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         read_lock(&resource_lock);
 355
 356         if (first_level_children_only) {
 357                 p = iomem_resource.child;
 358                 sibling_only = true;
 359         } else
 360                 p = &iomem_resource;
 361
 362         while ((p = next_resource(p, sibling_only))) {
 363                 if (p->flags != res->flags)
 364                         continue;
 365                 if (name && strcmp(p->name, name))
 366                         continue;
 367                 if (p->start > end) {
 368                         p = NULL;
 369                         break;
 370                 }
 371                 if ((p->end >= start) && (p->start < end))
 372                         break;
 373         }
 374
 375         read_unlock(&resource_lock);
 376         if (!p)
 377                 return -1;
 378         /* copy data */
 379         if (res->start < p->start)
 380                 res->start = p->start;
 381         if (res->end > p->end)
 382                 res->end = p->end;
 383         return 0;
 384 }
 385
 386 /*
 387  * Walks through iomem resources and calls func() with matching resource
 388  * ranges. This walks through whole tree and not just first level children.
 389  * All the memory ranges which overlap start,end and also match flags and
 390  * name are valid candidates.
 391  *
 392  * @name: name of resource
 393  * @flags: resource flags
 394  * @start: start addr
 395  * @end: end addr
 396  */
 397 int walk_iomem_res(char *name, unsigned long flags, u64 start, u64 end,
 398                 void *arg, int (*func)(u64, u64, void *))
 399 {
 400         struct resource res;
 401         u64 orig_end;
 402         int ret = -1;
 403
 404         res.start = start;
 405         res.end = end;
 406         res.flags = flags;
 407         orig_end = res.end;
 408         while ((res.start < res.end) &&
 409                 (!find_next_iomem_res(&res, name, false))) {
 410                 ret = (*func)(res.start, res.end, arg);
 411                 if (ret)
 412                         break;
 413                 res.start = res.end + 1;
 414                 res.end = orig_end;
 415         }
 416         return ret;
 417 }
 418
 419 /*
 420  * This function calls callback against all memory range of "System RAM"
 421  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 422  * Now, this function is only for "System RAM". This function deals with
 423  * full ranges and not pfn. If resources are not pfn aligned, dealing
 424  * with pfn can truncate ranges.
 425  */
 426 int walk_system_ram_res(u64 start, u64 end, void *arg,
 427                                 int (*func)(u64, u64, void *))
 428 {
 429         struct resource res;
 430         u64 orig_end;
 431         int ret = -1;
 432
 433         res.start = start;
 434         res.end = end;
 435         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 436         orig_end = res.end;
 437         while ((res.start < res.end) &&
 438                 (!find_next_iomem_res(&res, "System RAM", true))) {
 439                 ret = (*func)(res.start, res.end, arg);
 440                 if (ret)
 441                         break;
 442                 res.start = res.end + 1;
 443                 res.end = orig_end;
 444         }
 445         return ret;
 446 }
 447
 448 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 449
 450 /*
 451  * This function calls callback against all memory range of "System RAM"
 452  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 453  * Now, this function is only for "System RAM".
 454  */
 455 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 456                 void *arg, int (*func)(unsigned long, unsigned long, void *))
 457 {
 458         struct resource res;
 459         unsigned long pfn, end_pfn;
 460         u64 orig_end;
 461         int ret = -1;
 462
 463         res.start = (u64) start_pfn << PAGE_SHIFT;
 464         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 465         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 466         orig_end = res.end;
 467         while ((res.start < res.end) &&
 468                 (find_next_iomem_res(&res, "System RAM", true) >= 0)) {
 469                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 470                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
 471                 if (end_pfn > pfn)
 472                         ret = (*func)(pfn, end_pfn - pfn, arg);
 473                 if (ret)
 474                         break;
 475                 res.start = res.end + 1;
 476                 res.end = orig_end;
 477         }
 478         return ret;
 479 }
 480
 481 #endif
 482
 483 static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
 484 {
 485         return 1;
 486 }
 487 /*
 488  * This generic page_is_ram() returns true if specified address is
 489  * registered as "System RAM" in iomem_resource list.
