sys/platform/pc64/x86_64/busdma_machdep.c

   1 /*
   2  * Copyright (c) 1997, 1998 Justin T. Gibbs.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions, and the following disclaimer,
  10  *    without modification, immediately at the beginning of the file.
  11  * 2. The name of the author may not be used to endorse or promote products
  12  *    derived from this software without specific prior written permission.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  18  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/i386/i386/busdma_machdep.c,v 1.94 2008/08/15 20:51:31 kmacy Exp $
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/systm.h>
  31 #include <sys/malloc.h>
  32 #include <sys/mbuf.h>
  33 #include <sys/uio.h>
  34 #include <sys/bus_dma.h>
  35 #include <sys/kernel.h>
  36 #include <sys/sysctl.h>
  37 #include <sys/lock.h>
  38
  39 #include <sys/thread2.h>
  40 #include <sys/spinlock2.h>
  41 #include <sys/mplock2.h>
  42
  43 #include <vm/vm.h>
  44 #include <vm/vm_page.h>
  45
  46 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  47 #include <sys/proc.h>
  48 #include <sys/lock.h>
  49 #include <vm/vm_map.h>
  50
  51 #include <machine/md_var.h>
  52
  53 #define MAX_BPAGES      1024
  54
  55 /*
  56  * 16 x N declared on stack.
  57  */
  58 #define BUS_DMA_CACHE_SEGMENTS  8
  59
  60 struct bounce_zone;
  61 struct bus_dmamap;
  62
  63 struct bus_dma_tag {
  64         bus_dma_tag_t   parent;
  65         bus_size_t      alignment;
  66         bus_size_t      boundary;
  67         bus_addr_t      lowaddr;
  68         bus_addr_t      highaddr;
  69         bus_dma_filter_t *filter;
  70         void            *filterarg;
  71         bus_size_t      maxsize;
  72         u_int           nsegments;
  73         bus_size_t      maxsegsz;
  74         int             flags;
  75         int             ref_count;
  76         int             map_count;
  77         bus_dma_segment_t *segments;
  78         struct bounce_zone *bounce_zone;
  79         struct spinlock spin;
  80 };
  81
  82 /*
  83  * bus_dma_tag private flags
  84  */
  85 #define BUS_DMA_BOUNCE_ALIGN    BUS_DMA_BUS2
  86 #define BUS_DMA_BOUNCE_LOWADDR  BUS_DMA_BUS3
  87 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  88
  89 #define BUS_DMA_COULD_BOUNCE    (BUS_DMA_BOUNCE_LOWADDR | BUS_DMA_BOUNCE_ALIGN)
  90
  91 #define BUS_DMAMEM_KMALLOC(dmat) \
  92         ((dmat)->maxsize <= PAGE_SIZE && \
  93          (dmat)->alignment <= PAGE_SIZE && \
  94          (dmat)->lowaddr >= ptoa(Maxmem))
  95
  96 struct bounce_page {
  97         vm_offset_t     vaddr;          /* kva of bounce buffer */
  98         bus_addr_t      busaddr;        /* Physical address */
  99         vm_offset_t     datavaddr;      /* kva of client data */
 100         bus_size_t      datacount;      /* client data count */
 101         STAILQ_ENTRY(bounce_page) links;
 102 };
 103
 104 struct bounce_zone {
 105         STAILQ_ENTRY(bounce_zone) links;
 106         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
 107         STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 108         struct spinlock spin;
 109         int             total_bpages;
 110         int             free_bpages;
 111         int             reserved_bpages;
 112         int             active_bpages;
 113         int             total_bounced;
 114         int             total_deferred;
 115         int             reserve_failed;
 116         bus_size_t      alignment;
 117         bus_addr_t      lowaddr;
 118         char            zoneid[8];
 119         char            lowaddrid[20];
 120         struct sysctl_ctx_list sysctl_ctx;
 121         struct sysctl_oid *sysctl_tree;
 122 };
 123
 124 #define BZ_LOCK(bz)     spin_lock(&(bz)->spin)
 125 #define BZ_UNLOCK(bz)   spin_unlock(&(bz)->spin)
 126
 127 static struct lwkt_token bounce_zone_tok =
 128         LWKT_TOKEN_INITIALIZER(bounce_zone_token);
 129 static int busdma_zonecount;
 130 static STAILQ_HEAD(, bounce_zone) bounce_zone_list =
 131         STAILQ_HEAD_INITIALIZER(bounce_zone_list);
 132
 133 static int busdma_priv_zonecount = -1;
 134
 135 int busdma_swi_pending;
 136 static int total_bounce_pages;
 137 static int max_bounce_pages = MAX_BPAGES;
 138 static int bounce_alignment = 1; /* XXX temporary */
 139
 140 TUNABLE_INT("hw.busdma.max_bpages", &max_bounce_pages);
 141 TUNABLE_INT("hw.busdma.bounce_alignment", &bounce_alignment);
 142
 143 struct bus_dmamap {
 144         struct bp_list  bpages;
 145         int             pagesneeded;
 146         int             pagesreserved;
 147         bus_dma_tag_t   dmat;
 148         void            *buf;           /* unmapped buffer pointer */
 149         bus_size_t      buflen;         /* unmapped buffer length */
 150         bus_dmamap_callback_t *callback;
 151         void            *callback_arg;
 152         STAILQ_ENTRY(bus_dmamap) links;
 153 };
 154
 155 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist =
 156         STAILQ_HEAD_INITIALIZER(bounce_map_callbacklist);
 157 static struct spinlock bounce_map_list_spin =
 158         SPINLOCK_INITIALIZER(&bounce_map_list_spin);
 159
 160 static struct bus_dmamap nobounce_dmamap;
 161
 162 static int              alloc_bounce_zone(bus_dma_tag_t);
 163 static int              alloc_bounce_pages(bus_dma_tag_t, u_int, int);
 164 static void             free_bounce_pages_all(bus_dma_tag_t);
 165 static void             free_bounce_zone(bus_dma_tag_t);
 166 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
 167 static void             return_bounce_pages(bus_dma_tag_t, bus_dmamap_t);
 168 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
 169                             vm_offset_t, bus_size_t);
 170 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
 171
 172 static bus_dmamap_t     get_map_waiting(bus_dma_tag_t);
 173 static void             add_map_callback(bus_dmamap_t);
 174
 175 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 176 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bounce_pages,
 177            0, "Total bounce pages");
 178 SYSCTL_INT(_hw_busdma, OID_AUTO, max_bpages, CTLFLAG_RD, &max_bounce_pages,
 179            0, "Max bounce pages per bounce zone");
 180 SYSCTL_INT(_hw_busdma, OID_AUTO, bounce_alignment, CTLFLAG_RD,
 181            &bounce_alignment, 0, "Obey alignment constraint");
 182
 183 static __inline int
 184 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 185 {
 186         int retval;
 187
 188         retval = 0;
 189         do {
 190                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr) ||
 191                      (bounce_alignment && (paddr & (dmat->alignment - 1)) != 0))
 192                  && (dmat->filter == NULL ||
 193                      dmat->filter(dmat->filterarg, paddr) != 0))
 194                         retval = 1;
 195
 196                 dmat = dmat->parent;
