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>
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@ -458,6 +458,32 @@ static inline void *fdt_getprop_w(void *fdt, int nodeoffset,
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*/
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uint32_t fdt_get_phandle(const void *fdt, int nodeoffset);
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/**
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* fdt_get_namelen - get alias based on substring
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* @fdt: pointer to the device tree blob
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* @name: name of the alias th look up
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* @namelen: number of characters of name to consider
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*
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* Identical to fdt_get_alias(), but only examine the first namelen
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* characters of name for matching the alias name.
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*/
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const char *fdt_get_alias_namelen(const void *fdt,
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const char *name, int namelen);
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/**
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* fdt_get_alias - retreive the path referenced by a given alias
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* @fdt: pointer to the device tree blob
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* @name: name of the alias th look up
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*
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* fdt_get_alias() retrieves the value of a given alias. That is, the
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* value of the property named 'name' in the node /aliases.
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*
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* returns:
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* a pointer to the expansion of the alias named 'name', of it exists
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* NULL, if the given alias or the /aliases node does not exist
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*/
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const char *fdt_get_alias(const void *fdt, const char *name);
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/**
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* fdt_get_path - determine the full path of a node
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* @fdt: pointer to the device tree blob
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@ -145,17 +145,12 @@ int fdt_path_offset(const void *fdt, const char *path)
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/* see if we have an alias */
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if (*path != '/') {
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const char *q;
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int aliasoffset = fdt_path_offset(fdt, "/aliases");
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const char *q = strchr(path, '/');
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if (aliasoffset < 0)
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return -FDT_ERR_BADPATH;
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q = strchr(path, '/');
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if (!q)
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q = end;
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p = fdt_getprop_namelen(fdt, aliasoffset, path, q - p, NULL);
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p = fdt_get_alias_namelen(fdt, p, q - p);
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if (!p)
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return -FDT_ERR_BADPATH;
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offset = fdt_path_offset(fdt, p);
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@ -306,6 +301,23 @@ uint32_t fdt_get_phandle(const void *fdt, int nodeoffset)
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return fdt32_to_cpu(*php);
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}
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const char *fdt_get_alias_namelen(const void *fdt,
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const char *name, int namelen)
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{
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int aliasoffset;
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aliasoffset = fdt_path_offset(fdt, "/aliases");
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if (aliasoffset < 0)
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return NULL;
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return fdt_getprop_namelen(fdt, aliasoffset, name, namelen, NULL);
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}
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const char *fdt_get_alias(const void *fdt, const char *name)
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{
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return fdt_get_alias_namelen(fdt, name, strlen(name));
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}
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int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
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{
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int pdepth = 0, p = 0;
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