target/linux/lantiq/patches-3.0/995-backport-3.1-lookup_resource.patch

   1 commit 1c388919d89ca35741e9c4d3255adf87f76f0c06
   2 Author: Geert Uytterhoeven <geert@linux-m68k.org>
   3 Date:   Sat May 7 20:53:16 2011 +0200
   4
   5     resources: Add lookup_resource()
   6
   7     Add a function to find an existing resource by a resource start address.
   8     This allows to implement simple allocators (with a malloc/free-alike API)
   9     on top of the resource system.
  10
  11     Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
  12
  13 diff --git a/include/linux/ioport.h b/include/linux/ioport.h
  14 index e9bb22c..63eb429 100644
  15 --- a/include/linux/ioport.h
  16 +++ b/include/linux/ioport.h
  17 @@ -132,6 +132,7 @@ extern int allocate_resource(struct resource *root, struct resource *new,
  18                                                        resource_size_t,
  19                                                        resource_size_t),
  20                              void *alignf_data);
  21 +struct resource *lookup_resource(struct resource *root, resource_size_t start);
  22  int adjust_resource(struct resource *res, resource_size_t start,
  23                     resource_size_t size);
  24  resource_size_t resource_alignment(struct resource *res);
  25 diff --git a/kernel/resource.c b/kernel/resource.c
  26 index 3ff4017..3b3cedc 100644
  27 --- a/kernel/resource.c
  28 +++ b/kernel/resource.c
  29 @@ -553,6 +553,27 @@ int allocate_resource(struct resource *root, struct resource *new,
  30
  31  EXPORT_SYMBOL(allocate_resource);
  32
  33 +/**
  34 + * lookup_resource - find an existing resource by a resource start address
  35 + * @root: root resource descriptor
  36 + * @start: resource start address
  37 + *
  38 + * Returns a pointer to the resource if found, NULL otherwise
  39 + */
  40 +struct resource *lookup_resource(struct resource *root, resource_size_t start)
  41 +{
  42 +       struct resource *res;
  43 +
  44 +       read_lock(&resource_lock);
  45 +       for (res = root->child; res; res = res->sibling) {
  46 +               if (res->start == start)
  47 +                       break;
  48 +       }
  49 +       read_unlock(&resource_lock);
  50 +
  51 +       return res;
  52 +}
  53 +
  54  /*
  55   * Insert a resource into the resource tree. If successful, return NULL,
  56   * otherwise return the conflicting resource (compare to __request_resource())