sys/platform/vkernel/platform/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/vkernel/platform/busdma_machdep.c,v 1.3 2008/06/06 13:19:25 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 | M_ZERO);
 267                 if (*mapp == NULL)
 268                         return (ENOMEM);
 269                 /* Initialize the new map */
 270                 STAILQ_INIT(&((*mapp)->bpages));
 271                 /*
 272                  * Attempt to add pages to our pool on a per-instance
 273                  * basis up to a sane limit.
 274                  */
 275                 maxpages = MIN(MAX_BPAGES, Maxmem - atop(dmat->lowaddr));
 276                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 277                  || (dmat->map_count > 0
 278                   && total_bpages < maxpages)) {
 279                         int pages;
 280
 281                         if (dmat->lowaddr > bounce_lowaddr) {
 282                                 /*
 283                                  * Go through the pool and kill any pages
 284                                  * that don't reside below lowaddr.
 285                                  */
 286                                 panic("bus_dmamap_create: page reallocation "
 287                                       "not implemented");
 288                         }
 289                         pages = atop(dmat->maxsize);
 290                         pages = MIN(maxpages - total_bpages, pages);
 291                         error = alloc_bounce_pages(dmat, pages);
 292
 293                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 294                                 if (error == 0)
 295                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 296                         } else {
 297                                 error = 0;
 298                         }
 299                 }
 300         } else {
 301                 *mapp = NULL;
 302         }
 303         if (error == 0)
 304                 dmat->map_count++;
 305         return (error);
 306 }
 307
 308 /*
 309  * Destroy a handle for mapping from kva/uva/physical
 310  * address space into bus device space.
 311  */
 312 int
 313 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 314 {
 315         if (map != NULL) {
 316                 if (STAILQ_FIRST(&map->bpages) != NULL)
 317                         return (EBUSY);
 318                 kfree(map, M_DEVBUF);
 319         }
 320         dmat->map_count--;
 321         return (0);
 322 }
 323
 324
 325 /*
 326  * Allocate a piece of memory that can be efficiently mapped into
 327  * bus device space based on the constraints lited in the dma tag.
 328  *
 329  * mapp is degenerate.  By definition this allocation should not require
 330  * bounce buffers so do not allocate a dma map.
 331  */
 332 int
 333 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 334                  bus_dmamap_t *mapp)
 335 {
 336         int mflags;
 337         /* If we succeed, no mapping/bouncing will be required */
 338         *mapp = NULL;
 339
 340         if (dmat->segments == NULL) {
 341                 KKASSERT(dmat->nsegments < 16384);
 342                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 343                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 344         }
 345
 346         if (flags & BUS_DMA_NOWAIT)
 347                 mflags = M_NOWAIT;
 348         else
 349                 mflags = M_WAITOK;
 350         if (flags & BUS_DMA_ZERO)
 351                 mflags |= M_ZERO;
 352
 353         if ((dmat->maxsize <= PAGE_SIZE) &&
 354             dmat->lowaddr >= ptoa(Maxmem)) {
 355                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 356                 /*
 357                  * XXX Check whether the allocation crossed a page boundary
 358                  * and retry with power-of-2 alignment in that case.
 359                  */
 360                 if ((((intptr_t)*vaddr) & PAGE_MASK) !=
 361                     (((intptr_t)*vaddr + dmat->maxsize) & PAGE_MASK)) {
 362                         size_t size;
 363                         kfree(*vaddr, M_DEVBUF);
 364                         /* XXX check for overflow? */
 365                         for (size = 1; size <= dmat->maxsize; size <<= 1)
 366                                 ;
 367                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 368                 }
 369         } else {
 370                 /*
 371                  * XXX Use Contigmalloc until it is merged into this facility
 372                  *     and handles multi-seg allocations.  Nobody is doing
 373                  *     multi-seg allocations yet though.
 374                  */
 375                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 376                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 377                     dmat->boundary);
 378         }
 379         if (*vaddr == NULL)
 380                 return (ENOMEM);
 381         return (0);
 382 }
 383
 384 /*
 385  * Free a piece of memory and it's allociated dmamap, that was allocated
 386  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 387  */
 388 void
 389 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 390 {
 391         /*
 392          * dmamem does not need to be bounced, so the map should be
 393          * NULL
 394          */
 395         if (map != NULL)
 396                 panic("bus_dmamem_free: Invalid map freed\n");
 397         if ((dmat->maxsize <= PAGE_SIZE) &&
 398             dmat->lowaddr >= ptoa(Maxmem))
 399                 kfree(vaddr, M_DEVBUF);
 400         else
 401                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 402 }
 403
 404 #define BUS_DMAMAP_NSEGS ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
 405
 406 /*
 407  * Map the buffer buf into bus space using the dmamap map.
