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         struct proc_dir_entry *entry;
 135
 136         entry = create_proc_entry("ioports", 0, NULL);
 137         if (entry)
 138                 entry->proc_fops = &proc_ioports_operations;
 139         entry = create_proc_entry("iomem", 0, NULL);
 140         if (entry)
 141                 entry->proc_fops = &proc_iomem_operations;
 142         return 0;
 143 }
 144 __initcall(ioresources_init);
 145
 146 #endif /* CONFIG_PROC_FS */
 147
 148 /* Return the conflict entry if you can't request it */
 149 static struct resource * __request_resource(struct resource *root, struct resource *new)
 150 {
 151         resource_size_t start = new->start;
 152         resource_size_t end = new->end;
 153         struct resource *tmp, **p;
 154
 155         if (end < start)
 156                 return root;
 157         if (start < root->start)
 158                 return root;
 159         if (end > root->end)
 160                 return root;
 161         p = &root->child;
 162         for (;;) {
 163                 tmp = *p;
 164                 if (!tmp || tmp->start > end) {
 165                         new->sibling = tmp;
 166                         *p = new;
 167                         new->parent = root;
 168                         return NULL;
 169                 }
 170                 p = &tmp->sibling;
 171                 if (tmp->end < start)
 172                         continue;
 173                 return tmp;
 174         }
 175 }
 176
 177 static int __release_resource(struct resource *old)
 178 {
 179         struct resource *tmp, **p;
 180
 181         p = &old->parent->child;
 182         for (;;) {
 183                 tmp = *p;
 184                 if (!tmp)
 185                         break;
 186                 if (tmp == old) {
 187                         *p = tmp->sibling;
 188                         old->parent = NULL;
 189                         return 0;
 190                 }
 191                 p = &tmp->sibling;
 192         }
 193         return -EINVAL;
 194 }
 195
 196 /**
 197  * request_resource - request and reserve an I/O or memory resource
 198  * @root: root resource descriptor
 199  * @new: resource descriptor desired by caller
 200  *
 201  * Returns 0 for success, negative error code on error.
 202  */
 203 int request_resource(struct resource *root, struct resource *new)
 204 {
 205         struct resource *conflict;
 206
 207         write_lock(&resource_lock);
 208         conflict = __request_resource(root, new);
 209         write_unlock(&resource_lock);
 210         return conflict ? -EBUSY : 0;
 211 }
 212
 213 EXPORT_SYMBOL(request_resource);
 214
 215 /**
 216  * release_resource - release a previously reserved resource
 217  * @old: resource pointer
 218  */
 219 int release_resource(struct resource *old)
 220 {
 221         int retval;
 222
 223         write_lock(&resource_lock);
 224         retval = __release_resource(old);
 225         write_unlock(&resource_lock);
 226         return retval;
 227 }
 228
 229 EXPORT_SYMBOL(release_resource);
 230
 231 #ifdef CONFIG_MEMORY_HOTPLUG
 232 /*
 233  * Finds the lowest memory reosurce exists within [res->start.res->end)
 234  * the caller must specify res->start, res->end, res->flags.
 235  * If found, returns 0, res is overwritten, if not found, returns -1.
 236  */
 237 int find_next_system_ram(struct resource *res)
 238 {
 239         resource_size_t start, end;
 240         struct resource *p;
 241
 242         BUG_ON(!res);
 243
 244         start = res->start;
 245         end = res->end;
 246         BUG_ON(start >= end);
 247
 248         read_lock(&resource_lock);
 249         for (p = iomem_resource.child; p ; p = p->sibling) {
 250                 /* system ram is just marked as IORESOURCE_MEM */
 251                 if (p->flags != res->flags)
 252                         continue;
 253                 if (p->start > end) {
 254                         p = NULL;
 255                         break;
 256                 }
 257                 if ((p->end >= start) && (p->start < end))
 258                         break;
 259         }
 260         read_unlock(&resource_lock);
 261         if (!p)
 262                 return -1;
 263         /* copy data */
 264         if (res->start < p->start)
 265                 res->start = p->start;
 266         if (res->end > p->end)
 267                 res->end = p->end;
 268         return 0;
 269 }
 270 #endif
 271
 272 /*
 273  * Find empty slot in the resource tree given range and alignment.
