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 /*
 361  * Find empty slot in the resource tree given range and alignment.
 362  */
 363 static int find_resource(struct resource *root, struct resource *new,
 364                          resource_size_t size, resource_size_t min,
 365                          resource_size_t max, resource_size_t align,
 366                          resource_size_t (*alignf)(void *,
 367                                                    const struct resource *,
 368                                                    resource_size_t,
 369                                                    resource_size_t),
 370                          void *alignf_data)
 371 {
 372         struct resource *this = root->child;
 373         struct resource tmp = *new;
 374
 375         tmp.start = root->start;
 376         /*
 377          * Skip past an allocated resource that starts at 0, since the assignment
 378          * of this->start - 1 to tmp->end below would cause an underflow.
 379          */
 380         if (this && this->start == 0) {
 381                 tmp.start = this->end + 1;
 382                 this = this->sibling;
 383         }
 384         for(;;) {
 385                 if (this)
 386                         tmp.end = this->start - 1;
 387                 else
 388                         tmp.end = root->end;
 389                 if (tmp.start < min)
 390                         tmp.start = min;
 391                 if (tmp.end > max)
 392                         tmp.end = max;
 393                 tmp.start = ALIGN(tmp.start, align);
 394                 if (alignf)
 395                         tmp.start = alignf(alignf_data, &tmp, size, align);
 396                 if (tmp.start < tmp.end && tmp.end - tmp.start >= size - 1) {
 397                         new->start = tmp.start;
 398                         new->end = tmp.start + size - 1;
 399                         return 0;
 400                 }
 401                 if (!this)
 402                         break;
 403                 tmp.start = this->end + 1;
 404                 this = this->sibling;
 405         }
 406         return -EBUSY;
 407 }
 408
 409 /**
 410  * allocate_resource - allocate empty slot in the resource tree given range & alignment
 411  * @root: root resource descriptor
 412  * @new: resource descriptor desired by caller
 413  * @size: requested resource region size
 414  * @min: minimum size to allocate
 415  * @max: maximum size to allocate
 416  * @align: alignment requested, in bytes
 417  * @alignf: alignment function, optional, called if not NULL
 418  * @alignf_data: arbitrary data to pass to the @alignf function
 419  */
 420 int allocate_resource(struct resource *root, struct resource *new,
 421                       resource_size_t size, resource_size_t min,
 422                       resource_size_t max, resource_size_t align,
 423                       resource_size_t (*alignf)(void *,
 424                                                 const struct resource *,
 425                                                 resource_size_t,
 426                                                 resource_size_t),
 427                       void *alignf_data)
 428 {
 429         int err;
 430
 431         write_lock(&resource_lock);
 432         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 433         if (err >= 0 && __request_resource(root, new))
 434                 err = -EBUSY;
 435         write_unlock(&resource_lock);
 436         return err;
 437 }
 438
 439 EXPORT_SYMBOL(allocate_resource);
 440
 441 /*
 442  * Insert a resource into the resource tree. If successful, return NULL,
 443  * otherwise return the conflicting resource (compare to __request_resource())
 444  */
 445 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 446 {
 447         struct resource *first, *next;
 448
 449         for (;; parent = first) {
 450                 first = __request_resource(parent, new);
 451                 if (!first)
 452                         return first;
 453
 454                 if (first == parent)
 455                         return first;
 456
 457                 if ((first->start > new->start) || (first->end < new->end))
 458                         break;
 459                 if ((first->start == new->start) && (first->end == new->end))
 460                         break;
 461         }
 462
 463         for (next = first; ; next = next->sibling) {
 464                 /* Partial overlap? Bad, and unfixable */
 465                 if (next->start < new->start || next->end > new->end)
 466                         return next;
 467                 if (!next->sibling)
 468                         break;
 469                 if (next->sibling->start > new->end)
 470                         break;
 471         }
 472
 473         new->parent = parent;
 474         new->sibling = next->sibling;
 475         new->child = first;
 476
 477         next->sibling = NULL;
 478         for (next = first; next; next = next->sibling)
 479                 next->parent = new;
 480
 481         if (parent->child == first) {
 482                 parent->child = new;
 483         } else {
 484                 next = parent->child;
 485                 while (next->sibling != first)
 486                         next = next->sibling;
 487                 next->sibling = new;
 488         }
 489         return NULL;
 490 }
 491
 492 /**
 493  * insert_resource_conflict - Inserts resource in the resource tree
 494  * @parent: parent of the new resource
 495  * @new: new resource to insert
 496  *
 497  * Returns 0 on success, conflict resource if the resource can't be inserted.
