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

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    1 /*
    2  *      linux/kernel/resource.c
    3  *
    4  * Copyright (C) 1999   Linus Torvalds
    5  * Copyright (C) 1999   Martin Mares <mj@ucw.cz>
    6  *
    7  * Arbitrary resource management.
    8  */
    9 
   10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   11 
   12 #include <linux/export.h>
   13 #include <linux/errno.h>
   14 #include <linux/ioport.h>
   15 #include <linux/init.h>
   16 #include <linux/slab.h>
   17 #include <linux/spinlock.h>
   18 #include <linux/fs.h>
   19 #include <linux/proc_fs.h>
   20 #include <linux/sched.h>
   21 #include <linux/seq_file.h>
   22 #include <linux/device.h>
   23 #include <linux/pfn.h>
   24 #include <asm/io.h>
   25 
   26 
   27 struct resource ioport_resource = {
   28         .name   = "PCI IO",
   29         .start  = 0,
   30         .end    = IO_SPACE_LIMIT,
   31         .flags  = IORESOURCE_IO,
   32 };
   33 EXPORT_SYMBOL(ioport_resource);
   34 
   35 struct resource iomem_resource = {
   36         .name   = "PCI mem",
   37         .start  = 0,
   38         .end    = -1,
   39         .flags  = IORESOURCE_MEM,
   40 };
   41 EXPORT_SYMBOL(iomem_resource);
   42 
   43 /* constraints to be met while allocating resources */
   44 struct resource_constraint {
   45         resource_size_t min, max, align;
   46         resource_size_t (*alignf)(void *, const struct resource *,
   47                         resource_size_t, resource_size_t);
   48         void *alignf_data;
   49 };
   50 
   51 static DEFINE_RWLOCK(resource_lock);
   52 
   53 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
   54 {
   55         struct resource *p = v;
   56         (*pos)++;
   57         if (p->child)
   58                 return p->child;
   59         while (!p->sibling && p->parent)
   60                 p = p->parent;
   61         return p->sibling;
   62 }
   63 
   64 #ifdef CONFIG_PROC_FS
   65 
   66 enum { MAX_IORES_LEVEL = 5 };
   67 
   68 static void *r_start(struct seq_file *m, loff_t *pos)
   69         __acquires(resource_lock)
   70 {
   71         struct resource *p = m->private;
   72         loff_t l = 0;
   73         read_lock(&resource_lock);
   74         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
   75                 ;
   76         return p;
   77 }
   78 
   79 static void r_stop(struct seq_file *m, void *v)
   80         __releases(resource_lock)
   81 {
   82         read_unlock(&resource_lock);
   83 }
   84 
   85 static int r_show(struct seq_file *m, void *v)
   86 {
   87         struct resource *root = m->private;
   88         struct resource *r = v, *p;
   89         int width = root->end < 0x10000 ? 4 : 8;
   90         int depth;
   91 
   92         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
   93                 if (p->parent == root)
   94                         break;
   95         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
   96                         depth * 2, "",
   97                         width, (unsigned long long) r->start,
   98                         width, (unsigned long long) r->end,
   99                         r->name ? r->name : "<BAD>");
  100         return 0;
  101 }
  102 
  103 static const struct seq_operations resource_op = {
  104         .start  = r_start,
  105         .next   = r_next,
  106         .stop   = r_stop,
  107         .show   = r_show,
  108 };
  109 
  110 static int ioports_open(struct inode *inode, struct file *file)
  111 {
  112         int res = seq_open(file, &resource_op);
  113         if (!res) {
  114                 struct seq_file *m = file->private_data;
  115                 m->private = &ioport_resource;
  116         }
  117         return res;
  118 }
  119 
  120 static int iomem_open(struct inode *inode, struct file *file)
  121 {
  122         int res = seq_open(file, &resource_op);
  123         if (!res) {
  124                 struct seq_file *m = file->private_data;
  125                 m->private = &iomem_resource;
  126         }
  127         return res;
  128 }
  129 
  130 static const struct file_operations proc_ioports_operations = {
  131         .open           = ioports_open,
  132         .read           = seq_read,
  133         .llseek         = seq_lseek,
  134         .release        = seq_release,
  135 };
  136 
  137 static const struct file_operations proc_iomem_operations = {
  138         .open           = iomem_open,
  139         .read           = seq_read,
  140         .llseek         = seq_lseek,
  141         .release        = seq_release,
  142 };
  143 
  144 static int __init ioresources_init(void)
  145 {
  146         proc_create("ioports", 0, NULL, &proc_ioports_operations);
  147         proc_create("iomem", 0, NULL, &proc_iomem_operations);
  148         return 0;
  149 }
  150 __initcall(ioresources_init);
  151 
  152 #endif /* CONFIG_PROC_FS */
  153 
  154 /* Return the conflict entry if you can't request it */
  155 static struct resource * __request_resource(struct resource *root, struct resource *new)
  156 {
  157         resource_size_t start = new->start;
  158         resource_size_t end = new->end;
  159         struct resource *tmp, **p;
  160 
  161         if (end < start)
  162                 return root;
  163         if (start < root->start)
  164                 return root;
  165         if (end > root->end)
