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
 413 void __weak arch_remove_reservations(struct resource *avail)
 414 {
 415 }
 416
 417 static resource_size_t simple_align_resource(void *data,
 418                                              const struct resource *avail,
 419                                              resource_size_t size,
 420                                              resource_size_t align)
 421 {
 422         return avail->start;
 423 }
 424
 425 static void resource_clip(struct resource *res, resource_size_t min,
 426                           resource_size_t max)
 427 {
 428         if (res->start < min)
 429                 res->start = min;
 430         if (res->end > max)
 431                 res->end = max;
 432 }
 433
 434 static bool resource_contains(struct resource *res1, struct resource *res2)
 435 {
 436         return res1->start <= res2->start && res1->end >= res2->end;
 437 }
 438
 439 /*
 440  * Find empty slot in the resource tree with the given range and
 441  * alignment constraints
 442  */
 443 static int __find_resource(struct resource *root, struct resource *old,
 444                          struct resource *new,
 445                          resource_size_t  size,
 446                          struct resource_constraint *constraint)
 447 {
 448         struct resource *this = root->child;
 449         struct resource tmp = *new, avail, alloc;
 450
 451         tmp.flags = new->flags;
 452         tmp.start = root->start;
 453         /*
 454          * Skip past an allocated resource that starts at 0, since the assignment
 455          * of this->start - 1 to tmp->end below would cause an underflow.
 456          */
 457         if (this && this->start == root->start) {
 458                 tmp.start = (this == old) ? old->start : this->end + 1;
 459                 this = this->sibling;
 460         }
 461         for(;;) {
 462                 if (this)
 463                         tmp.end = (this == old) ?  this->end : this->start - 1;
 464                 else
 465                         tmp.end = root->end;
 466
 467                 if (tmp.end < tmp.start)
 468                         goto next;
 469
 470                 resource_clip(&tmp, constraint->min, constraint->max);
 471                 arch_remove_reservations(&tmp);
 472
 473                 /* Check for overflow after ALIGN() */
 474                 avail = *new;
 475                 avail.start = ALIGN(tmp.start, constraint->align);
 476                 avail.end = tmp.end;
 477                 if (avail.start >= tmp.start) {
 478                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
 479                                         size, constraint->align);
 480                         alloc.end = alloc.start + size - 1;
 481                         if (resource_contains(&avail, &alloc)) {
 482                                 new->start = alloc.start;
 483                                 new->end = alloc.end;
 484                                 return 0;
 485                         }
 486                 }
 487
 488 next:           if (!this || this->end == root->end)
 489                         break;
 490
 491                 if (this != old)
 492                         tmp.start = this->end + 1;
 493                 this = this->sibling;
 494         }
 495         return -EBUSY;
 496 }
 497
 498 /*
 499  * Find empty slot in the resource tree given range and alignment.
 500  */
 501 static int find_resource(struct resource *root, struct resource *new,
 502                         resource_size_t size,
 503                         struct resource_constraint  *constraint)
 504 {
 505         return  __find_resource(root, NULL, new, size, constraint);
 506 }
 507
 508 /**
 509  * reallocate_resource - allocate a slot in the resource tree given range & alignment.
 510  *      The resource will be relocated if the new size cannot be reallocated in the
 511  *      current location.
 512  *
 513  * @root: root resource descriptor
 514  * @old:  resource descriptor desired by caller
 515  * @newsize: new size of the resource descriptor
 516  * @constraint: the size and alignment constraints to be met.
 517  */
 518 int reallocate_resource(struct resource *root, struct resource *old,
 519                         resource_size_t newsize,
 520                         struct resource_constraint  *constraint)
 521 {
 522         int err=0;
 523         struct resource new = *old;
 524         struct resource *conflict;
 525
 526         write_lock(&resource_lock);
 527
 528         if ((err = __find_resource(root, old, &new, newsize, constraint)))
 529                 goto out;
 530
 531         if (resource_contains(&new, old)) {
 532                 old->start = new.start;
 533                 old->end = new.end;
 534                 goto out;
 535         }
 536
 537         if (old->child) {
 538                 err = -EBUSY;
 539                 goto out;
 540         }
 541
 542         if (resource_contains(old, &new)) {
 543                 old->start = new.start;
 544                 old->end = new.end;
 545         } else {
 546                 __release_resource(old);
 547                 *old = new;
 548                 conflict = __request_resource(root, old);
 549                 BUG_ON(conflict);
 550         }
 551 out:
 552         write_unlock(&resource_lock);
 553         return err;
 554 }
 555
 556
 557 /**
 558  * allocate_resource - allocate empty slot in the resource tree given range & alignment.
