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 1.23 2008/06/05 18:06:32 swildner Exp $
  28  */
  29
  30 #include <sys/param.h>
  31 #include <sys/systm.h>
  32 #include <sys/malloc.h>
  33 #include <sys/mbuf.h>
  34 #include <sys/uio.h>
  35 #include <sys/thread2.h>
  36 #include <sys/bus_dma.h>
  37 #include <sys/kernel.h>
  38 #include <sys/sysctl.h>
  39
  40 #include <vm/vm.h>
  41 #include <vm/vm_page.h>
  42
  43 /* XXX needed for to access pmap to convert per-proc virtual to physical */
  44 #include <sys/proc.h>
  45 #include <sys/lock.h>
  46 #include <vm/vm_map.h>
  47
  48 #include <machine/md_var.h>
  49
  50 #define MAX_BPAGES      1024
  51
  52 struct bus_dma_tag {
  53         bus_dma_tag_t   parent;
  54         bus_size_t      alignment;
  55         bus_size_t      boundary;
  56         bus_addr_t      lowaddr;
  57         bus_addr_t      highaddr;
  58         bus_dma_filter_t *filter;
  59         void            *filterarg;
  60         bus_size_t      maxsize;
  61         u_int           nsegments;
  62         bus_size_t      maxsegsz;
  63         int             flags;
  64         int             ref_count;
  65         int             map_count;
  66         bus_dma_segment_t *segments;
  67 };
  68
  69 /*
  70  * bus_dma_tag private flags
  71  */
  72 #define BUS_DMA_COULD_BOUNCE    BUS_DMA_BUS3
  73 #define BUS_DMA_MIN_ALLOC_COMP  BUS_DMA_BUS4
  74
  75 struct bounce_page {
  76         vm_offset_t     vaddr;          /* kva of bounce buffer */
  77         bus_addr_t      busaddr;        /* Physical address */
  78         vm_offset_t     datavaddr;      /* kva of client data */
  79         bus_size_t      datacount;      /* client data count */
  80         STAILQ_ENTRY(bounce_page) links;
  81 };
  82
  83 int busdma_swi_pending;
  84
  85 static STAILQ_HEAD(bp_list, bounce_page) bounce_page_list;
  86 static int free_bpages;
  87 static int reserved_bpages;
  88 static int active_bpages;
  89 static int total_bpages;
  90 static bus_addr_t bounce_lowaddr = BUS_SPACE_MAXADDR;
  91
  92 struct bus_dmamap {
  93         struct bp_list  bpages;
  94         int             pagesneeded;
  95         int             pagesreserved;
  96         bus_dma_tag_t   dmat;
  97         void            *buf;           /* unmapped buffer pointer */
  98         bus_size_t      buflen;         /* unmapped buffer length */
  99         bus_dmamap_callback_t *callback;
 100         void            *callback_arg;
 101         STAILQ_ENTRY(bus_dmamap) links;
 102 };
 103
 104 static STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
 105 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
 106 static struct bus_dmamap nobounce_dmamap;
 107
 108 static int              alloc_bounce_pages(bus_dma_tag_t, u_int);
 109 static int              reserve_bounce_pages(bus_dma_tag_t, bus_dmamap_t, int);
 110 static bus_addr_t       add_bounce_page(bus_dma_tag_t, bus_dmamap_t,
 111                             vm_offset_t, bus_size_t);
 112 static void             free_bounce_page(bus_dma_tag_t, struct bounce_page *);
 113
 114 SYSCTL_NODE(_hw, OID_AUTO, busdma, CTLFLAG_RD, 0, "Busdma parameters");
 115 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
 116            "Total bounce pages");
 117
 118 static __inline int
 119 run_filter(bus_dma_tag_t dmat, bus_addr_t paddr)
 120 {
 121         int retval;
 122
 123         retval = 0;
 124         do {
 125                 if (paddr > dmat->lowaddr
 126                  && paddr <= dmat->highaddr
 127                  && (dmat->filter == NULL
 128                   || (*dmat->filter)(dmat->filterarg, paddr) != 0))
 129                         retval = 1;
 130
 131                 dmat = dmat->parent;
 132         } while (retval == 0 && dmat != NULL);
 133         return (retval);
 134 }
 135
 136 /*
 137  * Allocate a device specific dma_tag.
