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 1.21 2007/07/14 07:29:30 sephe 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 1024
  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
 293                         pages = MAX(atop(dmat->maxsize), 1);
 294                         pages = MIN(maxpages - total_bpages, pages);
 295                         pages = MAX(pages, 1);
 296                         if (alloc_bounce_pages(dmat, pages) < pages)
 297                                 error = ENOMEM;
 298
 299                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 300                                 if (error == 0)
 301                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 302                         } else {
 303                                 error = 0;
 304                         }
 305                 }
 306         } else {
 307                 *mapp = NULL;
 308         }
 309         if (error == 0)
 310                 dmat->map_count++;
 311         return (error);
 312 }
 313
 314 /*
 315  * Destroy a handle for mapping from kva/uva/physical
 316  * address space into bus device space.
 317  */
 318 int
 319 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 320 {
 321         if (map != NULL) {
 322                 if (STAILQ_FIRST(&map->bpages) != NULL)
 323                         return (EBUSY);
 324                 kfree(map, M_DEVBUF);
 325         }
 326         dmat->map_count--;
 327         return (0);
 328 }
 329
 330
 331 /*
 332  * Allocate a piece of memory that can be efficiently mapped into
 333  * bus device space based on the constraints lited in the dma tag.
 334  *
 335  * mapp is degenerate.  By definition this allocation should not require
 336  * bounce buffers so do not allocate a dma map.
 337  */
 338 int
 339 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 340                  bus_dmamap_t *mapp)
 341 {
 342         int mflags;
 343         /* If we succeed, no mapping/bouncing will be required */
 344         *mapp = NULL;
 345
 346         if (dmat->segments == NULL) {
 347                 KKASSERT(dmat->nsegments < 16384);
 348                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 349                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 350         }
 351
 352         if (flags & BUS_DMA_NOWAIT)
 353                 mflags = M_NOWAIT;
 354         else
 355                 mflags = M_WAITOK;
 356         if (flags & BUS_DMA_ZERO)
 357                 mflags |= M_ZERO;
 358
 359         if ((dmat->maxsize <= PAGE_SIZE) &&
 360             dmat->lowaddr >= ptoa(Maxmem)) {
 361                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 362                 /*
 363                  * XXX Check whether the allocation crossed a page boundary
 364                  * and retry with power-of-2 alignment in that case.
 365                  */
 366                 if ((((intptr_t)*vaddr) & PAGE_MASK) !=
 367                     (((intptr_t)*vaddr + dmat->maxsize) & PAGE_MASK)) {
 368                         size_t size;
 369                         kfree(*vaddr, M_DEVBUF);
 370                         /* XXX check for overflow? */
 371                         for (size = 1; size <= dmat->maxsize; size <<= 1)
 372                                 ;
 373                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 374                 }
 375         } else {
 376                 /*
 377                  * XXX Use Contigmalloc until it is merged into this facility
 378                  *     and handles multi-seg allocations.  Nobody is doing
 379                  *     multi-seg allocations yet though.
 380                  */
 381                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 382                     0ul, dmat->lowaddr, dmat->alignment? dmat->alignment : 1ul,
 383                     dmat->boundary);
 384         }
 385         if (*vaddr == NULL)
 386                 return (ENOMEM);
 387         return (0);
 388 }
 389
 390 /*
 391  * Free a piece of memory and it's allociated dmamap, that was allocated
 392  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 393  */
 394 void
 395 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 396 {
 397         /*
 398          * dmamem does not need to be bounced, so the map should be
 399          * NULL
 400          */
 401         if (map != NULL)
 402                 panic("bus_dmamem_free: Invalid map freed\n");
 403         if ((dmat->maxsize <= PAGE_SIZE) &&
 404             dmat->lowaddr >= ptoa(Maxmem))
 405                 kfree(vaddr, M_DEVBUF);
 406         else
 407                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 408 }
 409
 410 #define BUS_DMAMAP_NSEGS ((BUS_SPACE_MAXSIZE / PAGE_SIZE) + 1)
 411
 412 /*
 413  * Map the buffer buf into bus space using the dmamap map.
