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/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/seq_file.h>
  19 #include <linux/device.h>
  20 #include <linux/pfn.h>
  21 #include <asm/io.h>
  22
  23
  24 struct resource ioport_resource = {
  25         .name   = "PCI IO",
  26         .start  = 0,
  27         .end    = IO_SPACE_LIMIT,
  28         .flags  = IORESOURCE_IO,
  29 };
  30 EXPORT_SYMBOL(ioport_resource);
  31
  32 struct resource iomem_resource = {
  33         .name   = "PCI mem",
  34         .start  = 0,
  35         .end    = -1,
  36         .flags  = IORESOURCE_MEM,
  37 };
  38 EXPORT_SYMBOL(iomem_resource);
  39
  40 static DEFINE_RWLOCK(resource_lock);
  41
  42 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  43 {
  44         struct resource *p = v;
  45         (*pos)++;
  46         if (p->child)
  47                 return p->child;
  48         while (!p->sibling && p->parent)
  49                 p = p->parent;
  50         return p->sibling;
  51 }
  52
  53 #ifdef CONFIG_PROC_FS
  54
  55 enum { MAX_IORES_LEVEL = 5 };
  56
  57 static void *r_start(struct seq_file *m, loff_t *pos)
  58         __acquires(resource_lock)
  59 {
  60         struct resource *p = m->private;
  61         loff_t l = 0;
  62         read_lock(&resource_lock);
  63         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  64                 ;
  65         return p;
  66 }
  67
  68 static void r_stop(struct seq_file *m, void *v)
  69         __releases(resource_lock)
  70 {
  71         read_unlock(&resource_lock);
  72 }
  73
  74 static int r_show(struct seq_file *m, void *v)
  75 {
  76         struct resource *root = m->private;
  77         struct resource *r = v, *p;
  78         int width = root->end < 0x10000 ? 4 : 8;
  79         int depth;
  80
  81         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
  82                 if (p->parent == root)
  83                         break;
  84         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
  85                         depth * 2, "",
  86                         width, (unsigned long long) r->start,
  87                         width, (unsigned long long) r->end,
  88                         r->name ? r->name : "<BAD>");
  89         return 0;
  90 }
  91
  92 static const struct seq_operations resource_op = {
  93         .start  = r_start,
  94         .next   = r_next,
  95         .stop   = r_stop,
  96         .show   = r_show,
  97 };
  98
  99 static int ioports_open(struct inode *inode, struct file *file)
 100 {
 101         int res = seq_open(file, &resource_op);
 102         if (!res) {
 103                 struct seq_file *m = file->private_data;
 104                 m->private = &ioport_resource;
 105         }
 106         return res;
 107 }
 108
 109 static int iomem_open(struct inode *inode, struct file *file)
 110 {
 111         int res = seq_open(file, &resource_op);
 112         if (!res) {
 113                 struct seq_file *m = file->private_data;
 114                 m->private = &iomem_resource;
 115         }
 116         return res;
 117 }
 118
 119 static const struct file_operations proc_ioports_operations = {
 120         .open           = ioports_open,
 121         .read           = seq_read,
 122         .llseek         = seq_lseek,
 123         .release        = seq_release,
 124 };
 125
 126 static const struct file_operations proc_iomem_operations = {
 127         .open           = iomem_open,
 128         .read           = seq_read,
 129         .llseek         = seq_lseek,
 130         .release        = seq_release,
 131 };
 132
 133 static int __init ioresources_init(void)
 134 {
 135         proc_create("ioports", 0, NULL, &proc_ioports_operations);
 136         proc_create("iomem", 0, NULL, &proc_iomem_operations);
 137         return 0;
 138 }
 139 __initcall(ioresources_init);
 140
 141 #endif /* CONFIG_PROC_FS */
 142
 143 /* Return the conflict entry if you can't request it */
 144 static struct resource * __request_resource(struct resource *root, struct resource *new)
 145 {
 146         resource_size_t start = new->start;
 147         resource_size_t end = new->end;
 148         struct resource *tmp, **p;
 149
 150         if (end < start)
 151                 return root;
 152         if (start < root->start)
 153                 return root;
 154         if (end > root->end)
 155                 return root;
 156         p = &root->child;
 157         for (;;) {
 158                 tmp = *p;
 159                 if (!tmp || tmp->start > end) {
 160                         new->sibling = tmp;
 161                         *p = new;
 162                         new->parent = root;
 163                         return NULL;
 164                 }
 165                 p = &tmp->sibling;
 166                 if (tmp->end < start)
 167                         continue;
 168                 return tmp;
 169         }
 170 }
 171
 172 static int __release_resource(struct resource *old)
 173 {
 174         struct resource *tmp, **p;
 175
 176         p = &old->parent->child;
 177         for (;;) {
 178                 tmp = *p;
 179                 if (!tmp)
 180                         break;
 181                 if (tmp == old) {
 182                         *p = tmp->sibling;
 183                         old->parent = NULL;
 184                         return 0;
 185                 }
 186                 p = &tmp->sibling;
 187         }
 188         return -EINVAL;
 189 }
 190
 191 /**
 192  * request_resource - request and reserve an I/O or memory resource
 193  * @root: root resource descriptor
 194  * @new: resource descriptor desired by caller
 195  *
 196  * Returns 0 for success, negative error code on error.
