The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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/8.3/sys/kern/subr_rman.c 223501 2011-06-24 13:45:14Z 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_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 
  165         DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n",
  166             rm->rm_descr, start, end));
  167         if (start < rm->rm_start || end > rm->rm_end)
  168                 return EINVAL;
  169         r = int_alloc_resource(M_NOWAIT);
  170         if (r == NULL)
  171                 return ENOMEM;
  172         r->r_start = start;
  173         r->r_end = end;
  174         r->r_rm = rm;
  175 
  176         mtx_lock(rm->rm_mtx);
  177 
  178         /* Skip entries before us. */
  179         TAILQ_FOREACH(s, &rm->rm_list, r_link) {
  180                 if (s->r_end == ULONG_MAX)
  181                         break;
  182                 if (s->r_end + 1 >= r->r_start)
  183                         break;
  184         }
  185 
  186         /* If we ran off the end of the list, insert at the tail. */
  187         if (s == NULL) {
  188                 TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link);
  189         } else {
  190                 /* Check for any overlap with the current region. */
  191                 if (r->r_start <= s->r_end && r->r_end >= s->r_start)
  192                         return EBUSY;
  193 
  194                 /* Check for any overlap with the next region. */
  195                 t = TAILQ_NEXT(s, r_link);
  196                 if (t && r->r_start <= t->r_end && r->r_end >= t->r_start)
  197                         return EBUSY;
  198 
  199                 /*
  200                  * See if this region can be merged with the next region.  If
  201                  * not, clear the pointer.
  202                  */
  203                 if (t && (r->r_end + 1 != t->r_start || t->r_flags != 0))
  204                         t = NULL;
  205 
  206                 /* See if we can merge with the current region. */
  207                 if (s->r_end + 1 == r->r_start && s->r_flags == 0) {
  208                         /* Can we merge all 3 regions? */
  209                         if (t != NULL) {
  210                                 s->r_end = t->r_end;
  211                                 TAILQ_REMOVE(&rm->rm_list, t, r_link);
  212                                 free(r, M_RMAN);
  213                                 free(t, M_RMAN);
  214                         } else {
  215                                 s->r_end = r->r_end;
  216                                 free(r, M_RMAN);
  217                         }
  218                 } else if (t != NULL) {
  219                         /* Can we merge with just the next region? */
  220                         t->r_start = r->r_start;
  221                         free(r, M_RMAN);
  222                 } else if (s->r_end < r->r_start) {
  223                         TAILQ_INSERT_AFTER(&rm->rm_list, s, r, r_link);
  224                 } else {
  225                         TAILQ_INSERT_BEFORE(s, r, r_link);
  226                 }
  227         }
  228 
  229         mtx_unlock(rm->rm_mtx);
  230         return 0;
  231 }
  232 
  233 int
  234 rman_init_from_resource(struct rman *rm, struct resource *r)
  235 {
  236         int rv;
  237 
  238         if ((rv = rman_init(rm)) != 0)
  239                 return (rv);
  240         return (rman_manage_region(rm, r->__r_i->r_start, r->__r_i->r_end));
  241 }
  242 
  243 int
  244 rman_fini(struct rman *rm)
  245 {
  246         struct resource_i *r;
  247 
  248         mtx_lock(rm->rm_mtx);
  249         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
  250                 if (r->r_flags & RF_ALLOCATED) {
  251                         mtx_unlock(rm->rm_mtx);
  252                         return EBUSY;
  253                 }
  254         }
  255 
  256         /*
  257          * There really should only be one of these if we are in this
  258          * state and the code is working properly, but it can't hurt.