 414  */
 415 int
 416 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 417                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 418                 void *callback_arg, int flags)
 419 {
 420         vm_offset_t             vaddr;
 421         vm_paddr_t              paddr;
 422         bus_dma_segment_t      *sg;
 423         int                     seg;
 424         int                     error;
 425         vm_paddr_t              nextpaddr;
 426         bus_addr_t              bmask;
 427
 428         if (map == NULL)
 429                 map = &nobounce_dmamap;
 430
 431         error = 0;
 432         /*
 433          * If we are being called during a callback, pagesneeded will
 434          * be non-zero, so we can avoid doing the work twice.
 435          */
 436         if (dmat->lowaddr < ptoa(Maxmem) &&
 437             map->pagesneeded == 0) {
 438                 vm_offset_t     vendaddr;
 439
 440                 /*
 441                  * Count the number of bounce pages
 442                  * needed in order to complete this transfer
 443                  */
 444                 vaddr = trunc_page((vm_offset_t)buf);
 445                 vendaddr = (vm_offset_t)buf + buflen;
 446
 447                 while (vaddr < vendaddr) {
 448                         paddr = pmap_kextract(vaddr);
 449                         if (run_filter(dmat, paddr) != 0) {
 450
 451                                 map->pagesneeded++;
 452                         }
 453                         vaddr += PAGE_SIZE;
 454                 }
 455         }
 456
 457         /* Reserve Necessary Bounce Pages */
 458         if (map->pagesneeded != 0) {
 459                 crit_enter();
 460                 if (reserve_bounce_pages(dmat, map) != 0) {
 461
 462                         /* Queue us for resources */
 463                         map->dmat = dmat;
 464                         map->buf = buf;
 465                         map->buflen = buflen;
 466                         map->callback = callback;
 467                         map->callback_arg = callback_arg;
 468
 469                         STAILQ_INSERT_TAIL(&bounce_map_waitinglist, map, links);
 470                         crit_exit();
 471
 472                         return (EINPROGRESS);
 473                 }
 474                 crit_exit();
 475         }
 476
 477         vaddr = (vm_offset_t)buf;
 478         sg = dmat->segments;
 479         seg = 1;
 480         sg->ds_len = 0;
 481         nextpaddr = 0;
 482         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 483
 484         /* force at least one segment */
 485         do {
 486                 bus_size_t      size;
 487
 488                 /*
 489                  * Per-page main loop
 490                  */
 491                 paddr = pmap_kextract(vaddr);
 492                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 493                 if (size > buflen)
 494                         size = buflen;
 495                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 496                         /*
 497                          * note: this paddr has the same in-page offset
 498                          * as vaddr and thus the paddr above, so the
 499                          * size does not have to be recalculated
 500                          */
 501                         paddr = add_bounce_page(dmat, map, vaddr, size);
 502                 }
 503
 504                 /*
 505                  * Fill in the bus_dma_segment
 506                  */
 507                 if (sg->ds_len == 0) {
 508                         sg->ds_addr = paddr;
 509                         sg->ds_len = size;
 510                 } else if (paddr == nextpaddr) {
 511                         sg->ds_len += size;
 512                 } else {
 513                         sg++;
 514                         seg++;
 515                         if (seg > dmat->nsegments)
 516                                 break;
 517                         sg->ds_addr = paddr;
 518                         sg->ds_len = size;
 519                 }
 520                 nextpaddr = paddr + size;
 521
 522                 /*
 523                  * Handle maxsegsz and boundary issues with a nested loop
 524                  */
 525                 for (;;) {
 526                         bus_size_t      tmpsize;
 527
 528                         /*
 529                          * Limit to the boundary and maximum segment size
 530                          */
 531                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 532                                 tmpsize = dmat->boundary -
 533                                           (sg->ds_addr & ~bmask);
 534                                 if (tmpsize > dmat->maxsegsz)
 535                                         tmpsize = dmat->maxsegsz;
 536                                 KKASSERT(tmpsize < sg->ds_len);
 537                         } else if (sg->ds_len > dmat->maxsegsz) {
 538                                 tmpsize = dmat->maxsegsz;
 539                         } else {
 540                                 break;
 541                         }
 542
 543                         /*
 544                          * Futz, split the data into a new segment.