 408  */
 409 int
 410 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 411                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 412                 void *callback_arg, int flags)
 413 {
 414         vm_offset_t             vaddr;
 415         vm_paddr_t              paddr;
 416         bus_dma_segment_t      *sg;
 417         int                     seg;
 418         int                     error;
 419         vm_paddr_t              nextpaddr;
 420
 421         if (map == NULL)
 422                 map = &nobounce_dmamap;
 423
 424         error = 0;
 425         /*
 426          * If we are being called during a callback, pagesneeded will
 427          * be non-zero, so we can avoid doing the work twice.
 428          */
 429         if (dmat->lowaddr < ptoa(Maxmem) &&
 430             map->pagesneeded == 0) {
 431                 vm_offset_t     vendaddr;
 432
 433                 /*
 434                  * Count the number of bounce pages
 435                  * needed in order to complete this transfer
 436                  */
 437                 vaddr = trunc_page((vm_offset_t)buf);
 438                 vendaddr = (vm_offset_t)buf + buflen;
 439
 440                 while (vaddr < vendaddr) {
 441                         paddr = pmap_kextract(vaddr);
 442                         if (run_filter(dmat, paddr) != 0) {
 443
 444                                 map->pagesneeded++;
 445                         }
 446                         vaddr += PAGE_SIZE;
 447                 }
 448         }
 449
 450         /* Reserve Necessary Bounce Pages */
 451         if (map->pagesneeded != 0) {
 452                 crit_enter();
 453                 if (reserve_bounce_pages(dmat, map) != 0) {
 454
 455                         /* Queue us for resources */
 456                         map->dmat = dmat;
 457                         map->buf = buf;
 458                         map->buflen = buflen;
 459                         map->callback = callback;
 460                         map->callback_arg = callback_arg;
 461
 462                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 463                         crit_exit();
 464
 465                         return (EINPROGRESS);
 466                 }
 467                 crit_exit();
 468         }
 469
 470         vaddr = (vm_offset_t)buf;
 471         sg = dmat->segments;
 472         seg = 1;
 473         sg->ds_len = 0;
 474
 475         nextpaddr = 0;
 476         do {
 477                 bus_size_t      size;
 478
 479                 paddr = pmap_kextract(vaddr);
 480                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 481                 if (size > buflen)
 482                         size = buflen;
 483
 484                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 485                         paddr = add_bounce_page(dmat, map, vaddr, size);
 486                 }
 487
 488                 if (sg->ds_len == 0) {
 489                         sg->ds_addr = paddr;
 490                         sg->ds_len = size;
 491                 } else if (paddr == nextpaddr) {
 492                         sg->ds_len += size;
 493                 } else {
 494                         /* Go to the next segment */
 495                         sg++;
 496                         seg++;
 497                         if (seg > dmat->nsegments)
 498                                 break;
 499                         sg->ds_addr = paddr;
 500                         sg->ds_len = size;
 501                 }
 502                 vaddr += size;
 503                 nextpaddr = paddr + size;
 504                 buflen -= size;
 505         } while (buflen > 0);
 506
 507         if (buflen != 0) {
 508                 kprintf("bus_dmamap_load: Too many segs! buf_len = 0x%lx\n",
 509                        (u_long)buflen);
 510                 error = EFBIG;
 511         }
 512
 513         (*callback)(callback_arg, dmat->segments, seg, error);
 514
 515         return (0);
 516 }
 517
 518 /*
 519  * Utility function to load a linear buffer.  lastaddrp holds state
 520  * between invocations (for multiple-buffer loads).  segp contains
 521  * the starting segment on entrace, and the ending segment on exit.
 522  * first indicates if this is the first invocation of this function.
 523  */
 524 static int
 525 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 526                         void *buf, bus_size_t buflen,
 527                         struct thread *td,
 528                         int flags,
 529                         vm_offset_t *lastaddrp,
 530                         int *segp,
 531                         int first)
 532 {
 533         bus_dma_segment_t *segs;
 534         bus_size_t sgsize;
 535         bus_addr_t curaddr, lastaddr, baddr, bmask;
 536         vm_offset_t vaddr = (vm_offset_t)buf;
 537         int seg;
 538         pmap_t pmap;
 539
 540         if (td->td_proc != NULL)
 541                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 542         else
 543                 pmap = NULL;
 544
 545         segs = dmat->segments;
 546         lastaddr = *lastaddrp;
 547         bmask  = ~(dmat->boundary - 1);
 548
 549         for (seg = *segp; buflen > 0 ; ) {
 550                 /*
 551                  * Get the physical address for this segment.
 552                  */
 553                 if (pmap)
 554                         curaddr = pmap_extract(pmap, vaddr);
 555                 else
 556                         curaddr = pmap_kextract(vaddr);
 557
 558                 /*
 559                  * Compute the segment size, and adjust counts.
