xref: /freebsd/sys/kern/subr_rman.c (revision 5ae59dec60e3815b621ae87f74a377cf3449ca55)
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 
30 /*
31  * The kernel resource manager.  This code is responsible for keeping track
32  * of hardware resources which are apportioned out to various drivers.
33  * It does not actually assign those resources, and it is not expected
34  * that end-device drivers will call into this code directly.  Rather,
35  * the code which implements the buses that those devices are attached to,
36  * and the code which manages CPU resources, will call this code, and the
37  * end-device drivers will make upcalls to that code to actually perform
38  * the allocation.
39  *
40  * There are two sorts of resources managed by this code.  The first is
41  * the more familiar array (RMAN_ARRAY) type; resources in this class
42  * consist of a sequence of individually-allocatable objects which have
43  * been numbered in some well-defined order.  Most of the resources
44  * are of this type, as it is the most familiar.  The second type is
45  * called a gauge (RMAN_GAUGE), and models fungible resources (i.e.,
46  * resources in which each instance is indistinguishable from every
47  * other instance).  The principal anticipated application of gauges
48  * is in the context of power consumption, where a bus may have a specific
49  * power budget which all attached devices share.  RMAN_GAUGE is not
50  * implemented yet.
51  *
52  * For array resources, we make one simplifying assumption: two clients
53  * sharing the same resource must use the same range of indices.  That
54  * is to say, sharing of overlapping-but-not-identical regions is not
55  * permitted.
56  */
57 
58 #include "opt_ddb.h"
59 
60 #include <sys/cdefs.h>
61 __FBSDID("$FreeBSD$");
62 
63 #include <sys/param.h>
64 #include <sys/systm.h>
65 #include <sys/kernel.h>
66 #include <sys/limits.h>
67 #include <sys/lock.h>
68 #include <sys/malloc.h>
69 #include <sys/mutex.h>
70 #include <sys/bus.h>		/* XXX debugging */
71 #include <machine/bus.h>
72 #include <sys/rman.h>
73 #include <sys/sysctl.h>
74 
75 #ifdef DDB
76 #include <ddb/ddb.h>
77 #endif
78 
79 /*
80  * We use a linked list rather than a bitmap because we need to be able to
81  * represent potentially huge objects (like all of a processor's physical
82  * address space).  That is also why the indices are defined to have type
83  * `unsigned long' -- that being the largest integral type in ISO C (1990).
84  * The 1999 version of C allows `long long'; we may need to switch to that
85  * at some point in the future, particularly if we want to support 36-bit
86  * addresses on IA32 hardware.
87  */
88 struct resource_i {
89 	struct resource		r_r;
90 	TAILQ_ENTRY(resource_i)	r_link;
91 	LIST_ENTRY(resource_i)	r_sharelink;
92 	LIST_HEAD(, resource_i)	*r_sharehead;
93 	u_long	r_start;	/* index of the first entry in this resource */
94 	u_long	r_end;		/* index of the last entry (inclusive) */
95 	u_int	r_flags;
96 	void	*r_virtual;	/* virtual address of this resource */
97 	struct	device *r_dev;	/* device which has allocated this resource */
98 	struct	rman *r_rm;	/* resource manager from whence this came */
99 	int	r_rid;		/* optional rid for this resource. */
100 };
101 
102 static int     rman_debug = 0;
103 TUNABLE_INT("debug.rman_debug", &rman_debug);
104 SYSCTL_INT(_debug, OID_AUTO, rman_debug, CTLFLAG_RW,
105     &rman_debug, 0, "rman debug");
106 
107 #define DPRINTF(params) if (rman_debug) printf params
108 
109 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
110 
111 struct	rman_head rman_head;
112 static	struct mtx rman_mtx; /* mutex to protect rman_head */
113 static	int int_rman_activate_resource(struct rman *rm, struct resource_i *r,
114 				       struct resource_i **whohas);
115 static	int int_rman_deactivate_resource(struct resource_i *r);