  166                 return root;
  167         p = &root->child;
  168         for (;;) {
  169                 tmp = *p;
  170                 if (!tmp || tmp->start > end) {
  171                         new->sibling = tmp;
  172                         *p = new;
  173                         new->parent = root;
  174                         return NULL;
  175                 }
  176                 p = &tmp->sibling;
  177                 if (tmp->end < start)
  178                         continue;
  179                 return tmp;
  180         }
  181 }
  182 
  183 static int __release_resource(struct resource *old)
  184 {
  185         struct resource *tmp, **p;
  186 
  187         p = &old->parent->child;
  188         for (;;) {
  189                 tmp = *p;
  190                 if (!tmp)
  191                         break;
  192                 if (tmp == old) {
  193                         *p = tmp->sibling;
  194                         old->parent = NULL;
  195                         return 0;
  196                 }
  197                 p = &tmp->sibling;
  198         }
  199         return -EINVAL;
  200 }
  201 
  202 static void __release_child_resources(struct resource *r)
  203 {
  204         struct resource *tmp, *p;
  205         resource_size_t size;
  206 
  207         p = r->child;
  208         r->child = NULL;
  209         while (p) {
  210                 tmp = p;
  211                 p = p->sibling;
  212 
  213                 tmp->parent = NULL;
  214                 tmp->sibling = NULL;
  215                 __release_child_resources(tmp);
  216 
  217                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
  218                 /* need to restore size, and keep flags */
  219                 size = resource_size(tmp);
  220                 tmp->start = 0;
  221                 tmp->end = size - 1;
  222         }
  223 }
  224 
  225 void release_child_resources(struct resource *r)
  226 {
  227         write_lock(&resource_lock);
  228         __release_child_resources(r);
  229         write_unlock(&resource_lock);
  230 }
  231 
  232 /**
  233  * request_resource_conflict - request and reserve an I/O or memory resource
  234  * @root: root resource descriptor
  235  * @new: resource descriptor desired by caller
  236  *
  237  * Returns 0 for success, conflict resource on error.
  238  */
  239 struct resource *request_resource_conflict(struct resource *root, struct resource *new)
  240 {
  241         struct resource *conflict;
  242 
  243         write_lock(&resource_lock);
  244         conflict = __request_resource(root, new);
  245         write_unlock(&resource_lock);
  246         return conflict;
  247 }
  248 
  249 /**
  250  * request_resource - request and reserve an I/O or memory resource
  251  * @root: root resource descriptor
  252  * @new: resource descriptor desired by caller
  253  *
  254  * Returns 0 for success, negative error code on error.
  255  */
  256 int request_resource(struct resource *root, struct resource *new)
  257 {
  258         struct resource *conflict;
  259 
  260         conflict = request_resource_conflict(root, new);
  261         return conflict ? -EBUSY : 0;
  262 }
  263 
  264 EXPORT_SYMBOL(request_resource);
  265 
  266 /**
  267  * release_resource - release a previously reserved resource
  268  * @old: resource pointer
  269  */
  270 int release_resource(struct resource *old)
  271 {
  272         int retval;
  273 
  274         write_lock(&resource_lock);
  275         retval = __release_resource(old);
  276         write_unlock(&resource_lock);
  277         return retval;
  278 }
  279 
  280 EXPORT_SYMBOL(release_resource);
  281 
  282 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
  283 /*
  284  * Finds the lowest memory reosurce exists within [res->start.res->end)
  285  * the caller must specify res->start, res->end, res->flags and "name".
  286  * If found, returns 0, res is overwritten, if not found, returns -1.
  287  */
  288 static int find_next_system_ram(struct resource *res, char *name)
  289 {
  290         resource_size_t start, end;
  291         struct resource *p;
  292 
  293         BUG_ON(!res);
  294 
  295         start = res->start;
  296         end = res->end;
  297         BUG_ON(start >= end);
  298 
  299         read_lock(&resource_lock);
  300         for (p = iomem_resource.child; p ; p = p->sibling) {
  301                 /* system ram is just marked as IORESOURCE_MEM */
  302                 if (p->flags != res->flags)
  303                         continue;
  304                 if (name && strcmp(p->name, name))
  305                         continue;
  306                 if (p->start > end) {
  307                         p = NULL;
  308                         break;
  309                 }
  310                 if ((p->end >= start) && (p->start < end))
  311                         break;
  312         }
  313         read_unlock(&resource_lock);
  314         if (!p)
  315                 return -1;
  316         /* copy data */
  317         if (res->start < p->start)
  318                 res->start = p->start;
  319         if (res->end > p->end)
  320                 res->end = p->end;
  321         return 0;
  322 }
  323 
  324 /*
  325  * This function calls callback against all memory range of "System RAM"
  326  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
  327  * Now, this function is only for "System RAM".
