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: src/sys/kern/subr_rman.c,v 1.10.2.1 2001/06/05 08:06:08 imp Exp $ 30 * $DragonFly: src/sys/kern/subr_rman.c,v 1.12 2007/05/20 07:43:24 y0netan1 Exp $ 31 */ 32 33 /* 34 * The kernel resource manager. This code is responsible for keeping track 35 * of hardware resources which are apportioned out to various drivers. 36 * It does not actually assign those resources, and it is not expected 37 * that end-device drivers will call into this code directly. Rather, 38 * the code which implements the buses that those devices are attached to, 39 * and the code which manages CPU resources, will call this code, and the 40 * end-device drivers will make upcalls to that code to actually perform 41 * the allocation. 42 * 43 * There are two sorts of resources managed by this code. The first is 44 * the more familiar array (RMAN_ARRAY) type; resources in this class 45 * consist of a sequence of individually-allocatable objects which have 46 * been numbered in some well-defined order. Most of the resources 47 * are of this type, as it is the most familiar. The second type is 48 * called a gauge (RMAN_GAUGE), and models fungible resources (i.e., 49 * resources in which each instance is indistinguishable from every 50 * other instance). The principal anticipated application of gauges 51 * is in the context of power consumption, where a bus may have a specific 52 * power budget which all attached devices share. RMAN_GAUGE is not 53 * implemented yet. 54 * 55 * For array resources, we make one simplifying assumption: two clients 56 * sharing the same resource must use the same range of indices. That 57 * is to say, sharing of overlapping-but-not-identical regions is not 58 * permitted. 59 */ 60 61 #include <sys/param.h> 62 #include <sys/systm.h> 63 #include <sys/kernel.h> 64 #include <sys/lock.h> 65 #include <sys/malloc.h> 66 #include <sys/bus.h> /* XXX debugging */ 67 #include <sys/rman.h> 68 69 #ifdef RMAN_DEBUG 70 #define DPRINTF(params) kprintf 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 static struct lwkt_token rman_tok; /* mutex to protect rman_head */ 79 static int int_rman_activate_resource(struct rman *rm, struct resource *r, 80 struct resource **whohas); 81 static int int_rman_deactivate_resource(struct resource *r); 82 static int int_rman_release_resource(struct rman *rm, struct resource *r); 83 84 #define CIRCLEQ_TERMCOND(var, head) (var == (void *)&(head)) 85 86 int 87 rman_init(struct rman *rm) 88 { 89 static int once; 90 lwkt_tokref ilock; 91 92 if (once == 0) { 93 once = 1; 94 TAILQ_INIT(&rman_head); 95 lwkt_token_init(&rman_tok); 96 } 97 98 if (rm->rm_type == RMAN_UNINIT) 99 panic("rman_init"); 100 if (rm->rm_type == RMAN_GAUGE) 101 panic("implement RMAN_GAUGE"); 102 103 CIRCLEQ_INIT(&rm->rm_list); 104 rm->rm_slock = kmalloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT); 105 if (rm->rm_slock == NULL) 106 return ENOMEM; 107 lwkt_token_init(rm->rm_slock); 108 109 lwkt_gettoken(&ilock, &rman_tok); 110 TAILQ_INSERT_TAIL(&rman_head, rm, rm_link); 111 lwkt_reltoken(&ilock); 112 return 0; 113 } 114 115 /* 116 * NB: this interface is not robust against programming errors which 117 * add multiple copies of the same region. 