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 /*
  44  * By default, we allocate free space bottom-up.  The architecture can request
  45  * top-down by clearing this flag.  The user can override the architecture's
  46  * choice with the "resource_alloc_from_bottom" kernel boot option, but that
  47  * should only be a debugging tool.
  48  */
  49 int resource_alloc_from_bottom = 1;
  50
  51 static __init int setup_alloc_from_bottom(char *s)
  52 {
  53         printk(KERN_INFO
  54                "resource: allocating from bottom-up; please report a bug\n");
  55         resource_alloc_from_bottom = 1;
  56         return 0;
  57 }
  58 early_param("resource_alloc_from_bottom", setup_alloc_from_bottom);
  59
  60 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  61 {
  62         struct resource *p = v;
  63         (*pos)++;
  64         if (p->child)
  65                 return p->child;
  66         while (!p->sibling && p->parent)
  67                 p = p->parent;
  68         return p->sibling;
  69 }
  70
  71 #ifdef CONFIG_PROC_FS
  72
  73 enum { MAX_IORES_LEVEL = 5 };
  74
  75 static void *r_start(struct seq_file *m, loff_t *pos)
  76         __acquires(resource_lock)
  77 {
  78         struct resource *p = m->private;
  79         loff_t l = 0;
  80         read_lock(&resource_lock);
  81         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  82                 ;
  83         return p;
  84 }
  85
  86 static void r_stop(struct seq_file *m, void *v)
  87         __releases(resource_lock)
  88 {
  89         read_unlock(&resource_lock);
  90 }
  91
  92 static int r_show(struct seq_file *m, void *v)
  93 {
  94         struct resource *root = m->private;
  95         struct resource *r = v, *p;
  96         int width = root->end < 0x10000 ? 4 : 8;
  97         int depth;
  98
  99         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
 100                 if (p->parent == root)
 101                         break;
 102         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
 103                         depth * 2, "",
 104                         width, (unsigned long long) r->start,
 105                         width, (unsigned long long) r->end,
 106                         r->name ? r->name : "<BAD>");
 107         return 0;
 108 }
 109
 110 static const struct seq_operations resource_op = {
 111         .start  = r_start,
 112         .next   = r_next,
 113         .stop   = r_stop,
 114         .show   = r_show,
 115 };
 116
 117 static int ioports_open(struct inode *inode, struct file *file)
 118 {
 119         int res = seq_open(file, &resource_op);
 120         if (!res) {
 121                 struct seq_file *m = file->private_data;
 122                 m->private = &ioport_resource;
 123         }
 124         return res;
 125 }
 126
 127 static int iomem_open(struct inode *inode, struct file *file)
 128 {
 129         int res = seq_open(file, &resource_op);
 130         if (!res) {
 131                 struct seq_file *m = file->private_data;
 132                 m->private = &iomem_resource;
 133         }
 134         return res;
 135 }
 136
 137 static const struct file_operations proc_ioports_operations = {
 138         .open           = ioports_open,
 139         .read           = seq_read,
 140         .llseek         = seq_lseek,
 141         .release        = seq_release,
 142 };
 143
 144 static const struct file_operations proc_iomem_operations = {
 145         .open           = iomem_open,
 146         .read           = seq_read,
 147         .llseek         = seq_lseek,
 148         .release        = seq_release,
 149 };
 150
 151 static int __init ioresources_init(void)
 152 {
 153         proc_create("ioports", 0, NULL, &proc_ioports_operations);
 154         proc_create("iomem", 0, NULL, &proc_iomem_operations);
 155         return 0;
 156 }
 157 __initcall(ioresources_init);
 158
 159 #endif /* CONFIG_PROC_FS */
 160
 161 /* Return the conflict entry if you can't request it */
 162 static struct resource * __request_resource(struct resource *root, struct resource *new)
 163 {
 164         resource_size_t start = new->start;
 165         resource_size_t end = new->end;
 166         struct resource *tmp, **p;
 167
 168         if (end < start)
 169                 return root;
 170         if (start < root->start)
 171                 return root;
 172         if (end > root->end)
 173                 return root;
 174         p = &root->child;
 175         for (;;) {
 176                 tmp = *p;
 177                 if (!tmp || tmp->start > end) {
 178                         new->sibling = tmp;
 179                         *p = new;
 180                         new->parent = root;
 181                         return NULL;
 182                 }