 138  */
 139 int
 140 bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
 141                    bus_size_t boundary, bus_addr_t lowaddr,
 142                    bus_addr_t highaddr, bus_dma_filter_t *filter,
 143                    void *filterarg, bus_size_t maxsize, int nsegments,
 144                    bus_size_t maxsegsz, int flags, bus_dma_tag_t *dmat)
 145 {
 146         bus_dma_tag_t newtag;
 147         int error = 0;
 148
 149         if (alignment == 0)
 150                 alignment = 1;
 151
 152         /* Return a NULL tag on failure */
 153         *dmat = NULL;
 154
 155         newtag = kmalloc(sizeof(*newtag), M_DEVBUF, M_INTWAIT);
 156
 157         newtag->parent = parent;
 158         newtag->alignment = alignment;
 159         newtag->boundary = boundary;
 160         newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1);
 161         newtag->highaddr = trunc_page((vm_paddr_t)highaddr) + (PAGE_SIZE - 1);
 162         newtag->filter = filter;
 163         newtag->filterarg = filterarg;
 164         newtag->maxsize = maxsize;
 165         newtag->nsegments = nsegments;
 166         newtag->maxsegsz = maxsegsz;
 167         newtag->flags = flags;
 168         newtag->ref_count = 1; /* Count ourself */
 169         newtag->map_count = 0;
 170         newtag->segments = NULL;
 171
 172         /* Take into account any restrictions imposed by our parent tag */
 173         if (parent != NULL) {
 174                 newtag->lowaddr = MIN(parent->lowaddr, newtag->lowaddr);
 175                 newtag->highaddr = MAX(parent->highaddr, newtag->highaddr);
 176
 177                 if (newtag->boundary == 0) {
 178                         newtag->boundary = parent->boundary;
 179                 } else if (parent->boundary != 0) {
 180                         newtag->boundary = MIN(parent->boundary,
 181                                                newtag->boundary);
 182                 }
 183
 184 #ifdef notyet
 185                 newtag->alignment = MAX(parent->alignment, newtag->alignment);
 186 #endif
 187
 188                 if (newtag->filter == NULL) {
 189                         /*
 190                          * Short circuit looking at our parent directly
 191                          * since we have encapsulated all of its information
 192                          */
 193                         newtag->filter = parent->filter;
 194                         newtag->filterarg = parent->filterarg;
 195                         newtag->parent = parent->parent;
 196                 }
 197                 if (newtag->parent != NULL)
 198                         parent->ref_count++;
 199         }
 200
 201         if (newtag->lowaddr < ptoa(Maxmem))
 202                 newtag->flags |= BUS_DMA_COULD_BOUNCE;
 203
 204         if ((newtag->flags & BUS_DMA_COULD_BOUNCE) &&
 205             (flags & BUS_DMA_ALLOCNOW) != 0) {
 206                 /* Must bounce */
 207
 208                 if (lowaddr > bounce_lowaddr) {
 209                         /*
 210                          * Go through the pool and kill any pages
 211                          * that don't reside below lowaddr.
 212                          */
 213                         panic("bus_dma_tag_create: page reallocation "
 214                               "not implemented");
 215                 }
 216                 if (ptoa(total_bpages) < maxsize) {
 217                         int pages;
 218
 219                         pages = atop(maxsize) - total_bpages;
 220
 221                         /* Add pages to our bounce pool */
 222                         if (alloc_bounce_pages(newtag, pages) < pages)
 223                                 error = ENOMEM;
 224                 }
 225                 /* Performed initial allocation */
 226                 newtag->flags |= BUS_DMA_MIN_ALLOC_COMP;
 227         }
 228
 229         if (error != 0) {
 230                 kfree(newtag, M_DEVBUF);
 231         } else {
 232                 *dmat = newtag;
 233         }
 234         return (error);
 235 }
 236
 237 int
 238 bus_dma_tag_destroy(bus_dma_tag_t dmat)
 239 {
 240         if (dmat != NULL) {
 241                 if (dmat->map_count != 0)
 242                         return (EBUSY);
 243
 244                 while (dmat != NULL) {
 245                         bus_dma_tag_t parent;
 246
 247                         parent = dmat->parent;
 248                         dmat->ref_count--;
 249                         if (dmat->ref_count == 0) {
 250                                 if (dmat->segments != NULL)
 251                                         kfree(dmat->segments, M_DEVBUF);
 252                                 kfree(dmat, M_DEVBUF);
 253                                 /*
 254                                  * Last reference count, so
 255                                  * release our reference
 256                                  * count on our parent.