118 */ 119 int 120 rman_manage_region(struct rman *rm, u_long start, u_long end) 121 { 122 struct resource *r, *s; 123 lwkt_tokref ilock; 124 125 DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n", 126 rm->rm_descr, start, end)); 127 r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT); 128 if (r == 0) 129 return ENOMEM; 130 bzero(r, sizeof *r); 131 r->r_sharehead = 0; 132 r->r_start = start; 133 r->r_end = end; 134 r->r_flags = 0; 135 r->r_dev = 0; 136 r->r_rm = rm; 137 138 lwkt_gettoken(&ilock, rm->rm_slock); 139 for (s = CIRCLEQ_FIRST(&rm->rm_list); 140 !CIRCLEQ_TERMCOND(s, rm->rm_list) && s->r_end < r->r_start; 141 s = CIRCLEQ_NEXT(s, r_link)) 142 ; 143 144 if (CIRCLEQ_TERMCOND(s, rm->rm_list)) { 145 CIRCLEQ_INSERT_TAIL(&rm->rm_list, r, r_link); 146 } else { 147 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, r, r_link); 148 } 149 150 lwkt_reltoken(&ilock); 151 return 0; 152 } 153 154 int 155 rman_fini(struct rman *rm) 156 { 157 struct resource *r; 158 lwkt_tokref ilock; 159 160 lwkt_gettoken(&ilock, rm->rm_slock); 161 CIRCLEQ_FOREACH(r, &rm->rm_list, r_link) { 162 if (r->r_flags & RF_ALLOCATED) { 163 lwkt_reltoken(&ilock); 164 return EBUSY; 165 } 166 } 167 168 /* 169 * There really should only be one of these if we are in this 170 * state and the code is working properly, but it can't hurt. 171 */ 172 while (!CIRCLEQ_EMPTY(&rm->rm_list)) { 173 r = CIRCLEQ_FIRST(&rm->rm_list); 174 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 175 kfree(r, M_RMAN); 176 } 177 lwkt_reltoken(&ilock); 178 /* XXX what's the point of this if we are going to free the struct? */ 179 lwkt_gettoken(&ilock, &rman_tok); 180 TAILQ_REMOVE(&rman_head, rm, rm_link); 181 lwkt_reltoken(&ilock); 182 kfree(rm->rm_slock, M_RMAN); 183 184 return 0; 185 } 186 187 struct resource * 188 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count, 189 u_int flags, struct device *dev) 190 { 191 u_int want_activate; 192 struct resource *r, *s, *rv; 193 u_long rstart, rend; 194 lwkt_tokref ilock; 195 196 rv = 0; 197 198 DPRINTF(("rman_reserve_resource: <%s> request: [%#lx, %#lx], length " 199 "%#lx, flags %u, device %s\n", rm->rm_descr, start, end, 200 count, flags, 201 dev == NULL ? "<null>" : device_get_nameunit(dev))); 202 want_activate = (flags & RF_ACTIVE); 203 flags &= ~RF_ACTIVE; 204 205 lwkt_gettoken(&ilock, rm->rm_slock); 206 207 for (r = CIRCLEQ_FIRST(&rm->rm_list); 208 !CIRCLEQ_TERMCOND(r, rm->rm_list) && r->r_end < start; 209 r = CIRCLEQ_NEXT(r, r_link)) 210 ; 211 212 if (CIRCLEQ_TERMCOND(r, rm->rm_list)) { 213 DPRINTF(("could not find a region\n")); 214 goto out; 215 } 216 217 /* 218 * First try to find an acceptable totally-unshared region. 219 */ 220 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 221 s = CIRCLEQ_NEXT(s, r_link)) { 222 DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end)); 223 if (s->r_start > end) { 224 DPRINTF(("s->r_start (%#lx) > end (%#lx)\n", 225 s->r_start, end)); 226 break; 227 } 228 if (s->r_flags & RF_ALLOCATED) { 229 DPRINTF(("region is allocated\n")); 230 continue; 231 } 232 rstart = max(s->r_start, start); 233 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) & 234 ~((1ul << RF_ALIGNMENT(flags)) - 1); 235 rend = min(s->r_end, max(start + count, end)); 236 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n", 237 rstart, rend, (rend - rstart + 1), count)); 238 239 if ((rend - rstart + 1) >= count) { 240 DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n", 241 rstart, rend, (rend - rstart + 1))); 242 if ((s->r_end - s->r_start + 1) == count) { 243 DPRINTF(("candidate region is entire chunk\n")); 244 rv = s; 245 rv->r_flags |= RF_ALLOCATED | flags; 246 rv->r_dev = dev; 247 goto out; 248 } 249 250 /* 251 * If s->r_start < rstart and 252 * s->r_end > rstart + count - 1, then 253 * we need to split the region into three pieces 254 * (the middle one will get returned to the user). 