 197  */
 198 int request_resource(struct resource *root, struct resource *new)
 199 {
 200         struct resource *conflict;
 201
 202         write_lock(&resource_lock);
 203         conflict = __request_resource(root, new);
 204         write_unlock(&resource_lock);
 205         return conflict ? -EBUSY : 0;
 206 }
 207
 208 EXPORT_SYMBOL(request_resource);
 209
 210 /**
 211  * release_resource - release a previously reserved resource
 212  * @old: resource pointer
 213  */
 214 int release_resource(struct resource *old)
 215 {
 216         int retval;
 217
 218         write_lock(&resource_lock);
 219         retval = __release_resource(old);
 220         write_unlock(&resource_lock);
 221         return retval;
 222 }
 223
 224 EXPORT_SYMBOL(release_resource);
 225
 226 #if defined(CONFIG_MEMORY_HOTPLUG) && !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 227 /*
 228  * Finds the lowest memory reosurce exists within [res->start.res->end)
 229  * the caller must specify res->start, res->end, res->flags.
 230  * If found, returns 0, res is overwritten, if not found, returns -1.
 231  */
 232 static int find_next_system_ram(struct resource *res)
 233 {
 234         resource_size_t start, end;
 235         struct resource *p;
 236
 237         BUG_ON(!res);
 238
 239         start = res->start;
 240         end = res->end;
 241         BUG_ON(start >= end);
 242
 243         read_lock(&resource_lock);
 244         for (p = iomem_resource.child; p ; p = p->sibling) {
 245                 /* system ram is just marked as IORESOURCE_MEM */
 246                 if (p->flags != res->flags)
 247                         continue;
 248                 if (p->start > end) {
 249                         p = NULL;
 250                         break;
 251                 }
 252                 if ((p->end >= start) && (p->start < end))
 253                         break;
 254         }
 255         read_unlock(&resource_lock);
 256         if (!p)
 257                 return -1;
 258         /* copy data */
 259         if (res->start < p->start)
 260                 res->start = p->start;
 261         if (res->end > p->end)
 262                 res->end = p->end;
 263         return 0;
 264 }
 265 int
 266 walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
 267                         int (*func)(unsigned long, unsigned long, void *))
 268 {
 269         struct resource res;
 270         unsigned long pfn, len;
 271         u64 orig_end;
 272         int ret = -1;
 273         res.start = (u64) start_pfn << PAGE_SHIFT;
 274         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 275         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 276         orig_end = res.end;
 277         while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
 278                 pfn = (unsigned long)(res.start >> PAGE_SHIFT);
 279                 len = (unsigned long)((res.end + 1 - res.start) >> PAGE_SHIFT);
 280                 ret = (*func)(pfn, len, arg);
 281                 if (ret)
 282                         break;
 283                 res.start = res.end + 1;
 284                 res.end = orig_end;
 285         }
 286         return ret;
 287 }
 288
 289 #endif
 290
 291 /*
 292  * Find empty slot in the resource tree given range and alignment.
 293  */
 294 static int find_resource(struct resource *root, struct resource *new,
 295                          resource_size_t size, resource_size_t min,
 296                          resource_size_t max, resource_size_t align,
 297                          void (*alignf)(void *, struct resource *,
 298                                         resource_size_t, resource_size_t),
 299                          void *alignf_data)
 300 {
 301         struct resource *this = root->child;
 302
 303         new->start = root->start;
 304         /*
 305          * Skip past an allocated resource that starts at 0, since the assignment
 306          * of this->start - 1 to new->end below would cause an underflow.