 257                                  */
 258                                 dmat = parent;
 259                         } else
 260                                 dmat = NULL;
 261                 }
 262         }
 263         return (0);
 264 }
 265
 266 /*
 267  * Allocate a handle for mapping from kva/uva/physical
 268  * address space into bus device space.
 269  */
 270 int
 271 bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
 272 {
 273         int error;
 274
 275         error = 0;
 276
 277         if (dmat->segments == NULL) {
 278                 KKASSERT(dmat->nsegments && dmat->nsegments < 16384);
 279                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 280                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 281         }
 282
 283         if (dmat->flags & BUS_DMA_COULD_BOUNCE) {
 284                 /* Must bounce */
 285                 int maxpages;
 286
 287                 *mapp = kmalloc(sizeof(**mapp), M_DEVBUF, M_INTWAIT | M_ZERO);
 288
 289                 /* Initialize the new map */
 290                 STAILQ_INIT(&((*mapp)->bpages));
 291                 /*
 292                  * Attempt to add pages to our pool on a per-instance
 293                  * basis up to a sane limit.
 294                  */
 295                 maxpages = MIN(MAX_BPAGES, Maxmem - atop(dmat->lowaddr));
 296                 if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0
 297                  || (dmat->map_count > 0
 298                   && total_bpages < maxpages)) {
 299                         int pages;
 300
 301                         if (dmat->lowaddr > bounce_lowaddr) {
 302                                 /*
 303                                  * Go through the pool and kill any pages
 304                                  * that don't reside below lowaddr.
 305                                  */
 306                                 panic("bus_dmamap_create: page reallocation "
 307                                       "not implemented");
 308                         }
 309
 310                         pages = MAX(atop(dmat->maxsize), 1);
 311                         pages = MIN(maxpages - total_bpages, pages);
 312                         pages = MAX(pages, 1);
 313                         if (alloc_bounce_pages(dmat, pages) < pages)
 314                                 error = ENOMEM;
 315
 316                         if ((dmat->flags & BUS_DMA_MIN_ALLOC_COMP) == 0) {
 317                                 if (error == 0)
 318                                         dmat->flags |= BUS_DMA_MIN_ALLOC_COMP;
 319                         } else {
 320                                 error = 0;
 321                         }
 322                 }
 323         } else {
 324                 *mapp = NULL;
 325         }
 326         if (error == 0)
 327                 dmat->map_count++;
 328         return (error);
 329 }
 330
 331 /*
 332  * Destroy a handle for mapping from kva/uva/physical
 333  * address space into bus device space.
 334  */
 335 int
 336 bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
 337 {
 338         if (map != NULL) {
 339                 if (STAILQ_FIRST(&map->bpages) != NULL)
 340                         return (EBUSY);
 341                 kfree(map, M_DEVBUF);
 342         }
 343         dmat->map_count--;
 344         return (0);
 345 }
 346
 347 /*
 348  * Allocate a piece of memory that can be efficiently mapped into
 349  * bus device space based on the constraints lited in the dma tag.
 350  *
 351  * mapp is degenerate.  By definition this allocation should not require
 352  * bounce buffers so do not allocate a dma map.
 353  */
 354 int
 355 bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
 356                  bus_dmamap_t *mapp)
 357 {
 358         int mflags;
 359
 360         /* If we succeed, no mapping/bouncing will be required */
 361         *mapp = NULL;
 362
 363         if (dmat->segments == NULL) {
 364                 KKASSERT(dmat->nsegments < 16384);
 365                 dmat->segments = kmalloc(sizeof(bus_dma_segment_t) *
 366                                         dmat->nsegments, M_DEVBUF, M_INTWAIT);
 367         }
 368
 369         if (flags & BUS_DMA_NOWAIT)
 370                 mflags = M_NOWAIT;
 371         else
 372                 mflags = M_WAITOK;
 373         if (flags & BUS_DMA_ZERO)
 374                 mflags |= M_ZERO;
 375
 376         if ((dmat->maxsize <= PAGE_SIZE) &&
 377             dmat->lowaddr >= ptoa(Maxmem)) {
 378                 *vaddr = kmalloc(dmat->maxsize, M_DEVBUF, mflags);
 379                 /*
 380                  * XXX Check whether the allocation crossed a page boundary
 381                  * and retry with power-of-2 alignment in that case.