 560                  */
 561                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
 562                 if (buflen < sgsize)
 563                         sgsize = buflen;
 564
 565                 /*
 566                  * Make sure we don't cross any boundaries.
 567                  */
 568                 if (dmat->boundary > 0) {
 569                         baddr = (curaddr + dmat->boundary) & bmask;
 570                         if (sgsize > (baddr - curaddr))
 571                                 sgsize = (baddr - curaddr);
 572                 }
 573
 574                 /*
 575                  * Insert chunk into a segment, coalescing with
 576                  * previous segment if possible.
 577                  */
 578                 if (first) {
 579                         segs[seg].ds_addr = curaddr;
 580                         segs[seg].ds_len = sgsize;
 581                         first = 0;
 582                 } else {
 583                         if (curaddr == lastaddr &&
 584                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 585                             (dmat->boundary == 0 ||
 586                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 587                                 segs[seg].ds_len += sgsize;
 588                         else {
 589                                 if (++seg >= dmat->nsegments)
 590                                         break;
 591                                 segs[seg].ds_addr = curaddr;
 592                                 segs[seg].ds_len = sgsize;
 593                         }
 594                 }
 595
 596                 lastaddr = curaddr + sgsize;
 597                 vaddr += sgsize;
 598                 buflen -= sgsize;
 599         }
 600
 601         *segp = seg;
 602         *lastaddrp = lastaddr;
 603
 604         /*
 605          * Did we fit?
 606          */
 607         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 608 }
 609
 610 /*
 611  * Like _bus_dmamap_load(), but for mbufs.
 612  */
 613 int
 614 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 615                      struct mbuf *m0,
 616                      bus_dmamap_callback2_t *callback, void *callback_arg,
 617                      int flags)
 618 {
 619         int nsegs, error;
 620
 621         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 622                 ("bus_dmamap_load_mbuf: No support for bounce pages!"));
 623         KASSERT(m0->m_flags & M_PKTHDR,
 624                 ("bus_dmamap_load_mbuf: no packet header"));
 625
 626         nsegs = 0;
 627         error = 0;
 628         if (m0->m_pkthdr.len <= dmat->maxsize) {
 629                 int first = 1;
 630                 vm_offset_t lastaddr = 0;
 631                 struct mbuf *m;
 632
 633                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 634                         if ( m->m_len == 0 )
 635                                 continue;
 636                         error = _bus_dmamap_load_buffer(dmat,
 637                                         m->m_data, m->m_len,
 638                                         curthread, flags, &lastaddr,
 639                                         &nsegs, first);
 640                         first = 0;
 641                 }
 642         } else {
 643                 error = EINVAL;
 644         }
 645
 646         if (error) {
 647                 /* force "no valid mappings" in callback */
 648                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 649         } else {
 650                 (*callback)(callback_arg, dmat->segments,
 651                             nsegs+1, m0->m_pkthdr.len, error);
 652         }
 653         return (error);
 654 }
 655
 656 /*
 657  * Like _bus_dmamap_load(), but for uios.
 658  */
 659 int
 660 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 661                     struct uio *uio,
 662                     bus_dmamap_callback2_t *callback, void *callback_arg,
 663                     int flags)
 664 {
 665         vm_offset_t lastaddr;
 666         int nsegs, error, first, i;
 667         bus_size_t resid;
 668         struct iovec *iov;
 669         struct thread *td = NULL;
 670
 671         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 672                 ("bus_dmamap_load_uio: No support for bounce pages!"));
 673
 674         resid = uio->uio_resid;
 675         iov = uio->uio_iov;
 676
 677         if (uio->uio_segflg == UIO_USERSPACE) {
 678                 td = uio->uio_td;
 679                 KASSERT(td != NULL && td->td_proc != NULL,
 680                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 681         }
 682
 683         nsegs = 0;
 684         error = 0;
 685         first = 1;
 686         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 687                 /*
 688                  * Now at the first iovec to load.  Load each iovec
 689                  * until we have exhausted the residual count.
 690                  */
 691                 bus_size_t minlen =
 692                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 693                 caddr_t addr = (caddr_t) iov[i].iov_base;
 694
 695                 error = _bus_dmamap_load_buffer(dmat,
 696                                 addr, minlen,
 697                                 td, flags, &lastaddr, &nsegs, first);
 698                 first = 0;
 699
 700                 resid -= minlen;
 701         }
 702
 703         if (error) {
 704                 /* force "no valid mappings" in callback */
 705                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 706         } else {
 707                 (*callback)(callback_arg, dmat->segments,
 708                             nsegs+1, uio->uio_resid, error);
 709         }
 710         return (error);
 711 }
 712
 713 /*
 714  * Release the mapping held by map.
