[POWERPC] bootwrapper: Add get_path()

This will be used by the PlanetCore firmware support to construct
a linux,stdout-path from the serial node that it finds.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 59 insertions, 0 deletions

diff --git a/arch/powerpc/boot/flatdevtree.c b/arch/powerpc/boot/flatdevtree.c
index 0af7291fc67c..cf30675c6116 100644
--- a/arch/powerpc/boot/flatdevtree.c
+++ b/arch/powerpc/boot/flatdevtree.c
@@ -975,3 +975,62 @@ void *ft_create_node(struct ft_cxt *cxt, const void *parent, const char *name)
         }
         return NULL;
 }
+
+/* Returns the start of the path within the provided buffer, or NULL on
+ * error.
+ */
+char *ft_get_path(struct ft_cxt *cxt, const void *phandle,
+                  char *buf, int len)
+{
+        const char *path_comp[FT_MAX_DEPTH];
+        struct ft_atom atom;
+        char *p, *next, *pos;
+        int depth = 0, i;
+        void *node;
+
+        node = ft_node_ph2node(cxt, phandle);
+        if (node == NULL)
+                return NULL;
+
+        p = ft_root_node(cxt);
+
+        while ((next = ft_next(cxt, p, &atom)) != NULL) {
+                switch (atom.tag) {
+                case OF_DT_BEGIN_NODE:
+                        path_comp[depth++] = atom.name;
+                        if (p == node)
+                                goto found;
+
+                        break;
+
+                case OF_DT_END_NODE:
+                        if (--depth == 0)
+                                return NULL;
+                }
+
+                p = next;
+        }
+
+found:
+        pos = buf;
+        for (i = 1; i < depth; i++) {
+                int this_len;
+
+                if (len <= 1)
+                        return NULL;
+
+                *pos++ = '/';
+                len--;
+
+                strncpy(pos, path_comp[i], len);
+
+                if (pos[len - 1] != 0)
+                        return NULL;
+
+                this_len = strlen(pos);
+                len -= this_len;
+                pos += this_len;
+        }
+
+        return buf;
+}