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/config.h>
  11 #include <linux/module.h>
  12 #include <linux/sched.h>
  13 #include <linux/errno.h>
  14 #include <linux/ioport.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/fs.h>
  19 #include <linux/proc_fs.h>
  20 #include <linux/seq_file.h>
  21 #include <asm/io.h>
  22
  23
  24 struct resource ioport_resource = {
  25         .name   = "PCI IO",
  26         .start  = 0x0000,
  27         .end    = IO_SPACE_LIMIT,
  28         .flags  = IORESOURCE_IO,
  29 };
  30
  31 EXPORT_SYMBOL(ioport_resource);
  32
  33 struct resource iomem_resource = {
  34         .name   = "PCI mem",
  35         .start  = 0UL,
  36         .end    = ~0UL,
  37         .flags  = IORESOURCE_MEM,
  38 };
  39
  40 EXPORT_SYMBOL(iomem_resource);
  41
  42 static rwlock_t resource_lock = RW_LOCK_UNLOCKED;
  43
  44 #ifdef CONFIG_PROC_FS
  45
  46 enum { MAX_IORES_LEVEL = 5 };
  47
  48 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  49 {
  50         struct resource *p = v;
  51         (*pos)++;
  52         if (p->child)
  53                 return p->child;
  54         while (!p->sibling && p->parent)
  55                 p = p->parent;
  56         return p->sibling;
  57 }
  58
  59 static void *r_start(struct seq_file *m, loff_t *pos)
  60 {
  61         struct resource *p = m->private;
  62         loff_t l = 0;
  63         read_lock(&resource_lock);
  64         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  65                 ;
  66         return p;
  67 }
  68
  69 static void r_stop(struct seq_file *m, void *v)
  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*lx-%0*lx : %s\n",
  85                         depth * 2, "",
  86                         width, r->start,
  87                         width, r->end,
  88                         r->name ? r->name : "<BAD>");
  89         return 0;
  90 }
  91
  92 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 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 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         unsigned long start = new->start;
 153         unsigned long 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 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 struct resource *____request_resource(struct resource *root, struct resource *new)
 210 {
 211         struct resource *conflict;
 212
 213         write_lock(&resource_lock);
 214         conflict = __request_resource(root, new);
 215         write_unlock(&resource_lock);
 216         return conflict;
 217 }
 218
 219 EXPORT_SYMBOL(____request_resource);
 220
 221 int release_resource(struct resource *old)
 222 {
 223         int retval;
 224
 225         write_lock(&resource_lock);
 226         retval = __release_resource(old);
 227         write_unlock(&resource_lock);
 228         return retval;
 229 }
 230
 231 EXPORT_SYMBOL(release_resource);
 232
 233 /*
 234  * Find empty slot in the resource tree given range and alignment.
 235  */
 236 static int find_resource(struct resource *root, struct resource *new,
 237                          unsigned long size,
 238                          unsigned long min, unsigned long max,
 239                          unsigned long align,
 240                          void (*alignf)(void *, struct resource *,
 241                                         unsigned long, unsigned long),
 242                          void *alignf_data)
 243 {
 244         struct resource *this = root->child;
 245
 246         new->start = root->start;
 247         /*
 248          * Skip past an allocated resource that starts at 0, since the assignment
 249          * of this->start - 1 to new->end below would cause an underflow.
 250          */
 251         if (this && this->start == 0) {
 252                 new->start = this->end + 1;
 253                 this = this->sibling;
 254         }
 255         for(;;) {
 256                 if (this)
 257                         new->end = this->start - 1;
 258                 else
 259                         new->end = root->end;
 260                 if (new->start < min)
 261                         new->start = min;
 262                 if (new->end > max)
 263                         new->end = max;
 264                 new->start = (new->start + align - 1) & ~(align - 1);
 265                 if (alignf)
 266                         alignf(alignf_data, new, size, align);
 267                 if (new->start < new->end && new->end - new->start + 1 >= size) {
 268                         new->end = new->start + size - 1;
 269                         return 0;
 270                 }
 271                 if (!this)
 272                         break;
 273                 new->start = this->end + 1;
 274                 this = this->sibling;
 275         }
 276         return -EBUSY;
 277 }
 278
 279 /*
 280  * Allocate empty slot in the resource tree given range and alignment.