 545                          */
 546                         if (seg >= dmat->nsegments)
 547                                 goto fail;
 548                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 549                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 550                         sg[0].ds_len = tmpsize;
 551                         sg++;
 552                         seg++;
 553                 }
 554
 555                 /*
 556                  * Adjust for loop
 557                  */
 558                 buflen -= size;
 559                 vaddr += size;
 560         } while (buflen > 0);
 561
 562 fail:
 563         if (buflen != 0) {
 564                 kprintf("bus_dmamap_load: Too many segs! buf_len = 0x%lx\n",
 565                        (u_long)buflen);
 566                 error = EFBIG;
 567         }
 568
 569         (*callback)(callback_arg, dmat->segments, seg, error);
 570
 571         return (0);
 572 }
 573
 574 /*
 575  * Utility function to load a linear buffer.  lastaddrp holds state
 576  * between invocations (for multiple-buffer loads).  segp contains
 577  * the starting segment on entrace, and the ending segment on exit.
 578  * first indicates if this is the first invocation of this function.
 579  */
 580 static int
 581 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 582                         void *buf, bus_size_t buflen,
 583                         struct thread *td,
 584                         int flags,
 585                         vm_offset_t *lastaddrp,
 586                         int *segp,
 587                         int first)
 588 {
 589         bus_dma_segment_t *segs;
 590         bus_size_t sgsize;
 591         bus_addr_t curaddr, lastaddr, baddr, bmask;
 592         vm_offset_t vaddr = (vm_offset_t)buf;
 593         int seg;
 594         pmap_t pmap;
 595
 596         if (td->td_proc != NULL)
 597                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 598         else
 599                 pmap = NULL;
 600
 601         segs = dmat->segments;
 602         lastaddr = *lastaddrp;
 603         bmask  = ~(dmat->boundary - 1);
 604
 605         for (seg = *segp; buflen > 0 ; ) {
 606                 /*
 607                  * Get the physical address for this segment.
 608                  */
 609                 if (pmap)
 610                         curaddr = pmap_extract(pmap, vaddr);
 611                 else
 612                         curaddr = pmap_kextract(vaddr);
 613
 614                 /*
 615                  * Compute the segment size, and adjust counts.
 616                  */
 617                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
 618                 if (buflen < sgsize)
 619                         sgsize = buflen;
 620
 621                 /*
 622                  * Make sure we don't cross any boundaries.
 623                  */
 624                 if (dmat->boundary > 0) {
 625                         baddr = (curaddr + dmat->boundary) & bmask;
 626                         if (sgsize > (baddr - curaddr))
 627                                 sgsize = (baddr - curaddr);
 628                 }
 629
 630                 /*
 631                  * Insert chunk into a segment, coalescing with
 632                  * previous segment if possible.
 633                  */
 634                 if (first) {
 635                         segs[seg].ds_addr = curaddr;
 636                         segs[seg].ds_len = sgsize;
 637                         first = 0;
 638                 } else {
 639                         if (curaddr == lastaddr &&
 640                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 641                             (dmat->boundary == 0 ||
 642                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 643                                 segs[seg].ds_len += sgsize;
 644                         else {
 645                                 if (++seg >= dmat->nsegments)
 646                                         break;
 647                                 segs[seg].ds_addr = curaddr;
 648                                 segs[seg].ds_len = sgsize;
 649                         }
 650                 }
 651
 652                 lastaddr = curaddr + sgsize;
 653                 vaddr += sgsize;
 654                 buflen -= sgsize;
 655         }
 656
 657         *segp = seg;
 658         *lastaddrp = lastaddr;
 659
 660         /*
 661          * Did we fit?
 662          */
 663         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 664 }
 665
 666 /*
 667  * Like _bus_dmamap_load(), but for mbufs.