 382                  */
 383                 if ((((intptr_t)*vaddr) & PAGE_MASK) !=
 384                     (((intptr_t)*vaddr + dmat->maxsize) & PAGE_MASK)) {
 385                         size_t size;
 386
 387                         kfree(*vaddr, M_DEVBUF);
 388                         /* XXX check for overflow? */
 389                         for (size = 1; size <= dmat->maxsize; size <<= 1)
 390                                 ;
 391                         *vaddr = kmalloc(size, M_DEVBUF, mflags);
 392                 }
 393         } else {
 394                 /*
 395                  * XXX Use Contigmalloc until it is merged into this facility
 396                  *     and handles multi-seg allocations.  Nobody is doing
 397                  *     multi-seg allocations yet though.
 398                  */
 399                 *vaddr = contigmalloc(dmat->maxsize, M_DEVBUF, mflags,
 400                     0ul, dmat->lowaddr, dmat->alignment, dmat->boundary);
 401         }
 402         if (*vaddr == NULL)
 403                 return (ENOMEM);
 404         return (0);
 405 }
 406
 407 /*
 408  * Free a piece of memory and it's allociated dmamap, that was allocated
 409  * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 410  */
 411 void
 412 bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
 413 {
 414         /*
 415          * dmamem does not need to be bounced, so the map should be
 416          * NULL
 417          */
 418         if (map != NULL)
 419                 panic("bus_dmamem_free: Invalid map freed\n");
 420         if ((dmat->maxsize <= PAGE_SIZE) &&
 421             dmat->lowaddr >= ptoa(Maxmem))
 422                 kfree(vaddr, M_DEVBUF);
 423         else
 424                 contigfree(vaddr, dmat->maxsize, M_DEVBUF);
 425 }
 426
 427 static int
 428 _bus_dmamap_load_buffer2(bus_dma_tag_t dmat,
 429                         bus_dmamap_t map,
 430                         void *buf, bus_size_t buflen,
 431                         struct thread *td,
 432                         int flags,
 433                         vm_paddr_t *lastpaddrp,
 434                         int *segp,
 435                         int first)
 436 {
 437         vm_offset_t vaddr;
 438         vm_paddr_t paddr, nextpaddr;
 439         bus_dma_segment_t *sg;
 440         bus_addr_t bmask;
 441         int seg, error = 0;
 442
 443         if (map == NULL)
 444                 map = &nobounce_dmamap;
 445
 446         /*
 447          * If we are being called during a callback, pagesneeded will
 448          * be non-zero, so we can avoid doing the work twice.
 449          */
 450         if ((dmat->flags & BUS_DMA_COULD_BOUNCE) &&
 451             map != &nobounce_dmamap && map->pagesneeded == 0) {
 452                 vm_offset_t vendaddr;
 453
 454                 /*
 455                  * Count the number of bounce pages
 456                  * needed in order to complete this transfer
 457                  */
 458                 vaddr = (vm_offset_t)buf;
 459                 vendaddr = (vm_offset_t)buf + buflen;
 460
 461                 while (vaddr < vendaddr) {
 462                         paddr = pmap_kextract(vaddr);
 463                         if (run_filter(dmat, paddr) != 0)
 464                                 map->pagesneeded++;
 465                         vaddr += (PAGE_SIZE - ((vm_offset_t)vaddr & PAGE_MASK));
 466                 }
 467         }
 468
 469         /* Reserve Necessary Bounce Pages */
 470         if (map->pagesneeded != 0) {
 471                 crit_enter();
 472                 if (flags & BUS_DMA_NOWAIT) {
 473                         if (reserve_bounce_pages(dmat, map, 0) != 0) {
 474                                 crit_exit();
 475                                 return (ENOMEM);
 476                         }
 477                 } else {
 478                         if (reserve_bounce_pages(dmat, map, 1) != 0) {
 479                                 /* Queue us for resources */
 480                                 map->dmat = dmat;
 481                                 map->buf = buf;
 482                                 map->buflen = buflen;
 483
 484                                 STAILQ_INSERT_TAIL(&bounce_map_waitinglist,
 485                                                    map, links);
 486                                 crit_exit();
 487
 488                                 return (EINPROGRESS);
 489                         }
 490                 }
 491                 crit_exit();
 492         }
 493