116 static	int int_rman_release_resource(struct rman *rm, struct resource_i *r);
117 
118 static __inline struct resource_i *
119 int_alloc_resource(int malloc_flag)
120 {
121 	struct resource_i *r;
122 
123 	r = malloc(sizeof *r, M_RMAN, malloc_flag | M_ZERO);
124 	if (r != NULL) {
125 		r->r_r.__r_i = r;
126 	}
127 	return (r);
128 }
129 
130 int
131 rman_init(struct rman *rm)
132 {
133 	static int once = 0;
134 
135 	if (once == 0) {
136 		once = 1;
137 		TAILQ_INIT(&rman_head);
138 		mtx_init(&rman_mtx, "rman head", NULL, MTX_DEF);
139 	}
140 
141 	if (rm->rm_start == 0 && rm->rm_end == 0)
142 		rm->rm_end = ~0ul;
143 	if (rm->rm_type == RMAN_UNINIT)
144 		panic("rman_init");
145 	if (rm->rm_type == RMAN_GAUGE)
146 		panic("implement RMAN_GAUGE");
147 
148 	TAILQ_INIT(&rm->rm_list);
149 	rm->rm_mtx = malloc(sizeof *rm->rm_mtx, M_RMAN, M_NOWAIT | M_ZERO);
150 	if (rm->rm_mtx == NULL)
151 		return ENOMEM;
152 	mtx_init(rm->rm_mtx, "rman", NULL, MTX_DEF);
153 
154 	mtx_lock(&rman_mtx);
155 	TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
156 	mtx_unlock(&rman_mtx);
157 	return 0;
158 }
159 
160 int
161 rman_manage_region(struct rman *rm, u_long start, u_long end)
162 {
163 	struct resource_i *r, *s, *t;
164 	int rv = 0;
165 
166 	DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
167 	    rm->rm_descr, start, end));
168 	if (start < rm->rm_start || end > rm->rm_end)
169 		return EINVAL;
170 	r = int_alloc_resource(M_NOWAIT);
171 	if (r == NULL)
172 		return ENOMEM;
173 	r->r_start = start;
174 	r->r_end = end;
175 	r->r_rm = rm;
176 
177 	mtx_lock(rm->rm_mtx);
178 
179 	/* Skip entries before us. */
180 	TAILQ_FOREACH(s, &rm->rm_list, r_link) {
181 		if (s->r_end == ULONG_MAX)
182 			break;
183 		if (s->r_end + 1 >= r->r_start)
184 			break;
185 	}
186 
187 	/* If we ran off the end of the list, insert at the tail. */
188 	if (s == NULL) {
189 		TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link);
190 	} else {
191 		/* Check for any overlap with the current region. */
192 		if (r->r_start <= s->r_end && r->r_end >= s->r_start) {
193 			rv = EBUSY;
194 			goto out;
195 		}
196 
197 		/* Check for any overlap with the next region. */
198 		t = TAILQ_NEXT(s, r_link);
199 		if (t && r->r_start <= t->r_end && r->r_end >= t->r_start) {
200 			rv = EBUSY;
201 			goto out;
202 		}
203 
204 		/*
205 		 * See if this region can be merged with the next region.  If
206 		 * not, clear the pointer.
207 		 */
208 		if (t && (r->r_end + 1 != t->r_start || t->r_flags != 0))
209 			t = NULL;
210 
211 		/* See if we can merge with the current region. */
212 		if (s->r_end + 1 == r->r_start && s->r_flags == 0) {
213 			/* Can we merge all 3 regions? */
214 			if (t != NULL) {
215 				s->r_end = t->r_end;
216 				TAILQ_REMOVE(&rm->rm_list, t, r_link);
217 				free(r, M_RMAN);
218 				free(t, M_RMAN);
219 			} else {
220 				s->r_end = r->r_end;
221 				free(r, M_RMAN);
222 			}
223 		} else if (t != NULL) {
224 			/* Can we merge with just the next region? */
225 			t->r_start = r->r_start;
226 			free(r, M_RMAN);
227 		} else if (s->r_end < r->r_start) {
228 			TAILQ_INSERT_AFTER(&rm->rm_list, s, r, r_link);
229 		} else {
230 			TAILQ_INSERT_BEFORE(s, r, r_link);
231 		}
232 	}
233 out:
234 	mtx_unlock(rm->rm_mtx);
235 	return rv;
236 }
237 
238 int
239 rman_init_from_resource(struct rman *rm, struct resource *r)
240 {
241 	int rv;
242 
243 	if ((rv = rman_init(rm)) != 0)
244 		return (rv);
245 	return (rman_manage_region(rm, r->__r_i->r_start, r->__r_i->r_end));
246 }
247 
248 int
249 rman_fini(struct rman *rm)
250 {
251 	struct resource_i *r;
252 
253 	mtx_lock(rm->rm_mtx);
254 	TAILQ_FOREACH(r, &rm->rm_list, r_link) {
255 		if (r->r_flags & RF_ALLOCATED) {
256 			mtx_unlock(rm->rm_mtx);
257 			return EBUSY;
258 		}
259 	}
260 
261 	/*
262 	 * There really should only be one of these if we are in this
263 	 * state and the code is working properly, but it can't hurt.