 668  */
 669 int
 670 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 671                      struct mbuf *m0,
 672                      bus_dmamap_callback2_t *callback, void *callback_arg,
 673                      int flags)
 674 {
 675         int nsegs, error;
 676
 677         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 678                 ("bus_dmamap_load_mbuf: No support for bounce pages!"));
 679         KASSERT(m0->m_flags & M_PKTHDR,
 680                 ("bus_dmamap_load_mbuf: no packet header"));
 681
 682         nsegs = 0;
 683         error = 0;
 684         if (m0->m_pkthdr.len <= dmat->maxsize) {
 685                 int first = 1;
 686                 vm_offset_t lastaddr = 0;
 687                 struct mbuf *m;
 688
 689                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 690                         if ( m->m_len == 0 )
 691                                 continue;
 692                         error = _bus_dmamap_load_buffer(dmat,
 693                                         m->m_data, m->m_len,
 694                                         curthread, flags, &lastaddr,
 695                                         &nsegs, first);
 696                         first = 0;
 697                 }
 698         } else {
 699                 error = EINVAL;
 700         }
 701
 702         if (error) {
 703                 /* force "no valid mappings" in callback */
 704                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 705         } else {
 706                 (*callback)(callback_arg, dmat->segments,
 707                             nsegs+1, m0->m_pkthdr.len, error);
 708         }
 709         return (error);
 710 }
 711
 712 /*
 713  * Like _bus_dmamap_load(), but for uios.
 714  */
 715 int
 716 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 717                     struct uio *uio,
 718                     bus_dmamap_callback2_t *callback, void *callback_arg,
 719                     int flags)
 720 {
 721         vm_offset_t lastaddr;
 722         int nsegs, error, first, i;
 723         bus_size_t resid;
 724         struct iovec *iov;
 725         struct thread *td = NULL;
 726
 727         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 728                 ("bus_dmamap_load_uio: No support for bounce pages!"));
 729
 730         resid = uio->uio_resid;
 731         iov = uio->uio_iov;
 732
 733         if (uio->uio_segflg == UIO_USERSPACE) {
 734                 td = uio->uio_td;
 735                 KASSERT(td != NULL && td->td_proc != NULL,
 736                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 737         }
 738
 739         nsegs = 0;
 740         error = 0;
 741         first = 1;
 742         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 743                 /*
 744                  * Now at the first iovec to load.  Load each iovec
 745                  * until we have exhausted the residual count.
 746                  */
 747                 bus_size_t minlen =
 748                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 749                 caddr_t addr = (caddr_t) iov[i].iov_base;
 750
 751                 error = _bus_dmamap_load_buffer(dmat,
 752                                 addr, minlen,
 753                                 td, flags, &lastaddr, &nsegs, first);
 754                 first = 0;
 755
 756                 resid -= minlen;
 757         }
 758
 759         if (error) {
 760                 /* force "no valid mappings" in callback */
 761                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 762         } else {
 763                 (*callback)(callback_arg, dmat->segments,
 764                             nsegs+1, uio->uio_resid, error);
 765         }
 766         return (error);
 767 }
 768
 769 /*
 770  * Release the mapping held by map.
