[PATCH 10/17] overlay: Add of_overlay_apply_file()

[Sascha Hauer]

A shortcut to of_overlay_apply_tree() which takes a filename rather than
an unflattened device tree.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 drivers/of/overlay.c | 35 +++++++++++++++++++++++++++++++++++
 include/of.h         |  7 +++++++
 2 files changed, 42 insertions(+)

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 7a89cbe948..c9ede614a6 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -14,6 +14,8 @@
 #include <globalvar.h>
 #include <magicvar.h>
 #include <string.h>
+#include <libfile.h>
+#include <fs.h>
 
 static struct device_node *find_target(struct device_node *root,
 				       struct device_node *fragment)
@@ -224,6 +226,39 @@ int of_overlay_apply_tree(struct device_node *root,
 	return err;
 }
 
+int of_overlay_apply_file(struct device_node *root, const char *filename)
+{
+	void *fdt;
+	struct device_node *ovl;
+	size_t size;
+	int ret;
+
+	ret = read_file_2(filename, &size, &fdt, FILESIZE_MAX);
+	if (ret)
+		return ret;
+
+	ovl = of_unflatten_dtb(fdt, size);
+
+	free(fdt);
+
+	if (IS_ERR(ovl)) {
+		pr_err("Failed to unflatten %s: %pe\n", filename, ovl);
+		return PTR_ERR(ovl);
+	}
+
+	ret = of_overlay_apply_tree(root, ovl);
+	if (ret == -ENODEV)
+		pr_debug("Not applied %s (not compatible)\n", filename);
+	else if (ret)
+		pr_err("Cannot apply %s: %s\n", filename, strerror(-ret));
+	else
+		pr_info("Applied %s\n", filename);
+
+	of_delete_node(ovl);
+
+	return ret;
+}
+
 static int of_overlay_fixup(struct device_node *root, void *data)
 {
 	struct device_node *overlay = data;
diff --git a/include/of.h b/include/of.h
index 74b82ae003..e43e225338 100644
--- a/include/of.h
+++ b/include/of.h
@@ -1025,6 +1025,7 @@ struct device_node *of_resolve_phandles(struct device_node *root,
 					const struct device_node *overlay);
 int of_overlay_apply_tree(struct device_node *root,
 			  struct device_node *overlay);
+int of_overlay_apply_file(struct device_node *root, const char *filename);
 int of_register_overlay(struct device_node *overlay);
 int of_process_overlay(struct device_node *root,
 		    struct device_node *overlay,
@@ -1046,6 +1047,12 @@ static inline int of_overlay_apply_tree(struct device_node *root,
 	return -ENOSYS;
 }
 
+static inline int of_overlay_apply_file(struct device_node *root,
+					const char *filename)
+{
+	return -ENOSYS;
+}
+
 static inline int of_register_overlay(struct device_node *overlay)
 {
 	return -ENOSYS;
-- 
2.29.2