 183                 p = &tmp->sibling;
 184                 if (tmp->end < start)
 185                         continue;
 186                 return tmp;
 187         }
 188 }
 189
 190 static int __release_resource(struct resource *old)
 191 {
 192         struct resource *tmp, **p;
 193
 194         p = &old->parent->child;
 195         for (;;) {
 196                 tmp = *p;
 197                 if (!tmp)
 198                         break;
 199                 if (tmp == old) {
 200                         *p = tmp->sibling;
 201                         old->parent = NULL;
 202                         return 0;
 203                 }
 204                 p = &tmp->sibling;
 205         }
 206         return -EINVAL;
 207 }
 208
 209 static void __release_child_resources(struct resource *r)
 210 {
 211         struct resource *tmp, *p;
 212         resource_size_t size;
 213
 214         p = r->child;
 215         r->child = NULL;
 216         while (p) {
 217                 tmp = p;
 218                 p = p->sibling;
 219
 220                 tmp->parent = NULL;
 221                 tmp->sibling = NULL;
 222                 __release_child_resources(tmp);
 223
 224                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
 225                 /* need to restore size, and keep flags */
 226                 size = resource_size(tmp);
 227                 tmp->start = 0;
 228                 tmp->end = size - 1;
 229         }
 230 }
 231
 232 void release_child_resources(struct resource *r)
 233 {
 234         write_lock(&resource_lock);
 235         __release_child_resources(r);
 236         write_unlock(&resource_lock);
 237 }
 238
 239 /**
 240  * request_resource_conflict - 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, conflict resource on error.
 245  */
 246 struct resource *request_resource_conflict(struct resource *root, struct resource *new)
 247 {
 248         struct resource *conflict;
 249
 250         write_lock(&resource_lock);
 251         conflict = __request_resource(root, new);
 252         write_unlock(&resource_lock);
 253         return conflict;
 254 }
 255
 256 /**
 257  * request_resource - request and reserve an I/O or memory resource
 258  * @root: root resource descriptor
 259  * @new: resource descriptor desired by caller
 260  *
 261  * Returns 0 for success, negative error code on error.
 262  */
 263 int request_resource(struct resource *root, struct resource *new)
 264 {
 265         struct resource *conflict;
 266
 267         conflict = request_resource_conflict(root, new);
 268         return conflict ? -EBUSY : 0;
 269 }
 270
 271 EXPORT_SYMBOL(request_resource);
 272
 273 /**
 274  * release_resource - release a previously reserved resource
 275  * @old: resource pointer
 276  */
 277 int release_resource(struct resource *old)
 278 {
 279         int retval;
 280
 281         write_lock(&resource_lock);
 282         retval = __release_resource(old);
 283         write_unlock(&resource_lock);
 284         return retval;
 285 }
 286
 287 EXPORT_SYMBOL(release_resource);
 288
 289 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 290 /*
 291  * Finds the lowest memory reosurce exists within [res->start.res->end)
 292  * the caller must specify res->start, res->end, res->flags and "name".
 293  * If found, returns 0, res is overwritten, if not found, returns -1.
 294  */
 295 static int find_next_system_ram(struct resource *res, char *name)
 296 {
 297         resource_size_t start, end;
 298         struct resource *p;
 299
 300         BUG_ON(!res);
 301
 302         start = res->start;
 303         end = res->end;
 304         BUG_ON(start >= end);
 305
 306         read_lock(&resource_lock);
 307         for (p = iomem_resource.child; p ; p = p->sibling) {
 308                 /* system ram is just marked as IORESOURCE_MEM */
 309                 if (p->flags != res->flags)
 310                         continue;
 311                 if (name && strcmp(p->name, name))
 312                         continue;
 313                 if (p->start > end) {
 314                         p = NULL;
 315                         break;
 316                 }
 317                 if ((p->end >= start) && (p->start < end))
 318                         break;
 319         }
 320         read_unlock(&resource_lock);
 321         if (!p)
 322                 return -1;
 323         /* copy data */
 324         if (res->start < p->start)
 325                 res->start = p->start;
 326         if (res->end > p->end)
 327                 res->end = p->end;
 328         return 0;
 329 }
 330
 331 /*
 332  * This function calls callback against all memory range of "System RAM"
 333  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 334  * Now, this function is only for "System RAM".