 307          */
 308         if (this && this->start == 0) {
 309                 new->start = this->end + 1;
 310                 this = this->sibling;
 311         }
 312         for(;;) {
 313                 if (this)
 314                         new->end = this->start - 1;
 315                 else
 316                         new->end = root->end;
 317                 if (new->start < min)
 318                         new->start = min;
 319                 if (new->end > max)
 320                         new->end = max;
 321                 new->start = ALIGN(new->start, align);
 322                 if (alignf)
 323                         alignf(alignf_data, new, size, align);
 324                 if (new->start < new->end && new->end - new->start >= size - 1) {
 325                         new->end = new->start + size - 1;
 326                         return 0;
 327                 }
 328                 if (!this)
 329                         break;
 330                 new->start = this->end + 1;
 331                 this = this->sibling;
 332         }
 333         return -EBUSY;
 334 }
 335
 336 /**
 337  * allocate_resource - allocate empty slot in the resource tree given range & alignment
 338  * @root: root resource descriptor
 339  * @new: resource descriptor desired by caller
 340  * @size: requested resource region size
 341  * @min: minimum size to allocate
 342  * @max: maximum size to allocate
 343  * @align: alignment requested, in bytes
 344  * @alignf: alignment function, optional, called if not NULL
 345  * @alignf_data: arbitrary data to pass to the @alignf function
 346  */
 347 int allocate_resource(struct resource *root, struct resource *new,
 348                       resource_size_t size, resource_size_t min,
 349                       resource_size_t max, resource_size_t align,
 350                       void (*alignf)(void *, struct resource *,
 351                                      resource_size_t, resource_size_t),
 352                       void *alignf_data)
 353 {
 354         int err;
 355
 356         write_lock(&resource_lock);
 357         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 358         if (err >= 0 && __request_resource(root, new))
 359                 err = -EBUSY;
 360         write_unlock(&resource_lock);
 361         return err;
 362 }
 363
 364 EXPORT_SYMBOL(allocate_resource);
 365
 366 /*
 367  * Insert a resource into the resource tree. If successful, return NULL,
 368  * otherwise return the conflicting resource (compare to __request_resource())
 369  */
 370 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 371 {
 372         struct resource *first, *next;
 373
 374         for (;; parent = first) {
 375                 first = __request_resource(parent, new);
 376                 if (!first)
 377                         return first;
 378
 379                 if (first == parent)
 380                         return first;
 381
 382                 if ((first->start > new->start) || (first->end < new->end))
 383                         break;
 384                 if ((first->start == new->start) && (first->end == new->end))
 385                         break;
 386         }
 387
 388         for (next = first; ; next = next->sibling) {
 389                 /* Partial overlap? Bad, and unfixable */
 390                 if (next->start < new->start || next->end > new->end)
 391                         return next;
 392                 if (!next->sibling)
 393                         break;
 394                 if (next->sibling->start > new->end)
 395                         break;
 396         }
 397
 398         new->parent = parent;
 399         new->sibling = next->sibling;
 400         new->child = first;
 401
 402         next->sibling = NULL;
 403         for (next = first; next; next = next->sibling)
 404                 next->parent = new;
 405
 406         if (parent->child == first) {
 407                 parent->child = new;
 408         } else {
 409                 next = parent->child;
 410                 while (next->sibling != first)
 411                         next = next->sibling;
 412                 next->sibling = new;
 413         }
 414         return NULL;
 415 }
 416
 417 /**
 418  * insert_resource - Inserts a resource in the resource tree
 419  * @parent: parent of the new resource
 420  * @new: new resource to insert
 421  *
 422  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 423  *
 424  * This function is equivalent to request_resource when no conflict
 425  * happens. If a conflict happens, and the conflicting resources
 426  * entirely fit within the range of the new resource, then the new
 427  * resource is inserted and the conflicting resources become children of
 428  * the new resource.
 429  */
 430 int insert_resource(struct resource *parent, struct resource *new)
 431 {
 432         struct resource *conflict;
 433
 434         write_lock(&resource_lock);
 435         conflict = __insert_resource(parent, new);
 436         write_unlock(&resource_lock);
 437         return conflict ? -EBUSY : 0;
 438 }
 439
 440 /**
 441  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 442  * @root: root resource descriptor
 443  * @new: new resource to insert
 444  *
 445  * Insert a resource into the resource tree, possibly expanding it in order
 446  * to make it encompass any conflicting resources.
