dt: add of_alias_scan and of_alias_get_id

The patch adds function of_alias_scan to populate a global lookup
table with the properties of 'aliases' node and function
of_alias_get_id for drivers to find alias id from the lookup table.

v3: Split out automatic addition of aliases on id lookup so that it can be
    debated separately from the core functionality.
v2: - Add of_chosen/of_aliases populating and of_alias_scan() invocation
    for OF_PROMTREE.
    - Add locking
    - rework parse loop

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/of/pdt.c b/drivers/of/pdt.c
index 4d87b5dc9284..bc5b3990f6ed 100644
--- a/drivers/of/pdt.c
+++ b/drivers/of/pdt.c
@@ -229,6 +229,11 @@ static struct device_node * __init of_pdt_build_tree(struct device_node *parent,
         return ret;
 }
 
+static void *kernel_tree_alloc(u64 size, u64 align)
+{
+        return prom_early_alloc(size);
+}
+
 void __init of_pdt_build_devicetree(phandle root_node, struct of_pdt_ops *ops)
 {
         struct device_node **nextp;
@@ -245,4 +250,7 @@ void __init of_pdt_build_devicetree(phandle root_node, struct of_pdt_ops *ops)
         nextp = &allnodes->allnext;
         allnodes->child = of_pdt_build_tree(allnodes,
                         of_pdt_prom_ops->getchild(allnodes->phandle), &nextp);
+
+        /* Get pointer to "/chosen" and "/aliasas" nodes for use everywhere */
+        of_alias_scan(kernel_tree_alloc);
 }