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/errno.h>
  12 #include <linux/ioport.h>
  13 #include <linux/init.h>
  14 #include <linux/slab.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/fs.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/sched.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/device.h>
  21 #include <linux/pfn.h>
  22 #include <asm/io.h>
  23
  24
  25 struct resource ioport_resource = {
  26         .name   = "PCI IO",
  27         .start  = 0,
  28         .end    = IO_SPACE_LIMIT,
  29         .flags  = IORESOURCE_IO,
  30 };
  31 EXPORT_SYMBOL(ioport_resource);
  32
  33 struct resource iomem_resource = {
  34         .name   = "PCI mem",
  35         .start  = 0,
  36         .end    = -1,
  37         .flags  = IORESOURCE_MEM,
  38 };
  39 EXPORT_SYMBOL(iomem_resource);
  40
  41 static DEFINE_RWLOCK(resource_lock);
  42
  43 static void *r_next(struct seq_file *m, void *v, loff_t *pos)
  44 {
  45         struct resource *p = v;
  46         (*pos)++;
  47         if (p->child)
  48                 return p->child;
  49         while (!p->sibling && p->parent)
  50                 p = p->parent;
  51         return p->sibling;
  52 }
  53
  54 #ifdef CONFIG_PROC_FS
  55
  56 enum { MAX_IORES_LEVEL = 5 };
  57
  58 static void *r_start(struct seq_file *m, loff_t *pos)
  59         __acquires(resource_lock)
  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         __releases(resource_lock)
  71 {
  72         read_unlock(&resource_lock);
  73 }
  74
  75 static int r_show(struct seq_file *m, void *v)
  76 {
  77         struct resource *root = m->private;
  78         struct resource *r = v, *p;
  79         int width = root->end < 0x10000 ? 4 : 8;
  80         int depth;
  81
  82         for (depth = 0, p = r; depth < MAX_IORES_LEVEL; depth++, p = p->parent)
  83                 if (p->parent == root)
  84                         break;
  85         seq_printf(m, "%*s%0*llx-%0*llx : %s\n",
  86                         depth * 2, "",
  87                         width, (unsigned long long) r->start,
  88                         width, (unsigned long long) r->end,
  89                         r->name ? r->name : "<BAD>");
  90         return 0;
  91 }
  92
  93 static const struct seq_operations resource_op = {
  94         .start  = r_start,
  95         .next   = r_next,
  96         .stop   = r_stop,
  97         .show   = r_show,
  98 };
  99
 100 static int ioports_open(struct inode *inode, struct file *file)
 101 {
 102         int res = seq_open(file, &resource_op);
 103         if (!res) {
 104                 struct seq_file *m = file->private_data;
 105                 m->private = &ioport_resource;
 106         }
 107         return res;
 108 }
 109
 110 static int iomem_open(struct inode *inode, struct file *file)
 111 {
 112         int res = seq_open(file, &resource_op);
 113         if (!res) {
 114                 struct seq_file *m = file->private_data;
 115                 m->private = &iomem_resource;
 116         }
 117         return res;
 118 }
 119
 120 static const struct file_operations proc_ioports_operations = {
 121         .open           = ioports_open,
 122         .read           = seq_read,
 123         .llseek         = seq_lseek,
 124         .release        = seq_release,
 125 };
 126
 127 static const struct file_operations proc_iomem_operations = {
 128         .open           = iomem_open,
 129         .read           = seq_read,
 130         .llseek         = seq_lseek,
 131         .release        = seq_release,
 132 };
 133
 134 static int __init ioresources_init(void)
 135 {
 136         proc_create("ioports", 0, NULL, &proc_ioports_operations);
 137         proc_create("iomem", 0, NULL, &proc_iomem_operations);
 138         return 0;
 139 }
 140 __initcall(ioresources_init);
 141
 142 #endif /* CONFIG_PROC_FS */
 143
 144 /* Return the conflict entry if you can't request it */
 145 static struct resource * __request_resource(struct resource *root, struct resource *new)
 146 {
 147         resource_size_t start = new->start;
 148         resource_size_t end = new->end;
