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  * $DragonFly: src/sys/platform/pc32/i386/busdma_machdep.c,v 1.23 2008/06/05 18:06:32 swildner Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/malloc.h>
  33 #include <sys/mbuf.h>
  34 #include <sys/uio.h>
  35 #include <sys/bus_dma.h>
  36 #include <sys/kernel.h>
  37 #include <sys/sysctl.h>
  38 #include <sys/lock.h>
  39
  40 #include <sys/thread2.h>
  41 #include <sys/spinlock2.h>
  42 #include <sys/mplock2.h>
  43
  44 #include <vm/vm.h>
  45 #include <vm/vm_page.h>
  46
  47 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  48 #include <sys/proc.h>
  49 #include <sys/lock.h>
  50 #include <vm/vm_map.h>
  51
  52 #include <machine/md_var.h>
  53
  54 #define MAX_BPAGES      1024
  55
  56 /*
  57  * 16 x N declared on stack.
  58  */
  59 #define BUS_DMA_CACHE_SEGMENTS  8
  60
  61 struct bounce_zone;
  62 struct bus_dmamap;
  63
  64 struct bus_dma_tag {
  65         bus_dma_tag_t   parent;
  66         bus_size_t      alignment;
  67         bus_size_t      boundary;
  68         bus_addr_t      lowaddr;
  69         bus_addr_t      highaddr;
  70         bus_dma_filter_t *filter;
  71         void            *filterarg;
  72         bus_size_t      maxsize;
  73         u_int           nsegments;
  74         bus_size_t      maxsegsz;
  75         int             flags;
  76         int             ref_count;
  77         int             map_count;
  78         bus_dma_segment_t *segments;
  79         struct bounce_zone *bounce_zone;
  80 #ifdef SMP
  81         struct spinlock spin;
  82 #else
  83         int             unused0;
  84 #endif
  85 };
  86
  87 /*
  88  * bus_dma_tag private flags
  89  */
  90 #define BUS_DMA_BOUNCE_ALIGN    BUS_DMA_BUS2
  91 #define BUS_DMA_BOUNCE_LOWADDR  BUS_DMA_BUS3
  92 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  93
  94 #define BUS_DMA_COULD_BOUNCE    (BUS_DMA_BOUNCE_LOWADDR | BUS_DMA_BOUNCE_ALIGN)
  95
  96 #define BUS_DMAMEM_KMALLOC(dmat) \
  97         ((dmat)->maxsize <= PAGE_SIZE && \
  98          (dmat)->alignment <= PAGE_SIZE && \
  99          (dmat)->lowaddr >= ptoa(Maxmem))
 100
 101 struct bounce_page {
 102         vm_offset_t     vaddr;          /* kva of bounce buffer */
 103         bus_addr_t      busaddr;        /* Physical address */
 104         vm_offset_t     datavaddr;      /* kva of client data */
 105         bus_size_t      datacount;      /* client data count */
 106         STAILQ_ENTRY(bounce_page) links;
 107 };
 108
 109 struct bounce_zone {
 110         STAILQ_ENTRY(bounce_zone) links;
 111         STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
 112         STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 113 #ifdef SMP
 114         struct spinlock spin;
 115 #else
 116         int             unused0;
 117 #endif
 118         int             total_bpages;
 119         int             free_bpages;
 120         int             reserved_bpages;
 121         int             active_bpages;
 122         int             total_bounced;
 123         int             total_deferred;
 124         int             reserve_failed;
 125         bus_size_t      alignment;
 126         bus_addr_t      lowaddr;
 127         char            zoneid[8];
 128         char            lowaddrid[20];
 129         struct sysctl_ctx_list sysctl_ctx;
 130         struct sysctl_oid *sysctl_tree;
 131 };
 132
 133 #ifdef SMP
 134 #define BZ_LOCK(bz)     spin_lock(&(bz)->spin)
 135 #define BZ_UNLOCK(bz)   spin_unlock(&(bz)->spin)
 136 #else
 137 #define BZ_LOCK(bz)     crit_enter()
 138 #define BZ_UNLOCK(bz)   crit_exit()
 139 #endif
 140
 141 static struct lwkt_token bounce_zone_tok =
 142         LWKT_TOKEN_MP_INITIALIZER(bounce_zone_token);
 143 static int busdma_zonecount;
 144 static STAILQ_HEAD(, bounce_zone) bounce_zone_list =
 145         STAILQ_HEAD_INITIALIZER(bounce_zone_list);
 146
 147 int busdma_swi_pending;
 148 static int total_bounce_pages;
 149 static int max_bounce_pages = MAX_BPAGES;
 150 static int bounce_alignment = 1; /* XXX temporary */
 151
 152 TUNABLE_INT("hw.busdma.max_bpages", &max_bounce_pages);
 153 TUNABLE_INT("hw.busdma.bounce_alignment", &bounce_alignment);
 154
 155 struct bus_dmamap {
 156         struct bp_list  bpages;
 157         int             pagesneeded;
 158         int             pagesreserved;
 159         bus_dma_tag_t   dmat;
 160         void            *buf;           /* unmapped buffer pointer */
 161         bus_size_t      buflen;         /* unmapped buffer length */
 162         bus_dmamap_callback_t *callback;
 163         void            *callback_arg;
 164         STAILQ_ENTRY(bus_dmamap) links;
 165 };
 166
 167 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist =
 168         STAILQ_HEAD_INITIALIZER(bounce_map_callbacklist);
 169 static struct spinlock bounce_map_list_spin =
 170         SPINLOCK_INITIALIZER(&bounce_map_list_spin);
 171
 172 static struct bus_dmamap nobounce_dmamap;
 173
 174 static int              alloc_bounce_zone(bus_dma_tag_t);
 175 static int              alloc_bounce_pages(bus_dma_tag_t, u_int, int);
 176 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
 177 static void             return_bounce_pages(bus_dma_tag_t, bus_dmamap_t);
 178 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
 179                             vm_offset_t, bus_size_t);
 180 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
 181
 182 static bus_dmamap_t     get_map_waiting(bus_dma_tag_t);
 183 static void             add_map_callback(bus_dmamap_t);
 184
 185 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 186 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bounce_pages,
 187            0, "Total bounce pages");
 188 SYSCTL_INT(_hw_busdma, OID_AUTO, max_bpages, CTLFLAG_RD, &max_bounce_pages,
 189            0, "Max bounce pages per bounce zone");
 190 SYSCTL_INT(_hw_busdma, OID_AUTO, bounce_alignment, CTLFLAG_RD,
