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 struct resource *next_resource(struct resource *p, bool sibling_only)
  63 {
  64         /* Caller wants to traverse through siblings only */
  65         if (sibling_only)
  66                 return p->sibling;
  67
  68         if (p->child)
  69                 return p->child;
  70         while (!p->sibling && p->parent)
  71                 p = p->parent;
  72         return p->sibling;
  73 }
  74
  75 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  76 {
  77         struct resource *p = v;
  78         (*pos)++;
  79         return (void *)next_resource(p, false);
  80 }
  81
  82 #ifdef CONFIG_PROC_FS
  83
  84 enum { MAX_IORES_LEVEL = 5 };
  85
  86 static void *r_start(struct seq_file *m, loff_t *pos)
  87         __acquires(resource_lock)
  88 {
  89         struct resource *p = m->private;
  90         loff_t l = 0;
  91         read_lock(&resource_lock);
  92         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  93                 ;
  94         return p;
  95 }
  96
  97 static void r_stop(struct seq_file *m, void *v)
  98         __releases(resource_lock)
  99 {
 100         read_unlock(&resource_lock);
 101 }
 102
 103 static int r_show(struct seq_file *m, void *v)
 104 {
 105         struct resource *root = m->private;
 106         struct resource *r = v, *p;
 107         int width = root->end < 0x10000 ? 4 : 8;
 108         int depth;
 109
 110         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
 111                 if (p->parent == root)
 112                         break;
 113         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
 114                         depth * 2, "",
 115                         width, (unsigned long long) r->start,
 116                         width, (unsigned long long) r->end,
 117                         r->name ? r->name : "<BAD>");
 118         return 0;
 119 }
 120
 121 static const struct seq_operations resource_op = {
 122         .start  = r_start,
 123         .next   = r_next,
 124         .stop   = r_stop,
 125         .show   = r_show,
 126 };
 127
 128 static int ioports_open(struct inode *inode, struct file *file)
 129 {
 130         int res = seq_open(file, &resource_op);
 131         if (!res) {
 132                 struct seq_file *m = file->private_data;
 133                 m->private = &ioport_resource;
 134         }
 135         return res;
 136 }
 137
 138 static int iomem_open(struct inode *inode, struct file *file)
 139 {
 140         int res = seq_open(file, &resource_op);
 141         if (!res) {
 142                 struct seq_file *m = file->private_data;
 143                 m->private = &iomem_resource;
 144         }
 145         return res;
 146 }
 147
 148 static const struct file_operations proc_ioports_operations = {
 149         .open           = ioports_open,
 150         .read           = seq_read,
 151         .llseek         = seq_lseek,
 152         .release        = seq_release,
 153 };
 154
 155 static const struct file_operations proc_iomem_operations = {
 156         .open           = iomem_open,
 157         .read           = seq_read,
 158         .llseek         = seq_lseek,
 159         .release        = seq_release,
 160 };
 161
 162 static int __init ioresources_init(void)
 163 {
 164         proc_create("ioports", 0, NULL, &proc_ioports_operations);
 165         proc_create("iomem", 0, NULL, &proc_iomem_operations);
 166         return 0;
 167 }
 168 __initcall(ioresources_init);
 169
 170 #endif /* CONFIG_PROC_FS */
 171
 172 static void free_resource(struct resource *res)
 173 {
 174         if (!res)
 175                 return;
 176
 177         if (!PageSlab(virt_to_head_page(res))) {
 178                 spin_lock(&bootmem_resource_lock);
 179                 res->sibling = bootmem_resource_free;
 180                 bootmem_resource_free = res;
 181                 spin_unlock(&bootmem_resource_lock);
 182         } else {
 183                 kfree(res);
 184         }
 185 }
 186
 187 static struct resource *alloc_resource(gfp_t flags)
 188 {
 189         struct resource *res = NULL;
 190
 191         spin_lock(&bootmem_resource_lock);
 192         if (bootmem_resource_free) {
 193                 res = bootmem_resource_free;
 194                 bootmem_resource_free = res->sibling;
 195         }
 196         spin_unlock(&bootmem_resource_lock);
 197
 198         if (res)
 199                 memset(res, 0, sizeof(struct resource));
 200         else
 201                 res = kzalloc(sizeof(struct resource), flags);
 202
 203         return res;
 204 }
 205
 206 /* Return the conflict entry if you can't request it */
 207 static struct resource * __request_resource(struct resource *root, struct resource *new)
 208 {
 209         resource_size_t start = new->start;
 210         resource_size_t end = new->end;
 211         struct resource *tmp, **p;
 212
 213         if (end < start)
 214                 return root;
 215         if (start < root->start)
 216                 return root;
 217         if (end > root->end)
 218                 return root;
 219         p = &root->child;
 220         for (;;) {
 221                 tmp = *p;
 222                 if (!tmp || tmp->start > end) {
 223                         new->sibling = tmp;
 224                         *p = new;
 225                         new->parent = root;
 226                         return NULL;
 227                 }
 228                 p = &tmp->sibling;
 229                 if (tmp->end < start)
 230                         continue;
 231                 return tmp;
 232         }
 233 }
 234
 235 static int __release_resource(struct resource *old)
 236 {
 237         struct resource *tmp, **p;
 238
 239         p = &old->parent->child;
 240         for (;;) {
 241                 tmp = *p;
 242                 if (!tmp)
 243                         break;
 244                 if (tmp == old) {
 245                         *p = tmp->sibling;
 246                         old->parent = NULL;
 247                         return 0;
 248                 }
 249                 p = &tmp->sibling;
 250         }
 251         return -EINVAL;
 252 }
 253
 254 static void __release_child_resources(struct resource *r)
 255 {
 256         struct resource *tmp, *p;
 257         resource_size_t size;
 258
 259         p = r->child;
 260         r->child = NULL;
 261         while (p) {
 262                 tmp = p;
 263                 p = p->sibling;
 264
 265                 tmp->parent = NULL;
 266                 tmp->sibling = NULL;
 267                 __release_child_resources(tmp);
 268
 269                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
 270                 /* need to restore size, and keep flags */
 271                 size = resource_size(tmp);
 272                 tmp->start = 0;
 273                 tmp->end = size - 1;
 274         }
 275 }
 276
 277 void release_child_resources(struct resource *r)
 278 {
 279         write_lock(&resource_lock);
 280         __release_child_resources(r);
 281         write_unlock(&resource_lock);
 282 }
 283
 284 /**
 285  * request_resource_conflict - request and reserve an I/O or memory resource
 286  * @root: root resource descriptor
 287  * @new: resource descriptor desired by caller
 288  *
 289  * Returns 0 for success, conflict resource on error.