 335  */
 336 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 337                 void *arg, int (*func)(unsigned long, unsigned long, void *))
 338 {
 339         struct resource res;
 340         unsigned long pfn, end_pfn;
 341         u64 orig_end;
 342         int ret = -1;
 343
 344         res.start = (u64) start_pfn << PAGE_SHIFT;
 345         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 346         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 347         orig_end = res.end;
 348         while ((res.start < res.end) &&
 349                 (find_next_system_ram(&res, "System RAM") >= 0)) {
 350                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 351                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
 352                 if (end_pfn > pfn)
 353                         ret = (*func)(pfn, end_pfn - pfn, arg);
 354                 if (ret)
 355                         break;
 356                 res.start = res.end + 1;
 357                 res.end = orig_end;
 358         }
 359         return ret;
 360 }
 361
 362 #endif
 363
 364 static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
 365 {
 366         return 1;
 367 }
 368 /*
 369  * This generic page_is_ram() returns true if specified address is
 370  * registered as "System RAM" in iomem_resource list.
 371  */
 372 int __weak page_is_ram(unsigned long pfn)
 373 {
 374         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 375 }
 376
 377 static resource_size_t simple_align_resource(void *data,
 378                                              const struct resource *avail,
 379                                              resource_size_t size,
 380                                              resource_size_t align)
 381 {
 382         return avail->start;
 383 }
 384
 385 static void resource_clip(struct resource *res, resource_size_t min,
 386                           resource_size_t max)
 387 {
 388         if (res->start < min)
 389                 res->start = min;
 390         if (res->end > max)
 391                 res->end = max;
 392 }
 393
 394 static bool resource_contains(struct resource *res1, struct resource *res2)
 395 {
 396         return res1->start <= res2->start && res1->end >= res2->end;
 397 }
 398
 399 /*
 400  * Find the resource before "child" in the sibling list of "root" children.
 401  */
 402 static struct resource *find_sibling_prev(struct resource *root, struct resource *child)
 403 {
 404         struct resource *this;
 405
 406         for (this = root->child; this; this = this->sibling)
 407                 if (this->sibling == child)
 408                         return this;
 409
 410         return NULL;
 411 }
 412
 413 /*
 414  * Find empty slot in the resource tree given range and alignment.
 415  * This version allocates from the end of the root resource first.
 416  */
 417 static int find_resource_from_top(struct resource *root, struct resource *new,
 418                                   resource_size_t size, resource_size_t min,
 419                                   resource_size_t max, resource_size_t align,
 420                                   resource_size_t (*alignf)(void *,
 421                                                    const struct resource *,
 422                                                    resource_size_t,
 423                                                    resource_size_t),
 424                                   void *alignf_data)
 425 {
 426         struct resource *this;
 427         struct resource tmp, avail, alloc;
 428
 429         tmp.start = root->end;
 430         tmp.end = root->end;
 431
 432         this = find_sibling_prev(root, NULL);
 433         for (;;) {
 434                 if (this) {
 435                         if (this->end < root->end)
 436                                 tmp.start = this->end + 1;
 437                 } else
 438                         tmp.start = root->start;
 439
 440                 resource_clip(&tmp, min, max);
 441
 442                 /* Check for overflow after ALIGN() */
 443                 avail = *new;
 444                 avail.start = ALIGN(tmp.start, align);
 445                 avail.end = tmp.end;
 446                 if (avail.start >= tmp.start) {
 447                         alloc.start = alignf(alignf_data, &avail, size, align);
 448                         alloc.end = alloc.start + size - 1;
 449                         if (resource_contains(&avail, &alloc)) {
 450                                 new->start = alloc.start;
 451                                 new->end = alloc.end;
 452                                 return 0;
 453                         }
 454                 }
 455
 456                 if (!this || this->start == root->start)
 457                         break;
 458
 459                 tmp.end = this->start - 1;
 460                 this = find_sibling_prev(root, this);
 461         }
 462         return -EBUSY;
 463 }
 464
 465 /*
 466  * Find empty slot in the resource tree given range and alignment.
