 /*
 748                  * Get the physical address for this segment.
 749                  */
 750                 if (pmap == kernel_pmap) {
 751                         curaddr = pmap_kextract(vaddr);
 752                         kvaddr = vaddr;
 753                 } else {
 754                         curaddr = pmap_extract(pmap, vaddr);
 755                         kvaddr = 0;
 756                 }
 757
 758                 /*
 759                  * Compute the segment size, and adjust counts.
 760                  */
 761                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 762                 sgsize = PAGE_SIZE - (curaddr & PAGE_MASK);
 763                 if (((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 764                     map->pagesneeded != 0 &&
 765                     bus_dma_run_filter(&dmat->common, curaddr)) {
 766                         sgsize = roundup2(sgsize, dmat->common.alignment);
 767                         sgsize = MIN(sgsize, max_sgsize);
 768                         curaddr = add_bounce_page(dmat, map, kvaddr, curaddr, 0,
 769                             sgsize);
 770                 } else {
 771                         sgsize = MIN(sgsize, max_sgsize);
 772                 }
 773                 sgsize = _bus_dmamap_addseg(dmat, map, curaddr, sgsize, segs,
 774                     segp);
 775                 if (sgsize == 0)
 776                         break;
 777                 vaddr += sgsize;
 778                 buflen -= sgsize;
 779         }
 780
 781         /*
 782          * Did we fit?
 783          */
 784         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 785 }
 786
 787 static int
 788 bounce_bus_dmamap_load_ma(bus_dma_tag_t dmat, bus_dmamap_t map,
 789     struct vm_page **ma, bus_size_t buflen, int ma_offs, int flags,
 790     bus_dma_segment_t *segs, int *segp)
 791 {
 792         vm_paddr_t paddr, next_paddr;
 793         int error, page_index;
 794         bus_size_t sgsize, max_sgsize;
 795
 796         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
 797                 /*
 798                  * If we have to keep the offset of each page this function
 799                  * is not suitable, switch back to bus_dmamap_load_ma_triv
 800                  * which is going to do the right thing in this case.
 801                  */
 802                 error = bus_dmamap_load_ma_triv(dmat, map, ma, buflen, ma_offs,
 803                     flags, segs, segp);
 804                 return (error);
 805         }
 806
 807         if (map == NULL)
 808                 map = &nobounce_dmamap;
 809
 810         if (segs == NULL)
 811                 segs = dmat->segments;
 812
 813         if ((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) {
 814                 _bus_dmamap_count_ma(dmat, map, ma, ma_offs, buflen, flags);
 815                 if (map->pagesneeded != 0) {
 816                         error = _bus_dmamap_reserve_pages(dmat, map, flags);
 817                         if (error)
 818                                 return (error);
 819                 }
 820         }
 821
 822         page_index = 0;
 823         while (buflen > 0) {
 824                 /*
 825                  * Compute the segment size, and adjust counts.
 826                  */
 827                 paddr = VM_PAGE_TO_PHYS(ma[page_index]) + ma_offs;
 828                 max_sgsize = MIN(buflen, dmat->common.maxsegsz);
 829                 sgsize = PAGE_SIZE - ma_offs;
 830                 if (((dmat->bounce_flags & BUS_DMA_COULD_BOUNCE) != 0) &&
 831                     map->pagesneeded != 0 &&
 832                     bus_dma_run_filter(&dmat->common, paddr)) {
 833                         sgsize = roundup2(sgsize, dmat->common.alignment);
 834                         sgsize = MIN(sgsize, max_sgsize);
 835                         KASSERT((sgsize & (dmat->common.alignment - 1)) == 0,
 836                             ("Segment size is not aligned"));
 837                         /*
 838                          * Check if two pages of the user provided buffer
 839                          * are used.