264 	 */
265 	while (!TAILQ_EMPTY(&rm->rm_list)) {
266 		r = TAILQ_FIRST(&rm->rm_list);
267 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
268 		free(r, M_RMAN);
269 	}
270 	mtx_unlock(rm->rm_mtx);
271 	mtx_lock(&rman_mtx);
272 	TAILQ_REMOVE(&rman_head, rm, rm_link);
273 	mtx_unlock(&rman_mtx);
274 	mtx_destroy(rm->rm_mtx);
275 	free(rm->rm_mtx, M_RMAN);
276 
277 	return 0;
278 }
279 
280 int
281 rman_first_free_region(struct rman *rm, u_long *start, u_long *end)
282 {
283 	struct resource_i *r;
284 
285 	mtx_lock(rm->rm_mtx);
286 	TAILQ_FOREACH(r, &rm->rm_list, r_link) {
287 		if (!(r->r_flags & RF_ALLOCATED)) {
288 			*start = r->r_start;
289 			*end = r->r_end;
290 			mtx_unlock(rm->rm_mtx);
291 			return (0);
292 		}
293 	}
294 	mtx_unlock(rm->rm_mtx);
295 	return (ENOENT);
296 }
297 
298 int
299 rman_last_free_region(struct rman *rm, u_long *start, u_long *end)
300 {
301 	struct resource_i *r;
302 
303 	mtx_lock(rm->rm_mtx);
304 	TAILQ_FOREACH_REVERSE(r, &rm->rm_list, resource_head, r_link) {
305 		if (!(r->r_flags & RF_ALLOCATED)) {
306 			*start = r->r_start;
307 			*end = r->r_end;
308 			mtx_unlock(rm->rm_mtx);
309 			return (0);
310 		}
311 	}
312 	mtx_unlock(rm->rm_mtx);
313 	return (ENOENT);
314 }
315 
316 /* Shrink or extend one or both ends of an allocated resource. */
317 int
318 rman_adjust_resource(struct resource *rr, u_long start, u_long end)
319 {
320 	struct	resource_i *r, *s, *t, *new;
321 	struct	rman *rm;
322 
323 	/* Not supported for shared resources. */
324 	r = rr->__r_i;
325 	if (r->r_flags & (RF_TIMESHARE | RF_SHAREABLE))
326 		return (EINVAL);
327 
328 	/*
329 	 * This does not support wholesale moving of a resource.  At
330 	 * least part of the desired new range must overlap with the
331 	 * existing resource.
332 	 */
333 	if (end < r->r_start || r->r_end < start)
334 		return (EINVAL);
335 
336 	/*
337 	 * Find the two resource regions immediately adjacent to the
338 	 * allocated resource.
339 	 */
340 	rm = r->r_rm;
341 	mtx_lock(rm->rm_mtx);
342 #ifdef INVARIANTS
343 	TAILQ_FOREACH(s, &rm->rm_list, r_link) {
344 		if (s == r)
345 			break;
346 	}
347 	if (s == NULL)
348 		panic("resource not in list");
349 #endif
350 	s = TAILQ_PREV(r, resource_head, r_link);
351 	t = TAILQ_NEXT(r, r_link);
352 	KASSERT(s == NULL || s->r_end + 1 == r->r_start,
353 	    ("prev resource mismatch"));
354 	KASSERT(t == NULL || r->r_end + 1 == t->r_start,
355 	    ("next resource mismatch"));
356 
357 	/*
358 	 * See if the changes are permitted.  Shrinking is always allowed,
359 	 * but growing requires sufficient room in the adjacent region.
360 	 */
361 	if (start < r->r_start && (s == NULL || (s->r_flags & RF_ALLOCATED) ||
362 	    s->r_start > start)) {
363 		mtx_unlock(rm->rm_mtx);
364 		return (EBUSY);
365 	}
366 	if (end > r->r_end && (t == NULL || (t->r_flags & RF_ALLOCATED) ||
367 	    t->r_end < end)) {
368 		mtx_unlock(rm->rm_mtx);
369 		return (EBUSY);
370 	}
371 
372 	/*
373 	 * While holding the lock, grow either end of the resource as
374 	 * needed and shrink either end if the shrinking does not require
375 	 * allocating a new resource.  We can safely drop the lock and then
376 	 * insert a new range to handle the shrinking case afterwards.
377 	 */
378 	if (start < r->r_start ||
379 	    (start > r->r_start && s != NULL && !(s->r_flags & RF_ALLOCATED))) {
380 		KASSERT(s->r_flags == 0, ("prev is busy"));
381 		r->r_start = start;
382 		if (s->r_start == start) {
383 			TAILQ_REMOVE(&rm->rm_list, s, r_link);
384 			free(s, M_RMAN);
385 		} else
386 			s->r_end = start - 1;
387 	}
388 	if (end > r->r_end ||
389 	    (end < r->r_end && t != NULL && !(t->r_flags & RF_ALLOCATED))) {
390 		KASSERT(t->r_flags == 0, ("next is busy"));
391 		r->r_end = end;
392 		if (t->r_end == end) {
393 			TAILQ_REMOVE(&rm->rm_list, t, r_link);
394 			free(t, M_RMAN);
395 		} else
396 			t->r_start = end + 1;
397 	}
398 	mtx_unlock(rm->rm_mtx);
399 
400 	/*
401 	 * Handle the shrinking cases that require allocating a new
402 	 * resource to hold the newly-free region.  We have to recheck
403 	 * if we still need this new region after acquiring the lock.