 274  */
 275 static int find_resource(struct resource *root, struct resource *new,
 276                          resource_size_t size, resource_size_t min,
 277                          resource_size_t max, resource_size_t align,
 278                          void (*alignf)(void *, struct resource *,
 279                                         resource_size_t, resource_size_t),
 280                          void *alignf_data)
 281 {
 282         struct resource *this = root->child;
 283
 284         new->start = root->start;
 285         /*
 286          * Skip past an allocated resource that starts at 0, since the assignment
 287          * of this->start - 1 to new->end below would cause an underflow.
 288          */
 289         if (this && this->start == 0) {
 290                 new->start = this->end + 1;
 291                 this = this->sibling;
 292         }
 293         for(;;) {
 294                 if (this)
 295                         new->end = this->start - 1;
 296                 else
 297                         new->end = root->end;
 298                 if (new->start < min)
 299                         new->start = min;
 300                 if (new->end > max)
 301                         new->end = max;
 302                 new->start = ALIGN(new->start, align);
 303                 if (alignf)
 304                         alignf(alignf_data, new, size, align);
 305                 if (new->start < new->end && new->end - new->start >= size - 1) {
 306                         new->end = new->start + size - 1;
 307                         return 0;
 308                 }
 309                 if (!this)
 310                         break;
 311                 new->start = this->end + 1;
 312                 this = this->sibling;
 313         }
 314         return -EBUSY;
 315 }
 316
 317 /**
 318  * allocate_resource - allocate empty slot in the resource tree given range & alignment
 319  * @root: root resource descriptor
 320  * @new: resource descriptor desired by caller
 321  * @size: requested resource region size
 322  * @min: minimum size to allocate
 323  * @max: maximum size to allocate
 324  * @align: alignment requested, in bytes
 325  * @alignf: alignment function, optional, called if not NULL
 326  * @alignf_data: arbitrary data to pass to the @alignf function
 327  */
 328 int allocate_resource(struct resource *root, struct resource *new,
 329                       resource_size_t size, resource_size_t min,
 330                       resource_size_t max, resource_size_t align,
 331                       void (*alignf)(void *, struct resource *,
 332                                      resource_size_t, resource_size_t),
 333                       void *alignf_data)
 334 {
 335         int err;
 336
 337         write_lock(&resource_lock);
 338         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 339         if (err >= 0 && __request_resource(root, new))
 340                 err = -EBUSY;
 341         write_unlock(&resource_lock);
 342         return err;
 343 }
 344
 345 EXPORT_SYMBOL(allocate_resource);
 346
 347 /**
 348  * insert_resource - Inserts a resource in the resource tree
 349  * @parent: parent of the new resource
 350  * @new: new resource to insert
 351  *
 352  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 353  *
 354  * This function is equivalent to request_resource when no conflict
 355  * happens. If a conflict happens, and the conflicting resources
 356  * entirely fit within the range of the new resource, then the new
 357  * resource is inserted and the conflicting resources become children of
 358  * the new resource.
 359  */
 360 int insert_resource(struct resource *parent, struct resource *new)
 361 {
 362         int result;
 363         struct resource *first, *next;
 364
 365         write_lock(&resource_lock);
 366
 367         for (;; parent = first) {
 368                 result = 0;
 369                 first = __request_resource(parent, new);
 370                 if (!first)
 371                         goto out;
 372
 373                 result = -EBUSY;
 374                 if (first == parent)
 375                         goto out;
 376
 377                 if ((first->start > new->start) || (first->end < new->end))
 378                         break;
 379                 if ((first->start == new->start) && (first->end == new->end))
 380                         break;
 381         }
 382
 383         for (next = first; ; next = next->sibling) {
 384                 /* Partial overlap? Bad, and unfixable */
 385                 if (next->start < new->start || next->end > new->end)
 386                         goto out;
 387                 if (!next->sibling)
 388                         break;
 389                 if (next->sibling->start > new->end)
 390                         break;
 391         }
 392
 393         result = 0;
 394
 395         new->parent = parent;
 396         new->sibling = next->sibling;
 397         new->child = first;
 398
 399         next->sibling = NULL;
 400         for (next = first; next; next = next->sibling)
 401                 next->parent = new;
 402
 403         if (parent->child == first) {
 404                 parent->child = new;
 405         } else {
 406                 next = parent->child;
 407                 while (next->sibling != first)
 408                         next = next->sibling;
 409                 next->sibling = new;
 410         }
 411
 412  out:
 413         write_unlock(&resource_lock);
 414         return result;
 415 }
 416
 417 /**
 418  * adjust_resource - modify a resource's start and size
 419  * @res: resource to modify
 420  * @start: new start value
 421  * @size: new size
 422  *
 423  * Given an existing resource, change its start and size to match the
 424  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 425  * Existing children of the resource are assumed to be immutable.
