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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/export.h>
  13 #include <linux/errno.h>
  14 #include <linux/ioport.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/fs.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/sched.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/device.h>
  23 #include <linux/pfn.h>
  24 #include <linux/mm.h>
  25 #include <asm/io.h>
  26
  27
  28 struct resource ioport_resource = {
  29         .name   = "PCI IO",
  30         .start  = 0,
  31         .end    = IO_SPACE_LIMIT,
  32         .flags  = IORESOURCE_IO,
  33 };
  34 EXPORT_SYMBOL(ioport_resource);
  35
  36 struct resource iomem_resource = {
  37         .name   = "PCI mem",
  38         .start  = 0,
  39         .end    = -1,
  40         .flags  = IORESOURCE_MEM,
  41 };
  42 EXPORT_SYMBOL(iomem_resource);
  43
  44 /* constraints to be met while allocating resources */
  45 struct resource_constraint {
  46         resource_size_t min, max, align;
  47         resource_size_t (*alignf)(void *, const struct resource *,
  48                         resource_size_t, resource_size_t);
  49         void *alignf_data;
  50 };
  51
  52 static DEFINE_RWLOCK(resource_lock);
  53
  54 /*
  55  * For memory hotplug, there is no way to free resource entries allocated
  56  * by boot mem after the system is up. So for reusing the resource entry
  57  * we need to remember the resource.
  58  */
  59 static struct resource *bootmem_resource_free;
  60 static DEFINE_SPINLOCK(bootmem_resource_lock);
  61
  62 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  63 {
  64         struct resource *p = v;
  65         (*pos)++;
  66         if (p->child)
  67                 return p->child;
  68         while (!p->sibling && p->parent)
  69                 p = p->parent;
  70         return p->sibling;
  71 }
  72
  73 #ifdef CONFIG_PROC_FS
  74
  75 enum { MAX_IORES_LEVEL = 5 };
  76
  77 static void *r_start(struct seq_file *m, loff_t *pos)
  78         __acquires(resource_lock)
  79 {
  80         struct resource *p = m->private;
  81         loff_t l = 0;
  82         read_lock(&resource_lock);
  83         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  84                 ;
  85         return p;
  86 }
  87
  88 static void r_stop(struct seq_file *m, void *v)
  89         __releases(resource_lock)
  90 {
  91         read_unlock(&resource_lock);
  92 }
  93
  94 static int r_show(struct seq_file *m, void *v)
  95 {
  96         struct resource *root = m->private;
  97         struct resource *r = v, *p;
  98         int width = root->end < 0x10000 ? 4 : 8;
  99         int depth;
 100
 101         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
 102                 if (p->parent == root)
 103                         break;
 104         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
 105                         depth * 2, "",
 106                         width, (unsigned long long) r->start,
 107                         width, (unsigned long long) r->end,
 108                         r->name ? r->name : "<BAD>");
 109         return 0;
 110 }
 111
 112 static const struct seq_operations resource_op = {
 113         .start  = r_start,
 114         .next   = r_next,
 115         .stop   = r_stop,
 116         .show   = r_show,
 117 };
 118
 119 static int ioports_open(struct inode *inode, struct file *file)
 120 {
 121         int res = seq_open(file, &resource_op);
 122         if (!res) {
 123                 struct seq_file *m = file->private_data;
 124                 m->private = &ioport_resource;
 125         }
 126         return res;
 127 }
 128
 129 static int iomem_open(struct inode *inode, struct file *file)
 130 {
 131         int res = seq_open(file, &resource_op);
 132         if (!res) {
 133                 struct seq_file *m = file->private_data;
 134                 m->private = &iomem_resource;
 135         }
 136         return res;
 137 }
 138
 139 static const struct file_operations proc_ioports_operations = {
 140         .open           = ioports_open,
 141         .read           = seq_read,
 142         .llseek         = seq_lseek,
 143         .release        = seq_release,
 144 };
 145
 146 static const struct file_operations proc_iomem_operations = {
 147         .open           = iomem_open,
 148         .read           = seq_read,
 149         .llseek         = seq_lseek,
 150         .release        = seq_release,
 151 };
 152
 153 static int __init ioresources_init(void)
 154 {
 155         proc_create("ioports", 0, NULL, &proc_ioports_operations);
 156         proc_create("iomem", 0, NULL, &proc_iomem_operations);
 157         return 0;
 158 }
 159 __initcall(ioresources_init);
 160
 161 #endif /* CONFIG_PROC_FS */
 162
 163 static void free_resource(struct resource *res)
 164 {
 165         if (!res)
 166                 return;
 167
 168         if (!PageSlab(virt_to_head_page(res))) {
 169                 spin_lock(&bootmem_resource_lock);
 170                 res->sibling = bootmem_resource_free;
 171                 bootmem_resource_free = res;
 172                 spin_unlock(&bootmem_resource_lock);
 173         } else {
 174                 kfree(res);
 175         }
 176 }
 177
 178 static struct resource *alloc_resource(gfp_t flags)
 179 {
 180         struct resource *res = NULL;
 181
 182         spin_lock(&bootmem_resource_lock);
 183         if (bootmem_resource_free) {
 184                 res = bootmem_resource_free;
 185                 bootmem_resource_free = res->sibling;
 186         }
 187         spin_unlock(&bootmem_resource_lock);
 188
 189         if (res)
 190                 memset(res, 0, sizeof(struct resource));
 191         else
 192                 res = kzalloc(sizeof(struct resource), flags);