 490  */
 491 int __weak page_is_ram(unsigned long pfn)
 492 {
 493         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 494 }
 495 EXPORT_SYMBOL_GPL(page_is_ram);
 496
 497 void __weak arch_remove_reservations(struct resource *avail)
 498 {
 499 }
 500
 501 static resource_size_t simple_align_resource(void *data,
 502                                              const struct resource *avail,
 503                                              resource_size_t size,
 504                                              resource_size_t align)
 505 {
 506         return avail->start;
 507 }
 508
 509 static void resource_clip(struct resource *res, resource_size_t min,
 510                           resource_size_t max)
 511 {
 512         if (res->start < min)
 513                 res->start = min;
 514         if (res->end > max)
 515                 res->end = max;
 516 }
 517
 518 /*
 519  * Find empty slot in the resource tree with the given range and
 520  * alignment constraints
 521  */
 522 static int __find_resource(struct resource *root, struct resource *old,
 523                          struct resource *new,
 524                          resource_size_t  size,
 525                          struct resource_constraint *constraint)
 526 {
 527         struct resource *this = root->child;
 528         struct resource tmp = *new, avail, alloc;
 529
 530         tmp.start = root->start;
 531         /*
 532          * Skip past an allocated resource that starts at 0, since the assignment
 533          * of this->start - 1 to tmp->end below would cause an underflow.
 534          */
 535         if (this && this->start == root->start) {
 536                 tmp.start = (this == old) ? old->start : this->end + 1;
 537                 this = this->sibling;
 538         }
 539         for(;;) {
 540                 if (this)
 541                         tmp.end = (this == old) ?  this->end : this->start - 1;
 542                 else
 543                         tmp.end = root->end;
 544
 545                 if (tmp.end < tmp.start)
 546                         goto next;
 547
 548                 resource_clip(&tmp, constraint->min, constraint->max);
 549                 arch_remove_reservations(&tmp);
 550
 551                 /* Check for overflow after ALIGN() */
 552                 avail.start = ALIGN(tmp.start, constraint->align);
 553                 avail.end = tmp.end;
 554                 avail.flags = new->flags & ~IORESOURCE_UNSET;
 555                 if (avail.start >= tmp.start) {
 556                         alloc.flags = avail.flags;
 557                         alloc.start = constraint->alignf(constraint->alignf_data, &avail,
 558                                         size, constraint->align);
 559                         alloc.end = alloc.start + size - 1;
 560                         if (resource_contains(&avail, &alloc)) {
 561                                 new->start = alloc.start;
 562                                 new->end = alloc.end;
 563                                 return 0;
 564                         }
 565                 }
 566
 567 next:           if (!this || this->end == root->end)
 568                         break;
 569
 570                 if (this != old)
 571                         tmp.start = this->end + 1;
 572                 this = this->sibling;
 573         }
 574         return -EBUSY;
 575 }
 576
 577 /*
 578  * Find empty slot in the resource tree given range and alignment.
 579  */
 580 static int find_resource(struct resource *root, struct resource *new,
 581                         resource_size_t size,
 582                         struct resource_constraint  *constraint)
 583 {
 584         return  __find_resource(root, NULL, new, size, constraint);
 585 }
 586
 587 /**
 588  * reallocate_resource - allocate a slot in the resource tree given range & alignment.
 589  *      The resource will be relocated if the new size cannot be reallocated in the
 590  *      current location.
 591  *
 592  * @root: root resource descriptor
 593  * @old:  resource descriptor desired by caller
 594  * @newsize: new size of the resource descriptor
 595  * @constraint: the size and alignment constraints to be met.
 596  */
 597 static int reallocate_resource(struct resource *root, struct resource *old,
 598                         resource_size_t newsize,
 599                         struct resource_constraint  *constraint)
 600 {
 601         int err=0;
 602         struct resource new = *old;
 603         struct resource *conflict;
 604
 605         write_lock(&resource_lock);
 606
 607         if ((err = __find_resource(root, old, &new, newsize, constraint)))
 608                 goto out;
 609
 610         if (resource_contains(&new, old)) {
 611                 old->start = new.start;
 612                 old->end = new.end;
 613                 goto out;
 614         }
 615
 616         if (old->child) {
 617                 err = -EBUSY;
 618                 goto out;
 619         }
 620
 621         if (resource_contains(old, &new)) {
 622                 old->start = new.start;
 623                 old->end = new.end;
 624         } else {
 625                 __release_resource(old);
 626                 *old = new;
 627                 conflict = __request_resource(root, old);
 628                 BUG_ON(conflict);
 629         }
 630 out:
 631         write_unlock(&resource_lock);
 632         return err;
 633 }
 634
 635
 636 /**
 637  * allocate_resource - allocate empty slot in the resource tree given range & alignment.
