kernel/resource.c

   1 /*
   2  *      linux/kernel/resource.c
   3  *
   4  * Copyright (C) 1999   Linus Torvalds
   5  * Copyright (C) 1999   Martin Mares <mj@ucw.cz>
   6  *
   7  * Arbitrary resource management.
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/errno.h>
  12 #include <linux/ioport.h>
  13 #include <linux/init.h>
  14 #include <linux/slab.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/fs.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/device.h>
  20 #include <asm/io.h>
  21
  22
  23 struct resource ioport_resource = {
  24         .name   = "PCI IO",
  25         .start  = 0,
  26         .end    = IO_SPACE_LIMIT,
  27         .flags  = IORESOURCE_IO,
  28 };
  29 EXPORT_SYMBOL(ioport_resource);
  30
  31 struct resource iomem_resource = {
  32         .name   = "PCI mem",
  33         .start  = 0,
  34         .end    = -1,
  35         .flags  = IORESOURCE_MEM,
  36 };
  37 EXPORT_SYMBOL(iomem_resource);
  38
  39 static DEFINE_RWLOCK(resource_lock);
  40
  41 #ifdef CONFIG_PROC_FS
  42
  43 enum { MAX_IORES_LEVEL = 5 };
  44
  45 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  46 {
  47         struct resource *p = v;
  48         (*pos)++;
  49         if (p->child)
  50                 return p->child;
  51         while (!p->sibling && p->parent)
  52                 p = p->parent;
  53         return p->sibling;
  54 }
  55
  56 static void *r_start(struct seq_file *m, loff_t *pos)
  57         __acquires(resource_lock)
  58 {
  59         struct resource *p = m->private;
  60         loff_t l = 0;
  61         read_lock(&resource_lock);
  62         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  63                 ;
  64         return p;
  65 }
  66
  67 static void r_stop(struct seq_file *m, void *v)
  68         __releases(resource_lock)
  69 {
  70         read_unlock(&resource_lock);
  71 }
  72
  73 static int r_show(struct seq_file *m, void *v)
  74 {
  75         struct resource *root = m->private;
  76         struct resource *r = v, *p;
  77         int width = root->end < 0x10000 ? 4 : 8;
  78         int depth;
  79
  80         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
  81                 if (p->parent == root)
  82                         break;
  83         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
  84                         depth * 2, "",
  85                         width, (unsigned long long) r->start,
  86                         width, (unsigned long long) r->end,
  87                         r->name ? r->name : "<BAD>");
  88         return 0;
  89 }
  90
  91 static const struct seq_operations resource_op = {
  92         .start  = r_start,
  93         .next   = r_next,
  94         .stop   = r_stop,
  95         .show   = r_show,
  96 };
  97
  98 static int ioports_open(struct inode *inode, struct file *file)
  99 {
 100         int res = seq_open(file, &resource_op);
 101         if (!res) {
 102                 struct seq_file *m = file->private_data;
 103                 m->private = &ioport_resource;
 104         }
 105         return res;
 106 }
 107
 108 static int iomem_open(struct inode *inode, struct file *file)
 109 {
 110         int res = seq_open(file, &resource_op);
 111         if (!res) {
 112                 struct seq_file *m = file->private_data;
 113                 m->private = &iomem_resource;
 114         }
 115         return res;
 116 }
 117
 118 static const struct file_operations proc_ioports_operations = {
 119         .open           = ioports_open,
 120         .read           = seq_read,
 121         .llseek         = seq_lseek,
 122         .release        = seq_release,
 123 };
 124
 125 static const struct file_operations proc_iomem_operations = {
 126         .open           = iomem_open,
 127         .read           = seq_read,
 128         .llseek         = seq_lseek,
 129         .release        = seq_release,
 130 };
 131
 132 static int __init ioresources_init(void)
 133 {
 134         proc_create("ioports", 0, NULL, &proc_ioports_operations);
 135         proc_create("iomem", 0, NULL, &proc_iomem_operations);
 136         return 0;
 137 }
 138 __initcall(ioresources_init);
 139
 140 #endif /* CONFIG_PROC_FS */
 141
 142 /* Return the conflict entry if you can't request it */
 143 static struct resource * __request_resource(struct resource *root, struct resource *new)
 144 {
 145         resource_size_t start = new->start;
 146         resource_size_t end = new->end;
 147         struct resource *tmp, **p;
 148
 149         if (end < start)
 150                 return root;
 151         if (start < root->start)
 152                 return root;
 153         if (end > root->end)
 154                 return root;
 155         p = &root->child;
 156         for (;;) {
 157                 tmp = *p;
 158                 if (!tmp || tmp->start > end) {
 159                         new->sibling = tmp;
 160                         *p = new;
 161                         new->parent = root;
 162                         return NULL;
 163                 }
 164                 p = &tmp->sibling;
 165                 if (tmp->end < start)
 166                         continue;
 167                 return tmp;
 168         }
 169 }
 170
 171 static int __release_resource(struct resource *old)
 172 {
 173         struct resource *tmp, **p;
 174
 175         p = &old->parent->child;
 176         for (;;) {
 177                 tmp = *p;
 178                 if (!tmp)
 179                         break;
 180                 if (tmp == old) {
 181                         *p = tmp->sibling;
 182                         old->parent = NULL;
 183                         return 0;
 184                 }
 185                 p = &tmp->sibling;
 186         }
 187         return -EINVAL;
 188 }
 189
 190 /**
 191  * request_resource - request and reserve an I/O or memory resource
 192  * @root: root resource descriptor
 193  * @new: resource descriptor desired by caller
 194  *
 195  * Returns 0 for success, negative error code on error.