 290  */
 291 struct resource *request_resource_conflict(struct resource *root, struct resource *new)
 292 {
 293         struct resource *conflict;
 294
 295         write_lock(&resource_lock);
 296         conflict = __request_resource(root, new);
 297         write_unlock(&resource_lock);
 298         return conflict;
 299 }
 300
 301 /**
 302  * request_resource - request and reserve an I/O or memory resource
 303  * @root: root resource descriptor
 304  * @new: resource descriptor desired by caller
 305  *
 306  * Returns 0 for success, negative error code on error.
 307  */
 308 int request_resource(struct resource *root, struct resource *new)
 309 {
 310         struct resource *conflict;
 311
 312         conflict = request_resource_conflict(root, new);
 313         return conflict ? -EBUSY : 0;
 314 }
 315
 316 EXPORT_SYMBOL(request_resource);
 317
 318 /**
 319  * release_resource - release a previously reserved resource
 320  * @old: resource pointer
 321  */
 322 int release_resource(struct resource *old)
 323 {
 324         int retval;
 325
 326         write_lock(&resource_lock);
 327         retval = __release_resource(old);
 328         write_unlock(&resource_lock);
 329         return retval;
 330 }
 331
 332 EXPORT_SYMBOL(release_resource);
 333
 334 /*
 335  * Finds the lowest iomem reosurce exists with-in [res->start.res->end)
 336  * the caller must specify res->start, res->end, res->flags and "name".
 337  * If found, returns 0, res is overwritten, if not found, returns -1.
 338  * This walks through whole tree and not just first level children
 339  * until and unless first_level_children_only is true.
 340  */
 341 static int find_next_iomem_res(struct resource *res, char *name,
 342                                bool first_level_children_only)
 343 {
 344         resource_size_t start, end;
 345         struct resource *p;
 346         bool sibling_only = false;
 347
 348         BUG_ON(!res);
 349
 350         start = res->start;
 351         end = res->end;
 352         BUG_ON(start >= end);
 353
 354         if (first_level_children_only)
 355                 sibling_only = true;
 356
 357         read_lock(&resource_lock);
 358
 359         for (p = iomem_resource.child; p; p = next_resource(p, sibling_only)) {
 360                 if (p->flags != res->flags)
 361                         continue;
 362                 if (name && strcmp(p->name, name))
 363                         continue;
 364                 if (p->start > end) {
 365                         p = NULL;
 366                         break;
 367                 }
 368                 if ((p->end >= start) && (p->start < end))
 369                         break;
 370         }
 371
 372         read_unlock(&resource_lock);
 373         if (!p)
 374                 return -1;
 375         /* copy data */
 376         if (res->start < p->start)
 377                 res->start = p->start;
 378         if (res->end > p->end)
 379                 res->end = p->end;
 380         return 0;
 381 }
 382
 383 /*
 384  * Walks through iomem resources and calls func() with matching resource
 385  * ranges. This walks through whole tree and not just first level children.
 386  * All the memory ranges which overlap start,end and also match flags and
 387  * name are valid candidates.
 388  *
 389  * @name: name of resource
 390  * @flags: resource flags
 391  * @start: start addr
 392  * @end: end addr
 393  */
 394 int walk_iomem_res(char *name, unsigned long flags, u64 start, u64 end,
 395                 void *arg, int (*func)(u64, u64, void *))
 396 {
 397         struct resource res;
 398         u64 orig_end;
 399         int ret = -1;
 400
 401         res.start = start;
 402         res.end = end;
 403         res.flags = flags;
 404         orig_end = res.end;
 405         while ((res.start < res.end) &&
 406                 (!find_next_iomem_res(&res, name, false))) {
 407                 ret = (*func)(res.start, res.end, arg);
 408                 if (ret)
 409                         break;
 410                 res.start = res.end + 1;
 411                 res.end = orig_end;
 412         }
 413         return ret;
 414 }
 415
 416 /*
 417  * This function calls callback against all memory range of "System RAM"
 418  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 419  * Now, this function is only for "System RAM". This function deals with
 420  * full ranges and not pfn. If resources are not pfn aligned, dealing
 421  * with pfn can truncate ranges.
 422  */
 423 int walk_system_ram_res(u64 start, u64 end, void *arg,
 424                                 int (*func)(u64, u64, void *))
 425 {
 426         struct resource res;
 427         u64 orig_end;
 428         int ret = -1;
 429
 430         res.start = start;
 431         res.end = end;
 432         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 433         orig_end = res.end;
 434         while ((res.start < res.end) &&
 435                 (!find_next_iomem_res(&res, "System RAM", true))) {
 436                 ret = (*func)(res.start, res.end, arg);
 437                 if (ret)
 438                         break;
 439                 res.start = res.end + 1;
 440                 res.end = orig_end;
 441         }
 442         return ret;
 443 }
 444
 445 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 446
 447 /*
 448  * This function calls callback against all memory range of "System RAM"
 449  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 450  * Now, this function is only for "System RAM".
