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/bus.h> /* XXX debugging */ 66 #include <machine/bus.h> 67 #include <sys/rman.h> 68 69 #ifdef RMAN_DEBUG 70 #define DPRINTF(params) printf##params 71 #else 72 #define DPRINTF(params) 73 #endif 74 75 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager"); 76 77 struct rman_head rman_head; 78 #ifndef NULL_SIMPLELOCKS 79 static struct simplelock rman_lock; /* mutex to protect rman_head */ 80 #endif 81 static int int_rman_activate_resource(struct rman *rm, struct resource *r, 82 struct resource **whohas); 83 static int int_rman_deactivate_resource(struct resource *r); 84 static int int_rman_release_resource(struct rman *rm, struct resource *r); 85 86 int 87 rman_init(struct rman *rm) 88 { 89 static int once; 90 91 if (once == 0) { 92 once = 1; 93 TAILQ_INIT(&rman_head); 94 simple_lock_init(&rman_lock); 95 } 96 97 if (rm->rm_type == RMAN_UNINIT) 98 panic("rman_init"); 99 if (rm->rm_type == RMAN_GAUGE) 100 panic("implement RMAN_GAUGE"); 101 102 TAILQ_INIT(&rm->rm_list); 103 rm->rm_slock = malloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT); 104 if (rm->rm_slock == 0) 105 return ENOMEM; 106 simple_lock_init(rm->rm_slock); 107 108 simple_lock(&rman_lock); 109 TAILQ_INSERT_TAIL(&rman_head, rm, rm_link); 110 simple_unlock(&rman_lock); 111 return 0; 112 } 113 114 /* 115 * NB: this interface is not robust against programming errors which 116 * add multiple copies of the same region. 117 */ 118 int 119 rman_manage_region(struct rman *rm, u_long start, u_long end) 120 { 121 struct resource *r, *s; 122 123 r = malloc(sizeof *r, M_RMAN, M_NOWAIT); 124 if (r == 0) 125 return ENOMEM; 126 bzero(r, sizeof *r); 127 r->r_sharehead = 0; 128 r->r_start = start; 129 r->r_end = end; 130 r->r_flags = 0; 131 r->r_dev = 0; 132 r->r_rm = rm; 133 134 simple_lock(rm->rm_slock); 135 for (s = TAILQ_FIRST(&rm->rm_list); 136 s && s->r_end < r->r_start; 137 s = TAILQ_NEXT(s, r_link)) 138 ; 139 140 if (s == NULL) { 141 TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link); 142 } else { 143 TAILQ_INSERT_BEFORE(s, r, r_link); 144 } 145 146 simple_unlock(rm->rm_slock); 147 return 0; 148 } 149 150 int 151 rman_fini(struct rman *rm) 152 { 153 struct resource *r; 154 155 simple_lock(rm->rm_slock); 156 TAILQ_FOREACH(r, &rm->rm_list, r_link) { 157 if (r->r_flags & RF_ALLOCATED) { 158 simple_unlock(rm->rm_slock); 159 return EBUSY; 160 } 161 } 162 163 /* 164 * There really should only be one of these if we are in this 165 * state and the code is working properly, but it can't hurt. 166 */ 167 while (!TAILQ_EMPTY(&rm->rm_list)) { 168 r = TAILQ_FIRST(&rm->rm_list); 169 TAILQ_REMOVE(&rm->rm_list, r, r_link); 170 free(r, M_RMAN); 171 } 172 simple_unlock(rm->rm_slock); 173 simple_lock(&rman_lock); 174 TAILQ_REMOVE(&rman_head, rm, rm_link); 175 simple_unlock(&rman_lock); 176 free(rm->rm_slock, M_RMAN); 177 178 return 0; 179 } 180 181 struct resource * 182 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count, 183 u_int flags, struct device *dev) 184 { 185 u_int want_activate; 186 struct resource *r, *s, *rv; 187 u_long rstart, rend; 188 189 rv = 0; 190 191 DPRINTF(("rman_reserve_resource: <%s> request: [%#lx, %#lx], length " 192 "%#lx, flags %u, device %s%d\n", rm->rm_descr, start, end, 193 count, flags, device_get_name(dev), device_get_unit(dev))); 194 want_activate = (flags & RF_ACTIVE); 195 flags &= ~RF_ACTIVE; 196 197 simple_lock(rm->rm_slock); 198 199 for (r = TAILQ_FIRST(&rm->rm_list); 200 r && r->r_end < start; 