sys/platform/pc32/i386/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 1.16.2.2 2003/01/23 00:55:27 scottl Exp $
  27  * $DragonFly: src/sys/platform/pc32/i386/busdma_machdep.c,v 1.18 2006/12/23 00:27:03 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/thread2.h>
  36 #include <sys/bus_dma.h>
  37
  38 #include <vm/vm.h>
  39 #include <vm/vm_page.h>
  40
  41 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  42 #include <sys/proc.h>
  43 #include <sys/lock.h>
  44 #include <vm/vm_map.h>
  45
  46 #include <machine/md_var.h>
  47
  48 #define MAX_BPAGES 128
  49
  50 struct bus_dma_tag {
  51         bus_dma_tag_t     parent;
  52         bus_size_t        alignment;
  53         bus_size_t        boundary;
  54         bus_addr_t        lowaddr;
  55         bus_addr_t        highaddr;
  56         bus_dma_filter_t *filter;
  57         void             *filterarg;
  58         bus_size_t        maxsize;
  59         u_int             nsegments;
  60         bus_size_t        maxsegsz;
  61         int               flags;
  62         int               ref_count;
  63         int               map_count;
  64         bus_dma_segment_t *segments;
  65 };
  66
  67 struct bounce_page {
  68         vm_offset_t     vaddr;          /* kva of bounce buffer */
  69         bus_addr_t      busaddr;        /* Physical address */
  70         vm_offset_t     datavaddr;      /* kva of client data */
  71         bus_size_t      datacount;      /* client data count */
  72         STAILQ_ENTRY(bounce_page) links;
  73 };
  74
  75 int busdma_swi_pending;
  76
  77 static STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  78 static int free_bpages;
  79 static int reserved_bpages;
  80 static int active_bpages;
  81 static int total_bpages;
  82 static bus_addr_t bounce_lowaddr = BUS_SPACE_MAXADDR;
  83
  84 struct bus_dmamap {
  85         struct bp_list         bpages;
  86         int                    pagesneeded;
  87         int                    pagesreserved;
  88         bus_dma_tag_t          dmat;
  89         void                  *buf;             /* unmapped buffer pointer */
  90         bus_size_t             buflen;          /* unmapped buffer length */
  91         bus_dmamap_callback_t *callback;
  92         void                  *callback_arg;
  93         STAILQ_ENTRY(bus_dmamap) links;
  94 };
  95
  96 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
  97 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
  98 static struct bus_dmamap nobounce_dmamap;
  99
 100 static int alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages);
 101 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map);
 102 static bus_addr_t add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map,
 103                                    vm_offset_t vaddr, bus_size_t size);
 104 static void free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage);
 105 static __inline int run_filter(bus_dma_tag_t dmat, bus_addr_t paddr);
 106
 107 static __inline int
 108 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 109 {
 110         int retval;
 111
 112         retval = 0;
 113         do {
 114                 if (paddr > dmat->lowaddr
 115                  && paddr <= dmat->highaddr
 116                  && (dmat->filter == NULL
 117                   || (*dmat->filter)(dmat->filterarg, paddr) != 0))
 118                         retval = 1;
 119
 120                 dmat = dmat->parent;
 121         } while (retval == 0 && dmat != NULL);
 122         return (retval);
 123 }
 124
 125 #define BUS_DMA_MIN_ALLOC_COMP BUS_DMA_BUS4
 126 /*
 127  * Allocate a device specific dma_tag.
 128  */
 129 int
 130 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 131                    bus_size_t boundary, bus_addr_t lowaddr,
 132                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 133                    void *filterarg, bus_size_t maxsize, int nsegments,
 134                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 135 {
 136         bus_dma_tag_t newtag;
 137         int error = 0;
 138
 139         /* Return a NULL tag on failure */
 140         *dmat = NULL;
 141
 142         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT);
 143
 144         newtag->parent = parent;
 145         newtag->alignment = alignment;
 146         newtag->boundary = boundary;
 147         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 148         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 149         newtag->filter = filter;
 150         newtag->filterarg = filterarg;
 151         newtag->maxsize = maxsize;
 152         newtag->nsegments = nsegments;
 153         newtag->maxsegsz = maxsegsz;
 154         newtag->flags = flags;
 155         newtag->ref_count = 1; /* Count ourself */
 156         newtag->map_count = 0;
 157         newtag->segments = NULL;
 158
 159         /* Take into account any restrictions imposed by our parent tag */
 160         if (parent != NULL) {
 161                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 162                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 163                 /*
 164                  * XXX Not really correct??? Probably need to honor boundary
 165                  *     all the way up the inheritence chain.