 451  */
 452 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 453                 void *arg, int (*func)(unsigned long, unsigned long, void *))
 454 {
 455         struct resource res;
 456         unsigned long pfn, end_pfn;
 457         u64 orig_end;
 458         int ret = -1;
 459
 460         res.start = (u64) start_pfn << PAGE_SHIFT;
 461         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 462         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 463         orig_end = res.end;
 464         while ((res.start < res.end) &&
 465                 (find_next_iomem_res(&res, "System RAM", true) >= 0)) {
 466                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 467                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
 468                 if (end_pfn > pfn)
 469                         ret = (*func)(pfn, end_pfn - pfn, arg);
 470                 if (ret)
 471                         break;
 472                 res.start = res.end + 1;
 473                 res.end = orig_end;
 474         }
 475         return ret;
 476 }
 477
 478 #endif
 479
 480 static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
 481 {
 482         return 1;
 483 }
 484 /*
 485  * This generic page_is_ram() returns true if specified address is
 486  * registered as "System RAM" in iomem_resource list.
 487  */
 488 int __weak page_is_ram(unsigned long pfn)
 489 {
 490         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 491 }
 492 EXPORT_SYMBOL_GPL(page_is_ram);
 493
 494 /*
 495  * Search for a resouce entry that fully contains the specified region.
 496  * If found, return 1 if it is RAM, 0 if not.
 497  * If not found, or region is not fully contained, return -1
 498  *
 499  * Used by the ioremap functions to ensure the user is not remapping RAM and is
 500  * a vast speed up over walking through the resource table page by page.
 501  */
 502 int region_is_ram(resource_size_t start, unsigned long size)
 503 {
 504         struct resource *p;
 505         resource_size_t end = start + size - 1;
 506         int flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 507         const char *name = "System RAM";
 508         int ret = -1;
 509
 510         read_lock(&resource_lock);
 511         for (p = iomem_resource.child; p ; p = p->sibling) {
 512                 if (end < p->start)
 513                         continue;
 514
 515                 if (p->start <= start && end <= p->end) {
 516                         /* resource fully contains region */
 517                         if ((p->flags != flags) || strcmp(p->name, name))
 518                                 ret = 0;
 519                         else
 520                                 ret = 1;
 521                         break;
 522                 }
 523                 if (p->end < start)
 524                         break;  /* not found */
 525         }
 526         read_unlock(&resource_lock);
 527         return ret;
 528 }
 529
 530 void __weak arch_remove_reservations(struct resource *avail)
 531 {
 532 }
 533
 534 static resource_size_t simple_align_resource(void *data,
 535                                              const struct resource *avail,
 536                                              resource_size_t size,
 537                                              resource_size_t align)
 538 {
 539         return avail->start;
 540 }
 541
 542 static void resource_clip(struct resource *res, resource_size_t min,
 543                           resource_size_t max)
 544 {
 545         if (res->start < min)
 546                 res->start = min;
 547         if (res->end > max)
 548                 res->end = max;
 549 }
 550
 551 /*
 552  * Find empty slot in the resource tree with the given range and
 553  * alignment constraints
 554  */
 555 static int __find_resource(struct resource *root, struct resource *old,
 556                          struct resource *new,
 557                          resource_size_t  size,
 558                          struct resource_constraint *constraint)
 559 {
 560         struct resource *this = root->child;
 561         struct resource tmp = *new, avail, alloc;
 562
 563         tmp.start = root->start;
 564         /*
 565          * Skip past an allocated resource that starts at 0, since the assignment
 566          * of this->start - 1 to tmp->end below would cause an underflow.
 567          */
 568         if (this && this->start == root->start) {
 569                 tmp.start = (this == old) ? old->start : this->end + 1;
 570                 this = this->sibling;
 571         }
 572         for(;;) {
 573                 if (this)
 574                         tmp.end = (this == old) ?  this->end : this->start - 1;
 575                 else
 576                         tmp.end = root->end;
 577
 578                 if (tmp.end < tmp.start)
 579                         goto next;
 580
 581                 resource_clip(&tmp, constraint->min, constraint->max);
 582                 arch_remove_reservations(&tmp);
 583
 584                 /* Check for overflow after ALIGN() */
 585                 avail.start = ALIGN(tmp.start, constraint->align);
 586                 avail.end = tmp.end;
 587                 avail.flags = new->flags & ~IORESOURCE_UNSET;
 588                 if (avail.start >= tmp.start) {
 589                         alloc.flags = avail.flags;
 590                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
 591                                         size, constraint->align);
 592                         alloc.end = alloc.start + size - 1;
 593                         if (resource_contains(&avail, &alloc)) {
 594                                 new->start = alloc.start;
 595                                 new->end = alloc.end;
 596                                 return 0;
 597                         }
 598                 }
 599
 600 next:           if (!this || this->end == root->end)
 601                         break;
 602
 603                 if (this != old)
 604                         tmp.start = this->end + 1;
 605                 this = this->sibling;
 606         }
 607         return -EBUSY;
 608 }
 609
 610 /*
 611  * Find empty slot in the resource tree given range and alignment.
 612  */
 613 static int find_resource(struct resource *root, struct resource *new,
 614                         resource_size_t size,
 615                         struct resource_constraint  *constraint)
 616 {
 617         return  __find_resource(root, NULL, new, size, constraint);
 618 }
 619
 620 /**
 621  * reallocate_resource - allocate a slot in the resource tree given range & alignment.
 622  *      The resource will be relocated if the new size cannot be reallocated in the
 623  *      current location.