404 	 */
405 	if (start > r->r_start) {
406 		new = int_alloc_resource(M_WAITOK);
407 		new->r_start = r->r_start;
408 		new->r_end = start - 1;
409 		new->r_rm = rm;
410 		mtx_lock(rm->rm_mtx);
411 		r->r_start = start;
412 		s = TAILQ_PREV(r, resource_head, r_link);
413 		if (s != NULL && !(s->r_flags & RF_ALLOCATED)) {
414 			s->r_end = start - 1;
415 			free(new, M_RMAN);
416 		} else
417 			TAILQ_INSERT_BEFORE(r, new, r_link);
418 		mtx_unlock(rm->rm_mtx);
419 	}
420 	if (end < r->r_end) {
421 		new = int_alloc_resource(M_WAITOK);
422 		new->r_start = end + 1;
423 		new->r_end = r->r_end;
424 		new->r_rm = rm;
425 		mtx_lock(rm->rm_mtx);
426 		r->r_end = end;
427 		t = TAILQ_NEXT(r, r_link);
428 		if (t != NULL && !(t->r_flags & RF_ALLOCATED)) {
429 			t->r_start = end + 1;
430 			free(new, M_RMAN);
431 		} else
432 			TAILQ_INSERT_AFTER(&rm->rm_list, r, new, r_link);
433 		mtx_unlock(rm->rm_mtx);
434 	}
435 	return (0);
436 }
437 
438 struct resource *
439 rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
440 		      u_long count, u_long bound,  u_int flags,
441 		      struct device *dev)
442 {
443 	u_int	want_activate;
444 	struct	resource_i *r, *s, *rv;
445 	u_long	rstart, rend, amask, bmask;
446 
447 	rv = NULL;
448 
449 	DPRINTF(("rman_reserve_resource_bound: <%s> request: [%#lx, %#lx], "
450 	       "length %#lx, flags %u, device %s\n", rm->rm_descr, start, end,
451 	       count, flags,
452 	       dev == NULL ? "<null>" : device_get_nameunit(dev)));
453 	want_activate = (flags & RF_ACTIVE);
454 	flags &= ~RF_ACTIVE;
455 
456 	mtx_lock(rm->rm_mtx);
457 
458 	for (r = TAILQ_FIRST(&rm->rm_list);
459 	     r && r->r_end < start + count - 1;
460 	     r = TAILQ_NEXT(r, r_link))
461 		;
462 
463 	if (r == NULL) {
464 		DPRINTF(("could not find a region\n"));
465 		goto out;
466 	}
467 
468 	amask = (1ul << RF_ALIGNMENT(flags)) - 1;
469 	if (start > ULONG_MAX - amask) {
470 		DPRINTF(("start+amask would wrap around\n"));
471 		goto out;
472 	}
473 
474 	/* If bound is 0, bmask will also be 0 */
475 	bmask = ~(bound - 1);
476 	/*
477 	 * First try to find an acceptable totally-unshared region.
478 	 */
479 	for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
480 		DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end));
481 		/*
482 		 * The resource list is sorted, so there is no point in
483 		 * searching further once r_start is too large.
484 		 */
485 		if (s->r_start > end - (count - 1)) {
486 			DPRINTF(("s->r_start (%#lx) + count - 1> end (%#lx)\n",
487 			    s->r_start, end));
488 			break;
489 		}
490 		if (s->r_start > ULONG_MAX - amask) {
491 			DPRINTF(("s->r_start (%#lx) + amask (%#lx) too large\n",
492 			    s->r_start, amask));
493 			break;
494 		}
495 		if (s->r_flags & RF_ALLOCATED) {
496 			DPRINTF(("region is allocated\n"));
497 			continue;
498 		}
499 		rstart = ulmax(s->r_start, start);
500 		/*
501 		 * Try to find a region by adjusting to boundary and alignment
502 		 * until both conditions are satisfied. This is not an optimal
503 		 * algorithm, but in most cases it isn't really bad, either.
504 		 */
505 		do {
506 			rstart = (rstart + amask) & ~amask;
507 			if (((rstart ^ (rstart + count - 1)) & bmask) != 0)
508 				rstart += bound - (rstart & ~bmask);
509 		} while ((rstart & amask) != 0 && rstart < end &&
510 		    rstart < s->r_end);
511 		rend = ulmin(s->r_end, ulmax(rstart + count - 1, end));
512 		if (rstart > rend) {
513 			DPRINTF(("adjusted start exceeds end\n"));
514 			continue;
515 		}
516 		DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
517 		       rstart, rend, (rend - rstart + 1), count));
518 
519 		if ((rend - rstart + 1) >= count) {
520 			DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n",
521 			       rstart, rend, (rend - rstart + 1)));
522 			if ((s->r_end - s->r_start + 1) == count) {
523 				DPRINTF(("candidate region is entire chunk\n"));
524 				rv = s;
525 				rv->r_flags |= RF_ALLOCATED | flags;
526 				rv->r_dev = dev;
527 				goto out;
528 			}
529 
530 			/*
531 			 * If s->r_start < rstart and
532 			 *    s->r_end > rstart + count - 1, then
533 			 * we need to split the region into three pieces
534 			 * (the middle one will get returned to the user).
535 			 * Otherwise, we are allocating at either the
536 			 * beginning or the end of s, so we only need to
537 			 * split it in two.  The first case requires
538 			 * two new allocations; the second requires but one.
539 			 */
540 			rv = int_alloc_resource(M_NOWAIT);
541 			if (rv == NULL)
542 				goto out;
543 			rv->r_start = rstart;
544 			rv->r_end = rstart + count - 1;
545 			rv->r_flags = flags | RF_ALLOCATED;
546 			rv->r_dev = dev;
547 			rv->r_rm = rm;
548 
549 			if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
550 				DPRINTF(("splitting region in three parts: "
551 				       "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n",
552 				       s->r_start, rv->r_start - 1,
553 				       rv->r_start, rv->r_end,
554 				       rv->r_end + 1, s->r_end));
555 				/*
556 				 * We are allocating in the middle.
