xref: /freebsd/sys/kern/subr_rman.c (revision e4e9813eb92cd7c4d4b819a8fbed5cbd3d92f5d8)
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 <sys/cdefs.h>
59 __FBSDID("$FreeBSD$");
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/mutex.h>
67 #include <sys/bus.h>		/* XXX debugging */
68 #include <machine/bus.h>
69 #include <sys/rman.h>
70 #include <sys/sysctl.h>
71 
72 /*
73  * We use a linked list rather than a bitmap because we need to be able to
74  * represent potentially huge objects (like all of a processor's physical
75  * address space).  That is also why the indices are defined to have type
76  * `unsigned long' -- that being the largest integral type in ISO C (1990).
77  * The 1999 version of C allows `long long'; we may need to switch to that
78  * at some point in the future, particularly if we want to support 36-bit
79  * addresses on IA32 hardware.
80  */
81 struct resource_i {
82 	struct resource		r_r;
83 	TAILQ_ENTRY(resource_i)	r_link;
84 	LIST_ENTRY(resource_i)	r_sharelink;
85 	LIST_HEAD(, resource_i)	*r_sharehead;
86 	u_long	r_start;	/* index of the first entry in this resource */
87 	u_long	r_end;		/* index of the last entry (inclusive) */
88 	u_int	r_flags;
89 	void	*r_virtual;	/* virtual address of this resource */
90 	struct	device *r_dev;	/* device which has allocated this resource */
91 	struct	rman *r_rm;	/* resource manager from whence this came */
92 	int	r_rid;		/* optional rid for this resource. */
93 };
94 
95 int     rman_debug = 0;
96 TUNABLE_INT("debug.rman_debug", &rman_debug);
97 SYSCTL_INT(_debug, OID_AUTO, rman_debug, CTLFLAG_RW,
98     &rman_debug, 0, "rman debug");
99 
100 #define DPRINTF(params) if (rman_debug) printf params
101 
102 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
103 
104 struct	rman_head rman_head;
105 static	struct mtx rman_mtx; /* mutex to protect rman_head */
106 static	int int_rman_activate_resource(struct rman *rm, struct resource_i *r,
107 				       struct resource_i **whohas);
108 static	int int_rman_deactivate_resource(struct resource_i *r);
109 static	int int_rman_release_resource(struct rman *rm, struct resource_i *r);
110 
111 static __inline struct resource_i *
112 int_alloc_resource(int malloc_flag)
113 {
114 	struct resource_i *r;
115 
116 	r = malloc(sizeof *r, M_RMAN, malloc_flag | M_ZERO);
117 	if (r != NULL) {
118 		r->r_r.__r_i = r;
119 	}
120 	return (r);
121 }
122 
123 int
124 rman_init(struct rman *rm)
125 {
126 	static int once = 0;
127 
128 	if (once == 0) {
129 		once = 1;
130 		TAILQ_INIT(&rman_head);
131 		mtx_init(&rman_mtx, "rman head", NULL, MTX_DEF);
132 	}
133 
134 	if (rm->rm_type == RMAN_UNINIT)
135 		panic("rman_init");
136 	if (rm->rm_type == RMAN_GAUGE)
137 		panic("implement RMAN_GAUGE");
138 
139 	TAILQ_INIT(&rm->rm_list);
140 	rm->rm_mtx = malloc(sizeof *rm->rm_mtx, M_RMAN, M_NOWAIT | M_ZERO);
141 	if (rm->rm_mtx == NULL)
142 		return ENOMEM;
143 	mtx_init(rm->rm_mtx, "rman", NULL, MTX_DEF);
144 
145 	mtx_lock(&rman_mtx);
146 	TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
147 	mtx_unlock(&rman_mtx);
148 	return 0;
149 }
150 
151 /*
152  * NB: this interface is not robust against programming errors which
153  * add multiple copies of the same region.
