From 9a6cf73a88ddab2e1ac39088f2806177982cc62c Mon Sep 17 00:00:00 2001
From: David Gibson <david@gibson.dropbear.id.au>
Date: Wed, 20 Aug 2008 16:55:14 +1000
Subject: [PATCH] libfdt: Add function to explicitly expand aliases
Kumar has already added alias expansion to fdt_path_offset().
However, in some circumstances it may be convenient for the user of
libfdt to explicitly get the string expansion of an alias. This patch
adds a function to do this, fdt_get_alias(), and uses it to implement
fdt_path_offset().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
include/libfdt.h | 26 ++++++++++++++++++++++++++
libfdt/fdt_ro.c | 26 +++++++++++++++++++-------
2 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/include/libfdt.h b/include/libfdt.h
index 5492a535207..7cad68c3cef 100644
--- a/include/libfdt.h
+++ b/include/libfdt.h
@@ -458,6 +458,32 @@ static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
*/
uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
+/**
+ * fdt_get_namelen - get alias based on substring
+ * @fdt: pointer to the device tree blob
+ * @name: name of the alias th look up
+ * @namelen: number of characters of name to consider
+ *
+ * Identical to fdt_get_alias(), but only examine the first namelen
+ * characters of name for matching the alias name.
+ */
+const char *fdt_get_alias_namelen(const void *fdt,
+ const char *name, int namelen);
+
+/**
+ * fdt_get_alias - retreive the path referenced by a given alias
+ * @fdt: pointer to the device tree blob
+ * @name: name of the alias th look up
+ *
+ * fdt_get_alias() retrieves the value of a given alias. That is, the
+ * value of the property named 'name' in the node /aliases.
+ *
+ * returns:
+ * a pointer to the expansion of the alias named 'name', of it exists
+ * NULL, if the given alias or the /aliases node does not exist
+ */
+const char *fdt_get_alias(const void *fdt, const char *name);
+
/**
* fdt_get_path - determine the full path of a node
* @fdt: pointer to the device tree blob
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index f559eeda06a..b705f91ecb7 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -145,17 +145,12 @@ int fdt_path_offset(const void *fdt, const char *path)
/* see if we have an alias */
if (*path != '/') {
- const char *q;
- int aliasoffset = fdt_path_offset(fdt, "/aliases");
-
- if (aliasoffset < 0)
- return -FDT_ERR_BADPATH;
+ const char *q = strchr(path, '/');
- q = strchr(path, '/');
if (!q)
q = end;
- p = fdt_getprop_namelen(fdt, aliasoffset, path, q - p, NULL);
+ p = fdt_get_alias_namelen(fdt, p, q - p);
if (!p)
return -FDT_ERR_BADPATH;
offset = fdt_path_offset(fdt, p);
@@ -306,6 +301,23 @@ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
return fdt32_to_cpu(*php);
}
+const char *fdt_get_alias_namelen(const void *fdt,
+ const char *name, int namelen)
+{
+ int aliasoffset;
+
+ aliasoffset = fdt_path_offset(fdt, "/aliases");
+ if (aliasoffset < 0)
+ return NULL;
+
+ return fdt_getprop_namelen(fdt, aliasoffset, name, namelen, NULL);
+}
+
+const char *fdt_get_alias(const void *fdt, const char *name)
+{
+ return fdt_get_alias_namelen(fdt, name, strlen(name));
+}
+
int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
{
int pdepth = 0, p = 0;
--
2.42.0