of/promtree: add package-to-path support to pdt

package-to-path is a PROM function which tells us the real (full) name of the
node.  This provides a hook for that in the prom ops struct, and makes use
of it in the pdt code when attempting to determine a node's name.  If the
hook is available, try using it (falling back to looking at the "name"
property if it fails).

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 45 insertions, 1 deletions

diff --git a/drivers/of/pdt.c b/drivers/of/pdt.c
index 31a4fb8694db..28295d0a50f6 100644
--- a/drivers/of/pdt.c
+++ b/drivers/of/pdt.c
@@ -132,6 +132,47 @@ static char * __init of_pdt_get_one_property(phandle node, const char *name)
         return buf;
 }
 
+static char * __init of_pdt_try_pkg2path(phandle node)
+{
+        char *res, *buf = NULL;
+        int len;
+
+        if (!of_pdt_prom_ops->pkg2path)
+                return NULL;
+
+        if (of_pdt_prom_ops->pkg2path(node, buf, 0, &len))
+                return NULL;
+        buf = prom_early_alloc(len + 1);
+        if (of_pdt_prom_ops->pkg2path(node, buf, len, &len)) {
+                pr_err("%s: package-to-path failed\n", __func__);
+                return NULL;
+        }
+
+        res = strrchr(buf, '/');
+        if (!res) {
+                pr_err("%s: couldn't find / in %s\n", __func__, buf);
+                return NULL;
+        }
+        return res+1;
+}
+
+/*
+ * When fetching the node's name, first try using package-to-path; if
+ * that fails (either because the arch hasn't supplied a PROM callback,
+ * or some other random failure), fall back to just looking at the node's
+ * 'name' property.
+ */
+static char * __init of_pdt_build_name(phandle node)
+{
+        char *buf;
+
+        buf = of_pdt_try_pkg2path(node);
+        if (!buf)
+                buf = of_pdt_get_one_property(node, "name");
+
+        return buf;
+}
+
 static struct device_node * __init of_pdt_create_node(phandle node,
                                                     struct device_node *parent)
 {
@@ -146,7 +187,7 @@ static struct device_node * __init of_pdt_create_node(phandle node,
 
         kref_init(&dp->kref);
 
-        dp->name = of_pdt_get_one_property(node, "name");
+        dp->name = of_pdt_build_name(node);
         dp->type = of_pdt_get_one_property(node, "device_type");
         dp->phandle = node;
 
diff --git a/include/linux/of_pdt.h b/include/linux/of_pdt.h
index 0f7d0c56348a..c65a18a0cfdf 100644
--- a/include/linux/of_pdt.h
+++ b/include/linux/of_pdt.h
@@ -29,6 +29,9 @@ struct of_pdt_ops {
         /* phandles are 0 if no child or sibling exists */
         phandle (*getchild)(phandle parent);
         phandle (*getsibling)(phandle node);
+
+        /* return 0 on success; fill in 'len' with number of bytes in path */
+        int (*pkg2path)(phandle node, char *buf, const int buflen, int *len);
 };
 
 extern void *prom_early_alloc(unsigned long size);