154  */
155 int
156 rman_manage_region(struct rman *rm, u_long start, u_long end)
157 {
158 	struct resource_i *r, *s;
159 
160 	DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
161 	    rm->rm_descr, start, end));
162 	r = int_alloc_resource(M_NOWAIT);
163 	if (r == NULL)
164 		return ENOMEM;
165 	r->r_start = start;
166 	r->r_end = end;
167 	r->r_rm = rm;
168 
169 	mtx_lock(rm->rm_mtx);
170 	for (s = TAILQ_FIRST(&rm->rm_list);
171 	     s && s->r_end < r->r_start;
172 	     s = TAILQ_NEXT(s, r_link))
173 		;
174 
175 	if (s == NULL) {
176 		TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link);
177 	} else {
178 		TAILQ_INSERT_BEFORE(s, r, r_link);
179 	}
180 
181 	mtx_unlock(rm->rm_mtx);
182 	return 0;
183 }
184 
185 int
186 rman_init_from_resource(struct rman *rm, struct resource *r)
187 {
188 	int rv;
189 
190 	if ((rv = rman_init(rm)) != 0)
191 		return (rv);
192 	return (rman_manage_region(rm, r->__r_i->r_start, r->__r_i->r_end));
193 }
194 
195 int
196 rman_fini(struct rman *rm)
197 {
198 	struct resource_i *r;
199 
200 	mtx_lock(rm->rm_mtx);
201 	TAILQ_FOREACH(r, &rm->rm_list, r_link) {
202 		if (r->r_flags & RF_ALLOCATED) {
203 			mtx_unlock(rm->rm_mtx);
204 			return EBUSY;
205 		}
206 	}
207 
208 	/*
209 	 * There really should only be one of these if we are in this
210 	 * state and the code is working properly, but it can't hurt.
211 	 */
212 	while (!TAILQ_EMPTY(&rm->rm_list)) {
213 		r = TAILQ_FIRST(&rm->rm_list);
214 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
215 		free(r, M_RMAN);
216 	}
217 	mtx_unlock(rm->rm_mtx);
218 	mtx_lock(&rman_mtx);
219 	TAILQ_REMOVE(&rman_head, rm, rm_link);
220 	mtx_unlock(&rman_mtx);
221 	mtx_destroy(rm->rm_mtx);
222 	free(rm->rm_mtx, M_RMAN);
223 
224 	return 0;
225 }
226 
227 struct resource *
228 rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
229 		      u_long count, u_long bound,  u_int flags,
230 		      struct device *dev)
231 {
232 	u_int	want_activate;
233 	struct	resource_i *r, *s, *rv;
234 	u_long	rstart, rend, amask, bmask;
235 
236 	rv = NULL;
237 
238 	DPRINTF(("rman_reserve_resource_bound: <%s> request: [%#lx, %#lx], "
239 	       "length %#lx, flags %u, device %s\n", rm->rm_descr, start, end,
240 	       count, flags,
241 	       dev == NULL ? "<null>" : device_get_nameunit(dev)));
242 	want_activate = (flags & RF_ACTIVE);
243 	flags &= ~RF_ACTIVE;
244 
245 	mtx_lock(rm->rm_mtx);
246 
247 	for (r = TAILQ_FIRST(&rm->rm_list);
248 	     r && r->r_end < start;
249 	     r = TAILQ_NEXT(r, r_link))
250 		;
251 
252 	if (r == NULL) {
253 		DPRINTF(("could not find a region\n"));
254 		goto out;
255 	}
256 
257 	amask = (1ul << RF_ALIGNMENT(flags)) - 1;
258 	/* If bound is 0, bmask will also be 0 */
259 	bmask = ~(bound - 1);
260 	/*
261 	 * First try to find an acceptable totally-unshared region.
262 	 */
263 	for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
264 		DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end));
265 		if (s->r_start + count - 1 > end) {
266 			DPRINTF(("s->r_start (%#lx) + count - 1> end (%#lx)\n",
267 			    s->r_start, end));
268 			break;
269 		}
270 		if (s->r_flags & RF_ALLOCATED) {
271 			DPRINTF(("region is allocated\n"));
272 			continue;
273 		}
274 		rstart = ulmax(s->r_start, start);
275 		/*
276 		 * Try to find a region by adjusting to boundary and alignment
277 		 * until both conditions are satisfied. This is not an optimal
278 		 * algorithm, but in most cases it isn't really bad, either.