  328  */
  329 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
  330                 void *arg, int (*func)(unsigned long, unsigned long, void *))
  331 {
  332         struct resource res;
  333         unsigned long pfn, end_pfn;
  334         u64 orig_end;
  335         int ret = -1;
  336 
  337         res.start = (u64) start_pfn << PAGE_SHIFT;
  338         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
  339         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
  340         orig_end = res.end;
  341         while ((res.start < res.end) &&
  342                 (find_next_system_ram(&res, "System RAM") >= 0)) {
  343                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
  344                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
  345                 if (end_pfn > pfn)
  346                         ret = (*func)(pfn, end_pfn - pfn, arg);
  347                 if (ret)
  348                         break;
  349                 res.start = res.end + 1;
  350                 res.end = orig_end;
  351         }
  352         return ret;
  353 }
  354 
  355 #endif
  356 
  357 static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
  358 {
  359         return 1;
  360 }
  361 /*
  362  * This generic page_is_ram() returns true if specified address is
  363  * registered as "System RAM" in iomem_resource list.
  364  */
  365 int __weak page_is_ram(unsigned long pfn)
  366 {
  367         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
  368 }
  369 
  370 void __weak arch_remove_reservations(struct resource *avail)
  371 {
  372 }
  373 
  374 static resource_size_t simple_align_resource(void *data,
  375                                              const struct resource *avail,
  376                                              resource_size_t size,
  377                                              resource_size_t align)
  378 {
  379         return avail->start;
  380 }
  381 
  382 static void resource_clip(struct resource *res, resource_size_t min,
  383                           resource_size_t max)
  384 {
  385         if (res->start < min)
  386                 res->start = min;
  387         if (res->end > max)
  388                 res->end = max;
  389 }
  390 
  391 static bool resource_contains(struct resource *res1, struct resource *res2)
  392 {
  393         return res1->start <= res2->start && res1->end >= res2->end;
  394 }
  395 
  396 /*
  397  * Find empty slot in the resource tree with the given range and
  398  * alignment constraints
  399  */
  400 static int __find_resource(struct resource *root, struct resource *old,
  401                          struct resource *new,
  402                          resource_size_t  size,
  403                          struct resource_constraint *constraint)
  404 {
  405         struct resource *this = root->child;
  406         struct resource tmp = *new, avail, alloc;
  407 
  408         tmp.flags = new->flags;
  409         tmp.start = root->start;
  410         /*
  411          * Skip past an allocated resource that starts at 0, since the assignment
  412          * of this->start - 1 to tmp->end below would cause an underflow.
  413          */
  414         if (this && this->start == root->start) {
  415                 tmp.start = (this == old) ? old->start : this->end + 1;
  416                 this = this->sibling;
  417         }
  418         for(;;) {
  419                 if (this)
  420                         tmp.end = (this == old) ?  this->end : this->start - 1;
  421                 else
  422                         tmp.end = root->end;
  423 
  424                 if (tmp.end < tmp.start)
  425                         goto next;
  426 
  427                 resource_clip(&tmp, constraint->min, constraint->max);
  428                 arch_remove_reservations(&tmp);
  429 
  430                 /* Check for overflow after ALIGN() */
  431                 avail = *new;
  432                 avail.start = ALIGN(tmp.start, constraint->align);
  433                 avail.end = tmp.end;
  434                 if (avail.start >= tmp.start) {
  435                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
  436                                         size, constraint->align);
  437                         alloc.end = alloc.start + size - 1;
  438                         if (resource_contains(&avail, &alloc)) {
  439                                 new->start = alloc.start;
  440                                 new->end = alloc.end;
  441                                 return 0;
  442                         }
  443                 }
  444 
  445 next:           if (!this || this->end == root->end)
  446                         break;
  447 
  448                 if (this != old)
  449                         tmp.start = this->end + 1;
  450                 this = this->sibling;
  451         }
  452         return -EBUSY;
  453 }
  454 
  455 /*
  456  * Find empty slot in the resource tree given range and alignment.
  457  */
  458 static int find_resource(struct resource *root, struct resource *new,
  459                         resource_size_t size,
  460                         struct resource_constraint  *constraint)
  461 {
  462         return  __find_resource(root, NULL, new, size, constraint);
  463 }
  464 
  465 /**
  466  * reallocate_resource - allocate a slot in the resource tree given range & alignment.