557 				 */
558 				r = int_alloc_resource(M_NOWAIT);
559 				if (r == NULL) {
560 					free(rv, M_RMAN);
561 					rv = NULL;
562 					goto out;
563 				}
564 				r->r_start = rv->r_end + 1;
565 				r->r_end = s->r_end;
566 				r->r_flags = s->r_flags;
567 				r->r_rm = rm;
568 				s->r_end = rv->r_start - 1;
569 				TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
570 						     r_link);
571 				TAILQ_INSERT_AFTER(&rm->rm_list, rv, r,
572 						     r_link);
573 			} else if (s->r_start == rv->r_start) {
574 				DPRINTF(("allocating from the beginning\n"));
575 				/*
576 				 * We are allocating at the beginning.
577 				 */
578 				s->r_start = rv->r_end + 1;
579 				TAILQ_INSERT_BEFORE(s, rv, r_link);
580 			} else {
581 				DPRINTF(("allocating at the end\n"));
582 				/*
583 				 * We are allocating at the end.
584 				 */
585 				s->r_end = rv->r_start - 1;
586 				TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
587 						     r_link);
588 			}
589 			goto out;
590 		}
591 	}
592 
593 	/*
594 	 * Now find an acceptable shared region, if the client's requirements
595 	 * allow sharing.  By our implementation restriction, a candidate
596 	 * region must match exactly by both size and sharing type in order
597 	 * to be considered compatible with the client's request.  (The
598 	 * former restriction could probably be lifted without too much
599 	 * additional work, but this does not seem warranted.)
600 	 */
601 	DPRINTF(("no unshared regions found\n"));
602 	if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
603 		goto out;
604 
605 	for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
606 		if (s->r_start > end)
607 			break;
608 		if ((s->r_flags & flags) != flags)
609 			continue;
610 		if (s->r_start >= start && s->r_end <= end
611 		    && (s->r_end - s->r_start + 1) == count &&
612 		    (s->r_start & amask) == 0 &&
613 		    ((s->r_start ^ s->r_end) & bmask) == 0) {
614 			rv = int_alloc_resource(M_NOWAIT);
615 			if (rv == NULL)
616 				goto out;
617 			rv->r_start = s->r_start;
618 			rv->r_end = s->r_end;
619 			rv->r_flags = s->r_flags &
620 				(RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
621 			rv->r_dev = dev;
622 			rv->r_rm = rm;
623 			if (s->r_sharehead == NULL) {
624 				s->r_sharehead = malloc(sizeof *s->r_sharehead,
625 						M_RMAN, M_NOWAIT | M_ZERO);
626 				if (s->r_sharehead == NULL) {
627 					free(rv, M_RMAN);
628 					rv = NULL;
629 					goto out;
630 				}
631 				LIST_INIT(s->r_sharehead);
632 				LIST_INSERT_HEAD(s->r_sharehead, s,
633 						 r_sharelink);
634 				s->r_flags |= RF_FIRSTSHARE;
635 			}
636 			rv->r_sharehead = s->r_sharehead;
637 			LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
638 			goto out;
639 		}
640 	}
641 
642 	/*
643 	 * We couldn't find anything.
644 	 */
645 out:
646 	/*
647 	 * If the user specified RF_ACTIVE in the initial flags,
648 	 * which is reflected in `want_activate', we attempt to atomically
649 	 * activate the resource.  If this fails, we release the resource
650 	 * and indicate overall failure.  (This behavior probably doesn't
651 	 * make sense for RF_TIMESHARE-type resources.)
652 	 */
653 	if (rv && want_activate) {
654 		struct resource_i *whohas;
655 		if (int_rman_activate_resource(rm, rv, &whohas)) {
656 			int_rman_release_resource(rm, rv);
657 			rv = NULL;
658 		}
659 	}
660 
661 	mtx_unlock(rm->rm_mtx);
662 	return (rv == NULL ? NULL : &rv->r_r);
663 }
664 
665 struct resource *
666 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
667 		      u_int flags, struct device *dev)
668 {
669 
670 	return (rman_reserve_resource_bound(rm, start, end, count, 0, flags,
671 	    dev));
672 }
673 
674 static int
675 int_rman_activate_resource(struct rman *rm, struct resource_i *r,
676 			   struct resource_i **whohas)
677 {
678 	struct resource_i *s;
679 	int ok;
680 
681 	/*
682 	 * If we are not timesharing, then there is nothing much to do.
683 	 * If we already have the resource, then there is nothing at all to do.
684 	 * If we are not on a sharing list with anybody else, then there is
685 	 * little to do.