279 		 */
280 		do {
281 			rstart = (rstart + amask) & ~amask;
282 			if (((rstart ^ (rstart + count - 1)) & bmask) != 0)
283 				rstart += bound - (rstart & ~bmask);
284 		} while ((rstart & amask) != 0 && rstart < end &&
285 		    rstart < s->r_end);
286 		rend = ulmin(s->r_end, ulmax(rstart + count - 1, end));
287 		if (rstart > rend) {
288 			DPRINTF(("adjusted start exceeds end\n"));
289 			continue;
290 		}
291 		DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
292 		       rstart, rend, (rend - rstart + 1), count));
293 
294 		if ((rend - rstart + 1) >= count) {
295 			DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n",
296 			       rstart, rend, (rend - rstart + 1)));
297 			if ((s->r_end - s->r_start + 1) == count) {
298 				DPRINTF(("candidate region is entire chunk\n"));
299 				rv = s;
300 				rv->r_flags |= RF_ALLOCATED | flags;
301 				rv->r_dev = dev;
302 				goto out;
303 			}
304 
305 			/*
306 			 * If s->r_start < rstart and
307 			 *    s->r_end > rstart + count - 1, then
308 			 * we need to split the region into three pieces
309 			 * (the middle one will get returned to the user).
310 			 * Otherwise, we are allocating at either the
311 			 * beginning or the end of s, so we only need to
312 			 * split it in two.  The first case requires
313 			 * two new allocations; the second requires but one.
314 			 */
315 			rv = int_alloc_resource(M_NOWAIT);
316 			if (rv == NULL)
317 				goto out;
318 			rv->r_start = rstart;
319 			rv->r_end = rstart + count - 1;
320 			rv->r_flags = flags | RF_ALLOCATED;
321 			rv->r_dev = dev;
322 			rv->r_rm = rm;
323 
324 			if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
325 				DPRINTF(("splitting region in three parts: "
326 				       "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n",
327 				       s->r_start, rv->r_start - 1,
328 				       rv->r_start, rv->r_end,
329 				       rv->r_end + 1, s->r_end));
330 				/*
331 				 * We are allocating in the middle.
332 				 */
333 				r = int_alloc_resource(M_NOWAIT);
334 				if (r == NULL) {
335 					free(rv, M_RMAN);
336 					rv = NULL;
337 					goto out;
338 				}
339 				r->r_start = rv->r_end + 1;
340 				r->r_end = s->r_end;
341 				r->r_flags = s->r_flags;
342 				r->r_rm = rm;
343 				s->r_end = rv->r_start - 1;
344 				TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
345 						     r_link);
346 				TAILQ_INSERT_AFTER(&rm->rm_list, rv, r,
347 						     r_link);
348 			} else if (s->r_start == rv->r_start) {
349 				DPRINTF(("allocating from the beginning\n"));
350 				/*
351 				 * We are allocating at the beginning.
352 				 */
353 				s->r_start = rv->r_end + 1;
354 				TAILQ_INSERT_BEFORE(s, rv, r_link);
355 			} else {
356 				DPRINTF(("allocating at the end\n"));
357 				/*
358 				 * We are allocating at the end.
359 				 */
360 				s->r_end = rv->r_start - 1;
361 				TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
362 						     r_link);
363 			}
364 			goto out;
365 		}
366 	}
367 
368 	/*
369 	 * Now find an acceptable shared region, if the client's requirements
370 	 * allow sharing.  By our implementation restriction, a candidate
371 	 * region must match exactly by both size and sharing type in order
372 	 * to be considered compatible with the client's request.  (The
373 	 * former restriction could probably be lifted without too much
374 	 * additional work, but this does not seem warranted.)