  467  *      The resource will be relocated if the new size cannot be reallocated in the
  468  *      current location.
  469  *
  470  * @root: root resource descriptor
  471  * @old:  resource descriptor desired by caller
  472  * @newsize: new size of the resource descriptor
  473  * @constraint: the size and alignment constraints to be met.
  474  */
  475 int reallocate_resource(struct resource *root, struct resource *old,
  476                         resource_size_t newsize,
  477                         struct resource_constraint  *constraint)
  478 {
  479         int err=0;
  480         struct resource new = *old;
  481         struct resource *conflict;
  482 
  483         write_lock(&resource_lock);
  484 
  485         if ((err = __find_resource(root, old, &new, newsize, constraint)))
  486                 goto out;
  487 
  488         if (resource_contains(&new, old)) {
  489                 old->start = new.start;
  490                 old->end = new.end;
  491                 goto out;
  492         }
  493 
  494         if (old->child) {
  495                 err = -EBUSY;
  496                 goto out;
  497         }
  498 
  499         if (resource_contains(old, &new)) {
  500                 old->start = new.start;
  501                 old->end = new.end;
  502         } else {
  503                 __release_resource(old);
  504                 *old = new;
  505                 conflict = __request_resource(root, old);
  506                 BUG_ON(conflict);
  507         }
  508 out:
  509         write_unlock(&resource_lock);
  510         return err;
  511 }
  512 
  513 
  514 /**
  515  * allocate_resource - allocate empty slot in the resource tree given range & alignment.
  516  *      The resource will be reallocated with a new size if it was already allocated
  517  * @root: root resource descriptor
  518  * @new: resource descriptor desired by caller
  519  * @size: requested resource region size
  520  * @min: minimum boundary to allocate
  521  * @max: maximum boundary to allocate
  522  * @align: alignment requested, in bytes
  523  * @alignf: alignment function, optional, called if not NULL
  524  * @alignf_data: arbitrary data to pass to the @alignf function
  525  */
  526 int allocate_resource(struct resource *root, struct resource *new,
  527                       resource_size_t size, resource_size_t min,
  528                       resource_size_t max, resource_size_t align,
  529                       resource_size_t (*alignf)(void *,
  530                                                 const struct resource *,
  531                                                 resource_size_t,
  532                                                 resource_size_t),
  533                       void *alignf_data)
  534 {
  535         int err;
  536         struct resource_constraint constraint;
  537 
  538         if (!alignf)
  539                 alignf = simple_align_resource;
  540 
  541         constraint.min = min;
  542         constraint.max = max;
  543         constraint.align = align;
  544         constraint.alignf = alignf;
  545         constraint.alignf_data = alignf_data;
  546 
  547         if ( new->parent ) {
  548                 /* resource is already allocated, try reallocating with
  549                    the new constraints */
  550                 return reallocate_resource(root, new, size, &constraint);
  551         }
  552 
  553         write_lock(&resource_lock);
  554         err = find_resource(root, new, size, &constraint);
  555         if (err >= 0 && __request_resource(root, new))
  556                 err = -EBUSY;
  557         write_unlock(&resource_lock);
  558         return err;
  559 }
  560 
  561 EXPORT_SYMBOL(allocate_resource);
  562 
  563 /**
  564  * lookup_resource - find an existing resource by a resource start address
  565  * @root: root resource descriptor
  566  * @start: resource start address
  567  *
  568  * Returns a pointer to the resource if found, NULL otherwise
  569  */
  570 struct resource *lookup_resource(struct resource *root, resource_size_t start)
  571 {
  572         struct resource *res;
  573 
  574         read_lock(&resource_lock);
  575         for (res = root->child; res; res = res->sibling) {
  576                 if (res->start == start)
  577                         break;
  578         }
  579         read_unlock(&resource_lock);
  580 
  581         return res;
  582 }
  583 
  584 /*
  585  * Insert a resource into the resource tree. If successful, return NULL,
  586  * otherwise return the conflicting resource (compare to __request_resource())
  587  */
  588 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
  589 {
  590         struct resource *first, *next;
  591 
  592         for (;; parent = first) {
  593                 first = __request_resource(parent, new);
  594                 if (!first)
  595                         return first;
  596 
  597                 if (first == parent)
  598                         return first;
  599                 if (WARN_ON(first == new))      /* duplicated insertion */
  600                         return first;
  601 
  602                 if ((first->start > new->start) || (first->end < new->end))
  603                         break;
  604                 if ((first->start == new->start) && (first->end == new->end))
  605                         break;
  606         }
  607 
  608         for (next = first; ; next = next->sibling) {
  609                 /* Partial overlap? Bad, and unfixable */
  610                 if (next->start < new->start || next->end > new->end)
  611                         return next;
  612                 if (!next->sibling)
  613                         break;
  614                 if (next->sibling->start > new->end)
  615                         break;
  616         }
  617 
  618         new->parent = parent;
  619         new->sibling = next->sibling;
  620         new->child = first;
  621 
  622         next->sibling = NULL;
  623         for (next = first; next; next = next->sibling)
  624                 next->parent = new;
  625 
  626         if (parent->child == first) {
  627                 parent->child = new;
  628         } else {
  629                 next = parent->child;
  630                 while (next->sibling != first)
  631                         next = next->sibling;
  632                 next->sibling = new;
  633         }
  634         return NULL;
  635 }
  636 
  637 /**
  638  * insert_resource_conflict - Inserts resource in the resource tree
  639  * @parent: parent of the new resource
  640  * @new: new resource to insert
  641  *
  642  * Returns 0 on success, conflict resource if the resource can't be inserted.