 197         } while (retval == 0 && dmat != NULL);
 198         return (retval);
 199 }
 200
 201 static __inline
 202 bus_dma_segment_t *
 203 bus_dma_tag_lock(bus_dma_tag_t tag, bus_dma_segment_t *cache)
 204 {
 205         if (tag->flags & BUS_DMA_PROTECTED)
 206                 return(tag->segments);
 207
 208         if (tag->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 209                 return(cache);
 210         spin_lock(&tag->spin);
 211         return(tag->segments);
 212 }
 213
 214 static __inline
 215 void
 216 bus_dma_tag_unlock(bus_dma_tag_t tag)
 217 {
 218         if (tag->flags & BUS_DMA_PROTECTED)
 219                 return;
 220
 221         if (tag->nsegments > BUS_DMA_CACHE_SEGMENTS)
 222                 spin_unlock(&tag->spin);
 223 }
 224
 225 /*
 226  * Allocate a device specific dma_tag.
 227  */
 228 int
 229 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 230                    bus_size_t boundary, bus_addr_t lowaddr,
 231                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 232                    void *filterarg, bus_size_t maxsize, int nsegments,
 233                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 234 {
 235         bus_dma_tag_t newtag;
 236         int error = 0;
 237
 238         /*
 239          * Sanity checks
 240          */
 241
 242         if (alignment == 0)
 243                 alignment = 1;
 244         if (alignment & (alignment - 1))
 245                 panic("alignment must be power of 2");
 246
 247         if (boundary != 0) {
 248                 if (boundary & (boundary - 1))
 249                         panic("boundary must be power of 2");
 250                 if (boundary < maxsegsz) {
 251                         kprintf("boundary < maxsegsz:\n");
 252                         print_backtrace(-1);
 253                         maxsegsz = boundary;
 254                 }
 255         }
 256
 257         /* Return a NULL tag on failure */
 258         *dmat = NULL;
 259
 260         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT | M_ZERO);
 261
 262         spin_init(&newtag->spin);
 263         newtag->parent = parent;
 264         newtag->alignment = alignment;
 265         newtag->boundary = boundary;
 266         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 267         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 268         newtag->filter = filter;
 269         newtag->filterarg = filterarg;
 270         newtag->maxsize = maxsize;
 271         newtag->nsegments = nsegments;
 272         newtag->maxsegsz = maxsegsz;
 273         newtag->flags = flags;
 274         newtag->ref_count = 1; /* Count ourself */
 275         newtag->map_count = 0;
 276         newtag->segments = NULL;
 277         newtag->bounce_zone = NULL;
 278
 279         /* Take into account any restrictions imposed by our parent tag */
 280         if (parent != NULL) {
 281                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 282                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 283
 284                 if (newtag->boundary == 0) {
 285                         newtag->boundary = parent->boundary;
 286                 } else if (parent->boundary != 0) {
 287                         newtag->boundary = MIN(parent->boundary,
 288                                                newtag->boundary);
 289                 }
 290
 291 #ifdef notyet
 292                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
 293 #endif
 294
 295                 if (newtag->filter == NULL) {
 296                         /*
 297                          * Short circuit looking at our parent directly
 298                          * since we have encapsulated all of its information
 299                          */
 300                         newtag->filter = parent->filter;
 301                         newtag->filterarg = parent->filterarg;
 302                         newtag->parent = parent->parent;
 303                 }
 304                 if (newtag->parent != NULL)
 305                         parent->ref_count++;
 306         }
 307
 308         if (newtag->lowaddr < ptoa(Maxmem))
 309                 newtag->flags |= BUS_DMA_BOUNCE_LOWADDR;
 310         if (bounce_alignment && newtag->alignment > 1 &&
 311             !(newtag->flags & BUS_DMA_ALIGNED))
 312                 newtag->flags |= BUS_DMA_BOUNCE_ALIGN;
 313
 314         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
 315             (flags & BUS_DMA_ALLOCNOW) != 0) {
 316                 struct bounce_zone *bz;
 317
 318                 /* Must bounce */
 319
 320                 error = alloc_bounce_zone(newtag);
 321                 if (error)
 322                         goto back;
 323                 bz = newtag->bounce_zone;
 324
 325                 if ((newtag->flags & BUS_DMA_ALLOCALL) == 0 &&
 326                     ptoa(bz->total_bpages) < maxsize) {
 327                         int pages;
 328
 329                         if (flags & BUS_DMA_ONEBPAGE) {
 330                                 pages = 1;
 331                         } else {
 332                                 pages = atop(round_page(maxsize)) -
 333                                         bz->total_bpages;
 334                                 pages = MAX(pages, 1);
 335                         }
 336
 337                         /* Add pages to our bounce pool */
 338                         if (alloc_bounce_pages(newtag, pages, flags) < pages)
 339                                 error = ENOMEM;
 340
 341                         /* Performed initial allocation */
 342                         newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 343                 }
 344         }
 345 back:
 346         if (error) {
 347                 free_bounce_zone(newtag);
 348                 kfree(newtag, M_DEVBUF);
 349         } else {
 350                 *dmat = newtag;
 351         }
 352         return error;
 353 }
 354
 355 int
 356 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 357 {
 358         if (dmat != NULL) {
 359                 if (dmat->map_count != 0)
 360                         return (EBUSY);
 361
 362                 while (dmat != NULL) {
 363                         bus_dma_tag_t parent;
 364
 365                         parent = dmat->parent;
 366                         dmat->ref_count--;
 367                         if (dmat->ref_count == 0) {
 368                                 free_bounce_zone(dmat);
 369                                 if (dmat->segments != NULL)
 370                                         kfree(dmat->segments, M_DEVBUF);
 371                                 kfree(dmat, M_DEVBUF);
 372                                 /*
 373                                  * Last reference count, so
 374                                  * release our reference
 375                                  * count on our parent.