 191            &bounce_alignment, 0, "Obey alignment constraint");
 192
 193 static __inline int
 194 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 195 {
 196         int retval;
 197
 198         retval = 0;
 199         do {
 200                 if (((paddr > dmat->lowaddr && paddr <= dmat->highaddr) ||
 201                      (bounce_alignment && (paddr & (dmat->alignment - 1)) != 0))
 202                  && (dmat->filter == NULL ||
 203                      dmat->filter(dmat->filterarg, paddr) != 0))
 204                         retval = 1;
 205
 206                 dmat = dmat->parent;
 207         } while (retval == 0 && dmat != NULL);
 208         return (retval);
 209 }
 210
 211 static __inline
 212 bus_dma_segment_t *
 213 bus_dma_tag_lock(bus_dma_tag_t tag, bus_dma_segment_t *cache)
 214 {
 215         if (tag->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 216                 return(cache);
 217 #ifdef SMP
 218         spin_lock(&tag->spin);
 219 #endif
 220         return(tag->segments);
 221 }
 222
 223 static __inline
 224 void
 225 bus_dma_tag_unlock(bus_dma_tag_t tag)
 226 {
 227 #ifdef SMP
 228         if (tag->nsegments > BUS_DMA_CACHE_SEGMENTS)
 229                 spin_unlock(&tag->spin);
 230 #endif
 231 }
 232
 233 /*
 234  * Allocate a device specific dma_tag.
 235  */
 236 int
 237 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 238                    bus_size_t boundary, bus_addr_t lowaddr,
 239                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 240                    void *filterarg, bus_size_t maxsize, int nsegments,
 241                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 242 {
 243         bus_dma_tag_t newtag;
 244         int error = 0;
 245
 246         /*
 247          * Sanity checks
 248          */
 249
 250         if (alignment == 0)
 251                 alignment = 1;
 252         if (alignment & (alignment - 1))
 253                 panic("alignment must be power of 2\n");
 254
 255         if (boundary != 0) {
 256                 if (boundary & (boundary - 1))
 257                         panic("boundary must be power of 2\n");
 258                 if (boundary < maxsegsz) {
 259                         kprintf("boundary < maxsegsz:\n");
 260                         print_backtrace(-1);
 261                         maxsegsz = boundary;
 262                 }
 263         }
 264
 265         /* Return a NULL tag on failure */
 266         *dmat = NULL;
 267
 268         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT | M_ZERO);
 269
 270 #ifdef SMP
 271         spin_init(&newtag->spin);
 272 #endif
 273         newtag->parent = parent;
 274         newtag->alignment = alignment;
 275         newtag->boundary = boundary;
 276         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 277         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 278         newtag->filter = filter;
 279         newtag->filterarg = filterarg;
 280         newtag->maxsize = maxsize;
 281         newtag->nsegments = nsegments;
 282         newtag->maxsegsz = maxsegsz;
 283         newtag->flags = flags;
 284         newtag->ref_count = 1; /* Count ourself */
 285         newtag->map_count = 0;
 286         newtag->segments = NULL;
 287         newtag->bounce_zone = NULL;
 288
 289         /* Take into account any restrictions imposed by our parent tag */
 290         if (parent != NULL) {
 291                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 292                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 293
 294                 if (newtag->boundary == 0) {
 295                         newtag->boundary = parent->boundary;
 296                 } else if (parent->boundary != 0) {
 297                         newtag->boundary = MIN(parent->boundary,
 298                                                newtag->boundary);
 299                 }
 300
 301 #ifdef notyet
 302                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
 303 #endif
 304
 305                 if (newtag->filter == NULL) {
 306                         /*
 307                          * Short circuit looking at our parent directly
 308                          * since we have encapsulated all of its information
 309                          */
 310                         newtag->filter = parent->filter;
 311                         newtag->filterarg = parent->filterarg;
 312                         newtag->parent = parent->parent;
 313                 }
 314                 if (newtag->parent != NULL)
 315                         parent->ref_count++;
 316         }
 317
 318         if (newtag->lowaddr < ptoa(Maxmem))
 319                 newtag->flags |= BUS_DMA_BOUNCE_LOWADDR;
 320         if (bounce_alignment && newtag->alignment > 1 &&
 321             !(newtag->flags & BUS_DMA_ALIGNED))
 322                 newtag->flags |= BUS_DMA_BOUNCE_ALIGN;
 323
 324         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
 325             (flags & BUS_DMA_ALLOCNOW) != 0) {
 326                 struct bounce_zone *bz;
 327
 328                 /* Must bounce */
 329
 330                 error = alloc_bounce_zone(newtag);
 331                 if (error)
 332                         goto back;
 333                 bz = newtag->bounce_zone;
 334
 335                 if (ptoa(bz->total_bpages) < maxsize) {
 336                         int pages;
 337
 338                         if (flags & BUS_DMA_ONEBPAGE) {
 339                                 pages = 1;
 340                         } else {
 341                                 pages = atop(round_page(maxsize)) -
 342                                         bz->total_bpages;
 343                                 pages = MAX(pages, 1);
 344                         }
 345
 346                         /* Add pages to our bounce pool */
 347                         if (alloc_bounce_pages(newtag, pages, flags) < pages)
