1 /* 2 * Copyright 1998 Massachusetts Institute of Technology 3 * 4 * Permission to use, copy, modify, and distribute this software and 5 * its documentation for any purpose and without fee is hereby 6 * granted, provided that both the above copyright notice and this 7 * permission notice appear in all copies, that both the above 8 * copyright notice and this permission notice appear in all 9 * supporting documentation, and that the name of M.I.T. not be used 10 * in advertising or publicity pertaining to distribution of the 11 * software without specific, written prior permission. M.I.T. makes 12 * no representations about the suitability of this software for any 13 * purpose. It is provided "as is" without express or implied 14 * warranty. 15 * 16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS 17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, 18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 32 /* 33 * The kernel resource manager. This code is responsible for keeping track 34 * of hardware resources which are apportioned out to various drivers. 35 * It does not actually assign those resources, and it is not expected 36 * that end-device drivers will call into this code directly. Rather, 37 * the code which implements the buses that those devices are attached to, 38 * and the code which manages CPU resources, will call this code, and the 39 * end-device drivers will make upcalls to that code to actually perform 40 * the allocation. 41 * 42 * There are two sorts of resources managed by this code. The first is 43 * the more familiar array (RMAN_ARRAY) type; resources in this class 44 * consist of a sequence of individually-allocatable objects which have 45 * been numbered in some well-defined order. Most of the resources 46 * are of this type, as it is the most familiar. The second type is 47 * called a gauge (RMAN_GAUGE), and models fungible resources (i.e., 48 * resources in which each instance is indistinguishable from every 49 * other instance). The principal anticipated application of gauges 50 * is in the context of power consumption, where a bus may have a specific 51 * power budget which all attached devices share. RMAN_GAUGE is not 52 * implemented yet. 53 * 54 * For array resources, we make one simplifying assumption: two clients 55 * sharing the same resource must use the same range of indices. That 56 * is to say, sharing of overlapping-but-not-identical regions is not 57 * permitted. 58 */ 59 60 #include <sys/param.h> 61 #include <sys/systm.h> 62 #include <sys/kernel.h> 63 #include <sys/lock.h> 64 #include <sys/malloc.h> 65 #include <sys/mutex.h> 66 #include <sys/bus.h> /* XXX debugging */ 67 #include <machine/bus.h> 68 #include <sys/rman.h> 69 70 #ifdef RMAN_DEBUG 71 #define DPRINTF(params) printf##params 72 #else 73 #define DPRINTF(params) 74 #endif 75 76 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager"); 77 78 struct rman_head rman_head; 79 static struct mtx rman_mtx; /* mutex to protect rman_head */ 80 static int int_rman_activate_resource(struct rman *rm, struct resource *r, 81 struct resource **whohas); 82 static int int_rman_deactivate_resource(struct resource *r); 83 static int int_rman_release_resource(struct rman *rm, struct resource *r); 84 85 int 86 rman_init(struct rman *rm) 87 { 88 static int once; 89 90 if (once == 0) { 91 once = 1; 92 TAILQ_INIT(&rman_head); 93 mtx_init(&rman_mtx, "rman head", MTX_DEF); 94 } 95 