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/11.0/sys/kern/subr_rman.c 300317 2016-05-20 17:57:47Z 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         rman_res_t      r_start;        /* index of the first entry in this resource */
   94         rman_res_t      r_end;          /* index of the last entry (inclusive) */
   95         u_int   r_flags;
   96         void    *r_virtual;     /* virtual address of this resource */
   97         device_t 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 SYSCTL_INT(_debug, OID_AUTO, rman_debug, CTLFLAG_RWTUN,
  104     &rman_debug, 0, "rman debug");
  105 
  106 #define DPRINTF(params) if (rman_debug) printf params
  107 
  108 static MALLOC_DEFINE(M_RMAN, "rman", "Resource manager");
  109 
  110 struct rman_head rman_head;
  111 static struct mtx rman_mtx; /* mutex to protect rman_head */
  112 static int int_rman_release_resource(struct rman *rm, struct resource_i *r);
  113 
  114 static __inline struct resource_i *
  115 int_alloc_resource(int malloc_flag)
  116 {
  117         struct resource_i *r;
  118 
  119         r = malloc(sizeof *r, M_RMAN, malloc_flag | M_ZERO);
  120         if (r != NULL) {
  121                 r->r_r.__r_i = r;
  122         }
  123         return (r);
  124 }
  125 
  126 int
  127 rman_init(struct rman *rm)
  128 {
  129         static int once = 0;
  130 
  131         if (once == 0) {
  132                 once = 1;
  133                 TAILQ_INIT(&rman_head);
  134                 mtx_init(&rman_mtx, "rman head", NULL, MTX_DEF);
  135         }
  136 
  137         if (rm->rm_start == 0 && rm->rm_end == 0)
  138                 rm->rm_end = ~0;
  139         if (rm->rm_type == RMAN_UNINIT)
  140                 panic("rman_init");
  141         if (rm->rm_type == RMAN_GAUGE)
  142                 panic("implement RMAN_GAUGE");
  143 
  144         TAILQ_INIT(&rm->rm_list);
  145         rm->rm_mtx = malloc(sizeof *rm->rm_mtx, M_RMAN, M_NOWAIT | M_ZERO);
  146         if (rm->rm_mtx == NULL)
  147                 return ENOMEM;
  148         mtx_init(rm->rm_mtx, "rman", NULL, MTX_DEF);
  149 
  150         mtx_lock(&rman_mtx);
  151         TAILQ_INSERT_TAIL(&rman_head, rm, rm_link);
  152         mtx_unlock(&rman_mtx);
  153         return 0;
  154 }
  155 
  156 int
  157 rman_manage_region(struct rman *rm, rman_res_t start, rman_res_t end)
  158 {
  159         struct resource_i *r, *s, *t;
  160         int rv = 0;
  161 
  162         DPRINTF(("rman_manage_region: <%s> request: start %#jx, end %#jx\n",
  163             rm->rm_descr, start, end));
  164         if (start < rm->rm_start || end > rm->rm_end)
  165                 return EINVAL;
  166         r = int_alloc_resource(M_NOWAIT);
  167         if (r == NULL)
  168                 return ENOMEM;
  169         r->r_start = start;
  170         r->r_end = end;
  171         r->r_rm = rm;
  172 
  173         mtx_lock(rm->rm_mtx);
  174 
  175         /* Skip entries before us. */
  176         TAILQ_FOREACH(s, &rm->rm_list, r_link) {
  177                 if (s->r_end == ~0)
  178                         break;
  179                 if (s->r_end + 1 >= r->r_start)
  180                         break;
  181         }
  182 
  183         /* If we ran off the end of the list, insert at the tail. */
  184         if (s == NULL) {
  185                 TAILQ_INSERT_TAIL(&rm->rm_list, r, r_link);
  186         } else {
  187                 /* Check for any overlap with the current region. */
  188                 if (r->r_start <= s->r_end && r->r_end >= s->r_start) {
  189                         rv = EBUSY;
  190                         goto out;
  191                 }
  192 
  193                 /* Check for any overlap with the next region. */
  194                 t = TAILQ_NEXT(s, r_link);
  195                 if (t && r->r_start <= t->r_end && r->r_end >= t->r_start) {
  196                         rv = EBUSY;
  197                         goto out;
  198                 }
  199 
  200                 /*
  201                  * See if this region can be merged with the next region.  If
  202                  * not, clear the pointer.