 376                                  */
 377                                 dmat = parent;
 378                         } else
 379                                 dmat = NULL;
 380                 }
 381         }
 382         return (0);
 383 }
 384
 385 bus_size_t
 386 bus_dma_tag_getmaxsize(bus_dma_tag_t tag)
 387 {
 388         return(tag->maxsize);
 389 }
 390
 391 /*
 392  * Allocate a handle for mapping from kva/uva/physical
 393  * address space into bus device space.
 394  */
 395 int
 396 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 397 {
 398         int error;
 399
 400         error = 0;
 401
 402         if (dmat->segments == NULL) {
 403                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 404                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 405                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 406         }
 407
 408         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 409                 struct bounce_zone *bz;
 410                 int maxpages;
 411
 412                 /* Must bounce */
 413
 414                 if (dmat->bounce_zone == NULL) {
 415                         error = alloc_bounce_zone(dmat);
 416                         if (error)
 417                                 return error;
 418                 }
 419                 bz = dmat->bounce_zone;
 420
 421                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
 422
 423                 /* Initialize the new map */
 424                 STAILQ_INIT(&((*mapp)->bpages));
 425
 426                 /*
 427                  * Attempt to add pages to our pool on a per-instance
 428                  * basis up to a sane limit.
 429                  */
 430                 if (dmat->flags & BUS_DMA_ALLOCALL) {
 431                         maxpages = Maxmem - atop(dmat->lowaddr);
 432                 } else if (dmat->flags & BUS_DMA_BOUNCE_ALIGN) {
 433                         maxpages = max_bounce_pages;
 434                 } else {
 435                         maxpages = MIN(max_bounce_pages,
 436                                        Maxmem - atop(dmat->lowaddr));
 437                 }
 438                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0 ||
 439                     (dmat->map_count > 0 && bz->total_bpages < maxpages)) {
 440                         int pages;
 441
 442                         if (flags & BUS_DMA_ONEBPAGE) {
 443                                 pages = 1;
 444                         } else {
 445                                 pages = atop(round_page(dmat->maxsize));
 446                                 pages = MIN(maxpages - bz->total_bpages, pages);
 447                                 pages = MAX(pages, 1);
 448                         }
 449                         if (alloc_bounce_pages(dmat, pages, flags) < pages)
 450                                 error = ENOMEM;
 451
 452                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 453                                 if (!error &&
 454                                     (dmat->flags & BUS_DMA_ALLOCALL) == 0)
 455                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 456                         } else {
 457                                 error = 0;
 458                         }
 459                 }
 460         } else {
 461                 *mapp = NULL;
 462         }
 463         if (!error) {
 464                 dmat->map_count++;
 465         } else {
 466                 kfree(*mapp, M_DEVBUF);
 467                 *mapp = NULL;
 468         }
 469         return error;
 470 }
 471
 472 /*
 473  * Destroy a handle for mapping from kva/uva/physical
 474  * address space into bus device space.
 475  */
 476 int
 477 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 478 {
 479         if (map != NULL) {
 480                 if (STAILQ_FIRST(&map->bpages) != NULL)
 481                         return (EBUSY);
 482                 kfree(map, M_DEVBUF);
 483         }
 484         dmat->map_count--;
 485         return (0);
 486 }
 487
 488 static __inline bus_size_t
 489 check_kmalloc(bus_dma_tag_t dmat, const void *vaddr0, int verify)
 490 {
 491         bus_size_t maxsize = 0;
 492         uintptr_t vaddr = (uintptr_t)vaddr0;
 493
 494         if ((vaddr ^ (vaddr + dmat->maxsize - 1)) & ~PAGE_MASK) {
 495                 if (verify)
 496                         panic("boundary check failed\n");
 497                 if (bootverbose)
 498                         kprintf("boundary check failed\n");
 499                 maxsize = dmat->maxsize;
 500         }
 501         if (vaddr & (dmat->alignment - 1)) {
 502                 if (verify)
 503                         panic("alignment check failed\n");
 504                 if (bootverbose)
 505                         kprintf("alignment check failed\n");
 506                 if (dmat->maxsize < dmat->alignment)
 507                         maxsize = dmat->alignment;
 508                 else
 509                         maxsize = dmat->maxsize;
 510         }
 511         return maxsize;
 512 }
 513
 514 /*
 515  * Allocate a piece of memory that can be efficiently mapped into
 516  * bus device space based on the constraints lited in the dma tag.
 517  *
 518  * mapp is degenerate.  By definition this allocation should not require
 519  * bounce buffers so do not allocate a dma map.
