This method returns the length of the full path of the node so that
it may be used without having to call fdt_get_path() using a worst
case sized buffer.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
---
libfdt/fdt_ro.c | 28 ++++++++++++++++++++++++++++
libfdt/libfdt.h | 22 ++++++++++++++++++++++
2 files changed, 50 insertions(+)
diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
index 08de2cc..8b67f2f 100644
--- a/libfdt/fdt_ro.c
+++ b/libfdt/fdt_ro.c
@@ -438,6 +438,34 @@ int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen)
return offset; /* error from fdt_next_node() */
}
+int fdt_get_path_len(const void *fdt, int nodeoffset)
+{
+ int len = 0, namelen;
+ const char *name;
+
+ FDT_CHECK_HEADER(fdt);
+
+ for (;;) {
+ name = fdt_get_name(fdt, nodeoffset, &namelen);
+ if (!name)
+ return namelen;
+
+ /* root? we're done */
+ if (namelen == 0)
+ break;
+
+ nodeoffset = fdt_parent_offset(fdt, nodeoffset);
+ if (nodeoffset < 0)
+ return nodeoffset;
+ len += namelen + 1;
+ }
+
+ /* in case of root pretend it's "/" */
+ if (len == 0)
+ len++;
+ return len;
+}
+
int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
int supernodedepth, int *nodedepth)
{
diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
index e01c645..2c0b570 100644
--- a/libfdt/libfdt.h
+++ b/libfdt/libfdt.h
@@ -765,6 +765,28 @@ const char *fdt_get_alias(const void *fdt, const char *name);
int fdt_get_path(const void *fdt, int nodeoffset, char *buf, int buflen);
/**
+ * fdt_get_path_len - determine the length of the full path of a node
+ * @fdt: pointer to the device tree blob
+ * @nodeoffset: offset of the node whose path to find
+ *
+ * fdt_get_path_len() computes the size of the full path of the node at
+ * offset nodeoffset.
+ *
+ * NOTE: This function is expensive, as it must scan the device tree
+ * structure from the start to nodeoffset.
+ *
+ * returns:
+ * > 0, on success
+ * length of the full path of the node
+ * -FDT_ERR_BADOFFSET, nodeoffset does not refer to a BEGIN_NODE tag
+ * -FDT_ERR_BADMAGIC,
+ * -FDT_ERR_BADVERSION,
+ * -FDT_ERR_BADSTATE,
+ * -FDT_ERR_BADSTRUCTURE, standard meanings
+ */
+int fdt_get_path_len(const void *fdt, int nodeoffset);
+
+/**
* fdt_supernode_atdepth_offset - find a specific ancestor of a node
* @fdt: pointer to the device tree blob
* @nodeoffset: offset of the node whose parent to find
--
2.1.4
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