 149         struct resource *tmp, **p;
 150
 151         if (end < start)
 152                 return root;
 153         if (start < root->start)
 154                 return root;
 155         if (end > root->end)
 156                 return root;
 157         p = &root->child;
 158         for (;;) {
 159                 tmp = *p;
 160                 if (!tmp || tmp->start > end) {
 161                         new->sibling = tmp;
 162                         *p = new;
 163                         new->parent = root;
 164                         return NULL;
 165                 }
 166                 p = &tmp->sibling;
 167                 if (tmp->end < start)
 168                         continue;
 169                 return tmp;
 170         }
 171 }
 172
 173 static int __release_resource(struct resource *old)
 174 {
 175         struct resource *tmp, **p;
 176
 177         p = &old->parent->child;
 178         for (;;) {
 179                 tmp = *p;
 180                 if (!tmp)
 181                         break;
 182                 if (tmp == old) {
 183                         *p = tmp->sibling;
 184                         old->parent = NULL;
 185                         return 0;
 186                 }
 187                 p = &tmp->sibling;
 188         }
 189         return -EINVAL;
 190 }
 191
 192 static void __release_child_resources(struct resource *r)
 193 {
 194         struct resource *tmp, *p;
 195         resource_size_t size;
 196
 197         p = r->child;
 198         r->child = NULL;
 199         while (p) {
 200                 tmp = p;
 201                 p = p->sibling;
 202
 203                 tmp->parent = NULL;
 204                 tmp->sibling = NULL;
 205                 __release_child_resources(tmp);
 206
 207                 printk(KERN_DEBUG "release child resource %pR\n", tmp);
 208                 /* need to restore size, and keep flags */
 209                 size = resource_size(tmp);
 210                 tmp->start = 0;
 211                 tmp->end = size - 1;
 212         }
 213 }
 214
 215 void release_child_resources(struct resource *r)
 216 {
 217         write_lock(&resource_lock);
 218         __release_child_resources(r);
 219         write_unlock(&resource_lock);
 220 }
 221
 222 /**
 223  * request_resource_conflict - request and reserve an I/O or memory resource
 224  * @root: root resource descriptor
 225  * @new: resource descriptor desired by caller
 226  *
 227  * Returns 0 for success, conflict resource on error.
 228  */
 229 struct resource *request_resource_conflict(struct resource *root, struct resource *new)
 230 {
 231         struct resource *conflict;
 232
 233         write_lock(&resource_lock);
 234         conflict = __request_resource(root, new);
 235         write_unlock(&resource_lock);
 236         return conflict;
 237 }
 238
 239 /**
 240  * request_resource - request and reserve an I/O or memory resource
 241  * @root: root resource descriptor
 242  * @new: resource descriptor desired by caller
 243  *
 244  * Returns 0 for success, negative error code on error.
 245  */
 246 int request_resource(struct resource *root, struct resource *new)
 247 {
 248         struct resource *conflict;
 249
 250         conflict = request_resource_conflict(root, new);
 251         return conflict ? -EBUSY : 0;
 252 }
 253
 254 EXPORT_SYMBOL(request_resource);
 255
 256 /**
 257  * release_resource - release a previously reserved resource
 258  * @old: resource pointer
 259  */
 260 int release_resource(struct resource *old)
 261 {
 262         int retval;
 263
 264         write_lock(&resource_lock);
 265         retval = __release_resource(old);
 266         write_unlock(&resource_lock);
 267         return retval;
 268 }
 269
 270 EXPORT_SYMBOL(release_resource);
 271
 272 #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
 273 /*
 274  * Finds the lowest memory reosurce exists within [res->start.res->end)
 275  * the caller must specify res->start, res->end, res->flags and "name".
 276  * If found, returns 0, res is overwritten, if not found, returns -1.