 638  *      The resource will be reallocated with a new size if it was already allocated
 639  * @root: root resource descriptor
 640  * @new: resource descriptor desired by caller
 641  * @size: requested resource region size
 642  * @min: minimum boundary to allocate
 643  * @max: maximum boundary to allocate
 644  * @align: alignment requested, in bytes
 645  * @alignf: alignment function, optional, called if not NULL
 646  * @alignf_data: arbitrary data to pass to the @alignf function
 647  */
 648 int allocate_resource(struct resource *root, struct resource *new,
 649                       resource_size_t size, resource_size_t min,
 650                       resource_size_t max, resource_size_t align,
 651                       resource_size_t (*alignf)(void *,
 652                                                 const struct resource *,
 653                                                 resource_size_t,
 654                                                 resource_size_t),
 655                       void *alignf_data)
 656 {
 657         int err;
 658         struct resource_constraint constraint;
 659
 660         if (!alignf)
 661                 alignf = simple_align_resource;
 662
 663         constraint.min = min;
 664         constraint.max = max;
 665         constraint.align = align;
 666         constraint.alignf = alignf;
 667         constraint.alignf_data = alignf_data;
 668
 669         if ( new->parent ) {
 670                 /* resource is already allocated, try reallocating with
 671                    the new constraints */
 672                 return reallocate_resource(root, new, size, &constraint);
 673         }
 674
 675         write_lock(&resource_lock);
 676         err = find_resource(root, new, size, &constraint);
 677         if (err >= 0 && __request_resource(root, new))
 678                 err = -EBUSY;
 679         write_unlock(&resource_lock);
 680         return err;
 681 }
 682
 683 EXPORT_SYMBOL(allocate_resource);
 684
 685 /**
 686  * lookup_resource - find an existing resource by a resource start address
 687  * @root: root resource descriptor
 688  * @start: resource start address
 689  *
 690  * Returns a pointer to the resource if found, NULL otherwise
 691  */
 692 struct resource *lookup_resource(struct resource *root, resource_size_t start)
 693 {
 694         struct resource *res;
 695
 696         read_lock(&resource_lock);
 697         for (res = root->child; res; res = res->sibling) {
 698                 if (res->start == start)
 699                         break;
 700         }
 701         read_unlock(&resource_lock);
 702
 703         return res;
 704 }
 705
 706 /*
 707  * Insert a resource into the resource tree. If successful, return NULL,
 708  * otherwise return the conflicting resource (compare to __request_resource())
 709  */
 710 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 711 {
 712         struct resource *first, *next;
 713
 714         for (;; parent = first) {
 715                 first = __request_resource(parent, new);
 716                 if (!first)
 717                         return first;
 718
 719                 if (first == parent)
 720                         return first;
 721                 if (WARN_ON(first == new))      /* duplicated insertion */
 722                         return first;
 723
 724                 if ((first->start > new->start) || (first->end < new->end))
 725                         break;
 726                 if ((first->start == new->start) && (first->end == new->end))
 727                         break;
 728         }
 729
 730         for (next = first; ; next = next->sibling) {
 731                 /* Partial overlap? Bad, and unfixable */
 732                 if (next->start < new->start || next->end > new->end)
 733                         return next;
 734                 if (!next->sibling)
 735                         break;
 736                 if (next->sibling->start > new->end)
 737                         break;
 738         }
 739
 740         new->parent = parent;
 741         new->sibling = next->sibling;
 742         new->child = first;
 743
 744         next->sibling = NULL;
 745         for (next = first; next; next = next->sibling)
 746                 next->parent = new;
 747
 748         if (parent->child == first) {
 749                 parent->child = new;
 750         } else {
 751                 next = parent->child;
 752                 while (next->sibling != first)
 753                         next = next->sibling;
 754                 next->sibling = new;
 755         }
 756         return NULL;
 757 }
 758
 759 /**
 760  * insert_resource_conflict - Inserts resource in the resource tree
 761  * @parent: parent of the new resource
 762  * @new: new resource to insert
 763  *
 764  * Returns 0 on success, conflict resource if the resource can't be inserted.