686 	 */
687 	if ((r->r_flags & RF_TIMESHARE) == 0
688 	    || (r->r_flags & RF_ACTIVE) != 0
689 	    || r->r_sharehead == NULL) {
690 		r->r_flags |= RF_ACTIVE;
691 		return 0;
692 	}
693 
694 	ok = 1;
695 	for (s = LIST_FIRST(r->r_sharehead); s && ok;
696 	     s = LIST_NEXT(s, r_sharelink)) {
697 		if ((s->r_flags & RF_ACTIVE) != 0) {
698 			ok = 0;
699 			*whohas = s;
700 		}
701 	}
702 	if (ok) {
703 		r->r_flags |= RF_ACTIVE;
704 		return 0;
705 	}
706 	return EBUSY;
707 }
708 
709 int
710 rman_activate_resource(struct resource *re)
711 {
712 	int rv;
713 	struct resource_i *r, *whohas;
714 	struct rman *rm;
715 
716 	r = re->__r_i;
717 	rm = r->r_rm;
718 	mtx_lock(rm->rm_mtx);
719 	rv = int_rman_activate_resource(rm, r, &whohas);
720 	mtx_unlock(rm->rm_mtx);
721 	return rv;
722 }
723 
724 int
725 rman_await_resource(struct resource *re, int pri, int timo)
726 {
727 	int	rv;
728 	struct	resource_i *r, *whohas;
729 	struct	rman *rm;
730 
731 	r = re->__r_i;
732 	rm = r->r_rm;
733 	mtx_lock(rm->rm_mtx);
734 	for (;;) {
735 		rv = int_rman_activate_resource(rm, r, &whohas);
736 		if (rv != EBUSY)
737 			return (rv);	/* returns with mutex held */
738 
739 		if (r->r_sharehead == NULL)
740 			panic("rman_await_resource");
741 		whohas->r_flags |= RF_WANTED;
742 		rv = msleep(r->r_sharehead, rm->rm_mtx, pri, "rmwait", timo);
743 		if (rv) {
744 			mtx_unlock(rm->rm_mtx);
745 			return (rv);
746 		}
747 	}
748 }
749 
750 static int
751 int_rman_deactivate_resource(struct resource_i *r)
752 {
753 
754 	r->r_flags &= ~RF_ACTIVE;
755 	if (r->r_flags & RF_WANTED) {
756 		r->r_flags &= ~RF_WANTED;
757 		wakeup(r->r_sharehead);
758 	}
759 	return 0;
760 }
761 
762 int
763 rman_deactivate_resource(struct resource *r)
764 {
765 	struct	rman *rm;
766 
767 	rm = r->__r_i->r_rm;
768 	mtx_lock(rm->rm_mtx);
769 	int_rman_deactivate_resource(r->__r_i);
770 	mtx_unlock(rm->rm_mtx);
771 	return 0;
772 }
773 
774 static int
775 int_rman_release_resource(struct rman *rm, struct resource_i *r)
776 {
777 	struct	resource_i *s, *t;
778 
779 	if (r->r_flags & RF_ACTIVE)
780 		int_rman_deactivate_resource(r);
781 
782 	/*
783 	 * Check for a sharing list first.  If there is one, then we don't
784 	 * have to think as hard.
785 	 */
786 	if (r->r_sharehead) {
787 		/*
788 		 * If a sharing list exists, then we know there are at
789 		 * least two sharers.
790 		 *
791 		 * If we are in the main circleq, appoint someone else.
792 		 */
793 		LIST_REMOVE(r, r_sharelink);
794 		s = LIST_FIRST(r->r_sharehead);
795 		if (r->r_flags & RF_FIRSTSHARE) {
796 			s->r_flags |= RF_FIRSTSHARE;
797 			TAILQ_INSERT_BEFORE(r, s, r_link);
798 			TAILQ_REMOVE(&rm->rm_list, r, r_link);
799 		}
800 
801 		/*
802 		 * Make sure that the sharing list goes away completely
803 		 * if the resource is no longer being shared at all.
804 		 */
805 		if (LIST_NEXT(s, r_sharelink) == NULL) {
806 			free(s->r_sharehead, M_RMAN);
807 			s->r_sharehead = NULL;
808 			s->r_flags &= ~RF_FIRSTSHARE;
809 		}
810 		goto out;
811 	}
812 
813 	/*
814 	 * Look at the adjacent resources in the list and see if our
815 	 * segment can be merged with any of them.  If either of the
816 	 * resources is allocated or is not exactly adjacent then they
817 	 * cannot be merged with our segment.
818 	 */
819 	s = TAILQ_PREV(r, resource_head, r_link);
820 	if (s != NULL && ((s->r_flags & RF_ALLOCATED) != 0 ||
821 	    s->r_end + 1 != r->r_start))
822 		s = NULL;
823 	t = TAILQ_NEXT(r, r_link);
824 	if (t != NULL && ((t->r_flags & RF_ALLOCATED) != 0 ||
825 	    r->r_end + 1 != t->r_start))
826 		t = NULL;
827 
828 	if (s != NULL && t != NULL) {
829 		/*
830 		 * Merge all three segments.
831 		 */
832 		s->r_end = t->r_end;
833 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
834 		TAILQ_REMOVE(&rm->rm_list, t, r_link);
835 		free(t, M_RMAN);
836 	} else if (s != NULL) {
837 		/*
838 		 * Merge previous segment with ours.
839 		 */
840 		s->r_end = r->r_end;
841 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
842 	} else if (t != NULL) {
843 		/*
844 		 * Merge next segment with ours.