 348                                 error = ENOMEM;
 349
 350                         /* Performed initial allocation */
 351                         newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 352                 }
 353         }
 354 back:
 355         if (error)
 356                 kfree(newtag, M_DEVBUF);
 357         else
 358                 *dmat = newtag;
 359         return error;
 360 }
 361
 362 int
 363 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 364 {
 365         if (dmat != NULL) {
 366                 if (dmat->map_count != 0)
 367                         return (EBUSY);
 368
 369                 while (dmat != NULL) {
 370                         bus_dma_tag_t parent;
 371
 372                         parent = dmat->parent;
 373                         dmat->ref_count--;
 374                         if (dmat->ref_count == 0) {
 375                                 if (dmat->segments != NULL)
 376                                         kfree(dmat->segments, M_DEVBUF);
 377                                 kfree(dmat, M_DEVBUF);
 378                                 /*
 379                                  * Last reference count, so
 380                                  * release our reference
 381                                  * count on our parent.
 382                                  */
 383                                 dmat = parent;
 384                         } else
 385                                 dmat = NULL;
 386                 }
 387         }
 388         return (0);
 389 }
 390
 391 bus_size_t
 392 bus_dma_tag_getmaxsize(bus_dma_tag_t tag)
 393 {
 394         return(tag->maxsize);
 395 }
 396
 397 /*
 398  * Allocate a handle for mapping from kva/uva/physical
 399  * address space into bus device space.
 400  */
 401 int
 402 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 403 {
 404         int error;
 405
 406         error = 0;
 407
 408         if (dmat->segments == NULL) {
 409                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 410                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 411                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 412         }
 413
 414         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 415                 struct bounce_zone *bz;
 416                 int maxpages;
 417
 418                 /* Must bounce */
 419
 420                 if (dmat->bounce_zone == NULL) {
 421                         error = alloc_bounce_zone(dmat);
 422                         if (error)
 423                                 return error;
 424                 }
 425                 bz = dmat->bounce_zone;
 426
 427                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
 428
 429                 /* Initialize the new map */
 430                 STAILQ_INIT(&((*mapp)->bpages));
 431
 432                 /*
 433                  * Attempt to add pages to our pool on a per-instance
 434                  * basis up to a sane limit.
 435                  */
 436                 if (dmat->flags & BUS_DMA_BOUNCE_ALIGN) {
 437                         maxpages = max_bounce_pages;
 438                 } else {
 439                         maxpages = MIN(max_bounce_pages,
 440                                        Maxmem - atop(dmat->lowaddr));
 441                 }
 442                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 443                  || (dmat->map_count > 0
 444                   && bz->total_bpages < maxpages)) {
 445                         int pages;
 446
 447                         if (flags & BUS_DMA_ONEBPAGE) {
 448                                 pages = 1;
 449                         } else {
 450                                 pages = atop(round_page(dmat->maxsize));
 451                                 pages = MIN(maxpages - bz->total_bpages, pages);
 452                                 pages = MAX(pages, 1);
 453                         }
 454                         if (alloc_bounce_pages(dmat, pages, flags) < pages)
 455                                 error = ENOMEM;
 456
 457                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 458                                 if (!error)
 459                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 460                         } else {
 461                                 error = 0;
 462                         }
 463                 }
 464         } else {
 465                 *mapp = NULL;
 466         }
 467         if (!error)
 468                 dmat->map_count++;
 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 || bootverbose)
 496                         kprintf("boundary check failed\n");
 497                 if (verify)
 498                         print_backtrace(-1); /* XXX panic */
 499                 maxsize = dmat->maxsize;
 500         }
 501         if (vaddr & (dmat->alignment - 1)) {
 502                 if (verify || bootverbose)
 503                         kprintf("alignment check failed\n");
 504                 if (verify)
 505                         print_backtrace(-1); /* XXX panic */
 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                         size_t size;
 558
 559                         kfree(*vaddr, M_DEVBUF);
 560                         /* XXX check for overflow? */
 561                         for (size = 1; size <= maxsize; size <<= 1)
 562                                 ;
 563                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 564                         check_kmalloc(dmat, *vaddr, 1);
 565                 }
 566         } else {
 567                 /*
 568                  * XXX Use Contigmalloc until it is merged into this facility
 569                  *     and handles multi-seg allocations.  Nobody is doing
 570                  *     multi-seg allocations yet though.
