The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_rman.c

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    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: releng/8.2/sys/kern/subr_rman.c 199583 2009-11-20 15:27:52Z jhb $");
   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_type == RMAN_UNINIT)
  142                 panic("rman_init");
  143         if (rm->rm_type == RMAN_GAUGE)
  144                 panic("implement RMAN_GAUGE");
  145 
  146         TAILQ_INIT(&rm->rm_list);
  147         rm->rm_mtx = malloc(sizeof *rm->rm_mtx, M_RMAN, M_NOWAIT | M_ZERO);
  148         if (rm->rm_mtx == NULL)
  149                 return ENOMEM;
  150         mtx_init(rm->rm_mtx, "rman", NULL, MTX_DEF);
  151 
  152         mtx_lock(&rman_mtx);
  153         TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
  154         mtx_unlock(&rman_mtx);
  155         return 0;
  156 }
  157 
  158 int
  159 rman_manage_region(struct rman *rm, u_long start, u_long end)
  160 {
  161         struct resource_i *r, *s, *t;
  162 
  163         DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
  164             rm->rm_descr, start, end));
  165         r = int_alloc_resource(M_NOWAIT);
  166         if (r == NULL)
  167                 return ENOMEM;
  168         r->r_start = start;
  169         r->r_end = end;
  170         r->r_rm = rm;
  171 
  172         mtx_lock(rm->rm_mtx);
  173 
  174         /* Skip entries before us. */
  175         TAILQ_FOREACH(s, &rm->rm_list, r_link) {
  176                 if (s->r_end == ULONG_MAX)
  177                         break;
  178                 if (s->r_end + 1 >= r->r_start)
  179                         break;
  180         }
  181 
  182         /* If we ran off the end of the list, insert at the tail. */
  183         if (s == NULL) {
  184                 TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link);
  185         } else {
  186                 /* Check for any overlap with the current region. */
  187                 if (r->r_start <= s->r_end && r->r_end >= s->r_start)
  188                         return EBUSY;
  189 
  190                 /* Check for any overlap with the next region. */
  191                 t = TAILQ_NEXT(s, r_link);
  192                 if (t && r->r_start <= t->r_end && r->r_end >= t->r_start)
  193                         return EBUSY;
  194 
  195                 /*
  196                  * See if this region can be merged with the next region.  If
  197                  * not, clear the pointer.
  198                  */
  199                 if (t && (r->r_end + 1 != t->r_start || t->r_flags != 0))
  200                         t = NULL;
  201 
  202                 /* See if we can merge with the current region. */
  203                 if (s->r_end + 1 == r->r_start && s->r_flags == 0) {
  204                         /* Can we merge all 3 regions? */
  205                         if (t != NULL) {
  206                                 s->r_end = t->r_end;
  207                                 TAILQ_REMOVE(&rm->rm_list, t, r_link);
  208                                 free(r, M_RMAN);
  209                                 free(t, M_RMAN);
  210                         } else {
  211                                 s->r_end = r->r_end;
  212                                 free(r, M_RMAN);
  213                         }
  214                 } else if (t != NULL) {
  215                         /* Can we merge with just the next region? */
  216                         t->r_start = r->r_start;
  217                         free(r, M_RMAN);
  218                 } else if (s->r_end < r->r_start) {
  219                         TAILQ_INSERT_AFTER(&rm->rm_list, s, r, r_link);
  220                 } else {
  221                         TAILQ_INSERT_BEFORE(s, r, r_link);
  222                 }
  223         }
  224 
  225         mtx_unlock(rm->rm_mtx);
  226         return 0;
  227 }
  228 
  229 int
  230 rman_init_from_resource(struct rman *rm, struct resource *r)
  231 {
  232         int rv;
  233 
  234         if ((rv = rman_init(rm)) != 0)
  235                 return (rv);
  236         return (rman_manage_region(rm, r->__r_i->r_start, r->__r_i->r_end));
  237 }
  238 
  239 int
  240 rman_fini(struct rman *rm)
  241 {
  242         struct resource_i *r;
  243 
  244         mtx_lock(rm->rm_mtx);
  245         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
  246                 if (r->r_flags & RF_ALLOCATED) {
  247                         mtx_unlock(rm->rm_mtx);
  248                         return EBUSY;
  249                 }
  250         }
  251 
  252         /*
  253          * There really should only be one of these if we are in this
  254          * state and the code is working properly, but it can't hurt.