 559  *      The resource will be reallocated with a new size if it was already allocated
 560  * @root: root resource descriptor
 561  * @new: resource descriptor desired by caller
 562  * @size: requested resource region size
 563  * @min: minimum boundary to allocate
 564  * @max: maximum boundary to allocate
 565  * @align: alignment requested, in bytes
 566  * @alignf: alignment function, optional, called if not NULL
 567  * @alignf_data: arbitrary data to pass to the @alignf function
 568  */
 569 int allocate_resource(struct resource *root, struct resource *new,
 570                       resource_size_t size, resource_size_t min,
 571                       resource_size_t max, resource_size_t align,
 572                       resource_size_t (*alignf)(void *,
 573                                                 const struct resource *,
 574                                                 resource_size_t,
 575                                                 resource_size_t),
 576                       void *alignf_data)
 577 {
 578         int err;
 579         struct resource_constraint constraint;
 580
 581         if (!alignf)
 582                 alignf = simple_align_resource;
 583
 584         constraint.min = min;
 585         constraint.max = max;
 586         constraint.align = align;
 587         constraint.alignf = alignf;
 588         constraint.alignf_data = alignf_data;
 589
 590         if ( new->parent ) {
 591                 /* resource is already allocated, try reallocating with
 592                    the new constraints */
 593                 return reallocate_resource(root, new, size, &constraint);
 594         }
 595
 596         write_lock(&resource_lock);
 597         err = find_resource(root, new, size, &constraint);
 598         if (err >= 0 && __request_resource(root, new))
 599                 err = -EBUSY;
 600         write_unlock(&resource_lock);
 601         return err;
 602 }
 603
 604 EXPORT_SYMBOL(allocate_resource);
 605
 606 /**
 607  * lookup_resource - find an existing resource by a resource start address
 608  * @root: root resource descriptor
 609  * @start: resource start address
 610  *
 611  * Returns a pointer to the resource if found, NULL otherwise
 612  */
 613 struct resource *lookup_resource(struct resource *root, resource_size_t start)
 614 {
 615         struct resource *res;
 616
 617         read_lock(&resource_lock);
 618         for (res = root->child; res; res = res->sibling) {
 619                 if (res->start == start)
 620                         break;
 621         }
 622         read_unlock(&resource_lock);
 623
 624         return res;
 625 }
 626
 627 /*
 628  * Insert a resource into the resource tree. If successful, return NULL,
 629  * otherwise return the conflicting resource (compare to __request_resource())
 630  */
 631 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 632 {
 633         struct resource *first, *next;
 634
 635         for (;; parent = first) {
 636                 first = __request_resource(parent, new);
 637                 if (!first)
 638                         return first;
 639
 640                 if (first == parent)
 641                         return first;
 642                 if (WARN_ON(first == new))      /* duplicated insertion */
 643                         return first;
 644
 645                 if ((first->start > new->start) || (first->end < new->end))
 646                         break;
 647                 if ((first->start == new->start) && (first->end == new->end))
 648                         break;
 649         }
 650
 651         for (next = first; ; next = next->sibling) {
 652                 /* Partial overlap? Bad, and unfixable */
 653                 if (next->start < new->start || next->end > new->end)
 654                         return next;
 655                 if (!next->sibling)
 656                         break;
 657                 if (next->sibling->start > new->end)
 658                         break;
 659         }
 660
 661         new->parent = parent;
 662         new->sibling = next->sibling;
 663         new->child = first;
 664
 665         next->sibling = NULL;
 666         for (next = first; next; next = next->sibling)
 667                 next->parent = new;
 668
 669         if (parent->child == first) {
 670                 parent->child = new;
 671         } else {
 672                 next = parent->child;
 673                 while (next->sibling != first)
 674                         next = next->sibling;
 675                 next->sibling = new;
 676         }
 677         return NULL;
 678 }
 679
 680 /**
 681  * insert_resource_conflict - Inserts resource in the resource tree
 682  * @parent: parent of the new resource
 683  * @new: new resource to insert
 684  *
 685  * Returns 0 on success, conflict resource if the resource can't be inserted.