 765  *
 766  * This function is equivalent to request_resource_conflict when no conflict
 767  * happens. If a conflict happens, and the conflicting resources
 768  * entirely fit within the range of the new resource, then the new
 769  * resource is inserted and the conflicting resources become children of
 770  * the new resource.
 771  */
 772 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 773 {
 774         struct resource *conflict;
 775
 776         write_lock(&resource_lock);
 777         conflict = __insert_resource(parent, new);
 778         write_unlock(&resource_lock);
 779         return conflict;
 780 }
 781
 782 /**
 783  * insert_resource - Inserts a resource in the resource tree
 784  * @parent: parent of the new resource
 785  * @new: new resource to insert
 786  *
 787  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 788  */
 789 int insert_resource(struct resource *parent, struct resource *new)
 790 {
 791         struct resource *conflict;
 792
 793         conflict = insert_resource_conflict(parent, new);
 794         return conflict ? -EBUSY : 0;
 795 }
 796
 797 /**
 798  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 799  * @root: root resource descriptor
 800  * @new: new resource to insert
 801  *
 802  * Insert a resource into the resource tree, possibly expanding it in order
 803  * to make it encompass any conflicting resources.
 804  */
 805 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 806 {
 807         if (new->parent)
 808                 return;
 809
 810         write_lock(&resource_lock);
 811         for (;;) {
 812                 struct resource *conflict;
 813
 814                 conflict = __insert_resource(root, new);
 815                 if (!conflict)
 816                         break;
 817                 if (conflict == root)
 818                         break;
 819
 820                 /* Ok, expand resource to cover the conflict, then try again .. */
 821                 if (conflict->start < new->start)
 822                         new->start = conflict->start;
 823                 if (conflict->end > new->end)
 824                         new->end = conflict->end;
 825
 826                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 827         }
 828         write_unlock(&resource_lock);
 829 }
 830
 831 static int __adjust_resource(struct resource *res, resource_size_t start,
 832                                 resource_size_t size)
 833 {
 834         struct resource *tmp, *parent = res->parent;
 835         resource_size_t end = start + size - 1;
 836         int result = -EBUSY;
 837
 838         if (!parent)
 839                 goto skip;
 840
 841         if ((start < parent->start) || (end > parent->end))
 842                 goto out;
 843
 844         if (res->sibling && (res->sibling->start <= end))
 845                 goto out;
 846
 847         tmp = parent->child;
 848         if (tmp != res) {
 849                 while (tmp->sibling != res)
 850                         tmp = tmp->sibling;
 851                 if (start <= tmp->end)
 852                         goto out;
 853         }
 854
 855 skip:
 856         for (tmp = res->child; tmp; tmp = tmp->sibling)
 857                 if ((tmp->start < start) || (tmp->end > end))
 858                         goto out;
 859
 860         res->start = start;
 861         res->end = end;
 862         result = 0;
 863
 864  out:
 865         return result;
 866 }
 867
 868 /**
 869  * adjust_resource - modify a resource's start and size
 870  * @res: resource to modify
 871  * @start: new start value
 872  * @size: new size
 873  *
 874  * Given an existing resource, change its start and size to match the
 875  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 876  * Existing children of the resource are assumed to be immutable.