  255          */
  256         while (!TAILQ_EMPTY(&rm->rm_list)) {
  257                 r = TAILQ_FIRST(&rm->rm_list);
  258                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  259                 free(r, M_RMAN);
  260         }
  261         mtx_unlock(rm->rm_mtx);
  262         mtx_lock(&rman_mtx);
  263         TAILQ_REMOVE(&rman_head, rm, rm_link);
  264         mtx_unlock(&rman_mtx);
  265         mtx_destroy(rm->rm_mtx);
  266         free(rm->rm_mtx, M_RMAN);
  267 
  268         return 0;
  269 }
  270 
  271 struct resource *
  272 rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
  273                       u_long count, u_long bound,  u_int flags,
  274                       struct device *dev)
  275 {
  276         u_int   want_activate;
  277         struct  resource_i *r, *s, *rv;
  278         u_long  rstart, rend, amask, bmask;
  279 
  280         rv = NULL;
  281 
  282         DPRINTF(("rman_reserve_resource_bound: <%s> request: [%#lx, %#lx], "
  283                "length %#lx, flags %u, device %s\n", rm->rm_descr, start, end,
  284                count, flags,
  285                dev == NULL ? "<null>" : device_get_nameunit(dev)));
  286         want_activate = (flags & RF_ACTIVE);
  287         flags &= ~RF_ACTIVE;
  288 
  289         mtx_lock(rm->rm_mtx);
  290 
  291         for (r = TAILQ_FIRST(&rm->rm_list);
  292              r && r->r_end < start;
  293              r = TAILQ_NEXT(r, r_link))
  294                 ;
  295 
  296         if (r == NULL) {
  297                 DPRINTF(("could not find a region\n"));
  298                 goto out;
  299         }
  300 
  301         amask = (1ul << RF_ALIGNMENT(flags)) - 1;
  302         /* If bound is 0, bmask will also be 0 */
  303         bmask = ~(bound - 1);
  304         /*
  305          * First try to find an acceptable totally-unshared region.
  306          */
  307         for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
  308                 DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end));
  309                 if (s->r_start + count - 1 > end) {
  310                         DPRINTF(("s->r_start (%#lx) + count - 1> end (%#lx)\n",
  311                             s->r_start, end));
  312                         break;
  313                 }
  314                 if (s->r_flags & RF_ALLOCATED) {
  315                         DPRINTF(("region is allocated\n"));
  316                         continue;
  317                 }
  318                 rstart = ulmax(s->r_start, start);
  319                 /*
  320                  * Try to find a region by adjusting to boundary and alignment
  321                  * until both conditions are satisfied. This is not an optimal
  322                  * algorithm, but in most cases it isn't really bad, either.
  323                  */
  324                 do {
  325                         rstart = (rstart + amask) & ~amask;
  326                         if (((rstart ^ (rstart + count - 1)) & bmask) != 0)
  327                                 rstart += bound - (rstart & ~bmask);
  328                 } while ((rstart & amask) != 0 && rstart < end &&
  329                     rstart < s->r_end);
  330                 rend = ulmin(s->r_end, ulmax(rstart + count - 1, end));
  331                 if (rstart > rend) {
  332                         DPRINTF(("adjusted start exceeds end\n"));
  333                         continue;
  334                 }
  335                 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
  336                        rstart, rend, (rend - rstart + 1), count));
  337 
  338                 if ((rend - rstart + 1) >= count) {
  339                         DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n",
  340                                rstart, rend, (rend - rstart + 1)));
  341                         if ((s->r_end - s->r_start + 1) == count) {
  342                                 DPRINTF(("candidate region is entire chunk\n"));
  343                                 rv = s;
  344                                 rv->r_flags |= RF_ALLOCATED | flags;
  345                                 rv->r_dev = dev;
  346                                 goto out;
  347                         }
  348 
  349                         /*
  350                          * If s->r_start < rstart and
  351                          *    s->r_end > rstart + count - 1, then
  352                          * we need to split the region into three pieces
  353                          * (the middle one will get returned to the user).