  259          */
  260         while (!TAILQ_EMPTY(&rm->rm_list)) {
  261                 r = TAILQ_FIRST(&rm->rm_list);
  262                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  263                 free(r, M_RMAN);
  264         }
  265         mtx_unlock(rm->rm_mtx);
  266         mtx_lock(&rman_mtx);
  267         TAILQ_REMOVE(&rman_head, rm, rm_link);
  268         mtx_unlock(&rman_mtx);
  269         mtx_destroy(rm->rm_mtx);
  270         free(rm->rm_mtx, M_RMAN);
  271 
  272         return 0;
  273 }
  274 
  275 int
  276 rman_first_free_region(struct rman *rm, u_long *start, u_long *end)
  277 {
  278         struct resource_i *r;
  279 
  280         mtx_lock(rm->rm_mtx);
  281         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
  282                 if (!(r->r_flags & RF_ALLOCATED)) {
  283                         *start = r->r_start;
  284                         *end = r->r_end;
  285                         mtx_unlock(rm->rm_mtx);
  286                         return (0);
  287                 }
  288         }
  289         mtx_unlock(rm->rm_mtx);
  290         return (ENOENT);
  291 }
  292 
  293 int
  294 rman_last_free_region(struct rman *rm, u_long *start, u_long *end)
  295 {
  296         struct resource_i *r;
  297 
  298         mtx_lock(rm->rm_mtx);
  299         TAILQ_FOREACH_REVERSE(r, &rm->rm_list, resource_head, r_link) {
  300                 if (!(r->r_flags & RF_ALLOCATED)) {
  301                         *start = r->r_start;
  302                         *end = r->r_end;
  303                         mtx_unlock(rm->rm_mtx);
  304                         return (0);
  305                 }
  306         }
  307         mtx_unlock(rm->rm_mtx);
  308         return (ENOENT);
  309 }
  310 
  311 /* Shrink or extend one or both ends of an allocated resource. */
  312 int
  313 rman_adjust_resource(struct resource *rr, u_long start, u_long end)
  314 {
  315         struct  resource_i *r, *s, *t, *new;
  316         struct  rman *rm;
  317 
  318         /* Not supported for shared resources. */
  319         r = rr->__r_i;
  320         if (r->r_flags & (RF_TIMESHARE | RF_SHAREABLE))
  321                 return (EINVAL);
  322 
  323         /*
  324          * This does not support wholesale moving of a resource.  At
  325          * least part of the desired new range must overlap with the
  326          * existing resource.
  327          */
  328         if (end < r->r_start || r->r_end < start)
  329                 return (EINVAL);
  330 
  331         /*
  332          * Find the two resource regions immediately adjacent to the
  333          * allocated resource.
  334          */
  335         rm = r->r_rm;
  336         mtx_lock(rm->rm_mtx);
  337 #ifdef INVARIANTS
  338         TAILQ_FOREACH(s, &rm->rm_list, r_link) {
  339                 if (s == r)
  340                         break;
  341         }
  342         if (s == NULL)
  343                 panic("resource not in list");
  344 #endif
  345         s = TAILQ_PREV(r, resource_head, r_link);
  346         t = TAILQ_NEXT(r, r_link);
  347         KASSERT(s == NULL || s->r_end + 1 == r->r_start,
  348             ("prev resource mismatch"));
  349         KASSERT(t == NULL || r->r_end + 1 == t->r_start,
  350             ("next resource mismatch"));
  351 
  352         /*
  353          * See if the changes are permitted.  Shrinking is always allowed,
  354          * but growing requires sufficient room in the adjacent region.
  355          */
  356         if (start < r->r_start && (s == NULL || (s->r_flags & RF_ALLOCATED) ||
  357             s->r_start > start)) {
  358                 mtx_unlock(rm->rm_mtx);
  359                 return (EBUSY);
  360         }
  361         if (end > r->r_end && (t == NULL || (t->r_flags & RF_ALLOCATED) ||
  362             t->r_end < end)) {
  363                 mtx_unlock(rm->rm_mtx);
  364                 return (EBUSY);
  365         }
  366 
  367         /*
  368          * While holding the lock, grow either end of the resource as
  369          * needed and shrink either end if the shrinking does not require
  370          * allocating a new resource.  We can safely drop the lock and then
  371          * insert a new range to handle the shrinking case afterwards.
  372          */
  373         if (start < r->r_start ||
  374             (start > r->r_start && s != NULL && !(s->r_flags & RF_ALLOCATED))) {
  375                 KASSERT(s->r_flags == 0, ("prev is busy"));
  376                 r->r_start = start;
  377                 if (s->r_start == start) {
  378                         TAILQ_REMOVE(&rm->rm_list, s, r_link);
  379                         free(s, M_RMAN);
  380                 } else
  381                         s->r_end = start - 1;
  382         }
  383         if (end > r->r_end ||
  384             (end < r->r_end && t != NULL && !(t->r_flags & RF_ALLOCATED))) {
  385                 KASSERT(t->r_flags == 0, ("next is busy"));
  386                 r->r_end = end;
  387                 if (t->r_end == end) {
  388                         TAILQ_REMOVE(&rm->rm_list, t, r_link);
  389                         free(t, M_RMAN);
  390                 } else
  391                         t->r_start = end + 1;
  392         }
  393         mtx_unlock(rm->rm_mtx);
  394 
  395         /*
  396          * Handle the shrinking cases that require allocating a new
  397          * resource to hold the newly-free region.  We have to recheck
  398          * if we still need this new region after acquiring the lock.
