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