 840                          */
 841                         if ((ma_offs + sgsize) > PAGE_SIZE)
 842                                 next_paddr =
 843                                     VM_PAGE_TO_PHYS(ma[page_index + 1]);
 844                         else
 845                                 next_paddr = 0;
 846                         paddr = add_bounce_page(dmat, map, 0, paddr,
 847                             next_paddr, sgsize);
 848                 } else {
 849                         sgsize = MIN(sgsize, max_sgsize);
 850                 }
 851                 sgsize = _bus_dmamap_addseg(dmat, map, paddr, sgsize, segs,
 852                     segp);
 853                 if (sgsize == 0)
 854                         break;
 855                 KASSERT(buflen >= sgsize,
 856                     ("Segment length overruns original buffer"));
 857                 buflen -= sgsize;
 858                 if (((ma_offs + sgsize) & ~PAGE_MASK) != 0)
 859                         page_index++;
 860                 ma_offs = (ma_offs + sgsize) & PAGE_MASK;
 861         }
 862
 863         /*
 864          * Did we fit?
 865          */
 866         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 867 }
 868
 869 static void
 870 bounce_bus_dmamap_waitok(bus_dma_tag_t dmat, bus_dmamap_t map,
 871     struct memdesc *mem, bus_dmamap_callback_t *callback, void *callback_arg)
 872 {
 873
 874         if (map == NULL)
 875                 return;
 876         map->mem = *mem;
 877         map->dmat = dmat;
 878         map->callback = callback;
 879         map->callback_arg = callback_arg;
 880 }
 881
 882 static bus_dma_segment_t *
 883 bounce_bus_dmamap_complete(bus_dma_tag_t dmat, bus_dmamap_t map,
 884     bus_dma_segment_t *segs, int nsegs, int error)
 885 {
 886
 887         if (segs == NULL)
 888                 segs = dmat->segments;
 889         return (segs);
 890 }
 891
 892 /*
 893  * Release the mapping held by map.
 894  */
 895 static void
 896 bounce_bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 897 {
 898         struct bounce_page *bpage;
 899
 900         if (map == NULL)
 901                 return;
 902
 903         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 904                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 905                 free_bounce_page(dmat, bpage);
 906         }
 907 }
 908
 909 static void
 910 bounce_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map,
 911     bus_dmasync_op_t op)
 912 {
 913         struct bounce_page *bpage;
 914         vm_offset_t datavaddr, tempvaddr;
 915         bus_size_t datacount1, datacount2;
 916
 917         if (map == NULL || (bpage = STAILQ_FIRST(&map->bpages)) == NULL)
 918                 return;
 919
 920         /*
 921          * Handle data bouncing.  We might also want to add support for
 922          * invalidating the caches on broken hardware.
 923          */
 924         CTR4(KTR_BUSDMA, "%s: tag %p tag flags 0x%x op 0x%x "
 925             "performing bounce", __func__, dmat, dmat->common.flags, op);
 926
 927         if ((op & BUS_DMASYNC_PREWRITE) != 0) {
 928                 while (bpage != NULL) {
 929                         tempvaddr = 0;
 930                         datavaddr = bpage->datavaddr;
 931                         datacount1 = bpage->datacount;
 932                         if (datavaddr == 0) {
 933                                 tempvaddr =
 934                                     pmap_quick_enter_page(bpage->datapage[0]);
 935                                 datavaddr = tempvaddr | bpage->dataoffs;
 936                                 datacount1 = min(PAGE_SIZE - bpage->dataoffs,
 937                                     datacount1);
 938                         }
 939
 940                         bcopy((void *)datavaddr,
 941                             (void *)bpage->vaddr, datacount1);
 942
 943                         if (tempvaddr != 0)
 944                                 pmap_quick_remove_page(tempvaddr);
 945
 946                         if (bpage->datapage[1] == 0) {
 947                                 KASSERT(datacount1 == bpage->datacount,
 948                 ("Mismatch between data size and provided memory space"));
 949                                 goto next_w;
 950                         }
 951
 952                         /*
 953                          * We are dealing with an unmapped buffer that expands
 954                          * over two pages.