  203                  */
  204                 if (t && (r->r_end + 1 != t->r_start || t->r_flags != 0))
  205                         t = NULL;
  206 
  207                 /* See if we can merge with the current region. */
  208                 if (s->r_end + 1 == r->r_start && s->r_flags == 0) {
  209                         /* Can we merge all 3 regions? */
  210                         if (t != NULL) {
  211                                 s->r_end = t->r_end;
  212                                 TAILQ_REMOVE(&rm->rm_list, t, r_link);
  213                                 free(r, M_RMAN);
  214                                 free(t, M_RMAN);
  215                         } else {
  216                                 s->r_end = r->r_end;
  217                                 free(r, M_RMAN);
  218                         }
  219                 } else if (t != NULL) {
  220                         /* Can we merge with just the next region? */
  221                         t->r_start = r->r_start;
  222                         free(r, M_RMAN);
  223                 } else if (s->r_end < r->r_start) {
  224                         TAILQ_INSERT_AFTER(&rm->rm_list, s, r, r_link);
  225                 } else {
  226                         TAILQ_INSERT_BEFORE(s, r, r_link);
  227                 }
  228         }
  229 out:
  230         mtx_unlock(rm->rm_mtx);
  231         return rv;
  232 }
  233 
  234 int
  235 rman_init_from_resource(struct rman *rm, struct resource *r)
  236 {
  237         int rv;
  238 
  239         if ((rv = rman_init(rm)) != 0)
  240                 return (rv);
  241         return (rman_manage_region(rm, r->__r_i->r_start, r->__r_i->r_end));
  242 }
  243 
  244 int
  245 rman_fini(struct rman *rm)
  246 {
  247         struct resource_i *r;
  248 
  249         mtx_lock(rm->rm_mtx);
  250         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
  251                 if (r->r_flags & RF_ALLOCATED) {
  252                         mtx_unlock(rm->rm_mtx);
  253                         return EBUSY;
  254                 }
  255         }
  256 
  257         /*
  258          * There really should only be one of these if we are in this
  259          * state and the code is working properly, but it can't hurt.
  260          */
  261         while (!TAILQ_EMPTY(&rm->rm_list)) {
  262                 r = TAILQ_FIRST(&rm->rm_list);
  263                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  264                 free(r, M_RMAN);
  265         }
  266         mtx_unlock(rm->rm_mtx);
  267         mtx_lock(&rman_mtx);
  268         TAILQ_REMOVE(&rman_head, rm, rm_link);
  269         mtx_unlock(&rman_mtx);
  270         mtx_destroy(rm->rm_mtx);
  271         free(rm->rm_mtx, M_RMAN);
  272 
  273         return 0;
  274 }
  275 
  276 int
  277 rman_first_free_region(struct rman *rm, rman_res_t *start, rman_res_t *end)
  278 {
  279         struct resource_i *r;
  280 
  281         mtx_lock(rm->rm_mtx);
  282         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
  283                 if (!(r->r_flags & RF_ALLOCATED)) {
  284                         *start = r->r_start;
  285                         *end = r->r_end;
  286                         mtx_unlock(rm->rm_mtx);
  287                         return (0);
  288                 }
  289         }
  290         mtx_unlock(rm->rm_mtx);
  291         return (ENOENT);
  292 }
  293 
  294 int
  295 rman_last_free_region(struct rman *rm, rman_res_t *start, rman_res_t *end)
  296 {
  297         struct resource_i *r;
  298 
  299         mtx_lock(rm->rm_mtx);
  300         TAILQ_FOREACH_REVERSE(r, &rm->rm_list, resource_head, r_link) {
  301                 if (!(r->r_flags & RF_ALLOCATED)) {
  302                         *start = r->r_start;
  303                         *end = r->r_end;
  304                         mtx_unlock(rm->rm_mtx);
  305                         return (0);
  306                 }
  307         }
  308         mtx_unlock(rm->rm_mtx);
  309         return (ENOENT);
  310 }
  311 
  312 /* Shrink or extend one or both ends of an allocated resource. */
  313 int
  314 rman_adjust_resource(struct resource *rr, rman_res_t start, rman_res_t end)
  315 {
  316         struct resource_i *r, *s, *t, *new;
  317         struct rman *rm;
  318 
  319         /* Not supported for shared resources. */
  320         r = rr->__r_i;
  321         if (r->r_flags & RF_SHAREABLE)
  322                 return (EINVAL);
  323 
  324         /*
  325          * This does not support wholesale moving of a resource.  At
  326          * least part of the desired new range must overlap with the
  327          * existing resource.
  328          */
  329         if (end < r->r_start || r->r_end < start)
  330                 return (EINVAL);
  331 
  332         /*
  333          * Find the two resource regions immediately adjacent to the
  334          * allocated resource.
  335          */
  336         rm = r->r_rm;
  337         mtx_lock(rm->rm_mtx);
  338 #ifdef INVARIANTS
  339         TAILQ_FOREACH(s, &rm->rm_list, r_link) {
  340                 if (s == r)
  341                         break;
  342         }
  343         if (s == NULL)
  344                 panic("resource not in list");
  345 #endif
  346         s = TAILQ_PREV(r, resource_head, r_link);
  347         t = TAILQ_NEXT(r, r_link);
  348         KASSERT(s == NULL || s->r_end + 1 == r->r_start,
  349             ("prev resource mismatch"));
  350         KASSERT(t == NULL || r->r_end + 1 == t->r_start,
  351             ("next resource mismatch"));
  352 
  353         /*
  354          * See if the changes are permitted.  Shrinking is always allowed,
  355          * but growing requires sufficient room in the adjacent region.