 494         KKASSERT(*segp >= 1);
 495         seg = *segp;
 496         sg = &dmat->segments[seg - 1];
 497
 498         vaddr = (vm_offset_t)buf;
 499         nextpaddr = *lastpaddrp;
 500         bmask = ~(dmat->boundary - 1);  /* note: will be 0 if boundary is 0 */
 501
 502         /* force at least one segment */
 503         do {
 504                 bus_size_t size;
 505
 506                 /*
 507                  * Per-page main loop
 508                  */
 509                 paddr = pmap_kextract(vaddr);
 510                 size = PAGE_SIZE - (paddr & PAGE_MASK);
 511                 if (size > buflen)
 512                         size = buflen;
 513                 if (map->pagesneeded != 0 && run_filter(dmat, paddr)) {
 514                         /*
 515                          * note: this paddr has the same in-page offset
 516                          * as vaddr and thus the paddr above, so the
 517                          * size does not have to be recalculated
 518                          */
 519                         paddr = add_bounce_page(dmat, map, vaddr, size);
 520                 }
 521
 522                 /*
 523                  * Fill in the bus_dma_segment
 524                  */
 525                 if (first) {
 526                         sg->ds_addr = paddr;
 527                         sg->ds_len = size;
 528                         first = 0;
 529                 } else if (paddr == nextpaddr) {
 530                         sg->ds_len += size;
 531                 } else {
 532                         sg++;
 533                         seg++;
 534                         if (seg > dmat->nsegments)
 535                                 break;
 536                         sg->ds_addr = paddr;
 537                         sg->ds_len = size;
 538                 }
 539                 nextpaddr = paddr + size;
 540
 541                 /*
 542                  * Handle maxsegsz and boundary issues with a nested loop
 543                  */
 544                 for (;;) {
 545                         bus_size_t tmpsize;
 546
 547                         /*
 548                          * Limit to the boundary and maximum segment size
 549                          */
 550                         if (((nextpaddr - 1) ^ sg->ds_addr) & bmask) {
 551                                 tmpsize = dmat->boundary -
 552                                           (sg->ds_addr & ~bmask);
 553                                 if (tmpsize > dmat->maxsegsz)
 554                                         tmpsize = dmat->maxsegsz;
 555                                 KKASSERT(tmpsize < sg->ds_len);
 556                         } else if (sg->ds_len > dmat->maxsegsz) {
 557                                 tmpsize = dmat->maxsegsz;
 558                         } else {
 559                                 break;
 560                         }
 561
 562                         /*
 563                          * Futz, split the data into a new segment.
 564                          */
 565                         if (seg >= dmat->nsegments)
 566                                 goto fail;
 567                         sg[1].ds_len = sg[0].ds_len - tmpsize;
 568                         sg[1].ds_addr = sg[0].ds_addr + tmpsize;
 569                         sg[0].ds_len = tmpsize;
 570                         sg++;
 571                         seg++;
 572                 }
 573
 574                 /*
 575                  * Adjust for loop
 576                  */
 577                 buflen -= size;
 578                 vaddr += size;
 579         } while (buflen > 0);
 580 fail:
 581         if (buflen != 0) {
 582                 kprintf("bus_dmamap_load: Too many segs! buf_len = 0x%lx\n",
 583                        (u_long)buflen);
 584                 error = EFBIG;
 585         }
 586
 587         *segp = seg;
 588         *lastpaddrp = nextpaddr;
 589
 590         return error;
 591 }
 592
 593 /*
 594  * Map the buffer buf into bus space using the dmamap map.
 595  */
 596 int
 597 bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
 598                 bus_size_t buflen, bus_dmamap_callback_t *callback,
 599                 void *callback_arg, int flags)
 600 {
 601         vm_paddr_t lastaddr = 0;
 602         int error, nsegs = 1;
 603
 604         if (map != NULL) {
 605                 /*
 606                  * XXX
 607                  * Follow old semantics.  Once all of the callers are fixed,
 608                  * we should get rid of these internal flag "adjustment".