 467  * This version allocates from the beginning of the root resource first.
 468  */
 469 static int find_resource(struct resource *root, struct resource *new,
 470                          resource_size_t size, resource_size_t min,
 471                          resource_size_t max, resource_size_t align,
 472                          resource_size_t (*alignf)(void *,
 473                                                    const struct resource *,
 474                                                    resource_size_t,
 475                                                    resource_size_t),
 476                          void *alignf_data)
 477 {
 478         struct resource *this = root->child;
 479         struct resource tmp = *new, avail, alloc;
 480
 481         tmp.start = root->start;
 482         /*
 483          * Skip past an allocated resource that starts at 0, since the
 484          * assignment of this->start - 1 to tmp->end below would cause an
 485          * underflow.
 486          */
 487         if (this && this->start == 0) {
 488                 tmp.start = this->end + 1;
 489                 this = this->sibling;
 490         }
 491         for (;;) {
 492                 if (this)
 493                         tmp.end = this->start - 1;
 494                 else
 495                         tmp.end = root->end;
 496
 497                 resource_clip(&tmp, min, max);
 498
 499                 /* Check for overflow after ALIGN() */
 500                 avail = *new;
 501                 avail.start = ALIGN(tmp.start, align);
 502                 avail.end = tmp.end;
 503                 if (avail.start >= tmp.start) {
 504                         alloc.start = alignf(alignf_data, &avail, size, align);
 505                         alloc.end = alloc.start + size - 1;
 506                         if (resource_contains(&avail, &alloc)) {
 507                                 new->start = alloc.start;
 508                                 new->end = alloc.end;
 509                                 return 0;
 510                         }
 511                 }
 512
 513                 if (!this)
 514                         break;
 515
 516                 tmp.start = this->end + 1;
 517                 this = this->sibling;
 518         }
 519         return -EBUSY;
 520 }
 521
 522 /**
 523  * allocate_resource - allocate empty slot in the resource tree given range & alignment
 524  * @root: root resource descriptor
 525  * @new: resource descriptor desired by caller
 526  * @size: requested resource region size
 527  * @min: minimum size to allocate
 528  * @max: maximum size to allocate
 529  * @align: alignment requested, in bytes
 530  * @alignf: alignment function, optional, called if not NULL
 531  * @alignf_data: arbitrary data to pass to the @alignf function
 532  */
 533 int allocate_resource(struct resource *root, struct resource *new,
 534                       resource_size_t size, resource_size_t min,
 535                       resource_size_t max, resource_size_t align,
 536                       resource_size_t (*alignf)(void *,
 537                                                 const struct resource *,
 538                                                 resource_size_t,
 539                                                 resource_size_t),
 540                       void *alignf_data)
 541 {
 542         int err;
 543
 544         if (!alignf)
 545                 alignf = simple_align_resource;
 546
 547         write_lock(&resource_lock);
 548         if (resource_alloc_from_bottom)
 549                 err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 550         else
 551                 err = find_resource_from_top(root, new, size, min, max, align, alignf, alignf_data);
 552         if (err >= 0 && __request_resource(root, new))
 553                 err = -EBUSY;
 554         write_unlock(&resource_lock);
 555         return err;
 556 }
 557
 558 EXPORT_SYMBOL(allocate_resource);
 559
 560 /*
 561  * Insert a resource into the resource tree. If successful, return NULL,
 562  * otherwise return the conflicting resource (compare to __request_resource())
 563  */
 564 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 565 {
 566         struct resource *first, *next;
 567
 568         for (;; parent = first) {
 569                 first = __request_resource(parent, new);
 570                 if (!first)
 571                         return first;
 572
 573                 if (first == parent)
 574                         return first;
 575                 if (WARN_ON(first == new))      /* duplicated insertion */
 576                         return first;
 577
 578                 if ((first->start > new->start) || (first->end < new->end))
 579                         break;
 580                 if ((first->start == new->start) && (first->end == new->end))
 581                         break;
 582         }
 583
 584         for (next = first; ; next = next->sibling) {
 585                 /* Partial overlap? Bad, and unfixable */
 586                 if (next->start < new->start || next->end > new->end)
 587                         return next;
 588                 if (!next->sibling)
 589                         break;
 590                 if (next->sibling->start > new->end)
 591                         break;
 592         }
 593
 594         new->parent = parent;
 595         new->sibling = next->sibling;
 596         new->child = first;
 597
 598         next->sibling = NULL;
 599         for (next = first; next; next = next->sibling)
 600                 next->parent = new;
 601
 602         if (parent->child == first) {
 603                 parent->child = new;
 604         } else {
 605                 next = parent->child;
 606                 while (next->sibling != first)
 607                         next = next->sibling;
 608                 next->sibling = new;
 609         }
 610         return NULL;
 611 }
 612
 613 /**
 614  * insert_resource_conflict - Inserts resource in the resource tree
 615  * @parent: parent of the new resource
 616  * @new: new resource to insert
 617  *
 618  * Returns 0 on success, conflict resource if the resource can't be inserted.