  356          */
  357         if (start < r->r_start && (s == NULL || (s->r_flags & RF_ALLOCATED) ||
  358             s->r_start > start)) {
  359                 mtx_unlock(rm->rm_mtx);
  360                 return (EBUSY);
  361         }
  362         if (end > r->r_end && (t == NULL || (t->r_flags & RF_ALLOCATED) ||
  363             t->r_end < end)) {
  364                 mtx_unlock(rm->rm_mtx);
  365                 return (EBUSY);
  366         }
  367 
  368         /*
  369          * While holding the lock, grow either end of the resource as
  370          * needed and shrink either end if the shrinking does not require
  371          * allocating a new resource.  We can safely drop the lock and then
  372          * insert a new range to handle the shrinking case afterwards.
  373          */
  374         if (start < r->r_start ||
  375             (start > r->r_start && s != NULL && !(s->r_flags & RF_ALLOCATED))) {
  376                 KASSERT(s->r_flags == 0, ("prev is busy"));
  377                 r->r_start = start;
  378                 if (s->r_start == start) {
  379                         TAILQ_REMOVE(&rm->rm_list, s, r_link);
  380                         free(s, M_RMAN);
  381                 } else
  382                         s->r_end = start - 1;
  383         }
  384         if (end > r->r_end ||
  385             (end < r->r_end && t != NULL && !(t->r_flags & RF_ALLOCATED))) {
  386                 KASSERT(t->r_flags == 0, ("next is busy"));
  387                 r->r_end = end;
  388                 if (t->r_end == end) {
  389                         TAILQ_REMOVE(&rm->rm_list, t, r_link);
  390                         free(t, M_RMAN);
  391                 } else
  392                         t->r_start = end + 1;
  393         }
  394         mtx_unlock(rm->rm_mtx);
  395 
  396         /*
  397          * Handle the shrinking cases that require allocating a new
  398          * resource to hold the newly-free region.  We have to recheck
  399          * if we still need this new region after acquiring the lock.
  400          */
  401         if (start > r->r_start) {
  402                 new = int_alloc_resource(M_WAITOK);
  403                 new->r_start = r->r_start;
  404                 new->r_end = start - 1;
  405                 new->r_rm = rm;
  406                 mtx_lock(rm->rm_mtx);
  407                 r->r_start = start;
  408                 s = TAILQ_PREV(r, resource_head, r_link);
  409                 if (s != NULL && !(s->r_flags & RF_ALLOCATED)) {
  410                         s->r_end = start - 1;
  411                         free(new, M_RMAN);
  412                 } else
  413                         TAILQ_INSERT_BEFORE(r, new, r_link);
  414                 mtx_unlock(rm->rm_mtx);
  415         }
  416         if (end < r->r_end) {
  417                 new = int_alloc_resource(M_WAITOK);
  418                 new->r_start = end + 1;
  419                 new->r_end = r->r_end;
  420                 new->r_rm = rm;
  421                 mtx_lock(rm->rm_mtx);
  422                 r->r_end = end;
  423                 t = TAILQ_NEXT(r, r_link);
  424                 if (t != NULL && !(t->r_flags & RF_ALLOCATED)) {
  425                         t->r_start = end + 1;
  426                         free(new, M_RMAN);
  427                 } else
  428                         TAILQ_INSERT_AFTER(&rm->rm_list, r, new, r_link);
  429                 mtx_unlock(rm->rm_mtx);
  430         }
  431         return (0);
  432 }
  433 
  434 #define SHARE_TYPE(f)   (f & (RF_SHAREABLE | RF_PREFETCHABLE))
  435 
  436 struct resource *
  437 rman_reserve_resource_bound(struct rman *rm, rman_res_t start, rman_res_t end,
  438                             rman_res_t count, rman_res_t bound, u_int flags,
  439                             device_t dev)
  440 {
  441         u_int new_rflags;
  442         struct resource_i *r, *s, *rv;
  443         rman_res_t rstart, rend, amask, bmask;
  444 
  445         rv = NULL;
  446 
  447         DPRINTF(("rman_reserve_resource_bound: <%s> request: [%#jx, %#jx], "
  448                "length %#jx, flags %x, device %s\n", rm->rm_descr, start, end,
  449                count, flags,
  450                dev == NULL ? "<null>" : device_get_nameunit(dev)));
  451         KASSERT((flags & RF_FIRSTSHARE) == 0,
  452             ("invalid flags %#x", flags));
  453         new_rflags = (flags & ~RF_FIRSTSHARE) | RF_ALLOCATED;
  454 
  455         mtx_lock(rm->rm_mtx);
  456 
  457         r = TAILQ_FIRST(&rm->rm_list);
  458         if (r == NULL) {
  459             DPRINTF(("NULL list head\n"));
  460         } else {
  461             DPRINTF(("rman_reserve_resource_bound: trying %#jx <%#jx,%#jx>\n",
  462                     r->r_end, start, count-1));
  463         }
  464         for (r = TAILQ_FIRST(&rm->rm_list);
  465              r && r->r_end < start + count - 1;
  466              r = TAILQ_NEXT(r, r_link)) {
  467                 ;
  468                 DPRINTF(("rman_reserve_resource_bound: tried %#jx <%#jx,%#jx>\n",
  469                         r->r_end, start, count-1));
  470         }
  471 
  472         if (r == NULL) {
  473                 DPRINTF(("could not find a region\n"));
  474                 goto out;
  475         }
  476 
  477         amask = (1ull << RF_ALIGNMENT(flags)) - 1;
  478         KASSERT(start <= RM_MAX_END - amask,
  479             ("start (%#jx) + amask (%#jx) would wrap around", start, amask));
  480 
  481         /* If bound is 0, bmask will also be 0 */
  482         bmask = ~(bound - 1);
  483         /*
  484          * First try to find an acceptable totally-unshared region.
