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Re: [RFC PATCH v3 2/6] of: Make of_find_node_by_path() traverse /aliases

To: David Daney <ddaney@caviumnetworks.com>
Subject: Re: [RFC PATCH v3 2/6] of: Make of_find_node_by_path() traverse /aliases for relative paths.
From: Sergei Shtylyov <sshtylyov@mvista.com>
Date: Fri, 06 May 2011 14:05:48 +0400
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org, devicetree-discuss@lists.ozlabs.org, grant.likely@secretlab.ca, linux-kernel@vger.kernel.org
In-reply-to: <1304614949-30460-3-git-send-email-ddaney@caviumnetworks.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1304614949-30460-1-git-send-email-ddaney@caviumnetworks.com> <1304614949-30460-3-git-send-email-ddaney@caviumnetworks.com>
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Hello.

On 05-05-2011 21:02, David Daney wrote:

Currently all paths passed to of_find_node_by_path() must begin with a
'/', indicating a full path to the desired node.

Augment the look-up code so that if a path does *not* begin with '/',
the path is used as the name of an /aliases property.  The value of
this alias is then used as the full node path to be found.

Signed-off-by: David Daney<ddaney@caviumnetworks.com>
---
  drivers/of/base.c |   41 ++++++++++++++++++++++++++++++++++++++++-
  1 files changed, 40 insertions(+), 1 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 632ebae..1a0a83e 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
[...]
@@ -348,14 +351,50 @@ EXPORT_SYMBOL(of_get_next_child);
  struct device_node *of_find_node_by_path(const char *path)
  {
        struct device_node *np = allnodes;
+       struct device_node *aliases = NULL;
+       char *alias = NULL;
+       char *new_path = NULL;

        read_lock(&devtree_lock);
+
+       if (path[0] != '/') {
+               const char *ps;
+               aliases = of_find_node_by_path("/aliases");
+               if (!aliases)
+                       goto out;
+
+               ps = strchr(path, '/');
+               if (ps) {
+                       size_t len = ps - path;
+                       alias = kmalloc(len + 1, GFP_KERNEL);

   How about error handling?

+                       strncpy(alias, path, len);
+                       alias[len] = 0;
+                       path = of_get_property(aliases, alias, NULL);
+                       if (!path)
+                               goto out;
+                       len = strlen(path) + strlen(ps) + 1;
+                       new_path = kmalloc(len, GFP_KERNEL);

   Here too...

WBR, Sergei

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