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 DEFINE_RWLOCK(resource_lock);
  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         __acquires(resource_lock)
  61 {
  62         struct resource *p = m->private;
  63         loff_t l = 0;
  64         read_lock(&resource_lock);
  65         for (p = p->child; p && l < *pos; p = r_next(m, p, &l))
  66                 ;
  67         return p;
  68 }
  69
  70 static void r_stop(struct seq_file *m, void *v)
  71         __releases(resource_lock)
  72 {
  73         read_unlock(&resource_lock);
  74 }
  75
  76 static int r_show(struct seq_file *m, void *v)
  77 {
  78         struct resource *root = m->private;
  79         struct resource *r = v, *p;
  80         int width = root->end < 0x10000 ? 4 : 8;
  81         int depth;
  82
  83         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
  84                 if (p->parent == root)
  85                         break;
  86         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
  87                         depth * 2, "",
  88                         width, (unsigned long long) r->start,
  89                         width, (unsigned long long) r->end,
  90                         r->name ? r->name : "<BAD>");
  91         return 0;
  92 }
  93
  94 static struct seq_operations resource_op = {
  95         .start  = r_start,
  96         .next   = r_next,
  97         .stop   = r_stop,
  98         .show   = r_show,
  99 };
 100
 101 static int ioports_open(struct inode *inode, struct file *file)
 102 {
 103         int res = seq_open(file, &resource_op);
 104         if (!res) {
 105                 struct seq_file *m = file->private_data;
 106                 m->private = &ioport_resource;
 107         }
 108         return res;
 109 }
 110
 111 static int iomem_open(struct inode *inode, struct file *file)
 112 {
 113         int res = seq_open(file, &resource_op);
 114         if (!res) {
 115                 struct seq_file *m = file->private_data;
 116                 m->private = &iomem_resource;
 117         }
 118         return res;
 119 }
 120
 121 static struct file_operations proc_ioports_operations = {
 122         .open           = ioports_open,
 123         .read           = seq_read,
 124         .llseek         = seq_lseek,
 125         .release        = seq_release,
 126 };
 127
 128 static struct file_operations proc_iomem_operations = {
 129         .open           = iomem_open,
 130         .read           = seq_read,
 131         .llseek         = seq_lseek,
 132         .release        = seq_release,
 133 };
 134
 135 static int __init ioresources_init(void)
 136 {
 137         struct proc_dir_entry *entry;
 138
 139         entry = create_proc_entry("ioports", 0, NULL);
 140         if (entry)
 141                 entry->proc_fops = &proc_ioports_operations;
 142         entry = create_proc_entry("iomem", 0, NULL);
 143         if (entry)
 144                 entry->proc_fops = &proc_iomem_operations;
 145         return 0;
 146 }
 147 __initcall(ioresources_init);
 148
 149 #endif /* CONFIG_PROC_FS */
 150
 151 /* Return the conflict entry if you can't request it */
 152 static struct resource * __request_resource(struct resource *root, struct resource *new)
 153 {
 154         resource_size_t start = new->start;
 155         resource_size_t end = new->end;
 156         struct resource *tmp, **p;
 157
 158         if (end < start)
 159                 return root;
 160         if (start < root->start)
 161                 return root;
 162         if (end > root->end)
 163                 return root;
 164         p = &root->child;
 165         for (;;) {
 166                 tmp = *p;
 167                 if (!tmp || tmp->start > end) {
 168                         new->sibling = tmp;
 169                         *p = new;
 170                         new->parent = root;
 171                         return NULL;
 172                 }
 173                 p = &tmp->sibling;
 174                 if (tmp->end < start)
 175                         continue;
 176                 return tmp;
 177         }
 178 }
 179
 180 static int __release_resource(struct resource *old)
 181 {
 182         struct resource *tmp, **p;
 183
 184         p = &old->parent->child;
 185         for (;;) {
 186                 tmp = *p;
 187                 if (!tmp)
 188                         break;
 189                 if (tmp == old) {
 190                         *p = tmp->sibling;
 191                         old->parent = NULL;
 192                         return 0;
 193                 }
 194                 p = &tmp->sibling;
 195         }
 196         return -EINVAL;
 197 }
 198
 199 int request_resource(struct resource *root, struct resource *new)
 200 {
 201         struct resource *conflict;
 202
 203         write_lock(&resource_lock);
 204         conflict = __request_resource(root, new);
 205         write_unlock(&resource_lock);
 206         return conflict ? -EBUSY : 0;
 207 }
 208
 209 EXPORT_SYMBOL(request_resource);
 210
 211 struct resource *____request_resource(struct resource *root, struct resource *new)
 212 {
 213         struct resource *conflict;
 214
 215         write_lock(&resource_lock);
 216         conflict = __request_resource(root, new);
 217         write_unlock(&resource_lock);
 218         return conflict;
 219 }
 220
 221 EXPORT_SYMBOL(____request_resource);
 222
 223 int release_resource(struct resource *old)
 224 {
 225         int retval;
 226
 227         write_lock(&resource_lock);
 228         retval = __release_resource(old);
 229         write_unlock(&resource_lock);
 230         return retval;
 231 }
 232
 233 EXPORT_SYMBOL(release_resource);
 234
 235 /*
 236  * Find empty slot in the resource tree given range and alignment.