 196  */
 197 int request_resource(struct resource *root, struct resource *new)
 198 {
 199         struct resource *conflict;
 200
 201         write_lock(&resource_lock);
 202         conflict = __request_resource(root, new);
 203         write_unlock(&resource_lock);
 204         return conflict ? -EBUSY : 0;
 205 }
 206
 207 EXPORT_SYMBOL(request_resource);
 208
 209 /**
 210  * release_resource - release a previously reserved resource
 211  * @old: resource pointer
 212  */
 213 int release_resource(struct resource *old)
 214 {
 215         int retval;
 216
 217         write_lock(&resource_lock);
 218         retval = __release_resource(old);
 219         write_unlock(&resource_lock);
 220         return retval;
 221 }
 222
 223 EXPORT_SYMBOL(release_resource);
 224
 225 #if defined(CONFIG_MEMORY_HOTPLUG) && !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 226 /*
 227  * Finds the lowest memory reosurce exists within [res->start.res->end)
 228  * the caller must specify res->start, res->end, res->flags.
 229  * If found, returns 0, res is overwritten, if not found, returns -1.
 230  */
 231 static int find_next_system_ram(struct resource *res)
 232 {
 233         resource_size_t start, end;
 234         struct resource *p;
 235
 236         BUG_ON(!res);
 237
 238         start = res->start;
 239         end = res->end;
 240         BUG_ON(start >= end);
 241
 242         read_lock(&resource_lock);
 243         for (p = iomem_resource.child; p ; p = p->sibling) {
 244                 /* system ram is just marked as IORESOURCE_MEM */
 245                 if (p->flags != res->flags)
 246                         continue;
 247                 if (p->start > end) {
 248                         p = NULL;
 249                         break;
 250                 }
 251                 if ((p->end >= start) && (p->start < end))
 252                         break;
 253         }
 254         read_unlock(&resource_lock);
 255         if (!p)
 256                 return -1;
 257         /* copy data */
 258         if (res->start < p->start)
 259                 res->start = p->start;
 260         if (res->end > p->end)
 261                 res->end = p->end;
 262         return 0;
 263 }
 264 int
 265 walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
 266                         int (*func)(unsigned long, unsigned long, void *))
 267 {
 268         struct resource res;
 269         unsigned long pfn, len;
 270         u64 orig_end;
 271         int ret = -1;
 272         res.start = (u64) start_pfn << PAGE_SHIFT;
 273         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 274         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 275         orig_end = res.end;
 276         while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
 277                 pfn = (unsigned long)(res.start >> PAGE_SHIFT);
 278                 len = (unsigned long)((res.end + 1 - res.start) >> PAGE_SHIFT);
 279                 ret = (*func)(pfn, len, arg);
 280                 if (ret)
 281                         break;
 282                 res.start = res.end + 1;
 283                 res.end = orig_end;
 284         }
 285         return ret;
 286 }
 287
 288 #endif
 289
 290 /*
 291  * Find empty slot in the resource tree given range and alignment.