 609                  */
 610                 flags &= ~BUS_DMA_NOWAIT;
 611                 flags |= BUS_DMA_WAITOK;
 612
 613                 map->callback = callback;
 614                 map->callback_arg = callback_arg;
 615         }
 616
 617         error = _bus_dmamap_load_buffer2(dmat, map,
 618                         buf, buflen, NULL, flags, &lastaddr, &nsegs, 1);
 619         if (error == EINPROGRESS)
 620                 return error;
 621
 622         callback(callback_arg, dmat->segments, nsegs, error);
 623         return 0;
 624 }
 625
 626 /*
 627  * Utility function to load a linear buffer.  lastaddrp holds state
 628  * between invocations (for multiple-buffer loads).  segp contains
 629  * the starting segment on entrace, and the ending segment on exit.
 630  * first indicates if this is the first invocation of this function.
 631  */
 632 static int
 633 _bus_dmamap_load_buffer(bus_dma_tag_t dmat,
 634                         void *buf, bus_size_t buflen,
 635                         struct thread *td,
 636                         int flags,
 637                         vm_offset_t *lastaddrp,
 638                         int *segp,
 639                         int first)
 640 {
 641         bus_dma_segment_t *segs;
 642         bus_size_t sgsize;
 643         bus_addr_t curaddr, lastaddr, baddr, bmask;
 644         vm_offset_t vaddr = (vm_offset_t)buf;
 645         int seg;
 646         pmap_t pmap;
 647
 648         if (td->td_proc != NULL)
 649                 pmap = vmspace_pmap(td->td_proc->p_vmspace);
 650         else
 651                 pmap = NULL;
 652
 653         segs = dmat->segments;
 654         lastaddr = *lastaddrp;
 655         bmask  = ~(dmat->boundary - 1);
 656
 657         for (seg = *segp; buflen > 0 ; ) {
 658                 /*
 659                  * Get the physical address for this segment.
 660                  */
 661                 if (pmap)
 662                         curaddr = pmap_extract(pmap, vaddr);
 663                 else
 664                         curaddr = pmap_kextract(vaddr);
 665
 666                 /*
 667                  * Compute the segment size, and adjust counts.
 668                  */
 669                 sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
 670                 if (buflen < sgsize)
 671                         sgsize = buflen;
 672
 673                 /*
 674                  * Make sure we don't cross any boundaries.
 675                  */
 676                 if (dmat->boundary > 0) {
 677                         baddr = (curaddr + dmat->boundary) & bmask;
 678                         if (sgsize > (baddr - curaddr))
 679                                 sgsize = (baddr - curaddr);
 680                 }
 681
 682                 /*
 683                  * Insert chunk into a segment, coalescing with
 684                  * previous segment if possible.
 685                  */
 686                 if (first) {
 687                         segs[seg].ds_addr = curaddr;
 688                         segs[seg].ds_len = sgsize;
 689                         first = 0;
 690                 } else {
 691                         if (curaddr == lastaddr &&
 692                             (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
 693                             (dmat->boundary == 0 ||
 694                              (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
 695                                 segs[seg].ds_len += sgsize;
 696                         else {
 697                                 if (++seg >= dmat->nsegments)
 698                                         break;
 699                                 segs[seg].ds_addr = curaddr;
 700                                 segs[seg].ds_len = sgsize;
 701                         }
 702                 }
 703
 704                 lastaddr = curaddr + sgsize;
 705                 vaddr += sgsize;
 706                 buflen -= sgsize;
 707         }
 708
 709         *segp = seg;
 710         *lastaddrp = lastaddr;
 711
 712         /*
 713          * Did we fit?
 714          */
 715         return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
 716 }
 717
 718 /*
 719  * Like _bus_dmamap_load(), but for mbufs.
 720  */
 721 int
 722 bus_dmamap_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map,
 723                      struct mbuf *m0,
 724                      bus_dmamap_callback2_t *callback, void *callback_arg,
 725                      int flags)
 726 {
 727         int nsegs, error;
 728
 729         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 730                 ("bus_dmamap_load_mbuf: No support for bounce pages!"));
 731         KASSERT(m0->m_flags & M_PKTHDR,
 732                 ("bus_dmamap_load_mbuf: no packet header"));
 733
 734         nsegs = 0;
 735         error = 0;
 736         if (m0->m_pkthdr.len <= dmat->maxsize) {
 737                 int first = 1;
 738                 vm_offset_t lastaddr = 0;
 739                 struct mbuf *m;
 740
 741                 for (m = m0; m != NULL && error == 0; m = m->m_next) {
 742                         if ( m->m_len == 0 )
 743                                 continue;
 744                         error = _bus_dmamap_load_buffer(dmat,
 745                                         m->m_data, m->m_len,
 746                                         curthread, flags, &lastaddr,
 747                                         &nsegs, first);
 748                         first = 0;
 749                 }
 750         } else {
 751                 error = EINVAL;
 752         }
 753
 754         if (error) {
 755                 /* force "no valid mappings" in callback */
 756                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 757         } else {
 758                 (*callback)(callback_arg, dmat->segments,
 759                             nsegs+1, m0->m_pkthdr.len, error);
 760         }
 761         return (error);
 762 }
 763
 764 /*
 765  * Like _bus_dmamap_load(), but for uios.