 166                  */
 167                 newtag->boundary = MAX(parent->boundary, newtag->boundary);
 168                 if (newtag->filter == NULL) {
 169                         /*
 170                          * Short circuit looking at our parent directly
 171                          * since we have encapsulated all of its information
 172                          */
 173                         newtag->filter = parent->filter;
 174                         newtag->filterarg = parent->filterarg;
 175                         newtag->parent = parent->parent;
 176                 }
 177                 if (newtag->parent != NULL) {
 178                         parent->ref_count++;
 179                 }
 180         }
 181
 182         if (newtag->lowaddr < ptoa(Maxmem) &&
 183             (flags & BUS_DMA_ALLOCNOW) != 0) {
 184                 /* Must bounce */
 185
 186                 if (lowaddr > bounce_lowaddr) {
 187                         /*
 188                          * Go through the pool and kill any pages
 189                          * that don't reside below lowaddr.
 190                          */
 191                         panic("bus_dma_tag_create: page reallocation "
 192                               "not implemented");
 193                 }
 194                 if (ptoa(total_bpages) < maxsize) {
 195                         int pages;
 196
 197                         pages = atop(maxsize) - total_bpages;
 198
 199                         /* Add pages to our bounce pool */
 200                         if (alloc_bounce_pages(newtag, pages) < pages)
 201                                 error = ENOMEM;
 202                 }
 203                 /* Performed initial allocation */
 204                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 205         }
 206
 207         if (error != 0) {
 208                 kfree(newtag, M_DEVBUF);
 209         } else {
 210                 *dmat = newtag;
 211         }
 212         return (error);
 213 }
 214
 215 int
 216 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 217 {
 218         if (dmat != NULL) {
 219
 220                 if (dmat->map_count != 0)
 221                         return (EBUSY);
 222
 223                 while (dmat != NULL) {
 224                         bus_dma_tag_t parent;
 225
 226                         parent = dmat->parent;
 227                         dmat->ref_count--;
 228                         if (dmat->ref_count == 0) {
 229                                 if (dmat->segments != NULL)
 230                                         kfree(dmat->segments, M_DEVBUF);
 231                                 kfree(dmat, M_DEVBUF);
 232                                 /*
 233                                  * Last reference count, so
 234                                  * release our reference
 235                                  * count on our parent.
 236                                  */
 237                                 dmat = parent;
 238                         } else
 239                                 dmat = NULL;
 240                 }
 241         }
 242         return (0);
 243 }
 244
 245 /*
 246  * Allocate a handle for mapping from kva/uva/physical
 247  * address space into bus device space.
 248  */
 249 int
 250 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 251 {
 252         int error;
 253
 254         error = 0;
 255
 256         if (dmat->segments == NULL) {
 257                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 258                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 259                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 260         }
 261
 262         if (dmat->lowaddr < ptoa(Maxmem)) {
 263                 /* Must bounce */
 264                 int maxpages;
 265
 266                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT);
 267                 if (*mapp == NULL) {
 268                         return (ENOMEM);
 269                 } else {
 270                         /* Initialize the new map */
 271                         bzero(*mapp, sizeof(**mapp));
 272                         STAILQ_INIT(&((*mapp)->bpages));
 273                 }
 274                 /*
 275                  * Attempt to add pages to our pool on a per-instance
 276                  * basis up to a sane limit.
 277                  */
 278                 maxpages = MIN(MAX_BPAGES, Maxmem - atop(dmat->lowaddr));
 279                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 280                  || (dmat->map_count > 0
 281                   && total_bpages < maxpages)) {
 282                         int pages;
 283
 284                         if (dmat->lowaddr > bounce_lowaddr) {
 285                                 /*
 286                                  * Go through the pool and kill any pages
 287                                  * that don't reside below lowaddr.
 288                                  */
 289                                 panic("bus_dmamap_create: page reallocation "
 290                                       "not implemented");
 291                         }
 292                         pages = atop(dmat->maxsize);
 293                         pages = MIN(maxpages - total_bpages, pages);
 294                         error = alloc_bounce_pages(dmat, pages);
 295
 296                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 297                                 if (error == 0)
 298                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 299                         } else {
 300                                 error = 0;
 301                         }
 302                 }
 303         } else {
 304                 *mapp = NULL;
 305         }
 306         if (error == 0)
 307                 dmat->map_count++;
 308         return (error);
 309 }
 310
 311 /*
 312  * Destroy a handle for mapping from kva/uva/physical
 313  * address space into bus device space.