 619  *
 620  * This function is equivalent to request_resource_conflict when no conflict
 621  * happens. If a conflict happens, and the conflicting resources
 622  * entirely fit within the range of the new resource, then the new
 623  * resource is inserted and the conflicting resources become children of
 624  * the new resource.
 625  */
 626 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 627 {
 628         struct resource *conflict;
 629
 630         write_lock(&resource_lock);
 631         conflict = __insert_resource(parent, new);
 632         write_unlock(&resource_lock);
 633         return conflict;
 634 }
 635
 636 /**
 637  * insert_resource - Inserts a resource in the resource tree
 638  * @parent: parent of the new resource
 639  * @new: new resource to insert
 640  *
 641  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 642  */
 643 int insert_resource(struct resource *parent, struct resource *new)
 644 {
 645         struct resource *conflict;
 646
 647         conflict = insert_resource_conflict(parent, new);
 648         return conflict ? -EBUSY : 0;
 649 }
 650
 651 /**
 652  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 653  * @root: root resource descriptor
 654  * @new: new resource to insert
 655  *
 656  * Insert a resource into the resource tree, possibly expanding it in order
 657  * to make it encompass any conflicting resources.
 658  */
 659 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 660 {
 661         if (new->parent)
 662                 return;
 663
 664         write_lock(&resource_lock);
 665         for (;;) {
 666                 struct resource *conflict;
 667
 668                 conflict = __insert_resource(root, new);
 669                 if (!conflict)
 670                         break;
 671                 if (conflict == root)
 672                         break;
 673
 674                 /* Ok, expand resource to cover the conflict, then try again .. */
 675                 if (conflict->start < new->start)
 676                         new->start = conflict->start;
 677                 if (conflict->end > new->end)
 678                         new->end = conflict->end;
 679
 680                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 681         }
 682         write_unlock(&resource_lock);
 683 }
 684
 685 /**
 686  * adjust_resource - modify a resource's start and size
 687  * @res: resource to modify
 688  * @start: new start value
 689  * @size: new size
 690  *
 691  * Given an existing resource, change its start and size to match the
 692  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 693  * Existing children of the resource are assumed to be immutable.