 624  *
 625  * @root: root resource descriptor
 626  * @old:  resource descriptor desired by caller
 627  * @newsize: new size of the resource descriptor
 628  * @constraint: the size and alignment constraints to be met.
 629  */
 630 static int reallocate_resource(struct resource *root, struct resource *old,
 631                         resource_size_t newsize,
 632                         struct resource_constraint  *constraint)
 633 {
 634         int err=0;
 635         struct resource new = *old;
 636         struct resource *conflict;
 637
 638         write_lock(&resource_lock);
 639
 640         if ((err = __find_resource(root, old, &new, newsize, constraint)))
 641                 goto out;
 642
 643         if (resource_contains(&new, old)) {
 644                 old->start = new.start;
 645                 old->end = new.end;
 646                 goto out;
 647         }
 648
 649         if (old->child) {
 650                 err = -EBUSY;
 651                 goto out;
 652         }
 653
 654         if (resource_contains(old, &new)) {
 655                 old->start = new.start;
 656                 old->end = new.end;
 657         } else {
 658                 __release_resource(old);
 659                 *old = new;
 660                 conflict = __request_resource(root, old);
 661                 BUG_ON(conflict);
 662         }
 663 out:
 664         write_unlock(&resource_lock);
 665         return err;
 666 }
 667
 668
 669 /**
 670  * allocate_resource - allocate empty slot in the resource tree given range & alignment.
 671  *      The resource will be reallocated with a new size if it was already allocated
 672  * @root: root resource descriptor
 673  * @new: resource descriptor desired by caller
 674  * @size: requested resource region size
 675  * @min: minimum boundary to allocate
 676  * @max: maximum boundary to allocate
 677  * @align: alignment requested, in bytes
 678  * @alignf: alignment function, optional, called if not NULL
 679  * @alignf_data: arbitrary data to pass to the @alignf function
 680  */
 681 int allocate_resource(struct resource *root, struct resource *new,
 682                       resource_size_t size, resource_size_t min,
 683                       resource_size_t max, resource_size_t align,
 684                       resource_size_t (*alignf)(void *,
 685                                                 const struct resource *,
 686                                                 resource_size_t,
 687                                                 resource_size_t),
 688                       void *alignf_data)
 689 {
 690         int err;
 691         struct resource_constraint constraint;
 692
 693         if (!alignf)
 694                 alignf = simple_align_resource;
 695
 696         constraint.min = min;
 697         constraint.max = max;
 698         constraint.align = align;
 699         constraint.alignf = alignf;
 700         constraint.alignf_data = alignf_data;
 701
 702         if ( new->parent ) {
 703                 /* resource is already allocated, try reallocating with
 704                    the new constraints */
 705                 return reallocate_resource(root, new, size, &constraint);
 706         }
 707
 708         write_lock(&resource_lock);
 709         err = find_resource(root, new, size, &constraint);
 710         if (err >= 0 && __request_resource(root, new))
 711                 err = -EBUSY;
 712         write_unlock(&resource_lock);
 713         return err;
 714 }
 715
 716 EXPORT_SYMBOL(allocate_resource);
 717
 718 /**
 719  * lookup_resource - find an existing resource by a resource start address
 720  * @root: root resource descriptor
 721  * @start: resource start address
 722  *
 723  * Returns a pointer to the resource if found, NULL otherwise
 724  */
 725 struct resource *lookup_resource(struct resource *root, resource_size_t start)
 726 {
 727         struct resource *res;
 728
 729         read_lock(&resource_lock);
 730         for (res = root->child; res; res = res->sibling) {
 731                 if (res->start == start)
 732                         break;
 733         }
 734         read_unlock(&resource_lock);
 735
 736         return res;
 737 }
 738
 739 /*
 740  * Insert a resource into the resource tree. If successful, return NULL,
 741  * otherwise return the conflicting resource (compare to __request_resource())
 742  */
 743 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 744 {
 745         struct resource *first, *next;
 746
 747         for (;; parent = first) {
 748                 first = __request_resource(parent, new);
 749                 if (!first)
 750                         return first;
 751
 752                 if (first == parent)
 753                         return first;
 754                 if (WARN_ON(first == new))      /* duplicated insertion */
 755                         return first;
 756
 757                 if ((first->start > new->start) || (first->end < new->end))
 758                         break;
 759                 if ((first->start == new->start) && (first->end == new->end))
 760                         break;
 761         }
 762
 763         for (next = first; ; next = next->sibling) {
 764                 /* Partial overlap? Bad, and unfixable */
 765                 if (next->start < new->start || next->end > new->end)
 766                         return next;
 767                 if (!next->sibling)
 768                         break;
 769                 if (next->sibling->start > new->end)
 770                         break;
 771         }
 772
 773         new->parent = parent;
 774         new->sibling = next->sibling;
 775         new->child = first;
 776
 777         next->sibling = NULL;
 778         for (next = first; next; next = next->sibling)
 779                 next->parent = new;
 780
 781         if (parent->child == first) {
 782                 parent->child = new;
 783         } else {
 784                 next = parent->child;
 785                 while (next->sibling != first)
 786                         next = next->sibling;
 787                 next->sibling = new;
 788         }
 789         return NULL;
 790 }
 791
 792 /**
 793  * insert_resource_conflict - Inserts resource in the resource tree
 794  * @parent: parent of the new resource
 795  * @new: new resource to insert
 796  *
 797  * Returns 0 on success, conflict resource if the resource can't be inserted.
 798  *
 799  * This function is equivalent to request_resource_conflict when no conflict
 800  * happens. If a conflict happens, and the conflicting resources
 801  * entirely fit within the range of the new resource, then the new
 802  * resource is inserted and the conflicting resources become children of
 803  * the new resource.