255 * Otherwise, we are allocating at either the 256 * beginning or the end of s, so we only need to 257 * split it in two. The first case requires 258 * two new allocations; the second requires but one. 259 */ 260 rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT); 261 if (rv == 0) 262 goto out; 263 bzero(rv, sizeof *rv); 264 rv->r_start = rstart; 265 rv->r_end = rstart + count - 1; 266 rv->r_flags = flags | RF_ALLOCATED; 267 rv->r_dev = dev; 268 rv->r_sharehead = 0; 269 rv->r_rm = rm; 270 271 if (s->r_start < rv->r_start && s->r_end > rv->r_end) { 272 DPRINTF(("splitting region in three parts: " 273 "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n", 274 s->r_start, rv->r_start - 1, 275 rv->r_start, rv->r_end, 276 rv->r_end + 1, s->r_end)); 277 /* 278 * We are allocating in the middle. 279 */ 280 r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT); 281 if (r == 0) { 282 kfree(rv, M_RMAN); 283 rv = 0; 284 goto out; 285 } 286 bzero(r, sizeof *r); 287 r->r_start = rv->r_end + 1; 288 r->r_end = s->r_end; 289 r->r_flags = s->r_flags; 290 r->r_dev = 0; 291 r->r_sharehead = 0; 292 r->r_rm = rm; 293 s->r_end = rv->r_start - 1; 294 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 295 r_link); 296 CIRCLEQ_INSERT_AFTER(&rm->rm_list, rv, r, 297 r_link); 298 } else if (s->r_start == rv->r_start) { 299 DPRINTF(("allocating from the beginning\n")); 300 /* 301 * We are allocating at the beginning. 302 */ 303 s->r_start = rv->r_end + 1; 304 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, rv, 305 r_link); 306 } else { 307 DPRINTF(("allocating at the end\n")); 308 /* 309 * We are allocating at the end. 310 */ 311 s->r_end = rv->r_start - 1; 312 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 313 r_link); 314 } 315 goto out; 316 } 317 } 318 319 /* 320 * Now find an acceptable shared region, if the client's requirements 321 * allow sharing. By our implementation restriction, a candidate 322 * region must match exactly by both size and sharing type in order 323 * to be considered compatible with the client's request. (The 324 * former restriction could probably be lifted without too much 325 * additional work, but this does not seem warranted.) 326 */ 327 DPRINTF(("no unshared regions found\n")); 328 if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0) 329 goto out; 330 331 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 332 s = CIRCLEQ_NEXT(s, r_link)) { 333 if (s->r_start > end) 334 break; 335 if ((s->r_flags & flags) != flags) 336 continue; 337 rstart = max(s->r_start, start); 338 rend = min(s->r_end, max(start + count, end)); 339 if (s->r_start >= start && s->r_end <= end 340 && (s->r_end - s->r_start + 1) == count) { 341 rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT); 342 if (rv == 0) 343 goto out; 344 bzero(rv, sizeof *rv); 345 rv->r_start = s->r_start; 346 rv->r_end = s->r_end; 347 rv->r_flags = s->r_flags & 348 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE); 349 rv->r_dev = dev; 350 rv->r_rm = rm; 351 if (s->r_sharehead == 0) { 352 s->r_sharehead = kmalloc(sizeof *s->r_sharehead, 353 M_RMAN, M_NOWAIT); 354 if (s->r_sharehead == 0) { 355 kfree(rv, M_RMAN); 356 rv = 0; 357 goto out; 358 } 359 bzero(s->r_sharehead, sizeof *s->r_sharehead); 360 LIST_INIT(s->r_sharehead); 361 LIST_INSERT_HEAD(s->r_sharehead, s, 362 r_sharelink); 363 s->r_flags |= RF_FIRSTSHARE; 364 } 365 rv->r_sharehead = s->r_sharehead; 366 LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink); 367 goto out; 368 } 369 } 370 371 /* 372 * We couldn't find anything. 