 694  */
 695 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 696 {
 697         struct resource *tmp, *parent = res->parent;
 698         resource_size_t end = start + size - 1;
 699         int result = -EBUSY;
 700
 701         write_lock(&resource_lock);
 702
 703         if ((start < parent->start) || (end > parent->end))
 704                 goto out;
 705
 706         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 707                 if ((tmp->start < start) || (tmp->end > end))
 708                         goto out;
 709         }
 710
 711         if (res->sibling && (res->sibling->start <= end))
 712                 goto out;
 713
 714         tmp = parent->child;
 715         if (tmp != res) {
 716                 while (tmp->sibling != res)
 717                         tmp = tmp->sibling;
 718                 if (start <= tmp->end)
 719                         goto out;
 720         }
 721
 722         res->start = start;
 723         res->end = end;
 724         result = 0;
 725
 726  out:
 727         write_unlock(&resource_lock);
 728         return result;
 729 }
 730
 731 static void __init __reserve_region_with_split(struct resource *root,
 732                 resource_size_t start, resource_size_t end,
 733                 const char *name)
 734 {
 735         struct resource *parent = root;
 736         struct resource *conflict;
 737         struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
 738
 739         if (!res)
 740                 return;
 741
 742         res->name = name;
 743         res->start = start;
 744         res->end = end;
 745         res->flags = IORESOURCE_BUSY;
 746
 747         conflict = __request_resource(parent, res);
 748         if (!conflict)
 749                 return;
 750
 751         /* failed, split and try again */
 752         kfree(res);
 753
 754         /* conflict covered whole area */
 755         if (conflict->start <= start && conflict->end >= end)
 756                 return;
 757
 758         if (conflict->start > start)
 759                 __reserve_region_with_split(root, start, conflict->start-1, name);
 760         if (conflict->end < end)
 761                 __reserve_region_with_split(root, conflict->end+1, end, name);
 762 }
 763
 764 void __init reserve_region_with_split(struct resource *root,
 765                 resource_size_t start, resource_size_t end,
 766                 const char *name)
 767 {
 768         write_lock(&resource_lock);
 769         __reserve_region_with_split(root, start, end, name);
 770         write_unlock(&resource_lock);
 771 }
 772
 773 EXPORT_SYMBOL(adjust_resource);
 774
 775 /**
 776  * resource_alignment - calculate resource's alignment
 777  * @res: resource pointer
 778  *
 779  * Returns alignment on success, 0 (invalid alignment) on failure.
 780  */
 781 resource_size_t resource_alignment(struct resource *res)
 782 {
 783         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 784         case IORESOURCE_SIZEALIGN:
 785                 return resource_size(res);
 786         case IORESOURCE_STARTALIGN:
 787                 return res->start;
 788         default:
 789                 return 0;
 790         }
 791 }
 792
 793 /*
 794  * This is compatibility stuff for IO resources.
 795  *
 796  * Note how this, unlike the above, knows about
 797  * the IO flag meanings (busy etc).
 798  *
 799  * request_region creates a new busy region.
 800  *
 801  * check_region returns non-zero if the area is already busy.
 802  *
 803  * release_region releases a matching busy region.
 804  */
 805
 806 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
 807
 808 /**
 809  * __request_region - create a new busy resource region
 810  * @parent: parent resource descriptor
 811  * @start: resource start address
 812  * @n: resource region size
 813  * @name: reserving caller's ID string
 814  * @flags: IO resource flags
 815  */
 816 struct resource * __request_region(struct resource *parent,
 817                                    resource_size_t start, resource_size_t n,
 818                                    const char *name, int flags)
 819 {
 820         DECLARE_WAITQUEUE(wait, current);
 821         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 822
 823         if (!res)
 824                 return NULL;
 825
 826         res->name = name;
 827         res->start = start;
 828         res->end = start + n - 1;
 829         res->flags = IORESOURCE_BUSY;
 830         res->flags |= flags;
 831
 832         write_lock(&resource_lock);
 833
 834         for (;;) {
 835                 struct resource *conflict;
 836
 837                 conflict = __request_resource(parent, res);
 838                 if (!conflict)
 839                         break;
 840                 if (conflict != parent) {
 841                         parent = conflict;
 842                         if (!(conflict->flags & IORESOURCE_BUSY))
 843                                 continue;
 844                 }
 845                 if (conflict->flags & flags & IORESOURCE_MUXED) {
 846                         add_wait_queue(&muxed_resource_wait, &wait);
 847                         write_unlock(&resource_lock);
 848                         set_current_state(TASK_UNINTERRUPTIBLE);
 849                         schedule();
 850                         remove_wait_queue(&muxed_resource_wait, &wait);
 851                         write_lock(&resource_lock);
 852                         continue;
 853                 }
 854                 /* Uhhuh, that didn't work out.. */
 855                 kfree(res);
 856                 res = NULL;
 857                 break;
 858         }
 859         write_unlock(&resource_lock);
 860         return res;
 861 }
 862 EXPORT_SYMBOL(__request_region);
 863
 864 /**
 865  * __check_region - check if a resource region is busy or free
 866  * @parent: parent resource descriptor
 867  * @start: resource start address
 868  * @n: resource region size
 869  *
 870  * Returns 0 if the region is free at the moment it is checked,
 871  * returns %-EBUSY if the region is busy.