 571                  */
 572                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 573                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
 574         }
 575         if (*vaddr == NULL)
 576                 return (ENOMEM);
 577         return (0);
 578 }
 579
 580 /*
 581  * Free a piece of memory and it's allociated dmamap, that was allocated
 582  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 583  */
 584 void
 585 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 586 {
 587         /*
 588          * dmamem does not need to be bounced, so the map should be
 589          * NULL
 590          */
 591         if (map != NULL)
 592                 panic("bus_dmamem_free: Invalid map freed\n");
 593         if (BUS_DMAMEM_KMALLOC(dmat))
 594                 kfree(vaddr, M_DEVBUF);
 595         else
 596                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 597 }
 598
 599 static __inline vm_paddr_t
 600 _bus_dma_extract(pmap_t pmap, vm_offset_t vaddr)
 601 {
 602         if (pmap)
 603                 return pmap_extract(pmap, vaddr);
 604         else
 605                 return pmap_kextract(vaddr);
 606 }
 607
 608 /*
 609  * Utility function to load a linear buffer.  lastaddrp holds state
 610  * between invocations (for multiple-buffer loads).  segp contains
 611  * the segment following the starting one on entrace, and the ending
 612  * segment on exit.  first indicates if this is the first invocation
 613  * of this function.
 614  */
 615 static int
 616 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 617                         bus_dmamap_t map,
 618                         void *buf, bus_size_t buflen,
 619                         bus_dma_segment_t *segments,
 620                         int nsegments,
 621                         pmap_t pmap,
 622                         int flags,
 623                         vm_paddr_t *lastpaddrp,
 624                         int *segp,
 625                         int first)
 626 {
 627         vm_offset_t vaddr;
 628         vm_paddr_t paddr, nextpaddr;
 629         bus_dma_segment_t *sg;
 630         bus_addr_t bmask;
 631         int seg, error = 0;
 632
 633         if (map == NULL)
 634                 map = &nobounce_dmamap;
 635
 636 #ifdef INVARIANTS
 637         if (dmat->flags & BUS_DMA_ALIGNED)
 638                 KKASSERT(((uintptr_t)buf & (dmat->alignment - 1)) == 0);
 639 #endif
 640
 641         /*
 642          * If we are being called during a callback, pagesneeded will
 643          * be non-zero, so we can avoid doing the work twice.
 644          */
 645         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 646             map != &nobounce_dmamap && map->pagesneeded == 0) {
 647                 vm_offset_t vendaddr;
 648
 649                 /*
 650                  * Count the number of bounce pages
 651                  * needed in order to complete this transfer
 652                  */
 653                 vaddr = (vm_offset_t)buf;
 654                 vendaddr = (vm_offset_t)buf + buflen;
 655
 656                 while (vaddr < vendaddr) {
 657                         paddr = _bus_dma_extract(pmap, vaddr);
 658                         if (run_filter(dmat, paddr) != 0)
 659                                 map->pagesneeded++;
 660                         vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
 661                 }
 662         }
 663
 664         /* Reserve Necessary Bounce Pages */
 665         if (map->pagesneeded != 0) {
 666                 struct bounce_zone *bz;
 667
 668                 bz = dmat->bounce_zone;
 669                 BZ_LOCK(bz);
 670                 if (flags & BUS_DMA_NOWAIT) {
 671                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
 672                                 BZ_UNLOCK(bz);
 673                                 error = ENOMEM;
 674                                 goto free_bounce;
 675                         }
 676                 } else {
 677                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
 678                                 /* Queue us for resources */
 679                                 map->dmat = dmat;
 680                                 map->buf = buf;
 681                                 map->buflen = buflen;
 682
 683                                 STAILQ_INSERT_TAIL(
 684                                     &dmat->bounce_zone->bounce_map_waitinglist,
 685                                     map, links);
 686                                 BZ_UNLOCK(bz);
 687
 688                                 return (EINPROGRESS);
 689                         }
 690                 }
 691                 BZ_UNLOCK(bz);
 692         }
 693
 694         KKASSERT(*segp >= 1 && *segp <= nsegments);
 695         seg = *segp;
 696         sg = &segments[seg - 1];
 697
 698         vaddr = (vm_offset_t)buf;
 699         nextpaddr = *lastpaddrp;
 700         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 701
 702         /* force at least one segment */
 703         do {
 704                 bus_size_t size;
 705
 706                 /*
 707                  * Per-page main loop
 708                  */
 709                 paddr = _bus_dma_extract(pmap, vaddr);
 710                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 711                 if (size > buflen)
 712                         size = buflen;
 713                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 714                         /*
 715                          * note: this paddr has the same in-page offset
 716                          * as vaddr and thus the paddr above, so the
 717                          * size does not have to be recalculated
 718                          */
 719                         paddr = add_bounce_page(dmat, map, vaddr, size);
 720                 }
 721
 722                 /*
 723                  * Fill in the bus_dma_segment
 724                  */
 725                 if (first) {
 726                         sg->ds_addr = paddr;
 727                         sg->ds_len = size;
 728                         first = 0;
 729                 } else if (paddr == nextpaddr) {
 730                         sg->ds_len += size;
 731                 } else {
 732                         sg++;
 733                         seg++;
 734                         if (seg > nsegments)
 735                                 break;
 736                         sg->ds_addr = paddr;
 737                         sg->ds_len = size;
 738                 }
 739                 nextpaddr = paddr + size;
 740
 741                 /*
 742                  * Handle maxsegsz and boundary issues with a nested loop
 743                  */
 744                 for (;;) {
 745                         bus_size_t tmpsize;
 746
 747                         /*
 748                          * Limit to the boundary and maximum segment size
 749                          */
 750                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 751                                 tmpsize = dmat->boundary -
 752                                           (sg->ds_addr & ~bmask);
 753                                 if (tmpsize > dmat->maxsegsz)
 754                                         tmpsize = dmat->maxsegsz;
 755                                 KKASSERT(tmpsize < sg->ds_len);
 756                         } else if (sg->ds_len > dmat->maxsegsz) {
 757                                 tmpsize = dmat->maxsegsz;
 758                         } else {
 759                                 break;
 760                         }
 761
 762                         /*
 763                          * Futz, split the data into a new segment.