375 	 */
376 	DPRINTF(("no unshared regions found\n"));
377 	if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
378 		goto out;
379 
380 	for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
381 		if (s->r_start > end)
382 			break;
383 		if ((s->r_flags & flags) != flags)
384 			continue;
385 		rstart = ulmax(s->r_start, start);
386 		rend = ulmin(s->r_end, ulmax(start + count - 1, end));
387 		if (s->r_start >= start && s->r_end <= end
388 		    && (s->r_end - s->r_start + 1) == count &&
389 		    (s->r_start & amask) == 0 &&
390 		    ((s->r_start ^ s->r_end) & bmask) == 0) {
391 			rv = int_alloc_resource(M_NOWAIT);
392 			if (rv == NULL)
393 				goto out;
394 			rv->r_start = s->r_start;
395 			rv->r_end = s->r_end;
396 			rv->r_flags = s->r_flags &
397 				(RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
398 			rv->r_dev = dev;
399 			rv->r_rm = rm;
400 			if (s->r_sharehead == NULL) {
401 				s->r_sharehead = malloc(sizeof *s->r_sharehead,
402 						M_RMAN, M_NOWAIT | M_ZERO);
403 				if (s->r_sharehead == NULL) {
404 					free(rv, M_RMAN);
405 					rv = NULL;
406 					goto out;
407 				}
408 				LIST_INIT(s->r_sharehead);
409 				LIST_INSERT_HEAD(s->r_sharehead, s,
410 						 r_sharelink);
411 				s->r_flags |= RF_FIRSTSHARE;
412 			}
413 			rv->r_sharehead = s->r_sharehead;
414 			LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
415 			goto out;
416 		}
417 	}
418 
419 	/*
420 	 * We couldn't find anything.
421 	 */
422 out:
423 	/*
424 	 * If the user specified RF_ACTIVE in the initial flags,
425 	 * which is reflected in `want_activate', we attempt to atomically
426 	 * activate the resource.  If this fails, we release the resource
427 	 * and indicate overall failure.  (This behavior probably doesn't
428 	 * make sense for RF_TIMESHARE-type resources.)
429 	 */
430 	if (rv && want_activate) {
431 		struct resource_i *whohas;
432 		if (int_rman_activate_resource(rm, rv, &whohas)) {
433 			int_rman_release_resource(rm, rv);
434 			rv = NULL;
435 		}
436 	}
437 
438 	mtx_unlock(rm->rm_mtx);
439 	return (rv == NULL ? NULL : &rv->r_r);
440 }
441 
442 struct resource *
443 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
444 		      u_int flags, struct device *dev)
445 {
446 
447 	return (rman_reserve_resource_bound(rm, start, end, count, 0, flags,
448 	    dev));
449 }
450 
451 static int
452 int_rman_activate_resource(struct rman *rm, struct resource_i *r,
453 			   struct resource_i **whohas)
454 {
455 	struct resource_i *s;
456 	int ok;
457 
458 	/*
459 	 * If we are not timesharing, then there is nothing much to do.
460 	 * If we already have the resource, then there is nothing at all to do.
461 	 * If we are not on a sharing list with anybody else, then there is
462 	 * little to do.
