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_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 and "name".
 230  * If found, returns 0, res is overwritten, if not found, returns -1.
 231  */
 232 static int find_next_system_ram(struct resource *res, char *name)
 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 (name && strcmp(p->name, name))
 249                         continue;
 250                 if (p->start > end) {
 251                         p = NULL;
 252                         break;
 253                 }
 254                 if ((p->end >= start) && (p->start < end))
 255                         break;
 256         }
 257         read_unlock(&resource_lock);
 258         if (!p)
 259                 return -1;
 260         /* copy data */
 261         if (res->start < p->start)
 262                 res->start = p->start;
 263         if (res->end > p->end)
 264                 res->end = p->end;
 265         return 0;
 266 }
 267
 268 /*
 269  * This function calls callback against all memory range of "System RAM"
 270  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 271  * Now, this function is only for "System RAM".
 272  */
 273 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 274                 void *arg, int (*func)(unsigned long, unsigned long, void *))
 275 {
 276         struct resource res;
 277         unsigned long pfn, len;
 278         u64 orig_end;
 279         int ret = -1;
 280
 281         res.start = (u64) start_pfn << PAGE_SHIFT;
 282         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 283         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 284         orig_end = res.end;
 285         while ((res.start < res.end) &&
 286                 (find_next_system_ram(&res, "System RAM") >= 0)) {
 287                 pfn = (unsigned long)(res.start >> PAGE_SHIFT);
 288                 len = (unsigned long)((res.end + 1 - res.start) >> PAGE_SHIFT);
 289                 ret = (*func)(pfn, len, arg);
 290                 if (ret)
 291                         break;
 292                 res.start = res.end + 1;
 293                 res.end = orig_end;
 294         }
 295         return ret;
 296 }
 297
 298 #endif
 299
 300 /*
 301  * Find empty slot in the resource tree given range and alignment.
 302  */
 303 static int find_resource(struct resource *root, struct resource *new,
 304                          resource_size_t size, resource_size_t min,
 305                          resource_size_t max, resource_size_t align,
 306                          void (*alignf)(void *, struct resource *,
 307                                         resource_size_t, resource_size_t),
 308                          void *alignf_data)
 309 {
 310         struct resource *this = root->child;
 311         resource_size_t start, end;
 312
 313         start = root->start;
 314         /*
 315          * Skip past an allocated resource that starts at 0, since the assignment
 316          * of this->start - 1 to new->end below would cause an underflow.
 317          */
 318         if (this && this->start == 0) {
 319                 start = this->end + 1;
 320                 this = this->sibling;
 321         }
 322         for(;;) {
 323                 if (this)
 324                         end = this->start - 1;
 325                 else
 326                         end = root->end;
 327                 if (start < min)
 328                         start = min;
 329                 if (end > max)
 330                         end = max;
 331                 start = ALIGN(start, align);
 332                 if (alignf)
 333                         alignf(alignf_data, new, size, align);
 334                 if (start < end && end - start >= size - 1) {
 335                         new->start = start;
 336                         new->end = start + size - 1;
 337                         return 0;
 338                 }
 339                 if (!this)
 340                         break;
 341                 start = this->end + 1;
 342                 this = this->sibling;
 343         }
 344         return -EBUSY;
 345 }
 346
 347 /**
 348  * allocate_resource - allocate empty slot in the resource tree given range & alignment
 349  * @root: root resource descriptor
 350  * @new: resource descriptor desired by caller
 351  * @size: requested resource region size
 352  * @min: minimum size to allocate
 353  * @max: maximum size to allocate
 354  * @align: alignment requested, in bytes
 355  * @alignf: alignment function, optional, called if not NULL
 356  * @alignf_data: arbitrary data to pass to the @alignf function
 357  */
 358 int allocate_resource(struct resource *root, struct resource *new,
 359                       resource_size_t size, resource_size_t min,
 360                       resource_size_t max, resource_size_t align,