845 		 */
846 		t->r_start = r->r_start;
847 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
848 	} else {
849 		/*
850 		 * At this point, we know there is nothing we
851 		 * can potentially merge with, because on each
852 		 * side, there is either nothing there or what is
853 		 * there is still allocated.  In that case, we don't
854 		 * want to remove r from the list; we simply want to
855 		 * change it to an unallocated region and return
856 		 * without freeing anything.
857 		 */
858 		r->r_flags &= ~RF_ALLOCATED;
859 		r->r_dev = NULL;
860 		return 0;
861 	}
862 
863 out:
864 	free(r, M_RMAN);
865 	return 0;
866 }
867 
868 int
869 rman_release_resource(struct resource *re)
870 {
871 	int	rv;
872 	struct	resource_i *r;
873 	struct	rman *rm;
874 
875 	r = re->__r_i;
876 	rm = r->r_rm;
877 	mtx_lock(rm->rm_mtx);
878 	rv = int_rman_release_resource(rm, r);
879 	mtx_unlock(rm->rm_mtx);
880 	return (rv);
881 }
882 
883 uint32_t
884 rman_make_alignment_flags(uint32_t size)
885 {
886 	int	i;
887 
888 	/*
889 	 * Find the hightest bit set, and add one if more than one bit
890 	 * set.  We're effectively computing the ceil(log2(size)) here.
891 	 */
892 	for (i = 31; i > 0; i--)
893 		if ((1 << i) & size)
894 			break;
895 	if (~(1 << i) & size)
896 		i++;
897 
898 	return(RF_ALIGNMENT_LOG2(i));
899 }
900 
901 void
902 rman_set_start(struct resource *r, u_long start)
903 {
904 	r->__r_i->r_start = start;
905 }
906 
907 u_long
908 rman_get_start(struct resource *r)
909 {
910 	return (r->__r_i->r_start);
911 }
912 
913 void
914 rman_set_end(struct resource *r, u_long end)
915 {
916 	r->__r_i->r_end = end;
917 }
918 
919 u_long
920 rman_get_end(struct resource *r)
921 {
922 	return (r->__r_i->r_end);
923 }
924 
925 u_long
926 rman_get_size(struct resource *r)
927 {
928 	return (r->__r_i->r_end - r->__r_i->r_start + 1);
929 }
930 
931 u_int
932 rman_get_flags(struct resource *r)
933 {
934 	return (r->__r_i->r_flags);
935 }
936 
937 void
938 rman_set_virtual(struct resource *r, void *v)
939 {
940 	r->__r_i->r_virtual = v;
941 }
942 
943 void *
944 rman_get_virtual(struct resource *r)
945 {
946 	return (r->__r_i->r_virtual);
947 }
948 
949 void
950 rman_set_bustag(struct resource *r, bus_space_tag_t t)
951 {
952 	r->r_bustag = t;
953 }
954 
955 bus_space_tag_t
956 rman_get_bustag(struct resource *r)
957 {
958 	return (r->r_bustag);
959 }
960 
961 void
962 rman_set_bushandle(struct resource *r, bus_space_handle_t h)
963 {
964 	r->r_bushandle = h;
965 }
966 
967 bus_space_handle_t
968 rman_get_bushandle(struct resource *r)
969 {
970 	return (r->r_bushandle);
971 }
972 
973 void
974 rman_set_rid(struct resource *r, int rid)
975 {
976 	r->__r_i->r_rid = rid;
977 }
978 
979 int
980 rman_get_rid(struct resource *r)
981 {
982 	return (r->__r_i->r_rid);
983 }
984 
985 void
986 rman_set_device(struct resource *r, struct device *dev)
987 {
988 	r->__r_i->r_dev = dev;
989 }
990 
991 struct device *
992 rman_get_device(struct resource *r)
993 {
994 	return (r->__r_i->r_dev);
995 }
996 
997 int
998 rman_is_region_manager(struct resource *r, struct rman *rm)
999 {
1000 
1001 	return (r->__r_i->r_rm == rm);
1002 }
1003 
1004 /*
1005  * Sysctl interface for scanning the resource lists.
1006  *
1007  * We take two input parameters; the index into the list of resource
1008  * managers, and the resource offset into the list.
1009  */
1010 static int
1011 sysctl_rman(SYSCTL_HANDLER_ARGS)
1012 {
1013 	int			*name = (int *)arg1;
1014 	u_int			namelen = arg2;
1015 	int			rman_idx, res_idx;
1016 	struct rman		*rm;
1017 	struct resource_i	*res;
1018 	struct resource_i	*sres;
1019 	struct u_rman		urm;
1020 	struct u_resource	ures;
1021 	int			error;
1022 
1023 	if (namelen != 3)
1024 		return (EINVAL);
1025 
1026 	if (bus_data_generation_check(name[0]))
1027 		return (EINVAL);
1028 	rman_idx = name[1];
1029 	res_idx = name[2];
1030 
1031 	/*
1032 	 * Find the indexed resource manager
1033 	 */
1034 	mtx_lock(&rman_mtx);
1035 	TAILQ_FOREACH(rm, &rman_head, rm_link) {
1036 		if (rman_idx-- == 0)
1037 			break;
1038 	}
1039 	mtx_unlock(&rman_mtx);
1040 	if (rm == NULL)
1041 		return (ENOENT);
1042 
1043 	/*
1044 	 * If the resource index is -1, we want details on the
1045 	 * resource manager.