  643  *
  644  * This function is equivalent to request_resource_conflict when no conflict
  645  * happens. If a conflict happens, and the conflicting resources
  646  * entirely fit within the range of the new resource, then the new
  647  * resource is inserted and the conflicting resources become children of
  648  * the new resource.
  649  */
  650 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
  651 {
  652         struct resource *conflict;
  653 
  654         write_lock(&resource_lock);
  655         conflict = __insert_resource(parent, new);
  656         write_unlock(&resource_lock);
  657         return conflict;
  658 }
  659 
  660 /**
  661  * insert_resource - Inserts a resource in the resource tree
  662  * @parent: parent of the new resource
  663  * @new: new resource to insert
  664  *
  665  * Returns 0 on success, -EBUSY if the resource can't be inserted.
  666  */
  667 int insert_resource(struct resource *parent, struct resource *new)
  668 {
  669         struct resource *conflict;
  670 
  671         conflict = insert_resource_conflict(parent, new);
  672         return conflict ? -EBUSY : 0;
  673 }
  674 
  675 /**
  676  * insert_resource_expand_to_fit - Insert a resource into the resource tree
  677  * @root: root resource descriptor
  678  * @new: new resource to insert
  679  *
  680  * Insert a resource into the resource tree, possibly expanding it in order
  681  * to make it encompass any conflicting resources.
  682  */
  683 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
  684 {
  685         if (new->parent)
  686                 return;
  687 
  688         write_lock(&resource_lock);
  689         for (;;) {
  690                 struct resource *conflict;
  691 
  692                 conflict = __insert_resource(root, new);
  693                 if (!conflict)
  694                         break;
  695                 if (conflict == root)
  696                         break;
  697 
  698                 /* Ok, expand resource to cover the conflict, then try again .. */
  699                 if (conflict->start < new->start)
  700                         new->start = conflict->start;
  701                 if (conflict->end > new->end)
  702                         new->end = conflict->end;
  703 
  704                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
  705         }
  706         write_unlock(&resource_lock);
  707 }
  708 
  709 /**
  710  * adjust_resource - modify a resource's start and size
  711  * @res: resource to modify
  712  * @start: new start value
  713  * @size: new size
  714  *
  715  * Given an existing resource, change its start and size to match the
  716  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
  717  * Existing children of the resource are assumed to be immutable.