 764                          */
 765                         if (seg >= nsegments)
 766                                 goto fail;
 767                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 768                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 769                         sg[0].ds_len = tmpsize;
 770                         sg++;
 771                         seg++;
 772                 }
 773
 774                 /*
 775                  * Adjust for loop
 776                  */
 777                 buflen -= size;
 778                 vaddr += size;
 779         } while (buflen > 0);
 780 fail:
 781         if (buflen != 0)
 782                 error = EFBIG;
 783
 784         *segp = seg;
 785         *lastpaddrp = nextpaddr;
 786
 787 free_bounce:
 788         if (error && (dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 789             map != &nobounce_dmamap) {
 790                 _bus_dmamap_unload(dmat, map);
 791                 return_bounce_pages(dmat, map);
 792         }
 793         return error;
 794 }
 795
 796 /*
 797  * Map the buffer buf into bus space using the dmamap map.
 798  */
 799 int
 800 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 801                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 802                 void *callback_arg, int flags)
 803 {
 804         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 805         bus_dma_segment_t *segments;
 806         vm_paddr_t lastaddr = 0;
 807         int error, nsegs = 1;
 808
 809         if (map != NULL) {
 810                 /*
 811                  * XXX
 812                  * Follow old semantics.  Once all of the callers are fixed,
 813                  * we should get rid of these internal flag "adjustment".
 814                  */
 815                 flags &= ~BUS_DMA_NOWAIT;
 816                 flags |= BUS_DMA_WAITOK;
 817
 818                 map->callback = callback;
 819                 map->callback_arg = callback_arg;
 820         }
 821
 822         segments = bus_dma_tag_lock(dmat, cache_segments);
 823         error = _bus_dmamap_load_buffer(dmat, map, buf, buflen,
 824                         segments, dmat->nsegments,
 825                         NULL, flags, &lastaddr, &nsegs, 1);
 826         if (error == EINPROGRESS) {
 827                 bus_dma_tag_unlock(dmat);
 828                 return error;
 829         }
 830         callback(callback_arg, segments, nsegs, error);
 831         bus_dma_tag_unlock(dmat);
 832         return 0;
 833 }
 834
 835 /*
 836  * Like _bus_dmamap_load(), but for mbufs.
 837  */
 838 int
 839 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 840                      struct mbuf *m0,
 841                      bus_dmamap_callback2_t *callback, void *callback_arg,
 842                      int flags)
 843 {
 844         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 845         bus_dma_segment_t *segments;
 846         int nsegs, error;
 847
 848         /*
 849          * XXX
 850          * Follow old semantics.  Once all of the callers are fixed,
 851          * we should get rid of these internal flag "adjustment".
 852          */
 853         flags &= ~BUS_DMA_WAITOK;
 854         flags |= BUS_DMA_NOWAIT;
 855
 856         segments = bus_dma_tag_lock(dmat, cache_segments);
 857         error = bus_dmamap_load_mbuf_segment(dmat, map, m0,
 858                         segments, dmat->nsegments, &nsegs, flags);
 859         if (error) {
 860                 /* force "no valid mappings" in callback */
 861                 callback(callback_arg, segments, 0,
 862                          0, error);
 863         } else {
 864                 callback(callback_arg, segments, nsegs,
 865                          m0->m_pkthdr.len, error);
 866         }
 867         bus_dma_tag_unlock(dmat);
 868         return error;
 869 }
 870
 871 int
 872 bus_dmamap_load_mbuf_segment(bus_dma_tag_t dmat, bus_dmamap_t map,
 873                              struct mbuf *m0,
 874                              bus_dma_segment_t *segs, int maxsegs,
 875                              int *nsegs, int flags)
 876 {
 877         int error;
 878
 879         M_ASSERTPKTHDR(m0);
 880
 881         KASSERT(maxsegs >= 1, ("invalid maxsegs %d\n", maxsegs));
 882         KASSERT(maxsegs <= dmat->nsegments,
 883                 ("%d too many segments, dmat only support %d segments\n",
 884                  maxsegs, dmat->nsegments));
 885         KASSERT(flags & BUS_DMA_NOWAIT,
 886                 ("only BUS_DMA_NOWAIT is supported\n"));
 887
 888         if (m0->m_pkthdr.len <= dmat->maxsize) {
 889                 int first = 1;
 890                 vm_paddr_t lastaddr = 0;
 891                 struct mbuf *m;
 892
 893                 *nsegs = 1;
 894                 error = 0;
 895                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 896                         if (m->m_len == 0)
 897                                 continue;
 898
 899                         error = _bus_dmamap_load_buffer(dmat, map,
 900                                         m->m_data, m->m_len,
 901                                         segs, maxsegs,
 902                                         NULL, flags, &lastaddr,
 903                                         nsegs, first);
 904                         if (error == ENOMEM && !first) {
 905                                 /*
 906                                  * Out of bounce pages due to too many
 907                                  * fragments in the mbuf chain; return
 908                                  * EFBIG instead.