 237  */
 238 static int find_resource(struct resource *root, struct resource *new,
 239                          resource_size_t size, resource_size_t min,
 240                          resource_size_t max, resource_size_t align,
 241                          void (*alignf)(void *, struct resource *,
 242                                         resource_size_t, resource_size_t),
 243                          void *alignf_data)
 244 {
 245         struct resource *this = root->child;
 246
 247         new->start = root->start;
 248         /*
 249          * Skip past an allocated resource that starts at 0, since the assignment
 250          * of this->start - 1 to new->end below would cause an underflow.
 251          */
 252         if (this && this->start == 0) {
 253                 new->start = this->end + 1;
 254                 this = this->sibling;
 255         }
 256         for(;;) {
 257                 if (this)
 258                         new->end = this->start - 1;
 259                 else
 260                         new->end = root->end;
 261                 if (new->start < min)
 262                         new->start = min;
 263                 if (new->end > max)
 264                         new->end = max;
 265                 new->start = ALIGN(new->start, align);
 266                 if (alignf)
 267                         alignf(alignf_data, new, size, align);
 268                 if (new->start < new->end && new->end - new->start >= size - 1) {
 269                         new->end = new->start + size - 1;
 270                         return 0;
 271                 }
 272                 if (!this)
 273                         break;
 274                 new->start = this->end + 1;
 275                 this = this->sibling;
 276         }
 277         return -EBUSY;
 278 }
 279
 280 /*
 281  * Allocate empty slot in the resource tree given range and alignment.
 282  */
 283 int allocate_resource(struct resource *root, struct resource *new,
 284                       resource_size_t size, resource_size_t min,
 285                       resource_size_t max, resource_size_t align,
 286                       void (*alignf)(void *, struct resource *,
 287                                      resource_size_t, resource_size_t),
 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, resource_size_t start, resource_size_t size)
 380 {
 381         struct resource *tmp, *parent = res->parent;
 382         resource_size_t 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,
 430                                    resource_size_t start, resource_size_t n,
 431                                    const char *name)
 432 {
 433         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 434
 435         if (res) {
 436                 res->name = name;
 437                 res->start = start;
 438                 res->end = start + n - 1;
 439                 res->flags = IORESOURCE_BUSY;
 440
 441                 write_lock(&resource_lock);
 442
 443                 for (;;) {
 444                         struct resource *conflict;
 445
 446                         conflict = __request_resource(parent, res);
 447                         if (!conflict)
 448                                 break;
 449                         if (conflict != parent) {
 450                                 parent = conflict;
 451                                 if (!(conflict->flags & IORESOURCE_BUSY))
 452                                         continue;
 453                         }
 454
 455                         /* Uhhuh, that didn't work out.. */
 456                         kfree(res);
 457                         res = NULL;
 458                         break;
 459                 }
 460                 write_unlock(&resource_lock);
 461         }
 462         return res;
 463 }
 464
 465 EXPORT_SYMBOL(__request_region);
 466
 467 int __check_region(struct resource *parent, resource_size_t start,
 468                         resource_size_t n)
 469 {
 470         struct resource * res;
 471
 472         res = __request_region(parent, start, n, "check-region");
 473         if (!res)
 474                 return -EBUSY;
 475
 476         release_resource(res);
 477         kfree(res);
 478         return 0;
 479 }
 480
 481 EXPORT_SYMBOL(__check_region);
 482
 483 void __release_region(struct resource *parent, resource_size_t start,
 484                         resource_size_t n)
 485 {
 486         struct resource **p;
 487         resource_size_t end;
 488
 489         p = &parent->child;
 490         end = start + n - 1;
 491
 492         write_lock(&resource_lock);
 493
 494         for (;;) {
 495                 struct resource *res = *p;
 496
 497                 if (!res)
 498                         break;
 499                 if (res->start <= start && res->end >= end) {
 500                         if (!(res->flags & IORESOURCE_BUSY)) {
 501                                 p = &res->child;
 502                                 continue;
 503                         }
 504                         if (res->start != start || res->end != end)
 505                                 break;
 506                         *p = res->sibling;
 507                         write_unlock(&resource_lock);
 508                         kfree(res);
 509                         return;
 510                 }
 511                 p = &res->sibling;
 512         }
 513
 514         write_unlock(&resource_lock);
 515
 516         printk(KERN_WARNING "Trying to free nonexistent resource "
 517                 "<%016llx-%016llx>\n", (unsigned long long)start,
 518                 (unsigned long long)end);
 519 }
 520
 521 EXPORT_SYMBOL(__release_region);
 522
 523 /*
 524  * Called from init/main.c to reserve IO ports.
 525  */
 526 #define MAXRESERVE 4
 527 static int __init reserve_setup(char *str)
 528 {
 529         static int reserved;
 530         static struct resource reserve[MAXRESERVE];
 531
 532         for (;;) {
 533                 int io_start, io_num;
 534                 int x = reserved;
 535
 536                 if (get_option (&str, &io_start) != 2)
 537                         break;
 538                 if (get_option (&str, &io_num)   == 0)
 539                         break;
 540                 if (x < MAXRESERVE) {
 541                         struct resource *res = reserve + x;
 542                         res->name = "reserved";
 543                         res->start = io_start;
 544                         res->end = io_start + io_num - 1;
 545                         res->flags = IORESOURCE_BUSY;
 546                         res->child = NULL;
 547                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 548                                 reserved = x+1;
 549                 }
 550         }
 551         return 1;
 552 }
 553
 554 __setup("reserve=", reserve_setup);