  718  */
  719 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
  720 {
  721         struct resource *tmp, *parent = res->parent;
  722         resource_size_t end = start + size - 1;
  723         int result = -EBUSY;
  724 
  725         write_lock(&resource_lock);
  726 
  727         if (!parent)
  728                 goto skip;
  729 
  730         if ((start < parent->start) || (end > parent->end))
  731                 goto out;
  732 
  733         if (res->sibling && (res->sibling->start <= end))
  734                 goto out;
  735 
  736         tmp = parent->child;
  737         if (tmp != res) {
  738                 while (tmp->sibling != res)
  739                         tmp = tmp->sibling;
  740                 if (start <= tmp->end)
  741                         goto out;
  742         }
  743 
  744 skip:
  745         for (tmp = res->child; tmp; tmp = tmp->sibling)
  746                 if ((tmp->start < start) || (tmp->end > end))
  747                         goto out;
  748 
  749         res->start = start;
  750         res->end = end;
  751         result = 0;
  752 
  753  out:
  754         write_unlock(&resource_lock);
  755         return result;
  756 }
  757 EXPORT_SYMBOL(adjust_resource);
  758 
  759 static void __init __reserve_region_with_split(struct resource *root,
  760                 resource_size_t start, resource_size_t end,
  761                 const char *name)
  762 {
  763         struct resource *parent = root;
  764         struct resource *conflict;
  765         struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
  766         struct resource *next_res = NULL;
  767 
  768         if (!res)
  769                 return;
  770 
  771         res->name = name;
  772         res->start = start;
  773         res->end = end;
  774         res->flags = IORESOURCE_BUSY;
  775 
  776         while (1) {
  777 
  778                 conflict = __request_resource(parent, res);
  779                 if (!conflict) {
  780                         if (!next_res)
  781                                 break;
  782                         res = next_res;
  783                         next_res = NULL;
  784                         continue;
  785                 }
  786 
  787                 /* conflict covered whole area */
  788                 if (conflict->start <= res->start &&
  789                                 conflict->end >= res->end) {
  790                         kfree(res);
  791                         WARN_ON(next_res);
  792                         break;
  793                 }
  794 
  795                 /* failed, split and try again */
  796                 if (conflict->start > res->start) {
  797                         end = res->end;
  798                         res->end = conflict->start - 1;
  799                         if (conflict->end < end) {
  800                                 next_res = kzalloc(sizeof(*next_res),
  801                                                 GFP_ATOMIC);
  802                                 if (!next_res) {
  803                                         kfree(res);
  804                                         break;
  805                                 }
  806                                 next_res->name = name;
  807                                 next_res->start = conflict->end + 1;
  808                                 next_res->end = end;
  809                                 next_res->flags = IORESOURCE_BUSY;
  810                         }
  811                 } else {
  812                         res->start = conflict->end + 1;
  813                 }
  814         }
  815 
  816 }
  817 
  818 void __init reserve_region_with_split(struct resource *root,
  819                 resource_size_t start, resource_size_t end,
  820                 const char *name)
  821 {
  822         int abort = 0;
  823 
  824         write_lock(&resource_lock);
  825         if (root->start > start || root->end < end) {
  826                 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
  827                        (unsigned long long)start, (unsigned long long)end,
  828                        root);
  829                 if (start > root->end || end < root->start)
  830                         abort = 1;
  831                 else {
  832                         if (end > root->end)
  833                                 end = root->end;
  834                         if (start < root->start)
  835                                 start = root->start;
  836                         pr_err("fixing request to [0x%llx-0x%llx]\n",
  837                                (unsigned long long)start,
  838                                (unsigned long long)end);
  839                 }
  840                 dump_stack();
  841         }
  842         if (!abort)
  843                 __reserve_region_with_split(root, start, end, name);
  844         write_unlock(&resource_lock);
  845 }
  846 
  847 /**
  848  * resource_alignment - calculate resource's alignment
  849  * @res: resource pointer
  850  *
  851  * Returns alignment on success, 0 (invalid alignment) on failure.
  852  */
  853 resource_size_t resource_alignment(struct resource *res)
  854 {
  855         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
  856         case IORESOURCE_SIZEALIGN:
  857                 return resource_size(res);
  858         case IORESOURCE_STARTALIGN:
  859                 return res->start;
  860         default:
  861                 return 0;
  862         }
  863 }
  864 
  865 /*
  866  * This is compatibility stuff for IO resources.
  867  *
  868  * Note how this, unlike the above, knows about
  869  * the IO flag meanings (busy etc).
  870  *
  871  * request_region creates a new busy region.
  872  *
  873  * check_region returns non-zero if the area is already busy.
  874  *
  875  * release_region releases a matching busy region.
  876  */
  877 
  878 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
  879 
  880 /**
  881  * __request_region - create a new busy resource region
  882  * @parent: parent resource descriptor
  883  * @start: resource start address
  884  * @n: resource region size
  885  * @name: reserving caller's ID string
  886  * @flags: IO resource flags
  887  */
  888 struct resource * __request_region(struct resource *parent,
  889                                    resource_size_t start, resource_size_t n,
  890                                    const char *name, int flags)
  891 {
  892         DECLARE_WAITQUEUE(wait, current);
  893         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
  894 
  895         if (!res)
  896                 return NULL;
  897 
  898         res->name = name;
  899         res->start = start;
  900         res->end = start + n - 1;
  901         res->flags = IORESOURCE_BUSY;
  902         res->flags |= flags;
  903 
  904         write_lock(&resource_lock);
  905 
  906         for (;;) {
  907                 struct resource *conflict;
  908 
  909                 conflict = __request_resource(parent, res);
  910                 if (!conflict)
  911                         break;
  912                 if (conflict != parent) {
  913                         parent = conflict;
  914                         if (!(conflict->flags & IORESOURCE_BUSY))
  915                                 continue;
  916                 }
  917                 if (conflict->flags & flags & IORESOURCE_MUXED) {
  918                         add_wait_queue(&muxed_resource_wait, &wait);
  919                         write_unlock(&resource_lock);
  920                         set_current_state(TASK_UNINTERRUPTIBLE);
  921                         schedule();
  922                         remove_wait_queue(&muxed_resource_wait, &wait);
  923                         write_lock(&resource_lock);
  924                         continue;
  925                 }
  926                 /* Uhhuh, that didn't work out.. */
  927                 kfree(res);
  928                 res = NULL;
  929                 break;
  930         }
  931         write_unlock(&resource_lock);
  932         return res;
  933 }
  934 EXPORT_SYMBOL(__request_region);
  935 
  936 /**
  937  * __check_region - check if a resource region is busy or free
  938  * @parent: parent resource descriptor
  939  * @start: resource start address
  940  * @n: resource region size
  941  *
  942  * Returns 0 if the region is free at the moment it is checked,
  943  * returns %-EBUSY if the region is busy.
