blspec: load firmware if specified in dt overlay

If a device tree overlay referenced by the blspec depends on firmware,
try to load the firmware from the default Linux firmware search path
/lib/firmware in the about to be started rootfs.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 17 insertions, 0 deletions

diff --git a/common/blspec.c b/common/blspec.c
index fbba2fc78c..7c27e0b869 100644
--- a/common/blspec.c
+++ b/common/blspec.c
@@ -14,6 +14,7 @@
 
 #include <environment.h>
 #include <globalvar.h>
+#include <firmware.h>
 #include <readkey.h>
 #include <common.h>
 #include <driver.h>
@@ -49,6 +50,7 @@ static int blspec_apply_oftree_overlay(char *file, const char *abspath,
 	struct fdt_header *fdt;
 	struct device_node *overlay;
 	char *path;
+	char *firmware_path;
 
 	path = basprintf("%s/%s", abspath, file);
 
@@ -72,6 +74,21 @@ static int blspec_apply_oftree_overlay(char *file, const char *abspath,
 		goto out;
 	}
 
+	/*
+	 * Unfortunately the device tree overlay contains only the filename of
+	 * the firmware and relies on the firmware search paths to find the
+	 * actual file. Use /lib/firmware in the Linux root directory and hope
+	 * for the best.
+	 */
+	firmware_path = basprintf("%s/%s", abspath, "/lib/firmware");
+	ret = of_firmware_load_overlay(overlay, firmware_path);
+	free(firmware_path);
+	if (ret) {
+		pr_warn("failed to load firmware: skip overlay \"%s\"\n", path);
+		of_delete_node(overlay);
+		goto out;
+	}
+
 	ret = of_register_overlay(overlay);
 	if (ret) {
 		pr_warn("cannot register devicetree overlay \"%s\"\n", path);