 447  */
 448 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 449 {
 450         if (new->parent)
 451                 return;
 452
 453         write_lock(&resource_lock);
 454         for (;;) {
 455                 struct resource *conflict;
 456
 457                 conflict = __insert_resource(root, new);
 458                 if (!conflict)
 459                         break;
 460                 if (conflict == root)
 461                         break;
 462
 463                 /* Ok, expand resource to cover the conflict, then try again .. */
 464                 if (conflict->start < new->start)
 465                         new->start = conflict->start;
 466                 if (conflict->end > new->end)
 467                         new->end = conflict->end;
 468
 469                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 470         }
 471         write_unlock(&resource_lock);
 472 }
 473
 474 /**
 475  * adjust_resource - modify a resource's start and size
 476  * @res: resource to modify
 477  * @start: new start value
 478  * @size: new size
 479  *
 480  * Given an existing resource, change its start and size to match the
 481  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 482  * Existing children of the resource are assumed to be immutable.
 483  */
 484 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 485 {
 486         struct resource *tmp, *parent = res->parent;
 487         resource_size_t end = start + size - 1;
 488         int result = -EBUSY;
 489
 490         write_lock(&resource_lock);
 491
 492         if ((start < parent->start) || (end > parent->end))
 493                 goto out;
 494
 495         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 496                 if ((tmp->start < start) || (tmp->end > end))
 497                         goto out;
 498         }
 499
 500         if (res->sibling && (res->sibling->start <= end))
 501                 goto out;
 502
 503         tmp = parent->child;
 504         if (tmp != res) {
 505                 while (tmp->sibling != res)
 506                         tmp = tmp->sibling;
 507                 if (start <= tmp->end)
 508                         goto out;
 509         }
 510
 511         res->start = start;
 512         res->end = end;
 513         result = 0;
 514
 515  out:
 516         write_unlock(&resource_lock);
 517         return result;
 518 }
 519
 520 static void __init __reserve_region_with_split(struct resource *root,
 521                 resource_size_t start, resource_size_t end,
 522                 const char *name)
 523 {
 524         struct resource *parent = root;
 525         struct resource *conflict;
 526         struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
 527
 528         if (!res)
 529                 return;
 530
 531         res->name = name;
 532         res->start = start;
 533         res->end = end;
 534         res->flags = IORESOURCE_BUSY;
 535
 536         conflict = __request_resource(parent, res);
 537         if (!conflict)
 538                 return;
 539
 540         /* failed, split and try again */
 541         kfree(res);
 542
 543         /* conflict covered whole area */
 544         if (conflict->start <= start && conflict->end >= end)
 545                 return;
 546
 547         if (conflict->start > start)
 548                 __reserve_region_with_split(root, start, conflict->start-1, name);
 549         if (conflict->end < end)
 550                 __reserve_region_with_split(root, conflict->end+1, end, name);
 551 }
 552
 553 void __init reserve_region_with_split(struct resource *root,
 554                 resource_size_t start, resource_size_t end,
 555                 const char *name)
 556 {
 557         write_lock(&resource_lock);
 558         __reserve_region_with_split(root, start, end, name);
 559         write_unlock(&resource_lock);
 560 }
 561
 562 EXPORT_SYMBOL(adjust_resource);
 563
 564 /**
 565  * resource_alignment - calculate resource's alignment
 566  * @res: resource pointer
 567  *
 568  * Returns alignment on success, 0 (invalid alignment) on failure.
 569  */
 570 resource_size_t resource_alignment(struct resource *res)
 571 {
 572         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 573         case IORESOURCE_SIZEALIGN:
 574                 return resource_size(res);
 575         case IORESOURCE_STARTALIGN:
 576                 return res->start;
 577         default:
 578                 return 0;
 579         }
 580 }
 581
 582 /*
 583  * This is compatibility stuff for IO resources.
 584  *
 585  * Note how this, unlike the above, knows about
 586  * the IO flag meanings (busy etc).
 587  *
 588  * request_region creates a new busy region.
 589  *
 590  * check_region returns non-zero if the area is already busy.
 591  *
 592  * release_region releases a matching busy region.