 877  */
 878 int adjust_resource(struct resource *res, resource_size_t start,
 879                         resource_size_t size)
 880 {
 881         int result;
 882
 883         write_lock(&resource_lock);
 884         result = __adjust_resource(res, start, size);
 885         write_unlock(&resource_lock);
 886         return result;
 887 }
 888 EXPORT_SYMBOL(adjust_resource);
 889
 890 static void __init __reserve_region_with_split(struct resource *root,
 891                 resource_size_t start, resource_size_t end,
 892                 const char *name)
 893 {
 894         struct resource *parent = root;
 895         struct resource *conflict;
 896         struct resource *res = alloc_resource(GFP_ATOMIC);
 897         struct resource *next_res = NULL;
 898
 899         if (!res)
 900                 return;
 901
 902         res->name = name;
 903         res->start = start;
 904         res->end = end;
 905         res->flags = IORESOURCE_BUSY;
 906
 907         while (1) {
 908
 909                 conflict = __request_resource(parent, res);
 910                 if (!conflict) {
 911                         if (!next_res)
 912                                 break;
 913                         res = next_res;
 914                         next_res = NULL;
 915                         continue;
 916                 }
 917
 918                 /* conflict covered whole area */
 919                 if (conflict->start <= res->start &&
 920                                 conflict->end >= res->end) {
 921                         free_resource(res);
 922                         WARN_ON(next_res);
 923                         break;
 924                 }
 925
 926                 /* failed, split and try again */
 927                 if (conflict->start > res->start) {
 928                         end = res->end;
 929                         res->end = conflict->start - 1;
 930                         if (conflict->end < end) {
 931                                 next_res = alloc_resource(GFP_ATOMIC);
 932                                 if (!next_res) {
 933                                         free_resource(res);
 934                                         break;
 935                                 }
 936                                 next_res->name = name;
 937                                 next_res->start = conflict->end + 1;
 938                                 next_res->end = end;
 939                                 next_res->flags = IORESOURCE_BUSY;
 940                         }
 941                 } else {
 942                         res->start = conflict->end + 1;
 943                 }
 944         }
 945
 946 }
 947
 948 void __init reserve_region_with_split(struct resource *root,
 949                 resource_size_t start, resource_size_t end,
 950                 const char *name)
 951 {
 952         int abort = 0;
 953
 954         write_lock(&resource_lock);
 955         if (root->start > start || root->end < end) {
 956                 pr_err("requested range [0x%llx-0x%llx] not in root %pr\n",
 957                        (unsigned long long)start, (unsigned long long)end,
 958                        root);
 959                 if (start > root->end || end < root->start)
 960                         abort = 1;
 961                 else {
 962                         if (end > root->end)
 963                                 end = root->end;
 964                         if (start < root->start)
 965                                 start = root->start;
 966                         pr_err("fixing request to [0x%llx-0x%llx]\n",
 967                                (unsigned long long)start,
 968                                (unsigned long long)end);
 969                 }
 970                 dump_stack();
 971         }
 972         if (!abort)
 973                 __reserve_region_with_split(root, start, end, name);
 974         write_unlock(&resource_lock);
 975 }
 976
 977 /**
 978  * resource_alignment - calculate resource's alignment
 979  * @res: resource pointer
 980  *
 981  * Returns alignment on success, 0 (invalid alignment) on failure.
 982  */
 983 resource_size_t resource_alignment(struct resource *res)
 984 {
 985         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 986         case IORESOURCE_SIZEALIGN:
 987                 return resource_size(res);
 988         case IORESOURCE_STARTALIGN:
 989                 return res->start;
 990         default:
 991                 return 0;
 992         }
 993 }
 994
 995 /*
 996  * This is compatibility stuff for IO resources.
 997  *
 998  * Note how this, unlike the above, knows about
 999  * the IO flag meanings (busy etc).
1000  *
1001  * request_region creates a new busy region.
1002  *
1003  * check_region returns non-zero if the area is already busy.
1004  *
1005  * release_region releases a matching busy region.