463 	 */
464 	if ((r->r_flags & RF_TIMESHARE) == 0
465 	    || (r->r_flags & RF_ACTIVE) != 0
466 	    || r->r_sharehead == NULL) {
467 		r->r_flags |= RF_ACTIVE;
468 		return 0;
469 	}
470 
471 	ok = 1;
472 	for (s = LIST_FIRST(r->r_sharehead); s && ok;
473 	     s = LIST_NEXT(s, r_sharelink)) {
474 		if ((s->r_flags & RF_ACTIVE) != 0) {
475 			ok = 0;
476 			*whohas = s;
477 		}
478 	}
479 	if (ok) {
480 		r->r_flags |= RF_ACTIVE;
481 		return 0;
482 	}
483 	return EBUSY;
484 }
485 
486 int
487 rman_activate_resource(struct resource *re)
488 {
489 	int rv;
490 	struct resource_i *r, *whohas;
491 	struct rman *rm;
492 
493 	r = re->__r_i;
494 	rm = r->r_rm;
495 	mtx_lock(rm->rm_mtx);
496 	rv = int_rman_activate_resource(rm, r, &whohas);
497 	mtx_unlock(rm->rm_mtx);
498 	return rv;
499 }
500 
501 int
502 rman_await_resource(struct resource *re, int pri, int timo)
503 {
504 	int	rv;
505 	struct	resource_i *r, *whohas;
506 	struct	rman *rm;
507 
508 	r = re->__r_i;
509 	rm = r->r_rm;
510 	mtx_lock(rm->rm_mtx);
511 	for (;;) {
512 		rv = int_rman_activate_resource(rm, r, &whohas);
513 		if (rv != EBUSY)
514 			return (rv);	/* returns with mutex held */
515 
516 		if (r->r_sharehead == NULL)
517 			panic("rman_await_resource");
518 		whohas->r_flags |= RF_WANTED;
519 		rv = msleep(r->r_sharehead, rm->rm_mtx, pri, "rmwait", timo);
520 		if (rv) {
521 			mtx_unlock(rm->rm_mtx);
522 			return (rv);
523 		}
524 	}
525 }
526 
527 static int
528 int_rman_deactivate_resource(struct resource_i *r)
529 {
530 
531 	r->r_flags &= ~RF_ACTIVE;
532 	if (r->r_flags & RF_WANTED) {
533 		r->r_flags &= ~RF_WANTED;
534 		wakeup(r->r_sharehead);
535 	}
536 	return 0;
537 }
538 
539 int
540 rman_deactivate_resource(struct resource *r)
541 {
542 	struct	rman *rm;
543 
544 	rm = r->__r_i->r_rm;
545 	mtx_lock(rm->rm_mtx);
546 	int_rman_deactivate_resource(r->__r_i);
547 	mtx_unlock(rm->rm_mtx);
548 	return 0;
549 }
550 
551 static int
552 int_rman_release_resource(struct rman *rm, struct resource_i *r)
553 {
554 	struct	resource_i *s, *t;
555 
556 	if (r->r_flags & RF_ACTIVE)
557 		int_rman_deactivate_resource(r);
558 
559 	/*
560 	 * Check for a sharing list first.  If there is one, then we don't
561 	 * have to think as hard.
562 	 */
563 	if (r->r_sharehead) {
564 		/*
565 		 * If a sharing list exists, then we know there are at
566 		 * least two sharers.
567 		 *
568 		 * If we are in the main circleq, appoint someone else.
569 		 */
570 		LIST_REMOVE(r, r_sharelink);
571 		s = LIST_FIRST(r->r_sharehead);
572 		if (r->r_flags & RF_FIRSTSHARE) {
573 			s->r_flags |= RF_FIRSTSHARE;
574 			TAILQ_INSERT_BEFORE(r, s, r_link);
575 			TAILQ_REMOVE(&rm->rm_list, r, r_link);
576 		}
577 
578 		/*
579 		 * Make sure that the sharing list goes away completely
580 		 * if the resource is no longer being shared at all.
581 		 */
582 		if (LIST_NEXT(s, r_sharelink) == NULL) {
583 			free(s->r_sharehead, M_RMAN);
584 			s->r_sharehead = NULL;
585 			s->r_flags &= ~RF_FIRSTSHARE;
586 		}
587 		goto out;
588 	}
589 
590 	/*
591 	 * Look at the adjacent resources in the list and see if our
592 	 * segment can be merged with any of them.  If either of the
593 	 * resources is allocated or is not exactly adjacent then they
594 	 * cannot be merged with our segment.
595 	 */
596 	s = TAILQ_PREV(r, resource_head, r_link);
597 	if (s != NULL && ((s->r_flags & RF_ALLOCATED) != 0 ||
598 	    s->r_end + 1 != r->r_start))
599 		s = NULL;
600 	t = TAILQ_NEXT(r, r_link);
601 	if (t != NULL && ((t->r_flags & RF_ALLOCATED) != 0 ||
602 	    r->r_end + 1 != t->r_start))
603 		t = NULL;
604 
605 	if (s != NULL && t != NULL) {
606 		/*
607 		 * Merge all three segments.