 766  */
 767 int
 768 bus_dmamap_load_uio(bus_dma_tag_t dmat, bus_dmamap_t map,
 769                     struct uio *uio,
 770                     bus_dmamap_callback2_t *callback, void *callback_arg,
 771                     int flags)
 772 {
 773         vm_offset_t lastaddr;
 774         int nsegs, error, first, i;
 775         bus_size_t resid;
 776         struct iovec *iov;
 777         struct thread *td = NULL;
 778
 779         KASSERT(dmat->lowaddr >= ptoa(Maxmem) || map != NULL,
 780                 ("bus_dmamap_load_uio: No support for bounce pages!"));
 781
 782         resid = uio->uio_resid;
 783         iov = uio->uio_iov;
 784
 785         if (uio->uio_segflg == UIO_USERSPACE) {
 786                 td = uio->uio_td;
 787                 KASSERT(td != NULL && td->td_proc != NULL,
 788                         ("bus_dmamap_load_uio: USERSPACE but no proc"));
 789         }
 790
 791         nsegs = 0;
 792         error = 0;
 793         first = 1;
 794         for (i = 0; i < uio->uio_iovcnt && resid != 0 && !error; i++) {
 795                 /*
 796                  * Now at the first iovec to load.  Load each iovec
 797                  * until we have exhausted the residual count.
 798                  */
 799                 bus_size_t minlen =
 800                         resid < iov[i].iov_len ? resid : iov[i].iov_len;
 801                 caddr_t addr = (caddr_t) iov[i].iov_base;
 802
 803                 error = _bus_dmamap_load_buffer(dmat,
 804                                 addr, minlen,
 805                                 td, flags, &lastaddr, &nsegs, first);
 806                 first = 0;
 807
 808                 resid -= minlen;
 809         }
 810
 811         if (error) {
 812                 /* force "no valid mappings" in callback */
 813                 (*callback)(callback_arg, dmat->segments, 0, 0, error);
 814         } else {
 815                 (*callback)(callback_arg, dmat->segments,
 816                             nsegs+1, uio->uio_resid, error);
 817         }
 818         return (error);
 819 }
 820
 821 /*
 822  * Release the mapping held by map.
 823  */
 824 void
 825 _bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
 826 {
 827         struct bounce_page *bpage;
 828
 829         while ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 830                 STAILQ_REMOVE_HEAD(&map->bpages, links);
 831                 free_bounce_page(dmat, bpage);
 832         }
 833 }
 834
 835 void
 836 _bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
 837 {
 838         struct bounce_page *bpage;
 839
 840         if ((bpage = STAILQ_FIRST(&map->bpages)) != NULL) {
 841                 /*
 842                  * Handle data bouncing.  We might also
 843                  * want to add support for invalidating
 844                  * the caches on broken hardware
 845                  */
 846                 switch (op) {
 847                 case BUS_DMASYNC_PREWRITE:
 848                         while (bpage != NULL) {
 849                                 bcopy((void *)bpage->datavaddr,
 850                                       (void *)bpage->vaddr,
 851                                       bpage->datacount);
 852                                 bpage = STAILQ_NEXT(bpage, links);
 853                         }
 854                         break;
 855
 856                 case BUS_DMASYNC_POSTREAD:
 857                         while (bpage != NULL) {
 858                                 bcopy((void *)bpage->vaddr,
 859                                       (void *)bpage->datavaddr,
 860                                       bpage->datacount);
 861                                 bpage = STAILQ_NEXT(bpage, links);
 862                         }
 863                         break;
 864
 865                 case BUS_DMASYNC_PREREAD:
 866                 case BUS_DMASYNC_POSTWRITE:
 867                         /* No-ops */
 868                         break;
 869                 }
 870         }
 871 }
 872
 873 static int
 874 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
 875 {
 876         int count;
 877
 878         count = 0;
 879         if (total_bpages == 0) {
 880                 STAILQ_INIT(&bounce_page_list);
