sys/kern/subr_busdma_bounce.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 1997, 1998 Justin T. Gibbs.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions, and the following disclaimer,
  12  *    without modification, immediately at the beginning of the file.
  13  * 2. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
  20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 /*
  30  * Common code for managing bounce pages for bus_dma backends.  As
  31  * this code currently assumes it can access internal members of
  32  * opaque types like bus_dma_tag_t and bus_dmamap it is #include'd in
  33  * backends rather than being compiled standalone.
  34  *
  35  * Prerequisites:
  36  *
  37  * - M_BUSDMA malloc type
  38  * - struct bus_dmamap
  39  * - hw_busdma SYSCTL_NODE
  40  * - macros to access the following fields of bus_dma_tag_t:
  41  *   - dmat_alignment()
  42  *   - dmat_flags()
  43  *   - dmat_lowaddr()
  44  *   - dmat_lockfunc()
  45  *   - dmat_lockarg()
  46  */
  47
  48 #include <sys/kthread.h>
  49 #include <sys/sched.h>
  50
  51 struct bounce_page {
  52         vm_offset_t     vaddr;          /* kva of bounce buffer */
  53         bus_addr_t      busaddr;        /* Physical address */
  54         vm_offset_t     datavaddr;      /* kva of client data */
  55 #if defined(__amd64__) || defined(__i386__)
  56         vm_page_t       datapage[2];    /* physical page(s) of client data */
  57 #else
  58         vm_page_t       datapage;       /* physical page of client data */
  59 #endif
  60         vm_offset_t     dataoffs;       /* page offset of client data */
  61         bus_size_t      datacount;      /* client data count */
  62         STAILQ_ENTRY(bounce_page) links;
  63 };
  64
  65 struct bounce_zone {
  66         STAILQ_ENTRY(bounce_zone) links;
  67         STAILQ_HEAD(, bounce_page) bounce_page_list;
  68         STAILQ_HEAD(, bus_dmamap) bounce_map_waitinglist;
  69         int             total_bpages;
  70         int             free_bpages;
  71         int             reserved_bpages;
  72         int             active_bpages;
  73         int             total_bounced;
  74         int             total_deferred;
  75         int             map_count;
  76 #ifdef dmat_domain
  77         int             domain;
  78 #endif
  79         bus_size_t      alignment;
  80         bus_addr_t      lowaddr;
  81         char            zoneid[8];
  82         char            lowaddrid[20];
  83         struct sysctl_ctx_list sysctl_tree;
  84         struct sysctl_oid *sysctl_tree_top;
  85 };
  86
  87 static struct mtx bounce_lock;
  88 static int total_bpages;
  89 static int busdma_zonecount;
  90
  91 static STAILQ_HEAD(, bounce_zone) bounce_zone_list;
  92 static STAILQ_HEAD(, bus_dmamap) bounce_map_callbacklist;
  93
  94 static MALLOC_DEFINE(M_BOUNCE, "bounce", "busdma bounce pages");
  95
  96 SYSCTL_INT(_hw_busdma, OID_AUTO, total_bpages, CTLFLAG_RD, &total_bpages, 0,
  97    "Total bounce pages");
  98
  99 static void busdma_thread(void *);
 100 static int reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map,
 101     int commit);
 102
 103 static int
 104 _bus_dmamap_reserve_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int flags)
 105 {
 106         struct bounce_zone *bz;
 107
 108         /* Reserve Necessary Bounce Pages */
 109         mtx_lock(&bounce_lock);
 110         if (flags & BUS_DMA_NOWAIT) {
 111                 if (reserve_bounce_pages(dmat, map, 0) != 0) {
 112                         map->pagesneeded = 0;
 113                         mtx_unlock(&bounce_lock);
 114                         return (ENOMEM);
 115                 }
 116         } else {
 117                 if (reserve_bounce_pages(dmat, map, 1) != 0) {
 118                         /* Queue us for resources */
 119                         bz = dmat->bounce_zone;
 120                         STAILQ_INSERT_TAIL(&bz->bounce_map_waitinglist, map,
 121                             links);
 122                         mtx_unlock(&bounce_lock);
 123                         return (EINPROGRESS);
 124                 }
 125         }
 126         mtx_unlock(&bounce_lock);
 127
 128         return (0);
 129 }
 130
 131 static void
 132 init_bounce_pages(void *dummy __unused)
 133 {
 134
 135         total_bpages = 0;
 136         STAILQ_INIT(&bounce_zone_list);
 137         STAILQ_INIT(&bounce_map_callbacklist);
 138         mtx_init(&bounce_lock, "bounce pages lock", NULL, MTX_DEF);