  399          */
  400         if (start > r->r_start) {
  401                 new = int_alloc_resource(M_WAITOK);
  402                 new->r_start = r->r_start;
  403                 new->r_end = start - 1;
  404                 new->r_rm = rm;
  405                 mtx_lock(rm->rm_mtx);
  406                 r->r_start = start;
  407                 s = TAILQ_PREV(r, resource_head, r_link);
  408                 if (s != NULL && !(s->r_flags & RF_ALLOCATED)) {
  409                         s->r_end = start - 1;
  410                         free(new, M_RMAN);
  411                 } else
  412                         TAILQ_INSERT_BEFORE(r, new, r_link);
  413                 mtx_unlock(rm->rm_mtx);
  414         }
  415         if (end < r->r_end) {
  416                 new = int_alloc_resource(M_WAITOK);
  417                 new->r_start = end + 1;
  418                 new->r_end = r->r_end;
  419                 new->r_rm = rm;
  420                 mtx_lock(rm->rm_mtx);
  421                 r->r_end = end;
  422                 t = TAILQ_NEXT(r, r_link);
  423                 if (t != NULL && !(t->r_flags & RF_ALLOCATED)) {
  424                         t->r_start = end + 1;
  425                         free(new, M_RMAN);
  426                 } else
  427                         TAILQ_INSERT_AFTER(&rm->rm_list, r, new, r_link);
  428                 mtx_unlock(rm->rm_mtx);
  429         }
  430         return (0);
  431 }
  432 
  433 struct resource *
  434 rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end,
  435                       u_long count, u_long bound,  u_int flags,
  436                       struct device *dev)
  437 {
  438         u_int   want_activate;
  439         struct  resource_i *r, *s, *rv;
  440         u_long  rstart, rend, amask, bmask;
  441 
  442         rv = NULL;
  443 
  444         DPRINTF(("rman_reserve_resource_bound: <%s> request: [%#lx, %#lx], "
  445                "length %#lx, flags %u, device %s\n", rm->rm_descr, start, end,
  446                count, flags,
  447                dev == NULL ? "<null>" : device_get_nameunit(dev)));
  448         want_activate = (flags & RF_ACTIVE);
  449         flags &= ~RF_ACTIVE;
  450 
  451         mtx_lock(rm->rm_mtx);
  452 
  453         for (r = TAILQ_FIRST(&rm->rm_list);
  454              r && r->r_end < start;
  455              r = TAILQ_NEXT(r, r_link))
  456                 ;
  457 
  458         if (r == NULL) {
  459                 DPRINTF(("could not find a region\n"));
  460                 goto out;
  461         }
  462 
  463         amask = (1ul << RF_ALIGNMENT(flags)) - 1;
  464         /* If bound is 0, bmask will also be 0 */
  465         bmask = ~(bound - 1);
  466         /*
  467          * First try to find an acceptable totally-unshared region.
  468          */
  469         for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
  470                 DPRINTF(("considering [%#lx, %#lx]\n", s->r_start, s->r_end));
  471                 if (s->r_start + count - 1 > end) {
  472                         DPRINTF(("s->r_start (%#lx) + count - 1> end (%#lx)\n",
  473                             s->r_start, end));
  474                         break;
  475                 }
  476                 if (s->r_flags & RF_ALLOCATED) {
  477                         DPRINTF(("region is allocated\n"));
  478                         continue;
  479                 }
  480                 rstart = ulmax(s->r_start, start);
  481                 /*
  482                  * Try to find a region by adjusting to boundary and alignment
  483                  * until both conditions are satisfied. This is not an optimal
  484                  * algorithm, but in most cases it isn't really bad, either.
  485                  */
  486                 do {
  487                         rstart = (rstart + amask) & ~amask;
  488                         if (((rstart ^ (rstart + count - 1)) & bmask) != 0)
  489                                 rstart += bound - (rstart & ~bmask);
  490                 } while ((rstart & amask) != 0 && rstart < end &&
  491                     rstart < s->r_end);
  492                 rend = ulmin(s->r_end, ulmax(rstart + count - 1, end));
  493                 if (rstart > rend) {
  494                         DPRINTF(("adjusted start exceeds end\n"));
  495                         continue;
  496                 }
  497                 DPRINTF(("truncated region: [%#lx, %#lx]; size %#lx (requested %#lx)\n",
  498                        rstart, rend, (rend - rstart + 1), count));
  499 
  500                 if ((rend - rstart + 1) >= count) {
  501                         DPRINTF(("candidate region: [%#lx, %#lx], size %#lx\n",
  502                                rstart, rend, (rend - rstart + 1)));
  503                         if ((s->r_end - s->r_start + 1) == count) {
  504                                 DPRINTF(("candidate region is entire chunk\n"));
  505                                 rv = s;
  506                                 rv->r_flags |= RF_ALLOCATED | flags;
  507                                 rv->r_dev = dev;
  508                                 goto out;
  509                         }
  510 
  511                         /*
  512                          * If s->r_start < rstart and
  513                          *    s->r_end > rstart + count - 1, then
  514                          * we need to split the region into three pieces
  515                          * (the middle one will get returned to the user).
