target/linux/brcm63xx/patches-3.14/003-of-Make-of_find_node_by_path-handle-aliases.patch

   1 From c22e650e66b862babe9c00bebb20b8029c7b0362 Mon Sep 17 00:00:00 2001
   2 From: Grant Likely <grant.likely@linaro.org>
   3 Date: Fri, 14 Mar 2014 17:07:12 +0000
   4 Subject: [PATCH] of: Make of_find_node_by_path() handle /aliases
   5
   6 Make of_find_node_by_path() handle aliases as prefixes. To make this
   7 work the name search is refactored to search by path component instead
   8 of by full string. This should be a more efficient search, and it makes
   9 it possible to start a search at a subnode of a tree.
  10
  11 Signed-off-by: David Daney <david.daney@cavium.com>
  12 Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
  13 [grant.likely: Rework to not require allocating at runtime]
  14 Acked-by: Rob Herring <robh@kernel.org>
  15 Signed-off-by: Grant Likely <grant.likely@linaro.org>
  16 ---
  17  drivers/of/base.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
  18  1 file changed, 61 insertions(+), 6 deletions(-)
  19
  20 --- a/drivers/of/base.c
  21 +++ b/drivers/of/base.c
  22 @@ -633,23 +633,78 @@ struct device_node *of_get_child_by_name
  23  }
  24  EXPORT_SYMBOL(of_get_child_by_name);
  25
  26 +static struct device_node *__of_find_node_by_path(struct device_node *parent,
  27 +                                               const char *path)
  28 +{
  29 +       struct device_node *child;
  30 +       int len = strchrnul(path, '/') - path;
  31 +
  32 +       if (!len)
  33 +               return NULL;
  34 +
  35 +       __for_each_child_of_node(parent, child) {
  36 +               const char *name = strrchr(child->full_name, '/');
  37 +               if (WARN(!name, "malformed device_node %s\n", child->full_name))
  38 +                       continue;
  39 +               name++;
  40 +               if (strncmp(path, name, len) == 0 && (strlen(name) == len))
  41 +                       return child;
  42 +       }
  43 +       return NULL;
  44 +}
  45 +
  46  /**
  47   *     of_find_node_by_path - Find a node matching a full OF path
  48 - *     @path:  The full path to match
  49 + *     @path: Either the full path to match, or if the path does not
  50 + *            start with '/', the name of a property of the /aliases
  51 + *            node (an alias).  In the case of an alias, the node
  52 + *            matching the alias' value will be returned.
  53 + *
  54 + *     Valid paths:
  55 + *             /foo/bar        Full path
  56 + *             foo             Valid alias
  57 + *             foo/bar         Valid alias + relative path
  58   *
  59   *     Returns a node pointer with refcount incremented, use
  60   *     of_node_put() on it when done.
  61   */
  62  struct device_node *of_find_node_by_path(const char *path)
  63  {
  64 -       struct device_node *np = of_allnodes;
  65 +       struct device_node *np = NULL;
  66 +       struct property *pp;
  67         unsigned long flags;
  68
  69 +       if (strcmp(path, "/") == 0)
  70 +               return of_node_get(of_allnodes);
  71 +
  72 +       /* The path could begin with an alias */
  73 +       if (*path != '/') {
  74 +               char *p = strchrnul(path, '/');
  75 +               int len = p - path;
  76 +
  77 +               /* of_aliases must not be NULL */
  78 +               if (!of_aliases)
  79 +                       return NULL;
  80 +
  81 +               for_each_property_of_node(of_aliases, pp) {
  82 +                       if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
  83 +                               np = of_find_node_by_path(pp->value);
  84 +                               break;
  85 +                       }
  86 +               }
  87 +               if (!np)
  88 +                       return NULL;
  89 +               path = p;
  90 +       }
  91 +
  92 +       /* Step down the tree matching path components */
  93         raw_spin_lock_irqsave(&devtree_lock, flags);
  94 -       for (; np; np = np->allnext) {
  95 -               if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
  96 -                   && of_node_get(np))
  97 -                       break;
  98 +       if (!np)
  99 +               np = of_node_get(of_allnodes);
 100 +       while (np && *path == '/') {
 101 +               path++; /* Increment past '/' delimiter */
 102 +               np = __of_find_node_by_path(np, path);
 103 +               path = strchrnul(path, '/');
 104         }
 105         raw_spin_unlock_irqrestore(&devtree_lock, flags);
 106         return np;