 686  *
 687  * This function is equivalent to request_resource_conflict when no conflict
 688  * happens. If a conflict happens, and the conflicting resources
 689  * entirely fit within the range of the new resource, then the new
 690  * resource is inserted and the conflicting resources become children of
 691  * the new resource.
 692  */
 693 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 694 {
 695         struct resource *conflict;
 696
 697         write_lock(&resource_lock);
 698         conflict = __insert_resource(parent, new);
 699         write_unlock(&resource_lock);
 700         return conflict;
 701 }
 702
 703 /**
 704  * insert_resource - Inserts a resource in the resource tree
 705  * @parent: parent of the new resource
 706  * @new: new resource to insert
 707  *
 708  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 709  */
 710 int insert_resource(struct resource *parent, struct resource *new)
 711 {
 712         struct resource *conflict;
 713
 714         conflict = insert_resource_conflict(parent, new);
 715         return conflict ? -EBUSY : 0;
 716 }
 717
 718 /**
 719  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 720  * @root: root resource descriptor
 721  * @new: new resource to insert
 722  *
 723  * Insert a resource into the resource tree, possibly expanding it in order
 724  * to make it encompass any conflicting resources.
 725  */
 726 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 727 {
 728         if (new->parent)
 729                 return;
 730
 731         write_lock(&resource_lock);
 732         for (;;) {
 733                 struct resource *conflict;
 734
 735                 conflict = __insert_resource(root, new);
 736                 if (!conflict)
 737                         break;
 738                 if (conflict == root)
 739                         break;
 740
 741                 /* Ok, expand resource to cover the conflict, then try again .. */
 742                 if (conflict->start < new->start)
 743                         new->start = conflict->start;
 744                 if (conflict->end > new->end)
 745                         new->end = conflict->end;
 746
 747                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 748         }
 749         write_unlock(&resource_lock);
 750 }
 751
 752 static int __adjust_resource(struct resource *res, resource_size_t start,
 753                                 resource_size_t size)
 754 {
 755         struct resource *tmp, *parent = res->parent;
 756         resource_size_t end = start + size - 1;
 757         int result = -EBUSY;
 758
 759         if (!parent)
 760                 goto skip;
 761
 762         if ((start < parent->start) || (end > parent->end))
 763                 goto out;
 764
 765         if (res->sibling && (res->sibling->start <= end))
 766                 goto out;
 767
 768         tmp = parent->child;
 769         if (tmp != res) {
 770                 while (tmp->sibling != res)
 771                         tmp = tmp->sibling;
 772                 if (start <= tmp->end)
 773                         goto out;
 774         }
 775
 776 skip:
 777         for (tmp = res->child; tmp; tmp = tmp->sibling)
 778                 if ((tmp->start < start) || (tmp->end > end))
 779                         goto out;
 780
 781         res->start = start;
 782         res->end = end;
 783         result = 0;
 784
 785  out:
 786         return result;
 787 }
 788
 789 /**
 790  * adjust_resource - modify a resource's start and size
 791  * @res: resource to modify
 792  * @start: new start value
 793  * @size: new size
 794  *
 795  * Given an existing resource, change its start and size to match the
 796  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 797  * Existing children of the resource are assumed to be immutable.