 771  */
 772 void
 773 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 774 {
 775         struct bounce_page *bpage;
 776
 777         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 778                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 779                 free_bounce_page(dmat, bpage);
 780         }
 781 }
 782
 783 void
 784 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 785 {
 786         struct bounce_page *bpage;
 787
 788         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 789
 790                 /*
 791                  * Handle data bouncing.  We might also
 792                  * want to add support for invalidating
 793                  * the caches on broken hardware
 794                  */
 795                 switch (op) {
 796                 case BUS_DMASYNC_PREWRITE:
 797                         while (bpage != NULL) {
 798                                 bcopy((void *)bpage->datavaddr,
 799                                       (void *)bpage->vaddr,
 800                                       bpage->datacount);
 801                                 bpage = STAILQ_NEXT(bpage, links);
 802                         }
 803                         break;
 804
 805                 case BUS_DMASYNC_POSTREAD:
 806                         while (bpage != NULL) {
 807                                 bcopy((void *)bpage->vaddr,
 808                                       (void *)bpage->datavaddr,
 809                                       bpage->datacount);
 810                                 bpage = STAILQ_NEXT(bpage, links);
 811                         }
 812                         break;
 813                 case BUS_DMASYNC_PREREAD:
 814                 case BUS_DMASYNC_POSTWRITE:
 815                         /* No-ops */
 816                         break;
 817                 }
 818         }
 819 }
 820
 821 static int
 822 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
 823 {
 824         int count;
 825
 826         count = 0;
 827         if (total_bpages == 0) {
 828                 STAILQ_INIT(&bounce_page_list);
 829                 STAILQ_INIT(&bounce_map_waitinglist);
 830                 STAILQ_INIT(&bounce_map_callbacklist);
 831         }
 832
 833         while (numpages > 0) {
 834                 struct bounce_page *bpage;
 835
 836                 bpage = (struct bounce_page *)kmalloc(sizeof(*bpage), M_DEVBUF,
 837                                                      M_INTWAIT);
 838
 839                 if (bpage == NULL)
 840                         break;
 841                 bzero(bpage, sizeof(*bpage));
 842                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
 843                                                          M_NOWAIT, 0ul,
 844                                                          dmat->lowaddr,
 845                                                          PAGE_SIZE,
 846                                                          0);
 847                 if (bpage->vaddr == NULL) {
 848                         kfree(bpage, M_DEVBUF);
 849                         break;
 850                 }
 851                 bpage->busaddr = pmap_kextract(bpage->vaddr);
 852                 crit_enter();
 853                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
 854                 total_bpages++;
 855                 free_bpages++;
 856                 crit_exit();
 857                 count++;
 858                 numpages--;
 859         }
 860         return (count);
 861 }
 862
 863 static int
 864 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
 865 {
 866         int pages;
 867
 868         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
 869         free_bpages -= pages;
 870         reserved_bpages += pages;
 871         map->pagesreserved += pages;
 872         pages = map->pagesneeded - map->pagesreserved;
 873
 874         return (pages);
 875 }
 876
 877 static bus_addr_t
 878 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 879                 bus_size_t size)
 880 {
 881         struct bounce_page *bpage;
 882
 883         if (map->pagesneeded == 0)
 884                 panic("add_bounce_page: map doesn't need any pages");
 885         map->pagesneeded--;
 886
 887         if (map->pagesreserved == 0)
 888                 panic("add_bounce_page: map doesn't need any pages");
 889         map->pagesreserved--;
 890
 891         crit_enter();
 892         bpage = STAILQ_FIRST(&bounce_page_list);
 893         if (bpage == NULL)
 894                 panic("add_bounce_page: free page list is empty");
 895
 896         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
 897         reserved_bpages--;
 898         active_bpages++;
 899         crit_exit();
 900
 901         bpage->datavaddr = vaddr;
 902         bpage->datacount = size;
 903         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 904         return (bpage->busaddr);
 905 }
 906
 907 static void
 908 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 909 {
 910         struct bus_dmamap *map;
 911
 912         bpage->datavaddr = 0;
 913         bpage->datacount = 0;
 914
 915         crit_enter();
 916         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
 917         free_bpages++;
 918         active_bpages--;
 919         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
 920                 if (reserve_bounce_pages(map->dmat, map) == 0) {
 921                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
 922                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
 923                                            map, links);
 924                         busdma_swi_pending = 1;
 925                         setsoftvm();
 926                 }
 927         }
 928         crit_exit();
 929 }
 930
 931 void
 932 busdma_swi(void)
 933 {
 934         struct bus_dmamap *map;
 935
 936         crit_enter();
 937         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
 938                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
 939                 crit_exit();
 940                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
 941                                 map->callback, map->callback_arg, /*flags*/0);
 942                 crit_enter();
 943         }
 944         crit_exit();
 945 }