 520  */
 521 int
 522 bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr, int flags,
 523                  bus_dmamap_t *mapp)
 524 {
 525         int mflags;
 526
 527         /* If we succeed, no mapping/bouncing will be required */
 528         *mapp = NULL;
 529
 530         if (dmat->segments == NULL) {
 531                 KKASSERT(dmat->nsegments < 16384);
 532                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 533                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 534         }
 535
 536         if (flags & BUS_DMA_NOWAIT)
 537                 mflags = M_NOWAIT;
 538         else
 539                 mflags = M_WAITOK;
 540         if (flags & BUS_DMA_ZERO)
 541                 mflags |= M_ZERO;
 542
 543         if (BUS_DMAMEM_KMALLOC(dmat)) {
 544                 bus_size_t maxsize;
 545
 546                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 547
 548                 /*
 549                  * XXX
 550                  * Check whether the allocation
 551                  * - crossed a page boundary
 552                  * - was not aligned
 553                  * Retry with power-of-2 alignment in the above cases.
 554                  */
 555                 maxsize = check_kmalloc(dmat, *vaddr, 0);
 556                 if (maxsize) {
 557                         kfree(*vaddr, M_DEVBUF);
 558                         *vaddr = kmalloc(maxsize, M_DEVBUF,
 559                             mflags | M_POWEROF2);
 560                         check_kmalloc(dmat, *vaddr, 1);
 561                 }
 562         } else {
 563                 /*
 564                  * XXX Use Contigmalloc until it is merged into this facility
 565                  *     and handles multi-seg allocations.  Nobody is doing
 566                  *     multi-seg allocations yet though.
 567                  */
 568                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 569                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
 570         }
 571         if (*vaddr == NULL)
 572                 return (ENOMEM);
 573         return (0);
 574 }
 575
 576 /*
 577  * Free a piece of memory and it's allociated dmamap, that was allocated
 578  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 579  */
 580 void
 581 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 582 {
 583         /*
 584          * dmamem does not need to be bounced, so the map should be
 585          * NULL
 586          */
 587         if (map != NULL)
 588                 panic("bus_dmamem_free: Invalid map freed");
 589         if (BUS_DMAMEM_KMALLOC(dmat))
 590                 kfree(vaddr, M_DEVBUF);
 591         else
 592                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 593 }
 594
 595 static __inline vm_paddr_t
 596 _bus_dma_extract(pmap_t pmap, vm_offset_t vaddr)
 597 {
 598         if (pmap)
 599                 return pmap_extract(pmap, vaddr);
 600         else
 601                 return pmap_kextract(vaddr);
 602 }
 603
 604 /*
 605  * Utility function to load a linear buffer.  lastaddrp holds state
 606  * between invocations (for multiple-buffer loads).  segp contains
 607  * the segment following the starting one on entrace, and the ending
 608  * segment on exit.  first indicates if this is the first invocation
 609  * of this function.
 610  */
 611 static int
 612 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 613                         bus_dmamap_t map,
 614                         void *buf, bus_size_t buflen,
 615                         bus_dma_segment_t *segments,
 616                         int nsegments,
 617                         pmap_t pmap,
 618                         int flags,
 619                         vm_paddr_t *lastpaddrp,
 620                         int *segp,
 621                         int first)
 622 {
 623         vm_offset_t vaddr;
 624         vm_paddr_t paddr, nextpaddr;
 625         bus_dma_segment_t *sg;
 626         bus_addr_t bmask;
 627         int seg, error = 0;
 628
 629         if (map == NULL)
 630                 map = &nobounce_dmamap;
 631
 632 #ifdef INVARIANTS
 633         if (dmat->flags & BUS_DMA_ALIGNED)
 634                 KKASSERT(((uintptr_t)buf & (dmat->alignment - 1)) == 0);
 635 #endif
 636
 637         /*
 638          * If we are being called during a callback, pagesneeded will
 639          * be non-zero, so we can avoid doing the work twice.
 640          */
 641         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 642             map != &nobounce_dmamap && map->pagesneeded == 0) {
 643                 vm_offset_t vendaddr;
 644
 645                 /*
 646                  * Count the number of bounce pages
 647                  * needed in order to complete this transfer
 648                  */
 649                 vaddr = (vm_offset_t)buf;
 650                 vendaddr = (vm_offset_t)buf + buflen;
 651
 652                 while (vaddr < vendaddr) {
 653                         paddr = _bus_dma_extract(pmap, vaddr);
 654                         if (run_filter(dmat, paddr) != 0)
 655                                 map->pagesneeded++;
 656                         vaddr += (PAGE_SIZE - (vaddr & PAGE_MASK));
 657                 }
 658         }
 659
 660         /* Reserve Necessary Bounce Pages */
 661         if (map->pagesneeded != 0) {
 662                 struct bounce_zone *bz;
 663
 664                 bz = dmat->bounce_zone;
 665                 BZ_LOCK(bz);
 666                 if (flags & BUS_DMA_NOWAIT) {
 667                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
 668                                 BZ_UNLOCK(bz);
 669                                 error = ENOMEM;
 670                                 goto free_bounce;
 671                         }
 672                 } else {
 673                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
 674                                 /* Queue us for resources */
 675                                 map->dmat = dmat;
 676                                 map->buf = buf;
 677                                 map->buflen = buflen;
 678
 679                                 STAILQ_INSERT_TAIL(
 680                                     &dmat->bounce_zone->bounce_map_waitinglist,
 681                                     map, links);
 682                                 BZ_UNLOCK(bz);
 683
 684                                 return (EINPROGRESS);
 685                         }
 686                 }
 687                 BZ_UNLOCK(bz);
 688         }
 689
 690         KKASSERT(*segp >= 1 && *segp <= nsegments);
 691         seg = *segp;
 692         sg = &segments[seg - 1];
 693
 694         vaddr = (vm_offset_t)buf;
 695         nextpaddr = *lastpaddrp;
 696         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 697
 698         /* force at least one segment */
 699         do {
 700                 bus_size_t size;
 701
 702                 /*
 703                  * Per-page main loop
 704                  */
 705                 paddr = _bus_dma_extract(pmap, vaddr);
 706                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 707                 if (size > buflen)
 708                         size = buflen;
 709                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 710                         /*
 711                          * note: this paddr has the same in-page offset
 712                          * as vaddr and thus the paddr above, so the
 713                          * size does not have to be recalculated
 714                          */
 715                         paddr = add_bounce_page(dmat, map, vaddr, size);
 716                 }
 717
 718                 /*
 719                  * Fill in the bus_dma_segment
 720                  */
 721                 if (first) {
 722                         sg->ds_addr = paddr;
 723                         sg->ds_len = size;
 724                         first = 0;
 725                 } else if (paddr == nextpaddr) {
 726                         sg->ds_len += size;
 727                 } else {
 728                         sg++;
 729                         seg++;
 730                         if (seg > nsegments)
 731                                 break;
 732                         sg->ds_addr = paddr;
 733                         sg->ds_len = size;
 734                 }
 735                 nextpaddr = paddr + size;
 736
 737                 /*
 738                  * Handle maxsegsz and boundary issues with a nested loop
 739                  */
 740                 for (;;) {
 741                         bus_size_t tmpsize;
 742
 743                         /*
 744                          * Limit to the boundary and maximum segment size
 745                          */
 746                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 747                                 tmpsize = dmat->boundary -
 748                                           (sg->ds_addr & ~bmask);
 749                                 if (tmpsize > dmat->maxsegsz)
 750                                         tmpsize = dmat->maxsegsz;
 751                                 KKASSERT(tmpsize < sg->ds_len);
 752                         } else if (sg->ds_len > dmat->maxsegsz) {
 753                                 tmpsize = dmat->maxsegsz;
 754                         } else {
 755                                 break;
 756                         }
 757
 758                         /*
 759                          * Futz, split the data into a new segment.
