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 1.13 2007/09/21 02:28:00 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 #include <sys/sysctl.h> 69 70 int rman_debug = 0; 71 TUNABLE_INT("debug.rman_debug", &rman_debug); 72 SYSCTL_INT(_debug, OID_AUTO, rman_debug, CTLFLAG_RW, 73 &rman_debug, 0, "rman debug"); 74 75 #define DPRINTF(params) if (rman_debug) kprintf params 76 77 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager"); 78 79 struct rman_head rman_head; 80 static struct lwkt_token rman_tok; /* mutex to protect rman_head */ 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 #define CIRCLEQ_TERMCOND(var, head) (var == (void *)&(head)) 87 88 int 89 rman_init(struct rman *rm) 90 { 91 static int once; 92 lwkt_tokref ilock; 93 94 if (once == 0) { 95 once = 1; 96 TAILQ_INIT(&rman_head); 97 lwkt_token_init(&rman_tok); 98 } 99 100 if (rm->rm_type == RMAN_UNINIT) 101 panic("rman_init"); 102 if (rm->rm_type == RMAN_GAUGE) 103 panic("implement RMAN_GAUGE"); 104 105 CIRCLEQ_INIT(&rm->rm_list); 106 rm->rm_slock = kmalloc(sizeof *rm->rm_slock, M_RMAN, M_NOWAIT); 107 if (rm->rm_slock == NULL) 108 return ENOMEM; 109 lwkt_token_init(rm->rm_slock); 110 111 lwkt_gettoken(&ilock, &rman_tok); 112 TAILQ_INSERT_TAIL(&rman_head, rm, rm_link); 113 lwkt_reltoken(&ilock); 114 return 0; 115 } 116 117 /* 118 * NB: this interface is not robust against programming errors which 119 * add multiple copies of the same region. 120 */ 121 int 122 rman_manage_region(struct rman *rm, u_long start, u_long end) 123 { 124 struct resource *r, *s; 125 lwkt_tokref ilock; 126 127 DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n", 128 rm->rm_descr, start, end)); 129 r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT); 130 if (r == 0) 131 return ENOMEM; 132 bzero(r, sizeof *r); 133 r->r_sharehead = 0; 134 r->r_start = start; 135 r->r_end = end; 136 r->r_flags = 0; 137 r->r_dev = 0; 138 r->r_rm = rm; 139 140 lwkt_gettoken(&ilock, rm->rm_slock); 141 for (s = CIRCLEQ_FIRST(&rm->rm_list); 142 !CIRCLEQ_TERMCOND(s, rm->rm_list) && s->r_end < r->r_start; 143 s = CIRCLEQ_NEXT(s, r_link)) 144 ; 145 146 if (CIRCLEQ_TERMCOND(s, rm->rm_list)) { 147 CIRCLEQ_INSERT_TAIL(&rm->rm_list, r, r_link); 148 } else { 149 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, r, r_link); 150 } 151 152 lwkt_reltoken(&ilock); 153 return 0; 154 } 155 156 int 157 rman_fini(struct rman *rm) 158 { 159 struct resource *r; 160 lwkt_tokref ilock; 161 162 lwkt_gettoken(&ilock, rm->rm_slock); 163 CIRCLEQ_FOREACH(r, &rm->rm_list, r_link) { 164 if (r->r_flags & RF_ALLOCATED) { 165 lwkt_reltoken(&ilock); 166 return EBUSY; 167 } 168 } 169 170 /* 171 * There really should only be one of these if we are in this 172 * state and the code is working properly, but it can't hurt. 173 */ 174 while (!CIRCLEQ_EMPTY(&rm->rm_list)) { 175 r = CIRCLEQ_FIRST(&rm->rm_list); 176 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 177 kfree(r, M_RMAN); 178 } 179 lwkt_reltoken(&ilock); 180 /* XXX what's the point of this if we are going to free the struct? */ 181 lwkt_gettoken(&ilock, &rman_tok); 182 TAILQ_REMOVE(&rman_head, rm, rm_link); 183 lwkt_reltoken(&ilock); 184 kfree(rm->rm_slock, M_RMAN); 185 186 return 0; 187 } 188 189 struct resource * 190 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count, 191 u_int flags, struct device *dev) 192 { 193 u_int want_activate; 194 struct resource *r, *s, *rv; 195 u_long rstart, rend; 196 lwkt_tokref ilock; 197 198 rv = 0; 199 200 DPRINTF(("rman_reserve_resource: <%s> request: [%#lx, %#lx], length " 201 "%#lx, flags %u, device %s\n", rm->rm_descr, start, end, 202 count, flags, 203 dev == NULL ? "<null>" : device_get_nameunit(dev))); 204 want_activate = (flags & RF_ACTIVE); 205 flags &= ~RF_ACTIVE; 206 207 lwkt_gettoken(&ilock, rm->rm_slock); 208 209 for (r = CIRCLEQ_FIRST(&rm->rm_list); 210 !CIRCLEQ_TERMCOND(r, rm->rm_list) && r->r_end < start; 211 r = CIRCLEQ_NEXT(r, r_link)) 212 ; 213 214 if (CIRCLEQ_TERMCOND(r, rm->rm_list)) { 215 DPRINTF(("could not find a region\n")); 216 goto out; 217 } 218 219 /* 220 * First try to find an acceptable totally-unshared region. 221 */ 222 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 223 s = CIRCLEQ_NEXT(s, r_link)) { 224 DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end)); 225 if (s->r_start > end) { 226 DPRINTF(("s->r_start (%#lx) > end (%#lx)\n", 227 s->r_start, end)); 228 break; 229 } 230 if (s->r_flags & RF_ALLOCATED) { 231 DPRINTF(("region is allocated\n")); 232 continue; 233 } 234 rstart = max(s->r_start, start); 235 rstart = (rstart + ((1ul << RF_ALIGNMENT(flags))) - 1) & 236 ~((1ul << RF_ALIGNMENT(flags)) - 1); 237 rend = min(s->r_end, max(start + count, end)); 238 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n", 239 rstart, rend, (rend - rstart + 1), count)); 240 241 if ((rend - rstart + 1) >= count) { 242 DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n", 243 rstart, rend, (rend - rstart + 1))); 244 if ((s->r_end - s->r_start + 1) == count) { 245 DPRINTF(("candidate region is entire chunk\n")); 246 rv = s; 247 rv->r_flags |= RF_ALLOCATED | flags; 248 rv->r_dev = dev; 249 goto out; 250 } 251 252 /* 253 * If s->r_start < rstart and 254 * s->r_end > rstart + count - 1, then 255 * we need to split the region into three pieces 256 * (the middle one will get returned to the user). 257 * Otherwise, we are allocating at either the 258 * beginning or the end of s, so we only need to 259 * split it in two. The first case requires 260 * two new allocations; the second requires but one. 261 */ 262 rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT); 263 if (rv == 0) 264 goto out; 265 bzero(rv, sizeof *rv); 266 rv->r_start = rstart; 267 rv->r_end = rstart + count - 1; 268 rv->r_flags = flags | RF_ALLOCATED; 269 rv->r_dev = dev; 270 rv->r_sharehead = 0; 271 rv->r_rm = rm; 272 273 if (s->r_start < rv->r_start && s->r_end > rv->r_end) { 274 DPRINTF(("splitting region in three parts: " 275 "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n", 276 s->r_start, rv->r_start - 1, 277 rv->r_start, rv->r_end, 278 rv->r_end + 1, s->r_end)); 279 /* 280 * We are allocating in the middle. 281 */ 282 r = kmalloc(sizeof *r, M_RMAN, M_NOWAIT); 283 if (r == 0) { 284 kfree(rv, M_RMAN); 285 rv = 0; 286 goto out; 287 } 288 bzero(r, sizeof *r); 289 r->r_start = rv->r_end + 1; 290 r->r_end = s->r_end; 291 r->r_flags = s->r_flags; 292 r->r_dev = 0; 293 r->r_sharehead = 0; 294 r->r_rm = rm; 295 s->r_end = rv->r_start - 1; 296 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 297 r_link); 298 CIRCLEQ_INSERT_AFTER(&rm->rm_list, rv, r, 299 r_link); 300 } else if (s->r_start == rv->r_start) { 301 DPRINTF(("allocating from the beginning\n")); 302 /* 303 * We are allocating at the beginning. 304 */ 305 s->r_start = rv->r_end + 1; 306 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, s, rv, 307 r_link); 308 } else { 309 DPRINTF(("allocating at the end\n")); 310 /* 311 * We are allocating at the end. 312 */ 313 s->r_end = rv->r_start - 1; 314 CIRCLEQ_INSERT_AFTER(&rm->rm_list, s, rv, 315 r_link); 316 } 317 goto out; 318 } 319 } 320 321 /* 322 * Now find an acceptable shared region, if the client's requirements 323 * allow sharing. By our implementation restriction, a candidate 324 * region must match exactly by both size and sharing type in order 325 * to be considered compatible with the client's request. (The 326 * former restriction could probably be lifted without too much 327 * additional work, but this does not seem warranted.) 