 193
 194         return res;
 195 }
 196
 197 /* Return the conflict entry if you can't request it */
 198 static struct resource * __request_resource(struct resource *root, struct resource *new)
 199 {
 200         resource_size_t start = new->start;
 201         resource_size_t end = new->end;
 202         struct resource *tmp, **p;
 203
 204         if (end < start)
 205                 return root;
 206         if (start < root->start)
 207                 return root;
 208         if (end > root->end)
 209                 return root;
 210         p = &root->child;
 211         for (;;) {
 212                 tmp = *p;
 213                 if (!tmp || tmp->start > end) {
 214                         new->sibling = tmp;
 215                         *p = new;
 216                         new->parent = root;
 217                         return NULL;
 218                 }
 219                 p = &tmp->sibling;
 220                 if (tmp->end < start)
 221                         continue;
 222                 return tmp;
 223         }
 224 }
 225
 226 static int __release_resource(struct resource *old)
 227 {
 228         struct resource *tmp, **p;
 229
 230         p = &old->parent->child;
 231         for (;;) {
 232                 tmp = *p;
 233                 if (!tmp)
 234                         break;
 235                 if (tmp == old) {
 236                         *p = tmp->sibling;
 237                         old->parent = NULL;
 238                         return 0;
 239                 }
 240                 p = &tmp->sibling;
 241         }
 242         return -EINVAL;
 243 }
 244
 245 static void __release_child_resources(struct resource *r)
 246 {
 247         struct resource *tmp, *p;
 248         resource_size_t size;
 249
 250         p = r->child;
 251         r->child = NULL;
 252         while (p) {
 253                 tmp = p;
 254                 p = p->sibling;
 255
 256                 tmp->parent = NULL;
 257                 tmp->sibling = NULL;
 258                 __release_child_resources(tmp);
 259
 260                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
 261                 /* need to restore size, and keep flags */
 262                 size = resource_size(tmp);
 263                 tmp->start = 0;
 264                 tmp->end = size - 1;
 265         }
 266 }
 267
 268 void release_child_resources(struct resource *r)
 269 {
 270         write_lock(&resource_lock);
 271         __release_child_resources(r);
 272         write_unlock(&resource_lock);
 273 }
 274
 275 /**
 276  * request_resource_conflict - request and reserve an I/O or memory resource
 277  * @root: root resource descriptor
 278  * @new: resource descriptor desired by caller
 279  *
 280  * Returns 0 for success, conflict resource on error.
 281  */
 282 struct resource *request_resource_conflict(struct resource *root, struct resource *new)
 283 {
 284         struct resource *conflict;
 285
 286         write_lock(&resource_lock);
 287         conflict = __request_resource(root, new);
 288         write_unlock(&resource_lock);
 289         return conflict;
 290 }
 291
 292 /**
 293  * request_resource - request and reserve an I/O or memory resource
 294  * @root: root resource descriptor
 295  * @new: resource descriptor desired by caller
 296  *
 297  * Returns 0 for success, negative error code on error.
 298  */
 299 int request_resource(struct resource *root, struct resource *new)
 300 {
 301         struct resource *conflict;
 302
 303         conflict = request_resource_conflict(root, new);
 304         return conflict ? -EBUSY : 0;
 305 }
 306
 307 EXPORT_SYMBOL(request_resource);
 308
 309 /**
 310  * release_resource - release a previously reserved resource
 311  * @old: resource pointer
 312  */
 313 int release_resource(struct resource *old)
 314 {
 315         int retval;
 316
 317         write_lock(&resource_lock);
 318         retval = __release_resource(old);
 319         write_unlock(&resource_lock);
 320         return retval;
 321 }
 322
 323 EXPORT_SYMBOL(release_resource);
 324
 325 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 326 /*
 327  * Finds the lowest memory reosurce exists within [res->start.res->end)
 328  * the caller must specify res->start, res->end, res->flags and "name".
 329  * If found, returns 0, res is overwritten, if not found, returns -1.
 330  */
 331 static int find_next_system_ram(struct resource *res, char *name)
 332 {
 333         resource_size_t start, end;
 334         struct resource *p;
 335
 336         BUG_ON(!res);
 337
 338         start = res->start;
 339         end = res->end;
 340         BUG_ON(start >= end);
 341
 342         read_lock(&resource_lock);
 343         for (p = iomem_resource.child; p ; p = p->sibling) {
 344                 /* system ram is just marked as IORESOURCE_MEM */
 345                 if (p->flags != res->flags)
 346                         continue;
 347                 if (name && strcmp(p->name, name))
 348                         continue;
 349                 if (p->start > end) {
 350                         p = NULL;
 351                         break;
 352                 }
 353                 if ((p->end >= start) && (p->start < end))
 354                         break;
 355         }
 356         read_unlock(&resource_lock);
 357         if (!p)
 358                 return -1;
 359         /* copy data */
 360         if (res->start < p->start)
 361                 res->start = p->start;
 362         if (res->end > p->end)
 363                 res->end = p->end;
 364         return 0;
 365 }
 366
 367 /*
 368  * This function calls callback against all memory range of "System RAM"
 369  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 370  * Now, this function is only for "System RAM".