 760                          */
 761                         if (seg >= nsegments)
 762                                 goto fail;
 763                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 764                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 765                         sg[0].ds_len = tmpsize;
 766                         sg++;
 767                         seg++;
 768                 }
 769
 770                 /*
 771                  * Adjust for loop
 772                  */
 773                 buflen -= size;
 774                 vaddr += size;
 775         } while (buflen > 0);
 776 fail:
 777         if (buflen != 0)
 778                 error = EFBIG;
 779
 780         *segp = seg;
 781         *lastpaddrp = nextpaddr;
 782
 783 free_bounce:
 784         if (error && (dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 785             map != &nobounce_dmamap) {
 786                 _bus_dmamap_unload(dmat, map);
 787                 return_bounce_pages(dmat, map);
 788         }
 789         return error;
 790 }
 791
 792 /*
 793  * Map the buffer buf into bus space using the dmamap map.
 794  */
 795 int
 796 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 797                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 798                 void *callback_arg, int flags)
 799 {
 800         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 801         bus_dma_segment_t *segments;
 802         vm_paddr_t lastaddr = 0;
 803         int error, nsegs = 1;
 804
 805         if (map != NULL) {
 806                 /*
 807                  * XXX
 808                  * Follow old semantics.  Once all of the callers are fixed,
 809                  * we should get rid of these internal flag "adjustment".
 810                  */
 811                 flags &= ~BUS_DMA_NOWAIT;
 812                 flags |= BUS_DMA_WAITOK;
 813
 814                 map->callback = callback;
 815                 map->callback_arg = callback_arg;
 816         }
 817
 818         segments = bus_dma_tag_lock(dmat, cache_segments);
 819         error = _bus_dmamap_load_buffer(dmat, map, buf, buflen,
 820                         segments, dmat->nsegments,
 821                         NULL, flags, &lastaddr, &nsegs, 1);
 822         if (error == EINPROGRESS) {
 823                 KKASSERT((dmat->flags &
 824                           (BUS_DMA_PRIVBZONE | BUS_DMA_ALLOCALL)) !=
 825                          (BUS_DMA_PRIVBZONE | BUS_DMA_ALLOCALL));
 826
 827                 if (dmat->flags & BUS_DMA_PROTECTED)
 828                         panic("protected dmamap callback will be defered");
 829
 830                 bus_dma_tag_unlock(dmat);
 831                 return error;
 832         }
 833         callback(callback_arg, segments, nsegs, error);
 834         bus_dma_tag_unlock(dmat);
 835         return 0;
 836 }
 837
 838 /*
 839  * Like _bus_dmamap_load(), but for mbufs.
 840  */
 841 int
 842 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 843                      struct mbuf *m0,
 844                      bus_dmamap_callback2_t *callback, void *callback_arg,
 845                      int flags)
 846 {
 847         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 848         bus_dma_segment_t *segments;
 849         int nsegs, error;
 850
 851         /*
 852          * XXX
 853          * Follow old semantics.  Once all of the callers are fixed,
 854          * we should get rid of these internal flag "adjustment".
 855          */
 856         flags &= ~BUS_DMA_WAITOK;
 857         flags |= BUS_DMA_NOWAIT;
 858
 859         segments = bus_dma_tag_lock(dmat, cache_segments);
 860         error = bus_dmamap_load_mbuf_segment(dmat, map, m0,
 861                         segments, dmat->nsegments, &nsegs, flags);
 862         if (error) {
 863                 /* force "no valid mappings" in callback */
 864                 callback(callback_arg, segments, 0,
 865                          0, error);
 866         } else {
 867                 callback(callback_arg, segments, nsegs,
 868                          m0->m_pkthdr.len, error);
 869         }
 870         bus_dma_tag_unlock(dmat);
 871         return error;
 872 }
 873
 874 int
 875 bus_dmamap_load_mbuf_segment(bus_dma_tag_t dmat, bus_dmamap_t map,
 876                              struct mbuf *m0,
 877                              bus_dma_segment_t *segs, int maxsegs,
 878                              int *nsegs, int flags)
 879 {
 880         int error;
 881
 882         M_ASSERTPKTHDR(m0);
 883
 884         KASSERT(maxsegs >= 1, ("invalid maxsegs %d", maxsegs));
 885         KASSERT(maxsegs <= dmat->nsegments,
 886                 ("%d too many segments, dmat only supports %d segments",
 887                  maxsegs, dmat->nsegments));
 888         KASSERT(flags & BUS_DMA_NOWAIT,
 889                 ("only BUS_DMA_NOWAIT is supported"));
 890
 891         if (m0->m_pkthdr.len <= dmat->maxsize) {
 892                 int first = 1;
 893                 vm_paddr_t lastaddr = 0;
 894                 struct mbuf *m;
 895
 896                 *nsegs = 1;
 897                 error = 0;
 898                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 899                         if (m->m_len == 0)
 900                                 continue;
 901
 902                         error = _bus_dmamap_load_buffer(dmat, map,
 903                                         m->m_data, m->m_len,
 904                                         segs, maxsegs,
 905                                         NULL, flags, &lastaddr,
 906                                         nsegs, first);
 907                         if (error == ENOMEM && !first) {
 908                                 /*
 909                                  * Out of bounce pages due to too many
 910                                  * fragments in the mbuf chain; return
 911                                  * EFBIG instead.