328 */ 329 DPRINTF(("no unshared regions found\n")); 330 if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0) 331 goto out; 332 333 for (s = r; !CIRCLEQ_TERMCOND(s, rm->rm_list); 334 s = CIRCLEQ_NEXT(s, r_link)) { 335 if (s->r_start > end) 336 break; 337 if ((s->r_flags & flags) != flags) 338 continue; 339 rstart = max(s->r_start, start); 340 rend = min(s->r_end, max(start + count, end)); 341 if (s->r_start >= start && s->r_end <= end 342 && (s->r_end - s->r_start + 1) == count) { 343 rv = kmalloc(sizeof *rv, M_RMAN, M_NOWAIT); 344 if (rv == 0) 345 goto out; 346 bzero(rv, sizeof *rv); 347 rv->r_start = s->r_start; 348 rv->r_end = s->r_end; 349 rv->r_flags = s->r_flags & 350 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE); 351 rv->r_dev = dev; 352 rv->r_rm = rm; 353 if (s->r_sharehead == 0) { 354 s->r_sharehead = kmalloc(sizeof *s->r_sharehead, 355 M_RMAN, M_NOWAIT); 356 if (s->r_sharehead == 0) { 357 kfree(rv, M_RMAN); 358 rv = 0; 359 goto out; 360 } 361 bzero(s->r_sharehead, sizeof *s->r_sharehead); 362 LIST_INIT(s->r_sharehead); 363 LIST_INSERT_HEAD(s->r_sharehead, s, 364 r_sharelink); 365 s->r_flags |= RF_FIRSTSHARE; 366 } 367 rv->r_sharehead = s->r_sharehead; 368 LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink); 369 goto out; 370 } 371 } 372 373 /* 374 * We couldn't find anything. 375 */ 376 out: 377 /* 378 * If the user specified RF_ACTIVE in the initial flags, 379 * which is reflected in `want_activate', we attempt to atomically 380 * activate the resource. If this fails, we release the resource 381 * and indicate overall failure. (This behavior probably doesn't 382 * make sense for RF_TIMESHARE-type resources.) 383 */ 384 if (rv && want_activate) { 385 struct resource *whohas; 386 if (int_rman_activate_resource(rm, rv, &whohas)) { 387 int_rman_release_resource(rm, rv); 388 rv = 0; 389 } 390 } 391 lwkt_reltoken(&ilock); 392 return (rv); 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 lwkt_tokref ilock; 436 struct rman *rm; 437 438 rm = r->r_rm; 439 lwkt_gettoken(&ilock, rm->rm_slock); 440 rv = int_rman_activate_resource(rm, r, &whohas); 441 lwkt_reltoken(&ilock); 442 return rv; 443 } 444 445 #if 0 446 447 /* XXX */ 448 int 449 rman_await_resource(struct resource *r, lwkt_tokref_t ilock, int slpflags, int timo) 450 { 451 int rv; 452 struct resource *whohas; 453 struct rman *rm; 454 455 rm = r->r_rm; 456 for (;;) { 457 lwkt_gettoken(ilock, rm->rm_slock); 458 rv = int_rman_activate_resource(rm, r, &whohas); 459 if (rv != EBUSY) 460 return (rv); /* returns with ilock held */ 461 462 if (r->r_sharehead == 0) 463 panic("rman_await_resource"); 464 /* 465 * A critical section will hopefully will prevent a race 466 * between lwkt_reltoken and tsleep where a process 467 * could conceivably get in and release the resource 468 * before we have a chance to sleep on it. YYY 469 */ 470 crit_enter(); 471 whohas->r_flags |= RF_WANTED; 472 rv = tsleep(r->r_sharehead, slpflags, "rmwait", timo); 473 if (rv) { 474 lwkt_reltoken(ilock); 475 crit_exit(); 476 return rv; 477 } 478 crit_exit(); 479 } 480 } 481 482 #endif 483 484 static int 485 int_rman_deactivate_resource(struct resource *r) 486 { 487 struct rman *rm; 488 