  485          */
  486         for (s = r; s; s = TAILQ_NEXT(s, r_link)) {
  487                 DPRINTF(("considering [%#jx, %#jx]\n", s->r_start, s->r_end));
  488                 /*
  489                  * The resource list is sorted, so there is no point in
  490                  * searching further once r_start is too large.
  491                  */
  492                 if (s->r_start > end - (count - 1)) {
  493                         DPRINTF(("s->r_start (%#jx) + count - 1> end (%#jx)\n",
  494                             s->r_start, end));
  495                         break;
  496                 }
  497                 if (s->r_start > RM_MAX_END - amask) {
  498                         DPRINTF(("s->r_start (%#jx) + amask (%#jx) too large\n",
  499                             s->r_start, amask));
  500                         break;
  501                 }
  502                 if (s->r_flags & RF_ALLOCATED) {
  503                         DPRINTF(("region is allocated\n"));
  504                         continue;
  505                 }
  506                 rstart = ummax(s->r_start, start);
  507                 /*
  508                  * Try to find a region by adjusting to boundary and alignment
  509                  * until both conditions are satisfied. This is not an optimal
  510                  * algorithm, but in most cases it isn't really bad, either.
  511                  */
  512                 do {
  513                         rstart = (rstart + amask) & ~amask;
  514                         if (((rstart ^ (rstart + count - 1)) & bmask) != 0)
  515                                 rstart += bound - (rstart & ~bmask);
  516                 } while ((rstart & amask) != 0 && rstart < end &&
  517                     rstart < s->r_end);
  518                 rend = ummin(s->r_end, ummax(rstart + count - 1, end));
  519                 if (rstart > rend) {
  520                         DPRINTF(("adjusted start exceeds end\n"));
  521                         continue;
  522                 }
  523                 DPRINTF(("truncated region: [%#jx, %#jx]; size %#jx (requested %#jx)\n",
  524                        rstart, rend, (rend - rstart + 1), count));
  525 
  526                 if ((rend - rstart + 1) >= count) {
  527                         DPRINTF(("candidate region: [%#jx, %#jx], size %#jx\n",
  528                                rstart, rend, (rend - rstart + 1)));
  529                         if ((s->r_end - s->r_start + 1) == count) {
  530                                 DPRINTF(("candidate region is entire chunk\n"));
  531                                 rv = s;
  532                                 rv->r_flags = new_rflags;
  533                                 rv->r_dev = dev;
  534                                 goto out;
  535                         }
  536 
  537                         /*
  538                          * If s->r_start < rstart and
  539                          *    s->r_end > rstart + count - 1, then
  540                          * we need to split the region into three pieces
  541                          * (the middle one will get returned to the user).
  542                          * Otherwise, we are allocating at either the
  543                          * beginning or the end of s, so we only need to
  544                          * split it in two.  The first case requires
  545                          * two new allocations; the second requires but one.
  546                          */
  547                         rv = int_alloc_resource(M_NOWAIT);
  548                         if (rv == NULL)
  549                                 goto out;
  550                         rv->r_start = rstart;
  551                         rv->r_end = rstart + count - 1;
  552                         rv->r_flags = new_rflags;
  553                         rv->r_dev = dev;
  554                         rv->r_rm = rm;
  555 
  556                         if (s->r_start < rv->r_start && s->r_end > rv->r_end) {
  557                                 DPRINTF(("splitting region in three parts: "
  558                                        "[%#jx, %#jx]; [%#jx, %#jx]; [%#jx, %#jx]\n",
  559                                        s->r_start, rv->r_start - 1,
  560                                        rv->r_start, rv->r_end,
  561                                        rv->r_end + 1, s->r_end));
  562                                 /*
  563                                  * We are allocating in the middle.