  516                          * Otherwise, we are allocating at either the
  517                          * beginning or the end of s, so we only need to
  518                          * split it in two.  The first case requires
  519                          * two new allocations; the second requires but one.
  520                          */
  521                         rv = int_alloc_resource(M_NOWAIT);
  522                         if (rv == NULL)
  523                                 goto out;
  524                         rv->r_start = rstart;
  525                         rv->r_end = rstart + count - 1;
  526                         rv->r_flags = flags | RF_ALLOCATED;
  527                         rv->r_dev = dev;
  528                         rv->r_rm = rm;
  529 
  530                         if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
  531                                 DPRINTF(("splitting region in three parts: "
  532                                        "[%#lx, %#lx]; [%#lx, %#lx]; [%#lx, %#lx]\n",
  533                                        s->r_start, rv->r_start - 1,
  534                                        rv->r_start, rv->r_end,
  535                                        rv->r_end + 1, s->r_end));
  536                                 /*
  537                                  * We are allocating in the middle.
  538                                  */
  539                                 r = int_alloc_resource(M_NOWAIT);
  540                                 if (r == NULL) {
  541                                         free(rv, M_RMAN);
  542                                         rv = NULL;
  543                                         goto out;
  544                                 }
  545                                 r->r_start = rv->r_end + 1;
  546                                 r->r_end = s->r_end;
  547                                 r->r_flags = s->r_flags;
  548                                 r->r_rm = rm;
  549                                 s->r_end = rv->r_start - 1;
  550                                 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
  551                                                      r_link);
  552                                 TAILQ_INSERT_AFTER(&rm->rm_list, rv, r,
  553                                                      r_link);
  554                         } else if (s->r_start == rv->r_start) {
  555                                 DPRINTF(("allocating from the beginning\n"));
  556                                 /*
  557                                  * We are allocating at the beginning.
  558                                  */
  559                                 s->r_start = rv->r_end + 1;
  560                                 TAILQ_INSERT_BEFORE(s, rv, r_link);
  561                         } else {
  562                                 DPRINTF(("allocating at the end\n"));
  563                                 /*
  564                                  * We are allocating at the end.
  565                                  */
  566                                 s->r_end = rv->r_start - 1;
  567                                 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
  568                                                      r_link);
  569                         }
  570                         goto out;
  571                 }
  572         }
  573 
  574         /*
  575          * Now find an acceptable shared region, if the client's requirements
  576          * allow sharing.  By our implementation restriction, a candidate
  577          * region must match exactly by both size and sharing type in order
  578          * to be considered compatible with the client's request.  (The
  579          * former restriction could probably be lifted without too much
  580          * additional work, but this does not seem warranted.)
  581          */
  582         DPRINTF(("no unshared regions found\n"));
  583         if ((flags & (RF_SHAREABLE | RF_TIMESHARE)) == 0)
  584                 goto out;
  585 
  586         for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
  587                 if (s->r_start > end)
  588                         break;
  589                 if ((s->r_flags & flags) != flags)
  590                         continue;
  591                 rstart = ulmax(s->r_start, start);
  592                 rend = ulmin(s->r_end, ulmax(start + count - 1, end));
  593                 if (s->r_start >= start && s->r_end <= end
  594                     && (s->r_end - s->r_start + 1) == count &&
  595                     (s->r_start & amask) == 0 &&
  596                     ((s->r_start ^ s->r_end) & bmask) == 0) {
  597                         rv = int_alloc_resource(M_NOWAIT);
  598                         if (rv == NULL)
  599                                 goto out;
  600                         rv->r_start = s->r_start;
  601                         rv->r_end = s->r_end;
  602                         rv->r_flags = s->r_flags &
  603                                 (RF_ALLOCATED | RF_SHAREABLE | RF_TIMESHARE);
  604                         rv->r_dev = dev;
  605                         rv->r_rm = rm;
  606                         if (s->r_sharehead == NULL) {
  607                                 s->r_sharehead = malloc(sizeof *s->r_sharehead,
  608                                                 M_RMAN, M_NOWAIT | M_ZERO);
  609                                 if (s->r_sharehead == NULL) {
  610                                         free(rv, M_RMAN);
  611                                         rv = NULL;
  612                                         goto out;
  613                                 }
  614                                 LIST_INIT(s->r_sharehead);
  615                                 LIST_INSERT_HEAD(s->r_sharehead, s,
  616                                                  r_sharelink);
  617                                 s->r_flags |= RF_FIRSTSHARE;
  618                         }
  619                         rv->r_sharehead = s->r_sharehead;
  620                         LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
  621                         goto out;
  622                 }
  623         }
  624 
  625         /*
  626          * We couldn't find anything.