 281  */
 282 int allocate_resource(struct resource *root, struct resource *new,
 283                       unsigned long size,
 284                       unsigned long min, unsigned long max,
 285                       unsigned long align,
 286                       void (*alignf)(void *, struct resource *,
 287                                      unsigned long, unsigned long),
 288                       void *alignf_data)
 289 {
 290         int err;
 291
 292         write_lock(&resource_lock);
 293         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 294         if (err >= 0 && __request_resource(root, new))
 295                 err = -EBUSY;
 296         write_unlock(&resource_lock);
 297         return err;
 298 }
 299
 300 EXPORT_SYMBOL(allocate_resource);
 301
 302 /**
 303  * insert_resource - Inserts a resource in the resource tree
 304  * @parent: parent of the new resource
 305  * @new: new resource to insert
 306  *
 307  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 308  *
 309  * This function is equivalent of request_resource when no conflict
 310  * happens. If a conflict happens, and the conflicting resources
 311  * entirely fit within the range of the new resource, then the new
 312  * resource is inserted and the conflicting resources become childs of
 313  * the new resource.  Otherwise the new resource becomes the child of
 314  * the conflicting resource
 315  */
 316 int insert_resource(struct resource *parent, struct resource *new)
 317 {
 318         int result;
 319         struct resource *first, *next;
 320
 321         write_lock(&resource_lock);
 322  begin:
 323         result = 0;
 324         first = __request_resource(parent, new);
 325         if (!first)
 326                 goto out;
 327
 328         result = -EBUSY;
 329         if (first == parent)
 330                 goto out;
 331
 332         /* Resource fully contained by the clashing resource? Recurse into it */
 333         if (first->start <= new->start && first->end >= new->end) {
 334                 parent = first;
 335                 goto begin;
 336         }
 337
 338         for (next = first; ; next = next->sibling) {
 339                 /* Partial overlap? Bad, and unfixable */
 340                 if (next->start < new->start || next->end > new->end)
 341                         goto out;
 342                 if (!next->sibling)
 343                         break;
 344                 if (next->sibling->start > new->end)
 345                         break;
 346         }
 347
 348         result = 0;
 349
 350         new->parent = parent;
 351         new->sibling = next->sibling;
 352         new->child = first;
 353
 354         next->sibling = NULL;
 355         for (next = first; next; next = next->sibling)
 356                 next->parent = new;
 357
 358         if (parent->child == first) {
 359                 parent->child = new;
 360         } else {
 361                 next = parent->child;
 362                 while (next->sibling != first)
 363                         next = next->sibling;
 364                 next->sibling = new;
 365         }
 366
 367  out:
 368         write_unlock(&resource_lock);
 369         return result;
 370 }
 371
 372 EXPORT_SYMBOL(insert_resource);
 373
 374 /*
 375  * Given an existing resource, change its start and size to match the
 376  * arguments.  Returns -EBUSY if it can't fit.  Existing children of
 377  * the resource are assumed to be immutable.
 378  */
 379 int adjust_resource(struct resource *res, unsigned long start, unsigned long size)
 380 {
 381         struct resource *tmp, *parent = res->parent;
 382         unsigned long end = start + size - 1;
 383         int result = -EBUSY;
 384
 385         write_lock(&resource_lock);
 386
 387         if ((start < parent->start) || (end > parent->end))
 388                 goto out;
 389
 390         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 391                 if ((tmp->start < start) || (tmp->end > end))
 392                         goto out;
 393         }
 394
 395         if (res->sibling && (res->sibling->start <= end))
 396                 goto out;
 397
 398         tmp = parent->child;
 399         if (tmp != res) {
 400                 while (tmp->sibling != res)
 401                         tmp = tmp->sibling;
 402                 if (start <= tmp->end)
 403                         goto out;
 404         }
 405
 406         res->start = start;
 407         res->end = end;
 408         result = 0;
 409
 410  out:
 411         write_unlock(&resource_lock);
 412         return result;
 413 }
 414
 415 EXPORT_SYMBOL(adjust_resource);
 416
 417 /*
 418  * This is compatibility stuff for IO resources.