 314  */
 315 int
 316 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 317 {
 318         if (map != NULL) {
 319                 if (STAILQ_FIRST(&map->bpages) != NULL)
 320                         return (EBUSY);
 321                 kfree(map, M_DEVBUF);
 322         }
 323         dmat->map_count--;
 324         return (0);
 325 }
 326
 327
 328 /*
 329  * Allocate a piece of memory that can be efficiently mapped into
 330  * bus device space based on the constraints lited in the dma tag.
 331  *
 332  * mapp is degenerate.  By definition this allocation should not require
 333  * bounce buffers so do not allocate a dma map.
 334  */
 335 int
 336 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 337                  bus_dmamap_t *mapp)
 338 {
 339         int mflags;
 340         /* If we succeed, no mapping/bouncing will be required */
 341         *mapp = NULL;
 342
 343         if (dmat->segments == NULL) {
 344                 KKASSERT(dmat->nsegments < 16384);
 345                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 346                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 347         }
 348
 349         if (flags & BUS_DMA_NOWAIT)
 350                 mflags = M_NOWAIT;
 351         else
 352                 mflags = M_WAITOK;
 353         if (flags & BUS_DMA_ZERO)
 354                 mflags |= M_ZERO;
 355
 356         if ((dmat->maxsize <= PAGE_SIZE) &&
 357             dmat->lowaddr >= ptoa(Maxmem)) {
 358                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 359                 /*
 360                  * XXX Check whether the allocation crossed a page boundary
 361                  * and retry with power-of-2 alignment in that case.
 362                  */
 363                 if ((((intptr_t)*vaddr) & PAGE_MASK) !=
 364                     (((intptr_t)*vaddr + dmat->maxsize) & PAGE_MASK)) {
 365                         size_t size;
 366                         kfree(*vaddr, M_DEVBUF);
 367                         /* XXX check for overflow? */
 368                         for (size = 1; size <= dmat->maxsize; size <<= 1)
 369                                 ;
 370                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 371                 }
 372         } else {
 373                 /*
 374                  * XXX Use Contigmalloc until it is merged into this facility
 375                  *     and handles multi-seg allocations.  Nobody is doing
 376                  *     multi-seg allocations yet though.
 377                  */
 378                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 379                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 380                     dmat->boundary);
 381         }
 382         if (*vaddr == NULL)
 383                 return (ENOMEM);
 384         return (0);
 385 }
 386
 387 /*
 388  * Free a piece of memory and it's allociated dmamap, that was allocated
 389  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 390  */
 391 void
 392 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 393 {
 394         /*
 395          * dmamem does not need to be bounced, so the map should be
 396          * NULL
 397          */
 398         if (map != NULL)
 399                 panic("bus_dmamem_free: Invalid map freed\n");
 400         if ((dmat->maxsize <= PAGE_SIZE) &&
 401             dmat->lowaddr >= ptoa(Maxmem))
 402                 kfree(vaddr, M_DEVBUF);
 403         else
 404                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 405 }
 406
 407 #define BUS_DMAMAP_NSEGS ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
 408
 409 /*
 410  * Map the buffer buf into bus space using the dmamap map.
 411  */
 412 int
 413 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 414                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 415                 void *callback_arg, int flags)
 416 {
 417         vm_offset_t             vaddr;
 418         vm_paddr_t              paddr;
 419         bus_dma_segment_t      *sg;
 420         int                     seg;
 421         int                     error;
 422         vm_paddr_t              nextpaddr;
 423
 424         if (map == NULL)
 425                 map = &nobounce_dmamap;
 426
 427         error = 0;
 428         /*
 429          * If we are being called during a callback, pagesneeded will
 430          * be non-zero, so we can avoid doing the work twice.