1006  */
1007
1008 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
1009
1010 /**
1011  * __request_region - create a new busy resource region
1012  * @parent: parent resource descriptor
1013  * @start: resource start address
1014  * @n: resource region size
1015  * @name: reserving caller's ID string
1016  * @flags: IO resource flags
1017  */
1018 struct resource * __request_region(struct resource *parent,
1019                                    resource_size_t start, resource_size_t n,
1020                                    const char *name, int flags)
1021 {
1022         DECLARE_WAITQUEUE(wait, current);
1023         struct resource *res = alloc_resource(GFP_KERNEL);
1024
1025         if (!res)
1026                 return NULL;
1027
1028         res->name = name;
1029         res->start = start;
1030         res->end = start + n - 1;
1031         res->flags = resource_type(parent);
1032         res->flags |= IORESOURCE_BUSY | flags;
1033
1034         write_lock(&resource_lock);
1035
1036         for (;;) {
1037                 struct resource *conflict;
1038
1039                 conflict = __request_resource(parent, res);
1040                 if (!conflict)
1041                         break;
1042                 if (conflict != parent) {
1043                         parent = conflict;
1044                         if (!(conflict->flags & IORESOURCE_BUSY))
1045                                 continue;
1046                 }
1047                 if (conflict->flags & flags & IORESOURCE_MUXED) {
1048                         add_wait_queue(&muxed_resource_wait, &wait);
1049                         write_unlock(&resource_lock);
1050                         set_current_state(TASK_UNINTERRUPTIBLE);
1051                         schedule();
1052                         remove_wait_queue(&muxed_resource_wait, &wait);
1053                         write_lock(&resource_lock);
1054                         continue;
1055                 }
1056                 /* Uhhuh, that didn't work out.. */
1057                 free_resource(res);
1058                 res = NULL;
1059                 break;
1060         }
1061         write_unlock(&resource_lock);
1062         return res;
1063 }
1064 EXPORT_SYMBOL(__request_region);
1065
1066 /**
1067  * __check_region - check if a resource region is busy or free
1068  * @parent: parent resource descriptor
1069  * @start: resource start address
1070  * @n: resource region size
1071  *
1072  * Returns 0 if the region is free at the moment it is checked,
1073  * returns %-EBUSY if the region is busy.
1074  *
1075  * NOTE:
1076  * This function is deprecated because its use is racy.
1077  * Even if it returns 0, a subsequent call to request_region()
1078  * may fail because another driver etc. just allocated the region.
1079  * Do NOT use it.  It will be removed from the kernel.
1080  */
1081 int __check_region(struct resource *parent, resource_size_t start,
1082                         resource_size_t n)
1083 {
1084         struct resource * res;
1085
1086         res = __request_region(parent, start, n, "check-region", 0);
1087         if (!res)
1088                 return -EBUSY;
1089
1090         release_resource(res);
1091         free_resource(res);
1092         return 0;
1093 }
1094 EXPORT_SYMBOL(__check_region);
1095
1096 /**
1097  * __release_region - release a previously reserved resource region
1098  * @parent: parent resource descriptor
1099  * @start: resource start address
1100  * @n: resource region size
1101  *
1102  * The described resource region must match a currently busy region.
1103  */
1104 void __release_region(struct resource *parent, resource_size_t start,
1105                         resource_size_t n)
1106 {
1107         struct resource **p;
1108         resource_size_t end;
1109
1110         p = &parent->child;
1111         end = start + n - 1;
1112
1113         write_lock(&resource_lock);
1114
1115         for (;;) {
1116                 struct resource *res = *p;
1117
1118                 if (!res)
1119                         break;
1120                 if (res->start <= start && res->end >= end) {
1121                         if (!(res->flags & IORESOURCE_BUSY)) {
1122                                 p = &res->child;
1123                                 continue;
1124                         }
1125                         if (res->start != start || res->end != end)
1126                                 break;
1127                         *p = res->sibling;
1128                         write_unlock(&resource_lock);
1129                         if (res->flags & IORESOURCE_MUXED)
1130                                 wake_up(&muxed_resource_wait);
1131                         free_resource(res);
1132                         return;
1133                 }
1134                 p = &res->sibling;
1135         }
1136
1137         write_unlock(&resource_lock);
1138
1139         printk(KERN_WARNING "Trying to free nonexistent resource "
1140                 "<%016llx-%016llx>\n", (unsigned long long)start,
1141                 (unsigned long long)end);
1142 }
1143 EXPORT_SYMBOL(__release_region);
1144
1145 #ifdef CONFIG_MEMORY_HOTREMOVE
1146 /**
1147  * release_mem_region_adjustable - release a previously reserved memory region
1148  * @parent: parent resource descriptor
1149  * @start: resource start address
1150  * @size: resource region size
1151  *
1152  * This interface is intended for memory hot-delete.  The requested region
1153  * is released from a currently busy memory resource.  The requested region
1154  * must either match exactly or fit into a single busy resource entry.  In
1155  * the latter case, the remaining resource is adjusted accordingly.
1156  * Existing children of the busy memory resource must be immutable in the
1157  * request.
1158  *
1159  * Note:
1160  * - Additional release conditions, such as overlapping region, can be
1161  *   supported after they are confirmed as valid cases.