 955                          */
 956                         datavaddr = pmap_quick_enter_page(bpage->datapage[1]);
 957                         datacount2 = bpage->datacount - datacount1;
 958                         bcopy((void *)datavaddr,
 959                             (void *)(bpage->vaddr + datacount1), datacount2);
 960                         pmap_quick_remove_page(datavaddr);
 961
 962 next_w:
 963                         bpage = STAILQ_NEXT(bpage, links);
 964                 }
 965                 dmat->bounce_zone->total_bounced++;
 966         }
 967
 968         if ((op & BUS_DMASYNC_POSTREAD) != 0) {
 969                 while (bpage != NULL) {
 970                         tempvaddr = 0;
 971                         datavaddr = bpage->datavaddr;
 972                         datacount1 = bpage->datacount;
 973                         if (datavaddr == 0) {
 974                                 tempvaddr =
 975                                     pmap_quick_enter_page(bpage->datapage[0]);
 976                                 datavaddr = tempvaddr | bpage->dataoffs;
 977                                 datacount1 = min(PAGE_SIZE - bpage->dataoffs,
 978                                     datacount1);
 979                         }
 980
 981                         bcopy((void *)bpage->vaddr, (void *)datavaddr,
 982                             datacount1);
 983
 984                         if (tempvaddr != 0)
 985                                 pmap_quick_remove_page(tempvaddr);
 986
 987                         if (bpage->datapage[1] == 0) {
 988                                 KASSERT(datacount1 == bpage->datacount,
 989                 ("Mismatch between data size and provided memory space"));
 990                                 goto next_r;
 991                         }
 992
 993                         /*
 994                          * We are dealing with an unmapped buffer that expands
 995                          * over two pages.
 996                          */
 997                         datavaddr = pmap_quick_enter_page(bpage->datapage[1]);
 998                         datacount2 = bpage->datacount - datacount1;
 999                         bcopy((void *)(bpage->vaddr + datacount1),
1000                             (void *)datavaddr, datacount2);
1001                         pmap_quick_remove_page(datavaddr);
1002
1003 next_r:
1004                         bpage = STAILQ_NEXT(bpage, links);
1005                 }
1006                 dmat->bounce_zone->total_bounced++;
1007         }
1008 }
1009
1010 static void
1011 init_bounce_pages(void *dummy __unused)
1012 {
1013
1014         total_bpages = 0;
1015         STAILQ_INIT(&bounce_zone_list);
1016         STAILQ_INIT(&bounce_map_waitinglist);
1017         STAILQ_INIT(&bounce_map_callbacklist);
1018         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
1019 }
1020 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
1021
1022 static struct sysctl_ctx_list *
1023 busdma_sysctl_tree(struct bounce_zone *bz)
1024 {
1025
1026         return (&bz->sysctl_tree);
1027 }
1028
1029 static struct sysctl_oid *
1030 busdma_sysctl_tree_top(struct bounce_zone *bz)
1031 {
1032
1033         return (bz->sysctl_tree_top);
1034 }
1035
1036 static int
1037 alloc_bounce_zone(bus_dma_tag_t dmat)
1038 {
1039         struct bounce_zone *bz;
1040
1041         /* Check to see if we already have a suitable zone */
1042         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1043                 if ((dmat->common.alignment <= bz->alignment) &&
1044                     (dmat->common.lowaddr >= bz->lowaddr)) {
1045                         dmat->bounce_zone = bz;
1046                         return (0);
1047                 }
1048         }
1049
1050         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_DEVBUF,
1051             M_NOWAIT | M_ZERO)) == NULL)
1052                 return (ENOMEM);
1053
1054         STAILQ_INIT(&bz->bounce_page_list);
1055         bz->free_bpages = 0;
1056         bz->reserved_bpages = 0;
1057         bz->active_bpages = 0;
1058         bz->lowaddr = dmat->common.lowaddr;
1059         bz->alignment = MAX(dmat->common.alignment, PAGE_SIZE);
1060         bz->map_count = 0;
1061         snprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1062         busdma_zonecount++;
1063         snprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1064         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1065         dmat->bounce_zone = bz;
1066
1067         sysctl_ctx_init(&bz->sysctl_tree);
1068         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
1069             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1070             CTLFLAG_RD, 0, "");