 431          */
 432         if (dmat->lowaddr < ptoa(Maxmem) &&
 433             map->pagesneeded == 0) {
 434                 vm_offset_t     vendaddr;
 435
 436                 /*
 437                  * Count the number of bounce pages
 438                  * needed in order to complete this transfer
 439                  */
 440                 vaddr = trunc_page((vm_offset_t)buf);
 441                 vendaddr = (vm_offset_t)buf + buflen;
 442
 443                 while (vaddr < vendaddr) {
 444                         paddr = pmap_kextract(vaddr);
 445                         if (run_filter(dmat, paddr) != 0) {
 446
 447                                 map->pagesneeded++;
 448                         }
 449                         vaddr += PAGE_SIZE;
 450                 }
 451         }
 452
 453         /* Reserve Necessary Bounce Pages */
 454         if (map->pagesneeded != 0) {
 455                 crit_enter();
 456                 if (reserve_bounce_pages(dmat, map) != 0) {
 457
 458                         /* Queue us for resources */
 459                         map->dmat = dmat;
 460                         map->buf = buf;
 461                         map->buflen = buflen;
 462                         map->callback = callback;
 463                         map->callback_arg = callback_arg;
 464
 465                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 466                         crit_exit();
 467
 468                         return (EINPROGRESS);
 469                 }
 470                 crit_exit();
 471         }
 472
 473         vaddr = (vm_offset_t)buf;
 474         sg = dmat->segments;
 475         seg = 1;
 476         sg->ds_len = 0;
 477
 478         nextpaddr = 0;
 479         do {
 480                 bus_size_t      size;
 481
 482                 paddr = pmap_kextract(vaddr);
 483                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 484                 if (size > buflen)
 485                         size = buflen;
 486
 487                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 488                         paddr = add_bounce_page(dmat, map, vaddr, size);
 489                 }
 490
 491                 if (sg->ds_len == 0) {
 492                         sg->ds_addr = paddr;
 493                         sg->ds_len = size;
 494                 } else if (paddr == nextpaddr) {
 495                         sg->ds_len += size;
 496                 } else {
 497                         /* Go to the next segment */
 498                         sg++;
 499                         seg++;
 500                         if (seg > dmat->nsegments)
 501                                 break;
 502                         sg->ds_addr = paddr;
 503                         sg->ds_len = size;
 504                 }
 505                 vaddr += size;
 506                 nextpaddr = paddr + size;
 507                 buflen -= size;
 508         } while (buflen > 0);
 509
 510         if (buflen != 0) {
 511                 kprintf("bus_dmamap_load: Too many segs! buf_len = 0x%lx\n",
 512                        (u_long)buflen);
 513                 error = EFBIG;
 514         }
 515
 516         (*callback)(callback_arg, dmat->segments, seg, error);
 517
 518         return (0);
 519 }
 520
 521 /*
 522  * Utility function to load a linear buffer.  lastaddrp holds state
 523  * between invocations (for multiple-buffer loads).  segp contains
 524  * the starting segment on entrace, and the ending segment on exit.
 525  * first indicates if this is the first invocation of this function.
 526  */
 527 static int
 528 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 529                         void *buf, bus_size_t buflen,
 530                         struct thread *td,
 531                         int flags,
 532                         vm_offset_t *lastaddrp,
 533                         int *segp,
 534                         int first)
 535 {
 536         bus_dma_segment_t *segs;
 537         bus_size_t sgsize;
 538         bus_addr_t curaddr, lastaddr, baddr, bmask;
 539         vm_offset_t vaddr = (vm_offset_t)buf;
 540         int seg;
 541         pmap_t pmap;
 542
 543         if (td->td_proc != NULL)
 544                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 545         else
 546                 pmap = NULL;
 547
 548         segs = dmat->segments;
 549         lastaddr = *lastaddrp;
 550         bmask  = ~(dmat->boundary - 1);
 551
 552         for (seg = *segp; buflen > 0 ; ) {
 553                 /*
 554                  * Get the physical address for this segment.
 555                  */
 556                 if (pmap)
 557                         curaddr = pmap_extract(pmap, vaddr);
 558                 else
 559                         curaddr = pmap_kextract(vaddr);
 560
 561                 /*
 562                  * Compute the segment size, and adjust counts.
 563                  */
 564                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
 565                 if (buflen < sgsize)
 566                         sgsize = buflen;
 567
 568                 /*
 569                  * Make sure we don't cross any boundaries.
 570                  */
 571                 if (dmat->boundary > 0) {
 572                         baddr = (curaddr + dmat->boundary) & bmask;
 573                         if (sgsize > (baddr - curaddr))
 574                                 sgsize = (baddr - curaddr);
 575                 }
 576
 577                 /*
 578                  * Insert chunk into a segment, coalescing with
 579                  * previous segment if possible.
