libfdt: Add support for using aliases in fdt_path_offset()

If the path doesn't start with '/' check to see if it matches some alias
under "/aliases" and substitute the matching alias value in the path
and retry the lookup.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Gerald Van Baren <vanbaren@cideas.com>

diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index d566eba274450849ba87cc361524ab1098dd7cbf..b09a6e9eb7e5976333d6e4626f67102074dabdd8 100644 (file)
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -143,8 +143,25 @@ int fdt_path_offset(const void *fdt, const char *path)
 
        FDT_CHECK_HEADER(fdt);
 
-       if (*path != '/')
-               return -FDT_ERR_BADPATH;
+       /* 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;
+
+               q = strchr(path, '/');
+               if (!q)
+                       q = end;
+
+               p = fdt_getprop_namelen(fdt, aliasoffset, path, q - p, NULL);
+               if (!p)
+                       return -FDT_ERR_BADPATH;
+               offset = fdt_path_offset(fdt, p);
+
+               p = q;
+       }
 
        while (*p) {
                const char *q;