1071         if (bz->sysctl_tree_top == NULL) {
1072                 sysctl_ctx_free(&bz->sysctl_tree);
1073                 return (0);     /* XXX error code? */
1074         }
1075
1076         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1077             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1078             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1079             "Total bounce pages");
1080         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1081             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1082             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1083             "Free bounce pages");
1084         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1085             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1086             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1087             "Reserved bounce pages");
1088         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1089             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1090             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1091             "Active bounce pages");
1092         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1093             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1094             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1095             "Total bounce requests");
1096         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
1097             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1098             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1099             "Total bounce requests that were deferred");
1100         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
1101             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1102             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1103         SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
1104             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
1105             "alignment", CTLFLAG_RD, &bz->alignment, "");
1106
1107         return (0);
1108 }
1109
1110 static int
1111 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
1112 {
1113         struct bounce_zone *bz;
1114         int count;
1115
1116         bz = dmat->bounce_zone;
1117         count = 0;
1118         while (numpages > 0) {
1119                 struct bounce_page *bpage;
1120
1121                 bpage = (struct bounce_page *)malloc(sizeof(*bpage), M_DEVBUF,
1122                                                      M_NOWAIT | M_ZERO);
1123
1124                 if (bpage == NULL)
1125                         break;
1126                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1127                                                          M_NOWAIT, 0ul,
1128                                                          bz->lowaddr,
1129                                                          PAGE_SIZE,
1130                                                          0);
1131                 if (bpage->vaddr == 0) {
1132                         free(bpage, M_DEVBUF);
1133                         break;
1134                 }
1135                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1136                 mtx_lock(&bounce_lock);
1137                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1138                 total_bpages++;
1139                 bz->total_bpages++;
1140                 bz->free_bpages++;
1141                 mtx_unlock(&bounce_lock);
1142                 count++;
1143                 numpages--;
1144         }
1145         return (count);
1146 }
1147
1148 static int
1149 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1150 {
1151         struct bounce_zone *bz;
1152         int pages;
1153
1154         mtx_assert(&bounce_lock, MA_OWNED);
1155         bz = dmat->bounce_zone;
1156         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1157         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
1158                 return (map->pagesneeded - (map->pagesreserved + pages));
1159         bz->free_bpages -= pages;
1160         bz->reserved_bpages += pages;
1161         map->pagesreserved += pages;
1162         pages = map->pagesneeded - map->pagesreserved;
1163
1164         return (pages);
1165 }
1166
1167 static bus_addr_t
1168 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1169                 bus_addr_t addr1, bus_addr_t addr2, bus_size_t size)
1170 {
1171         struct bounce_zone *bz;
1172         struct bounce_page *bpage;
1173
1174         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