  354                          * Otherwise, we are allocating at either the
  355                          * beginning or the end of s, so we only need to
  356                          * split it in two.  The first case requires
  357                          * two new allocations; the second requires but one.
  358                          */
  359                         rv = int_alloc_resource(M_NOWAIT);
  360                         if (rv == NULL)
  361                                 goto out;
  362                         rv->r_start = rstart;
  363                         rv->r_end = rstart + count - 1;
  364                         rv->r_flags = flags | RF_ALLOCATED;
  365                         rv->r_dev = dev;
  366                         rv->r_rm = rm;
  367 
  368                         if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
  369                                 DPRINTF(("splitting region in three parts: "
  370                                        "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n",
  371                                        s->r_start, rv->r_start - 1,
  372                                        rv->r_start, rv->r_end,
  373                                        rv->r_end + 1, s->r_end));
  374                                 /*
  375                                  * We are allocating in the middle.
  376                                  */
  377                                 r = int_alloc_resource(M_NOWAIT);
  378                                 if (r == NULL) {
  379                                         free(rv, M_RMAN);
  380                                         rv = NULL;
  381                                         goto out;
  382                                 }
  383                                 r->r_start = rv->r_end + 1;
  384                                 r->r_end = s->r_end;
  385                                 r->r_flags = s->r_flags;
  386                                 r->r_rm = rm;
  387                                 s->r_end = rv->r_start - 1;
  388                                 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
  389                                                      r_link);
  390                                 TAILQ_INSERT_AFTER(&rm->rm_list, rv, r,
  391                                                      r_link);
  392                         } else if (s->r_start == rv->r_start) {
  393                                 DPRINTF(("allocating from the beginning\n"));
  394                                 /*
  395                                  * We are allocating at the beginning.
  396                                  */
  397                                 s->r_start = rv->r_end + 1;
  398                                 TAILQ_INSERT_BEFORE(s, rv, r_link);
  399                         } else {
  400                                 DPRINTF(("allocating at the end\n"));
  401                                 /*
  402                                  * We are allocating at the end.
  403                                  */
  404                                 s->r_end = rv->r_start - 1;
  405                                 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
  406                                                      r_link);
  407                         }
  408                         goto out;
  409                 }
  410         }
  411 
  412         /*
  413          * Now find an acceptable shared region, if the client's requirements
  414          * allow sharing.  By our implementation restriction, a candidate
  415          * region must match exactly by both size and sharing type in order
  416          * to be considered compatible with the client's request.  (The
  417          * former restriction could probably be lifted without too much
  418          * additional work, but this does not seem warranted.)
  419          */
  420         DPRINTF(("no unshared regions found\n"));
  421         if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
  422                 goto out;
  423 
  424         for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
  425                 if (s->r_start > end)
  426                         break;
  427                 if ((s->r_flags & flags) != flags)
  428                         continue;
  429                 rstart = ulmax(s->r_start, start);
  430                 rend = ulmin(s->r_end, ulmax(start + count - 1, end));
  431                 if (s->r_start >= start && s->r_end <= end
  432                     && (s->r_end - s->r_start + 1) == count &&
  433                     (s->r_start & amask) == 0 &&
  434                     ((s->r_start ^ s->r_end) & bmask) == 0) {
  435                         rv = int_alloc_resource(M_NOWAIT);
  436                         if (rv == NULL)
  437                                 goto out;
  438                         rv->r_start = s->r_start;
  439                         rv->r_end = s->r_end;
  440                         rv->r_flags = s->r_flags &
  441                                 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
  442                         rv->r_dev = dev;
  443                         rv->r_rm = rm;
  444                         if (s->r_sharehead == NULL) {
  445                                 s->r_sharehead = malloc(sizeof *s->r_sharehead,
  446                                                 M_RMAN, M_NOWAIT | M_ZERO);
  447                                 if (s->r_sharehead == NULL) {
  448                                         free(rv, M_RMAN);
  449                                         rv = NULL;
  450                                         goto out;
  451                                 }
  452                                 LIST_INIT(s->r_sharehead);
  453                                 LIST_INSERT_HEAD(s->r_sharehead, s,
  454                                                  r_sharelink);
  455                                 s->r_flags |= RF_FIRSTSHARE;
  456                         }
  457                         rv->r_sharehead = s->r_sharehead;
  458                         LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
  459                         goto out;
  460                 }
  461         }
  462 
  463         /*
  464          * We couldn't find anything.