 498  *
 499  * This function is equivalent to request_resource_conflict when no conflict
 500  * happens. If a conflict happens, and the conflicting resources
 501  * entirely fit within the range of the new resource, then the new
 502  * resource is inserted and the conflicting resources become children of
 503  * the new resource.
 504  */
 505 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 506 {
 507         struct resource *conflict;
 508
 509         write_lock(&resource_lock);
 510         conflict = __insert_resource(parent, new);
 511         write_unlock(&resource_lock);
 512         return conflict;
 513 }
 514
 515 /**
 516  * insert_resource - Inserts a resource in the resource tree
 517  * @parent: parent of the new resource
 518  * @new: new resource to insert
 519  *
 520  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 521  */
 522 int insert_resource(struct resource *parent, struct resource *new)
 523 {
 524         struct resource *conflict;
 525
 526         conflict = insert_resource_conflict(parent, new);
 527         return conflict ? -EBUSY : 0;
 528 }
 529
 530 /**
 531  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 532  * @root: root resource descriptor
 533  * @new: new resource to insert
 534  *
 535  * Insert a resource into the resource tree, possibly expanding it in order
 536  * to make it encompass any conflicting resources.
 537  */
 538 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 539 {
 540         if (new->parent)
 541                 return;
 542
 543         write_lock(&resource_lock);
 544         for (;;) {
 545                 struct resource *conflict;
 546
 547                 conflict = __insert_resource(root, new);
 548                 if (!conflict)
 549                         break;
 550                 if (conflict == root)
 551                         break;
 552
 553                 /* Ok, expand resource to cover the conflict, then try again .. */
 554                 if (conflict->start < new->start)
 555                         new->start = conflict->start;
 556                 if (conflict->end > new->end)
 557                         new->end = conflict->end;
 558
 559                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 560         }
 561         write_unlock(&resource_lock);
 562 }
 563
 564 /**
 565  * adjust_resource - modify a resource's start and size
 566  * @res: resource to modify
 567  * @start: new start value
 568  * @size: new size
 569  *
 570  * Given an existing resource, change its start and size to match the
 571  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 572  * Existing children of the resource are assumed to be immutable.
 573  */
 574 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 575 {
 576         struct resource *tmp, *parent = res->parent;
 577         resource_size_t end = start + size - 1;
 578         int result = -EBUSY;
 579
 580         write_lock(&resource_lock);
 581
 582         if ((start < parent->start) || (end > parent->end))
 583                 goto out;
 584
 585         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 586                 if ((tmp->start < start) || (tmp->end > end))
 587                         goto out;
 588         }
 589
 590         if (res->sibling && (res->sibling->start <= end))
 591                 goto out;
 592
 593         tmp = parent->child;
 594         if (tmp != res) {
 595                 while (tmp->sibling != res)
 596                         tmp = tmp->sibling;
 597                 if (start <= tmp->end)
 598                         goto out;
 599         }
 600
 601         res->start = start;
 602         res->end = end;
 603         result = 0;
 604
 605  out:
 606         write_unlock(&resource_lock);
 607         return result;
 608 }
 609
 610 static void __init __reserve_region_with_split(struct resource *root,
 611                 resource_size_t start, resource_size_t end,
 612                 const char *name)
 613 {
 614         struct resource *parent = root;
 615         struct resource *conflict;
 616         struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
 617
 618         if (!res)
 619                 return;
 620
 621         res->name = name;
 622         res->start = start;
 623         res->end = end;
 624         res->flags = IORESOURCE_BUSY;
 625
 626         conflict = __request_resource(parent, res);
 627         if (!conflict)
 628                 return;
 629
 630         /* failed, split and try again */
 631         kfree(res);
 632
 633         /* conflict covered whole area */
 634         if (conflict->start <= start && conflict->end >= end)
 635                 return;
 636
 637         if (conflict->start > start)
 638                 __reserve_region_with_split(root, start, conflict->start-1, name);
 639         if (conflict->end < end)
 640                 __reserve_region_with_split(root, conflict->end+1, end, name);
 641 }
 642
 643 void __init reserve_region_with_split(struct resource *root,
 644                 resource_size_t start, resource_size_t end,
 645                 const char *name)
 646 {
 647         write_lock(&resource_lock);
 648         __reserve_region_with_split(root, start, end, name);
 649         write_unlock(&resource_lock);
 650 }
 651
 652 EXPORT_SYMBOL(adjust_resource);
 653
 654 /**
 655  * resource_alignment - calculate resource's alignment
 656  * @res: resource pointer
 657  *
 658  * Returns alignment on success, 0 (invalid alignment) on failure.