 139 }
 140 SYSINIT(bpages, SI_SUB_LOCK, SI_ORDER_ANY, init_bounce_pages, NULL);
 141
 142 static struct sysctl_ctx_list *
 143 busdma_sysctl_tree(struct bounce_zone *bz)
 144 {
 145
 146         return (&bz->sysctl_tree);
 147 }
 148
 149 static struct sysctl_oid *
 150 busdma_sysctl_tree_top(struct bounce_zone *bz)
 151 {
 152
 153         return (bz->sysctl_tree_top);
 154 }
 155
 156 static int
 157 alloc_bounce_zone(bus_dma_tag_t dmat)
 158 {
 159         struct bounce_zone *bz;
 160         bool start_thread;
 161
 162         /* Check to see if we already have a suitable zone */
 163         STAILQ_FOREACH(bz, &bounce_zone_list, links) {
 164                 if ((dmat_alignment(dmat) <= bz->alignment) &&
 165 #ifdef dmat_domain
 166                     dmat_domain(dmat) == bz->domain &&
 167 #endif
 168                     (dmat_lowaddr(dmat) >= bz->lowaddr)) {
 169                         dmat->bounce_zone = bz;
 170                         return (0);
 171                 }
 172         }
 173
 174         if ((bz = (struct bounce_zone *)malloc(sizeof(*bz), M_BUSDMA,
 175             M_NOWAIT | M_ZERO)) == NULL)
 176                 return (ENOMEM);
 177
 178         STAILQ_INIT(&bz->bounce_page_list);
 179         STAILQ_INIT(&bz->bounce_map_waitinglist);
 180         bz->free_bpages = 0;
 181         bz->reserved_bpages = 0;
 182         bz->active_bpages = 0;
 183         bz->lowaddr = dmat_lowaddr(dmat);
 184         bz->alignment = MAX(dmat_alignment(dmat), PAGE_SIZE);
 185         bz->map_count = 0;
 186 #ifdef dmat_domain
 187         bz->domain = dmat_domain(dmat);
 188 #endif
 189         snprintf(bz->zoneid, sizeof(bz->zoneid), "zone%d", busdma_zonecount);
 190         busdma_zonecount++;
 191         snprintf(bz->lowaddrid, sizeof(bz->lowaddrid), "%#jx",
 192             (uintmax_t)bz->lowaddr);
 193         start_thread = STAILQ_EMPTY(&bounce_zone_list);
 194         STAILQ_INSERT_TAIL(&bounce_zone_list, bz, links);
 195         dmat->bounce_zone = bz;
 196
 197         sysctl_ctx_init(&bz->sysctl_tree);
 198         bz->sysctl_tree_top = SYSCTL_ADD_NODE(&bz->sysctl_tree,
 199             SYSCTL_STATIC_CHILDREN(_hw_busdma), OID_AUTO, bz->zoneid,
 200             CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");
 201         if (bz->sysctl_tree_top == NULL) {
 202                 sysctl_ctx_free(&bz->sysctl_tree);
 203                 return (0);     /* XXX error code? */
 204         }
 205
 206         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 207             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 208             "total_bpages", CTLFLAG_RD, &bz->total_bpages, 0,
 209             "Total bounce pages");
 210         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 211             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 212             "free_bpages", CTLFLAG_RD, &bz->free_bpages, 0,
 213             "Free bounce pages");
 214         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 215             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 216             "reserved_bpages", CTLFLAG_RD, &bz->reserved_bpages, 0,
 217             "Reserved bounce pages");
 218         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 219             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 220             "active_bpages", CTLFLAG_RD, &bz->active_bpages, 0,
 221             "Active bounce pages");
 222         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 223             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 224             "total_bounced", CTLFLAG_RD, &bz->total_bounced, 0,
 225             "Total bounce requests (pages bounced)");
 226         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 227             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 228             "total_deferred", CTLFLAG_RD, &bz->total_deferred, 0,
 229             "Total bounce requests that were deferred");
 230         SYSCTL_ADD_STRING(busdma_sysctl_tree(bz),
 231             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 232             "lowaddr", CTLFLAG_RD, bz->lowaddrid, 0, "");
 233         SYSCTL_ADD_UAUTO(busdma_sysctl_tree(bz),
 234             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 235             "alignment", CTLFLAG_RD, &bz->alignment, "");
 236 #ifdef dmat_domain
 237         SYSCTL_ADD_INT(busdma_sysctl_tree(bz),