 804  */
 805 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 806 {
 807         struct resource *conflict;
 808
 809         write_lock(&resource_lock);
 810         conflict = __insert_resource(parent, new);
 811         write_unlock(&resource_lock);
 812         return conflict;
 813 }
 814
 815 /**
 816  * insert_resource - Inserts a resource in the resource tree
 817  * @parent: parent of the new resource
 818  * @new: new resource to insert
 819  *
 820  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 821  */
 822 int insert_resource(struct resource *parent, struct resource *new)
 823 {
 824         struct resource *conflict;
 825
 826         conflict = insert_resource_conflict(parent, new);
 827         return conflict ? -EBUSY : 0;
 828 }
 829
 830 /**
 831  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 832  * @root: root resource descriptor
 833  * @new: new resource to insert
 834  *
 835  * Insert a resource into the resource tree, possibly expanding it in order
 836  * to make it encompass any conflicting resources.
 837  */
 838 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 839 {
 840         if (new->parent)
 841                 return;
 842
 843         write_lock(&resource_lock);
 844         for (;;) {
 845                 struct resource *conflict;
 846
 847                 conflict = __insert_resource(root, new);
 848                 if (!conflict)
 849                         break;
 850                 if (conflict == root)
 851                         break;
 852
 853                 /* Ok, expand resource to cover the conflict, then try again .. */
 854                 if (conflict->start < new->start)
 855                         new->start = conflict->start;
 856                 if (conflict->end > new->end)
 857                         new->end = conflict->end;
 858
 859                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 860         }
 861         write_unlock(&resource_lock);
 862 }
 863
 864 static int __adjust_resource(struct resource *res, resource_size_t start,
 865                                 resource_size_t size)
 866 {
 867         struct resource *tmp, *parent = res->parent;
 868         resource_size_t end = start + size - 1;
 869         int result = -EBUSY;
 870
 871         if (!parent)
 872                 goto skip;
 873
 874         if ((start < parent->start) || (end > parent->end))
 875                 goto out;
 876
 877         if (res->sibling && (res->sibling->start <= end))
 878                 goto out;
 879
 880         tmp = parent->child;
 881         if (tmp != res) {
 882                 while (tmp->sibling != res)
 883                         tmp = tmp->sibling;
 884                 if (start <= tmp->end)
 885                         goto out;
 886         }
 887
 888 skip:
 889         for (tmp = res->child; tmp; tmp = tmp->sibling)
 890                 if ((tmp->start < start) || (tmp->end > end))
 891                         goto out;
 892
 893         res->start = start;
 894         res->end = end;
 895         result = 0;
 896
 897  out:
 898         return result;
 899 }
 900
 901 /**
 902  * adjust_resource - modify a resource's start and size
 903  * @res: resource to modify
 904  * @start: new start value
 905  * @size: new size
 906  *
 907  * Given an existing resource, change its start and size to match the
 908  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 909  * Existing children of the resource are assumed to be immutable.
 910  */
 911 int adjust_resource(struct resource *res, resource_size_t start,
 912                         resource_size_t size)
 913 {
 914         int result;
 915
 916         write_lock(&resource_lock);
 917         result = __adjust_resource(res, start, size);
 918         write_unlock(&resource_lock);
 919         return result;
 920 }
 921 EXPORT_SYMBOL(adjust_resource);
 922
 923 static void __init __reserve_region_with_split(struct resource *root,
 924                 resource_size_t start, resource_size_t end,
 925                 const char *name)
 926 {
 927         struct resource *parent = root;
 928         struct resource *conflict;
 929         struct resource *res = alloc_resource(GFP_ATOMIC);
 930         struct resource *next_res = NULL;
 931
 932         if (!res)
 933                 return;
 934
 935         res->name = name;
 936         res->start = start;
 937         res->end = end;
 938         res->flags = IORESOURCE_BUSY;
 939
 940         while (1) {
 941
 942                 conflict = __request_resource(parent, res);
 943                 if (!conflict) {
 944                         if (!next_res)
 945                                 break;
 946                         res = next_res;
 947                         next_res = NULL;
 948                         continue;
 949                 }
 950
 951                 /* conflict covered whole area */
 952                 if (conflict->start <= res->start &&
 953                                 conflict->end >= res->end) {
 954                         free_resource(res);
 955                         WARN_ON(next_res);
 956                         break;
 957                 }
 958
 959                 /* failed, split and try again */
 960                 if (conflict->start > res->start) {
 961                         end = res->end;
 962                         res->end = conflict->start - 1;
 963                         if (conflict->end < end) {
 964                                 next_res = alloc_resource(GFP_ATOMIC);
 965                                 if (!next_res) {
 966                                         free_resource(res);
 967                                         break;
 968                                 }
 969                                 next_res->name = name;
 970                                 next_res->start = conflict->end + 1;
 971                                 next_res->end = end;
 972                                 next_res->flags = IORESOURCE_BUSY;
 973                         }
 974                 } else {
 975                         res->start = conflict->end + 1;
 976                 }
 977         }
 978
 979 }
 980
 981 void __init reserve_region_with_split(struct resource *root,
 982                 resource_size_t start, resource_size_t end,
 983                 const char *name)
 984 {
 985         int abort = 0;
 986
 987         write_lock(&resource_lock);
 988         if (root->start > start || root->end < end) {
 989                 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
 990                        (unsigned long long)start, (unsigned long long)end,
 991                        root);
 992                 if (start > root->end || end < root->start)
 993                         abort = 1;
 994                 else {
 995                         if (end > root->end)
 996                                 end = root->end;
 997                         if (start < root->start)
 998                                 start = root->start;
 999                         pr_err("fixing request to [0x%llx-0x%llx]\n",
1000                                (unsigned long long)start,
1001                                (unsigned long long)end);
1002                 }
1003                 dump_stack();
1004         }
1005         if (!abort)
1006                 __reserve_region_with_split(root, start, end, name);
1007         write_unlock(&resource_lock);
1008 }
1009
1010 /**
1011  * resource_alignment - calculate resource's alignment
1012  * @res: resource pointer
1013  *
1014  * Returns alignment on success, 0 (invalid alignment) on failure.