 277  */
 278 static int find_next_system_ram(struct resource *res, char *name)
 279 {
 280         resource_size_t start, end;
 281         struct resource *p;
 282
 283         BUG_ON(!res);
 284
 285         start = res->start;
 286         end = res->end;
 287         BUG_ON(start >= end);
 288
 289         read_lock(&resource_lock);
 290         for (p = iomem_resource.child; p ; p = p->sibling) {
 291                 /* system ram is just marked as IORESOURCE_MEM */
 292                 if (p->flags != res->flags)
 293                         continue;
 294                 if (name && strcmp(p->name, name))
 295                         continue;
 296                 if (p->start > end) {
 297                         p = NULL;
 298                         break;
 299                 }
 300                 if ((p->end >= start) && (p->start < end))
 301                         break;
 302         }
 303         read_unlock(&resource_lock);
 304         if (!p)
 305                 return -1;
 306         /* copy data */
 307         if (res->start < p->start)
 308                 res->start = p->start;
 309         if (res->end > p->end)
 310                 res->end = p->end;
 311         return 0;
 312 }
 313
 314 /*
 315  * This function calls callback against all memory range of "System RAM"
 316  * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
 317  * Now, this function is only for "System RAM".
 318  */
 319 int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 320                 void *arg, int (*func)(unsigned long, unsigned long, void *))
 321 {
 322         struct resource res;
 323         unsigned long pfn, end_pfn;
 324         u64 orig_end;
 325         int ret = -1;
 326
 327         res.start = (u64) start_pfn << PAGE_SHIFT;
 328         res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
 329         res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 330         orig_end = res.end;
 331         while ((res.start < res.end) &&
 332                 (find_next_system_ram(&res, "System RAM") >= 0)) {
 333                 pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 334                 end_pfn = (res.end + 1) >> PAGE_SHIFT;
 335                 if (end_pfn > pfn)
 336                         ret = (*func)(pfn, end_pfn - pfn, arg);
 337                 if (ret)
 338                         break;
 339                 res.start = res.end + 1;
 340                 res.end = orig_end;
 341         }
 342         return ret;
 343 }
 344
 345 #endif
 346
 347 static int __is_ram(unsigned long pfn, unsigned long nr_pages, void *arg)
 348 {
 349         return 1;
 350 }
 351 /*
 352  * This generic page_is_ram() returns true if specified address is
 353  * registered as "System RAM" in iomem_resource list.
 354  */
 355 int __weak page_is_ram(unsigned long pfn)
 356 {
 357         return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
 358 }
 359
 360 /*
 361  * Find empty slot in the resource tree given range and alignment.
 362  */
 363 static int find_resource(struct resource *root, struct resource *new,
 364                          resource_size_t size, resource_size_t min,
 365                          resource_size_t max, resource_size_t align,
 366                          resource_size_t (*alignf)(void *,
 367                                                    const struct resource *,
 368                                                    resource_size_t,
 369                                                    resource_size_t),
 370                          void *alignf_data)
 371 {
 372         struct resource *this = root->child;
 373         struct resource tmp = *new;
 374
 375         tmp.start = root->start;
 376         /*
 377          * Skip past an allocated resource that starts at 0, since the assignment
 378          * of this->start - 1 to tmp->end below would cause an underflow.