 361                       void (*alignf)(void *, struct resource *,
 362                                      resource_size_t, resource_size_t),
 363                       void *alignf_data)
 364 {
 365         int err;
 366
 367         write_lock(&resource_lock);
 368         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 369         if (err >= 0 && __request_resource(root, new))
 370                 err = -EBUSY;
 371         write_unlock(&resource_lock);
 372         return err;
 373 }
 374
 375 EXPORT_SYMBOL(allocate_resource);
 376
 377 /*
 378  * Insert a resource into the resource tree. If successful, return NULL,
 379  * otherwise return the conflicting resource (compare to __request_resource())
 380  */
 381 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 382 {
 383         struct resource *first, *next;
 384
 385         for (;; parent = first) {
 386                 first = __request_resource(parent, new);
 387                 if (!first)
 388                         return first;
 389
 390                 if (first == parent)
 391                         return first;
 392
 393                 if ((first->start > new->start) || (first->end < new->end))
 394                         break;
 395                 if ((first->start == new->start) && (first->end == new->end))
 396                         break;
 397         }
 398
 399         for (next = first; ; next = next->sibling) {
 400                 /* Partial overlap? Bad, and unfixable */
 401                 if (next->start < new->start || next->end > new->end)
 402                         return next;
 403                 if (!next->sibling)
 404                         break;
 405                 if (next->sibling->start > new->end)
 406                         break;
 407         }
 408
 409         new->parent = parent;
 410         new->sibling = next->sibling;
 411         new->child = first;
 412
 413         next->sibling = NULL;
 414         for (next = first; next; next = next->sibling)
 415                 next->parent = new;
 416
 417         if (parent->child == first) {
 418                 parent->child = new;
 419         } else {
 420                 next = parent->child;
 421                 while (next->sibling != first)
 422                         next = next->sibling;
 423                 next->sibling = new;
 424         }
 425         return NULL;
 426 }
 427
 428 /**
 429  * insert_resource - Inserts a resource in the resource tree
 430  * @parent: parent of the new resource
 431  * @new: new resource to insert
 432  *
 433  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 434  *
 435  * This function is equivalent to request_resource when no conflict
 436  * happens. If a conflict happens, and the conflicting resources
 437  * entirely fit within the range of the new resource, then the new
 438  * resource is inserted and the conflicting resources become children of
 439  * the new resource.
 440  */
 441 int insert_resource(struct resource *parent, struct resource *new)
 442 {
 443         struct resource *conflict;
 444
 445         write_lock(&resource_lock);
 446         conflict = __insert_resource(parent, new);
 447         write_unlock(&resource_lock);
 448         return conflict ? -EBUSY : 0;
 449 }
 450
 451 /**
 452  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 453  * @root: root resource descriptor
 454  * @new: new resource to insert
 455  *
 456  * Insert a resource into the resource tree, possibly expanding it in order
 457  * to make it encompass any conflicting resources.
 458  */
 459 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 460 {
 461         if (new->parent)
 462                 return;
 463
 464         write_lock(&resource_lock);
 465         for (;;) {
 466                 struct resource *conflict;
 467
 468                 conflict = __insert_resource(root, new);
 469                 if (!conflict)
 470                         break;
 471                 if (conflict == root)
 472                         break;
 473
 474                 /* Ok, expand resource to cover the conflict, then try again .. */
 475                 if (conflict->start < new->start)
 476                         new->start = conflict->start;
 477                 if (conflict->end > new->end)
 478                         new->end = conflict->end;
 479
 480                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 481         }
 482         write_unlock(&resource_lock);
 483 }
 484
 485 /**
 486  * adjust_resource - modify a resource's start and size
 487  * @res: resource to modify
 488  * @start: new start value
 489  * @size: new size
 490  *
 491  * Given an existing resource, change its start and size to match the
 492  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 493  * Existing children of the resource are assumed to be immutable.