1015  */
1016 resource_size_t resource_alignment(struct resource *res)
1017 {
1018         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
1019         case IORESOURCE_SIZEALIGN:
1020                 return resource_size(res);
1021         case IORESOURCE_STARTALIGN:
1022                 return res->start;
1023         default:
1024                 return 0;
1025         }
1026 }
1027
1028 /*
1029  * This is compatibility stuff for IO resources.
1030  *
1031  * Note how this, unlike the above, knows about
1032  * the IO flag meanings (busy etc).
1033  *
1034  * request_region creates a new busy region.
1035  *
1036  * check_region returns non-zero if the area is already busy.
1037  *
1038  * release_region releases a matching busy region.
1039  */
1040
1041 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
1042
1043 /**
1044  * __request_region - create a new busy resource region
1045  * @parent: parent resource descriptor
1046  * @start: resource start address
1047  * @n: resource region size
1048  * @name: reserving caller's ID string
1049  * @flags: IO resource flags
1050  */
1051 struct resource * __request_region(struct resource *parent,
1052                                    resource_size_t start, resource_size_t n,
1053                                    const char *name, int flags)
1054 {
1055         DECLARE_WAITQUEUE(wait, current);
1056         struct resource *res = alloc_resource(GFP_KERNEL);
1057
1058         if (!res)
1059                 return NULL;
1060
1061         res->name = name;
1062         res->start = start;
1063         res->end = start + n - 1;
1064         res->flags = resource_type(parent);
1065         res->flags |= IORESOURCE_BUSY | flags;
1066
1067         write_lock(&resource_lock);
1068
1069         for (;;) {
1070                 struct resource *conflict;
1071
1072                 conflict = __request_resource(parent, res);
1073                 if (!conflict)
1074                         break;
1075                 if (conflict != parent) {
1076                         parent = conflict;
1077                         if (!(conflict->flags & IORESOURCE_BUSY))
1078                                 continue;
1079                 }
1080                 if (conflict->flags & flags & IORESOURCE_MUXED) {
1081                         add_wait_queue(&muxed_resource_wait, &wait);
1082                         write_unlock(&resource_lock);
1083                         set_current_state(TASK_UNINTERRUPTIBLE);
1084                         schedule();
1085                         remove_wait_queue(&muxed_resource_wait, &wait);
1086                         write_lock(&resource_lock);
1087                         continue;
1088                 }
1089                 /* Uhhuh, that didn't work out.. */
1090                 free_resource(res);
1091                 res = NULL;
1092                 break;
1093         }
1094         write_unlock(&resource_lock);
1095         return res;
1096 }
1097 EXPORT_SYMBOL(__request_region);
1098
1099 /**
1100  * __check_region - check if a resource region is busy or free
1101  * @parent: parent resource descriptor
1102  * @start: resource start address
1103  * @n: resource region size
1104  *
1105  * Returns 0 if the region is free at the moment it is checked,
1106  * returns %-EBUSY if the region is busy.
1107  *
1108  * NOTE:
1109  * This function is deprecated because its use is racy.
1110  * Even if it returns 0, a subsequent call to request_region()
1111  * may fail because another driver etc. just allocated the region.
1112  * Do NOT use it.  It will be removed from the kernel.
1113  */
1114 int __check_region(struct resource *parent, resource_size_t start,
1115                         resource_size_t n)
1116 {
1117         struct resource * res;
1118
1119         res = __request_region(parent, start, n, "check-region", 0);
1120         if (!res)
1121                 return -EBUSY;
1122
1123         release_resource(res);
1124         free_resource(res);
1125         return 0;
1126 }
1127 EXPORT_SYMBOL(__check_region);
1128
1129 /**
1130  * __release_region - release a previously reserved resource region
1131  * @parent: parent resource descriptor
1132  * @start: resource start address
1133  * @n: resource region size
1134  *
1135  * The described resource region must match a currently busy region.
1136  */
1137 void __release_region(struct resource *parent, resource_size_t start,
1138                         resource_size_t n)
1139 {
1140         struct resource **p;
1141         resource_size_t end;
1142
1143         p = &parent->child;
1144         end = start + n - 1;
1145
1146         write_lock(&resource_lock);
1147
1148         for (;;) {
1149                 struct resource *res = *p;
1150
1151                 if (!res)
1152                         break;
1153                 if (res->start <= start && res->end >= end) {
1154                         if (!(res->flags & IORESOURCE_BUSY)) {
1155                                 p = &res->child;
1156                                 continue;
1157                         }
1158                         if (res->start != start || res->end != end)
1159                                 break;
1160                         *p = res->sibling;
1161                         write_unlock(&resource_lock);
1162                         if (res->flags & IORESOURCE_MUXED)
1163                                 wake_up(&muxed_resource_wait);
1164                         free_resource(res);
1165                         return;
1166                 }
1167                 p = &res->sibling;
1168         }
1169
1170         write_unlock(&resource_lock);
1171
1172         printk(KERN_WARNING "Trying to free nonexistent resource "
1173                 "<%016llx-%016llx>\n", (unsigned long long)start,
1174                 (unsigned long long)end);
1175 }
1176 EXPORT_SYMBOL(__release_region);
1177
1178 #ifdef CONFIG_MEMORY_HOTREMOVE
1179 /**
1180  * release_mem_region_adjustable - release a previously reserved memory region
1181  * @parent: parent resource descriptor
1182  * @start: resource start address
1183  * @size: resource region size
1184  *
1185  * This interface is intended for memory hot-delete.  The requested region
1186  * is released from a currently busy memory resource.  The requested region
1187  * must either match exactly or fit into a single busy resource entry.  In
1188  * the latter case, the remaining resource is adjusted accordingly.
