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 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 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 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 int request_resource(struct resource *root, struct resource *new)
 197 {
 198         struct resource *conflict;
 199
 200         write_lock(&resource_lock);
 201         conflict = __request_resource(root, new);
 202         write_unlock(&resource_lock);
 203         return conflict ? -EBUSY : 0;
 204 }
 205
 206 EXPORT_SYMBOL(request_resource);
 207
 208 struct resource *____request_resource(struct resource *root, struct resource *new)
 209 {
 210         struct resource *conflict;
 211
 212         write_lock(&resource_lock);
 213         conflict = __request_resource(root, new);
 214         write_unlock(&resource_lock);
 215         return conflict;
 216 }
 217
 218 EXPORT_SYMBOL(____request_resource);
 219
 220 int release_resource(struct resource *old)
 221 {
 222         int retval;
 223
 224         write_lock(&resource_lock);
 225         retval = __release_resource(old);
 226         write_unlock(&resource_lock);
 227         return retval;
 228 }
 229
 230 EXPORT_SYMBOL(release_resource);
 231
 232 #ifdef CONFIG_MEMORY_HOTPLUG
 233 /*
 234  * Finds the lowest memory reosurce exists within [res->start.res->end)
 235  * the caller must specify res->start, res->end, res->flags.
 236  * If found, returns 0, res is overwritten, if not found, returns -1.
 237  */
 238 int find_next_system_ram(struct resource *res)
 239 {
 240         resource_size_t start, end;
 241         struct resource *p;
 242
 243         BUG_ON(!res);
 244
 245         start = res->start;
 246         end = res->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->start >= start)
 258                         break;
 259         }
 260         read_unlock(&resource_lock);
 261         if (!p)
 262                 return -1;
 263         /* copy data */
 264         res->start = p->start;
 265         res->end = p->end;
 266         return 0;
 267 }
 268 #endif
 269
 270 /*
 271  * Find empty slot in the resource tree given range and alignment.
 272  */
 273 static int find_resource(struct resource *root, struct resource *new,
 274                          resource_size_t size, resource_size_t min,
 275                          resource_size_t max, resource_size_t align,
 276                          void (*alignf)(void *, struct resource *,
 277                                         resource_size_t, resource_size_t),
 278                          void *alignf_data)
 279 {
 280         struct resource *this = root->child;
 281
 282         new->start = root->start;
 283         /*
 284          * Skip past an allocated resource that starts at 0, since the assignment
 285          * of this->start - 1 to new->end below would cause an underflow.
 286          */
 287         if (this && this->start == 0) {
 288                 new->start = this->end + 1;
 289                 this = this->sibling;
 290         }
 291         for(;;) {
 292                 if (this)
 293                         new->end = this->start - 1;
 294                 else
 295                         new->end = root->end;
 296                 if (new->start < min)
 297                         new->start = min;
 298                 if (new->end > max)
 299                         new->end = max;
 300                 new->start = ALIGN(new->start, align);
 301                 if (alignf)
 302                         alignf(alignf_data, new, size, align);
 303                 if (new->start < new->end && new->end - new->start >= size - 1) {
 304                         new->end = new->start + size - 1;
 305                         return 0;
 306                 }
 307                 if (!this)
 308                         break;
 309                 new->start = this->end + 1;
 310                 this = this->sibling;
 311         }
 312         return -EBUSY;
 313 }
 314
 315 /*
 316  * Allocate empty slot in the resource tree given range and alignment.
 317  */
 318 int allocate_resource(struct resource *root, struct resource *new,
 319                       resource_size_t size, resource_size_t min,
 320                       resource_size_t max, resource_size_t align,
 321                       void (*alignf)(void *, struct resource *,
 322                                      resource_size_t, resource_size_t),
 323                       void *alignf_data)
 324 {
 325         int err;
 326
 327         write_lock(&resource_lock);
 328         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 329         if (err >= 0 && __request_resource(root, new))
 330                 err = -EBUSY;
 331         write_unlock(&resource_lock);
 332         return err;
 333 }
 334
 335 EXPORT_SYMBOL(allocate_resource);
 336
 337 /**
 338  * insert_resource - Inserts a resource in the resource tree
 339  * @parent: parent of the new resource
 340  * @new: new resource to insert
 341  *
 342  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 343  *
 344  * This function is equivalent of request_resource when no conflict
 345  * happens. If a conflict happens, and the conflicting resources
 346  * entirely fit within the range of the new resource, then the new
 347  * resource is inserted and the conflicting resources become childs of
 348  * the new resource.  Otherwise the new resource becomes the child of
 349  * the conflicting resource
 350  */
 351 int insert_resource(struct resource *parent, struct resource *new)
 352 {
 353         int result;
 354         struct resource *first, *next;
 355
 356         write_lock(&resource_lock);
 357  begin:
 358         result = 0;
 359         first = __request_resource(parent, new);
 360         if (!first)
 361                 goto out;
 362
 363         result = -EBUSY;
 364         if (first == parent)
 365                 goto out;
 366
 367         /* Resource fully contained by the clashing resource? Recurse into it */
 368         if (first->start <= new->start && first->end >= new->end) {
 369                 parent = first;
 370                 goto begin;
 371         }
 372
 373         for (next = first; ; next = next->sibling) {
 374                 /* Partial overlap? Bad, and unfixable */
 375                 if (next->start < new->start || next->end > new->end)
 376                         goto out;
 377                 if (!next->sibling)
 378                         break;
 379                 if (next->sibling->start > new->end)
 380                         break;
 381         }
 382
 383         result = 0;
 384
 385         new->parent = parent;
 386         new->sibling = next->sibling;
 387         new->child = first;
 388
 389         next->sibling = NULL;
 390         for (next = first; next; next = next->sibling)
 391                 next->parent = new;
 392
 393         if (parent->child == first) {
 394                 parent->child = new;
 395         } else {
 396                 next = parent->child;
 397                 while (next->sibling != first)
 398                         next = next->sibling;
 399                 next->sibling = new;
 400         }
 401
 402  out:
 403         write_unlock(&resource_lock);
 404         return result;
 405 }
 406
 407 EXPORT_SYMBOL(insert_resource);
 408
 409 /*
 410  * Given an existing resource, change its start and size to match the
 411  * arguments.  Returns -EBUSY if it can't fit.  Existing children of
 412  * the resource are assumed to be immutable.