  465          */
  466 out:
  467         /*
  468          * If the user specified RF_ACTIVE in the initial flags,
  469          * which is reflected in `want_activate', we attempt to atomically
  470          * activate the resource.  If this fails, we release the resource
  471          * and indicate overall failure.  (This behavior probably doesn't
  472          * make sense for RF_TIMESHARE-type resources.)
  473          */
  474         if (rv && want_activate) {
  475                 struct resource_i *whohas;
  476                 if (int_rman_activate_resource(rm, rv, &whohas)) {
  477                         int_rman_release_resource(rm, rv);
  478                         rv = NULL;
  479                 }
  480         }
  481 
  482         mtx_unlock(rm->rm_mtx);
  483         return (rv == NULL ? NULL : &rv->r_r);
  484 }
  485 
  486 struct resource *
  487 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
  488                       u_int flags, struct device *dev)
  489 {
  490 
  491         return (rman_reserve_resource_bound(rm, start, end, count, 0, flags,
  492             dev));
  493 }
  494 
  495 static int
  496 int_rman_activate_resource(struct rman *rm, struct resource_i *r,
  497                            struct resource_i **whohas)
  498 {
  499         struct resource_i *s;
  500         int ok;
  501 
  502         /*
  503          * If we are not timesharing, then there is nothing much to do.
  504          * If we already have the resource, then there is nothing at all to do.
  505          * If we are not on a sharing list with anybody else, then there is
  506          * little to do.
  507          */
  508         if ((r->r_flags & RF_TIMESHARE) == 0
  509             || (r->r_flags & RF_ACTIVE) != 0
  510             || r->r_sharehead == NULL) {
  511                 r->r_flags |= RF_ACTIVE;
  512                 return 0;
  513         }
  514 
  515         ok = 1;
  516         for (s = LIST_FIRST(r->r_sharehead); s && ok;
  517              s = LIST_NEXT(s, r_sharelink)) {
  518                 if ((s->r_flags & RF_ACTIVE) != 0) {
  519                         ok = 0;
  520                         *whohas = s;
  521                 }
  522         }
  523         if (ok) {
  524                 r->r_flags |= RF_ACTIVE;
  525                 return 0;
  526         }
  527         return EBUSY;
  528 }
  529 
  530 int
  531 rman_activate_resource(struct resource *re)
  532 {
  533         int rv;
  534         struct resource_i *r, *whohas;
  535         struct rman *rm;
  536 
  537         r = re->__r_i;
  538         rm = r->r_rm;
  539         mtx_lock(rm->rm_mtx);
  540         rv = int_rman_activate_resource(rm, r, &whohas);
  541         mtx_unlock(rm->rm_mtx);
  542         return rv;
  543 }
  544 
  545 int
  546 rman_await_resource(struct resource *re, int pri, int timo)
  547 {
  548         int     rv;
  549         struct  resource_i *r, *whohas;
  550         struct  rman *rm;
  551 
  552         r = re->__r_i;
  553         rm = r->r_rm;
  554         mtx_lock(rm->rm_mtx);
  555         for (;;) {
  556                 rv = int_rman_activate_resource(rm, r, &whohas);
  557                 if (rv != EBUSY)
  558                         return (rv);    /* returns with mutex held */
  559 
  560                 if (r->r_sharehead == NULL)
  561                         panic("rman_await_resource");
  562                 whohas->r_flags |= RF_WANTED;
  563                 rv = msleep(r->r_sharehead, rm->rm_mtx, pri, "rmwait", timo);
  564                 if (rv) {
  565                         mtx_unlock(rm->rm_mtx);
  566                         return (rv);
  567                 }
  568         }
  569 }
  570 
  571 static int
  572 int_rman_deactivate_resource(struct resource_i *r)
  573 {
  574 
  575         r->r_flags &= ~RF_ACTIVE;
  576         if (r->r_flags & RF_WANTED) {
  577                 r->r_flags &= ~RF_WANTED;
  578                 wakeup(r->r_sharehead);
  579         }
  580         return 0;
  581 }
  582 
  583 int
  584 rman_deactivate_resource(struct resource *r)
  585 {
  586         struct  rman *rm;
  587 
  588         rm = r->__r_i->r_rm;
  589         mtx_lock(rm->rm_mtx);
  590         int_rman_deactivate_resource(r->__r_i);
  591         mtx_unlock(rm->rm_mtx);
  592         return 0;
  593 }
  594 
  595 static int
  596 int_rman_release_resource(struct rman *rm, struct resource_i *r)
  597 {
  598         struct  resource_i *s, *t;
  599 
  600         if (r->r_flags & RF_ACTIVE)
  601                 int_rman_deactivate_resource(r);
  602 
  603         /*
  604          * Check for a sharing list first.  If there is one, then we don't
  605          * have to think as hard.