96 if (rm->rm_type == RMAN_UNINIT) 97 panic("rman_init"); 98 if (rm->rm_type == RMAN_GAUGE) 99 panic("implement RMAN_GAUGE"); 100 101 TAILQ_INIT(&rm->rm_list); 102 rm->rm_mtx = malloc(sizeof *rm->rm_mtx, M_RMAN, M_NOWAIT | M_ZERO); 103 if (rm->rm_mtx == 0) 104 return ENOMEM; 105 mtx_init(rm->rm_mtx, "rman", MTX_DEF); 106 107 mtx_lock(&rman_mtx); 108 TAILQ_INSERT_TAIL(&rman_head, rm, rm_link); 109 mtx_unlock(&rman_mtx); 110 return 0; 111 } 112 113 /* 114 * NB: this interface is not robust against programming errors which 115 * add multiple copies of the same region. 116 */ 117 int 118 rman_manage_region(struct rman *rm, u_long start, u_long end) 119 { 120 struct resource *r, *s; 121 122 r = malloc(sizeof *r, M_RMAN, M_NOWAIT | M_ZERO); 123 if (r == 0) 124 return ENOMEM; 125 r->r_start = start; 126 r->r_end = end; 127 r->r_rm = rm; 128 129 mtx_lock(rm->rm_mtx); 130 for (s = TAILQ_FIRST(&rm->rm_list); 131 s && s->r_end < r->r_start; 132 s = TAILQ_NEXT(s, r_link)) 133 ; 134 135 if (s == NULL) { 136 TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link); 137 } else { 138 TAILQ_INSERT_BEFORE(s, r, r_link); 139 } 140 141 mtx_unlock(rm->rm_mtx); 142 return 0; 143 } 144 145 int 146 rman_fini(struct rman *rm) 147 { 148 struct resource *r; 149 150 mtx_lock(rm->rm_mtx); 151 TAILQ_FOREACH(r, &rm->rm_list, r_link) { 152 if (r->r_flags & RF_ALLOCATED) { 153 mtx_unlock(rm->rm_mtx); 154 return EBUSY; 155 } 156 } 157 158 /* 159 * There really should only be one of these if we are in this 160 * state and the code is working properly, but it can't hurt. 161 */ 162 while (!TAILQ_EMPTY(&rm->rm_list)) { 163 r = TAILQ_FIRST(&rm->rm_list); 164 TAILQ_REMOVE(&rm->rm_list, r, r_link); 165 free(r, M_RMAN); 166 } 167 mtx_unlock(rm->rm_mtx); 168 mtx_lock(&rman_mtx); 169 TAILQ_REMOVE(&rman_head, rm, rm_link); 170 mtx_unlock(&rman_mtx); 171 mtx_destroy(rm->rm_mtx); 172 free(rm->rm_mtx, M_RMAN); 173 174 return 0; 175 } 176 177 struct resource * 178 rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end, 179 u_long count, u_long bound, u_int flags, 180 struct device *dev) 181 { 182 u_int want_activate; 183 struct resource *r, *s, *rv; 184 u_long rstart, rend, amask, bmask; 185 186 rv = 0; 187 188 DPRINTF(("rman_reserve_resource: <%s> request: [%#lx, %#lx], length " 189 "%#lx, flags %u, device %s\n", rm->rm_descr, start, end, count, 190 flags, dev == NULL ? "<null>" : device_get_nameunit(dev))); 191 want_activate = (flags & RF_ACTIVE); 192 flags &= ~RF_ACTIVE; 193 194 mtx_lock(rm->rm_mtx); 195 196 for (r = TAILQ_FIRST(&rm->rm_list); 197 r && r->r_end < start; 198 r = TAILQ_NEXT(r, r_link)) 199 ; 200 201 if (r == NULL) { 202 DPRINTF(("could not find a region\n")); 203 goto out; 204 } 205 206 amask = (1ul << RF_ALIGNMENT(flags)) - 1; 207 /* If bound is 0, bmask will also be 0 */ 208 bmask = ~(bound - 1); 209 /* 210 * First try to find an acceptable totally-unshared region. 211 */ 212 for (s = r; s; s = TAILQ_NEXT(s, r_link)) { 213 DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end)); 214 if (s->r_start > end) { 215 DPRINTF(("s->r_start (%#lx) > end (%#lx)\n", s->r_start, end)); 216 break; 217 } 218 if (s->r_flags & RF_ALLOCATED) { 219 DPRINTF(("region is allocated\n")); 220 continue; 221 } 222 rstart = ulmax(s->r_start, start); 223 /* 224 * Try to find a region by adjusting to boundary and alignment 225 * until both conditions are satisfied. This is not an optimal 226 * algorithm, but in most cases it isn't really bad, either. 