373 */ 374 out: 375 /* 376 * If the user specified RF_ACTIVE in the initial flags, 377 * which is reflected in `want_activate', we attempt to atomically 378 * activate the resource. If this fails, we release the resource 379 * and indicate overall failure. (This behavior probably doesn't 380 * make sense for RF_TIMESHARE-type resources.) 381 */ 382 if (rv && want_activate) { 383 struct resource *whohas; 384 if (int_rman_activate_resource(rm, rv, &whohas)) { 385 int_rman_release_resource(rm, rv); 386 rv = 0; 387 } 388 } 389 lwkt_reltoken(&ilock); 390 return (rv); 391 } 392 393 static int 394 int_rman_activate_resource(struct rman *rm, struct resource *r, 395 struct resource **whohas) 396 { 397 struct resource *s; 398 int ok; 399 400 /* 401 * If we are not timesharing, then there is nothing much to do. 402 * If we already have the resource, then there is nothing at all to do. 403 * If we are not on a sharing list with anybody else, then there is 404 * little to do. 405 */ 406 if ((r->r_flags & RF_TIMESHARE) == 0 407 || (r->r_flags & RF_ACTIVE) != 0 408 || r->r_sharehead == 0) { 409 r->r_flags |= RF_ACTIVE; 410 return 0; 411 } 412 413 ok = 1; 414 for (s = LIST_FIRST(r->r_sharehead); s && ok; 415 s = LIST_NEXT(s, r_sharelink)) { 416 if ((s->r_flags & RF_ACTIVE) != 0) { 417 ok = 0; 418 *whohas = s; 419 } 420 } 421 if (ok) { 422 r->r_flags |= RF_ACTIVE; 423 return 0; 424 } 425 return EBUSY; 426 } 427 428 int 429 rman_activate_resource(struct resource *r) 430 { 431 int rv; 432 struct resource *whohas; 433 lwkt_tokref ilock; 434 struct rman *rm; 435 436 rm = r->r_rm; 437 lwkt_gettoken(&ilock, rm->rm_slock); 438 rv = int_rman_activate_resource(rm, r, &whohas); 439 lwkt_reltoken(&ilock); 440 return rv; 441 } 442 443 #if 0 444 445 /* XXX */ 446 int 447 rman_await_resource(struct resource *r, lwkt_tokref_t ilock, int slpflags, int timo) 448 { 449 int rv; 450 struct resource *whohas; 451 struct rman *rm; 452 453 rm = r->r_rm; 454 for (;;) { 455 lwkt_gettoken(ilock, rm->rm_slock); 456 rv = int_rman_activate_resource(rm, r, &whohas); 457 if (rv != EBUSY) 458 return (rv); /* returns with ilock held */ 459 460 if (r->r_sharehead == 0) 461 panic("rman_await_resource"); 462 /* 463 * A critical section will hopefully will prevent a race 464 * between lwkt_reltoken and tsleep where a process 465 * could conceivably get in and release the resource 466 * before we have a chance to sleep on it. YYY 467 */ 468 crit_enter(); 469 whohas->r_flags |= RF_WANTED; 470 rv = tsleep(r->r_sharehead, slpflags, "rmwait", timo); 471 if (rv) { 472 lwkt_reltoken(ilock); 473 crit_exit(); 474 return rv; 475 } 476 crit_exit(); 477 } 478 } 479 480 #endif 481 482 static int 483 int_rman_deactivate_resource(struct resource *r) 484 { 485 struct rman *rm; 486 487 rm = r->r_rm; 488 r->r_flags &= ~RF_ACTIVE; 489 if (r->r_flags & RF_WANTED) { 490 r->r_flags &= ~RF_WANTED; 491 wakeup(r->r_sharehead); 492 } 493 return 0; 494 } 495 496 int 497 