  606          */
  607         if (r->r_sharehead) {
  608                 /*
  609                  * If a sharing list exists, then we know there are at
  610                  * least two sharers.
  611                  *
  612                  * If we are in the main circleq, appoint someone else.
  613                  */
  614                 LIST_REMOVE(r, r_sharelink);
  615                 s = LIST_FIRST(r->r_sharehead);
  616                 if (r->r_flags & RF_FIRSTSHARE) {
  617                         s->r_flags |= RF_FIRSTSHARE;
  618                         TAILQ_INSERT_BEFORE(r, s, r_link);
  619                         TAILQ_REMOVE(&rm->rm_list, r, r_link);
  620                 }
  621 
  622                 /*
  623                  * Make sure that the sharing list goes away completely
  624                  * if the resource is no longer being shared at all.
  625                  */
  626                 if (LIST_NEXT(s, r_sharelink) == NULL) {
  627                         free(s->r_sharehead, M_RMAN);
  628                         s->r_sharehead = NULL;
  629                         s->r_flags &= ~RF_FIRSTSHARE;
  630                 }
  631                 goto out;
  632         }
  633 
  634         /*
  635          * Look at the adjacent resources in the list and see if our
  636          * segment can be merged with any of them.  If either of the
  637          * resources is allocated or is not exactly adjacent then they
  638          * cannot be merged with our segment.
  639          */
  640         s = TAILQ_PREV(r, resource_head, r_link);
  641         if (s != NULL && ((s->r_flags & RF_ALLOCATED) != 0 ||
  642             s->r_end + 1 != r->r_start))
  643                 s = NULL;
  644         t = TAILQ_NEXT(r, r_link);
  645         if (t != NULL && ((t->r_flags & RF_ALLOCATED) != 0 ||
  646             r->r_end + 1 != t->r_start))
  647                 t = NULL;
  648 
  649         if (s != NULL && t != NULL) {
  650                 /*
  651                  * Merge all three segments.
  652                  */
  653                 s->r_end = t->r_end;
  654                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  655                 TAILQ_REMOVE(&rm->rm_list, t, r_link);
  656                 free(t, M_RMAN);
  657         } else if (s != NULL) {
  658                 /*
  659                  * Merge previous segment with ours.
  660                  */
  661                 s->r_end = r->r_end;
  662                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  663         } else if (t != NULL) {
  664                 /*
  665                  * Merge next segment with ours.
  666                  */
  667                 t->r_start = r->r_start;
  668                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  669         } else {
  670                 /*
  671                  * At this point, we know there is nothing we
  672                  * can potentially merge with, because on each
  673                  * side, there is either nothing there or what is
  674                  * there is still allocated.  In that case, we don't
  675                  * want to remove r from the list; we simply want to
  676                  * change it to an unallocated region and return
  677                  * without freeing anything.
  678                  */
  679                 r->r_flags &= ~RF_ALLOCATED;
  680                 return 0;
  681         }
  682 
  683 out:
  684         free(r, M_RMAN);
  685         return 0;
  686 }
  687 
  688 int
  689 rman_release_resource(struct resource *re)
  690 {
  691         int     rv;
  692         struct  resource_i *r;
  693         struct  rman *rm;
  694 
  695         r = re->__r_i;
  696         rm = r->r_rm;
  697         mtx_lock(rm->rm_mtx);
  698         rv = int_rman_release_resource(rm, r);
  699         mtx_unlock(rm->rm_mtx);
  700         return (rv);
  701 }
  702 
  703 uint32_t
  704 rman_make_alignment_flags(uint32_t size)
  705 {
  706         int     i;
  707 
  708         /*
  709          * Find the hightest bit set, and add one if more than one bit
  710          * set.  We're effectively computing the ceil(log2(size)) here.