1189  * Existing children of the busy memory resource must be immutable in the
1190  * request.
1191  *
1192  * Note:
1193  * - Additional release conditions, such as overlapping region, can be
1194  *   supported after they are confirmed as valid cases.
1195  * - When a busy memory resource gets split into two entries, the code
1196  *   assumes that all children remain in the lower address entry for
1197  *   simplicity.  Enhance this logic when necessary.
1198  */
1199 int release_mem_region_adjustable(struct resource *parent,
1200                         resource_size_t start, resource_size_t size)
1201 {
1202         struct resource **p;
1203         struct resource *res;
1204         struct resource *new_res;
1205         resource_size_t end;
1206         int ret = -EINVAL;
1207
1208         end = start + size - 1;
1209         if ((start < parent->start) || (end > parent->end))
1210                 return ret;
1211
1212         /* The alloc_resource() result gets checked later */
1213         new_res = alloc_resource(GFP_KERNEL);
1214
1215         p = &parent->child;
1216         write_lock(&resource_lock);
1217
1218         while ((res = *p)) {
1219                 if (res->start >= end)
1220                         break;
1221
1222                 /* look for the next resource if it does not fit into */
1223                 if (res->start > start || res->end < end) {
1224                         p = &res->sibling;
1225                         continue;
1226                 }
1227
1228                 if (!(res->flags & IORESOURCE_MEM))
1229                         break;
1230
1231                 if (!(res->flags & IORESOURCE_BUSY)) {
1232                         p = &res->child;
1233                         continue;
1234                 }
1235
1236                 /* found the target resource; let's adjust accordingly */
1237                 if (res->start == start && res->end == end) {
1238                         /* free the whole entry */
1239                         *p = res->sibling;
1240                         free_resource(res);
1241                         ret = 0;
1242                 } else if (res->start == start && res->end != end) {
1243                         /* adjust the start */
1244                         ret = __adjust_resource(res, end + 1,
1245                                                 res->end - end);
1246                 } else if (res->start != start && res->end == end) {
1247                         /* adjust the end */
1248                         ret = __adjust_resource(res, res->start,
1249                                                 start - res->start);
1250                 } else {
1251                         /* split into two entries */
1252                         if (!new_res) {
1253                                 ret = -ENOMEM;
1254                                 break;
1255                         }
1256                         new_res->name = res->name;
1257                         new_res->start = end + 1;
1258                         new_res->end = res->end;
1259                         new_res->flags = res->flags;
1260                         new_res->parent = res->parent;
1261                         new_res->sibling = res->sibling;
1262                         new_res->child = NULL;
1263
1264                         ret = __adjust_resource(res, res->start,
1265                                                 start - res->start);
1266                         if (ret)
1267                                 break;
1268                         res->sibling = new_res;
1269                         new_res = NULL;
1270                 }
1271
1272                 break;
1273         }
1274
1275         write_unlock(&resource_lock);
1276         free_resource(new_res);
1277         return ret;
1278 }
1279 #endif  /* CONFIG_MEMORY_HOTREMOVE */
1280
1281 /*
1282  * Managed region resource
1283  */
1284 static void devm_resource_release(struct device *dev, void *ptr)
1285 {
1286         struct resource **r = ptr;
1287
1288         release_resource(*r);
1289 }
1290
1291 /**
1292  * devm_request_resource() - request and reserve an I/O or memory resource
1293  * @dev: device for which to request the resource
1294  * @root: root of the resource tree from which to request the resource
1295  * @new: descriptor of the resource to request
1296  *
1297  * This is a device-managed version of request_resource(). There is usually
1298  * no need to release resources requested by this function explicitly since
1299  * that will be taken care of when the device is unbound from its driver.
1300  * If for some reason the resource needs to be released explicitly, because
1301  * of ordering issues for example, drivers must call devm_release_resource()
1302  * rather than the regular release_resource().
1303  *
1304  * When a conflict is detected between any existing resources and the newly
1305  * requested resource, an error message will be printed.
1306  *
1307  * Returns 0 on success or a negative error code on failure.
1308  */
1309 int devm_request_resource(struct device *dev, struct resource *root,
1310                           struct resource *new)
1311 {
1312         struct resource *conflict, **ptr;
1313
1314         ptr = devres_alloc(devm_resource_release, sizeof(*ptr), GFP_KERNEL);
1315         if (!ptr)
1316                 return -ENOMEM;
1317
1318         *ptr = new;
1319
1320         conflict = request_resource_conflict(root, new);
1321         if (conflict) {
1322                 dev_err(dev, "resource collision: %pR conflicts with %s %pR\n",
1323                         new, conflict->name, conflict);
1324                 devres_free(ptr);
1325                 return -EBUSY;
1326         }
1327
1328         devres_add(dev, ptr);
1329         return 0;
1330 }
1331 EXPORT_SYMBOL(devm_request_resource);
1332
1333 static int devm_resource_match(struct device *dev, void *res, void *data)
1334 {
1335         struct resource **ptr = res;
1336
1337         return *ptr == data;
1338 }
1339
1340 /**
1341  * devm_release_resource() - release a previously requested resource
1342  * @dev: device for which to release the resource
1343  * @new: descriptor of the resource to release
1344  *
1345  * Releases a resource previously requested using devm_request_resource().
