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