 419  *
 420  * Note how this, unlike the above, knows about
 421  * the IO flag meanings (busy etc).
 422  *
 423  * Request-region creates a new busy region.
 424  *
 425  * Check-region returns non-zero if the area is already busy
 426  *
 427  * Release-region releases a matching busy region.
 428  */
 429 struct resource * __request_region(struct resource *parent, unsigned long start, unsigned long n, const char *name)
 430 {
 431         struct resource *res = kmalloc(sizeof(*res), GFP_KERNEL);
 432
 433         if (res) {
 434                 memset(res, 0, sizeof(*res));
 435                 res->name = name;
 436                 res->start = start;
 437                 res->end = start + n - 1;
 438                 res->flags = IORESOURCE_BUSY;
 439
 440                 write_lock(&resource_lock);
 441
 442                 for (;;) {
 443                         struct resource *conflict;
 444
 445                         conflict = __request_resource(parent, res);
 446                         if (!conflict)
 447                                 break;
 448                         if (conflict != parent) {
 449                                 parent = conflict;
 450                                 if (!(conflict->flags & IORESOURCE_BUSY))
 451                                         continue;
 452                         }
 453
 454                         /* Uhhuh, that didn't work out.. */
 455                         kfree(res);
 456                         res = NULL;
 457                         break;
 458                 }
 459                 write_unlock(&resource_lock);
 460         }
 461         return res;
 462 }
 463
 464 EXPORT_SYMBOL(__request_region);
 465
 466 int __deprecated __check_region(struct resource *parent, unsigned long start, unsigned long n)
 467 {
 468         struct resource * res;
 469
 470         res = __request_region(parent, start, n, "check-region");
 471         if (!res)
 472                 return -EBUSY;
 473
 474         release_resource(res);
 475         kfree(res);
 476         return 0;
 477 }
 478
 479 EXPORT_SYMBOL(__check_region);
 480
 481 void __release_region(struct resource *parent, unsigned long start, unsigned long n)
 482 {
 483         struct resource **p;
 484         unsigned long end;
 485
 486         p = &parent->child;
 487         end = start + n - 1;
 488
 489         write_lock(&resource_lock);
 490
 491         for (;;) {
 492                 struct resource *res = *p;
 493
 494                 if (!res)
 495                         break;
 496                 if (res->start <= start && res->end >= end) {
 497                         if (!(res->flags & IORESOURCE_BUSY)) {
 498                                 p = &res->child;
 499                                 continue;
 500                         }
 501                         if (res->start != start || res->end != end)
 502                                 break;
 503                         *p = res->sibling;
 504                         write_unlock(&resource_lock);
 505                         kfree(res);
 506                         return;
 507                 }
 508                 p = &res->sibling;
 509         }
 510
 511         write_unlock(&resource_lock);
 512
 513         printk(KERN_WARNING "Trying to free nonexistent resource <%08lx-%08lx>\n", start, end);
 514 }
 515
 516 EXPORT_SYMBOL(__release_region);
 517
 518 /*
 519  * Called from init/main.c to reserve IO ports.
 520  */
 521 #define MAXRESERVE 4
 522 static int __init reserve_setup(char *str)
 523 {
 524         static int reserved;
 525         static struct resource reserve[MAXRESERVE];
 526
 527         for (;;) {
 528                 int io_start, io_num;
 529                 int x = reserved;
 530
 531                 if (get_option (&str, &io_start) != 2)
 532                         break;
 533                 if (get_option (&str, &io_num)   == 0)
 534                         break;
 535                 if (x < MAXRESERVE) {
 536                         struct resource *res = reserve + x;
 537                         res->name = "reserved";
 538                         res->start = io_start;
 539                         res->end = io_start + io_num - 1;
 540                         res->flags = IORESOURCE_BUSY;
 541                         res->child = NULL;
 542                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 543                                 reserved = x+1;
 544                 }
 545         }
 546         return 1;
 547 }
 548
 549 __setup("reserve=", reserve_setup);