  711          */
  712         for (i = 31; i > 0; i--)
  713                 if ((1 << i) & size)
  714                         break;
  715         if (~(1 << i) & size)
  716                 i++;
  717 
  718         return(RF_ALIGNMENT_LOG2(i));
  719 }
  720 
  721 void
  722 rman_set_start(struct resource *r, u_long start)
  723 {
  724         r->__r_i->r_start = start;
  725 }
  726 
  727 u_long
  728 rman_get_start(struct resource *r)
  729 {
  730         return (r->__r_i->r_start);
  731 }
  732 
  733 void
  734 rman_set_end(struct resource *r, u_long end)
  735 {
  736         r->__r_i->r_end = end;
  737 }
  738 
  739 u_long
  740 rman_get_end(struct resource *r)
  741 {
  742         return (r->__r_i->r_end);
  743 }
  744 
  745 u_long
  746 rman_get_size(struct resource *r)
  747 {
  748         return (r->__r_i->r_end - r->__r_i->r_start + 1);
  749 }
  750 
  751 u_int
  752 rman_get_flags(struct resource *r)
  753 {
  754         return (r->__r_i->r_flags);
  755 }
  756 
  757 void
  758 rman_set_virtual(struct resource *r, void *v)
  759 {
  760         r->__r_i->r_virtual = v;
  761 }
  762 
  763 void *
  764 rman_get_virtual(struct resource *r)
  765 {
  766         return (r->__r_i->r_virtual);
  767 }
  768 
  769 void
  770 rman_set_bustag(struct resource *r, bus_space_tag_t t)
  771 {
  772         r->r_bustag = t;
  773 }
  774 
  775 bus_space_tag_t
  776 rman_get_bustag(struct resource *r)
  777 {
  778         return (r->r_bustag);
  779 }
  780 
  781 void
  782 rman_set_bushandle(struct resource *r, bus_space_handle_t h)
  783 {
  784         r->r_bushandle = h;
  785 }
  786 
  787 bus_space_handle_t
  788 rman_get_bushandle(struct resource *r)
  789 {
  790         return (r->r_bushandle);
  791 }
  792 
  793 void
  794 rman_set_rid(struct resource *r, int rid)
  795 {
  796         r->__r_i->r_rid = rid;
  797 }
  798 
  799 int
  800 rman_get_rid(struct resource *r)
  801 {
  802         return (r->__r_i->r_rid);
  803 }
  804 
  805 void
  806 rman_set_device(struct resource *r, struct device *dev)
  807 {
  808         r->__r_i->r_dev = dev;
  809 }
  810 
  811 struct device *
  812 rman_get_device(struct resource *r)
  813 {
  814         return (r->__r_i->r_dev);
  815 }
  816 
  817 int
  818 rman_is_region_manager(struct resource *r, struct rman *rm)
  819 {
  820 
  821         return (r->__r_i->r_rm == rm);
  822 }
  823 
  824 /*
  825  * Sysctl interface for scanning the resource lists.
  826  *
  827  * We take two input parameters; the index into the list of resource
  828  * managers, and the resource offset into the list.
  829  */
  830 static int
  831 sysctl_rman(SYSCTL_HANDLER_ARGS)
  832 {
  833         int                     *name = (int *)arg1;
  834         u_int                   namelen = arg2;
  835         int                     rman_idx, res_idx;
  836         struct rman             *rm;
  837         struct resource_i       *res;
  838         struct resource_i       *sres;
  839         struct u_rman           urm;
  840         struct u_resource       ures;
  841         int                     error;
  842 
  843         if (namelen != 3)
  844                 return (EINVAL);
  845 
  846         if (bus_data_generation_check(name[0]))
  847                 return (EINVAL);
  848         rman_idx = name[1];
  849         res_idx = name[2];
  850 
  851         /*
  852          * Find the indexed resource manager
  853          */
  854         mtx_lock(&rman_mtx);
  855         TAILQ_FOREACH(rm, &rman_head, rm_link) {
  856                 if (rman_idx-- == 0)
  857                         break;
  858         }
  859         mtx_unlock(&rman_mtx);
  860         if (rm == NULL)
  861                 return (ENOENT);
  862 
  863         /*
  864          * If the resource index is -1, we want details on the
  865          * resource manager.