608 		 */
609 		s->r_end = t->r_end;
610 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
611 		TAILQ_REMOVE(&rm->rm_list, t, r_link);
612 		free(t, M_RMAN);
613 	} else if (s != NULL) {
614 		/*
615 		 * Merge previous segment with ours.
616 		 */
617 		s->r_end = r->r_end;
618 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
619 	} else if (t != NULL) {
620 		/*
621 		 * Merge next segment with ours.
622 		 */
623 		t->r_start = r->r_start;
624 		TAILQ_REMOVE(&rm->rm_list, r, r_link);
625 	} else {
626 		/*
627 		 * At this point, we know there is nothing we
628 		 * can potentially merge with, because on each
629 		 * side, there is either nothing there or what is
630 		 * there is still allocated.  In that case, we don't
631 		 * want to remove r from the list; we simply want to
632 		 * change it to an unallocated region and return
633 		 * without freeing anything.
634 		 */
635 		r->r_flags &= ~RF_ALLOCATED;
636 		return 0;
637 	}
638 
639 out:
640 	free(r, M_RMAN);
641 	return 0;
642 }
643 
644 int
645 rman_release_resource(struct resource *re)
646 {
647 	int	rv;
648 	struct	resource_i *r;
649 	struct	rman *rm;
650 
651 	r = re->__r_i;
652 	rm = r->r_rm;
653 	mtx_lock(rm->rm_mtx);
654 	rv = int_rman_release_resource(rm, r);
655 	mtx_unlock(rm->rm_mtx);
656 	return (rv);
657 }
658 
659 uint32_t
660 rman_make_alignment_flags(uint32_t size)
661 {
662 	int	i;
663 
664 	/*
665 	 * Find the hightest bit set, and add one if more than one bit
666 	 * set.  We're effectively computing the ceil(log2(size)) here.
667 	 */
668 	for (i = 31; i > 0; i--)
669 		if ((1 << i) & size)
670 			break;
671 	if (~(1 << i) & size)
672 		i++;
673 
674 	return(RF_ALIGNMENT_LOG2(i));
675 }
676 
677 u_long
678 rman_get_start(struct resource *r)
679 {
680 	return (r->__r_i->r_start);
681 }
682 
683 u_long
684 rman_get_end(struct resource *r)
685 {
686 	return (r->__r_i->r_end);
687 }
688 
689 u_long
690 rman_get_size(struct resource *r)
691 {
692 	return (r->__r_i->r_end - r->__r_i->r_start + 1);
693 }
694 
695 u_int
696 rman_get_flags(struct resource *r)
697 {
698 	return (r->__r_i->r_flags);
699 }
700 
701 void
702 rman_set_virtual(struct resource *r, void *v)
703 {
704 	r->__r_i->r_virtual = v;
705 }
706 
707 void *
708 rman_get_virtual(struct resource *r)
709 {
710 	return (r->__r_i->r_virtual);
711 }
712 
713 void
714 rman_set_bustag(struct resource *r, bus_space_tag_t t)
715 {
716 	r->r_bustag = t;
717 }
718 
719 bus_space_tag_t
720 rman_get_bustag(struct resource *r)
721 {
722 	return (r->r_bustag);
723 }
724 
725 void
726 rman_set_bushandle(struct resource *r, bus_space_handle_t h)
727 {
728 	r->r_bushandle = h;
729 }
730 
731 bus_space_handle_t
732 rman_get_bushandle(struct resource *r)
733 {
734 	return (r->r_bushandle);
735 }
736 
737 void
738 rman_set_rid(struct resource *r, int rid)
739 {
740 	r->__r_i->r_rid = rid;
741 }
742 
743 void
744 rman_set_start(struct resource *r, u_long start)
745 {
746 	r->__r_i->r_start = start;
747 }
748 
749 void
750 rman_set_end(struct resource *r, u_long end)
751 {
752 	r->__r_i->r_end = end;
753 }
754 
755 int
756 rman_get_rid(struct resource *r)
757 {
758 	return (r->__r_i->r_rid);
759 }
760 
761 struct device *
762 rman_get_device(struct resource *r)
763 {
764 	return (r->__r_i->r_dev);
765 }
766 
767 void
768 rman_set_device(struct resource *r, struct device *dev)
769 {
770 	r->__r_i->r_dev = dev;
771 }
772 
773 int
774 rman_is_region_manager(struct resource *r, struct rman *rm)
775 {
776 
777 	return (r->__r_i->r_rm == rm);
778 }
779 
780 /*
781  * Sysctl interface for scanning the resource lists.
