[PATCH 2/2] wrapper: Treat NULL as root node in devp_offset; add devp_offset_find().

[Scott Wood]

Many operations, as currently used in the wrapper, assume they can
pass NULL and have it be treated as the root node.  However, libfdt-wrapper
converts NULL to -1, which is only appropriate when searching for nodes,
and will cause an error otherwise.

Signed-off-by: Scott Wood <scottwood at freescale.com>
---
 arch/powerpc/boot/libfdt-wrapper.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/boot/libfdt-wrapper.c b/arch/powerpc/boot/libfdt-wrapper.c
index 868c504..97af36c 100644
--- a/arch/powerpc/boot/libfdt-wrapper.c
+++ b/arch/powerpc/boot/libfdt-wrapper.c
@@ -48,7 +48,8 @@
 		check_err(_offset) ? NULL : (void *)(_offset+1); \
 	})
 
-#define devp_offset(devp)	(((int)(devp))-1)
+#define devp_offset_find(devp)	(((int)(devp))-1)
+#define devp_offset(devp)	(devp ? ((int)(devp))-1 : 0)
 
 static void *fdt;
 static void *buf; /* = NULL */
@@ -127,8 +128,9 @@ static void *fdt_wrapper_find_node_by_prop_value(const void *prev,
 						 const char *val,
 						 int len)
 {
-	return offset_devp(fdt_node_offset_by_prop_value(fdt, devp_offset(prev),
-							 name, val, len));
+	int offset = fdt_node_offset_by_prop_value(fdt, devp_offset_find(prev),
+	                                           name, val, len);
+	return offset_devp(offset);
 }
 
 static char *fdt_wrapper_get_path(const void *devp, char *buf, int len)
-- 
1.5.3.7