 593  */
 594
 595 /**
 596  * __request_region - create a new busy resource region
 597  * @parent: parent resource descriptor
 598  * @start: resource start address
 599  * @n: resource region size
 600  * @name: reserving caller's ID string
 601  * @flags: IO resource flags
 602  */
 603 struct resource * __request_region(struct resource *parent,
 604                                    resource_size_t start, resource_size_t n,
 605                                    const char *name, int flags)
 606 {
 607         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 608
 609         if (!res)
 610                 return NULL;
 611
 612         res->name = name;
 613         res->start = start;
 614         res->end = start + n - 1;
 615         res->flags = IORESOURCE_BUSY;
 616         res->flags |= flags;
 617
 618         write_lock(&resource_lock);
 619
 620         for (;;) {
 621                 struct resource *conflict;
 622
 623                 conflict = __request_resource(parent, res);
 624                 if (!conflict)
 625                         break;
 626                 if (conflict != parent) {
 627                         parent = conflict;
 628                         if (!(conflict->flags & IORESOURCE_BUSY))
 629                                 continue;
 630                 }
 631
 632                 /* Uhhuh, that didn't work out.. */
 633                 kfree(res);
 634                 res = NULL;
 635                 break;
 636         }
 637         write_unlock(&resource_lock);
 638         return res;
 639 }
 640 EXPORT_SYMBOL(__request_region);
 641
 642 /**
 643  * __check_region - check if a resource region is busy or free
 644  * @parent: parent resource descriptor
 645  * @start: resource start address
 646  * @n: resource region size
 647  *
 648  * Returns 0 if the region is free at the moment it is checked,
 649  * returns %-EBUSY if the region is busy.
 650  *
 651  * NOTE:
 652  * This function is deprecated because its use is racy.
 653  * Even if it returns 0, a subsequent call to request_region()
 654  * may fail because another driver etc. just allocated the region.
 655  * Do NOT use it.  It will be removed from the kernel.
 656  */
 657 int __check_region(struct resource *parent, resource_size_t start,
 658                         resource_size_t n)
 659 {
 660         struct resource * res;
 661
 662         res = __request_region(parent, start, n, "check-region", 0);
 663         if (!res)
 664                 return -EBUSY;
 665
 666         release_resource(res);
 667         kfree(res);
 668         return 0;
 669 }
 670 EXPORT_SYMBOL(__check_region);
 671
 672 /**
 673  * __release_region - release a previously reserved resource region
 674  * @parent: parent resource descriptor
 675  * @start: resource start address
 676  * @n: resource region size
 677  *
 678  * The described resource region must match a currently busy region.
 679  */
 680 void __release_region(struct resource *parent, resource_size_t start,
 681                         resource_size_t n)
 682 {
 683         struct resource **p;
 684         resource_size_t end;
 685
 686         p = &parent->child;
 687         end = start + n - 1;
 688
 689         write_lock(&resource_lock);
 690
 691         for (;;) {
 692                 struct resource *res = *p;
 693
 694                 if (!res)
 695                         break;
 696                 if (res->start <= start && res->end >= end) {
 697                         if (!(res->flags & IORESOURCE_BUSY)) {
 698                                 p = &res->child;
 699                                 continue;
 700                         }
 701                         if (res->start != start || res->end != end)
 702                                 break;
 703                         *p = res->sibling;
 704                         write_unlock(&resource_lock);
 705                         kfree(res);
 706                         return;
 707                 }
 708                 p = &res->sibling;
 709         }
 710
 711         write_unlock(&resource_lock);
 712
 713         printk(KERN_WARNING "Trying to free nonexistent resource "
 714                 "<%016llx-%016llx>\n", (unsigned long long)start,
 715                 (unsigned long long)end);
 716 }
 717 EXPORT_SYMBOL(__release_region);
 718
 719 /*
 720  * Managed region resource
 721  */
 722 struct region_devres {
 723         struct resource *parent;
 724         resource_size_t start;
 725         resource_size_t n;
 726 };
 727
 728 static void devm_region_release(struct device *dev, void *res)
 729 {
 730         struct region_devres *this = res;
 731
 732         __release_region(this->parent, this->start, this->n);
 733 }
 734
 735 static int devm_region_match(struct device *dev, void *res, void *match_data)
 736 {
 737         struct region_devres *this = res, *match = match_data;
 738
 739         return this->parent == match->parent &&
 740                 this->start == match->start && this->n == match->n;
 741 }
 742
 743 struct resource * __devm_request_region(struct device *dev,
 744                                 struct resource *parent, resource_size_t start,
 745                                 resource_size_t n, const char *name)
 746 {
 747         struct region_devres *dr = NULL;
 748         struct resource *res;
 749
 750         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 751                           GFP_KERNEL);
 752         if (!dr)
 753                 return NULL;
 754
 755         dr->parent = parent;
 756         dr->start = start;
 757         dr->n = n;
 758
 759         res = __request_region(parent, start, n, name, 0);
 760         if (res)
 761                 devres_add(dev, dr);
 762         else
 763                 devres_free(dr);
 764
 765         return res;
 766 }
 767 EXPORT_SYMBOL(__devm_request_region);
 768
 769 void __devm_release_region(struct device *dev, struct resource *parent,
 770                            resource_size_t start, resource_size_t n)
 771 {
 772         struct region_devres match_data = { parent, start, n };
 773
 774         __release_region(parent, start, n);
 775         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
 776                                &match_data));
 777 }
 778 EXPORT_SYMBOL(__devm_release_region);
 779
 780 /*
 781  * Called from init/main.c to reserve IO ports.