 238             SYSCTL_CHILDREN(busdma_sysctl_tree_top(bz)), OID_AUTO,
 239             "domain", CTLFLAG_RD, &bz->domain, 0,
 240             "memory domain");
 241 #endif
 242
 243         if (start_thread) {
 244                 if (kproc_create(busdma_thread, NULL, NULL, 0, 0, "busdma") !=
 245                     0)
 246                         printf("failed to create busdma thread");
 247         }
 248         return (0);
 249 }
 250
 251 static int
 252 alloc_bounce_pages(bus_dma_tag_t dmat, u_int numpages)
 253 {
 254         struct bounce_zone *bz;
 255         int count;
 256
 257         bz = dmat->bounce_zone;
 258         count = 0;
 259         while (numpages > 0) {
 260                 struct bounce_page *bpage;
 261
 262 #ifdef dmat_domain
 263                 bpage = malloc_domainset(sizeof(*bpage), M_BUSDMA,
 264                     DOMAINSET_PREF(bz->domain), M_NOWAIT | M_ZERO);
 265 #else
 266                 bpage = malloc(sizeof(*bpage), M_BUSDMA, M_NOWAIT | M_ZERO);
 267 #endif
 268
 269                 if (bpage == NULL)
 270                         break;
 271 #ifdef dmat_domain
 272                 bpage->vaddr = (vm_offset_t)contigmalloc_domainset(PAGE_SIZE,
 273                     M_BOUNCE, DOMAINSET_PREF(bz->domain), M_NOWAIT,
 274                     0ul, bz->lowaddr, PAGE_SIZE, 0);
 275 #else
 276                 bpage->vaddr = (vm_offset_t)contigmalloc(PAGE_SIZE, M_BOUNCE,
 277                     M_NOWAIT, 0ul, bz->lowaddr, PAGE_SIZE, 0);
 278 #endif
 279                 if (bpage->vaddr == 0) {
 280                         free(bpage, M_BUSDMA);
 281                         break;
 282                 }
 283                 bpage->busaddr = pmap_kextract(bpage->vaddr);
 284                 mtx_lock(&bounce_lock);
 285                 STAILQ_INSERT_TAIL(&bz->bounce_page_list, bpage, links);
 286                 total_bpages++;
 287                 bz->total_bpages++;
 288                 bz->free_bpages++;
 289                 mtx_unlock(&bounce_lock);
 290                 count++;
 291                 numpages--;
 292         }
 293         return (count);
 294 }
 295
 296 static int
 297 reserve_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map, int commit)
 298 {
 299         struct bounce_zone *bz;
 300         int pages;
 301
 302         mtx_assert(&bounce_lock, MA_OWNED);
 303         bz = dmat->bounce_zone;
 304         pages = MIN(bz->free_bpages, map->pagesneeded - map->pagesreserved);
 305         if (commit == 0 && map->pagesneeded > (map->pagesreserved + pages))
 306                 return (map->pagesneeded - (map->pagesreserved + pages));
 307         bz->free_bpages -= pages;
 308         bz->reserved_bpages += pages;
 309         map->pagesreserved += pages;
 310         pages = map->pagesneeded - map->pagesreserved;
 311
 312         return (pages);
 313 }
 314
 315 #if defined(__amd64__) || defined(__i386__)
 316 static bus_addr_t
 317 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 318     vm_paddr_t addr1, vm_paddr_t addr2, bus_size_t size)
 319 #else
 320 static bus_addr_t
 321 add_bounce_page(bus_dma_tag_t dmat, bus_dmamap_t map, vm_offset_t vaddr,
 322     bus_addr_t addr, bus_size_t size)
 323 #endif
 324 {
 325         struct bounce_zone *bz;
 326         struct bounce_page *bpage;
 327
 328         KASSERT(dmat->bounce_zone != NULL, ("no bounce zone in dma tag"));
 329         KASSERT(map != NULL, ("add_bounce_page: bad map %p", map));
 330 #if defined(__amd64__) || defined(__i386__)
 331         KASSERT(map != &nobounce_dmamap, ("add_bounce_page: bad map %p", map));
 332 #endif
 333 #ifdef __riscv
 334         KASSERT((map->flags & DMAMAP_COULD_BOUNCE) != 0,
 335             ("add_bounce_page: bad map %p", map));
 336 #endif
 337
 338         bz = dmat->bounce_zone;
 339         if (map->pagesneeded == 0)
 340                 panic("add_bounce_page: map doesn't need any pages");
 341         map->pagesneeded--;
 342
 343         if (map->pagesreserved == 0)
 344                 panic("add_bounce_page: map doesn't need any pages");
 345         map->pagesreserved--;
 346
 347         mtx_lock(&bounce_lock);
 348         bpage = STAILQ_FIRST(&bz->bounce_page_list);
 349         if (bpage == NULL)
 350                 panic("add_bounce_page: free page list is empty");
 351
 352         STAILQ_REMOVE_HEAD(&bz->bounce_page_list, links);
 353         bz->reserved_bpages--;
 354         bz->active_bpages++;
 355         mtx_unlock(&bounce_lock);
 356