 371  */
 372 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 373                 void *arg, int (*func)(unsigned long, unsigned long, void *))
 374 {
 375         struct resource res;
 376         unsigned long pfn, end_pfn;
 377         u64 orig_end;
 378         int ret = -1;
 379
 380         res.start = (u64) start_pfn << PAGE_SHIFT;
 381         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 382         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 383         orig_end = res.end;
 384         while ((res.start < res.end) &&
 385                 (find_next_system_ram(&res, "System RAM") >= 0)) {
 386                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 387                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
 388                 if (end_pfn > pfn)
 389                         ret = (*func)(pfn, end_pfn - pfn, arg);
 390                 if (ret)
 391                         break;
 392                 res.start = res.end + 1;
 393                 res.end = orig_end;
 394         }
 395         return ret;
 396 }
 397
 398 #endif
 399
 400 static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
 401 {
 402         return 1;
 403 }
 404 /*
 405  * This generic page_is_ram() returns true if specified address is
 406  * registered as "System RAM" in iomem_resource list.
 407  */
 408 int __weak page_is_ram(unsigned long pfn)
 409 {
 410         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 411 }
 412 EXPORT_SYMBOL_GPL(page_is_ram);
 413
 414 void __weak arch_remove_reservations(struct resource *avail)
 415 {
 416 }
 417
 418 static resource_size_t simple_align_resource(void *data,
 419                                              const struct resource *avail,
 420                                              resource_size_t size,
 421                                              resource_size_t align)
 422 {
 423         return avail->start;
 424 }
 425
 426 static void resource_clip(struct resource *res, resource_size_t min,
 427                           resource_size_t max)
 428 {
 429         if (res->start < min)
 430                 res->start = min;
 431         if (res->end > max)
 432                 res->end = max;
 433 }
 434
 435 /*
 436  * Find empty slot in the resource tree with the given range and
 437  * alignment constraints
 438  */
 439 static int __find_resource(struct resource *root, struct resource *old,
 440                          struct resource *new,
 441                          resource_size_t  size,
 442                          struct resource_constraint *constraint)
 443 {
 444         struct resource *this = root->child;
 445         struct resource tmp = *new, avail, alloc;
 446
 447         tmp.start = root->start;
 448         /*
 449          * Skip past an allocated resource that starts at 0, since the assignment
 450          * of this->start - 1 to tmp->end below would cause an underflow.
 451          */
 452         if (this && this->start == root->start) {
 453                 tmp.start = (this == old) ? old->start : this->end + 1;
 454                 this = this->sibling;
 455         }
 456         for(;;) {
 457                 if (this)
 458                         tmp.end = (this == old) ?  this->end : this->start - 1;
 459                 else
 460                         tmp.end = root->end;
 461
 462                 if (tmp.end < tmp.start)
 463                         goto next;
 464
 465                 resource_clip(&tmp, constraint->min, constraint->max);
 466                 arch_remove_reservations(&tmp);
 467
 468                 /* Check for overflow after ALIGN() */
 469                 avail.start = ALIGN(tmp.start, constraint->align);
 470                 avail.end = tmp.end;
 471                 avail.flags = new->flags & ~IORESOURCE_UNSET;
 472                 if (avail.start >= tmp.start) {
 473                         alloc.flags = avail.flags;
 474                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
 475                                         size, constraint->align);
 476                         alloc.end = alloc.start + size - 1;
 477                         if (resource_contains(&avail, &alloc)) {
 478                                 new->start = alloc.start;
 479                                 new->end = alloc.end;
 480                                 return 0;
 481                         }
 482                 }
 483
 484 next:           if (!this || this->end == root->end)
 485                         break;
 486
 487                 if (this != old)
 488                         tmp.start = this->end + 1;
 489                 this = this->sibling;
 490         }
 491         return -EBUSY;
 492 }
 493
 494 /*
 495  * Find empty slot in the resource tree given range and alignment.
 496  */
 497 static int find_resource(struct resource *root, struct resource *new,
 498                         resource_size_t size,
 499                         struct resource_constraint  *constraint)
 500 {
 501         return  __find_resource(root, NULL, new, size, constraint);
 502 }
 503
 504 /**
 505  * reallocate_resource - allocate a slot in the resource tree given range & alignment.
 506  *      The resource will be relocated if the new size cannot be reallocated in the
 507  *      current location.
 508  *
 509  * @root: root resource descriptor
 510  * @old:  resource descriptor desired by caller
 511  * @newsize: new size of the resource descriptor
 512  * @constraint: the size and alignment constraints to be met.