  627          */
  628 out:
  629         /*
  630          * If the user specified RF_ACTIVE in the initial flags,
  631          * which is reflected in `want_activate', we attempt to atomically
  632          * activate the resource.  If this fails, we release the resource
  633          * and indicate overall failure.  (This behavior probably doesn't
  634          * make sense for RF_TIMESHARE-type resources.)
  635          */
  636         if (rv && want_activate) {
  637                 struct resource_i *whohas;
  638                 if (int_rman_activate_resource(rm, rv, &whohas)) {
  639                         int_rman_release_resource(rm, rv);
  640                         rv = NULL;
  641                 }
  642         }
  643 
  644         mtx_unlock(rm->rm_mtx);
  645         return (rv == NULL ? NULL : &rv->r_r);
  646 }
  647 
  648 struct resource *
  649 rman_reserve_resource(struct rman *rm, u_long start, u_long end, u_long count,
  650                       u_int flags, struct device *dev)
  651 {
  652 
  653         return (rman_reserve_resource_bound(rm, start, end, count, 0, flags,
  654             dev));
  655 }
  656 
  657 static int
  658 int_rman_activate_resource(struct rman *rm, struct resource_i *r,
  659                            struct resource_i **whohas)
  660 {
  661         struct resource_i *s;
  662         int ok;
  663 
  664         /*
  665          * If we are not timesharing, then there is nothing much to do.
  666          * If we already have the resource, then there is nothing at all to do.
  667          * If we are not on a sharing list with anybody else, then there is
  668          * little to do.
  669          */
  670         if ((r->r_flags & RF_TIMESHARE) == 0
  671             || (r->r_flags & RF_ACTIVE) != 0
  672             || r->r_sharehead == NULL) {
  673                 r->r_flags |= RF_ACTIVE;
  674                 return 0;
  675         }
  676 
  677         ok = 1;
  678         for (s = LIST_FIRST(r->r_sharehead); s && ok;
  679              s = LIST_NEXT(s, r_sharelink)) {
  680                 if ((s->r_flags & RF_ACTIVE) != 0) {
  681                         ok = 0;
  682                         *whohas = s;
  683                 }
  684         }
  685         if (ok) {
  686                 r->r_flags |= RF_ACTIVE;
  687                 return 0;
  688         }
  689         return EBUSY;
  690 }
  691 
  692 int
  693 rman_activate_resource(struct resource *re)
  694 {
  695         int rv;
  696         struct resource_i *r, *whohas;
  697         struct rman *rm;
  698 
  699         r = re->__r_i;
  700         rm = r->r_rm;
  701         mtx_lock(rm->rm_mtx);
  702         rv = int_rman_activate_resource(rm, r, &whohas);
  703         mtx_unlock(rm->rm_mtx);
  704         return rv;
  705 }
  706 
  707 int
  708 rman_await_resource(struct resource *re, int pri, int timo)
  709 {
  710         int     rv;
  711         struct  resource_i *r, *whohas;
  712         struct  rman *rm;
  713 
  714         r = re->__r_i;
  715         rm = r->r_rm;
  716         mtx_lock(rm->rm_mtx);
  717         for (;;) {
  718                 rv = int_rman_activate_resource(rm, r, &whohas);
  719                 if (rv != EBUSY)
  720                         return (rv);    /* returns with mutex held */
  721 
  722                 if (r->r_sharehead == NULL)
  723                         panic("rman_await_resource");
  724                 whohas->r_flags |= RF_WANTED;
  725                 rv = msleep(r->r_sharehead, rm->rm_mtx, pri, "rmwait", timo);
  726                 if (rv) {
  727                         mtx_unlock(rm->rm_mtx);
  728                         return (rv);
  729                 }
  730         }
  731 }
  732 
  733 static int
  734 int_rman_deactivate_resource(struct resource_i *r)
  735 {
  736 
  737         r->r_flags &= ~RF_ACTIVE;
  738         if (r->r_flags & RF_WANTED) {
  739                 r->r_flags &= ~RF_WANTED;
  740                 wakeup(r->r_sharehead);
  741         }
  742         return 0;
  743 }
  744 
  745 int
  746 rman_deactivate_resource(struct resource *r)
  747 {
  748         struct  rman *rm;
  749 
  750         rm = r->__r_i->r_rm;
  751         mtx_lock(rm->rm_mtx);
  752         int_rman_deactivate_resource(r->__r_i);
  753         mtx_unlock(rm->rm_mtx);
  754         return 0;
  755 }
  756 
  757 static int
  758 int_rman_release_resource(struct rman *rm, struct resource_i *r)
  759 {
  760         struct  resource_i *s, *t;
  761 
  762         if (r->r_flags & RF_ACTIVE)
  763                 int_rman_deactivate_resource(r);
  764 
  765         /*
  766          * Check for a sharing list first.  If there is one, then we don't
  767          * have to think as hard.