1162  * - When a busy memory resource gets split into two entries, the code
1163  *   assumes that all children remain in the lower address entry for
1164  *   simplicity.  Enhance this logic when necessary.
1165  */
1166 int release_mem_region_adjustable(struct resource *parent,
1167                         resource_size_t start, resource_size_t size)
1168 {
1169         struct resource **p;
1170         struct resource *res;
1171         struct resource *new_res;
1172         resource_size_t end;
1173         int ret = -EINVAL;
1174
1175         end = start + size - 1;
1176         if ((start < parent->start) || (end > parent->end))
1177                 return ret;
1178
1179         /* The alloc_resource() result gets checked later */
1180         new_res = alloc_resource(GFP_KERNEL);
1181
1182         p = &parent->child;
1183         write_lock(&resource_lock);
1184
1185         while ((res = *p)) {
1186                 if (res->start >= end)
1187                         break;
1188
1189                 /* look for the next resource if it does not fit into */
1190                 if (res->start > start || res->end < end) {
1191                         p = &res->sibling;
1192                         continue;
1193                 }
1194
1195                 if (!(res->flags & IORESOURCE_MEM))
1196                         break;
1197
1198                 if (!(res->flags & IORESOURCE_BUSY)) {
1199                         p = &res->child;
1200                         continue;
1201                 }
1202
1203                 /* found the target resource; let's adjust accordingly */
1204                 if (res->start == start && res->end == end) {
1205                         /* free the whole entry */
1206                         *p = res->sibling;
1207                         free_resource(res);
1208                         ret = 0;
1209                 } else if (res->start == start && res->end != end) {
1210                         /* adjust the start */
1211                         ret = __adjust_resource(res, end + 1,
1212                                                 res->end - end);
1213                 } else if (res->start != start && res->end == end) {
1214                         /* adjust the end */
1215                         ret = __adjust_resource(res, res->start,
1216                                                 start - res->start);
1217                 } else {
1218                         /* split into two entries */
1219                         if (!new_res) {
1220                                 ret = -ENOMEM;
1221                                 break;
1222                         }
1223                         new_res->name = res->name;
1224                         new_res->start = end + 1;
1225                         new_res->end = res->end;
1226                         new_res->flags = res->flags;
1227                         new_res->parent = res->parent;
1228                         new_res->sibling = res->sibling;
1229                         new_res->child = NULL;
1230
1231                         ret = __adjust_resource(res, res->start,
1232                                                 start - res->start);
1233                         if (ret)
1234                                 break;
1235                         res->sibling = new_res;
1236                         new_res = NULL;
1237                 }
1238
1239                 break;
1240         }
1241
1242         write_unlock(&resource_lock);
1243         free_resource(new_res);
1244         return ret;
1245 }
1246 #endif  /* CONFIG_MEMORY_HOTREMOVE */
1247
1248 /*
1249  * Managed region resource
1250  */
1251 struct region_devres {
1252         struct resource *parent;
1253         resource_size_t start;
1254         resource_size_t n;
1255 };
1256
1257 static void devm_region_release(struct device *dev, void *res)
1258 {
1259         struct region_devres *this = res;
1260
1261         __release_region(this->parent, this->start, this->n);
1262 }
1263
1264 static int devm_region_match(struct device *dev, void *res, void *match_data)
1265 {
1266         struct region_devres *this = res, *match = match_data;
1267
1268         return this->parent == match->parent &&
1269                 this->start == match->start && this->n == match->n;
1270 }
1271
1272 struct resource * __devm_request_region(struct device *dev,
1273                                 struct resource *parent, resource_size_t start,
1274                                 resource_size_t n, const char *name)
1275 {
1276         struct region_devres *dr = NULL;
1277         struct resource *res;
1278
1279         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
1280                           GFP_KERNEL);
1281         if (!dr)
1282                 return NULL;
1283
1284         dr->parent = parent;
1285         dr->start = start;
1286         dr->n = n;
1287
1288         res = __request_region(parent, start, n, name, 0);
1289         if (res)
1290                 devres_add(dev, dr);
1291         else
1292                 devres_free(dr);
1293
1294         return res;
1295 }
1296 EXPORT_SYMBOL(__devm_request_region);
1297
1298 void __devm_release_region(struct device *dev, struct resource *parent,
1299                            resource_size_t start, resource_size_t n)
1300 {
1301         struct region_devres match_data = { parent, start, n };
1302
1303         __release_region(parent, start, n);
1304         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
1305                                &match_data));
1306 }
1307 EXPORT_SYMBOL(__devm_release_region);
1308
1309 /*
1310  * Called from init/main.c to reserve IO ports.