 912                                  */
 913                                 error = EFBIG;
 914                         }
 915                         first = 0;
 916                 }
 917 #ifdef INVARIANTS
 918                 if (!error)
 919                         KKASSERT(*nsegs <= maxsegs && *nsegs >= 1);
 920 #endif
 921         } else {
 922                 *nsegs = 0;
 923                 error = EINVAL;
 924         }
 925         KKASSERT(error != EINPROGRESS);
 926         return error;
 927 }
 928
 929 /*
 930  * Like _bus_dmamap_load(), but for uios.
 931  */
 932 int
 933 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 934                     struct uio *uio,
 935                     bus_dmamap_callback2_t *callback, void *callback_arg,
 936                     int flags)
 937 {
 938         vm_paddr_t lastaddr;
 939         int nsegs, error, first, i;
 940         bus_size_t resid;
 941         struct iovec *iov;
 942         pmap_t pmap;
 943         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 944         bus_dma_segment_t *segments;
 945         bus_dma_segment_t *segs;
 946         int nsegs_left;
 947
 948         if (dmat->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 949                 segments = cache_segments;
 950         else
 951                 segments = kmalloc(sizeof(bus_dma_segment_t) * dmat->nsegments,
 952                                    M_DEVBUF, M_WAITOK | M_ZERO);
 953
 954         /*
 955          * XXX
 956          * Follow old semantics.  Once all of the callers are fixed,
 957          * we should get rid of these internal flag "adjustment".
 958          */
 959         flags &= ~BUS_DMA_WAITOK;
 960         flags |= BUS_DMA_NOWAIT;
 961
 962         resid = (bus_size_t)uio->uio_resid;
 963         iov = uio->uio_iov;
 964
 965         segs = segments;
 966         nsegs_left = dmat->nsegments;
 967
 968         if (uio->uio_segflg == UIO_USERSPACE) {
 969                 struct thread *td;
 970
 971                 td = uio->uio_td;
 972                 KASSERT(td != NULL && td->td_proc != NULL,
 973                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 974                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 975         } else {
 976                 pmap = NULL;
 977         }
 978
 979         error = 0;
 980         nsegs = 1;
 981         first = 1;
 982         lastaddr = 0;
 983         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 984                 /*
 985                  * Now at the first iovec to load.  Load each iovec
 986                  * until we have exhausted the residual count.
 987                  */
 988                 bus_size_t minlen =
 989                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 990                 caddr_t addr = (caddr_t) iov[i].iov_base;
 991
 992                 error = _bus_dmamap_load_buffer(dmat, map, addr, minlen,
 993                                 segs, nsegs_left,
 994                                 pmap, flags, &lastaddr, &nsegs, first);
 995                 first = 0;
 996
 997                 resid -= minlen;
 998                 if (error == 0) {
 999                         nsegs_left -= nsegs;
1000                         segs += nsegs;
1001                 }
1002         }
1003
1004         /*
1005          * Minimum one DMA segment, even if 0-length buffer.
1006          */
1007         if (nsegs_left == dmat->nsegments)
1008                 --nsegs_left;
1009
1010         if (error) {
1011                 /* force "no valid mappings" in callback */
1012                 callback(callback_arg, segments, 0,
1013                          0, error);
1014         } else {
1015                 callback(callback_arg, segments, dmat->nsegments - nsegs_left,
1016                          (bus_size_t)uio->uio_resid, error);
1017         }
1018         if (dmat->nsegments > BUS_DMA_CACHE_SEGMENTS)
1019                 kfree(segments, M_DEVBUF);
1020         return error;
1021 }
1022
1023 /*
1024  * Release the mapping held by map.