1046 	 */
1047 	if (res_idx == -1) {
1048 		bzero(&urm, sizeof(urm));
1049 		urm.rm_handle = (uintptr_t)rm;
1050 		if (rm->rm_descr != NULL)
1051 			strlcpy(urm.rm_descr, rm->rm_descr, RM_TEXTLEN);
1052 		urm.rm_start = rm->rm_start;
1053 		urm.rm_size = rm->rm_end - rm->rm_start + 1;
1054 		urm.rm_type = rm->rm_type;
1055 
1056 		error = SYSCTL_OUT(req, &urm, sizeof(urm));
1057 		return (error);
1058 	}
1059 
1060 	/*
1061 	 * Find the indexed resource and return it.
1062 	 */
1063 	mtx_lock(rm->rm_mtx);
1064 	TAILQ_FOREACH(res, &rm->rm_list, r_link) {
1065 		if (res->r_sharehead != NULL) {
1066 			LIST_FOREACH(sres, res->r_sharehead, r_sharelink)
1067 				if (res_idx-- == 0) {
1068 					res = sres;
1069 					goto found;
1070 				}
1071 		}
1072 		else if (res_idx-- == 0)
1073 				goto found;
1074 	}
1075 	mtx_unlock(rm->rm_mtx);
1076 	return (ENOENT);
1077 
1078 found:
1079 	bzero(&ures, sizeof(ures));
1080 	ures.r_handle = (uintptr_t)res;
1081 	ures.r_parent = (uintptr_t)res->r_rm;
1082 	ures.r_device = (uintptr_t)res->r_dev;
1083 	if (res->r_dev != NULL) {
1084 		if (device_get_name(res->r_dev) != NULL) {
1085 			snprintf(ures.r_devname, RM_TEXTLEN,
1086 			    "%s%d",
1087 			    device_get_name(res->r_dev),
1088 			    device_get_unit(res->r_dev));
1089 		} else {
1090 			strlcpy(ures.r_devname, "nomatch",
1091 			    RM_TEXTLEN);
1092 		}
1093 	} else {
1094 		ures.r_devname[0] = '\0';
1095 	}
1096 	ures.r_start = res->r_start;
1097 	ures.r_size = res->r_end - res->r_start + 1;
1098 	ures.r_flags = res->r_flags;
1099 
1100 	mtx_unlock(rm->rm_mtx);
1101 	error = SYSCTL_OUT(req, &ures, sizeof(ures));
1102 	return (error);
1103 }
1104 
1105 static SYSCTL_NODE(_hw_bus, OID_AUTO, rman, CTLFLAG_RD, sysctl_rman,
1106     "kernel resource manager");
1107 
1108 #ifdef DDB
1109 static void
1110 dump_rman_header(struct rman *rm)
1111 {
1112 
1113 	if (db_pager_quit)
1114 		return;
1115 	db_printf("rman %p: %s (0x%lx-0x%lx full range)\n",
1116 	    rm, rm->rm_descr, rm->rm_start, rm->rm_end);
1117 }
1118 
1119 static void
1120 dump_rman(struct rman *rm)
1121 {
1122 	struct resource_i *r;
1123 	const char *devname;
1124 
1125 	if (db_pager_quit)
1126 		return;
1127 	TAILQ_FOREACH(r, &rm->rm_list, r_link) {
1128 		if (r->r_dev != NULL) {
1129 			devname = device_get_nameunit(r->r_dev);
1130 			if (devname == NULL)
1131 				devname = "nomatch";
1132 		} else
1133 			devname = NULL;
1134 		db_printf("    0x%lx-0x%lx ", r->r_start, r->r_end);
1135 		if (devname != NULL)
1136 			db_printf("(%s)\n", devname);
1137 		else
1138 			db_printf("----\n");
1139 		if (db_pager_quit)
1140 			return;
1141 	}
1142 }
1143 
1144 DB_SHOW_COMMAND(rman, db_show_rman)
1145 {
1146 
1147 	if (have_addr) {
1148 		dump_rman_header((struct rman *)addr);
1149 		dump_rman((struct rman *)addr);
1150 	}
1151 }
1152 
1153 DB_SHOW_COMMAND(rmans, db_show_rmans)
1154 {
1155 	struct rman *rm;
1156 
1157 	TAILQ_FOREACH(rm, &rman_head, rm_link) {
1158 		dump_rman_header(rm);
1159 	}
1160 }
1161 
1162 DB_SHOW_ALL_COMMAND(rman, db_show_all_rman)
1163 {
1164 	struct rman *rm;
1165 
1166 	TAILQ_FOREACH(rm, &rman_head, rm_link) {
1167 		dump_rman_header(rm);
1168 		dump_rman(rm);
1169 	}
1170 }
1171 DB_SHOW_ALIAS(allrman, db_show_all_rman);
1172 #endif
1173