 872  *
 873  * NOTE:
 874  * This function is deprecated because its use is racy.
 875  * Even if it returns 0, a subsequent call to request_region()
 876  * may fail because another driver etc. just allocated the region.
 877  * Do NOT use it.  It will be removed from the kernel.
 878  */
 879 int __check_region(struct resource *parent, resource_size_t start,
 880                         resource_size_t n)
 881 {
 882         struct resource * res;
 883
 884         res = __request_region(parent, start, n, "check-region", 0);
 885         if (!res)
 886                 return -EBUSY;
 887
 888         release_resource(res);
 889         kfree(res);
 890         return 0;
 891 }
 892 EXPORT_SYMBOL(__check_region);
 893
 894 /**
 895  * __release_region - release a previously reserved resource region
 896  * @parent: parent resource descriptor
 897  * @start: resource start address
 898  * @n: resource region size
 899  *
 900  * The described resource region must match a currently busy region.
 901  */
 902 void __release_region(struct resource *parent, resource_size_t start,
 903                         resource_size_t n)
 904 {
 905         struct resource **p;
 906         resource_size_t end;
 907
 908         p = &parent->child;
 909         end = start + n - 1;
 910
 911         write_lock(&resource_lock);
 912
 913         for (;;) {
 914                 struct resource *res = *p;
 915
 916                 if (!res)
 917                         break;
 918                 if (res->start <= start && res->end >= end) {
 919                         if (!(res->flags & IORESOURCE_BUSY)) {
 920                                 p = &res->child;
 921                                 continue;
 922                         }
 923                         if (res->start != start || res->end != end)
 924                                 break;
 925                         *p = res->sibling;
 926                         write_unlock(&resource_lock);
 927                         if (res->flags & IORESOURCE_MUXED)
 928                                 wake_up(&muxed_resource_wait);
 929                         kfree(res);
 930                         return;
 931                 }
 932                 p = &res->sibling;
 933         }
 934
 935         write_unlock(&resource_lock);
 936
 937         printk(KERN_WARNING "Trying to free nonexistent resource "
 938                 "<%016llx-%016llx>\n", (unsigned long long)start,
 939                 (unsigned long long)end);
 940 }
 941 EXPORT_SYMBOL(__release_region);
 942
 943 /*
 944  * Managed region resource
 945  */
 946 struct region_devres {
 947         struct resource *parent;
 948         resource_size_t start;
 949         resource_size_t n;
 950 };
 951
 952 static void devm_region_release(struct device *dev, void *res)
 953 {
 954         struct region_devres *this = res;
 955
 956         __release_region(this->parent, this->start, this->n);
 957 }
 958
 959 static int devm_region_match(struct device *dev, void *res, void *match_data)
 960 {
 961         struct region_devres *this = res, *match = match_data;
 962
 963         return this->parent == match->parent &&
 964                 this->start == match->start && this->n == match->n;
 965 }
 966
 967 struct resource * __devm_request_region(struct device *dev,
 968                                 struct resource *parent, resource_size_t start,
 969                                 resource_size_t n, const char *name)
 970 {
 971         struct region_devres *dr = NULL;
 972         struct resource *res;
 973
 974         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 975                           GFP_KERNEL);
 976         if (!dr)
 977                 return NULL;
 978
 979         dr->parent = parent;
 980         dr->start = start;
 981         dr->n = n;
 982
 983         res = __request_region(parent, start, n, name, 0);
 984         if (res)
 985                 devres_add(dev, dr);
 986         else
 987                 devres_free(dr);
 988
 989         return res;
 990 }
 991 EXPORT_SYMBOL(__devm_request_region);
 992
 993 void __devm_release_region(struct device *dev, struct resource *parent,
 994                            resource_size_t start, resource_size_t n)
 995 {
 996         struct region_devres match_data = { parent, start, n };
 997
 998         __release_region(parent, start, n);
 999         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1000                                &match_data));
1001 }
1002 EXPORT_SYMBOL(__devm_release_region);
1003
1004 /*
1005  * Called from init/main.c to reserve IO ports.