 292  */
 293 static int find_resource(struct resource *root, struct resource *new,
 294                          resource_size_t size, resource_size_t min,
 295                          resource_size_t max, resource_size_t align,
 296                          void (*alignf)(void *, struct resource *,
 297                                         resource_size_t, resource_size_t),
 298                          void *alignf_data)
 299 {
 300         struct resource *this = root->child;
 301
 302         new->start = root->start;
 303         /*
 304          * Skip past an allocated resource that starts at 0, since the assignment
 305          * of this->start - 1 to new->end below would cause an underflow.
 306          */
 307         if (this && this->start == 0) {
 308                 new->start = this->end + 1;
 309                 this = this->sibling;
 310         }
 311         for(;;) {
 312                 if (this)
 313                         new->end = this->start - 1;
 314                 else
 315                         new->end = root->end;
 316                 if (new->start < min)
 317                         new->start = min;
 318                 if (new->end > max)
 319                         new->end = max;
 320                 new->start = ALIGN(new->start, align);
 321                 if (alignf)
 322                         alignf(alignf_data, new, size, align);
 323                 if (new->start < new->end && new->end - new->start >= size - 1) {
 324                         new->end = new->start + size - 1;
 325                         return 0;
 326                 }
 327                 if (!this)
 328                         break;
 329                 new->start = this->end + 1;
 330                 this = this->sibling;
 331         }
 332         return -EBUSY;
 333 }
 334
 335 /**
 336  * allocate_resource - allocate empty slot in the resource tree given range & alignment
 337  * @root: root resource descriptor
 338  * @new: resource descriptor desired by caller
 339  * @size: requested resource region size
 340  * @min: minimum size to allocate
 341  * @max: maximum size to allocate
 342  * @align: alignment requested, in bytes
 343  * @alignf: alignment function, optional, called if not NULL
 344  * @alignf_data: arbitrary data to pass to the @alignf function
 345  */
 346 int allocate_resource(struct resource *root, struct resource *new,
 347                       resource_size_t size, resource_size_t min,
 348                       resource_size_t max, resource_size_t align,
 349                       void (*alignf)(void *, struct resource *,
 350                                      resource_size_t, resource_size_t),
 351                       void *alignf_data)
 352 {
 353         int err;
 354
 355         write_lock(&resource_lock);
 356         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 357         if (err >= 0 && __request_resource(root, new))
 358                 err = -EBUSY;
 359         write_unlock(&resource_lock);
 360         return err;
 361 }
 362
 363 EXPORT_SYMBOL(allocate_resource);
 364
 365 /**
 366  * insert_resource - Inserts a resource in the resource tree
 367  * @parent: parent of the new resource
 368  * @new: new resource to insert
 369  *
 370  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 371  *
 372  * This function is equivalent to request_resource when no conflict
 373  * happens. If a conflict happens, and the conflicting resources
 374  * entirely fit within the range of the new resource, then the new
 375  * resource is inserted and the conflicting resources become children of
 376  * the new resource.
 377  */
 378 int insert_resource(struct resource *parent, struct resource *new)
 379 {
 380         int result;
 381         struct resource *first, *next;
 382
 383         write_lock(&resource_lock);
 384
 385         for (;; parent = first) {
 386                 result = 0;
 387                 first = __request_resource(parent, new);
 388                 if (!first)
 389                         goto out;
 390
 391                 result = -EBUSY;
 392                 if (first == parent)
 393                         goto out;
 394
 395                 if ((first->start > new->start) || (first->end < new->end))
 396                         break;
 397                 if ((first->start == new->start) && (first->end == new->end))
 398                         break;
 399         }
 400
 401         for (next = first; ; next = next->sibling) {
 402                 /* Partial overlap? Bad, and unfixable */
 403                 if (next->start < new->start || next->end > new->end)
 404                         goto out;
 405                 if (!next->sibling)
 406                         break;
 407                 if (next->sibling->start > new->end)
 408                         break;
 409         }
 410
 411         result = 0;
 412
 413         new->parent = parent;
 414         new->sibling = next->sibling;
 415         new->child = first;
 416
 417         next->sibling = NULL;
 418         for (next = first; next; next = next->sibling)
 419                 next->parent = new;
 420
 421         if (parent->child == first) {
 422                 parent->child = new;
 423         } else {
 424                 next = parent->child;
 425                 while (next->sibling != first)
 426                         next = next->sibling;
 427                 next->sibling = new;
 428         }
 429
 430  out:
 431         write_unlock(&resource_lock);
 432         return result;
 433 }
 434
 435 /**
 436  * adjust_resource - modify a resource's start and size
 437  * @res: resource to modify
 438  * @start: new start value
 439  * @size: new size
 440  *
 441  * Given an existing resource, change its start and size to match the
 442  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 443  * Existing children of the resource are assumed to be immutable.