1175         KASSERT(map != NULL && map != &nobounce_dmamap,
1176             ("add_bounce_page: bad map %p", map));
1177
1178         bz = dmat->bounce_zone;
1179         if (map->pagesneeded == 0)
1180                 panic("add_bounce_page: map doesn't need any pages");
1181         map->pagesneeded--;
1182
1183         if (map->pagesreserved == 0)
1184                 panic("add_bounce_page: map doesn't need any pages");
1185         map->pagesreserved--;
1186
1187         mtx_lock(&bounce_lock);
1188         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1189         if (bpage == NULL)
1190                 panic("add_bounce_page: free page list is empty");
1191
1192         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1193         bz->reserved_bpages--;
1194         bz->active_bpages++;
1195         mtx_unlock(&bounce_lock);
1196
1197         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1198                 /* Page offset needs to be preserved. */
1199                 bpage->vaddr |= addr1 & PAGE_MASK;
1200                 bpage->busaddr |= addr1 & PAGE_MASK;
1201                 KASSERT(addr2 == 0,
1202         ("Trying to bounce multiple pages with BUS_DMA_KEEP_PG_OFFSET"));
1203         }
1204         bpage->datavaddr = vaddr;
1205         bpage->datapage[0] = PHYS_TO_VM_PAGE(addr1);
1206         KASSERT((addr2 & PAGE_MASK) == 0, ("Second page is not aligned"));
1207         bpage->datapage[1] = PHYS_TO_VM_PAGE(addr2);
1208         bpage->dataoffs = addr1 & PAGE_MASK;
1209         bpage->datacount = size;
1210         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
1211         return (bpage->busaddr);
1212 }
1213
1214 static void
1215 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1216 {
1217         struct bus_dmamap *map;
1218         struct bounce_zone *bz;
1219
1220         bz = dmat->bounce_zone;
1221         bpage->datavaddr = 0;
1222         bpage->datacount = 0;
1223         if (dmat->common.flags & BUS_DMA_KEEP_PG_OFFSET) {
1224                 /*
1225                  * Reset the bounce page to start at offset 0.  Other uses
1226                  * of this bounce page may need to store a full page of
1227                  * data and/or assume it starts on a page boundary.
1228                  */
1229                 bpage->vaddr &= ~PAGE_MASK;
1230                 bpage->busaddr &= ~PAGE_MASK;
1231         }
1232
1233         mtx_lock(&bounce_lock);
1234         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1235         bz->free_bpages++;
1236         bz->active_bpages--;
1237         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
1238                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1239                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
1240                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
1241                             map, links);
1242                         busdma_swi_pending = 1;
1243                         bz->total_deferred++;
1244                         swi_sched(vm_ih, 0);
1245                 }
1246         }
1247         mtx_unlock(&bounce_lock);
1248 }
1249
1250 void
1251 busdma_swi(void)
1252 {
1253         bus_dma_tag_t dmat;
1254         struct bus_dmamap *map;
1255
1256         mtx_lock(&bounce_lock);
1257         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1258                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1259                 mtx_unlock(&bounce_lock);
1260                 dmat = map->dmat;
1261                 (dmat->common.lockfunc)(dmat->common.lockfuncarg, BUS_DMA_LOCK);
1262                 bus_dmamap_load_mem(map->dmat, map, &map->mem,
1263                     map->callback, map->callback_arg, BUS_DMA_WAITOK);
1264                 (dmat->common.lockfunc)(dmat->common.lockfuncarg,
1265                     BUS_DMA_UNLOCK);
1266                 mtx_lock(&bounce_lock);
1267         }
1268         mtx_unlock(&bounce_lock);
1269 }
1270
1271 struct bus_dma_impl bus_dma_bounce_impl = {
1272         .tag_create = bounce_bus_dma_tag_create,
1273         .tag_destroy = bounce_bus_dma_tag_destroy,
1274         .map_create = bounce_bus_dmamap_create,
1275         .map_destroy = bounce_bus_dmamap_destroy,
1276         .mem_alloc = bounce_bus_dmamem_alloc,
1277         .mem_free = bounce_bus_dmamem_free,
1278         .load_phys = bounce_bus_dmamap_load_phys,
1279         .load_buffer = bounce_bus_dmamap_load_buffer,
1280         .load_ma = bounce_bus_dmamap_load_ma,
1281         .map_waitok = bounce_bus_dmamap_waitok,
1282         .map_complete = bounce_bus_dmamap_complete,
1283         .map_unload = bounce_bus_dmamap_unload,
1284         .map_sync = bounce_bus_dmamap_sync
1285 };