 513  */
 514 static int reallocate_resource(struct resource *root, struct resource *old,
 515                         resource_size_t newsize,
 516                         struct resource_constraint  *constraint)
 517 {
 518         int err=0;
 519         struct resource new = *old;
 520         struct resource *conflict;
 521
 522         write_lock(&resource_lock);
 523
 524         if ((err = __find_resource(root, old, &new, newsize, constraint)))
 525                 goto out;
 526
 527         if (resource_contains(&new, old)) {
 528                 old->start = new.start;
 529                 old->end = new.end;
 530                 goto out;
 531         }
 532
 533         if (old->child) {
 534                 err = -EBUSY;
 535                 goto out;
 536         }
 537
 538         if (resource_contains(old, &new)) {
 539                 old->start = new.start;
 540                 old->end = new.end;
 541         } else {
 542                 __release_resource(old);
 543                 *old = new;
 544                 conflict = __request_resource(root, old);
 545                 BUG_ON(conflict);
 546         }
 547 out:
 548         write_unlock(&resource_lock);
 549         return err;
 550 }
 551
 552
 553 /**
 554  * allocate_resource - allocate empty slot in the resource tree given range & alignment.
 555  *      The resource will be reallocated with a new size if it was already allocated
 556  * @root: root resource descriptor
 557  * @new: resource descriptor desired by caller
 558  * @size: requested resource region size
 559  * @min: minimum boundary to allocate
 560  * @max: maximum boundary to allocate
 561  * @align: alignment requested, in bytes
 562  * @alignf: alignment function, optional, called if not NULL
 563  * @alignf_data: arbitrary data to pass to the @alignf function
 564  */
 565 int allocate_resource(struct resource *root, struct resource *new,
 566                       resource_size_t size, resource_size_t min,
 567                       resource_size_t max, resource_size_t align,
 568                       resource_size_t (*alignf)(void *,
 569                                                 const struct resource *,
 570                                                 resource_size_t,
 571                                                 resource_size_t),
 572                       void *alignf_data)
 573 {
 574         int err;
 575         struct resource_constraint constraint;
 576
 577         if (!alignf)
 578                 alignf = simple_align_resource;
 579
 580         constraint.min = min;
 581         constraint.max = max;
 582         constraint.align = align;
 583         constraint.alignf = alignf;
 584         constraint.alignf_data = alignf_data;
 585
 586         if ( new->parent ) {
 587                 /* resource is already allocated, try reallocating with
 588                    the new constraints */
 589                 return reallocate_resource(root, new, size, &constraint);
 590         }
 591
 592         write_lock(&resource_lock);
 593         err = find_resource(root, new, size, &constraint);
 594         if (err >= 0 && __request_resource(root, new))
 595                 err = -EBUSY;
 596         write_unlock(&resource_lock);
 597         return err;
 598 }
 599
 600 EXPORT_SYMBOL(allocate_resource);
 601
 602 /**
 603  * lookup_resource - find an existing resource by a resource start address
 604  * @root: root resource descriptor
 605  * @start: resource start address
 606  *
 607  * Returns a pointer to the resource if found, NULL otherwise
 608  */
 609 struct resource *lookup_resource(struct resource *root, resource_size_t start)
 610 {
 611         struct resource *res;
 612
 613         read_lock(&resource_lock);
 614         for (res = root->child; res; res = res->sibling) {
 615                 if (res->start == start)
 616                         break;
 617         }
 618         read_unlock(&resource_lock);
 619
 620         return res;
 621 }
 622
 623 /*
 624  * Insert a resource into the resource tree. If successful, return NULL,
 625  * otherwise return the conflicting resource (compare to __request_resource())
 626  */
 627 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 628 {
 629         struct resource *first, *next;
 630
 631         for (;; parent = first) {
 632                 first = __request_resource(parent, new);
 633                 if (!first)
 634                         return first;
 635
 636                 if (first == parent)
 637                         return first;
 638                 if (WARN_ON(first == new))      /* duplicated insertion */
 639                         return first;
 640
 641                 if ((first->start > new->start) || (first->end < new->end))
 642                         break;
 643                 if ((first->start == new->start) && (first->end == new->end))
 644                         break;
 645         }
 646
 647         for (next = first; ; next = next->sibling) {
 648                 /* Partial overlap? Bad, and unfixable */
 649                 if (next->start < new->start || next->end > new->end)
 650                         return next;
 651                 if (!next->sibling)
 652                         break;
 653                 if (next->sibling->start > new->end)
 654                         break;
 655         }
 656
 657         new->parent = parent;
 658         new->sibling = next->sibling;
 659         new->child = first;
 660
 661         next->sibling = NULL;
 662         for (next = first; next; next = next->sibling)
 663                 next->parent = new;
 664
 665         if (parent->child == first) {
 666                 parent->child = new;
 667         } else {
 668                 next = parent->child;
 669                 while (next->sibling != first)
 670                         next = next->sibling;
 671                 next->sibling = new;
 672         }
 673         return NULL;
 674 }
 675
 676 /**
 677  * insert_resource_conflict - Inserts resource in the resource tree
 678  * @parent: parent of the new resource
 679  * @new: new resource to insert
 680  *
 681  * Returns 0 on success, conflict resource if the resource can't be inserted.
 682  *
 683  * This function is equivalent to request_resource_conflict when no conflict
 684  * happens. If a conflict happens, and the conflicting resources
 685  * entirely fit within the range of the new resource, then the new
 686  * resource is inserted and the conflicting resources become children of
 687  * the new resource.