1025  */
1026 void
1027 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
1028 {
1029         struct bounce_page *bpage;
1030
1031         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1032                 STAILQ_REMOVE_HEAD(&map->bpages, links);
1033                 free_bounce_page(dmat, bpage);
1034         }
1035 }
1036
1037 void
1038 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
1039 {
1040         struct bounce_page *bpage;
1041
1042         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1043                 /*
1044                  * Handle data bouncing.  We might also
1045                  * want to add support for invalidating
1046                  * the caches on broken hardware
1047                  */
1048                 switch (op) {
1049                 case BUS_DMASYNC_PREWRITE:
1050                         while (bpage != NULL) {
1051                                 bcopy((void *)bpage->datavaddr,
1052                                       (void *)bpage->vaddr,
1053                                       bpage->datacount);
1054                                 bpage = STAILQ_NEXT(bpage, links);
1055                         }
1056                         dmat->bounce_zone->total_bounced++;
1057                         break;
1058
1059                 case BUS_DMASYNC_POSTREAD:
1060                         while (bpage != NULL) {
1061                                 bcopy((void *)bpage->vaddr,
1062                                       (void *)bpage->datavaddr,
1063                                       bpage->datacount);
1064                                 bpage = STAILQ_NEXT(bpage, links);
1065                         }
1066                         dmat->bounce_zone->total_bounced++;
1067                         break;
1068
1069                 case BUS_DMASYNC_PREREAD:
1070                 case BUS_DMASYNC_POSTWRITE:
1071                         /* No-ops */
1072                         break;
1073                 }
1074         }
1075 }
1076
1077 static int
1078 alloc_bounce_zone(bus_dma_tag_t dmat)
1079 {
1080         struct bounce_zone *bz, *new_bz;
1081
1082         KASSERT(dmat->bounce_zone == NULL,
1083                 ("bounce zone was already assigned"));
1084
1085         new_bz = kmalloc(sizeof(*new_bz), M_DEVBUF, M_INTWAIT | M_ZERO);
1086
1087         lwkt_gettoken(&bounce_zone_tok);
1088
1089         if ((dmat->flags & BUS_DMA_PRIVBZONE) == 0) {
1090                 /*
1091                  * For shared bounce zone, check to see
1092                  * if we already have a suitable zone
1093                  */
1094                 STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1095                         if (dmat->alignment <= bz->alignment &&
1096                             dmat->lowaddr >= bz->lowaddr) {
1097                                 lwkt_reltoken(&bounce_zone_tok);
1098
1099                                 dmat->bounce_zone = bz;
1100                                 kfree(new_bz, M_DEVBUF);
1101                                 return 0;
1102                         }
1103                 }
1104         }
1105         bz = new_bz;
1106
1107         spin_init(&bz->spin);
1108         STAILQ_INIT(&bz->bounce_page_list);
1109         STAILQ_INIT(&bz->bounce_map_waitinglist);
1110         bz->free_bpages = 0;
1111         bz->reserved_bpages = 0;
1112         bz->active_bpages = 0;
1113         bz->lowaddr = dmat->lowaddr;
1114         bz->alignment = round_page(dmat->alignment);
1115         ksnprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1116
1117         if ((dmat->flags & BUS_DMA_PRIVBZONE) == 0) {
1118                 ksnprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1119                 busdma_zonecount++;
1120                 STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1121         } else {
1122                 ksnprintf(bz->zoneid, 8, "zone%d", busdma_priv_zonecount);
1123                 busdma_priv_zonecount--;
1124         }
1125
1126         lwkt_reltoken(&bounce_zone_tok);
1127
1128         dmat->bounce_zone = bz;
1129
1130         sysctl_ctx_init(&bz->sysctl_ctx);
1131         bz->sysctl_tree = SYSCTL_ADD_NODE(&bz->sysctl_ctx,
1132             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1133             CTLFLAG_RD, 0, "");
1134         if (bz->sysctl_tree == NULL) {
1135                 sysctl_ctx_free(&bz->sysctl_ctx);
1136                 return 0;       /* XXX error code? */
1137         }
1138
1139         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1140             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1141             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1142             "Total bounce pages");
1143         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1144             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1145             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1146             "Free bounce pages");
1147         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1148             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1149             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1150             "Reserved bounce pages");
1151         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1152             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1153             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1154             "Active bounce pages");
1155         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1156             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1157             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1158             "Total bounce requests");
1159         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1160             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1161             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1162             "Total bounce requests that were deferred");
1163         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1164             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1165             "reserve_failed", CTLFLAG_RD, &bz->reserve_failed, 0,
1166             "Total bounce page reservations that were failed");
1167         SYSCTL_ADD_STRING(&bz->sysctl_ctx,
1168             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1169             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1170         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1171             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1172             "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
1173
1174         return 0;
1175 }
1176
1177 static int
1178 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages, int flags)
1179 {
1180         struct bounce_zone *bz = dmat->bounce_zone;
1181         int count = 0, mflags;
1182
1183         if (flags & BUS_DMA_NOWAIT)
1184                 mflags = M_NOWAIT;
1185         else
1186                 mflags = M_WAITOK;
1187
1188         while (numpages > 0) {
1189                 struct bounce_page *bpage;
1190
1191                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
1192
1193                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1194                                                          mflags, 0ul,
1195                                                          bz->lowaddr,
1196                                                          bz->alignment, 0);
1197                 if (bpage->vaddr == 0) {
1198                         kfree(bpage, M_DEVBUF);
1199                         break;
1200                 }
1201                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1202