 413  */
 414 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 415 {
 416         struct resource *tmp, *parent = res->parent;
 417         resource_size_t end = start + size - 1;
 418         int result = -EBUSY;
 419
 420         write_lock(&resource_lock);
 421
 422         if ((start < parent->start) || (end > parent->end))
 423                 goto out;
 424
 425         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 426                 if ((tmp->start < start) || (tmp->end > end))
 427                         goto out;
 428         }
 429
 430         if (res->sibling && (res->sibling->start <= end))
 431                 goto out;
 432
 433         tmp = parent->child;
 434         if (tmp != res) {
 435                 while (tmp->sibling != res)
 436                         tmp = tmp->sibling;
 437                 if (start <= tmp->end)
 438                         goto out;
 439         }
 440
 441         res->start = start;
 442         res->end = end;
 443         result = 0;
 444
 445  out:
 446         write_unlock(&resource_lock);
 447         return result;
 448 }
 449
 450 EXPORT_SYMBOL(adjust_resource);
 451
 452 /*
 453  * This is compatibility stuff for IO resources.
 454  *
 455  * Note how this, unlike the above, knows about
 456  * the IO flag meanings (busy etc).
 457  *
 458  * Request-region creates a new busy region.
 459  *
 460  * Check-region returns non-zero if the area is already busy
 461  *
 462  * Release-region releases a matching busy region.
 463  */
 464 struct resource * __request_region(struct resource *parent,
 465                                    resource_size_t start, resource_size_t n,
 466                                    const char *name)
 467 {
 468         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 469
 470         if (res) {
 471                 res->name = name;
 472                 res->start = start;
 473                 res->end = start + n - 1;
 474                 res->flags = IORESOURCE_BUSY;
 475
 476                 write_lock(&resource_lock);
 477
 478                 for (;;) {
 479                         struct resource *conflict;
 480
 481                         conflict = __request_resource(parent, res);
 482                         if (!conflict)
 483                                 break;
 484                         if (conflict != parent) {
 485                                 parent = conflict;
 486                                 if (!(conflict->flags & IORESOURCE_BUSY))
 487                                         continue;
 488                         }
 489
 490                         /* Uhhuh, that didn't work out.. */
 491                         kfree(res);
 492                         res = NULL;
 493                         break;
 494                 }
 495                 write_unlock(&resource_lock);
 496         }
 497         return res;
 498 }
 499
 500 EXPORT_SYMBOL(__request_region);
 501
 502 int __check_region(struct resource *parent, resource_size_t start,
 503                         resource_size_t n)
 504 {
 505         struct resource * res;
 506
 507         res = __request_region(parent, start, n, "check-region");
 508         if (!res)
 509                 return -EBUSY;
 510
 511         release_resource(res);
 512         kfree(res);
 513         return 0;
 514 }
 515
 516 EXPORT_SYMBOL(__check_region);
 517
 518 void __release_region(struct resource *parent, resource_size_t start,
 519                         resource_size_t n)
 520 {
 521         struct resource **p;
 522         resource_size_t end;
 523
 524         p = &parent->child;
 525         end = start + n - 1;
 526
 527         write_lock(&resource_lock);
 528
 529         for (;;) {
 530                 struct resource *res = *p;
 531
 532                 if (!res)
 533                         break;
 534                 if (res->start <= start && res->end >= end) {
 535                         if (!(res->flags & IORESOURCE_BUSY)) {
 536                                 p = &res->child;
 537                                 continue;
 538                         }
 539                         if (res->start != start || res->end != end)
 540                                 break;
 541                         *p = res->sibling;
 542                         write_unlock(&resource_lock);
 543                         kfree(res);
 544                         return;
 545                 }
 546                 p = &res->sibling;
 547         }
 548
 549         write_unlock(&resource_lock);
 550
 551         printk(KERN_WARNING "Trying to free nonexistent resource "
 552                 "<%016llx-%016llx>\n", (unsigned long long)start,
 553                 (unsigned long long)end);
 554 }
 555
 556 EXPORT_SYMBOL(__release_region);
 557
 558 /*
 559  * Called from init/main.c to reserve IO ports.
 560  */
 561 #define MAXRESERVE 4
 562 static int __init reserve_setup(char *str)
 563 {
 564         static int reserved;
 565         static struct resource reserve[MAXRESERVE];
 566
 567         for (;;) {
 568                 int io_start, io_num;
 569                 int x = reserved;
 570
 571                 if (get_option (&str, &io_start) != 2)
 572                         break;
 573                 if (get_option (&str, &io_num)   == 0)
 574                         break;
 575                 if (x < MAXRESERVE) {
 576                         struct resource *res = reserve + x;
 577                         res->name = "reserved";
 578                         res->start = io_start;
 579                         res->end = io_start + io_num - 1;
 580                         res->flags = IORESOURCE_BUSY;
 581                         res->child = NULL;
 582                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 583                                 reserved = x+1;
 584                 }
 585         }
 586         return 1;
 587 }
 588
 589 __setup("reserve=", reserve_setup);