 688  */
 689 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 690 {
 691         struct resource *conflict;
 692
 693         write_lock(&resource_lock);
 694         conflict = __insert_resource(parent, new);
 695         write_unlock(&resource_lock);
 696         return conflict;
 697 }
 698
 699 /**
 700  * insert_resource - Inserts a resource in the resource tree
 701  * @parent: parent of the new resource
 702  * @new: new resource to insert
 703  *
 704  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 705  */
 706 int insert_resource(struct resource *parent, struct resource *new)
 707 {
 708         struct resource *conflict;
 709
 710         conflict = insert_resource_conflict(parent, new);
 711         return conflict ? -EBUSY : 0;
 712 }
 713
 714 /**
 715  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 716  * @root: root resource descriptor
 717  * @new: new resource to insert
 718  *
 719  * Insert a resource into the resource tree, possibly expanding it in order
 720  * to make it encompass any conflicting resources.
 721  */
 722 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 723 {
 724         if (new->parent)
 725                 return;
 726
 727         write_lock(&resource_lock);
 728         for (;;) {
 729                 struct resource *conflict;
 730
 731                 conflict = __insert_resource(root, new);
 732                 if (!conflict)
 733                         break;
 734                 if (conflict == root)
 735                         break;
 736
 737                 /* Ok, expand resource to cover the conflict, then try again .. */
 738                 if (conflict->start < new->start)
 739                         new->start = conflict->start;
 740                 if (conflict->end > new->end)
 741                         new->end = conflict->end;
 742
 743                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 744         }
 745         write_unlock(&resource_lock);
 746 }
 747
 748 static int __adjust_resource(struct resource *res, resource_size_t start,
 749                                 resource_size_t size)
 750 {
 751         struct resource *tmp, *parent = res->parent;
 752         resource_size_t end = start + size - 1;
 753         int result = -EBUSY;
 754
 755         if (!parent)
 756                 goto skip;
 757
 758         if ((start < parent->start) || (end > parent->end))
 759                 goto out;
 760
 761         if (res->sibling && (res->sibling->start <= end))
 762                 goto out;
 763
 764         tmp = parent->child;
 765         if (tmp != res) {
 766                 while (tmp->sibling != res)
 767                         tmp = tmp->sibling;
 768                 if (start <= tmp->end)
 769                         goto out;
 770         }
 771
 772 skip:
 773         for (tmp = res->child; tmp; tmp = tmp->sibling)
 774                 if ((tmp->start < start) || (tmp->end > end))
 775                         goto out;
 776
 777         res->start = start;
 778         res->end = end;
 779         result = 0;
 780
 781  out:
 782         return result;
 783 }
 784
 785 /**
 786  * adjust_resource - modify a resource's start and size
 787  * @res: resource to modify
 788  * @start: new start value
 789  * @size: new size
 790  *
 791  * Given an existing resource, change its start and size to match the
 792  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 793  * Existing children of the resource are assumed to be immutable.
 794  */
 795 int adjust_resource(struct resource *res, resource_size_t start,
 796                         resource_size_t size)
 797 {
 798         int result;
 799
 800         write_lock(&resource_lock);
 801         result = __adjust_resource(res, start, size);
 802         write_unlock(&resource_lock);
 803         return result;
 804 }
 805 EXPORT_SYMBOL(adjust_resource);
 806
 807 static void __init __reserve_region_with_split(struct resource *root,
 808                 resource_size_t start, resource_size_t end,
 809                 const char *name)
 810 {
 811         struct resource *parent = root;
 812         struct resource *conflict;
 813         struct resource *res = alloc_resource(GFP_ATOMIC);
 814         struct resource *next_res = NULL;
 815
 816         if (!res)
 817                 return;
 818
 819         res->name = name;
 820         res->start = start;
 821         res->end = end;
 822         res->flags = IORESOURCE_BUSY;
 823
 824         while (1) {
 825
 826                 conflict = __request_resource(parent, res);
 827                 if (!conflict) {
 828                         if (!next_res)
 829                                 break;
 830                         res = next_res;
 831                         next_res = NULL;
 832                         continue;
 833                 }
 834
 835                 /* conflict covered whole area */
 836                 if (conflict->start <= res->start &&
 837                                 conflict->end >= res->end) {
 838                         free_resource(res);
 839                         WARN_ON(next_res);
 840                         break;
 841                 }
 842
 843                 /* failed, split and try again */
 844                 if (conflict->start > res->start) {
 845                         end = res->end;
 846                         res->end = conflict->start - 1;
 847                         if (conflict->end < end) {
 848                                 next_res = alloc_resource(GFP_ATOMIC);
 849                                 if (!next_res) {
 850                                         free_resource(res);
 851                                         break;
 852                                 }
 853                                 next_res->name = name;
 854                                 next_res->start = conflict->end + 1;
 855                                 next_res->end = end;
 856                                 next_res->flags = IORESOURCE_BUSY;
 857                         }
 858                 } else {
 859                         res->start = conflict->end + 1;
 860                 }
 861         }
 862
 863 }
 864
 865 void __init reserve_region_with_split(struct resource *root,
 866                 resource_size_t start, resource_size_t end,
 867                 const char *name)
 868 {
 869         int abort = 0;
 870
 871         write_lock(&resource_lock);
 872         if (root->start > start || root->end < end) {
 873                 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
 874                        (unsigned long long)start, (unsigned long long)end,
 875                        root);
 876                 if (start > root->end || end < root->start)
 877                         abort = 1;
 878                 else {
 879                         if (end > root->end)
 880                                 end = root->end;
 881                         if (start < root->start)
 882                                 start = root->start;
 883                         pr_err("fixing request to [0x%llx-0x%llx]\n",
 884                                (unsigned long long)start,
 885                                (unsigned long long)end);
 886                 }
 887                 dump_stack();
 888         }
 889         if (!abort)
 890                 __reserve_region_with_split(root, start, end, name);
 891         write_unlock(&resource_lock);
 892 }
 893
 894 /**
 895  * resource_alignment - calculate resource's alignment
 896  * @res: resource pointer
 897  *
 898  * Returns alignment on success, 0 (invalid alignment) on failure.