  944  *
  945  * NOTE:
  946  * This function is deprecated because its use is racy.
  947  * Even if it returns 0, a subsequent call to request_region()
  948  * may fail because another driver etc. just allocated the region.
  949  * Do NOT use it.  It will be removed from the kernel.
  950  */
  951 int __check_region(struct resource *parent, resource_size_t start,
  952                         resource_size_t n)
  953 {
  954         struct resource * res;
  955 
  956         res = __request_region(parent, start, n, "check-region", 0);
  957         if (!res)
  958                 return -EBUSY;
  959 
  960         release_resource(res);
  961         kfree(res);
  962         return 0;
  963 }
  964 EXPORT_SYMBOL(__check_region);
  965 
  966 /**
  967  * __release_region - release a previously reserved resource region
  968  * @parent: parent resource descriptor
  969  * @start: resource start address
  970  * @n: resource region size
  971  *
  972  * The described resource region must match a currently busy region.
  973  */
  974 void __release_region(struct resource *parent, resource_size_t start,
  975                         resource_size_t n)
  976 {
  977         struct resource **p;
  978         resource_size_t end;
  979 
  980         p = &parent->child;
  981         end = start + n - 1;
  982 
  983         write_lock(&resource_lock);
  984 
  985         for (;;) {
  986                 struct resource *res = *p;
  987 
  988                 if (!res)
  989                         break;
  990                 if (res->start <= start && res->end >= end) {
  991                         if (!(res->flags & IORESOURCE_BUSY)) {
  992                                 p = &res->child;
  993                                 continue;
  994                         }
  995                         if (res->start != start || res->end != end)
  996                                 break;
  997                         *p = res->sibling;
  998                         write_unlock(&resource_lock);
  999                         if (res->flags & IORESOURCE_MUXED)
 1000                                 wake_up(&muxed_resource_wait);
 1001                         kfree(res);
 1002                         return;
 1003                 }
 1004                 p = &res->sibling;
 1005         }
 1006 
 1007         write_unlock(&resource_lock);
 1008 
 1009         printk(KERN_WARNING "Trying to free nonexistent resource "
 1010                 "<%016llx-%016llx>\n", (unsigned long long)start,
 1011                 (unsigned long long)end);
 1012 }
 1013 EXPORT_SYMBOL(__release_region);
 1014 
 1015 /*
 1016  * Managed region resource
 1017  */
 1018 struct region_devres {
 1019         struct resource *parent;
 1020         resource_size_t start;
 1021         resource_size_t n;
 1022 };
 1023 
 1024 static void devm_region_release(struct device *dev, void *res)
 1025 {
 1026         struct region_devres *this = res;
 1027 
 1028         __release_region(this->parent, this->start, this->n);
 1029 }
 1030 
 1031 static int devm_region_match(struct device *dev, void *res, void *match_data)
 1032 {
 1033         struct region_devres *this = res, *match = match_data;
 1034 
 1035         return this->parent == match->parent &&
 1036                 this->start == match->start && this->n == match->n;
 1037 }
 1038 
 1039 struct resource * __devm_request_region(struct device *dev,
 1040                                 struct resource *parent, resource_size_t start,
 1041                                 resource_size_t n, const char *name)
 1042 {
 1043         struct region_devres *dr = NULL;
 1044         struct resource *res;
 1045 
 1046         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 1047                           GFP_KERNEL);
 1048         if (!dr)
 1049                 return NULL;
 1050 
 1051         dr->parent = parent;
 1052         dr->start = start;
 1053         dr->n = n;
 1054 
 1055         res = __request_region(parent, start, n, name, 0);
 1056         if (res)
 1057                 devres_add(dev, dr);
 1058         else
 1059                 devres_free(dr);
 1060 
 1061         return res;
 1062 }
 1063 EXPORT_SYMBOL(__devm_request_region);
 1064 
 1065 void __devm_release_region(struct device *dev, struct resource *parent,
 1066                            resource_size_t start, resource_size_t n)
 1067 {
 1068         struct region_devres match_data = { parent, start, n };
 1069 
 1070         __release_region(parent, start, n);
 1071         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
 1072                                &match_data));
 1073 }
 1074 EXPORT_SYMBOL(__devm_release_region);
 1075 
 1076 /*
 1077  * Called from init/main.c to reserve IO ports.