201 r = TAILQ_NEXT(r, r_link)) 202 ; 203 204 if (r == NULL) { 205 DPRINTF(("could not find a region\n")); 206 goto out; 207 } 208 209 /* 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 = max(s->r_start, start); 223 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) & 224 ~((1ul << RF_ALIGNMENT(flags)) - 1); 225 rend = min(s->r_end, max(rstart + count, end)); 226 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n", 227 rstart, rend, (rend - rstart + 1), count)); 228 229 if ((rend - rstart + 1) >= count) { 230 DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n", 231 rend, rstart, (rend - rstart + 1))); 232 if ((s->r_end - s->r_start + 1) == count) { 233 DPRINTF(("candidate region is entire chunk\n")); 234 rv = s; 235 rv->r_flags |= RF_ALLOCATED | flags; 236 rv->r_dev = dev; 237 goto out; 238 } 239 240 /* 241 * If s->r_start < rstart and 242 * s->r_end > rstart + count - 1, then 243 * we need to split the region into three pieces 244 * (the middle one will get returned to the user). 245 * Otherwise, we are allocating at either the 246 * beginning or the end of s, so we only need to 247 * split it in two. The first case requires 248 * two new allocations; the second requires but one. 249 */ 250 rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT); 251 if (rv == 0) 252 goto out; 253 bzero(rv, sizeof *rv); 254 rv->r_start = rstart; 255 rv->r_end = rstart + count - 1; 256 rv->r_flags = flags | RF_ALLOCATED; 257 rv->r_dev = dev; 258 rv->r_sharehead = 0; 259 rv->r_rm = rm; 260 261 if (s->r_start < rv->r_start && s->r_end > rv->r_end) { 262 DPRINTF(("splitting region in three parts: " 263 "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n", 264 s->r_start, rv->r_start - 1, 265 rv->r_start, rv->r_end, 266 rv->r_end + 1, s->r_end)); 267 /* 268 * We are allocating in the middle. 269 */ 270 r = malloc(sizeof *r, M_RMAN, M_NOWAIT); 271 if (r == 0) { 272 free(rv, M_RMAN); 273 rv = 0; 274 goto out; 275 } 276 bzero(r, sizeof *r); 277 r->r_start = rv->r_end + 1; 278 r->r_end = s->r_end; 279 r->r_flags = s->r_flags; 280 r->r_dev = 0; 281 r->r_sharehead = 0; 282 r->r_rm = rm; 283 s->r_end = rv->r_start - 1; 284 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv, 285 r_link); 286 TAILQ_INSERT_AFTER(&rm->rm_list, rv, r, 287 r_link); 288 } else if (s->r_start == rv->r_start) { 289 DPRINTF(("allocating from the beginning\n")); 290 /* 291 * We are allocating at the beginning. 292 */ 293 s->r_start = rv->r_end + 1; 294 TAILQ_INSERT_BEFORE(s, rv, r_link); 295 } else { 296 DPRINTF(("allocating at the end\n")); 297 /* 298 * We are allocating at the end. 299 */ 300 s->r_end = rv->r_start - 1; 301 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv, 302 r_link); 303 } 304 goto out; 305 } 306 } 307 308 /* 309 * Now find an acceptable shared region, if the client's requirements 310 * allow sharing. By our implementation restriction, a candidate 311 * region must match exactly by both size and sharing type in order 312 * to be considered compatible with the client's request. (The 313 * former restriction could probably be lifted without too much 314 * additional work, but this does not seem warranted.) 