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