 881                 STAILQ_INIT(&bounce_map_waitinglist);
 882                 STAILQ_INIT(&bounce_map_callbacklist);
 883         }
 884
 885         while (numpages > 0) {
 886                 struct bounce_page *bpage;
 887
 888                 bpage = kmalloc(sizeof(*bpage), M_DEVBUF, M_INTWAIT | M_ZERO);
 889
 890                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_DEVBUF,
 891                                                          M_NOWAIT, 0ul,
 892                                                          dmat->lowaddr,
 893                                                          PAGE_SIZE,
 894                                                          0);
 895                 if (bpage->vaddr == 0) {
 896                         kfree(bpage, M_DEVBUF);
 897                         break;
 898                 }
 899                 bpage->busaddr = pmap_kextract(bpage->vaddr);
 900                 crit_enter();
 901                 STAILQ_INSERT_TAIL(&bounce_page_list, bpage, links);
 902                 total_bpages++;
 903                 free_bpages++;
 904                 crit_exit();
 905                 count++;
 906                 numpages--;
 907         }
 908         return (count);
 909 }
 910
 911 static int
 912 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
 913 {
 914         int pages;
 915
 916         pages = MIN(free_bpages, map->pagesneeded - map->pagesreserved);
 917         if (!commit && map->pagesneeded > (map->pagesreserved + pages))
 918                 return (map->pagesneeded - (map->pagesreserved + pages));
 919         free_bpages -= pages;
 920         reserved_bpages += pages;
 921         map->pagesreserved += pages;
 922         pages = map->pagesneeded - map->pagesreserved;
 923
 924         return (pages);
 925 }
 926
 927 static bus_addr_t
 928 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 929                 bus_size_t size)
 930 {
 931         struct bounce_page *bpage;
 932
 933         if (map->pagesneeded == 0)
 934                 panic("add_bounce_page: map doesn't need any pages");
 935         map->pagesneeded--;
 936
 937         if (map->pagesreserved == 0)
 938                 panic("add_bounce_page: map doesn't need any pages");
 939         map->pagesreserved--;
 940
 941         crit_enter();
 942         bpage = STAILQ_FIRST(&bounce_page_list);
 943         if (bpage == NULL)
 944                 panic("add_bounce_page: free page list is empty");
 945
 946         STAILQ_REMOVE_HEAD(&bounce_page_list, links);
 947         reserved_bpages--;
 948         active_bpages++;
 949         crit_exit();
 950
 951         bpage->datavaddr = vaddr;
 952         bpage->datacount = size;
 953         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 954         return (bpage->busaddr);
 955 }
 956
 957 static void
 958 free_bounce_page(bus_dma_tag_t dmat, struct bounce_page *bpage)
 959 {
 960         struct bus_dmamap *map;
 961
 962         bpage->datavaddr = 0;
 963         bpage->datacount = 0;
 964
 965         crit_enter();
 966         STAILQ_INSERT_HEAD(&bounce_page_list, bpage, links);
 967         free_bpages++;
 968         active_bpages--;
 969         if ((map = STAILQ_FIRST(&bounce_map_waitinglist)) != NULL) {
 970                 if (reserve_bounce_pages(map->dmat, map, 1) == 0) {
 971                         STAILQ_REMOVE_HEAD(&bounce_map_waitinglist, links);
 972                         STAILQ_INSERT_TAIL(&bounce_map_callbacklist,
 973                                            map, links);
 974                         busdma_swi_pending = 1;
 975                         setsoftvm();
 976                 }
 977         }
 978         crit_exit();
 979 }
 980
 981 void
 982 busdma_swi(void)
 983 {
 984         struct bus_dmamap *map;
 985
 986         crit_enter();
 987         while ((map = STAILQ_FIRST(&bounce_map_callbacklist)) != NULL) {
 988                 STAILQ_REMOVE_HEAD(&bounce_map_callbacklist, links);
 989                 crit_exit();
 990                 bus_dmamap_load(map->dmat, map, map->buf, map->buflen,
 991                                 map->callback, map->callback_arg, /*flags*/0);
 992                 crit_enter();
 993         }
 994         crit_exit();
 995 }