 659  */
 660 resource_size_t resource_alignment(struct resource *res)
 661 {
 662         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 663         case IORESOURCE_SIZEALIGN:
 664                 return resource_size(res);
 665         case IORESOURCE_STARTALIGN:
 666                 return res->start;
 667         default:
 668                 return 0;
 669         }
 670 }
 671
 672 /*
 673  * This is compatibility stuff for IO resources.
 674  *
 675  * Note how this, unlike the above, knows about
 676  * the IO flag meanings (busy etc).
 677  *
 678  * request_region creates a new busy region.
 679  *
 680  * check_region returns non-zero if the area is already busy.
 681  *
 682  * release_region releases a matching busy region.
 683  */
 684
 685 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
 686
 687 /**
 688  * __request_region - create a new busy resource region
 689  * @parent: parent resource descriptor
 690  * @start: resource start address
 691  * @n: resource region size
 692  * @name: reserving caller's ID string
 693  * @flags: IO resource flags
 694  */
 695 struct resource * __request_region(struct resource *parent,
 696                                    resource_size_t start, resource_size_t n,
 697                                    const char *name, int flags)
 698 {
 699         DECLARE_WAITQUEUE(wait, current);
 700         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 701
 702         if (!res)
 703                 return NULL;
 704
 705         res->name = name;
 706         res->start = start;
 707         res->end = start + n - 1;
 708         res->flags = IORESOURCE_BUSY;
 709         res->flags |= flags;
 710
 711         write_lock(&resource_lock);
 712
 713         for (;;) {
 714                 struct resource *conflict;
 715
 716                 conflict = __request_resource(parent, res);
 717                 if (!conflict)
 718                         break;
 719                 if (conflict != parent) {
 720                         parent = conflict;
 721                         if (!(conflict->flags & IORESOURCE_BUSY))
 722                                 continue;
 723                 }
 724                 if (conflict->flags & flags & IORESOURCE_MUXED) {
 725                         add_wait_queue(&muxed_resource_wait, &wait);
 726                         write_unlock(&resource_lock);
 727                         set_current_state(TASK_UNINTERRUPTIBLE);
 728                         schedule();
 729                         remove_wait_queue(&muxed_resource_wait, &wait);
 730                         write_lock(&resource_lock);
 731                         continue;
 732                 }
 733                 /* Uhhuh, that didn't work out.. */
 734                 kfree(res);
 735                 res = NULL;
 736                 break;
 737         }
 738         write_unlock(&resource_lock);
 739         return res;
 740 }
 741 EXPORT_SYMBOL(__request_region);
 742
 743 /**
 744  * __check_region - check if a resource region is busy or free
 745  * @parent: parent resource descriptor
 746  * @start: resource start address
 747  * @n: resource region size
 748  *
 749  * Returns 0 if the region is free at the moment it is checked,
 750  * returns %-EBUSY if the region is busy.