 494  */
 495 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 496 {
 497         struct resource *tmp, *parent = res->parent;
 498         resource_size_t end = start + size - 1;
 499         int result = -EBUSY;
 500
 501         write_lock(&resource_lock);
 502
 503         if ((start < parent->start) || (end > parent->end))
 504                 goto out;
 505
 506         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 507                 if ((tmp->start < start) || (tmp->end > end))
 508                         goto out;
 509         }
 510
 511         if (res->sibling && (res->sibling->start <= end))
 512                 goto out;
 513
 514         tmp = parent->child;
 515         if (tmp != res) {
 516                 while (tmp->sibling != res)
 517                         tmp = tmp->sibling;
 518                 if (start <= tmp->end)
 519                         goto out;
 520         }
 521
 522         res->start = start;
 523         res->end = end;
 524         result = 0;
 525
 526  out:
 527         write_unlock(&resource_lock);
 528         return result;
 529 }
 530
 531 static void __init __reserve_region_with_split(struct resource *root,
 532                 resource_size_t start, resource_size_t end,
 533                 const char *name)
 534 {
 535         struct resource *parent = root;
 536         struct resource *conflict;
 537         struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
 538
 539         if (!res)
 540                 return;
 541
 542         res->name = name;
 543         res->start = start;
 544         res->end = end;
 545         res->flags = IORESOURCE_BUSY;
 546
 547         conflict = __request_resource(parent, res);
 548         if (!conflict)
 549                 return;
 550
 551         /* failed, split and try again */
 552         kfree(res);
 553
 554         /* conflict covered whole area */
 555         if (conflict->start <= start && conflict->end >= end)
 556                 return;
 557
 558         if (conflict->start > start)
 559                 __reserve_region_with_split(root, start, conflict->start-1, name);
 560         if (conflict->end < end)
 561                 __reserve_region_with_split(root, conflict->end+1, end, name);
 562 }
 563
 564 void __init reserve_region_with_split(struct resource *root,
 565                 resource_size_t start, resource_size_t end,
 566                 const char *name)
 567 {
 568         write_lock(&resource_lock);
 569         __reserve_region_with_split(root, start, end, name);
 570         write_unlock(&resource_lock);
 571 }
 572
 573 EXPORT_SYMBOL(adjust_resource);
 574
 575 /**
 576  * resource_alignment - calculate resource's alignment
 577  * @res: resource pointer
 578  *
 579  * Returns alignment on success, 0 (invalid alignment) on failure.
 580  */
 581 resource_size_t resource_alignment(struct resource *res)
 582 {
 583         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 584         case IORESOURCE_SIZEALIGN:
 585                 return resource_size(res);
 586         case IORESOURCE_STARTALIGN:
 587                 return res->start;
 588         default:
 589                 return 0;
 590         }
 591 }
 592
 593 /*
 594  * This is compatibility stuff for IO resources.
 595  *
 596  * Note how this, unlike the above, knows about
 597  * the IO flag meanings (busy etc).
 598  *
 599  * request_region creates a new busy region.
 600  *
 601  * check_region returns non-zero if the area is already busy.
 602  *
 603  * release_region releases a matching busy region.
 604  */
 605
 606 /**
 607  * __request_region - create a new busy resource region
 608  * @parent: parent resource descriptor
 609  * @start: resource start address
 610  * @n: resource region size
 611  * @name: reserving caller's ID string
 612  * @flags: IO resource flags
 613  */
 614 struct resource * __request_region(struct resource *parent,
 615                                    resource_size_t start, resource_size_t n,
 616                                    const char *name, int flags)
 617 {
 618         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 619
 620         if (!res)
 621                 return NULL;
 622
 623         res->name = name;
 624         res->start = start;
 625         res->end = start + n - 1;
 626         res->flags = IORESOURCE_BUSY;
 627         res->flags |= flags;
 628
 629         write_lock(&resource_lock);
 630
 631         for (;;) {
 632                 struct resource *conflict;
 633
 634                 conflict = __request_resource(parent, res);
 635                 if (!conflict)
 636                         break;
 637                 if (conflict != parent) {
 638                         parent = conflict;
 639                         if (!(conflict->flags & IORESOURCE_BUSY))
 640                                 continue;
 641                 }
 642
 643                 /* Uhhuh, that didn't work out.. */
 644                 kfree(res);
 645                 res = NULL;
 646                 break;
 647         }
 648         write_unlock(&resource_lock);
 649         return res;
 650 }
 651 EXPORT_SYMBOL(__request_region);
 652
 653 /**
 654  * __check_region - check if a resource region is busy or free
 655  * @parent: parent resource descriptor
 656  * @start: resource start address
 657  * @n: resource region size
 658  *
 659  * Returns 0 if the region is free at the moment it is checked,
 660  * returns %-EBUSY if the region is busy.