  768          */
  769         if (r->r_sharehead) {
  770                 /*
  771                  * If a sharing list exists, then we know there are at
  772                  * least two sharers.
  773                  *
  774                  * If we are in the main circleq, appoint someone else.
  775                  */
  776                 LIST_REMOVE(r, r_sharelink);
  777                 s = LIST_FIRST(r->r_sharehead);
  778                 if (r->r_flags & RF_FIRSTSHARE) {
  779                         s->r_flags |= RF_FIRSTSHARE;
  780                         TAILQ_INSERT_BEFORE(r, s, r_link);
  781                         TAILQ_REMOVE(&rm->rm_list, r, r_link);
  782                 }
  783 
  784                 /*
  785                  * Make sure that the sharing list goes away completely
  786                  * if the resource is no longer being shared at all.
  787                  */
  788                 if (LIST_NEXT(s, r_sharelink) == NULL) {
  789                         free(s->r_sharehead, M_RMAN);
  790                         s->r_sharehead = NULL;
  791                         s->r_flags &= ~RF_FIRSTSHARE;
  792                 }
  793                 goto out;
  794         }
  795 
  796         /*
  797          * Look at the adjacent resources in the list and see if our
  798          * segment can be merged with any of them.  If either of the
  799          * resources is allocated or is not exactly adjacent then they
  800          * cannot be merged with our segment.
  801          */
  802         s = TAILQ_PREV(r, resource_head, r_link);
  803         if (s != NULL && ((s->r_flags & RF_ALLOCATED) != 0 ||
  804             s->r_end + 1 != r->r_start))
  805                 s = NULL;
  806         t = TAILQ_NEXT(r, r_link);
  807         if (t != NULL && ((t->r_flags & RF_ALLOCATED) != 0 ||
  808             r->r_end + 1 != t->r_start))
  809                 t = NULL;
  810 
  811         if (s != NULL && t != NULL) {
  812                 /*
  813                  * Merge all three segments.
  814                  */
  815                 s->r_end = t->r_end;
  816                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  817                 TAILQ_REMOVE(&rm->rm_list, t, r_link);
  818                 free(t, M_RMAN);
  819         } else if (s != NULL) {
  820                 /*
  821                  * Merge previous segment with ours.
  822                  */
  823                 s->r_end = r->r_end;
  824                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  825         } else if (t != NULL) {
  826                 /*
  827                  * Merge next segment with ours.
  828                  */
  829                 t->r_start = r->r_start;
  830                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  831         } else {
  832                 /*
  833                  * At this point, we know there is nothing we
  834                  * can potentially merge with, because on each
  835                  * side, there is either nothing there or what is
  836                  * there is still allocated.  In that case, we don't
  837                  * want to remove r from the list; we simply want to
  838                  * change it to an unallocated region and return
  839                  * without freeing anything.
  840                  */
  841                 r->r_flags &= ~RF_ALLOCATED;
  842                 r->r_dev = NULL;
  843                 return 0;
  844         }
  845 
  846 out:
  847         free(r, M_RMAN);
  848         return 0;
  849 }
  850 
  851 int
  852 rman_release_resource(struct resource *re)
  853 {
  854         int     rv;
  855         struct  resource_i *r;
  856         struct  rman *rm;
  857 
  858         r = re->__r_i;
  859         rm = r->r_rm;
  860         mtx_lock(rm->rm_mtx);
  861         rv = int_rman_release_resource(rm, r);
  862         mtx_unlock(rm->rm_mtx);
  863         return (rv);
  864 }
  865 
  866 uint32_t
  867 rman_make_alignment_flags(uint32_t size)
  868 {
  869         int     i;
  870 
  871         /*
  872          * Find the hightest bit set, and add one if more than one bit
  873          * set.  We're effectively computing the ceil(log2(size)) here.
