Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_busdma_bounce.c
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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 }
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