227 */ 228 do { 229 rstart = (rstart + amask) & ~amask; 230 if (((rstart ^ (rstart + count)) & bmask) != 0) 231 rstart += bound - (rstart & ~bmask); 232 } while ((rstart & amask) != 0 && rstart < end && 233 rstart < s->r_end); 234 rend = ulmin(s->r_end, ulmax(rstart + count, end)); 235 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n", 236 rstart, rend, (rend - rstart + 1), count)); 237 238 if ((rend - rstart + 1) >= count) { 239 DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n", 240 rend, rstart, (rend - rstart + 1))); 241 if ((s->r_end - s->r_start + 1) == count) { 242 DPRINTF(("candidate region is entire chunk\n")); 243 rv = s; 244 rv->r_flags |= RF_ALLOCATED | flags; 245 rv->r_dev = dev; 246 goto out; 247 } 248 249 /* 250 * If s->r_start < rstart and 251 * s->r_end > rstart + count - 1, then 252 * we need to split the region into three pieces 253 * (the middle one will get returned to the user). 254 * Otherwise, we are allocating at either the 255 * beginning or the end of s, so we only need to 256 * split it in two. The first case requires 257 * two new allocations; the second requires but one. 258 */ 259 rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT | M_ZERO); 260 if (rv == 0) 261 goto out; 262 rv->r_start = rstart; 263 rv->r_end = rstart + count - 1; 264 rv->r_flags = flags | RF_ALLOCATED; 265 rv->r_dev = dev; 266 rv->r_rm = rm; 267 268 if (s->r_start < rv->r_start && s->r_end > rv->r_end) { 269 DPRINTF(("splitting region in three parts: " 270 "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n", 271 s->r_start, rv->r_start - 1, 272 rv->r_start, rv->r_end, 273 rv->r_end + 1, s->r_end)); 274 /* 275 * We are allocating in the middle. 276 */ 277 r = malloc(sizeof *r, M_RMAN, M_NOWAIT|M_ZERO); 278 if (r == 0) { 279 free(rv, M_RMAN); 280 rv = 0; 281 goto out; 282 } 283 r->r_start = rv->r_end + 1; 284 r->r_end = s->r_end; 285 r->r_flags = s->r_flags; 286 r->r_rm = rm; 287 s->r_end = rv->r_start - 1; 288 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv, 289 r_link); 290 TAILQ_INSERT_AFTER(&rm->rm_list, rv, r, 291 r_link); 292 } else if (s->r_start == rv->r_start) { 293 DPRINTF(("allocating from the beginning\n")); 294 /* 295 * We are allocating at the beginning. 296 */ 297 s->r_start = rv->r_end + 1; 298 TAILQ_INSERT_BEFORE(s, rv, r_link); 299 } else { 300 DPRINTF(("allocating at the end\n")); 301 /* 302 * We are allocating at the end. 303 */ 304 s->r_end = rv->r_start - 1; 305 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv, 306 r_link); 307 } 308 goto out; 309 } 310 } 311 312 /* 313 * Now find an acceptable shared region, if the client's requirements 314 * allow sharing. By our implementation restriction, a candidate 315 * region must match exactly by both size and sharing type in order 316 * to be considered compatible with the client's request. (The 317 * former restriction could probably be lifted without too much 318 * additional work, but this does not seem warranted.) 