 798  */
 799 int adjust_resource(struct resource *res, resource_size_t start,
 800                         resource_size_t size)
 801 {
 802         int result;
 803
 804         write_lock(&resource_lock);
 805         result = __adjust_resource(res, start, size);
 806         write_unlock(&resource_lock);
 807         return result;
 808 }
 809 EXPORT_SYMBOL(adjust_resource);
 810
 811 static void __init __reserve_region_with_split(struct resource *root,
 812                 resource_size_t start, resource_size_t end,
 813                 const char *name)
 814 {
 815         struct resource *parent = root;
 816         struct resource *conflict;
 817         struct resource *res = alloc_resource(GFP_ATOMIC);
 818         struct resource *next_res = NULL;
 819
 820         if (!res)
 821                 return;
 822
 823         res->name = name;
 824         res->start = start;
 825         res->end = end;
 826         res->flags = IORESOURCE_BUSY;
 827
 828         while (1) {
 829
 830                 conflict = __request_resource(parent, res);
 831                 if (!conflict) {
 832                         if (!next_res)
 833                                 break;
 834                         res = next_res;
 835                         next_res = NULL;
 836                         continue;
 837                 }
 838
 839                 /* conflict covered whole area */
 840                 if (conflict->start <= res->start &&
 841                                 conflict->end >= res->end) {
 842                         free_resource(res);
 843                         WARN_ON(next_res);
 844                         break;
 845                 }
 846
 847                 /* failed, split and try again */
 848                 if (conflict->start > res->start) {
 849                         end = res->end;
 850                         res->end = conflict->start - 1;
 851                         if (conflict->end < end) {
 852                                 next_res = alloc_resource(GFP_ATOMIC);
 853                                 if (!next_res) {
 854                                         free_resource(res);
 855                                         break;
 856                                 }
 857                                 next_res->name = name;
 858                                 next_res->start = conflict->end + 1;
 859                                 next_res->end = end;
 860                                 next_res->flags = IORESOURCE_BUSY;
 861                         }
 862                 } else {
 863                         res->start = conflict->end + 1;
 864                 }
 865         }
 866
 867 }
 868
 869 void __init reserve_region_with_split(struct resource *root,
 870                 resource_size_t start, resource_size_t end,
 871                 const char *name)
 872 {
 873         int abort = 0;
 874
 875         write_lock(&resource_lock);
 876         if (root->start > start || root->end < end) {
 877                 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
 878                        (unsigned long long)start, (unsigned long long)end,
 879                        root);
 880                 if (start > root->end || end < root->start)
 881                         abort = 1;
 882                 else {
 883                         if (end > root->end)
 884                                 end = root->end;
 885                         if (start < root->start)
 886                                 start = root->start;
 887                         pr_err("fixing request to [0x%llx-0x%llx]\n",
 888                                (unsigned long long)start,
 889                                (unsigned long long)end);
 890                 }
 891                 dump_stack();
 892         }
 893         if (!abort)
 894                 __reserve_region_with_split(root, start, end, name);
 895         write_unlock(&resource_lock);
 896 }
 897
 898 /**
 899  * resource_alignment - calculate resource's alignment
 900  * @res: resource pointer
 901  *
 902  * Returns alignment on success, 0 (invalid alignment) on failure.
 903  */
 904 resource_size_t resource_alignment(struct resource *res)
 905 {
 906         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 907         case IORESOURCE_SIZEALIGN:
 908                 return resource_size(res);
 909         case IORESOURCE_STARTALIGN:
 910                 return res->start;
 911         default:
 912                 return 0;
 913         }
 914 }
 915
 916 /*
 917  * This is compatibility stuff for IO resources.
 918  *
 919  * Note how this, unlike the above, knows about
 920  * the IO flag meanings (busy etc).
 921  *
 922  * request_region creates a new busy region.
 923  *
 924  * check_region returns non-zero if the area is already busy.
 925  *
 926  * release_region releases a matching busy region.