1311  */
1312 #define MAXRESERVE 4
1313 static int __init reserve_setup(char *str)
1314 {
1315         static int reserved;
1316         static struct resource reserve[MAXRESERVE];
1317
1318         for (;;) {
1319                 unsigned int io_start, io_num;
1320                 int x = reserved;
1321
1322                 if (get_option (&str, &io_start) != 2)
1323                         break;
1324                 if (get_option (&str, &io_num)   == 0)
1325                         break;
1326                 if (x < MAXRESERVE) {
1327                         struct resource *res = reserve + x;
1328                         res->name = "reserved";
1329                         res->start = io_start;
1330                         res->end = io_start + io_num - 1;
1331                         res->flags = IORESOURCE_BUSY;
1332                         res->child = NULL;
1333                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
1334                                 reserved = x+1;
1335                 }
1336         }
1337         return 1;
1338 }
1339
1340 __setup("reserve=", reserve_setup);
1341
1342 /*
1343  * Check if the requested addr and size spans more than any slot in the
1344  * iomem resource tree.
1345  */
1346 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
1347 {
1348         struct resource *p = &iomem_resource;
1349         int err = 0;
1350         loff_t l;
1351
1352         read_lock(&resource_lock);
1353         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1354                 /*
1355                  * We can probably skip the resources without
1356                  * IORESOURCE_IO attribute?
1357                  */
1358                 if (p->start >= addr + size)
1359                         continue;
1360                 if (p->end < addr)
1361                         continue;
1362                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
1363                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
1364                         continue;
1365                 /*
1366                  * if a resource is "BUSY", it's not a hardware resource
1367                  * but a driver mapping of such a resource; we don't want
1368                  * to warn for those; some drivers legitimately map only
1369                  * partial hardware resources. (example: vesafb)
1370                  */
1371                 if (p->flags & IORESOURCE_BUSY)
1372                         continue;
1373
1374                 printk(KERN_WARNING "resource sanity check: requesting [mem %#010llx-%#010llx], which spans more than %s %pR\n",
1375                        (unsigned long long)addr,
1376                        (unsigned long long)(addr + size - 1),
1377                        p->name, p);
1378                 err = -1;
1379                 break;
1380         }
1381         read_unlock(&resource_lock);
1382
1383         return err;
1384 }
1385
1386 #ifdef CONFIG_STRICT_DEVMEM
1387 static int strict_iomem_checks = 1;
1388 #else
1389 static int strict_iomem_checks;
1390 #endif
1391
1392 /*
1393  * check if an address is reserved in the iomem resource tree
1394  * returns 1 if reserved, 0 if not reserved.
1395  */
1396 int iomem_is_exclusive(u64 addr)
1397 {
1398         struct resource *p = &iomem_resource;
1399         int err = 0;
1400         loff_t l;
1401         int size = PAGE_SIZE;
1402
1403         if (!strict_iomem_checks)
1404                 return 0;
1405
1406         addr = addr & PAGE_MASK;
1407
1408         read_lock(&resource_lock);
1409         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
1410                 /*
1411                  * We can probably skip the resources without
1412                  * IORESOURCE_IO attribute?
1413                  */
1414                 if (p->start >= addr + size)
1415                         break;
1416                 if (p->end < addr)
1417                         continue;
1418                 if (p->flags & IORESOURCE_BUSY &&
1419                      p->flags & IORESOURCE_EXCLUSIVE) {
1420                         err = 1;
1421                         break;
1422                 }
1423         }
1424         read_unlock(&resource_lock);
1425
1426         return err;
1427 }
1428
1429 static int __init strict_iomem(char *str)
1430 {
1431         if (strstr(str, "relaxed"))
1432                 strict_iomem_checks = 0;
1433         if (strstr(str, "strict"))
1434                 strict_iomem_checks = 1;
1435         return 1;
1436 }
1437
1438 __setup("iomem=", strict_iomem);