315 */ 316 DPRINTF(("no unshared regions found\n")); 317 if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0) 318 goto out; 319 320 for (s = r; s; s = TAILQ_NEXT(s, r_link)) { 321 if (s->r_start > end) 322 break; 323 if ((s->r_flags & flags) != flags) 324 continue; 325 rstart = max(s->r_start, start); 326 rend = min(s->r_end, max(start + count, end)); 327 if (s->r_start >= start && s->r_end <= end 328 && (s->r_end - s->r_start + 1) == count) { 329 rv = malloc(sizeof *rv, M_RMAN, M_NOWAIT); 330 if (rv == 0) 331 goto out; 332 bzero(rv, sizeof *rv); 333 rv->r_start = s->r_start; 334 rv->r_end = s->r_end; 335 rv->r_flags = s->r_flags & 336 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE); 337 rv->r_dev = dev; 338 rv->r_rm = rm; 339 if (s->r_sharehead == 0) { 340 s->r_sharehead = malloc(sizeof *s->r_sharehead, 341 M_RMAN, M_NOWAIT); 342 if (s->r_sharehead == 0) { 343 free(rv, M_RMAN); 344 rv = 0; 345 goto out; 346 } 347 bzero(s->r_sharehead, sizeof *s->r_sharehead); 348 LIST_INIT(s->r_sharehead); 349 LIST_INSERT_HEAD(s->r_sharehead, s, 350 r_sharelink); 351 s->r_flags |= RF_FIRSTSHARE; 352 } 353 rv->r_sharehead = s->r_sharehead; 354 LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink); 355 goto out; 356 } 357 } 358 359 /* 360 * We couldn't find anything. 361 */ 362 out: 363 /* 364 * If the user specified RF_ACTIVE in the initial flags, 365 * which is reflected in `want_activate', we attempt to atomically 366 * activate the resource. If this fails, we release the resource 367 * and indicate overall failure. (This behavior probably doesn't 368 * make sense for RF_TIMESHARE-type resources.) 369 */ 370 if (rv && want_activate) { 371 struct resource *whohas; 372 if (int_rman_activate_resource(rm, rv, &whohas)) { 373 int_rman_release_resource(rm, rv); 374 rv = 0; 375 } 376 } 377 378 simple_unlock(rm->rm_slock); 379 return (rv); 380 } 381 382 static int 383 int_rman_activate_resource(struct rman *rm, struct resource *r, 384 struct resource **whohas) 385 { 386 struct resource *s; 387 int ok; 388 389 /* 390 * If we are not timesharing, then there is nothing much to do. 391 * If we already have the resource, then there is nothing at all to do. 392 * If we are not on a sharing list with anybody else, then there is 393 * little to do. 394 */ 395 if ((r->r_flags & RF_TIMESHARE) == 0 396 || (r->r_flags & RF_ACTIVE) != 0 397 || r->r_sharehead == 0) { 398 r->r_flags |= RF_ACTIVE; 399 return 0; 400 } 401 402 ok = 1; 403 for (s = LIST_FIRST(r->r_sharehead); s && ok; 404 s = LIST_NEXT(s, r_sharelink)) { 405 if ((s->r_flags & RF_ACTIVE) != 0) { 406 ok = 0; 407 *whohas = s; 408 } 409 } 410 if (ok) { 411 r->r_flags |= RF_ACTIVE; 412 return 0; 413 } 414 return EBUSY; 415 } 416 417 int 418 rman_activate_resource(struct resource *r) 419 { 420 int rv; 421 struct resource *whohas; 422 struct rman *rm; 423 424 rm = r->r_rm; 425 simple_lock(rm->rm_slock); 426 rv = int_rman_activate_resource(rm, r, &whohas); 427 simple_unlock(rm->rm_slock); 428 return rv; 429 } 430 431 int 432 rman_await_resource(struct resource *r, int pri, int timo) 433 { 434 int rv, s; 435 struct resource *whohas; 436 struct rman *rm; 437 438 rm = r->r_rm; 439 for (;;) { 440 simple_lock(rm->rm_slock); 441 rv = int_rman_activate_resource(rm, r, &whohas); 442 if (rv != EBUSY) 443 return (rv); /* returns with simplelock */ 444 445 if (r->r_sharehead == 0) 446 panic("rman_await_resource"); 447 /* 448 * splhigh hopefully will prevent a race between 449 * simple_unlock and tsleep where a process 450 * could conceivably get in and release the resource 451 * before we have a chance to sleep on it. 452 */ 453 s = splhigh(); 454 whohas->r_flags |= RF_WANTED; 455 simple_unlock(rm->rm_slock); 456 rv = tsleep(r->r_sharehead, pri, "rmwait", timo); 457 if (rv) { 458 splx(s); 459 return rv; 460 } 461 simple_lock(rm->rm_slock); 462 