 927  */
 928
 929 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
 930
 931 /**
 932  * __request_region - create a new busy resource region
 933  * @parent: parent resource descriptor
 934  * @start: resource start address
 935  * @n: resource region size
 936  * @name: reserving caller's ID string
 937  * @flags: IO resource flags
 938  */
 939 struct resource * __request_region(struct resource *parent,
 940                                    resource_size_t start, resource_size_t n,
 941                                    const char *name, int flags)
 942 {
 943         DECLARE_WAITQUEUE(wait, current);
 944         struct resource *res = alloc_resource(GFP_KERNEL);
 945
 946         if (!res)
 947                 return NULL;
 948
 949         res->name = name;
 950         res->start = start;
 951         res->end = start + n - 1;
 952         res->flags = IORESOURCE_BUSY;
 953         res->flags |= flags;
 954
 955         write_lock(&resource_lock);
 956
 957         for (;;) {
 958                 struct resource *conflict;
 959
 960                 conflict = __request_resource(parent, res);
 961                 if (!conflict)
 962                         break;
 963                 if (conflict != parent) {
 964                         parent = conflict;
 965                         if (!(conflict->flags & IORESOURCE_BUSY))
 966                                 continue;
 967                 }
 968                 if (conflict->flags & flags & IORESOURCE_MUXED) {
 969                         add_wait_queue(&muxed_resource_wait, &wait);
 970                         write_unlock(&resource_lock);
 971                         set_current_state(TASK_UNINTERRUPTIBLE);
 972                         schedule();
 973                         remove_wait_queue(&muxed_resource_wait, &wait);
 974                         write_lock(&resource_lock);
 975                         continue;
 976                 }
 977                 /* Uhhuh, that didn't work out.. */
 978                 free_resource(res);
 979                 res = NULL;
 980                 break;
 981         }
 982         write_unlock(&resource_lock);
 983         return res;
 984 }
 985 EXPORT_SYMBOL(__request_region);
 986
 987 /**
 988  * __check_region - check if a resource region is busy or free
 989  * @parent: parent resource descriptor
 990  * @start: resource start address
 991  * @n: resource region size
 992  *
 993  * Returns 0 if the region is free at the moment it is checked,
 994  * returns %-EBUSY if the region is busy.
 995  *
 996  * NOTE:
 997  * This function is deprecated because its use is racy.
 998  * Even if it returns 0, a subsequent call to request_region()
 999  * may fail because another driver etc. just allocated the region.
1000  * Do NOT use it.  It will be removed from the kernel.
1001  */
1002 int __check_region(struct resource *parent, resource_size_t start,
1003                         resource_size_t n)
1004 {
1005         struct resource * res;
1006
1007         res = __request_region(parent, start, n, "check-region", 0);
1008         if (!res)
1009                 return -EBUSY;
1010
1011         release_resource(res);
1012         free_resource(res);
1013         return 0;
1014 }
1015 EXPORT_SYMBOL(__check_region);
1016
1017 /**
1018  * __release_region - release a previously reserved resource region
1019  * @parent: parent resource descriptor
1020  * @start: resource start address
1021  * @n: resource region size
1022  *
1023  * The described resource region must match a currently busy region.
1024  */
1025 void __release_region(struct resource *parent, resource_size_t start,
1026                         resource_size_t n)
1027 {
1028         struct resource **p;
1029         resource_size_t end;
1030
1031         p = &parent->child;
1032         end = start + n - 1;
1033
1034         write_lock(&resource_lock);
1035
1036         for (;;) {
1037                 struct resource *res = *p;
1038
1039                 if (!res)
1040                         break;
1041                 if (res->start <= start && res->end >= end) {
1042                         if (!(res->flags & IORESOURCE_BUSY)) {
1043                                 p = &res->child;
1044                                 continue;
1045                         }
1046                         if (res->start != start || res->end != end)
1047                                 break;
1048                         *p = res->sibling;
1049                         write_unlock(&resource_lock);
1050                         if (res->flags & IORESOURCE_MUXED)
1051                                 wake_up(&muxed_resource_wait);
1052                         free_resource(res);
1053                         return;
1054                 }
1055                 p = &res->sibling;
1056         }
1057
1058         write_unlock(&resource_lock);
1059
1060         printk(KERN_WARNING "Trying to free nonexistent resource "
1061                 "<%016llx-%016llx>\n", (unsigned long long)start,
1062                 (unsigned long long)end);
1063 }
1064 EXPORT_SYMBOL(__release_region);
1065
1066 #ifdef CONFIG_MEMORY_HOTREMOVE
1067 /**
1068  * release_mem_region_adjustable - release a previously reserved memory region
1069  * @parent: parent resource descriptor
1070  * @start: resource start address
1071  * @size: resource region size
1072  *
1073  * This interface is intended for memory hot-delete.  The requested region
1074  * is released from a currently busy memory resource.  The requested region
1075  * must either match exactly or fit into a single busy resource entry.  In
1076  * the latter case, the remaining resource is adjusted accordingly.
1077  * Existing children of the busy memory resource must be immutable in the
1078  * request.
1079  *
1080  * Note:
1081  * - Additional release conditions, such as overlapping region, can be
1082  *   supported after they are confirmed as valid cases.