 782  */
 783 #define MAXRESERVE 4
 784 static int __init reserve_setup(char *str)
 785 {
 786         static int reserved;
 787         static struct resource reserve[MAXRESERVE];
 788
 789         for (;;) {
 790                 unsigned int io_start, io_num;
 791                 int x = reserved;
 792
 793                 if (get_option (&str, &io_start) != 2)
 794                         break;
 795                 if (get_option (&str, &io_num)   == 0)
 796                         break;
 797                 if (x < MAXRESERVE) {
 798                         struct resource *res = reserve + x;
 799                         res->name = "reserved";
 800                         res->start = io_start;
 801                         res->end = io_start + io_num - 1;
 802                         res->flags = IORESOURCE_BUSY;
 803                         res->child = NULL;
 804                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 805                                 reserved = x+1;
 806                 }
 807         }
 808         return 1;
 809 }
 810
 811 __setup("reserve=", reserve_setup);
 812
 813 /*
 814  * Check if the requested addr and size spans more than any slot in the
 815  * iomem resource tree.
 816  */
 817 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
 818 {
 819         struct resource *p = &iomem_resource;
 820         int err = 0;
 821         loff_t l;
 822
 823         read_lock(&resource_lock);
 824         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 825                 /*
 826                  * We can probably skip the resources without
 827                  * IORESOURCE_IO attribute?
 828                  */
 829                 if (p->start >= addr + size)
 830                         continue;
 831                 if (p->end < addr)
 832                         continue;
 833                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
 834                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
 835                         continue;
 836                 /*
 837                  * if a resource is "BUSY", it's not a hardware resource
 838                  * but a driver mapping of such a resource; we don't want
 839                  * to warn for those; some drivers legitimately map only
 840                  * partial hardware resources. (example: vesafb)
 841                  */
 842                 if (p->flags & IORESOURCE_BUSY)
 843                         continue;
 844
 845                 printk(KERN_WARNING "resource map sanity check conflict: "
 846                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
 847                        (unsigned long long)addr,
 848                        (unsigned long long)(addr + size - 1),
 849                        (unsigned long long)p->start,
 850                        (unsigned long long)p->end,
 851                        p->name);
 852                 err = -1;
 853                 break;
 854         }
 855         read_unlock(&resource_lock);
 856
 857         return err;
 858 }
 859
 860 #ifdef CONFIG_STRICT_DEVMEM
 861 static int strict_iomem_checks = 1;
 862 #else
 863 static int strict_iomem_checks;
 864 #endif
 865
 866 /*
 867  * check if an address is reserved in the iomem resource tree
 868  * returns 1 if reserved, 0 if not reserved.
 869  */
 870 int iomem_is_exclusive(u64 addr)
 871 {
 872         struct resource *p = &iomem_resource;
 873         int err = 0;
 874         loff_t l;
 875         int size = PAGE_SIZE;
 876
 877         if (!strict_iomem_checks)
 878                 return 0;
 879
 880         addr = addr & PAGE_MASK;
 881
 882         read_lock(&resource_lock);
 883         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 884                 /*
 885                  * We can probably skip the resources without
 886                  * IORESOURCE_IO attribute?
 887                  */
 888                 if (p->start >= addr + size)
 889                         break;
 890                 if (p->end < addr)
 891                         continue;
 892                 if (p->flags & IORESOURCE_BUSY &&
 893                      p->flags & IORESOURCE_EXCLUSIVE) {
 894                         err = 1;
 895                         break;
 896                 }
 897         }
 898         read_unlock(&resource_lock);
 899
 900         return err;
 901 }
 902
 903 static int __init strict_iomem(char *str)
 904 {
 905         if (strstr(str, "relaxed"))
 906                 strict_iomem_checks = 0;
 907         if (strstr(str, "strict"))
 908                 strict_iomem_checks = 1;
 909         return 1;
 910 }
 911
 912 __setup("iomem=", strict_iomem);