1203                 BZ_LOCK(bz);
1204                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1205                 total_bounce_pages++;
1206                 bz->total_bpages++;
1207                 bz->free_bpages++;
1208                 BZ_UNLOCK(bz);
1209
1210                 count++;
1211                 numpages--;
1212         }
1213         return count;
1214 }
1215
1216 static void
1217 free_bounce_pages_all(bus_dma_tag_t dmat)
1218 {
1219         struct bounce_zone *bz = dmat->bounce_zone;
1220         struct bounce_page *bpage;
1221
1222         BZ_LOCK(bz);
1223
1224         while ((bpage = STAILQ_FIRST(&bz->bounce_page_list)) != NULL) {
1225                 STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1226
1227                 KKASSERT(total_bounce_pages > 0);
1228                 total_bounce_pages--;
1229
1230                 KKASSERT(bz->total_bpages > 0);
1231                 bz->total_bpages--;
1232
1233                 KKASSERT(bz->free_bpages > 0);
1234                 bz->free_bpages--;
1235
1236                 BZ_UNLOCK(bz);
1237                 contigfree((void *)bpage->vaddr, PAGE_SIZE, M_DEVBUF);
1238                 kfree(bpage, M_DEVBUF);
1239                 BZ_LOCK(bz);
1240         }
1241         if (bz->total_bpages) {
1242                 kprintf("#%d bounce pages are still in use\n",
1243                         bz->total_bpages);
1244                 print_backtrace(-1);
1245         }
1246
1247         BZ_UNLOCK(bz);
1248 }
1249
1250 static void
1251 free_bounce_zone(bus_dma_tag_t dmat)
1252 {
1253         struct bounce_zone *bz = dmat->bounce_zone;
1254
1255         if (bz == NULL)
1256                 return;
1257
1258         if ((dmat->flags & BUS_DMA_PRIVBZONE) == 0)
1259                 return;
1260
1261         free_bounce_pages_all(dmat);
1262         dmat->bounce_zone = NULL;
1263
1264         if (bz->sysctl_tree != NULL)
1265                 sysctl_ctx_free(&bz->sysctl_ctx);
1266         kfree(bz, M_DEVBUF);
1267 }
1268
1269 /* Assume caller holds bounce zone spinlock */
1270 static int
1271 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1272 {
1273         struct bounce_zone *bz = dmat->bounce_zone;
1274         int pages;
1275
1276         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1277         if (!commit && map->pagesneeded > (map->pagesreserved + pages)) {
1278                 bz->reserve_failed++;
1279                 return (map->pagesneeded - (map->pagesreserved + pages));
1280         }
1281
1282         bz->free_bpages -= pages;
1283
1284         bz->reserved_bpages += pages;
1285         KKASSERT(bz->reserved_bpages <= bz->total_bpages);
1286
1287         map->pagesreserved += pages;
1288         pages = map->pagesneeded - map->pagesreserved;
1289
1290         return pages;
1291 }
1292
1293 static void
1294 return_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
1295 {
1296         struct bounce_zone *bz = dmat->bounce_zone;
1297         int reserved = map->pagesreserved;
1298         bus_dmamap_t wait_map;
1299
1300         map->pagesreserved = 0;
1301         map->pagesneeded = 0;
1302
1303         if (reserved == 0)
1304                 return;
1305
1306         BZ_LOCK(bz);
1307
1308         bz->free_bpages += reserved;
1309         KKASSERT(bz->free_bpages <= bz->total_bpages);
1310
1311         KKASSERT(bz->reserved_bpages >= reserved);
1312         bz->reserved_bpages -= reserved;
1313
1314         wait_map = get_map_waiting(dmat);
1315
1316         BZ_UNLOCK(bz);
1317
1318         if (wait_map != NULL)
1319                 add_map_callback(map);
1320 }
1321
1322 static bus_addr_t
1323 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1324                 bus_size_t size)
1325 {
1326         struct bounce_zone *bz = dmat->bounce_zone;
1327         struct bounce_page *bpage;
1328
1329         KASSERT(map->pagesneeded > 0, ("map doesn't need any pages"));
1330         map->pagesneeded--;
1331
1332         KASSERT(map->pagesreserved > 0, ("map doesn't reserve any pages"));
1333         map->pagesreserved--;
1334
1335         BZ_LOCK(bz);
1336
1337         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1338         KASSERT(bpage != NULL, ("free page list is empty"));
1339         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1340
1341         KKASSERT(bz->reserved_bpages > 0);
1342         bz->reserved_bpages--;
1343
1344         bz->active_bpages++;
1345         KKASSERT(bz->active_bpages <= bz->total_bpages);
1346
1347         BZ_UNLOCK(bz);
1348
1349         if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
1350                 /* Page offset needs to be preserved. */
1351                 bpage->vaddr |= vaddr & PAGE_MASK;
1352                 bpage->busaddr |= vaddr & PAGE_MASK;
1353         }
1354
1355         bpage->datavaddr = vaddr;
1356         bpage->datacount = size;
1357         STAILQ_INSERT_TAIL(&map->bpages, bpage, links);
1358         return bpage->busaddr;
1359 }
1360
1361 static void
1362 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1363 {
1364         struct bounce_zone *bz = dmat->bounce_zone;
1365         bus_dmamap_t map;
1366
1367         bpage->datavaddr = 0;
1368         bpage->datacount = 0;
1369
1370         if (dmat->flags & BUS_DMA_KEEP_PG_OFFSET) {
1371                 /*
1372                  * Reset the bounce page to start at offset 0.  Other uses
1373                  * of this bounce page may need to store a full page of
1374                  * data and/or assume it starts on a page boundary.
1375                  */
1376                 bpage->vaddr &= ~PAGE_MASK;
1377                 bpage->busaddr &= ~PAGE_MASK;
1378         }
1379
1380         BZ_LOCK(bz);
1381
1382         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1383
1384         bz->free_bpages++;
1385         KKASSERT(bz->free_bpages <= bz->total_bpages);
1386
1387         KKASSERT(bz->active_bpages > 0);
1388         bz->active_bpages--;
1389
1390         map = get_map_waiting(dmat);
1391
1392         BZ_UNLOCK(bz);
1393
1394         if (map != NULL)
1395                 add_map_callback(map);
1396 }
1397
1398 /* Assume caller holds bounce zone spinlock */
1399 static bus_dmamap_t
1400 get_map_waiting(bus_dma_tag_t dmat)
1401 {
1402         struct bounce_zone *bz = dmat->bounce_zone;
1403         bus_dmamap_t map;
1404
1405         map = STAILQ_FIRST(&bz->bounce_map_waitinglist);
1406         if (map != NULL) {
1407                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1408                         STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
1409                         bz->total_deferred++;
1410                 } else {
1411                         map = NULL;
1412                 }
1413         }
1414         return map;
1415 }
1416
1417 static void
1418 add_map_callback(bus_dmamap_t map)
1419 {
1420         spin_lock(&bounce_map_list_spin);
1421         STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
1422         busdma_swi_pending = 1;
1423         setsoftvm();
1424         spin_unlock(&bounce_map_list_spin);
1425 }
1426
1427 void
1428 busdma_swi(void)
1429 {
1430         bus_dmamap_t map;
1431
1432         spin_lock(&bounce_map_list_spin);
1433         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1434                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1435                 spin_unlock(&bounce_map_list_spin);
1436                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
1437                                 map->callback, map->callback_arg, /*flags*/0);
1438                 spin_lock(&bounce_map_list_spin);
1439         }
1440         spin_unlock(&bounce_map_list_spin);
1441 }