 426  */
 427 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 428 {
 429         struct resource *tmp, *parent = res->parent;
 430         resource_size_t end = start + size - 1;
 431         int result = -EBUSY;
 432
 433         write_lock(&resource_lock);
 434
 435         if ((start < parent->start) || (end > parent->end))
 436                 goto out;
 437
 438         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 439                 if ((tmp->start < start) || (tmp->end > end))
 440                         goto out;
 441         }
 442
 443         if (res->sibling && (res->sibling->start <= end))
 444                 goto out;
 445
 446         tmp = parent->child;
 447         if (tmp != res) {
 448                 while (tmp->sibling != res)
 449                         tmp = tmp->sibling;
 450                 if (start <= tmp->end)
 451                         goto out;
 452         }
 453
 454         res->start = start;
 455         res->end = end;
 456         result = 0;
 457
 458  out:
 459         write_unlock(&resource_lock);
 460         return result;
 461 }
 462
 463 EXPORT_SYMBOL(adjust_resource);
 464
 465 /*
 466  * This is compatibility stuff for IO resources.
 467  *
 468  * Note how this, unlike the above, knows about
 469  * the IO flag meanings (busy etc).
 470  *
 471  * request_region creates a new busy region.
 472  *
 473  * check_region returns non-zero if the area is already busy.
 474  *
 475  * release_region releases a matching busy region.
 476  */
 477
 478 /**
 479  * __request_region - create a new busy resource region
 480  * @parent: parent resource descriptor
 481  * @start: resource start address
 482  * @n: resource region size
 483  * @name: reserving caller's ID string
 484  */
 485 struct resource * __request_region(struct resource *parent,
 486                                    resource_size_t start, resource_size_t n,
 487                                    const char *name)
 488 {
 489         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 490
 491         if (res) {
 492                 res->name = name;
 493                 res->start = start;
 494                 res->end = start + n - 1;
 495                 res->flags = IORESOURCE_BUSY;
 496
 497                 write_lock(&resource_lock);
 498
 499                 for (;;) {
 500                         struct resource *conflict;
 501
 502                         conflict = __request_resource(parent, res);
 503                         if (!conflict)
 504                                 break;
 505                         if (conflict != parent) {
 506                                 parent = conflict;
 507                                 if (!(conflict->flags & IORESOURCE_BUSY))
 508                                         continue;
 509                         }
 510
 511                         /* Uhhuh, that didn't work out.. */
 512                         kfree(res);
 513                         res = NULL;
 514                         break;
 515                 }
 516                 write_unlock(&resource_lock);
 517         }
 518         return res;
 519 }
 520 EXPORT_SYMBOL(__request_region);
 521
 522 /**
 523  * __check_region - check if a resource region is busy or free
 524  * @parent: parent resource descriptor
 525  * @start: resource start address
 526  * @n: resource region size
 527  *
 528  * Returns 0 if the region is free at the moment it is checked,
 529  * returns %-EBUSY if the region is busy.
 530  *
 531  * NOTE:
 532  * This function is deprecated because its use is racy.
 533  * Even if it returns 0, a subsequent call to request_region()
 534  * may fail because another driver etc. just allocated the region.
 535  * Do NOT use it.  It will be removed from the kernel.
 536  */
 537 int __check_region(struct resource *parent, resource_size_t start,
 538                         resource_size_t n)
 539 {
 540         struct resource * res;
 541
 542         res = __request_region(parent, start, n, "check-region");
 543         if (!res)
 544                 return -EBUSY;
 545
 546         release_resource(res);
 547         kfree(res);
 548         return 0;
 549 }
 550 EXPORT_SYMBOL(__check_region);
 551
 552 /**
 553  * __release_region - release a previously reserved resource region
 554  * @parent: parent resource descriptor
 555  * @start: resource start address
 556  * @n: resource region size
 557  *
 558  * The described resource region must match a currently busy region.