  874          */
  875         for (i = 31; i > 0; i--)
  876                 if ((1 << i) & size)
  877                         break;
  878         if (~(1 << i) & size)
  879                 i++;
  880 
  881         return(RF_ALIGNMENT_LOG2(i));
  882 }
  883 
  884 void
  885 rman_set_start(struct resource *r, u_long start)
  886 {
  887         r->__r_i->r_start = start;
  888 }
  889 
  890 u_long
  891 rman_get_start(struct resource *r)
  892 {
  893         return (r->__r_i->r_start);
  894 }
  895 
  896 void
  897 rman_set_end(struct resource *r, u_long end)
  898 {
  899         r->__r_i->r_end = end;
  900 }
  901 
  902 u_long
  903 rman_get_end(struct resource *r)
  904 {
  905         return (r->__r_i->r_end);
  906 }
  907 
  908 u_long
  909 rman_get_size(struct resource *r)
  910 {
  911         return (r->__r_i->r_end - r->__r_i->r_start + 1);
  912 }
  913 
  914 u_int
  915 rman_get_flags(struct resource *r)
  916 {
  917         return (r->__r_i->r_flags);
  918 }
  919 
  920 void
  921 rman_set_virtual(struct resource *r, void *v)
  922 {
  923         r->__r_i->r_virtual = v;
  924 }
  925 
  926 void *
  927 rman_get_virtual(struct resource *r)
  928 {
  929         return (r->__r_i->r_virtual);
  930 }
  931 
  932 void
  933 rman_set_bustag(struct resource *r, bus_space_tag_t t)
  934 {
  935         r->r_bustag = t;
  936 }
  937 
  938 bus_space_tag_t
  939 rman_get_bustag(struct resource *r)
  940 {
  941         return (r->r_bustag);
  942 }
  943 
  944 void
  945 rman_set_bushandle(struct resource *r, bus_space_handle_t h)
  946 {
  947         r->r_bushandle = h;
  948 }
  949 
  950 bus_space_handle_t
  951 rman_get_bushandle(struct resource *r)
  952 {
  953         return (r->r_bushandle);
  954 }
  955 
  956 void
  957 rman_set_rid(struct resource *r, int rid)
  958 {
  959         r->__r_i->r_rid = rid;
  960 }
  961 
  962 int
  963 rman_get_rid(struct resource *r)
  964 {
  965         return (r->__r_i->r_rid);
  966 }
  967 
  968 void
  969 rman_set_device(struct resource *r, struct device *dev)
  970 {
  971         r->__r_i->r_dev = dev;
  972 }
  973 
  974 struct device *
  975 rman_get_device(struct resource *r)
  976 {
  977         return (r->__r_i->r_dev);
  978 }
  979 
  980 int
  981 rman_is_region_manager(struct resource *r, struct rman *rm)
  982 {
  983 
  984         return (r->__r_i->r_rm == rm);
  985 }
  986 
  987 /*
  988  * Sysctl interface for scanning the resource lists.
  989  *
  990  * We take two input parameters; the index into the list of resource
  991  * managers, and the resource offset into the list.
  992  */
  993 static int
  994 sysctl_rman(SYSCTL_HANDLER_ARGS)
  995 {
  996         int                     *name = (int *)arg1;
  997         u_int                   namelen = arg2;
  998         int                     rman_idx, res_idx;
  999         struct rman             *rm;
 1000         struct resource_i       *res;
 1001         struct resource_i       *sres;
 1002         struct u_rman           urm;
 1003         struct u_resource       ures;
 1004         int                     error;
 1005 
 1006         if (namelen != 3)
 1007                 return (EINVAL);
 1008 
 1009         if (bus_data_generation_check(name[0]))
 1010                 return (EINVAL);
 1011         rman_idx = name[1];
 1012         res_idx = name[2];
 1013 
 1014         /*
 1015          * Find the indexed resource manager
 1016          */
 1017         mtx_lock(&rman_mtx);
 1018         TAILQ_FOREACH(rm, &rman_head, rm_link) {
 1019                 if (rman_idx-- == 0)
 1020                         break;
 1021         }
 1022         mtx_unlock(&rman_mtx);
 1023         if (rm == NULL)
 1024                 return (ENOENT);
 1025 
 1026         /*
 1027          * If the resource index is -1, we want details on the
 1028          * resource manager.
