dm: core: ofnode: Add ofnode_read_bootscript_address()

ofnode_read_bootscript_address() reads bootscript address from
/options/u-boot DT node. bootscr-address or bootscr-ram-offset properties
are read and values are filled. bootscr-address has higher priority than
bootscr-ram-offset and the only one should be described in DT.

Also add test to cover this new function.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/23be3838502efef61803c90ef6e8b32bbd6ede41.1693465140.git.michal.simek@amd.com
diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index 0a85db3..c38596a 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -20,6 +20,7 @@
 struct resource;
 
 #include <dm/ofnode_decl.h>
+#include <linux/errno.h>
 
 struct ofnode_phandle_args {
 	ofnode node;
@@ -1512,6 +1513,26 @@
  */
 const char *ofnode_conf_read_str(const char *prop_name);
 
+/**
+ * ofnode_read_bootscript_address() - Read bootscr-address or bootscr-ram-offset
+ *
+ * @bootscr_address: pointer to 64bit address where bootscr-address property value
+ * is stored
+ * @bootscr_offset:  pointer to 64bit offset address where bootscr-ram-offset
+ * property value is stored
+ *
+ * This reads a bootscr-address or bootscr-ram-offset property from
+ * the /options/u-boot/ node of the devicetree. bootscr-address holds the full
+ * address of the boot script file. bootscr-ram-offset holds the boot script
+ * file offset from the start of the ram base address. When bootscr-address is
+ * defined, bootscr-ram-offset property is ignored.
+ *
+ * This only works with the control FDT.
+ *
+ * Return: 0 if OK, -EINVAL if property is not found.
+ */
+int ofnode_read_bootscript_address(u64 *bootscr_address, u64 *bootscr_offset);
+
 #else /* CONFIG_DM */
 static inline bool ofnode_conf_read_bool(const char *prop_name)
 {
@@ -1528,6 +1549,11 @@
 	return NULL;
 }
 
+static inline int ofnode_read_bootscript_address(u64 *bootscr_address, u64 *bootscr_offset)
+{
+	return -EINVAL;
+}
+
 #endif /* CONFIG_DM */
 
 /**