 379          */
 380         if (this && this->start == 0) {
 381                 tmp.start = this->end + 1;
 382                 this = this->sibling;
 383         }
 384         for(;;) {
 385                 if (this)
 386                         tmp.end = this->start - 1;
 387                 else
 388                         tmp.end = root->end;
 389                 if (tmp.start < min)
 390                         tmp.start = min;
 391                 if (tmp.end > max)
 392                         tmp.end = max;
 393                 tmp.start = ALIGN(tmp.start, align);
 394                 if (alignf)
 395                         tmp.start = alignf(alignf_data, &tmp, size, align);
 396                 if (tmp.start < tmp.end && tmp.end - tmp.start >= size - 1) {
 397                         new->start = tmp.start;
 398                         new->end = tmp.start + size - 1;
 399                         return 0;
 400                 }
 401                 if (!this)
 402                         break;
 403                 tmp.start = this->end + 1;
 404                 this = this->sibling;
 405         }
 406         return -EBUSY;
 407 }
 408
 409 /**
 410  * allocate_resource - allocate empty slot in the resource tree given range & alignment
 411  * @root: root resource descriptor
 412  * @new: resource descriptor desired by caller
 413  * @size: requested resource region size
 414  * @min: minimum size to allocate
 415  * @max: maximum size to allocate
 416  * @align: alignment requested, in bytes
 417  * @alignf: alignment function, optional, called if not NULL
 418  * @alignf_data: arbitrary data to pass to the @alignf function
 419  */
 420 int allocate_resource(struct resource *root, struct resource *new,
 421                       resource_size_t size, resource_size_t min,
 422                       resource_size_t max, resource_size_t align,
 423                       resource_size_t (*alignf)(void *,
 424                                                 const struct resource *,
 425                                                 resource_size_t,
 426                                                 resource_size_t),
 427                       void *alignf_data)
 428 {
 429         int err;
 430
 431         write_lock(&resource_lock);
 432         err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
 433         if (err >= 0 && __request_resource(root, new))
 434                 err = -EBUSY;
 435         write_unlock(&resource_lock);
 436         return err;
 437 }
 438
 439 EXPORT_SYMBOL(allocate_resource);
 440
 441 /*
 442  * Insert a resource into the resource tree. If successful, return NULL,
 443  * otherwise return the conflicting resource (compare to __request_resource())
 444  */
 445 static struct resource * __insert_resource(struct resource *parent, struct resource *new)
 446 {
 447         struct resource *first, *next;
 448
 449         for (;; parent = first) {
 450                 first = __request_resource(parent, new);
 451                 if (!first)
 452                         return first;
 453
 454                 if (first == parent)
 455                         return first;
 456                 if (WARN_ON(first == new))      /* duplicated insertion */
 457                         return first;
 458
 459                 if ((first->start > new->start) || (first->end < new->end))
 460                         break;
 461                 if ((first->start == new->start) && (first->end == new->end))
 462                         break;
 463         }
 464
 465         for (next = first; ; next = next->sibling) {
 466                 /* Partial overlap? Bad, and unfixable */
 467                 if (next->start < new->start || next->end > new->end)
 468                         return next;
 469                 if (!next->sibling)
 470                         break;
 471                 if (next->sibling->start > new->end)
 472                         break;
 473         }
 474
 475         new->parent = parent;
 476         new->sibling = next->sibling;
 477         new->child = first;
 478
 479         next->sibling = NULL;
 480         for (next = first; next; next = next->sibling)
 481                 next->parent = new;
 482
 483         if (parent->child == first) {
 484                 parent->child = new;
 485         } else {
 486                 next = parent->child;
 487                 while (next->sibling != first)
 488                         next = next->sibling;
 489                 next->sibling = new;
 490         }
 491         return NULL;
 492 }
 493
 494 /**
 495  * insert_resource_conflict - Inserts resource in the resource tree
 496  * @parent: parent of the new resource
 497  * @new: new resource to insert
 498  *
 499  * Returns 0 on success, conflict resource if the resource can't be inserted.
 500  *
 501  * This function is equivalent to request_resource_conflict when no conflict
 502  * happens. If a conflict happens, and the conflicting resources
 503  * entirely fit within the range of the new resource, then the new
 504  * resource is inserted and the conflicting resources become children of
 505  * the new resource.
 506  */
 507 struct resource *insert_resource_conflict(struct resource *parent, struct resource *new)
 508 {
 509         struct resource *conflict;
 510
 511         write_lock(&resource_lock);
 512         conflict = __insert_resource(parent, new);
 513         write_unlock(&resource_lock);
 514         return conflict;
 515 }
 516
 517 /**
 518  * insert_resource - Inserts a resource in the resource tree
 519  * @parent: parent of the new resource
 520  * @new: new resource to insert
 521  *
 522  * Returns 0 on success, -EBUSY if the resource can't be inserted.
