kernel/resource.c

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