319 */ 320 DPRINTF(("no unshared regions found\n")); 321 if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0) 322 goto out; 323 324 for (s = r; s; s = TAILQ_NEXT(s, r_link)) { 325 if (s->r_start > end) 326 break; 327 if ((s->r_flags & flags) != flags) 328 continue; 329 rstart = ulmax(s->r_start, start); 330 rend = ulmin(s->r_end, ulmax(start + count, end)); 331 if (s->r_start >= start && s->r_end <= end 332 && (s->r_end - s->r_start + 1) == count && 333 (s->r_start & amask) == 0 && 334 ((s->r_start ^ s->r_end) & bmask) == 0) { 335 rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT | M_ZERO); 336 if (rv == 0) 337 goto out; 338 rv->r_start = s->r_start; 339 rv->r_end = s->r_end; 340 rv->r_flags = s->r_flags & 341 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE); 342 rv->r_dev = dev; 343 rv->r_rm = rm; 344 if (s->r_sharehead == 0) { 345 s->r_sharehead = malloc(sizeof *s->r_sharehead, 346 M_RMAN, M_NOWAIT | M_ZERO); 347 if (s->r_sharehead == 0) { 348 free(rv, M_RMAN); 349 rv = 0; 350 goto out; 351 } 352 LIST_INIT(s->r_sharehead); 353 LIST_INSERT_HEAD(s->r_sharehead, s, 354 r_sharelink); 355 s->r_flags |= RF_FIRSTSHARE; 356 } 357 rv->r_sharehead = s->r_sharehead; 358 LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink); 359 goto out; 360 } 361 } 362 363 /* 364 * We couldn't find anything. 365 */ 366 out: 367 /* 368 * If the user specified RF_ACTIVE in the initial flags, 369 * which is reflected in `want_activate', we attempt to atomically 370 * activate the resource. If this fails, we release the resource 371 * and indicate overall failure. (This behavior probably doesn't 372 * make sense for RF_TIMESHARE-type resources.) 373 */ 374 if (rv && want_activate) { 375 struct resource *whohas; 376 if (int_rman_activate_resource(rm, rv, &whohas)) { 377 int_rman_release_resource(rm, rv); 378 rv = 0; 379 } 380 } 381 382 mtx_unlock(rm->rm_mtx); 383 return (rv); 384 } 385 386 struct resource * 387 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count, 388 u_int flags, struct device *dev) 389 { 390 391 return (rman_reserve_resource_bound(rm, start, end, count, 0, flags, 392 dev)); 393 } 394 395 static int 396 int_rman_activate_resource(struct rman *rm, struct resource *r, 397 struct resource **whohas) 398 { 399 struct resource *s; 400 int ok; 401 402 /* 403 * If we are not timesharing, then there is nothing much to do. 404 * If we already have the resource, then there is nothing at all to do. 405 * If we are not on a sharing list with anybody else, then there is 406 * little to do. 407 */ 408 if ((r->r_flags & RF_TIMESHARE) == 0 409 || (r->r_flags & RF_ACTIVE) != 0 410 || r->r_sharehead == 0) { 411 r->r_flags |= RF_ACTIVE; 412 return 0; 413 } 414 415 ok = 1; 416 for (s = LIST_FIRST(r->r_sharehead); s && ok; 417 s = LIST_NEXT(s, r_sharelink)) { 418 if ((s->r_flags & RF_ACTIVE) != 0) { 419 ok = 0; 420 *whohas = s; 421 } 422 } 423 if (ok) { 424 r->r_flags |= RF_ACTIVE; 425 return 0; 426 } 427 return EBUSY; 428 } 429 430 int 431 rman_activate_resource(struct resource *r) 432 { 433 int rv; 434 struct resource *whohas; 435 struct rman *rm; 436 437 rm = r->r_rm; 438 mtx_lock(rm->rm_mtx); 439 rv = int_rman_activate_resource(rm, r, &whohas); 440 mtx_unlock(rm->rm_mtx); 441 return rv; 442 } 443 444 int 445 rman_await_resource(struct resource *r, int pri, int timo) 446 { 447 int rv; 448 struct resource *whohas; 449 struct rman *rm; 450 451 rm = r->r_rm; 452 mtx_lock(rm->rm_mtx); 453 for (;;) { 454 rv = int_rman_activate_resource(rm, r, &whohas); 455 if (rv != EBUSY) 456 return (rv); /* returns with mutex held */ 457 458 if (r->r_sharehead == 0) 459 panic("rman_await_resource"); 460 whohas->r_flags |= RF_WANTED; 461 rv = msleep(r->r_sharehead, rm->rm_mtx, pri, "rmwait", timo); 462 if (rv) { 463 mtx_unlock(rm->rm_mtx); 464 return (rv); 465 } 466 } 467 } 468 469 static int 470 