 1029          */
 1030         if (res_idx == -1) {
 1031                 bzero(&urm, sizeof(urm));
 1032                 urm.rm_handle = (uintptr_t)rm;
 1033                 if (rm->rm_descr != NULL)
 1034                         strlcpy(urm.rm_descr, rm->rm_descr, RM_TEXTLEN);
 1035                 urm.rm_start = rm->rm_start;
 1036                 urm.rm_size = rm->rm_end - rm->rm_start + 1;
 1037                 urm.rm_type = rm->rm_type;
 1038 
 1039                 error = SYSCTL_OUT(req, &urm, sizeof(urm));
 1040                 return (error);
 1041         }
 1042 
 1043         /*
 1044          * Find the indexed resource and return it.
 1045          */
 1046         mtx_lock(rm->rm_mtx);
 1047         TAILQ_FOREACH(res, &rm->rm_list, r_link) {
 1048                 if (res->r_sharehead != NULL) {
 1049                         LIST_FOREACH(sres, res->r_sharehead, r_sharelink)
 1050                                 if (res_idx-- == 0) {
 1051                                         res = sres;
 1052                                         goto found;
 1053                                 }
 1054                 }
 1055                 else if (res_idx-- == 0)
 1056                                 goto found;
 1057         }
 1058         mtx_unlock(rm->rm_mtx);
 1059         return (ENOENT);
 1060 
 1061 found:
 1062         bzero(&ures, sizeof(ures));
 1063         ures.r_handle = (uintptr_t)res;
 1064         ures.r_parent = (uintptr_t)res->r_rm;
 1065         ures.r_device = (uintptr_t)res->r_dev;
 1066         if (res->r_dev != NULL) {
 1067                 if (device_get_name(res->r_dev) != NULL) {
 1068                         snprintf(ures.r_devname, RM_TEXTLEN,
 1069                             "%s%d",
 1070                             device_get_name(res->r_dev),
 1071                             device_get_unit(res->r_dev));
 1072                 } else {
 1073                         strlcpy(ures.r_devname, "nomatch",
 1074                             RM_TEXTLEN);
 1075                 }
 1076         } else {
 1077                 ures.r_devname[0] = '\0';
 1078         }
 1079         ures.r_start = res->r_start;
 1080         ures.r_size = res->r_end - res->r_start + 1;
 1081         ures.r_flags = res->r_flags;
 1082 
 1083         mtx_unlock(rm->rm_mtx);
 1084         error = SYSCTL_OUT(req, &ures, sizeof(ures));
 1085         return (error);
 1086 }
 1087 
 1088 SYSCTL_NODE(_hw_bus, OID_AUTO, rman, CTLFLAG_RD, sysctl_rman,
 1089     "kernel resource manager");
 1090 
 1091 #ifdef DDB
 1092 static void
 1093 dump_rman(struct rman *rm)
 1094 {
 1095         struct resource_i *r;
 1096         const char *devname;
 1097 
 1098         if (db_pager_quit)
 1099                 return;
 1100         db_printf("rman: %s\n", rm->rm_descr);
 1101         db_printf("    0x%lx-0x%lx (full range)\n", rm->rm_start, rm->rm_end);
 1102         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
 1103                 if (r->r_dev != NULL) {
 1104                         devname = device_get_nameunit(r->r_dev);
 1105                         if (devname == NULL)
 1106                                 devname = "nomatch";
 1107                 } else
 1108                         devname = NULL;
 1109                 db_printf("    0x%lx-0x%lx ", r->r_start, r->r_end);
 1110                 if (devname != NULL)
 1111                         db_printf("(%s)\n", devname);
 1112                 else
 1113                         db_printf("----\n");
 1114                 if (db_pager_quit)
 1115                         return;
 1116         }
 1117 }
 1118 
 1119 DB_SHOW_COMMAND(rman, db_show_rman)
 1120 {
 1121 
 1122         if (have_addr)
 1123                 dump_rman((struct rman *)addr);
 1124 }
 1125 
 1126 DB_SHOW_ALL_COMMAND(rman, db_show_all_rman)
 1127 {
 1128         struct rman *rm;
 1129 
 1130         TAILQ_FOREACH(rm, &rman_head, rm_link)
 1131                 dump_rman(rm);
 1132 }
 1133 DB_SHOW_ALIAS(allrman, db_show_all_rman);
 1134 #endif

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