  564                                  */
  565                                 r = int_alloc_resource(M_NOWAIT);
  566                                 if (r == NULL) {
  567                                         free(rv, M_RMAN);
  568                                         rv = NULL;
  569                                         goto out;
  570                                 }
  571                                 r->r_start = rv->r_end + 1;
  572                                 r->r_end = s->r_end;
  573                                 r->r_flags = s->r_flags;
  574                                 r->r_rm = rm;
  575                                 s->r_end = rv->r_start - 1;
  576                                 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
  577                                                      r_link);
  578                                 TAILQ_INSERT_AFTER(&rm->rm_list, rv, r,
  579                                                      r_link);
  580                         } else if (s->r_start == rv->r_start) {
  581                                 DPRINTF(("allocating from the beginning\n"));
  582                                 /*
  583                                  * We are allocating at the beginning.
  584                                  */
  585                                 s->r_start = rv->r_end + 1;
  586                                 TAILQ_INSERT_BEFORE(s, rv, r_link);
  587                         } else {
  588                                 DPRINTF(("allocating at the end\n"));
  589                                 /*
  590                                  * We are allocating at the end.
  591                                  */
  592                                 s->r_end = rv->r_start - 1;
  593                                 TAILQ_INSERT_AFTER(&rm->rm_list, s, rv,
  594                                                      r_link);
  595                         }
  596                         goto out;
  597                 }
  598         }
  599 
  600         /*
  601          * Now find an acceptable shared region, if the client's requirements
  602          * allow sharing.  By our implementation restriction, a candidate
  603          * region must match exactly by both size and sharing type in order
  604          * to be considered compatible with the client's request.  (The
  605          * former restriction could probably be lifted without too much
  606          * additional work, but this does not seem warranted.)
  607          */
  608         DPRINTF(("no unshared regions found\n"));
  609         if ((flags & RF_SHAREABLE) == 0)
  610                 goto out;
  611 
  612         for (s = r; s && s->r_end <= end; s = TAILQ_NEXT(s, r_link)) {
  613                 if (SHARE_TYPE(s->r_flags) == SHARE_TYPE(flags) &&
  614                     s->r_start >= start &&
  615                     (s->r_end - s->r_start + 1) == count &&
  616                     (s->r_start & amask) == 0 &&
  617                     ((s->r_start ^ s->r_end) & bmask) == 0) {
  618                         rv = int_alloc_resource(M_NOWAIT);
  619                         if (rv == NULL)
  620                                 goto out;
  621                         rv->r_start = s->r_start;
  622                         rv->r_end = s->r_end;
  623                         rv->r_flags = new_rflags;
  624                         rv->r_dev = dev;
  625                         rv->r_rm = rm;
  626                         if (s->r_sharehead == NULL) {
  627                                 s->r_sharehead = malloc(sizeof *s->r_sharehead,
  628                                                 M_RMAN, M_NOWAIT | M_ZERO);
  629                                 if (s->r_sharehead == NULL) {
  630                                         free(rv, M_RMAN);
  631                                         rv = NULL;
  632                                         goto out;
  633                                 }
  634                                 LIST_INIT(s->r_sharehead);
  635                                 LIST_INSERT_HEAD(s->r_sharehead, s,
  636                                                  r_sharelink);
  637                                 s->r_flags |= RF_FIRSTSHARE;
  638                         }
  639                         rv->r_sharehead = s->r_sharehead;
  640                         LIST_INSERT_HEAD(s->r_sharehead, rv, r_sharelink);
  641                         goto out;
  642                 }
  643         }
  644         /*
  645          * We couldn't find anything.
  646          */
  647 
  648 out:
  649         mtx_unlock(rm->rm_mtx);
  650         return (rv == NULL ? NULL : &rv->r_r);
  651 }
  652 
  653 struct resource *
  654 rman_reserve_resource(struct rman *rm, rman_res_t start, rman_res_t end,
  655                       rman_res_t count, u_int flags, device_t dev)
  656 {
  657 
  658         return (rman_reserve_resource_bound(rm, start, end, count, 0, flags,
  659             dev));
  660 }
  661 
  662 int
  663 rman_activate_resource(struct resource *re)
  664 {
  665         struct resource_i *r;
  666         struct rman *rm;
  667 
  668         r = re->__r_i;
  669         rm = r->r_rm;
  670         mtx_lock(rm->rm_mtx);
  671         r->r_flags |= RF_ACTIVE;
  672         mtx_unlock(rm->rm_mtx);
  673         return 0;
  674 }
  675 
  676 int
  677 rman_deactivate_resource(struct resource *r)
  678 {
  679         struct rman *rm;
  680 
  681         rm = r->__r_i->r_rm;
  682         mtx_lock(rm->rm_mtx);
  683         r->__r_i->r_flags &= ~RF_ACTIVE;
  684         mtx_unlock(rm->rm_mtx);
  685         return 0;
  686 }
  687 
  688 static int
  689 int_rman_release_resource(struct rman *rm, struct resource_i *r)
  690 {
  691         struct resource_i *s, *t;
  692 
  693         if (r->r_flags & RF_ACTIVE)
  694                 r->r_flags &= ~RF_ACTIVE;
  695 
  696         /*
  697          * Check for a sharing list first.  If there is one, then we don't
  698          * have to think as hard.
