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>
This commit is contained in:
David Gibson 2008-08-20 16:55:14 +10:00 committed by Gerald Van Baren
parent 3e38577208
commit 9a6cf73a88
2 changed files with 45 additions and 7 deletions

View File

@ -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

View File

@ -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");
const char *q = strchr(path, '/');
if (aliasoffset < 0)
return -FDT_ERR_BADPATH;
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;