 580                  */
 581                 if (first) {
 582                         segs[seg].ds_addr = curaddr;
 583                         segs[seg].ds_len = sgsize;
 584                         first = 0;
 585                 } else {
 586                         if (curaddr == lastaddr &&
 587                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 588                             (dmat->boundary == 0 ||
 589                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 590                                 segs[seg].ds_len += sgsize;
 591                         else {
 592                                 if (++seg >= dmat->nsegments)
 593                                         break;
 594                                 segs[seg].ds_addr = curaddr;
 595                                 segs[seg].ds_len = sgsize;
 596                         }
 597                 }
 598
 599                 lastaddr = curaddr + sgsize;
 600                 vaddr += sgsize;
 601                 buflen -= sgsize;
 602         }
 603
 604         *segp = seg;
 605         *lastaddrp = lastaddr;
 606
 607         /*
 608          * Did we fit?
 609          */
 610         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 611 }
 612
 613 /*
 614  * Like _bus_dmamap_load(), but for mbufs.
 615  */
 616 int
 617 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 618                      struct mbuf *m0,
 619                      bus_dmamap_callback2_t *callback, void *callback_arg,
 620                      int flags)
 621 {
 622         int nsegs, error;
 623
 624         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 625                 ("bus_dmamap_load_mbuf: No support for bounce pages!"));
 626         KASSERT(m0->m_flags & M_PKTHDR,
 627                 ("bus_dmamap_load_mbuf: no packet header"));
 628
 629         nsegs = 0;
 630         error = 0;
 631         if (m0->m_pkthdr.len <= dmat->maxsize) {
 632                 int first = 1;
 633                 vm_offset_t lastaddr = 0;
 634                 struct mbuf *m;
 635
 636                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 637                         if ( m->m_len == 0 )
 638                                 continue;
 639                         error = _bus_dmamap_load_buffer(dmat,
 640                                         m->m_data, m->m_len,
 641                                         curthread, flags, &lastaddr,
 642                                         &nsegs, first);
 643                         first = 0;
 644                 }
 645         } else {
 646                 error = EINVAL;
 647         }
 648
 649         if (error) {
 650                 /* force "no valid mappings" in callback */
 651                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 652         } else {
 653                 (*callback)(callback_arg, dmat->segments,
 654                             nsegs+1, m0->m_pkthdr.len, error);
 655         }
 656         return (error);
 657 }
 658
 659 /*
 660  * Like _bus_dmamap_load(), but for uios.
 661  */
 662 int
 663 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 664                     struct uio *uio,
 665                     bus_dmamap_callback2_t *callback, void *callback_arg,
 666                     int flags)
 667 {
 668         vm_offset_t lastaddr;
 669         int nsegs, error, first, i;
 670         bus_size_t resid;
 671         struct iovec *iov;
 672         struct thread *td = NULL;
 673
 674         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 675                 ("bus_dmamap_load_uio: No support for bounce pages!"));
 676
 677         resid = uio->uio_resid;
 678         iov = uio->uio_iov;
 679
 680         if (uio->uio_segflg == UIO_USERSPACE) {
 681                 td = uio->uio_td;
 682                 KASSERT(td != NULL && td->td_proc != NULL,
 683                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 684         }
 685
 686         nsegs = 0;
 687         error = 0;
 688         first = 1;
 689         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 690                 /*
 691                  * Now at the first iovec to load.  Load each iovec
 692                  * until we have exhausted the residual count.
 693                  */
 694                 bus_size_t minlen =
 695                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 696                 caddr_t addr = (caddr_t) iov[i].iov_base;
 697
 698                 error = _bus_dmamap_load_buffer(dmat,
 699                                 addr, minlen,
 700                                 td, flags, &lastaddr, &nsegs, first);
 701                 first = 0;
 702
 703                 resid -= minlen;
 704         }
 705
 706         if (error) {
 707                 /* force "no valid mappings" in callback */
 708                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 709         } else {
 710                 (*callback)(callback_arg, dmat->segments,
 711                             nsegs+1, uio->uio_resid, error);
 712         }
 713         return (error);
 714 }
 715
 716 /*
 717  * Release the mapping held by map.