  699          */
  700         if (r->r_sharehead) {
  701                 /*
  702                  * If a sharing list exists, then we know there are at
  703                  * least two sharers.
  704                  *
  705                  * If we are in the main circleq, appoint someone else.
  706                  */
  707                 LIST_REMOVE(r, r_sharelink);
  708                 s = LIST_FIRST(r->r_sharehead);
  709                 if (r->r_flags & RF_FIRSTSHARE) {
  710                         s->r_flags |= RF_FIRSTSHARE;
  711                         TAILQ_INSERT_BEFORE(r, s, r_link);
  712                         TAILQ_REMOVE(&rm->rm_list, r, r_link);
  713                 }
  714 
  715                 /*
  716                  * Make sure that the sharing list goes away completely
  717                  * if the resource is no longer being shared at all.
  718                  */
  719                 if (LIST_NEXT(s, r_sharelink) == NULL) {
  720                         free(s->r_sharehead, M_RMAN);
  721                         s->r_sharehead = NULL;
  722                         s->r_flags &= ~RF_FIRSTSHARE;
  723                 }
  724                 goto out;
  725         }
  726 
  727         /*
  728          * Look at the adjacent resources in the list and see if our
  729          * segment can be merged with any of them.  If either of the
  730          * resources is allocated or is not exactly adjacent then they
  731          * cannot be merged with our segment.
  732          */
  733         s = TAILQ_PREV(r, resource_head, r_link);
  734         if (s != NULL && ((s->r_flags & RF_ALLOCATED) != 0 ||
  735             s->r_end + 1 != r->r_start))
  736                 s = NULL;
  737         t = TAILQ_NEXT(r, r_link);
  738         if (t != NULL && ((t->r_flags & RF_ALLOCATED) != 0 ||
  739             r->r_end + 1 != t->r_start))
  740                 t = NULL;
  741 
  742         if (s != NULL && t != NULL) {
  743                 /*
  744                  * Merge all three segments.
  745                  */
  746                 s->r_end = t->r_end;
  747                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  748                 TAILQ_REMOVE(&rm->rm_list, t, r_link);
  749                 free(t, M_RMAN);
  750         } else if (s != NULL) {
  751                 /*
  752                  * Merge previous segment with ours.
  753                  */
  754                 s->r_end = r->r_end;
  755                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  756         } else if (t != NULL) {
  757                 /*
  758                  * Merge next segment with ours.
  759                  */
  760                 t->r_start = r->r_start;
  761                 TAILQ_REMOVE(&rm->rm_list, r, r_link);
  762         } else {
  763                 /*
  764                  * At this point, we know there is nothing we
  765                  * can potentially merge with, because on each
  766                  * side, there is either nothing there or what is
  767                  * there is still allocated.  In that case, we don't
  768                  * want to remove r from the list; we simply want to
  769                  * change it to an unallocated region and return
  770                  * without freeing anything.
  771                  */
  772                 r->r_flags &= ~RF_ALLOCATED;
  773                 r->r_dev = NULL;
  774                 return 0;
  775         }
  776 
  777 out:
  778         free(r, M_RMAN);
  779         return 0;
  780 }
  781 
  782 int
  783 rman_release_resource(struct resource *re)
  784 {
  785         int rv;
  786         struct resource_i *r;
  787         struct rman *rm;
  788 
  789         r = re->__r_i;
  790         rm = r->r_rm;
  791         mtx_lock(rm->rm_mtx);
  792         rv = int_rman_release_resource(rm, r);
  793         mtx_unlock(rm->rm_mtx);
  794         return (rv);
  795 }
  796 
  797 uint32_t
  798 rman_make_alignment_flags(uint32_t size)
  799 {
  800         int i;
  801 
  802         /*
  803          * Find the hightest bit set, and add one if more than one bit
  804          * set.  We're effectively computing the ceil(log2(size)) here.