 444  */
 445 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 446 {
 447         struct resource *tmp, *parent = res->parent;
 448         resource_size_t end = start + size - 1;
 449         int result = -EBUSY;
 450
 451         write_lock(&resource_lock);
 452
 453         if ((start < parent->start) || (end > parent->end))
 454                 goto out;
 455
 456         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 457                 if ((tmp->start < start) || (tmp->end > end))
 458                         goto out;
 459         }
 460
 461         if (res->sibling && (res->sibling->start <= end))
 462                 goto out;
 463
 464         tmp = parent->child;
 465         if (tmp != res) {
 466                 while (tmp->sibling != res)
 467                         tmp = tmp->sibling;
 468                 if (start <= tmp->end)
 469                         goto out;
 470         }
 471
 472         res->start = start;
 473         res->end = end;
 474         result = 0;
 475
 476  out:
 477         write_unlock(&resource_lock);
 478         return result;
 479 }
 480
 481 EXPORT_SYMBOL(adjust_resource);
 482
 483 /**
 484  * resource_alignment - calculate resource's alignment
 485  * @res: resource pointer
 486  *
 487  * Returns alignment on success, 0 (invalid alignment) on failure.
 488  */
 489 resource_size_t resource_alignment(struct resource *res)
 490 {
 491         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 492         case IORESOURCE_SIZEALIGN:
 493                 return res->end - res->start + 1;
 494         case IORESOURCE_STARTALIGN:
 495                 return res->start;
 496         default:
 497                 return 0;
 498         }
 499 }
 500
 501 /*
 502  * This is compatibility stuff for IO resources.
 503  *
 504  * Note how this, unlike the above, knows about
 505  * the IO flag meanings (busy etc).
 506  *
 507  * request_region creates a new busy region.
 508  *
 509  * check_region returns non-zero if the area is already busy.
 510  *
 511  * release_region releases a matching busy region.
 512  */
 513
 514 /**
 515  * __request_region - create a new busy resource region
 516  * @parent: parent resource descriptor
 517  * @start: resource start address
 518  * @n: resource region size
 519  * @name: reserving caller's ID string
 520  */
 521 struct resource * __request_region(struct resource *parent,
 522                                    resource_size_t start, resource_size_t n,
 523                                    const char *name)
 524 {
 525         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 526
 527         if (res) {
 528                 res->name = name;
 529                 res->start = start;
 530                 res->end = start + n - 1;
 531                 res->flags = IORESOURCE_BUSY;
 532
 533                 write_lock(&resource_lock);
 534
 535                 for (;;) {
 536                         struct resource *conflict;
 537
 538                         conflict = __request_resource(parent, res);
 539                         if (!conflict)
 540                                 break;
 541                         if (conflict != parent) {
 542                                 parent = conflict;
 543                                 if (!(conflict->flags & IORESOURCE_BUSY))
 544                                         continue;
 545                         }
 546
 547                         /* Uhhuh, that didn't work out.. */
 548                         kfree(res);
 549                         res = NULL;
 550                         break;
 551                 }
 552                 write_unlock(&resource_lock);
 553         }
 554         return res;
 555 }
 556 EXPORT_SYMBOL(__request_region);
 557
 558 /**
 559  * __check_region - check if a resource region is busy or free
 560  * @parent: parent resource descriptor
 561  * @start: resource start address
 562  * @n: resource region size
 563  *
 564  * Returns 0 if the region is free at the moment it is checked,
 565  * returns %-EBUSY if the region is busy.
 566  *
 567  * NOTE:
 568  * This function is deprecated because its use is racy.
 569  * Even if it returns 0, a subsequent call to request_region()
 570  * may fail because another driver etc. just allocated the region.
 571  * Do NOT use it.  It will be removed from the kernel.