 1078  */
 1079 #define MAXRESERVE 4
 1080 static int __init reserve_setup(char *str)
 1081 {
 1082         static int reserved;
 1083         static struct resource reserve[MAXRESERVE];
 1084 
 1085         for (;;) {
 1086                 unsigned int io_start, io_num;
 1087                 int x = reserved;
 1088 
 1089                 if (get_option (&str, &io_start) != 2)
 1090                         break;
 1091                 if (get_option (&str, &io_num)   == 0)
 1092                         break;
 1093                 if (x < MAXRESERVE) {
 1094                         struct resource *res = reserve + x;
 1095                         res->name = "reserved";
 1096                         res->start = io_start;
 1097                         res->end = io_start + io_num - 1;
 1098                         res->flags = IORESOURCE_BUSY;
 1099                         res->child = NULL;
 1100                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 1101                                 reserved = x+1;
 1102                 }
 1103         }
 1104         return 1;
 1105 }
 1106 
 1107 __setup("reserve=", reserve_setup);
 1108 
 1109 /*
 1110  * Check if the requested addr and size spans more than any slot in the
 1111  * iomem resource tree.
 1112  */
 1113 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
 1114 {
 1115         struct resource *p = &iomem_resource;
 1116         int err = 0;
 1117         loff_t l;
 1118 
 1119         read_lock(&resource_lock);
 1120         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 1121                 /*
 1122                  * We can probably skip the resources without
 1123                  * IORESOURCE_IO attribute?
 1124                  */
 1125                 if (p->start >= addr + size)
 1126                         continue;
 1127                 if (p->end < addr)
 1128                         continue;
 1129                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
 1130                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
 1131                         continue;
 1132                 /*
 1133                  * if a resource is "BUSY", it's not a hardware resource
 1134                  * but a driver mapping of such a resource; we don't want
 1135                  * to warn for those; some drivers legitimately map only
 1136                  * partial hardware resources. (example: vesafb)
 1137                  */
 1138                 if (p->flags & IORESOURCE_BUSY)
 1139                         continue;
 1140 
 1141                 printk(KERN_WARNING "resource map sanity check conflict: "
 1142                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
 1143                        (unsigned long long)addr,
 1144                        (unsigned long long)(addr + size - 1),
 1145                        (unsigned long long)p->start,
 1146                        (unsigned long long)p->end,
 1147                        p->name);
 1148                 err = -1;
 1149                 break;
 1150         }
 1151         read_unlock(&resource_lock);
 1152 
 1153         return err;
 1154 }
 1155 
 1156 #ifdef CONFIG_STRICT_DEVMEM
 1157 static int strict_iomem_checks = 1;
 1158 #else
 1159 static int strict_iomem_checks;
 1160 #endif
 1161 
 1162 /*
 1163  * check if an address is reserved in the iomem resource tree
 1164  * returns 1 if reserved, 0 if not reserved.
 1165  */
 1166 int iomem_is_exclusive(u64 addr)
 1167 {
 1168         struct resource *p = &iomem_resource;
 1169         int err = 0;
 1170         loff_t l;
 1171         int size = PAGE_SIZE;
 1172 
 1173         if (!strict_iomem_checks)
 1174                 return 0;
 1175 
 1176         addr = addr & PAGE_MASK;
 1177 
 1178         read_lock(&resource_lock);
 1179         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 1180                 /*
 1181                  * We can probably skip the resources without
 1182                  * IORESOURCE_IO attribute?
 1183                  */
 1184                 if (p->start >= addr + size)
 1185                         break;
 1186                 if (p->end < addr)
 1187                         continue;
 1188                 if (p->flags & IORESOURCE_BUSY &&
 1189                      p->flags & IORESOURCE_EXCLUSIVE) {
 1190                         err = 1;
 1191                         break;
 1192                 }
 1193         }
 1194         read_unlock(&resource_lock);
 1195 
 1196         return err;
 1197 }
 1198 
 1199 static int __init strict_iomem(char *str)
 1200 {
 1201         if (strstr(str, "relaxed"))
 1202                 strict_iomem_checks = 0;
 1203         if (strstr(str, "strict"))
 1204                 strict_iomem_checks = 1;
 1205         return 1;
 1206 }
 1207 
 1208 __setup("iomem=", strict_iomem);

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