 909                                  */
 910                                 error = EFBIG;
 911                         }
 912                         first = 0;
 913                 }
 914 #ifdef INVARIANTS
 915                 if (!error)
 916                         KKASSERT(*nsegs <= maxsegs && *nsegs >= 1);
 917 #endif
 918         } else {
 919                 *nsegs = 0;
 920                 error = EINVAL;
 921         }
 922         KKASSERT(error != EINPROGRESS);
 923         return error;
 924 }
 925
 926 /*
 927  * Like _bus_dmamap_load(), but for uios.
 928  */
 929 int
 930 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 931                     struct uio *uio,
 932                     bus_dmamap_callback2_t *callback, void *callback_arg,
 933                     int flags)
 934 {
 935         vm_paddr_t lastaddr;
 936         int nsegs, error, first, i;
 937         bus_size_t resid;
 938         struct iovec *iov;
 939         pmap_t pmap;
 940         bus_dma_segment_t cache_segments[BUS_DMA_CACHE_SEGMENTS];
 941         bus_dma_segment_t *segments;
 942         bus_dma_segment_t *segs;
 943         int nsegs_left;
 944
 945         if (dmat->nsegments <= BUS_DMA_CACHE_SEGMENTS)
 946                 segments = cache_segments;
 947         else
 948                 segments = kmalloc(sizeof(bus_dma_segment_t) * dmat->nsegments,
 949                                    M_DEVBUF, M_WAITOK | M_ZERO);
 950
 951         /*
 952          * XXX
 953          * Follow old semantics.  Once all of the callers are fixed,
 954          * we should get rid of these internal flag "adjustment".
 955          */
 956         flags &= ~BUS_DMA_WAITOK;
 957         flags |= BUS_DMA_NOWAIT;
 958
 959         resid = (bus_size_t)uio->uio_resid;
 960         iov = uio->uio_iov;
 961
 962         segs = segments;
 963         nsegs_left = dmat->nsegments;
 964
 965         if (uio->uio_segflg == UIO_USERSPACE) {
 966                 struct thread *td;
 967
 968                 td = uio->uio_td;
 969                 KASSERT(td != NULL && td->td_proc != NULL,
 970                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 971                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 972         } else {
 973                 pmap = NULL;
 974         }
 975
 976         error = 0;
 977         nsegs = 1;
 978         first = 1;
 979         lastaddr = 0;
 980         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 981                 /*
 982                  * Now at the first iovec to load.  Load each iovec
 983                  * until we have exhausted the residual count.
 984                  */
 985                 bus_size_t minlen =
 986                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 987                 caddr_t addr = (caddr_t) iov[i].iov_base;
 988
 989                 error = _bus_dmamap_load_buffer(dmat, map, addr, minlen,
 990                                 segs, nsegs_left,
 991                                 pmap, flags, &lastaddr, &nsegs, first);
 992                 first = 0;
 993
 994                 resid -= minlen;
 995                 if (error == 0) {
 996                         nsegs_left -= nsegs;
 997                         segs += nsegs;
 998                 }
 999         }
1000
1001         /*
1002          * Minimum one DMA segment, even if 0-length buffer.
1003          */
1004         if (nsegs_left == dmat->nsegments)
1005                 --nsegs_left;
1006
1007         if (error) {
1008                 /* force "no valid mappings" in callback */
1009                 callback(callback_arg, segments, 0,
1010                          0, error);
1011         } else {
1012                 callback(callback_arg, segments, dmat->nsegments - nsegs_left,
1013                          (bus_size_t)uio->uio_resid, error);
1014         }
1015         if (dmat->nsegments > BUS_DMA_CACHE_SEGMENTS)
1016                 kfree(segments, M_DEVBUF);
1017         return error;
1018 }
1019
1020 /*
1021  * Release the mapping held by map.