 899  */
 900 resource_size_t resource_alignment(struct resource *res)
 901 {
 902         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 903         case IORESOURCE_SIZEALIGN:
 904                 return resource_size(res);
 905         case IORESOURCE_STARTALIGN:
 906                 return res->start;
 907         default:
 908                 return 0;
 909         }
 910 }
 911
 912 /*
 913  * This is compatibility stuff for IO resources.
 914  *
 915  * Note how this, unlike the above, knows about
 916  * the IO flag meanings (busy etc).
 917  *
 918  * request_region creates a new busy region.
 919  *
 920  * check_region returns non-zero if the area is already busy.
 921  *
 922  * release_region releases a matching busy region.
 923  */
 924
 925 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
 926
 927 /**
 928  * __request_region - create a new busy resource region
 929  * @parent: parent resource descriptor
 930  * @start: resource start address
 931  * @n: resource region size
 932  * @name: reserving caller's ID string
 933  * @flags: IO resource flags
 934  */
 935 struct resource * __request_region(struct resource *parent,
 936                                    resource_size_t start, resource_size_t n,
 937                                    const char *name, int flags)
 938 {
 939         DECLARE_WAITQUEUE(wait, current);
 940         struct resource *res = alloc_resource(GFP_KERNEL);
 941
 942         if (!res)
 943                 return NULL;
 944
 945         res->name = name;
 946         res->start = start;
 947         res->end = start + n - 1;
 948         res->flags = resource_type(parent);
 949         res->flags |= IORESOURCE_BUSY | flags;
 950
 951         write_lock(&resource_lock);
 952
 953         for (;;) {
 954                 struct resource *conflict;
 955
 956                 conflict = __request_resource(parent, res);
 957                 if (!conflict)
 958                         break;
 959                 if (conflict != parent) {
 960                         parent = conflict;
 961                         if (!(conflict->flags & IORESOURCE_BUSY))
 962                                 continue;
 963                 }
 964                 if (conflict->flags & flags & IORESOURCE_MUXED) {
 965                         add_wait_queue(&muxed_resource_wait, &wait);
 966                         write_unlock(&resource_lock);
 967                         set_current_state(TASK_UNINTERRUPTIBLE);
 968                         schedule();
 969                         remove_wait_queue(&muxed_resource_wait, &wait);
 970                         write_lock(&resource_lock);
 971                         continue;
 972                 }
 973                 /* Uhhuh, that didn't work out.. */
 974                 free_resource(res);
 975                 res = NULL;
 976                 break;
 977         }
 978         write_unlock(&resource_lock);
 979         return res;
 980 }
 981 EXPORT_SYMBOL(__request_region);
 982
 983 /**
 984  * __check_region - check if a resource region is busy or free
 985  * @parent: parent resource descriptor
 986  * @start: resource start address
 987  * @n: resource region size
 988  *
 989  * Returns 0 if the region is free at the moment it is checked,
 990  * returns %-EBUSY if the region is busy.
 991  *
 992  * NOTE:
 993  * This function is deprecated because its use is racy.
 994  * Even if it returns 0, a subsequent call to request_region()
 995  * may fail because another driver etc. just allocated the region.
 996  * Do NOT use it.  It will be removed from the kernel.
 997  */
 998 int __check_region(struct resource *parent, resource_size_t start,
 999                         resource_size_t n)
1000 {
1001         struct resource * res;
1002
1003         res = __request_region(parent, start, n, "check-region", 0);
1004         if (!res)
1005                 return -EBUSY;
1006
1007         release_resource(res);
1008         free_resource(res);
1009         return 0;
1010 }
1011 EXPORT_SYMBOL(__check_region);
1012
1013 /**
1014  * __release_region - release a previously reserved resource region
1015  * @parent: parent resource descriptor
1016  * @start: resource start address
1017  * @n: resource region size
1018  *
1019  * The described resource region must match a currently busy region.