  805          */
  806         for (i = 31; i > 0; i--)
  807                 if ((1 << i) & size)
  808                         break;
  809         if (~(1 << i) & size)
  810                 i++;
  811 
  812         return(RF_ALIGNMENT_LOG2(i));
  813 }
  814 
  815 void
  816 rman_set_start(struct resource *r, rman_res_t start)
  817 {
  818 
  819         r->__r_i->r_start = start;
  820 }
  821 
  822 rman_res_t
  823 rman_get_start(struct resource *r)
  824 {
  825 
  826         return (r->__r_i->r_start);
  827 }
  828 
  829 void
  830 rman_set_end(struct resource *r, rman_res_t end)
  831 {
  832 
  833         r->__r_i->r_end = end;
  834 }
  835 
  836 rman_res_t
  837 rman_get_end(struct resource *r)
  838 {
  839 
  840         return (r->__r_i->r_end);
  841 }
  842 
  843 rman_res_t
  844 rman_get_size(struct resource *r)
  845 {
  846 
  847         return (r->__r_i->r_end - r->__r_i->r_start + 1);
  848 }
  849 
  850 u_int
  851 rman_get_flags(struct resource *r)
  852 {
  853 
  854         return (r->__r_i->r_flags);
  855 }
  856 
  857 void
  858 rman_set_virtual(struct resource *r, void *v)
  859 {
  860 
  861         r->__r_i->r_virtual = v;
  862 }
  863 
  864 void *
  865 rman_get_virtual(struct resource *r)
  866 {
  867 
  868         return (r->__r_i->r_virtual);
  869 }
  870 
  871 void
  872 rman_set_bustag(struct resource *r, bus_space_tag_t t)
  873 {
  874 
  875         r->r_bustag = t;
  876 }
  877 
  878 bus_space_tag_t
  879 rman_get_bustag(struct resource *r)
  880 {
  881 
  882         return (r->r_bustag);
  883 }
  884 
  885 void
  886 rman_set_bushandle(struct resource *r, bus_space_handle_t h)
  887 {
  888 
  889         r->r_bushandle = h;
  890 }
  891 
  892 bus_space_handle_t
  893 rman_get_bushandle(struct resource *r)
  894 {
  895 
  896         return (r->r_bushandle);
  897 }
  898 
  899 void
  900 rman_set_mapping(struct resource *r, struct resource_map *map)
  901 {
  902 
  903         KASSERT(rman_get_size(r) == map->r_size,
  904             ("rman_set_mapping: size mismatch"));
  905         rman_set_bustag(r, map->r_bustag);
  906         rman_set_bushandle(r, map->r_bushandle);
  907         rman_set_virtual(r, map->r_vaddr);
  908 }
  909 
  910 void
  911 rman_get_mapping(struct resource *r, struct resource_map *map)
  912 {
  913 
  914         map->r_bustag = rman_get_bustag(r);
  915         map->r_bushandle = rman_get_bushandle(r);
  916         map->r_size = rman_get_size(r);
  917         map->r_vaddr = rman_get_virtual(r);
  918 }
  919 
  920 void
  921 rman_set_rid(struct resource *r, int rid)
  922 {
  923 
  924         r->__r_i->r_rid = rid;
  925 }
  926 
  927 int
  928 rman_get_rid(struct resource *r)
  929 {
  930 
  931         return (r->__r_i->r_rid);
  932 }
  933 
  934 void
  935 rman_set_device(struct resource *r, device_t dev)
  936 {
  937 
  938         r->__r_i->r_dev = dev;
  939 }
  940 
  941 device_t
  942 rman_get_device(struct resource *r)
  943 {
  944 
  945         return (r->__r_i->r_dev);
  946 }
  947 
  948 int
  949 rman_is_region_manager(struct resource *r, struct rman *rm)
  950 {
  951 
  952         return (r->__r_i->r_rm == rm);
  953 }
  954 
  955 /*
  956  * Sysctl interface for scanning the resource lists.
  957  *
  958  * We take two input parameters; the index into the list of resource
  959  * managers, and the resource offset into the list.
  960  */
  961 static int
  962 sysctl_rman(SYSCTL_HANDLER_ARGS)
  963 {
  964         int                     *name = (int *)arg1;
  965         u_int                   namelen = arg2;
  966         int                     rman_idx, res_idx;
  967         struct rman             *rm;
  968         struct resource_i       *res;
  969         struct resource_i       *sres;
  970         struct u_rman           urm;
  971         struct u_resource       ures;
  972         int                     error;
  973 
  974         if (namelen != 3)
  975                 return (EINVAL);
  976 
  977         if (bus_data_generation_check(name[0]))
  978                 return (EINVAL);
  979         rman_idx = name[1];
  980         res_idx = name[2];
  981 
  982         /*
  983          * Find the indexed resource manager
  984          */
  985         mtx_lock(&rman_mtx);
  986         TAILQ_FOREACH(rm, &rman_head, rm_link) {
  987                 if (rman_idx-- == 0)
  988                         break;
  989         }
  990         mtx_unlock(&rman_mtx);
  991         if (rm == NULL)
  992                 return (ENOENT);
  993 
  994         /*
  995          * If the resource index is -1, we want details on the
  996          * resource manager.