1083  * - When a busy memory resource gets split into two entries, the code
1084  *   assumes that all children remain in the lower address entry for
1085  *   simplicity.  Enhance this logic when necessary.
1086  */
1087 int release_mem_region_adjustable(struct resource *parent,
1088                         resource_size_t start, resource_size_t size)
1089 {
1090         struct resource **p;
1091         struct resource *res;
1092         struct resource *new_res;
1093         resource_size_t end;
1094         int ret = -EINVAL;
1095
1096         end = start + size - 1;
1097         if ((start < parent->start) || (end > parent->end))
1098                 return ret;
1099
1100         /* The alloc_resource() result gets checked later */
1101         new_res = alloc_resource(GFP_KERNEL);
1102
1103         p = &parent->child;
1104         write_lock(&resource_lock);
1105
1106         while ((res = *p)) {
1107                 if (res->start >= end)
1108                         break;
1109
1110                 /* look for the next resource if it does not fit into */
1111                 if (res->start > start || res->end < end) {
1112                         p = &res->sibling;
1113                         continue;
1114                 }
1115
1116                 if (!(res->flags & IORESOURCE_MEM))
1117                         break;
1118
1119                 if (!(res->flags & IORESOURCE_BUSY)) {
1120                         p = &res->child;
1121                         continue;
1122                 }
1123
1124                 /* found the target resource; let's adjust accordingly */
1125                 if (res->start == start && res->end == end) {
1126                         /* free the whole entry */
1127                         *p = res->sibling;
1128                         free_resource(res);
1129                         ret = 0;
1130                 } else if (res->start == start && res->end != end) {
1131                         /* adjust the start */
1132                         ret = __adjust_resource(res, end + 1,
1133                                                 res->end - end);
1134                 } else if (res->start != start && res->end == end) {
1135                         /* adjust the end */
1136                         ret = __adjust_resource(res, res->start,
1137                                                 start - res->start);
1138                 } else {
1139                         /* split into two entries */
1140                         if (!new_res) {
1141                                 ret = -ENOMEM;
1142                                 break;
1143                         }
1144                         new_res->name = res->name;
1145                         new_res->start = end + 1;
1146                         new_res->end = res->end;
1147                         new_res->flags = res->flags;
1148                         new_res->parent = res->parent;
1149                         new_res->sibling = res->sibling;
1150                         new_res->child = NULL;
1151
1152                         ret = __adjust_resource(res, res->start,
1153                                                 start - res->start);
1154                         if (ret)
1155                                 break;
1156                         res->sibling = new_res;
1157                         new_res = NULL;
1158                 }
1159
1160                 break;
1161         }
1162
1163         write_unlock(&resource_lock);
1164         free_resource(new_res);
1165         return ret;
1166 }
1167 #endif  /* CONFIG_MEMORY_HOTREMOVE */
1168
1169 /*
1170  * Managed region resource
1171  */
1172 struct region_devres {
1173         struct resource *parent;
1174         resource_size_t start;
1175         resource_size_t n;
1176 };
1177
1178 static void devm_region_release(struct device *dev, void *res)
1179 {
1180         struct region_devres *this = res;
1181
1182         __release_region(this->parent, this->start, this->n);
1183 }
1184
1185 static int devm_region_match(struct device *dev, void *res, void *match_data)
1186 {
1187         struct region_devres *this = res, *match = match_data;
1188
1189         return this->parent == match->parent &&
1190                 this->start == match->start && this->n == match->n;
1191 }
1192
1193 struct resource * __devm_request_region(struct device *dev,
1194                                 struct resource *parent, resource_size_t start,
1195                                 resource_size_t n, const char *name)
1196 {
1197         struct region_devres *dr = NULL;
1198         struct resource *res;
1199
1200         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1201                           GFP_KERNEL);
1202         if (!dr)
1203                 return NULL;
1204
1205         dr->parent = parent;
1206         dr->start = start;
1207         dr->n = n;
1208
1209         res = __request_region(parent, start, n, name, 0);
1210         if (res)
1211                 devres_add(dev, dr);
1212         else
1213                 devres_free(dr);
1214
1215         return res;
1216 }
1217 EXPORT_SYMBOL(__devm_request_region);
1218
1219 void __devm_release_region(struct device *dev, struct resource *parent,
1220                            resource_size_t start, resource_size_t n)
1221 {
1222         struct region_devres match_data = { parent, start, n };
1223
1224         __release_region(parent, start, n);
1225         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1226                                &match_data));
1227 }
1228 EXPORT_SYMBOL(__devm_release_region);
1229
1230 /*
1231  * Called from init/main.c to reserve IO ports.