489 rm = r->r_rm; 490 r->r_flags &= ~RF_ACTIVE; 491 if (r->r_flags & RF_WANTED) { 492 r->r_flags &= ~RF_WANTED; 493 wakeup(r->r_sharehead); 494 } 495 return 0; 496 } 497 498 int 499 rman_deactivate_resource(struct resource *r) 500 { 501 lwkt_tokref ilock; 502 struct rman *rm; 503 504 rm = r->r_rm; 505 lwkt_gettoken(&ilock, rm->rm_slock); 506 int_rman_deactivate_resource(r); 507 lwkt_reltoken(&ilock); 508 return 0; 509 } 510 511 static int 512 int_rman_release_resource(struct rman *rm, struct resource *r) 513 { 514 struct resource *s, *t; 515 516 if (r->r_flags & RF_ACTIVE) 517 int_rman_deactivate_resource(r); 518 519 /* 520 * Check for a sharing list first. If there is one, then we don't 521 * have to think as hard. 522 */ 523 if (r->r_sharehead) { 524 /* 525 * If a sharing list exists, then we know there are at 526 * least two sharers. 527 * 528 * If we are in the main circleq, appoint someone else. 529 */ 530 LIST_REMOVE(r, r_sharelink); 531 s = LIST_FIRST(r->r_sharehead); 532 if (r->r_flags & RF_FIRSTSHARE) { 533 s->r_flags |= RF_FIRSTSHARE; 534 CIRCLEQ_INSERT_BEFORE(&rm->rm_list, r, s, r_link); 535 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 536 } 537 538 /* 539 * Make sure that the sharing list goes away completely 540 * if the resource is no longer being shared at all. 541 */ 542 if (LIST_NEXT(s, r_sharelink) == 0) { 543 kfree(s->r_sharehead, M_RMAN); 544 s->r_sharehead = 0; 545 s->r_flags &= ~RF_FIRSTSHARE; 546 } 547 goto out; 548 } 549 550 /* 551 * Look at the adjacent resources in the list and see if our 552 * segment can be merged with any of them. 553 */ 554 s = CIRCLEQ_PREV(r, r_link); 555 t = CIRCLEQ_NEXT(r, r_link); 556 557 if (s != (void *)&rm->rm_list && (s->r_flags & RF_ALLOCATED) == 0 558 && t != (void *)&rm->rm_list && (t->r_flags & RF_ALLOCATED) == 0) { 559 /* 560 * Merge all three segments. 561 */ 562 s->r_end = t->r_end; 563 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 564 CIRCLEQ_REMOVE(&rm->rm_list, t, r_link); 565 kfree(t, M_RMAN); 566 } else if (s != (void *)&rm->rm_list 567 && (s->r_flags & RF_ALLOCATED) == 0) { 568 /* 569 * Merge previous segment with ours. 570 */ 571 s->r_end = r->r_end; 572 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 573 } else if (t != (void *)&rm->rm_list 574 && (t->r_flags & RF_ALLOCATED) == 0) { 575 /* 576 * Merge next segment with ours. 577 */ 578 t->r_start = r->r_start; 579 CIRCLEQ_REMOVE(&rm->rm_list, r, r_link); 580 } else { 581 /* 582 * At this point, we know there is nothing we 583 * can potentially merge with, because on each 584 * side, there is either nothing there or what is 585 * there is still allocated. In that case, we don't 586 * want to remove r from the list; we simply want to 587 * change it to an unallocated region and return 588 * without freeing anything. 589 */ 590 r->r_flags &= ~RF_ALLOCATED; 591 return 0; 592 } 593 594 out: 595 kfree(r, M_RMAN); 596 return 0; 597 } 598 599 int 600 rman_release_resource(struct resource *r) 601 { 602 struct rman *rm = r->r_rm; 603 lwkt_tokref ilock; 604 int rv; 605 606 lwkt_gettoken(&ilock, rm->rm_slock); 607 rv = int_rman_release_resource(rm, r); 608 lwkt_reltoken(&ilock); 609 return (rv); 610 } 611 612 uint32_t 613 rman_make_alignment_flags(uint32_t size) 614 { 615 int i; 616 617 /* 618 * Find the hightest bit set, and add one if more than one bit 619 * set. We're effectively computing the ceil(log2(size)) here. 620 */ 621 for (i = 32; i > 0; i--) 622 if ((1 << i) & size) 623 break; 624 if (~(1 << i) & size) 625 i++; 626 627 return(RF_ALIGNMENT_LOG2(i)); 628 } 629