1020  */
1021 void __release_region(struct resource *parent, resource_size_t start,
1022                         resource_size_t n)
1023 {
1024         struct resource **p;
1025         resource_size_t end;
1026
1027         p = &parent->child;
1028         end = start + n - 1;
1029
1030         write_lock(&resource_lock);
1031
1032         for (;;) {
1033                 struct resource *res = *p;
1034
1035                 if (!res)
1036                         break;
1037                 if (res->start <= start && res->end >= end) {
1038                         if (!(res->flags & IORESOURCE_BUSY)) {
1039                                 p = &res->child;
1040                                 continue;
1041                         }
1042                         if (res->start != start || res->end != end)
1043                                 break;
1044                         *p = res->sibling;
1045                         write_unlock(&resource_lock);
1046                         if (res->flags & IORESOURCE_MUXED)
1047                                 wake_up(&muxed_resource_wait);
1048                         free_resource(res);
1049                         return;
1050                 }
1051                 p = &res->sibling;
1052         }
1053
1054         write_unlock(&resource_lock);
1055
1056         printk(KERN_WARNING "Trying to free nonexistent resource "
1057                 "<%016llx-%016llx>\n", (unsigned long long)start,
1058                 (unsigned long long)end);
1059 }
1060 EXPORT_SYMBOL(__release_region);
1061
1062 #ifdef CONFIG_MEMORY_HOTREMOVE
1063 /**
1064  * release_mem_region_adjustable - release a previously reserved memory region
1065  * @parent: parent resource descriptor
1066  * @start: resource start address
1067  * @size: resource region size
1068  *
1069  * This interface is intended for memory hot-delete.  The requested region
1070  * is released from a currently busy memory resource.  The requested region
1071  * must either match exactly or fit into a single busy resource entry.  In
1072  * the latter case, the remaining resource is adjusted accordingly.
1073  * Existing children of the busy memory resource must be immutable in the
1074  * request.
1075  *
1076  * Note:
1077  * - Additional release conditions, such as overlapping region, can be
1078  *   supported after they are confirmed as valid cases.
1079  * - When a busy memory resource gets split into two entries, the code
1080  *   assumes that all children remain in the lower address entry for
1081  *   simplicity.  Enhance this logic when necessary.
1082  */
1083 int release_mem_region_adjustable(struct resource *parent,
1084                         resource_size_t start, resource_size_t size)
1085 {
1086         struct resource **p;
1087         struct resource *res;
1088         struct resource *new_res;
1089         resource_size_t end;
1090         int ret = -EINVAL;
1091
1092         end = start + size - 1;
1093         if ((start < parent->start) || (end > parent->end))
1094                 return ret;
1095
1096         /* The alloc_resource() result gets checked later */
1097         new_res = alloc_resource(GFP_KERNEL);
1098
1099         p = &parent->child;
1100         write_lock(&resource_lock);
1101
1102         while ((res = *p)) {
1103                 if (res->start >= end)
1104                         break;
1105
1106                 /* look for the next resource if it does not fit into */
1107                 if (res->start > start || res->end < end) {
1108                         p = &res->sibling;
1109                         continue;
1110                 }
1111
1112                 if (!(res->flags & IORESOURCE_MEM))
1113                         break;
1114
1115                 if (!(res->flags & IORESOURCE_BUSY)) {
1116                         p = &res->child;
1117                         continue;
1118                 }
1119
1120                 /* found the target resource; let's adjust accordingly */
1121                 if (res->start == start && res->end == end) {
1122                         /* free the whole entry */
1123                         *p = res->sibling;
1124                         free_resource(res);
1125                         ret = 0;
1126                 } else if (res->start == start && res->end != end) {
1127                         /* adjust the start */
1128                         ret = __adjust_resource(res, end + 1,
1129                                                 res->end - end);
1130                 } else if (res->start != start && res->end == end) {
1131                         /* adjust the end */
1132                         ret = __adjust_resource(res, res->start,
1133                                                 start - res->start);
1134                 } else {
1135                         /* split into two entries */
1136                         if (!new_res) {
1137                                 ret = -ENOMEM;
1138                                 break;
1139                         }
1140                         new_res->name = res->name;
1141                         new_res->start = end + 1;
1142                         new_res->end = res->end;
1143                         new_res->flags = res->flags;
1144                         new_res->parent = res->parent;
1145                         new_res->sibling = res->sibling;
1146                         new_res->child = NULL;
1147
1148                         ret = __adjust_resource(res, res->start,
1149                                                 start - res->start);
1150                         if (ret)
1151                                 break;
1152                         res->sibling = new_res;
1153                         new_res = NULL;
1154                 }
1155
1156                 break;
1157         }
1158
1159         write_unlock(&resource_lock);
1160         free_resource(new_res);
1161         return ret;
1162 }
1163 #endif  /* CONFIG_MEMORY_HOTREMOVE */
1164
1165 /*
1166  * Managed region resource
1167  */
1168 struct region_devres {
1169         struct resource *parent;
1170         resource_size_t start;
1171         resource_size_t n;
1172 };
1173
1174 static void devm_region_release(struct device *dev, void *res)
1175 {
1176         struct region_devres *this = res;
1177
1178         __release_region(this->parent, this->start, this->n);
1179 }
1180
1181 static int devm_region_match(struct device *dev, void *res, void *match_data)
1182 {
1183         struct region_devres *this = res, *match = match_data;
1184
1185         return this->parent == match->parent &&
1186                 this->start == match->start && this->n == match->n;
1187 }
1188
1189 struct resource * __devm_request_region(struct device *dev,
1190                                 struct resource *parent, resource_size_t start,
1191                                 resource_size_t n, const char *name)
1192 {
1193         struct region_devres *dr = NULL;
1194         struct resource *res;
1195
1196         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1197                           GFP_KERNEL);
1198         if (!dr)
1199                 return NULL;
1200
1201         dr->parent = parent;
1202         dr->start = start;
1203         dr->n = n;
1204
1205         res = __request_region(parent, start, n, name, 0);
1206         if (res)
1207                 devres_add(dev, dr);
1208         else
1209                 devres_free(dr);
1210
1211         return res;
1212 }
1213 EXPORT_SYMBOL(__devm_request_region);
1214
1215 void __devm_release_region(struct device *dev, struct resource *parent,
1216                            resource_size_t start, resource_size_t n)
1217 {
1218         struct region_devres match_data = { parent, start, n };
1219
1220         __release_region(parent, start, n);
1221         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1222                                &match_data));
1223 }
1224 EXPORT_SYMBOL(__devm_release_region);
1225
1226 /*
1227  * Called from init/main.c to reserve IO ports.