1022  */
1023 void
1024 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
1025 {
1026         struct bounce_page *bpage;
1027
1028         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1029                 STAILQ_REMOVE_HEAD(&map->bpages, links);
1030                 free_bounce_page(dmat, bpage);
1031         }
1032 }
1033
1034 void
1035 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
1036 {
1037         struct bounce_page *bpage;
1038
1039         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
1040                 /*
1041                  * Handle data bouncing.  We might also
1042                  * want to add support for invalidating
1043                  * the caches on broken hardware
1044                  */
1045                 switch (op) {
1046                 case BUS_DMASYNC_PREWRITE:
1047                         while (bpage != NULL) {
1048                                 bcopy((void *)bpage->datavaddr,
1049                                       (void *)bpage->vaddr,
1050                                       bpage->datacount);
1051                                 bpage = STAILQ_NEXT(bpage, links);
1052                         }
1053                         dmat->bounce_zone->total_bounced++;
1054                         break;
1055
1056                 case BUS_DMASYNC_POSTREAD:
1057                         while (bpage != NULL) {
1058                                 bcopy((void *)bpage->vaddr,
1059                                       (void *)bpage->datavaddr,
1060                                       bpage->datacount);
1061                                 bpage = STAILQ_NEXT(bpage, links);
1062                         }
1063                         dmat->bounce_zone->total_bounced++;
1064                         break;
1065
1066                 case BUS_DMASYNC_PREREAD:
1067                 case BUS_DMASYNC_POSTWRITE:
1068                         /* No-ops */
1069                         break;
1070                 }
1071         }
1072 }
1073
1074 static int
1075 alloc_bounce_zone(bus_dma_tag_t dmat)
1076 {
1077         struct bounce_zone *bz, *new_bz;
1078
1079         KASSERT(dmat->bounce_zone == NULL,
1080                 ("bounce zone was already assigned\n"));
1081
1082         new_bz = kmalloc(sizeof(*new_bz), M_DEVBUF, M_INTWAIT | M_ZERO);
1083
1084         lwkt_gettoken(&bounce_zone_tok);
1085
1086         /* Check to see if we already have a suitable zone */
1087         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
1088                 if (dmat->alignment <= bz->alignment &&
1089                     dmat->lowaddr >= bz->lowaddr) {
1090                         lwkt_reltoken(&bounce_zone_tok);
1091
1092                         dmat->bounce_zone = bz;
1093                         kfree(new_bz, M_DEVBUF);
1094                         return 0;
1095                 }
1096         }
1097         bz = new_bz;
1098
1099 #ifdef SMP
1100         spin_init(&bz->spin);
1101 #endif
1102         STAILQ_INIT(&bz->bounce_page_list);
1103         STAILQ_INIT(&bz->bounce_map_waitinglist);
1104         bz->free_bpages = 0;
1105         bz->reserved_bpages = 0;
1106         bz->active_bpages = 0;
1107         bz->lowaddr = dmat->lowaddr;
1108         bz->alignment = round_page(dmat->alignment);
1109         ksnprintf(bz->zoneid, 8, "zone%d", busdma_zonecount);
1110         busdma_zonecount++;
1111         ksnprintf(bz->lowaddrid, 18, "%#jx", (uintmax_t)bz->lowaddr);
1112         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
1113
1114         lwkt_reltoken(&bounce_zone_tok);
1115
1116         dmat->bounce_zone = bz;
1117
1118         sysctl_ctx_init(&bz->sysctl_ctx);
1119         bz->sysctl_tree = SYSCTL_ADD_NODE(&bz->sysctl_ctx,
1120             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
1121             CTLFLAG_RD, 0, "");
1122         if (bz->sysctl_tree == NULL) {
1123                 sysctl_ctx_free(&bz->sysctl_ctx);
1124                 return 0;       /* XXX error code? */
1125         }
1126
1127         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1128             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1129             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
1130             "Total bounce pages");
1131         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1132             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1133             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
1134             "Free bounce pages");
1135         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1136             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1137             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
1138             "Reserved bounce pages");
1139         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1140             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1141             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
1142             "Active bounce pages");
1143         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1144             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1145             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
1146             "Total bounce requests");
1147         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1148             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1149             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
1150             "Total bounce requests that were deferred");
1151         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1152             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1153             "reserve_failed", CTLFLAG_RD, &bz->reserve_failed, 0,
1154             "Total bounce page reservations that were failed");
1155         SYSCTL_ADD_STRING(&bz->sysctl_ctx,
1156             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1157             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
1158         SYSCTL_ADD_INT(&bz->sysctl_ctx,
1159             SYSCTL_CHILDREN(bz->sysctl_tree), OID_AUTO,
1160             "alignment", CTLFLAG_RD, &bz->alignment, 0, "");
1161
1162         return 0;
1163 }
1164
1165 static int
1166 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages, int flags)
1167 {