 718  */
 719 void
 720 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 721 {
 722         struct bounce_page *bpage;
 723
 724         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 725                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 726                 free_bounce_page(dmat, bpage);
 727         }
 728 }
 729
 730 void
 731 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 732 {
 733         struct bounce_page *bpage;
 734
 735         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 736
 737                 /*
 738                  * Handle data bouncing.  We might also
 739                  * want to add support for invalidating
 740                  * the caches on broken hardware
 741                  */
 742                 switch (op) {
 743                 case BUS_DMASYNC_PREWRITE:
 744                         while (bpage != NULL) {
 745                                 bcopy((void *)bpage->datavaddr,
 746                                       (void *)bpage->vaddr,
 747                                       bpage->datacount);
 748                                 bpage = STAILQ_NEXT(bpage, links);
 749                         }
 750                         break;
 751
 752                 case BUS_DMASYNC_POSTREAD:
 753                         while (bpage != NULL) {
 754                                 bcopy((void *)bpage->vaddr,
 755                                       (void *)bpage->datavaddr,
 756                                       bpage->datacount);
 757                                 bpage = STAILQ_NEXT(bpage, links);
 758                         }
 759                         break;
 760                 case BUS_DMASYNC_PREREAD:
 761                 case BUS_DMASYNC_POSTWRITE:
 762                         /* No-ops */
 763                         break;
 764                 }
 765         }
 766 }
 767
 768 static int
 769 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
 770 {
 771         int count;
 772
 773         count = 0;
 774         if (total_bpages == 0) {
 775                 STAILQ_INIT(&bounce_page_list);
 776                 STAILQ_INIT(&bounce_map_waitinglist);
 777                 STAILQ_INIT(&bounce_map_callbacklist);
 778         }
 779
 780         while (numpages > 0) {
 781                 struct bounce_page *bpage;
 782
 783                 bpage = (struct bounce_page *)kmalloc(sizeof(*bpage), M_DEVBUF,
 784                                                      M_INTWAIT);
 785
 786                 if (bpage == NULL)
 787                         break;
 788                 bzero(bpage, sizeof(*bpage));
 789                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
 790                                                          M_NOWAIT, 0ul,
 791                                                          dmat->lowaddr,
 792                                                          PAGE_SIZE,
 793                                                          0);
 794                 if (bpage->vaddr == NULL) {
 795                         kfree(bpage, M_DEVBUF);
 796                         break;
 797                 }
 798                 bpage->busaddr = pmap_kextract(bpage->vaddr);
 799                 crit_enter();
 800                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
 801                 total_bpages++;
 802                 free_bpages++;
 803                 crit_exit();
 804                 count++;
 805                 numpages--;
 806         }
 807         return (count);
 808 }
 809
 810 static int
 811 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
 812 {
 813         int pages;
 814
 815         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
 816         free_bpages -= pages;
 817         reserved_bpages += pages;
 818         map->pagesreserved += pages;
 819         pages = map->pagesneeded - map->pagesreserved;
 820
 821         return (pages);
 822 }
 823
 824 static bus_addr_t
 825 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 826                 bus_size_t size)
 827 {
 828         struct bounce_page *bpage;
 829
 830         if (map->pagesneeded == 0)
 831                 panic("add_bounce_page: map doesn't need any pages");
 832         map->pagesneeded--;
 833
 834         if (map->pagesreserved == 0)
 835                 panic("add_bounce_page: map doesn't need any pages");
 836         map->pagesreserved--;
 837
 838         crit_enter();
 839         bpage = STAILQ_FIRST(&bounce_page_list);
 840         if (bpage == NULL)
 841                 panic("add_bounce_page: free page list is empty");
 842
 843         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
 844         reserved_bpages--;
 845         active_bpages++;
 846         crit_exit();
 847
 848         bpage->datavaddr = vaddr;
 849         bpage->datacount = size;
 850         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 851         return (bpage->busaddr);
 852 }
 853
 854 static void
 855 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 856 {
 857         struct bus_dmamap *map;
 858
 859         bpage->datavaddr = 0;
 860         bpage->datacount = 0;
 861
 862         crit_enter();
 863         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
 864         free_bpages++;
 865         active_bpages--;
 866         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
 867                 if (reserve_bounce_pages(map->dmat, map) == 0) {
 868                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
 869                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
 870                                            map, links);
 871                         busdma_swi_pending = 1;
 872                         setsoftvm();
 873                 }
 874         }
 875         crit_exit();
 876 }
 877
 878 void
 879 busdma_swi(void)
 880 {
 881         struct bus_dmamap *map;
 882
 883         crit_enter();
 884         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
 885                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
 886                 crit_exit();
 887                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
 888                                 map->callback, map->callback_arg, /*flags*/0);
 889                 crit_enter();
 890         }
 891         crit_exit();
 892 }