 357         if (dmat_flags(dmat) & BUS_DMA_KEEP_PG_OFFSET) {
 358                 /* Page offset needs to be preserved. */
 359 #if defined(__amd64__) || defined(__i386__)
 360                 bpage->vaddr |= addr1 & PAGE_MASK;
 361                 bpage->busaddr |= addr1 & PAGE_MASK;
 362                 KASSERT(addr2 == 0,
 363             ("Trying to bounce multiple pages with BUS_DMA_KEEP_PG_OFFSET"));
 364 #else
 365                 bpage->vaddr |= addr & PAGE_MASK;
 366                 bpage->busaddr |= addr & PAGE_MASK;
 367 #endif
 368         }
 369         bpage->datavaddr = vaddr;
 370 #if defined(__amd64__) || defined(__i386__)
 371         bpage->datapage[0] = PHYS_TO_VM_PAGE(addr1);
 372         KASSERT((addr2 & PAGE_MASK) == 0, ("Second page is not aligned"));
 373         bpage->datapage[1] = PHYS_TO_VM_PAGE(addr2);
 374         bpage->dataoffs = addr1 & PAGE_MASK;
 375 #else
 376         bpage->datapage = PHYS_TO_VM_PAGE(addr);
 377         bpage->dataoffs = addr & PAGE_MASK;
 378 #endif
 379         bpage->datacount = size;
 380         STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 381         return (bpage->busaddr);
 382 }
 383
 384 static void
 385 free_bounce_pages(bus_dma_tag_t dmat, bus_dmamap_t map)
 386 {
 387         struct bounce_page *bpage;
 388         struct bounce_zone *bz;
 389         bool schedule_thread;
 390         u_int count;
 391
 392         if (STAILQ_EMPTY(&map->bpages))
 393                 return;
 394
 395         bz = dmat->bounce_zone;
 396         count = 0;
 397         schedule_thread = false;
 398         STAILQ_FOREACH(bpage, &map->bpages, links) {
 399                 bpage->datavaddr = 0;
 400                 bpage->datacount = 0;
 401
 402                 if (dmat_flags(dmat) & BUS_DMA_KEEP_PG_OFFSET) {
 403                         /*
 404                          * Reset the bounce page to start at offset 0.
 405                          * Other uses of this bounce page may need to
 406                          * store a full page of data and/or assume it
 407                          * starts on a page boundary.
 408                          */
 409                         bpage->vaddr &= ~PAGE_MASK;
 410                         bpage->busaddr &= ~PAGE_MASK;
 411                 }
 412                 count++;
 413         }
 414
 415         mtx_lock(&bounce_lock);
 416         STAILQ_CONCAT(&bz->bounce_page_list, &map->bpages);
 417         bz->free_bpages += count;
 418         bz->active_bpages -= count;
 419         while ((map = STAILQ_FIRST(&bz->bounce_map_waitinglist)) != NULL) {
 420                 if (reserve_bounce_pages(map->dmat, map, 1) != 0)
 421                         break;
 422
 423                 STAILQ_REMOVE_HEAD(&bz->bounce_map_waitinglist, links);
 424                 STAILQ_INSERT_TAIL(&bounce_map_callbacklist, map, links);
 425                 bz->total_deferred++;
 426                 schedule_thread = true;
 427         }
 428         mtx_unlock(&bounce_lock);
 429         if (schedule_thread)
 430                 wakeup(&bounce_map_callbacklist);
 431 }
 432
 433 static void
 434 busdma_thread(void *dummy __unused)
 435 {
 436         STAILQ_HEAD(, bus_dmamap) callbacklist;
 437         bus_dma_tag_t dmat;
 438         struct bus_dmamap *map, *nmap;
 439
 440         thread_lock(curthread);
 441         sched_class(curthread, PRI_ITHD);
 442         sched_ithread_prio(curthread, PI_SWI(SWI_BUSDMA));
 443         thread_unlock(curthread);
 444         for (;;) {
 445                 mtx_lock(&bounce_lock);
 446                 while (STAILQ_EMPTY(&bounce_map_callbacklist))
 447                         mtx_sleep(&bounce_map_callbacklist, &bounce_lock, 0,
 448                             "-", 0);
 449                 STAILQ_INIT(&callbacklist);
 450                 STAILQ_CONCAT(&callbacklist, &bounce_map_callbacklist);
 451                 mtx_unlock(&bounce_lock);
 452
 453                 STAILQ_FOREACH_SAFE(map, &callbacklist, links, nmap) {
 454                         dmat = map->dmat;
 455                         dmat_lockfunc(dmat)(dmat_lockfuncarg(dmat),
 456                             BUS_DMA_LOCK);
 457                         bus_dmamap_load_mem(map->dmat, map, &map->mem,
 458                             map->callback, map->callback_arg, BUS_DMA_WAITOK);
 459                         dmat_lockfunc(dmat)(dmat_lockfuncarg(dmat),
 460                             BUS_DMA_UNLOCK);
 461                 }
 462         }
 463 }