Introduce fdt_setprop_placeholder() method

In some cases you need to add a property but the contents of it
are not known at creation time, merely the extend of it.

This method allows you to create a property of a given size (filled
with garbage) while a pointer to the property data will be provided.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
[dwg: Corrected commit message]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 17 insertions, 3 deletions

diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index 8b487f6..5c3a2bb 100644
--- a/libfdt/fdt_rw.c
+++ b/libfdt/fdt_rw.c
@@ -269,8 +269,8 @@ int fdt_set_name(void *fdt, int nodeoffset, const char *name)
 	return 0;
 }
 
-int fdt_setprop(void *fdt, int nodeoffset, const char *name,
-		const void *val, int len)
+int fdt_setprop_placeholder(void *fdt, int nodeoffset, const char *name,
+			    int len, void **prop_data)
 {
 	struct fdt_property *prop;
 	int err;
@@ -283,8 +283,22 @@ int fdt_setprop(void *fdt, int nodeoffset, const char *name,
 	if (err)
 		return err;
 
+	*prop_data = prop->data;
+	return 0;
+}
+
+int fdt_setprop(void *fdt, int nodeoffset, const char *name,
+		const void *val, int len)
+{
+	void *prop_data;
+	int err;
+
+	err = fdt_setprop_placeholder(fdt, nodeoffset, name, len, &prop_data);
+	if (err)
+		return err;
+
 	if (len)
-		memcpy(prop->data, val, len);
+		memcpy(prop_data, val, len);
 	return 0;
 }