782  *
783  * We take two input parameters; the index into the list of resource
784  * managers, and the resource offset into the list.
785  */
786 static int
787 sysctl_rman(SYSCTL_HANDLER_ARGS)
788 {
789 	int			*name = (int *)arg1;
790 	u_int			namelen = arg2;
791 	int			rman_idx, res_idx;
792 	struct rman		*rm;
793 	struct resource_i	*res;
794 	struct u_rman		urm;
795 	struct u_resource	ures;
796 	int			error;
797 
798 	if (namelen != 3)
799 		return (EINVAL);
800 
801 	if (bus_data_generation_check(name[0]))
802 		return (EINVAL);
803 	rman_idx = name[1];
804 	res_idx = name[2];
805 
806 	/*
807 	 * Find the indexed resource manager
808 	 */
809 	mtx_lock(&rman_mtx);
810 	TAILQ_FOREACH(rm, &rman_head, rm_link) {
811 		if (rman_idx-- == 0)
812 			break;
813 	}
814 	mtx_unlock(&rman_mtx);
815 	if (rm == NULL)
816 		return (ENOENT);
817 
818 	/*
819 	 * If the resource index is -1, we want details on the
820 	 * resource manager.
821 	 */
822 	if (res_idx == -1) {
823 		bzero(&urm, sizeof(urm));
824 		urm.rm_handle = (uintptr_t)rm;
825 		strlcpy(urm.rm_descr, rm->rm_descr, RM_TEXTLEN);
826 		urm.rm_start = rm->rm_start;
827 		urm.rm_size = rm->rm_end - rm->rm_start + 1;
828 		urm.rm_type = rm->rm_type;
829 
830 		error = SYSCTL_OUT(req, &urm, sizeof(urm));
831 		return (error);
832 	}
833 
834 	/*
835 	 * Find the indexed resource and return it.
836 	 */
837 	mtx_lock(rm->rm_mtx);
838 	TAILQ_FOREACH(res, &rm->rm_list, r_link) {
839 		if (res_idx-- == 0) {
840 			bzero(&ures, sizeof(ures));
841 			ures.r_handle = (uintptr_t)res;
842 			ures.r_parent = (uintptr_t)res->r_rm;
843 			ures.r_device = (uintptr_t)res->r_dev;
844 			if (res->r_dev != NULL) {
845 				if (device_get_name(res->r_dev) != NULL) {
846 					snprintf(ures.r_devname, RM_TEXTLEN,
847 					    "%s%d",
848 					    device_get_name(res->r_dev),
849 					    device_get_unit(res->r_dev));
850 				} else {
851 					strlcpy(ures.r_devname, "nomatch",
852 					    RM_TEXTLEN);
853 				}
854 			} else {
855 				ures.r_devname[0] = '\0';
856 			}
857 			ures.r_start = res->r_start;
858 			ures.r_size = res->r_end - res->r_start + 1;
859 			ures.r_flags = res->r_flags;
860 
861 			mtx_unlock(rm->rm_mtx);
862 			error = SYSCTL_OUT(req, &ures, sizeof(ures));
863 			return (error);
864 		}
865 	}
866 	mtx_unlock(rm->rm_mtx);
867 	return (ENOENT);
868 }
869 
870 SYSCTL_NODE(_hw_bus, OID_AUTO, rman, CTLFLAG_RD, sysctl_rman,
871     "kernel resource manager");
872