 572  */
 573 int __check_region(struct resource *parent, resource_size_t start,
 574                         resource_size_t n)
 575 {
 576         struct resource * res;
 577
 578         res = __request_region(parent, start, n, "check-region");
 579         if (!res)
 580                 return -EBUSY;
 581
 582         release_resource(res);
 583         kfree(res);
 584         return 0;
 585 }
 586 EXPORT_SYMBOL(__check_region);
 587
 588 /**
 589  * __release_region - release a previously reserved resource region
 590  * @parent: parent resource descriptor
 591  * @start: resource start address
 592  * @n: resource region size
 593  *
 594  * The described resource region must match a currently busy region.
 595  */
 596 void __release_region(struct resource *parent, resource_size_t start,
 597                         resource_size_t n)
 598 {
 599         struct resource **p;
 600         resource_size_t end;
 601
 602         p = &parent->child;
 603         end = start + n - 1;
 604
 605         write_lock(&resource_lock);
 606
 607         for (;;) {
 608                 struct resource *res = *p;
 609
 610                 if (!res)
 611                         break;
 612                 if (res->start <= start && res->end >= end) {
 613                         if (!(res->flags & IORESOURCE_BUSY)) {
 614                                 p = &res->child;
 615                                 continue;
 616                         }
 617                         if (res->start != start || res->end != end)
 618                                 break;
 619                         *p = res->sibling;
 620                         write_unlock(&resource_lock);
 621                         kfree(res);
 622                         return;
 623                 }
 624                 p = &res->sibling;
 625         }
 626
 627         write_unlock(&resource_lock);
 628
 629         printk(KERN_WARNING "Trying to free nonexistent resource "
 630                 "<%016llx-%016llx>\n", (unsigned long long)start,
 631                 (unsigned long long)end);
 632 }
 633 EXPORT_SYMBOL(__release_region);
 634
 635 /*
 636  * Managed region resource
 637  */
 638 struct region_devres {
 639         struct resource *parent;
 640         resource_size_t start;
 641         resource_size_t n;
 642 };
 643
 644 static void devm_region_release(struct device *dev, void *res)
 645 {
 646         struct region_devres *this = res;
 647
 648         __release_region(this->parent, this->start, this->n);
 649 }
 650
 651 static int devm_region_match(struct device *dev, void *res, void *match_data)
 652 {
 653         struct region_devres *this = res, *match = match_data;
 654
 655         return this->parent == match->parent &&
 656                 this->start == match->start && this->n == match->n;
 657 }
 658
 659 struct resource * __devm_request_region(struct device *dev,
 660                                 struct resource *parent, resource_size_t start,
 661                                 resource_size_t n, const char *name)
 662 {
 663         struct region_devres *dr = NULL;
 664         struct resource *res;
 665
 666         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 667                           GFP_KERNEL);
 668         if (!dr)
 669                 return NULL;
 670
 671         dr->parent = parent;
 672         dr->start = start;
 673         dr->n = n;
 674
 675         res = __request_region(parent, start, n, name);
 676         if (res)
 677                 devres_add(dev, dr);
 678         else
 679                 devres_free(dr);
 680
 681         return res;
 682 }
 683 EXPORT_SYMBOL(__devm_request_region);
 684
 685 void __devm_release_region(struct device *dev, struct resource *parent,
 686                            resource_size_t start, resource_size_t n)
 687 {
 688         struct region_devres match_data = { parent, start, n };
 689
 690         __release_region(parent, start, n);
 691         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
 692                                &match_data));
 693 }
 694 EXPORT_SYMBOL(__devm_release_region);
 695
 696 /*
 697  * Called from init/main.c to reserve IO ports.
 698  */
 699 #define MAXRESERVE 4
 700 static int __init reserve_setup(char *str)
 701 {
 702         static int reserved;
 703         static struct resource reserve[MAXRESERVE];
 704
 705         for (;;) {
 706                 int io_start, io_num;
 707                 int x = reserved;
 708
 709                 if (get_option (&str, &io_start) != 2)
 710                         break;
 711                 if (get_option (&str, &io_num)   == 0)
 712                         break;
 713                 if (x < MAXRESERVE) {
 714                         struct resource *res = reserve + x;
 715                         res->name = "reserved";
 716                         res->start = io_start;
 717                         res->end = io_start + io_num - 1;
 718                         res->flags = IORESOURCE_BUSY;
 719                         res->child = NULL;
 720                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 721                                 reserved = x+1;
 722                 }
 723         }
 724         return 1;
 725 }
 726
 727 __setup("reserve=", reserve_setup);