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