1232  */
1233 #define MAXRESERVE 4
1234 static int __init reserve_setup(char *str)
1235 {
1236         static int reserved;
1237         static struct resource reserve[MAXRESERVE];
1238
1239         for (;;) {
1240                 unsigned int io_start, io_num;
1241                 int x = reserved;
1242
1243                 if (get_option (&str, &io_start) != 2)
1244                         break;
1245                 if (get_option (&str, &io_num)   == 0)
1246                         break;
1247                 if (x < MAXRESERVE) {
1248                         struct resource *res = reserve + x;
1249                         res->name = "reserved";
1250                         res->start = io_start;
1251                         res->end = io_start + io_num - 1;
1252                         res->flags = IORESOURCE_BUSY;
1253                         res->child = NULL;
1254                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1255                                 reserved = x+1;
1256                 }
1257         }
1258         return 1;
1259 }
1260
1261 __setup("reserve=", reserve_setup);
1262
1263 /*
1264  * Check if the requested addr and size spans more than any slot in the
1265  * iomem resource tree.
1266  */
1267 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1268 {
1269         struct resource *p = &iomem_resource;
1270         int err = 0;
1271         loff_t l;
1272
1273         read_lock(&resource_lock);
1274         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1275                 /*
1276                  * We can probably skip the resources without
1277                  * IORESOURCE_IO attribute?
1278                  */
1279                 if (p->start >= addr + size)
1280                         continue;
1281                 if (p->end < addr)
1282                         continue;
1283                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1284                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1285                         continue;
1286                 /*
1287                  * if a resource is "BUSY", it's not a hardware resource
1288                  * but a driver mapping of such a resource; we don't want
1289                  * to warn for those; some drivers legitimately map only
1290                  * partial hardware resources. (example: vesafb)
1291                  */
1292                 if (p->flags & IORESOURCE_BUSY)
1293                         continue;
1294
1295                 printk(KERN_WARNING "resource map sanity check conflict: "
1296                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
1297                        (unsigned long long)addr,
1298                        (unsigned long long)(addr + size - 1),
1299                        (unsigned long long)p->start,
1300                        (unsigned long long)p->end,
1301                        p->name);
1302                 err = -1;
1303                 break;
1304         }
1305         read_unlock(&resource_lock);
1306
1307         return err;
1308 }
1309
1310 #ifdef CONFIG_STRICT_DEVMEM
1311 static int strict_iomem_checks = 1;
1312 #else
1313 static int strict_iomem_checks;
1314 #endif
1315
1316 /*
1317  * check if an address is reserved in the iomem resource tree
1318  * returns 1 if reserved, 0 if not reserved.
1319  */
1320 int iomem_is_exclusive(u64 addr)
1321 {
1322         struct resource *p = &iomem_resource;
1323         int err = 0;
1324         loff_t l;
1325         int size = PAGE_SIZE;
1326
1327         if (!strict_iomem_checks)
1328                 return 0;
1329
1330         addr = addr & PAGE_MASK;
1331
1332         read_lock(&resource_lock);
1333         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1334                 /*
1335                  * We can probably skip the resources without
1336                  * IORESOURCE_IO attribute?
1337                  */
1338                 if (p->start >= addr + size)
1339                         break;
1340                 if (p->end < addr)
1341                         continue;
1342                 if (p->flags & IORESOURCE_BUSY &&
1343                      p->flags & IORESOURCE_EXCLUSIVE) {
1344                         err = 1;
1345                         break;
1346                 }
1347         }
1348         read_unlock(&resource_lock);
1349
1350         return err;
1351 }
1352
1353 static int __init strict_iomem(char *str)
1354 {
1355         if (strstr(str, "relaxed"))
1356                 strict_iomem_checks = 0;
1357         if (strstr(str, "strict"))
1358                 strict_iomem_checks = 1;
1359         return 1;
1360 }
1361
1362 __setup("iomem=", strict_iomem);