 523  */
 524 int insert_resource(struct resource *parent, struct resource *new)
 525 {
 526         struct resource *conflict;
 527
 528         conflict = insert_resource_conflict(parent, new);
 529         return conflict ? -EBUSY : 0;
 530 }
 531
 532 /**
 533  * insert_resource_expand_to_fit - Insert a resource into the resource tree
 534  * @root: root resource descriptor
 535  * @new: new resource to insert
 536  *
 537  * Insert a resource into the resource tree, possibly expanding it in order
 538  * to make it encompass any conflicting resources.
 539  */
 540 void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
 541 {
 542         if (new->parent)
 543                 return;
 544
 545         write_lock(&resource_lock);
 546         for (;;) {
 547                 struct resource *conflict;
 548
 549                 conflict = __insert_resource(root, new);
 550                 if (!conflict)
 551                         break;
 552                 if (conflict == root)
 553                         break;
 554
 555                 /* Ok, expand resource to cover the conflict, then try again .. */
 556                 if (conflict->start < new->start)
 557                         new->start = conflict->start;
 558                 if (conflict->end > new->end)
 559                         new->end = conflict->end;
 560
 561                 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
 562         }
 563         write_unlock(&resource_lock);
 564 }
 565
 566 /**
 567  * adjust_resource - modify a resource's start and size
 568  * @res: resource to modify
 569  * @start: new start value
 570  * @size: new size
 571  *
 572  * Given an existing resource, change its start and size to match the
 573  * arguments.  Returns 0 on success, -EBUSY if it can't fit.
 574  * Existing children of the resource are assumed to be immutable.
 575  */
 576 int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
 577 {
 578         struct resource *tmp, *parent = res->parent;
 579         resource_size_t end = start + size - 1;
 580         int result = -EBUSY;
 581
 582         write_lock(&resource_lock);
 583
 584         if ((start < parent->start) || (end > parent->end))
 585                 goto out;
 586
 587         for (tmp = res->child; tmp; tmp = tmp->sibling) {
 588                 if ((tmp->start < start) || (tmp->end > end))
 589                         goto out;
 590         }
 591
 592         if (res->sibling && (res->sibling->start <= end))
 593                 goto out;
 594
 595         tmp = parent->child;
 596         if (tmp != res) {
 597                 while (tmp->sibling != res)
 598                         tmp = tmp->sibling;
 599                 if (start <= tmp->end)
 600                         goto out;
 601         }
 602
 603         res->start = start;
 604         res->end = end;
 605         result = 0;
 606
 607  out:
 608         write_unlock(&resource_lock);
 609         return result;
 610 }
 611
 612 static void __init __reserve_region_with_split(struct resource *root,
 613                 resource_size_t start, resource_size_t end,
 614                 const char *name)
 615 {
 616         struct resource *parent = root;
 617         struct resource *conflict;
 618         struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
 619
 620         if (!res)
 621                 return;
 622
 623         res->name = name;
 624         res->start = start;
 625         res->end = end;
 626         res->flags = IORESOURCE_BUSY;
 627
 628         conflict = __request_resource(parent, res);
 629         if (!conflict)
 630                 return;
 631
 632         /* failed, split and try again */
 633         kfree(res);
 634
 635         /* conflict covered whole area */
 636         if (conflict->start <= start && conflict->end >= end)
 637                 return;
 638
 639         if (conflict->start > start)
 640                 __reserve_region_with_split(root, start, conflict->start-1, name);
 641         if (conflict->end < end)
 642                 __reserve_region_with_split(root, conflict->end+1, end, name);
 643 }
 644
 645 void __init reserve_region_with_split(struct resource *root,
 646                 resource_size_t start, resource_size_t end,
 647                 const char *name)
 648 {
 649         write_lock(&resource_lock);
 650         __reserve_region_with_split(root, start, end, name);
 651         write_unlock(&resource_lock);
 652 }
 653
 654 EXPORT_SYMBOL(adjust_resource);
 655
 656 /**
 657  * resource_alignment - calculate resource's alignment
 658  * @res: resource pointer
 659  *
 660  * Returns alignment on success, 0 (invalid alignment) on failure.