  866          */
  867         if (res_idx == -1) {
  868                 bzero(&urm, sizeof(urm));
  869                 urm.rm_handle = (uintptr_t)rm;
  870                 if (rm->rm_descr != NULL)
  871                         strlcpy(urm.rm_descr, rm->rm_descr, RM_TEXTLEN);
  872                 urm.rm_start = rm->rm_start;
  873                 urm.rm_size = rm->rm_end - rm->rm_start + 1;
  874                 urm.rm_type = rm->rm_type;
  875 
  876                 error = SYSCTL_OUT(req, &urm, sizeof(urm));
  877                 return (error);
  878         }
  879 
  880         /*
  881          * Find the indexed resource and return it.
  882          */
  883         mtx_lock(rm->rm_mtx);
  884         TAILQ_FOREACH(res, &rm->rm_list, r_link) {
  885                 if (res->r_sharehead != NULL) {
  886                         LIST_FOREACH(sres, res->r_sharehead, r_sharelink)
  887                                 if (res_idx-- == 0) {
  888                                         res = sres;
  889                                         goto found;
  890                                 }
  891                 }
  892                 else if (res_idx-- == 0)
  893                                 goto found;
  894         }
  895         mtx_unlock(rm->rm_mtx);
  896         return (ENOENT);
  897 
  898 found:
  899         bzero(&ures, sizeof(ures));
  900         ures.r_handle = (uintptr_t)res;
  901         ures.r_parent = (uintptr_t)res->r_rm;
  902         ures.r_device = (uintptr_t)res->r_dev;
  903         if (res->r_dev != NULL) {
  904                 if (device_get_name(res->r_dev) != NULL) {
  905                         snprintf(ures.r_devname, RM_TEXTLEN,
  906                             "%s%d",
  907                             device_get_name(res->r_dev),
  908                             device_get_unit(res->r_dev));
  909                 } else {
  910                         strlcpy(ures.r_devname, "nomatch",
  911                             RM_TEXTLEN);
  912                 }
  913         } else {
  914                 ures.r_devname[0] = '\0';
  915         }
  916         ures.r_start = res->r_start;
  917         ures.r_size = res->r_end - res->r_start + 1;
  918         ures.r_flags = res->r_flags;
  919 
  920         mtx_unlock(rm->rm_mtx);
  921         error = SYSCTL_OUT(req, &ures, sizeof(ures));
  922         return (error);
  923 }
  924 
  925 SYSCTL_NODE(_hw_bus, OID_AUTO, rman, CTLFLAG_RD, sysctl_rman,
  926     "kernel resource manager");
  927 
  928 #ifdef DDB
  929 static void
  930 dump_rman(struct rman *rm)
  931 {
  932         struct resource_i *r;
  933         const char *devname;
  934 
  935         if (db_pager_quit)
  936                 return;
  937         db_printf("rman: %s\n", rm->rm_descr);
  938         db_printf("    0x%lx-0x%lx (full range)\n", rm->rm_start, rm->rm_end);
  939         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
  940                 if (r->r_dev != NULL) {
  941                         devname = device_get_nameunit(r->r_dev);
  942                         if (devname == NULL)
  943                                 devname = "nomatch";
  944                 } else
  945                         devname = NULL;
  946                 db_printf("    0x%lx-0x%lx ", r->r_start, r->r_end);
  947                 if (devname != NULL)
  948                         db_printf("(%s)\n", devname);
  949                 else
  950                         db_printf("----\n");
  951                 if (db_pager_quit)
  952                         return;
  953         }
  954 }
  955 
  956 DB_SHOW_COMMAND(rman, db_show_rman)
  957 {
  958 
  959         if (have_addr)
  960                 dump_rman((struct rman *)addr);
  961 }
  962 
  963 DB_SHOW_ALL_COMMAND(rman, db_show_all_rman)
  964 {
  965         struct rman *rm;
  966 
  967         TAILQ_FOREACH(rm, &rman_head, rm_link)
  968                 dump_rman(rm);
  969 }
  970 DB_SHOW_ALIAS(allrman, db_show_all_rman);
  971 #endif

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