firmware: add support to load firmware from dt overlay

fpga-region device tree nodes have the firmware-name property that
contains the file name of firmware in the firmware search path (but not
the path) that shall be loaded before the overlay is applied.

Add the of_firmware_load_overlay() function that accepts an overlay and a
firmware search path, finds the responsible firmware_mgr and loads the
firmware.

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

2 files changed, 87 insertions, 1 deletions

diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 9c6f8de814..b6847752d2 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -6,4 +6,4 @@ obj-y += partition.o
 obj-y += of_net.o
 obj-$(CONFIG_MTD) += of_mtd.o
 obj-$(CONFIG_OF_BAREBOX_DRIVERS) += barebox.o
-obj-$(CONFIG_OF_OVERLAY) += overlay.o resolver.o
+obj-$(CONFIG_OF_OVERLAY) += overlay.o resolver.o of_firmware.o
diff --git a/drivers/of/of_firmware.c b/drivers/of/of_firmware.c
new file mode 100644
index 0000000000..0135631fb8
--- /dev/null
+++ b/drivers/of/of_firmware.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Pengutronix, Michael Tretter <m.tretter@pengutronix.de>
+ */
+#include <common.h>
+#include <firmware.h>
+#include <of.h>
+
+struct overlay_info {
+	const char *firmware_path;
+};
+
+static struct firmware_mgr *of_node_get_mgr(struct device_node *np)
+{
+	struct device_node *mgr_node;
+
+	do {
+		if (of_device_is_compatible(np, "fpga-region")) {
+			mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
+			if (mgr_node)
+				return firmwaremgr_find_by_node(mgr_node);
+		}
+	} while ((np = of_get_parent(np)) != NULL);
+
+	return NULL;
+}
+
+static int load_firmware(struct device_node *target,
+			 struct device_node *fragment, void *data)
+{
+	struct overlay_info *info = data;
+	const char *firmware_name;
+	const char *firmware_path = info->firmware_path;
+	char *firmware;
+	int err;
+	struct firmware_mgr *mgr;
+
+	err = of_property_read_string(fragment,
+				      "firmware-name", &firmware_name);
+	/* Nothing to do if property does not exist. */
+	if (err == -EINVAL)
+		return 0;
+	else if (err)
+		return -EINVAL;
+
+	mgr = of_node_get_mgr(target);
+	if (!mgr)
+		return -EINVAL;
+
+	firmware = basprintf("%s/%s", firmware_path, firmware_name);
+	if (!firmware)
+		return -ENOMEM;
+
+	err = firmwaremgr_load_file(mgr, firmware);
+
+	free(firmware);
+
+	return err;
+}
+
+int of_firmware_load_overlay(struct device_node *overlay, const char *path)
+{
+	struct overlay_info info = {
+		.firmware_path = path,
+	};
+	int err;
+	struct device_node *root;
+	struct device_node *resolved;
+	struct device_node *ovl;
+
+	root = of_get_root_node();
+	/*
+	 * If we cannot resolve the symbols in the overlay, ensure that the
+	 * overlay does depend on firmware to be loaded.
+	 */
+	resolved = of_resolve_phandles(root, overlay);
+	ovl = resolved ? resolved : overlay;
+
+	err = of_process_overlay(root, ovl,
+				 load_firmware, &info);
+
+	if (resolved)
+		of_delete_node(resolved);
+
+	return err;
+}