1168         struct bounce_zone *bz = dmat->bounce_zone;
1169         int count = 0, mflags;
1170
1171         if (flags & BUS_DMA_NOWAIT)
1172                 mflags = M_NOWAIT;
1173         else
1174                 mflags = M_WAITOK;
1175
1176         while (numpages > 0) {
1177                 struct bounce_page *bpage;
1178
1179                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
1180
1181                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
1182                                                          mflags, 0ul,
1183                                                          bz->lowaddr,
1184                                                          bz->alignment, 0);
1185                 if (bpage->vaddr == 0) {
1186                         kfree(bpage, M_DEVBUF);
1187                         break;
1188                 }
1189                 bpage->busaddr = pmap_kextract(bpage->vaddr);
1190
1191                 BZ_LOCK(bz);
1192                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
1193                 total_bounce_pages++;
1194                 bz->total_bpages++;
1195                 bz->free_bpages++;
1196                 BZ_UNLOCK(bz);
1197
1198                 count++;
1199                 numpages--;
1200         }
1201         return count;
1202 }
1203
1204 /* Assume caller holds bounce zone spinlock */
1205 static int
1206 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
1207 {
1208         struct bounce_zone *bz = dmat->bounce_zone;
1209         int pages;
1210
1211         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
1212         if (!commit && map->pagesneeded > (map->pagesreserved + pages)) {
1213                 bz->reserve_failed++;
1214                 return (map->pagesneeded - (map->pagesreserved + pages));
1215         }
1216
1217         bz->free_bpages -= pages;
1218
1219         bz->reserved_bpages += pages;
1220         KKASSERT(bz->reserved_bpages <= bz->total_bpages);
1221
1222         map->pagesreserved += pages;
1223         pages = map->pagesneeded - map->pagesreserved;
1224
1225         return pages;
1226 }
1227
1228 static void
1229 return_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
1230 {
1231         struct bounce_zone *bz = dmat->bounce_zone;
1232         int reserved = map->pagesreserved;
1233         bus_dmamap_t wait_map;
1234
1235         map->pagesreserved = 0;
1236         map->pagesneeded = 0;
1237
1238         if (reserved == 0)
1239                 return;
1240
1241         BZ_LOCK(bz);
1242
1243         bz->free_bpages += reserved;
1244         KKASSERT(bz->free_bpages <= bz->total_bpages);
1245
1246         KKASSERT(bz->reserved_bpages >= reserved);
1247         bz->reserved_bpages -= reserved;
1248
1249         wait_map = get_map_waiting(dmat);
1250
1251         BZ_UNLOCK(bz);
1252
1253         if (wait_map != NULL)
1254                 add_map_callback(map);
1255 }
1256
1257 static bus_addr_t
1258 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
1259                 bus_size_t size)
1260 {
1261         struct bounce_zone *bz = dmat->bounce_zone;
1262         struct bounce_page *bpage;
1263
1264         KASSERT(map->pagesneeded > 0, ("map doesn't need any pages"));
1265         map->pagesneeded--;
1266
1267         KASSERT(map->pagesreserved > 0, ("map doesn't reserve any pages"));
1268         map->pagesreserved--;
1269
1270         BZ_LOCK(bz);
1271
1272         bpage = STAILQ_FIRST(&bz->bounce_page_list);
1273         KASSERT(bpage != NULL, ("free page list is empty"));
1274         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
1275
1276         KKASSERT(bz->reserved_bpages > 0);
1277         bz->reserved_bpages--;
1278
1279         bz->active_bpages++;
1280         KKASSERT(bz->active_bpages <= bz->total_bpages);
1281
1282         BZ_UNLOCK(bz);
1283
1284         bpage->datavaddr = vaddr;
1285         bpage->datacount = size;
1286         STAILQ_INSERT_TAIL(&map->bpages, bpage, links);
1287         return bpage->busaddr;
1288 }
1289
1290 static void
1291 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
1292 {
1293         struct bounce_zone *bz = dmat->bounce_zone;
1294         bus_dmamap_t map;
1295
1296         bpage->datavaddr = 0;
1297         bpage->datacount = 0;
1298
1299         BZ_LOCK(bz);
1300
1301         STAILQ_INSERT_HEAD(&bz->bounce_page_list, bpage, links);
1302
1303         bz->free_bpages++;
1304         KKASSERT(bz->free_bpages <= bz->total_bpages);
1305
1306         KKASSERT(bz->active_bpages > 0);
1307         bz->active_bpages--;
1308
1309         map = get_map_waiting(dmat);
1310
1311         BZ_UNLOCK(bz);
1312
1313         if (map != NULL)
1314                 add_map_callback(map);
1315 }
1316
1317 /* Assume caller holds bounce zone spinlock */
1318 static bus_dmamap_t
1319 get_map_waiting(bus_dma_tag_t dmat)
1320 {
1321         struct bounce_zone *bz = dmat->bounce_zone;
1322         bus_dmamap_t map;
1323
1324         map = STAILQ_FIRST(&bz->bounce_map_waitinglist);
1325         if (map != NULL) {
1326                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
1327                         STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
1328                         bz->total_deferred++;
1329                 } else {
1330                         map = NULL;
1331                 }
1332         }
1333         return map;
1334 }
1335
1336 static void
1337 add_map_callback(bus_dmamap_t map)
1338 {
1339         spin_lock(&bounce_map_list_spin);
1340         STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
1341         busdma_swi_pending = 1;
1342         setsoftvm();
1343         spin_unlock(&bounce_map_list_spin);
1344 }
1345
1346 void
1347 busdma_swi(void)
1348 {
1349         bus_dmamap_t map;
1350
1351         spin_lock(&bounce_map_list_spin);
1352         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
1353                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
1354                 spin_unlock(&bounce_map_list_spin);
1355                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
1356                                 map->callback, map->callback_arg, /*flags*/0);
1357                 spin_lock(&bounce_map_list_spin);
1358         }
1359         spin_unlock(&bounce_map_list_spin);
1360 }