  997          */
  998         if (res_idx == -1) {
  999                 bzero(&urm, sizeof(urm));
 1000                 urm.rm_handle = (uintptr_t)rm;
 1001                 if (rm->rm_descr != NULL)
 1002                         strlcpy(urm.rm_descr, rm->rm_descr, RM_TEXTLEN);
 1003                 urm.rm_start = rm->rm_start;
 1004                 urm.rm_size = rm->rm_end - rm->rm_start + 1;
 1005                 urm.rm_type = rm->rm_type;
 1006 
 1007                 error = SYSCTL_OUT(req, &urm, sizeof(urm));
 1008                 return (error);
 1009         }
 1010 
 1011         /*
 1012          * Find the indexed resource and return it.
 1013          */
 1014         mtx_lock(rm->rm_mtx);
 1015         TAILQ_FOREACH(res, &rm->rm_list, r_link) {
 1016                 if (res->r_sharehead != NULL) {
 1017                         LIST_FOREACH(sres, res->r_sharehead, r_sharelink)
 1018                                 if (res_idx-- == 0) {
 1019                                         res = sres;
 1020                                         goto found;
 1021                                 }
 1022                 }
 1023                 else if (res_idx-- == 0)
 1024                                 goto found;
 1025         }
 1026         mtx_unlock(rm->rm_mtx);
 1027         return (ENOENT);
 1028 
 1029 found:
 1030         bzero(&ures, sizeof(ures));
 1031         ures.r_handle = (uintptr_t)res;
 1032         ures.r_parent = (uintptr_t)res->r_rm;
 1033         ures.r_device = (uintptr_t)res->r_dev;
 1034         if (res->r_dev != NULL) {
 1035                 if (device_get_name(res->r_dev) != NULL) {
 1036                         snprintf(ures.r_devname, RM_TEXTLEN,
 1037                             "%s%d",
 1038                             device_get_name(res->r_dev),
 1039                             device_get_unit(res->r_dev));
 1040                 } else {
 1041                         strlcpy(ures.r_devname, "nomatch",
 1042                             RM_TEXTLEN);
 1043                 }
 1044         } else {
 1045                 ures.r_devname[0] = '\0';
 1046         }
 1047         ures.r_start = res->r_start;
 1048         ures.r_size = res->r_end - res->r_start + 1;
 1049         ures.r_flags = res->r_flags;
 1050 
 1051         mtx_unlock(rm->rm_mtx);
 1052         error = SYSCTL_OUT(req, &ures, sizeof(ures));
 1053         return (error);
 1054 }
 1055 
 1056 static SYSCTL_NODE(_hw_bus, OID_AUTO, rman, CTLFLAG_RD, sysctl_rman,
 1057     "kernel resource manager");
 1058 
 1059 #ifdef DDB
 1060 static void
 1061 dump_rman_header(struct rman *rm)
 1062 {
 1063 
 1064         if (db_pager_quit)
 1065                 return;
 1066         db_printf("rman %p: %s (0x%jx-0x%jx full range)\n",
 1067             rm, rm->rm_descr, (rman_res_t)rm->rm_start, (rman_res_t)rm->rm_end);
 1068 }
 1069 
 1070 static void
 1071 dump_rman(struct rman *rm)
 1072 {
 1073         struct resource_i *r;
 1074         const char *devname;
 1075 
 1076         if (db_pager_quit)
 1077                 return;
 1078         TAILQ_FOREACH(r, &rm->rm_list, r_link) {
 1079                 if (r->r_dev != NULL) {
 1080                         devname = device_get_nameunit(r->r_dev);
 1081                         if (devname == NULL)
 1082                                 devname = "nomatch";
 1083                 } else
 1084                         devname = NULL;
 1085                 db_printf("    0x%jx-0x%jx (RID=%d) ",
 1086                     r->r_start, r->r_end, r->r_rid);
 1087                 if (devname != NULL)
 1088                         db_printf("(%s)\n", devname);
 1089                 else
 1090                         db_printf("----\n");
 1091                 if (db_pager_quit)
 1092                         return;
 1093         }
 1094 }
 1095 
 1096 DB_SHOW_COMMAND(rman, db_show_rman)
 1097 {
 1098 
 1099         if (have_addr) {
 1100                 dump_rman_header((struct rman *)addr);
 1101                 dump_rman((struct rman *)addr);
 1102         }
 1103 }
 1104 
 1105 DB_SHOW_COMMAND(rmans, db_show_rmans)
 1106 {
 1107         struct rman *rm;
 1108 
 1109         TAILQ_FOREACH(rm, &rman_head, rm_link) {
 1110                 dump_rman_header(rm);
 1111         }
 1112 }
 1113 
 1114 DB_SHOW_ALL_COMMAND(rman, db_show_all_rman)
 1115 {
 1116         struct rman *rm;
 1117 
 1118         TAILQ_FOREACH(rm, &rman_head, rm_link) {
 1119                 dump_rman_header(rm);
 1120                 dump_rman(rm);
 1121         }
 1122 }
 1123 DB_SHOW_ALIAS(allrman, db_show_all_rman);
 1124 #endif

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