rman_deactivate_resource(struct resource *r) 498 { 499 lwkt_tokref ilock; 500 struct rman *rm; 501 502 rm = r->r_rm; 503 lwkt_gettoken(&ilock, rm->rm_slock); 504 int_rman_deactivate_resource(r); 505 lwkt_reltoken(&ilock); 506 return 0; 507 } 508 509 static int 510 int_rman_release_resource(struct rman *rm, struct resource *r) 511 { 512 struct resource *s, *t; 513 514 if (r->r_flags & RF_ACTIVE) 515 int_rman_deactivate_resource(r); 516 517 /* 518 * Check for a sharing list first. If there is one, then we don't 519 * have to think as hard. 520 */ 521 if (r->r_sharehead) { 522 /* 523 * If a sharing list exists, then we know there are at 524 * least two sharers. 525 * 526 * If we are in the main circleq, appoint someone else. 527 */ 528 LIST_REMOVE(r, r_sharelink); 529 s = LIST_FIRST(r->r_sharehead); 530 if (r->r_flags & RF_FIRSTSHARE) { 531 s->r_flags |= RF_FIRSTSHARE; 532 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, r, s, r_link); 533 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 534 } 535 536 /* 537 * Make sure that the sharing list goes away completely 538 * if the resource is no longer being shared at all. 539 */ 540 if (LIST_NEXT(s, r_sharelink) == 0) { 541 kfree(s->r_sharehead, M_RMAN); 542 s->r_sharehead = 0; 543 s->r_flags &= ~RF_FIRSTSHARE; 544 } 545 goto out; 546 } 547 548 /* 549 * Look at the adjacent resources in the list and see if our 550 * segment can be merged with any of them. 551 */ 552 s = CIRCLEQ_PREV(r, r_link); 553 t = CIRCLEQ_NEXT(r, r_link); 554 555 if (s != (void *)&rm->rm_list && (s->r_flags & RF_ALLOCATED) == 0 556 && t != (void *)&rm->rm_list && (t->r_flags & RF_ALLOCATED) == 0) { 557 /* 558 * Merge all three segments. 559 */ 560 s->r_end = t->r_end; 561 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 562 CIRCLEQ_REMOVE(&rm->rm_list, t, r_link); 563 kfree(t, M_RMAN); 564 } else if (s != (void *)&rm->rm_list 565 && (s->r_flags & RF_ALLOCATED) == 0) { 566 /* 567 * Merge previous segment with ours. 568 */ 569 s->r_end = r->r_end; 570 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 571 } else if (t != (void *)&rm->rm_list 572 && (t->r_flags & RF_ALLOCATED) == 0) { 573 /* 574 * Merge next segment with ours. 575 */ 576 t->r_start = r->r_start; 577 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 578 } else { 579 /* 580 * At this point, we know there is nothing we 581 * can potentially merge with, because on each 582 * side, there is either nothing there or what is 583 * there is still allocated. In that case, we don't 584 * want to remove r from the list; we simply want to 585 * change it to an unallocated region and return 586 * without freeing anything. 587 */ 588 r->r_flags &= ~RF_ALLOCATED; 589 return 0; 590 } 591 592 out: 593 kfree(r, M_RMAN); 594 return 0; 595 } 596 597 int 598 rman_release_resource(struct resource *r) 599 { 600 struct rman *rm = r->r_rm; 601 lwkt_tokref ilock; 602 int rv; 603 604 lwkt_gettoken(&ilock, rm->rm_slock); 605 rv = int_rman_release_resource(rm, r); 606 lwkt_reltoken(&ilock); 607 return (rv); 608 } 609 610 uint32_t 611 rman_make_alignment_flags(uint32_t size) 612 { 613 int i; 614 615 /* 616 * Find the hightest bit set, and add one if more than one bit 617 * set. We're effectively computing the ceil(log2(size)) here. 618 */ 619 for (i = 32; i > 0; i--) 620 if ((1 << i) & size) 621 break; 622 if (~(1 << i) & size) 623 i++; 624 625 return(RF_ALIGNMENT_LOG2(i)); 626 } 627