 751  *
 752  * NOTE:
 753  * This function is deprecated because its use is racy.
 754  * Even if it returns 0, a subsequent call to request_region()
 755  * may fail because another driver etc. just allocated the region.
 756  * Do NOT use it.  It will be removed from the kernel.
 757  */
 758 int __check_region(struct resource *parent, resource_size_t start,
 759                         resource_size_t n)
 760 {
 761         struct resource * res;
 762
 763         res = __request_region(parent, start, n, "check-region", 0);
 764         if (!res)
 765                 return -EBUSY;
 766
 767         release_resource(res);
 768         kfree(res);
 769         return 0;
 770 }
 771 EXPORT_SYMBOL(__check_region);
 772
 773 /**
 774  * __release_region - release a previously reserved resource region
 775  * @parent: parent resource descriptor
 776  * @start: resource start address
 777  * @n: resource region size
 778  *
 779  * The described resource region must match a currently busy region.
 780  */
 781 void __release_region(struct resource *parent, resource_size_t start,
 782                         resource_size_t n)
 783 {
 784         struct resource **p;
 785         resource_size_t end;
 786
 787         p = &parent->child;
 788         end = start + n - 1;
 789
 790         write_lock(&resource_lock);
 791
 792         for (;;) {
 793                 struct resource *res = *p;
 794
 795                 if (!res)
 796                         break;
 797                 if (res->start <= start && res->end >= end) {
 798                         if (!(res->flags & IORESOURCE_BUSY)) {
 799                                 p = &res->child;
 800                                 continue;
 801                         }
 802                         if (res->start != start || res->end != end)
 803                                 break;
 804                         *p = res->sibling;
 805                         write_unlock(&resource_lock);
 806                         if (res->flags & IORESOURCE_MUXED)
 807                                 wake_up(&muxed_resource_wait);
 808                         kfree(res);
 809                         return;
 810                 }
 811                 p = &res->sibling;
 812         }
 813
 814         write_unlock(&resource_lock);
 815
 816         printk(KERN_WARNING "Trying to free nonexistent resource "
 817                 "<%016llx-%016llx>\n", (unsigned long long)start,
 818                 (unsigned long long)end);
 819 }
 820 EXPORT_SYMBOL(__release_region);
 821
 822 /*
 823  * Managed region resource
 824  */
 825 struct region_devres {
 826         struct resource *parent;
 827         resource_size_t start;
 828         resource_size_t n;
 829 };
 830
 831 static void devm_region_release(struct device *dev, void *res)
 832 {
 833         struct region_devres *this = res;
 834
 835         __release_region(this->parent, this->start, this->n);
 836 }
 837
 838 static int devm_region_match(struct device *dev, void *res, void *match_data)
 839 {
 840         struct region_devres *this = res, *match = match_data;
 841
 842         return this->parent == match->parent &&
 843                 this->start == match->start && this->n == match->n;
 844 }
 845
 846 struct resource * __devm_request_region(struct device *dev,
 847                                 struct resource *parent, resource_size_t start,
 848                                 resource_size_t n, const char *name)
 849 {
 850         struct region_devres *dr = NULL;
 851         struct resource *res;
 852
 853         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 854                           GFP_KERNEL);
 855         if (!dr)
 856                 return NULL;
 857
 858         dr->parent = parent;
 859         dr->start = start;
 860         dr->n = n;
 861
 862         res = __request_region(parent, start, n, name, 0);
 863         if (res)
 864                 devres_add(dev, dr);
 865         else
 866                 devres_free(dr);
 867
 868         return res;
 869 }
 870 EXPORT_SYMBOL(__devm_request_region);
 871
 872 void __devm_release_region(struct device *dev, struct resource *parent,
 873                            resource_size_t start, resource_size_t n)
 874 {
 875         struct region_devres match_data = { parent, start, n };
 876
 877         __release_region(parent, start, n);
 878         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
 879                                &match_data));
 880 }
 881 EXPORT_SYMBOL(__devm_release_region);
 882
 883 /*
 884  * Called from init/main.c to reserve IO ports.