 715  */
 716 void
 717 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 718 {
 719         struct bounce_page *bpage;
 720
 721         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 722                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 723                 free_bounce_page(dmat, bpage);
 724         }
 725 }
 726
 727 void
 728 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 729 {
 730         struct bounce_page *bpage;
 731
 732         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 733
 734                 /*
 735                  * Handle data bouncing.  We might also
 736                  * want to add support for invalidating
 737                  * the caches on broken hardware
 738                  */
 739                 switch (op) {
 740                 case BUS_DMASYNC_PREWRITE:
 741                         while (bpage != NULL) {
 742                                 bcopy((void *)bpage->datavaddr,
 743                                       (void *)bpage->vaddr,
 744                                       bpage->datacount);
 745                                 bpage = STAILQ_NEXT(bpage, links);
 746                         }
 747                         break;
 748
 749                 case BUS_DMASYNC_POSTREAD:
 750                         while (bpage != NULL) {
 751                                 bcopy((void *)bpage->vaddr,
 752                                       (void *)bpage->datavaddr,
 753                                       bpage->datacount);
 754                                 bpage = STAILQ_NEXT(bpage, links);
 755                         }
 756                         break;
 757                 case BUS_DMASYNC_PREREAD:
 758                 case BUS_DMASYNC_POSTWRITE:
 759                         /* No-ops */
 760                         break;
 761                 }
 762         }
 763 }
 764
 765 static int
 766 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
 767 {
 768         int count;
 769
 770         count = 0;
 771         if (total_bpages == 0) {
 772                 STAILQ_INIT(&bounce_page_list);
 773                 STAILQ_INIT(&bounce_map_waitinglist);
 774                 STAILQ_INIT(&bounce_map_callbacklist);
 775         }
 776
 777         while (numpages > 0) {
 778                 struct bounce_page *bpage;
 779
 780                 bpage = (struct bounce_page *)kmalloc(sizeof(*bpage), M_DEVBUF,
 781                                                      M_INTWAIT | M_ZERO);
 782
 783                 if (bpage == NULL)
 784                         break;
 785                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
 786                                                          M_NOWAIT, 0ul,
 787                                                          dmat->lowaddr,
 788                                                          PAGE_SIZE,
 789                                                          0);
 790                 if (bpage->vaddr == 0) {
 791                         kfree(bpage, M_DEVBUF);
 792                         break;
 793                 }
 794                 bpage->busaddr = pmap_kextract(bpage->vaddr);
 795                 crit_enter();
 796                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
 797                 total_bpages++;
 798                 free_bpages++;
 799                 crit_exit();
 800                 count++;
 801                 numpages--;
 802         }
 803         return (count);
 804 }
 805
 806 static int
 807 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
 808 {
 809         int pages;
 810
 811         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
 812         free_bpages -= pages;
 813         reserved_bpages += pages;
 814         map->pagesreserved += pages;
 815         pages = map->pagesneeded - map->pagesreserved;
 816
 817         return (pages);
 818 }
 819
 820 static bus_addr_t
 821 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 822                 bus_size_t size)
 823 {
 824         struct bounce_page *bpage;
 825
 826         if (map->pagesneeded == 0)
 827                 panic("add_bounce_page: map doesn't need any pages");
 828         map->pagesneeded--;
 829
 830         if (map->pagesreserved == 0)
 831                 panic("add_bounce_page: map doesn't need any pages");
 832         map->pagesreserved--;
 833
 834         crit_enter();
 835         bpage = STAILQ_FIRST(&bounce_page_list);
 836         if (bpage == NULL)
 837                 panic("add_bounce_page: free page list is empty");
 838
 839         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
 840         reserved_bpages--;
 841         active_bpages++;
 842         crit_exit();
 843
 844         bpage->datavaddr = vaddr;
 845         bpage->datacount = size;
 846         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 847         return (bpage->busaddr);
 848 }
 849
 850 static void
 851 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 852 {
 853         struct bus_dmamap *map;
 854
 855         bpage->datavaddr = 0;
 856         bpage->datacount = 0;
 857
 858         crit_enter();
 859         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
 860         free_bpages++;
 861         active_bpages--;
 862         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
 863                 if (reserve_bounce_pages(map->dmat, map) == 0) {
 864                         panic("free_bounce_pages: uncoded\n");
 865 #if 0
 866                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
 867                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
 868                                            map, links);
 869                         busdma_swi_pending = 1;
 870                         setsoftvm();
 871 #endif
 872                 }
 873         }
 874         crit_exit();
 875 }
 876
 877 #if 0
 878
 879 void
 880 busdma_swi(void)
 881 {
 882         struct bus_dmamap *map;
 883
 884         crit_enter();
 885         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
 886                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
 887                 crit_exit();
 888                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
 889                                 map->callback, map->callback_arg, /*flags*/0);
 890                 crit_enter();
 891         }
 892         crit_exit();
 893 }
 894
 895 #endif
 896