 661  */
 662 resource_size_t resource_alignment(struct resource *res)
 663 {
 664         switch (res->flags & (IORESOURCE_SIZEALIGN | IORESOURCE_STARTALIGN)) {
 665         case IORESOURCE_SIZEALIGN:
 666                 return resource_size(res);
 667         case IORESOURCE_STARTALIGN:
 668                 return res->start;
 669         default:
 670                 return 0;
 671         }
 672 }
 673
 674 /*
 675  * This is compatibility stuff for IO resources.
 676  *
 677  * Note how this, unlike the above, knows about
 678  * the IO flag meanings (busy etc).
 679  *
 680  * request_region creates a new busy region.
 681  *
 682  * check_region returns non-zero if the area is already busy.
 683  *
 684  * release_region releases a matching busy region.
 685  */
 686
 687 static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait);
 688
 689 /**
 690  * __request_region - create a new busy resource region
 691  * @parent: parent resource descriptor
 692  * @start: resource start address
 693  * @n: resource region size
 694  * @name: reserving caller's ID string
 695  * @flags: IO resource flags
 696  */
 697 struct resource * __request_region(struct resource *parent,
 698                                    resource_size_t start, resource_size_t n,
 699                                    const char *name, int flags)
 700 {
 701         DECLARE_WAITQUEUE(wait, current);
 702         struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
 703
 704         if (!res)
 705                 return NULL;
 706
 707         res->name = name;
 708         res->start = start;
 709         res->end = start + n - 1;
 710         res->flags = IORESOURCE_BUSY;
 711         res->flags |= flags;
 712
 713         write_lock(&resource_lock);
 714
 715         for (;;) {
 716                 struct resource *conflict;
 717
 718                 conflict = __request_resource(parent, res);
 719                 if (!conflict)
 720                         break;
 721                 if (conflict != parent) {
 722                         parent = conflict;
 723                         if (!(conflict->flags & IORESOURCE_BUSY))
 724                                 continue;
 725                 }
 726                 if (conflict->flags & flags & IORESOURCE_MUXED) {
 727                         add_wait_queue(&muxed_resource_wait, &wait);
 728                         write_unlock(&resource_lock);
 729                         set_current_state(TASK_UNINTERRUPTIBLE);
 730                         schedule();
 731                         remove_wait_queue(&muxed_resource_wait, &wait);
 732                         write_lock(&resource_lock);
 733                         continue;
 734                 }
 735                 /* Uhhuh, that didn't work out.. */
 736                 kfree(res);
 737                 res = NULL;
 738                 break;
 739         }
 740         write_unlock(&resource_lock);
 741         return res;
 742 }
 743 EXPORT_SYMBOL(__request_region);
 744
 745 /**
 746  * __check_region - check if a resource region is busy or free
 747  * @parent: parent resource descriptor
 748  * @start: resource start address
 749  * @n: resource region size
 750  *
 751  * Returns 0 if the region is free at the moment it is checked,
 752  * returns %-EBUSY if the region is busy.
 753  *
 754  * NOTE:
 755  * This function is deprecated because its use is racy.
 756  * Even if it returns 0, a subsequent call to request_region()
 757  * may fail because another driver etc. just allocated the region.
 758  * Do NOT use it.  It will be removed from the kernel.
 759  */
 760 int __check_region(struct resource *parent, resource_size_t start,
 761                         resource_size_t n)
 762 {
 763         struct resource * res;
 764
 765         res = __request_region(parent, start, n, "check-region", 0);
 766         if (!res)
 767                 return -EBUSY;
 768
 769         release_resource(res);
 770         kfree(res);
 771         return 0;
 772 }
 773 EXPORT_SYMBOL(__check_region);
 774
 775 /**
 776  * __release_region - release a previously reserved resource region
 777  * @parent: parent resource descriptor
 778  * @start: resource start address
 779  * @n: resource region size
 780  *
 781  * The described resource region must match a currently busy region.
