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 ---

Another patch hot off the dtc/libfdt repository.

gvb

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 5492a53..7cad68c 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -459,6 +459,32 @@ 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 * @nodeoffset: offset of the node whose path to find diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c index f559eed..b705f91 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;