1228  */
1229 #define MAXRESERVE 4
1230 static int __init reserve_setup(char *str)
1231 {
1232         static int reserved;
1233         static struct resource reserve[MAXRESERVE];
1234
1235         for (;;) {
1236                 unsigned int io_start, io_num;
1237                 int x = reserved;
1238
1239                 if (get_option (&str, &io_start) != 2)
1240                         break;
1241                 if (get_option (&str, &io_num)   == 0)
1242                         break;
1243                 if (x < MAXRESERVE) {
1244                         struct resource *res = reserve + x;
1245                         res->name = "reserved";
1246                         res->start = io_start;
1247                         res->end = io_start + io_num - 1;
1248                         res->flags = IORESOURCE_BUSY;
1249                         res->child = NULL;
1250                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1251                                 reserved = x+1;
1252                 }
1253         }
1254         return 1;
1255 }
1256
1257 __setup("reserve=", reserve_setup);
1258
1259 /*
1260  * Check if the requested addr and size spans more than any slot in the
1261  * iomem resource tree.
1262  */
1263 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1264 {
1265         struct resource *p = &iomem_resource;
1266         int err = 0;
1267         loff_t l;
1268
1269         read_lock(&resource_lock);
1270         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1271                 /*
1272                  * We can probably skip the resources without
1273                  * IORESOURCE_IO attribute?
1274                  */
1275                 if (p->start >= addr + size)
1276                         continue;
1277                 if (p->end < addr)
1278                         continue;
1279                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1280                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1281                         continue;
1282                 /*
1283                  * if a resource is "BUSY", it's not a hardware resource
1284                  * but a driver mapping of such a resource; we don't want
1285                  * to warn for those; some drivers legitimately map only
1286                  * partial hardware resources. (example: vesafb)
1287                  */
1288                 if (p->flags & IORESOURCE_BUSY)
1289                         continue;
1290
1291                 printk(KERN_WARNING "resource map sanity check conflict: "
1292                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
1293                        (unsigned long long)addr,
1294                        (unsigned long long)(addr + size - 1),
1295                        (unsigned long long)p->start,
1296                        (unsigned long long)p->end,
1297                        p->name);
1298                 err = -1;
1299                 break;
1300         }
1301         read_unlock(&resource_lock);
1302
1303         return err;
1304 }
1305
1306 #ifdef CONFIG_STRICT_DEVMEM
1307 static int strict_iomem_checks = 1;
1308 #else
1309 static int strict_iomem_checks;
1310 #endif
1311
1312 /*
1313  * check if an address is reserved in the iomem resource tree
1314  * returns 1 if reserved, 0 if not reserved.
1315  */
1316 int iomem_is_exclusive(u64 addr)
1317 {
1318         struct resource *p = &iomem_resource;
1319         int err = 0;
1320         loff_t l;
1321         int size = PAGE_SIZE;
1322
1323         if (!strict_iomem_checks)
1324                 return 0;
1325
1326         addr = addr & PAGE_MASK;
1327
1328         read_lock(&resource_lock);
1329         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1330                 /*
1331                  * We can probably skip the resources without
1332                  * IORESOURCE_IO attribute?
1333                  */
1334                 if (p->start >= addr + size)
1335                         break;
1336                 if (p->end < addr)
1337                         continue;
1338                 if (p->flags & IORESOURCE_BUSY &&
1339                      p->flags & IORESOURCE_EXCLUSIVE) {
1340                         err = 1;
1341                         break;
1342                 }
1343         }
1344         read_unlock(&resource_lock);
1345
1346         return err;
1347 }
1348
1349 static int __init strict_iomem(char *str)
1350 {
1351         if (strstr(str, "relaxed"))
1352                 strict_iomem_checks = 0;
1353         if (strstr(str, "strict"))
1354                 strict_iomem_checks = 1;
1355         return 1;
1356 }
1357
1358 __setup("iomem=", strict_iomem);