 782  */
 783 void __release_region(struct resource *parent, resource_size_t start,
 784                         resource_size_t n)
 785 {
 786         struct resource **p;
 787         resource_size_t end;
 788
 789         p = &parent->child;
 790         end = start + n - 1;
 791
 792         write_lock(&resource_lock);
 793
 794         for (;;) {
 795                 struct resource *res = *p;
 796
 797                 if (!res)
 798                         break;
 799                 if (res->start <= start && res->end >= end) {
 800                         if (!(res->flags & IORESOURCE_BUSY)) {
 801                                 p = &res->child;
 802                                 continue;
 803                         }
 804                         if (res->start != start || res->end != end)
 805                                 break;
 806                         *p = res->sibling;
 807                         write_unlock(&resource_lock);
 808                         if (res->flags & IORESOURCE_MUXED)
 809                                 wake_up(&muxed_resource_wait);
 810                         kfree(res);
 811                         return;
 812                 }
 813                 p = &res->sibling;
 814         }
 815
 816         write_unlock(&resource_lock);
 817
 818         printk(KERN_WARNING "Trying to free nonexistent resource "
 819                 "<%016llx-%016llx>\n", (unsigned long long)start,
 820                 (unsigned long long)end);
 821 }
 822 EXPORT_SYMBOL(__release_region);
 823
 824 /*
 825  * Managed region resource
 826  */
 827 struct region_devres {
 828         struct resource *parent;
 829         resource_size_t start;
 830         resource_size_t n;
 831 };
 832
 833 static void devm_region_release(struct device *dev, void *res)
 834 {
 835         struct region_devres *this = res;
 836
 837         __release_region(this->parent, this->start, this->n);
 838 }
 839
 840 static int devm_region_match(struct device *dev, void *res, void *match_data)
 841 {
 842         struct region_devres *this = res, *match = match_data;
 843
 844         return this->parent == match->parent &&
 845                 this->start == match->start && this->n == match->n;
 846 }
 847
 848 struct resource * __devm_request_region(struct device *dev,
 849                                 struct resource *parent, resource_size_t start,
 850                                 resource_size_t n, const char *name)
 851 {
 852         struct region_devres *dr = NULL;
 853         struct resource *res;
 854
 855         dr = devres_alloc(devm_region_release, sizeof(struct region_devres),
 856                           GFP_KERNEL);
 857         if (!dr)
 858                 return NULL;
 859
 860         dr->parent = parent;
 861         dr->start = start;
 862         dr->n = n;
 863
 864         res = __request_region(parent, start, n, name, 0);
 865         if (res)
 866                 devres_add(dev, dr);
 867         else
 868                 devres_free(dr);
 869
 870         return res;
 871 }
 872 EXPORT_SYMBOL(__devm_request_region);
 873
 874 void __devm_release_region(struct device *dev, struct resource *parent,
 875                            resource_size_t start, resource_size_t n)
 876 {
 877         struct region_devres match_data = { parent, start, n };
 878
 879         __release_region(parent, start, n);
 880         WARN_ON(devres_destroy(dev, devm_region_release, devm_region_match,
 881                                &match_data));
 882 }
 883 EXPORT_SYMBOL(__devm_release_region);
 884
 885 /*
 886  * Called from init/main.c to reserve IO ports.