1346  */
1347 void devm_release_resource(struct device *dev, struct resource *new)
1348 {
1349         WARN_ON(devres_release(dev, devm_resource_release, devm_resource_match,
1350                                new));
1351 }
1352 EXPORT_SYMBOL(devm_release_resource);
1353
1354 struct region_devres {
1355         struct resource *parent;
1356         resource_size_t start;
1357         resource_size_t n;
1358 };
1359
1360 static void devm_region_release(struct device *dev, void *res)
1361 {
1362         struct region_devres *this = res;
1363
1364         __release_region(this->parent, this->start, this->n);
1365 }
1366
1367 static int devm_region_match(struct device *dev, void *res, void *match_data)
1368 {
1369         struct region_devres *this = res, *match = match_data;
1370
1371         return this->parent == match->parent &&
1372                 this->start == match->start && this->n == match->n;
1373 }
1374
1375 struct resource * __devm_request_region(struct device *dev,
1376                                 struct resource *parent, resource_size_t start,
1377                                 resource_size_t n, const char *name)
1378 {
1379         struct region_devres *dr = NULL;
1380         struct resource *res;
1381
1382         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1383                           GFP_KERNEL);
1384         if (!dr)
1385                 return NULL;
1386
1387         dr->parent = parent;
1388         dr->start = start;
1389         dr->n = n;
1390
1391         res = __request_region(parent, start, n, name, 0);
1392         if (res)
1393                 devres_add(dev, dr);
1394         else
1395                 devres_free(dr);
1396
1397         return res;
1398 }
1399 EXPORT_SYMBOL(__devm_request_region);
1400
1401 void __devm_release_region(struct device *dev, struct resource *parent,
1402                            resource_size_t start, resource_size_t n)
1403 {
1404         struct region_devres match_data = { parent, start, n };
1405
1406         __release_region(parent, start, n);
1407         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1408                                &match_data));
1409 }
1410 EXPORT_SYMBOL(__devm_release_region);
1411
1412 /*
1413  * Called from init/main.c to reserve IO ports.
1414  */
1415 #define MAXRESERVE 4
1416 static int __init reserve_setup(char *str)
1417 {
1418         static int reserved;
1419         static struct resource reserve[MAXRESERVE];
1420
1421         for (;;) {
1422                 unsigned int io_start, io_num;
1423                 int x = reserved;
1424
1425                 if (get_option (&str, &io_start) != 2)
1426                         break;
1427                 if (get_option (&str, &io_num)   == 0)
1428                         break;
1429                 if (x < MAXRESERVE) {
1430                         struct resource *res = reserve + x;
1431                         res->name = "reserved";
1432                         res->start = io_start;
1433                         res->end = io_start + io_num - 1;
1434                         res->flags = IORESOURCE_BUSY;
1435                         res->child = NULL;
1436                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1437                                 reserved = x+1;
1438                 }
1439         }
1440         return 1;
1441 }
1442
1443 __setup("reserve=", reserve_setup);
1444
1445 /*
1446  * Check if the requested addr and size spans more than any slot in the
1447  * iomem resource tree.
1448  */
1449 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1450 {
1451         struct resource *p = &iomem_resource;
1452         int err = 0;
1453         loff_t l;
1454
1455         read_lock(&resource_lock);
1456         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1457                 /*
1458                  * We can probably skip the resources without
1459                  * IORESOURCE_IO attribute?
1460                  */
1461                 if (p->start >= addr + size)
1462                         continue;
1463                 if (p->end < addr)
1464                         continue;
1465                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1466                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1467                         continue;
1468                 /*
1469                  * if a resource is "BUSY", it's not a hardware resource
1470                  * but a driver mapping of such a resource; we don't want
1471                  * to warn for those; some drivers legitimately map only
1472                  * partial hardware resources. (example: vesafb)
1473                  */
1474                 if (p->flags & IORESOURCE_BUSY)
1475                         continue;
1476
1477                 printk(KERN_WARNING "resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
1478                        (unsigned long long)addr,
1479                        (unsigned long long)(addr + size - 1),
1480                        p->name, p);
1481                 err = -1;
1482                 break;
1483         }
1484         read_unlock(&resource_lock);
1485
1486         return err;
1487 }
1488
1489 #ifdef CONFIG_STRICT_DEVMEM
1490 static int strict_iomem_checks = 1;
1491 #else
1492 static int strict_iomem_checks;
1493 #endif
1494
1495 /*
1496  * check if an address is reserved in the iomem resource tree
1497  * returns 1 if reserved, 0 if not reserved.
1498  */
1499 int iomem_is_exclusive(u64 addr)
1500 {
1501         struct resource *p = &iomem_resource;
1502         int err = 0;
1503         loff_t l;
1504         int size = PAGE_SIZE;
1505
1506         if (!strict_iomem_checks)
1507                 return 0;
1508
1509         addr = addr & PAGE_MASK;
1510
1511         read_lock(&resource_lock);
1512         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1513                 /*
1514                  * We can probably skip the resources without
1515                  * IORESOURCE_IO attribute?
1516                  */
1517                 if (p->start >= addr + size)
1518                         break;
1519                 if (p->end < addr)
1520                         continue;
1521                 if (p->flags & IORESOURCE_BUSY &&
1522                      p->flags & IORESOURCE_EXCLUSIVE) {
1523                         err = 1;
1524                         break;
1525                 }
1526         }
1527         read_unlock(&resource_lock);
1528
1529         return err;
1530 }
1531
1532 static int __init strict_iomem(char *str)
1533 {
1534         if (strstr(str, "relaxed"))
1535                 strict_iomem_checks = 0;
1536         if (strstr(str, "strict"))
1537                 strict_iomem_checks = 1;
1538         return 1;
1539 }
1540
1541 __setup("iomem=", strict_iomem);