1006  */
1007 #define MAXRESERVE 4
1008 static int __init reserve_setup(char *str)
1009 {
1010         static int reserved;
1011         static struct resource reserve[MAXRESERVE];
1012
1013         for (;;) {
1014                 unsigned int io_start, io_num;
1015                 int x = reserved;
1016
1017                 if (get_option (&str, &io_start) != 2)
1018                         break;
1019                 if (get_option (&str, &io_num)   == 0)
1020                         break;
1021                 if (x < MAXRESERVE) {
1022                         struct resource *res = reserve + x;
1023                         res->name = "reserved";
1024                         res->start = io_start;
1025                         res->end = io_start + io_num - 1;
1026                         res->flags = IORESOURCE_BUSY;
1027                         res->child = NULL;
1028                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1029                                 reserved = x+1;
1030                 }
1031         }
1032         return 1;
1033 }
1034
1035 __setup("reserve=", reserve_setup);
1036
1037 /*
1038  * Check if the requested addr and size spans more than any slot in the
1039  * iomem resource tree.
1040  */
1041 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1042 {
1043         struct resource *p = &iomem_resource;
1044         int err = 0;
1045         loff_t l;
1046
1047         read_lock(&resource_lock);
1048         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1049                 /*
1050                  * We can probably skip the resources without
1051                  * IORESOURCE_IO attribute?
1052                  */
1053                 if (p->start >= addr + size)
1054                         continue;
1055                 if (p->end < addr)
1056                         continue;
1057                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1058                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1059                         continue;
1060                 /*
1061                  * if a resource is "BUSY", it's not a hardware resource
1062                  * but a driver mapping of such a resource; we don't want
1063                  * to warn for those; some drivers legitimately map only
1064                  * partial hardware resources. (example: vesafb)
1065                  */
1066                 if (p->flags & IORESOURCE_BUSY)
1067                         continue;
1068
1069                 printk(KERN_WARNING "resource map sanity check conflict: "
1070                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
1071                        (unsigned long long)addr,
1072                        (unsigned long long)(addr + size - 1),
1073                        (unsigned long long)p->start,
1074                        (unsigned long long)p->end,
1075                        p->name);
1076                 err = -1;
1077                 break;
1078         }
1079         read_unlock(&resource_lock);
1080
1081         return err;
1082 }
1083
1084 #ifdef CONFIG_STRICT_DEVMEM
1085 static int strict_iomem_checks = 1;
1086 #else
1087 static int strict_iomem_checks;
1088 #endif
1089
1090 /*
1091  * check if an address is reserved in the iomem resource tree
1092  * returns 1 if reserved, 0 if not reserved.
1093  */
1094 int iomem_is_exclusive(u64 addr)
1095 {
1096         struct resource *p = &iomem_resource;
1097         int err = 0;
1098         loff_t l;
1099         int size = PAGE_SIZE;
1100
1101         if (!strict_iomem_checks)
1102                 return 0;
1103
1104         addr = addr & PAGE_MASK;
1105
1106         read_lock(&resource_lock);
1107         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1108                 /*
1109                  * We can probably skip the resources without
1110                  * IORESOURCE_IO attribute?
1111                  */
1112                 if (p->start >= addr + size)
1113                         break;
1114                 if (p->end < addr)
1115                         continue;
1116                 if (p->flags & IORESOURCE_BUSY &&
1117                      p->flags & IORESOURCE_EXCLUSIVE) {
1118                         err = 1;
1119                         break;
1120                 }
1121         }
1122         read_unlock(&resource_lock);
1123
1124         return err;
1125 }
1126
1127 static int __init strict_iomem(char *str)
1128 {
1129         if (strstr(str, "relaxed"))
1130                 strict_iomem_checks = 0;
1131         if (strstr(str, "strict"))
1132                 strict_iomem_checks = 1;
1133         return 1;
1134 }
1135
1136 __setup("iomem=", strict_iomem);