splx(s); 463 } 464 } 465 466 static int 467 int_rman_deactivate_resource(struct resource *r) 468 { 469 struct rman *rm; 470 471 rm = r->r_rm; 472 r->r_flags &= ~RF_ACTIVE; 473 if (r->r_flags & RF_WANTED) { 474 r->r_flags &= ~RF_WANTED; 475 wakeup(r->r_sharehead); 476 } 477 return 0; 478 } 479 480 int 481 rman_deactivate_resource(struct resource *r) 482 { 483 struct rman *rm; 484 485 rm = r->r_rm; 486 simple_lock(rm->rm_slock); 487 int_rman_deactivate_resource(r); 488 simple_unlock(rm->rm_slock); 489 return 0; 490 } 491 492 static int 493 int_rman_release_resource(struct rman *rm, struct resource *r) 494 { 495 struct resource *s, *t; 496 497 if (r->r_flags & RF_ACTIVE) 498 int_rman_deactivate_resource(r); 499 500 /* 501 * Check for a sharing list first. If there is one, then we don't 502 * have to think as hard. 503 */ 504 if (r->r_sharehead) { 505 /* 506 * If a sharing list exists, then we know there are at 507 * least two sharers. 508 * 509 * If we are in the main circleq, appoint someone else. 510 */ 511 LIST_REMOVE(r, r_sharelink); 512 s = LIST_FIRST(r->r_sharehead); 513 if (r->r_flags & RF_FIRSTSHARE) { 514 s->r_flags |= RF_FIRSTSHARE; 515 TAILQ_INSERT_BEFORE(r, s, r_link); 516 TAILQ_REMOVE(&rm->rm_list, r, r_link); 517 } 518 519 /* 520 * Make sure that the sharing list goes away completely 521 * if the resource is no longer being shared at all. 522 */ 523 if (LIST_NEXT(s, r_sharelink) == 0) { 524 free(s->r_sharehead, M_RMAN); 525 s->r_sharehead = 0; 526 s->r_flags &= ~RF_FIRSTSHARE; 527 } 528 goto out; 529 } 530 531 /* 532 * Look at the adjacent resources in the list and see if our 533 * segment can be merged with any of them. 534 */ 535 s = TAILQ_PREV(r, resource_head, r_link); 536 t = TAILQ_NEXT(r, r_link); 537 538 if (s != NULL && (s->r_flags & RF_ALLOCATED) == 0 539 && t != NULL && (t->r_flags & RF_ALLOCATED) == 0) { 540 /* 541 * Merge all three segments. 542 */ 543 s->r_end = t->r_end; 544 TAILQ_REMOVE(&rm->rm_list, r, r_link); 545 TAILQ_REMOVE(&rm->rm_list, t, r_link); 546 free(t, M_RMAN); 547 } else if (s != NULL && (s->r_flags & RF_ALLOCATED) == 0) { 548 /* 549 * Merge previous segment with ours. 550 */ 551 s->r_end = r->r_end; 552 TAILQ_REMOVE(&rm->rm_list, r, r_link); 553 } else if (t != NULL && (t->r_flags & RF_ALLOCATED) == 0) { 554 /* 555 * Merge next segment with ours. 556 */ 557 t->r_start = r->r_start; 558 TAILQ_REMOVE(&rm->rm_list, r, r_link); 559 } else { 560 /* 561 * At this point, we know there is nothing we 562 * can potentially merge with, because on each 563 * side, there is either nothing there or what is 564 * there is still allocated. In that case, we don't 565 * want to remove r from the list; we simply want to 566 * change it to an unallocated region and return 567 * without freeing anything. 568 */ 569 r->r_flags &= ~RF_ALLOCATED; 570 return 0; 571 } 572 573 out: 574 free(r, M_RMAN); 575 return 0; 576 } 577 578 int 579 rman_release_resource(struct resource *r) 580 { 581 int rv; 582 struct rman *rm = r->r_rm; 583 584 simple_lock(rm->rm_slock); 585 rv = int_rman_release_resource(rm, r); 586 simple_unlock(rm->rm_slock); 587 return (rv); 588 } 589 590 uint32_t 591 rman_make_alignment_flags(uint32_t size) 592 { 593 int i; 594 595 /* 596 * Find the hightest bit set, and add one if more than one bit 597 * set. We're effectively computing the ceil(log2(size)) here. 598 */ 599 for (i = 32; i > 0; i--) 600 if ((1 << i) & size) 601 break; 602 if (~(1 << i) & size) 603 i++; 604 605 return(RF_ALIGNMENT_LOG2(i)); 606 } 607