 885  */
 886 #define MAXRESERVE 4
 887 static int __init reserve_setup(char *str)
 888 {
 889         static int reserved;
 890         static struct resource reserve[MAXRESERVE];
 891
 892         for (;;) {
 893                 unsigned int io_start, io_num;
 894                 int x = reserved;
 895
 896                 if (get_option (&str, &io_start) != 2)
 897                         break;
 898                 if (get_option (&str, &io_num)   == 0)
 899                         break;
 900                 if (x < MAXRESERVE) {
 901                         struct resource *res = reserve + x;
 902                         res->name = "reserved";
 903                         res->start = io_start;
 904                         res->end = io_start + io_num - 1;
 905                         res->flags = IORESOURCE_BUSY;
 906                         res->child = NULL;
 907                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 908                                 reserved = x+1;
 909                 }
 910         }
 911         return 1;
 912 }
 913
 914 __setup("reserve=", reserve_setup);
 915
 916 /*
 917  * Check if the requested addr and size spans more than any slot in the
 918  * iomem resource tree.
 919  */
 920 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
 921 {
 922         struct resource *p = &iomem_resource;
 923         int err = 0;
 924         loff_t l;
 925
 926         read_lock(&resource_lock);
 927         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 928                 /*
 929                  * We can probably skip the resources without
 930                  * IORESOURCE_IO attribute?
 931                  */
 932                 if (p->start >= addr + size)
 933                         continue;
 934                 if (p->end < addr)
 935                         continue;
 936                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
 937                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
 938                         continue;
 939                 /*
 940                  * if a resource is "BUSY", it's not a hardware resource
 941                  * but a driver mapping of such a resource; we don't want
 942                  * to warn for those; some drivers legitimately map only
 943                  * partial hardware resources. (example: vesafb)
 944                  */
 945                 if (p->flags & IORESOURCE_BUSY)
 946                         continue;
 947
 948                 printk(KERN_WARNING "resource map sanity check conflict: "
 949                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
 950                        (unsigned long long)addr,
 951                        (unsigned long long)(addr + size - 1),
 952                        (unsigned long long)p->start,
 953                        (unsigned long long)p->end,
 954                        p->name);
 955                 err = -1;
 956                 break;
 957         }
 958         read_unlock(&resource_lock);
 959
 960         return err;
 961 }
 962
 963 #ifdef CONFIG_STRICT_DEVMEM
 964 static int strict_iomem_checks = 1;
 965 #else
 966 static int strict_iomem_checks;
 967 #endif
 968
 969 /*
 970  * check if an address is reserved in the iomem resource tree
 971  * returns 1 if reserved, 0 if not reserved.
 972  */
 973 int iomem_is_exclusive(u64 addr)
 974 {
 975         struct resource *p = &iomem_resource;
 976         int err = 0;
 977         loff_t l;
 978         int size = PAGE_SIZE;
 979
 980         if (!strict_iomem_checks)
 981                 return 0;
 982
 983         addr = addr & PAGE_MASK;
 984
 985         read_lock(&resource_lock);
 986         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 987                 /*
 988                  * We can probably skip the resources without
 989                  * IORESOURCE_IO attribute?
 990                  */
 991                 if (p->start >= addr + size)
 992                         break;
 993                 if (p->end < addr)
 994                         continue;
 995                 if (p->flags & IORESOURCE_BUSY &&
 996                      p->flags & IORESOURCE_EXCLUSIVE) {
 997                         err = 1;
 998                         break;
 999                 }
1000         }
1001         read_unlock(&resource_lock);
1002
1003         return err;
1004 }
1005
1006 static int __init strict_iomem(char *str)
1007 {
1008         if (strstr(str, "relaxed"))
1009                 strict_iomem_checks = 0;
1010         if (strstr(str, "strict"))
1011                 strict_iomem_checks = 1;
1012         return 1;
1013 }
1014
1015 __setup("iomem=", strict_iomem);