 661  *
 662  * NOTE:
 663  * This function is deprecated because its use is racy.
 664  * Even if it returns 0, a subsequent call to request_region()
 665  * may fail because another driver etc. just allocated the region.
 666  * Do NOT use it.  It will be removed from the kernel.
 667  */
 668 int __check_region(struct resource *parent, resource_size_t start,
 669                         resource_size_t n)
 670 {
 671         struct resource * res;
 672
 673         res = __request_region(parent, start, n, "check-region", 0);
 674         if (!res)
 675                 return -EBUSY;
 676
 677         release_resource(res);
 678         kfree(res);
 679         return 0;
 680 }
 681 EXPORT_SYMBOL(__check_region);
 682
 683 /**
 684  * __release_region - release a previously reserved resource region
 685  * @parent: parent resource descriptor
 686  * @start: resource start address
 687  * @n: resource region size
 688  *
 689  * The described resource region must match a currently busy region.
 690  */
 691 void __release_region(struct resource *parent, resource_size_t start,
 692                         resource_size_t n)
 693 {
 694         struct resource **p;
 695         resource_size_t end;
 696
 697         p = &parent->child;
 698         end = start + n - 1;
 699
 700         write_lock(&resource_lock);
 701
 702         for (;;) {
 703                 struct resource *res = *p;
 704
 705                 if (!res)
 706                         break;
 707                 if (res->start <= start && res->end >= end) {
 708                         if (!(res->flags & IORESOURCE_BUSY)) {
 709                                 p = &res->child;
 710                                 continue;
 711                         }
 712                         if (res->start != start || res->end != end)
 713                                 break;
 714                         *p = res->sibling;
 715                         write_unlock(&resource_lock);
 716                         kfree(res);
 717                         return;
 718                 }
 719                 p = &res->sibling;
 720         }
 721
 722         write_unlock(&resource_lock);
 723
 724         printk(KERN_WARNING "Trying to free nonexistent resource "
 725                 "<%016llx-%016llx>\n", (unsigned long long)start,
 726                 (unsigned long long)end);
 727 }
 728 EXPORT_SYMBOL(__release_region);
 729
 730 /*
 731  * Managed region resource
 732  */
 733 struct region_devres {
 734         struct resource *parent;
 735         resource_size_t start;
 736         resource_size_t n;
 737 };
 738
 739 static void devm_region_release(struct device *dev, void *res)
 740 {
 741         struct region_devres *this = res;
 742
 743         __release_region(this->parent, this->start, this->n);
 744 }
 745
 746 static int devm_region_match(struct device *dev, void *res, void *match_data)
 747 {
 748         struct region_devres *this = res, *match = match_data;
 749
 750         return this->parent == match->parent &&
 751                 this->start == match->start && this->n == match->n;
 752 }
 753
 754 struct resource * __devm_request_region(struct device *dev,
 755                                 struct resource *parent, resource_size_t start,
 756                                 resource_size_t n, const char *name)
 757 {
 758         struct region_devres *dr = NULL;
 759         struct resource *res;
 760
 761         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 762                           GFP_KERNEL);
 763         if (!dr)
 764                 return NULL;
 765
 766         dr->parent = parent;
 767         dr->start = start;
 768         dr->n = n;
 769
 770         res = __request_region(parent, start, n, name, 0);
 771         if (res)
 772                 devres_add(dev, dr);
 773         else
 774                 devres_free(dr);
 775
 776         return res;
 777 }
 778 EXPORT_SYMBOL(__devm_request_region);
 779
 780 void __devm_release_region(struct device *dev, struct resource *parent,
 781                            resource_size_t start, resource_size_t n)
 782 {
 783         struct region_devres match_data = { parent, start, n };
 784
 785         __release_region(parent, start, n);
 786         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
 787                                &match_data));
 788 }
 789 EXPORT_SYMBOL(__devm_release_region);
 790
 791 /*
 792  * Called from init/main.c to reserve IO ports.