int_rman_deactivate_resource(struct resource *r) 471 { 472 struct rman *rm; 473 474 rm = r->r_rm; 475 r->r_flags &= ~RF_ACTIVE; 476 if (r->r_flags & RF_WANTED) { 477 r->r_flags &= ~RF_WANTED; 478 wakeup(r->r_sharehead); 479 } 480 return 0; 481 } 482 483 int 484 rman_deactivate_resource(struct resource *r) 485 { 486 struct rman *rm; 487 488 rm = r->r_rm; 489 mtx_lock(rm->rm_mtx); 490 int_rman_deactivate_resource(r); 491 mtx_unlock(rm->rm_mtx); 492 return 0; 493 } 494 495 static int 496 int_rman_release_resource(struct rman *rm, struct resource *r) 497 { 498 struct resource *s, *t; 499 500 if (r->r_flags & RF_ACTIVE) 501 int_rman_deactivate_resource(r); 502 503 /* 504 * Check for a sharing list first. If there is one, then we don't 505 * have to think as hard. 506 */ 507 if (r->r_sharehead) { 508 /* 509 * If a sharing list exists, then we know there are at 510 * least two sharers. 511 * 512 * If we are in the main circleq, appoint someone else. 513 */ 514 LIST_REMOVE(r, r_sharelink); 515 s = LIST_FIRST(r->r_sharehead); 516 if (r->r_flags & RF_FIRSTSHARE) { 517 s->r_flags |= RF_FIRSTSHARE; 518 TAILQ_INSERT_BEFORE(r, s, r_link); 519 TAILQ_REMOVE(&rm->rm_list, r, r_link); 520 } 521 522 /* 523 * Make sure that the sharing list goes away completely 524 * if the resource is no longer being shared at all. 525 */ 526 if (LIST_NEXT(s, r_sharelink) == 0) { 527 free(s->r_sharehead, M_RMAN); 528 s->r_sharehead = 0; 529 s->r_flags &= ~RF_FIRSTSHARE; 530 } 531 goto out; 532 } 533 534 /* 535 * Look at the adjacent resources in the list and see if our 536 * segment can be merged with any of them. 537 */ 538 s = TAILQ_PREV(r, resource_head, r_link); 539 t = TAILQ_NEXT(r, r_link); 540 541 if (s != NULL && (s->r_flags & RF_ALLOCATED) == 0 542 && t != NULL && (t->r_flags & RF_ALLOCATED) == 0) { 543 /* 544 * Merge all three segments. 545 */ 546 s->r_end = t->r_end; 547 TAILQ_REMOVE(&rm->rm_list, r, r_link); 548 TAILQ_REMOVE(&rm->rm_list, t, r_link); 549 free(t, M_RMAN); 550 } else if (s != NULL && (s->r_flags & RF_ALLOCATED) == 0) { 551 /* 552 * Merge previous segment with ours. 553 */ 554 s->r_end = r->r_end; 555 TAILQ_REMOVE(&rm->rm_list, r, r_link); 556 } else if (t != NULL && (t->r_flags & RF_ALLOCATED) == 0) { 557 /* 558 * Merge next segment with ours. 559 */ 560 t->r_start = r->r_start; 561 TAILQ_REMOVE(&rm->rm_list, r, r_link); 562 } else { 563 /* 564 * At this point, we know there is nothing we 565 * can potentially merge with, because on each 566 * side, there is either nothing there or what is 567 * there is still allocated. In that case, we don't 568 * want to remove r from the list; we simply want to 569 * change it to an unallocated region and return 570 * without freeing anything. 571 */ 572 r->r_flags &= ~RF_ALLOCATED; 573 return 0; 574 } 575 576 out: 577 free(r, M_RMAN); 578 return 0; 579 } 580 581 int 582 rman_release_resource(struct resource *r) 583 { 584 int rv; 585 struct rman *rm = r->r_rm; 586 587 mtx_lock(rm->rm_mtx); 588 rv = int_rman_release_resource(rm, r); 589 mtx_unlock(rm->rm_mtx); 590 return (rv); 591 } 592 593 uint32_t 594 rman_make_alignment_flags(uint32_t size) 595 { 596 int i; 597 598 /* 599 * Find the hightest bit set, and add one if more than one bit 600 * set. We're effectively computing the ceil(log2(size)) here. 601 */ 602 for (i = 31; i > 0; i--) 603 if ((1 << i) & size) 604 break; 605 if (~(1 << i) & size) 606 i++; 607 608 return(RF_ALIGNMENT_LOG2(i)); 609 } 610