 887  */
 888 #define MAXRESERVE 4
 889 static int __init reserve_setup(char *str)
 890 {
 891         static int reserved;
 892         static struct resource reserve[MAXRESERVE];
 893
 894         for (;;) {
 895                 unsigned int io_start, io_num;
 896                 int x = reserved;
 897
 898                 if (get_option (&str, &io_start) != 2)
 899                         break;
 900                 if (get_option (&str, &io_num)   == 0)
 901                         break;
 902                 if (x < MAXRESERVE) {
 903                         struct resource *res = reserve + x;
 904                         res->name = "reserved";
 905                         res->start = io_start;
 906                         res->end = io_start + io_num - 1;
 907                         res->flags = IORESOURCE_BUSY;
 908                         res->child = NULL;
 909                         if (request_resource(res->start >= 0x10000 ? &iomem_resource : &ioport_resource, res) == 0)
 910                                 reserved = x+1;
 911                 }
 912         }
 913         return 1;
 914 }
 915
 916 __setup("reserve=", reserve_setup);
 917
 918 /*
 919  * Check if the requested addr and size spans more than any slot in the
 920  * iomem resource tree.
 921  */
 922 int iomem_map_sanity_check(resource_size_t addr, unsigned long size)
 923 {
 924         struct resource *p = &iomem_resource;
 925         int err = 0;
 926         loff_t l;
 927
 928         read_lock(&resource_lock);
 929         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 930                 /*
 931                  * We can probably skip the resources without
 932                  * IORESOURCE_IO attribute?
 933                  */
 934                 if (p->start >= addr + size)
 935                         continue;
 936                 if (p->end < addr)
 937                         continue;
 938                 if (PFN_DOWN(p->start) <= PFN_DOWN(addr) &&
 939                     PFN_DOWN(p->end) >= PFN_DOWN(addr + size - 1))
 940                         continue;
 941                 /*
 942                  * if a resource is "BUSY", it's not a hardware resource
 943                  * but a driver mapping of such a resource; we don't want
 944                  * to warn for those; some drivers legitimately map only
 945                  * partial hardware resources. (example: vesafb)
 946                  */
 947                 if (p->flags & IORESOURCE_BUSY)
 948                         continue;
 949
 950                 printk(KERN_WARNING "resource map sanity check conflict: "
 951                        "0x%llx 0x%llx 0x%llx 0x%llx %s\n",
 952                        (unsigned long long)addr,
 953                        (unsigned long long)(addr + size - 1),
 954                        (unsigned long long)p->start,
 955                        (unsigned long long)p->end,
 956                        p->name);
 957                 err = -1;
 958                 break;
 959         }
 960         read_unlock(&resource_lock);
 961
 962         return err;
 963 }
 964
 965 #ifdef CONFIG_STRICT_DEVMEM
 966 static int strict_iomem_checks = 1;
 967 #else
 968 static int strict_iomem_checks;
 969 #endif
 970
 971 /*
 972  * check if an address is reserved in the iomem resource tree
 973  * returns 1 if reserved, 0 if not reserved.
 974  */
 975 int iomem_is_exclusive(u64 addr)
 976 {
 977         struct resource *p = &iomem_resource;
 978         int err = 0;
 979         loff_t l;
 980         int size = PAGE_SIZE;
 981
 982         if (!strict_iomem_checks)
 983                 return 0;
 984
 985         addr = addr & PAGE_MASK;
 986
 987         read_lock(&resource_lock);
 988         for (p = p->child; p ; p = r_next(NULL, p, &l)) {
 989                 /*
 990                  * We can probably skip the resources without
 991                  * IORESOURCE_IO attribute?
 992                  */
 993                 if (p->start >= addr + size)
 994                         break;
 995                 if (p->end < addr)
 996                         continue;
 997                 if (p->flags & IORESOURCE_BUSY &&
 998                      p->flags & IORESOURCE_EXCLUSIVE) {
 999                         err = 1;
1000                         break;
1001                 }
1002         }
1003         read_unlock(&resource_lock);
1004
1005         return err;
1006 }
1007
1008 static int __init strict_iomem(char *str)
1009 {
1010         if (strstr(str, "relaxed"))
1011                 strict_iomem_checks = 0;
1012         if (strstr(str, "strict"))
1013                 strict_iomem_checks = 1;
1014         return 1;
1015 }
1016
1017 __setup("iomem=", strict_iomem);