 793  */
 794 #define MAXRESERVE 4
 795 static int __init reserve_setup(char *str)
 796 {
 797         static int reserved;
 798         static struct resource reserve[MAXRESERVE];
 799
 800         for (;;) {
 801                 unsigned int io_start, io_num;
 802                 int x = reserved;
 803
 804                 if (get_option (&str, &io_start) != 2)
 805                         break;
 806                 if (get_option (&str, &io_num)   == 0)
 807                         break;
 808                 if (x < MAXRESERVE) {
 809                         struct resource *res = reserve + x;
 810                         res->name = "reserved";
 811                         res->start = io_start;
 812                         res->end = io_start + io_num - 1;
 813                         res->flags = IORESOURCE_BUSY;
 814                         res->child = NULL;
 815                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 816                                 reserved = x+1;
 817                 }
 818         }
 819         return 1;
 820 }
 821
 822 __setup("reserve=", reserve_setup);
 823
 824 /*
 825  * Check if the requested addr and size spans more than any slot in the
 826  * iomem resource tree.
 827  */
 828 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
 829 {
 830         struct resource *p = &iomem_resource;
 831         int err = 0;
 832         loff_t l;
 833
 834         read_lock(&resource_lock);
 835         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 836                 /*
 837                  * We can probably skip the resources without
 838                  * IORESOURCE_IO attribute?
 839                  */
 840                 if (p->start >= addr + size)
 841                         continue;
 842                 if (p->end < addr)
 843                         continue;
 844                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
 845                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
 846                         continue;
 847                 /*
 848                  * if a resource is "BUSY", it's not a hardware resource
 849                  * but a driver mapping of such a resource; we don't want
 850                  * to warn for those; some drivers legitimately map only
 851                  * partial hardware resources. (example: vesafb)
 852                  */
 853                 if (p->flags & IORESOURCE_BUSY)
 854                         continue;
 855
 856                 printk(KERN_WARNING "resource map sanity check conflict: "
 857                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
 858                        (unsigned long long)addr,
 859                        (unsigned long long)(addr + size - 1),
 860                        (unsigned long long)p->start,
 861                        (unsigned long long)p->end,
 862                        p->name);
 863                 err = -1;
 864                 break;
 865         }
 866         read_unlock(&resource_lock);
 867
 868         return err;
 869 }
 870
 871 #ifdef CONFIG_STRICT_DEVMEM
 872 static int strict_iomem_checks = 1;
 873 #else
 874 static int strict_iomem_checks;
 875 #endif
 876
 877 /*
 878  * check if an address is reserved in the iomem resource tree
 879  * returns 1 if reserved, 0 if not reserved.
 880  */
 881 int iomem_is_exclusive(u64 addr)
 882 {
 883         struct resource *p = &iomem_resource;
 884         int err = 0;
 885         loff_t l;
 886         int size = PAGE_SIZE;
 887
 888         if (!strict_iomem_checks)
 889                 return 0;
 890
 891         addr = addr & PAGE_MASK;
 892
 893         read_lock(&resource_lock);
 894         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 895                 /*
 896                  * We can probably skip the resources without
 897                  * IORESOURCE_IO attribute?
 898                  */
 899                 if (p->start >= addr + size)
 900                         break;
 901                 if (p->end < addr)
 902                         continue;
 903                 if (p->flags & IORESOURCE_BUSY &&
 904                      p->flags & IORESOURCE_EXCLUSIVE) {
 905                         err = 1;
 906                         break;
 907                 }
 908         }
 909         read_unlock(&resource_lock);
 910
 911         return err;
 912 }
 913
 914 static int __init strict_iomem(char *str)
 915 {
 916         if (strstr(str, "relaxed"))
 917                 strict_iomem_checks = 0;
 918         if (strstr(str, "strict"))
 919                 strict_iomem_checks = 1;
 920         return 1;
 921 }
 922
 923 __setup("iomem=", strict_iomem);