 559  */
 560 void __release_region(struct resource *parent, resource_size_t start,
 561                         resource_size_t n)
 562 {
 563         struct resource **p;
 564         resource_size_t end;
 565
 566         p = &parent->child;
 567         end = start + n - 1;
 568
 569         write_lock(&resource_lock);
 570
 571         for (;;) {
 572                 struct resource *res = *p;
 573
 574                 if (!res)
 575                         break;
 576                 if (res->start <= start && res->end >= end) {
 577                         if (!(res->flags & IORESOURCE_BUSY)) {
 578                                 p = &res->child;
 579                                 continue;
 580                         }
 581                         if (res->start != start || res->end != end)
 582                                 break;
 583                         *p = res->sibling;
 584                         write_unlock(&resource_lock);
 585                         kfree(res);
 586                         return;
 587                 }
 588                 p = &res->sibling;
 589         }
 590
 591         write_unlock(&resource_lock);
 592
 593         printk(KERN_WARNING "Trying to free nonexistent resource "
 594                 "<%016llx-%016llx>\n", (unsigned long long)start,
 595                 (unsigned long long)end);
 596 }
 597 EXPORT_SYMBOL(__release_region);
 598
 599 /*
 600  * Managed region resource
 601  */
 602 struct region_devres {
 603         struct resource *parent;
 604         resource_size_t start;
 605         resource_size_t n;
 606 };
 607
 608 static void devm_region_release(struct device *dev, void *res)
 609 {
 610         struct region_devres *this = res;
 611
 612         __release_region(this->parent, this->start, this->n);
 613 }
 614
 615 static int devm_region_match(struct device *dev, void *res, void *match_data)
 616 {
 617         struct region_devres *this = res, *match = match_data;
 618
 619         return this->parent == match->parent &&
 620                 this->start == match->start && this->n == match->n;
 621 }
 622
 623 struct resource * __devm_request_region(struct device *dev,
 624                                 struct resource *parent, resource_size_t start,
 625                                 resource_size_t n, const char *name)
 626 {
 627         struct region_devres *dr = NULL;
 628         struct resource *res;
 629
 630         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 631                           GFP_KERNEL);
 632         if (!dr)
 633                 return NULL;
 634
 635         dr->parent = parent;
 636         dr->start = start;
 637         dr->n = n;
 638
 639         res = __request_region(parent, start, n, name);
 640         if (res)
 641                 devres_add(dev, dr);
 642         else
 643                 devres_free(dr);
 644
 645         return res;
 646 }
 647 EXPORT_SYMBOL(__devm_request_region);
 648
 649 void __devm_release_region(struct device *dev, struct resource *parent,
 650                            resource_size_t start, resource_size_t n)
 651 {
 652         struct region_devres match_data = { parent, start, n };
 653
 654         __release_region(parent, start, n);
 655         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
 656                                &match_data));
 657 }
 658 EXPORT_SYMBOL(__devm_release_region);
 659
 660 /*
 661  * Called from init/main.c to reserve IO ports.
 662  */
 663 #define MAXRESERVE 4
 664 static int __init reserve_setup(char *str)
 665 {
 666         static int reserved;
 667         static struct resource reserve[MAXRESERVE];
 668
 669         for (;;) {
 670                 int io_start, io_num;
 671                 int x = reserved;
 672
 673                 if (get_option (&str, &io_start) != 2)
 674                         break;
 675                 if (get_option (&str, &io_num)   == 0)
 676                         break;
 677                 if (x < MAXRESERVE) {
 678                         struct resource *res = reserve + x;
 679                         res->name = "reserved";
 680                         res->start = io_start;
 681                         res->end = io_start + io_num - 1;
 682                         res->flags = IORESOURCE_BUSY;
 683                         res->child = NULL;
 684                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 685                                 reserved = x+1;
 686                 }
 687         }
 688         return 1;
 689 }
 690
 691 __setup("reserve=", reserve_setup);