[PATCH 1/3] firmware: of: populate /firmware/ node during init

[Sudeep Holla]

Since "/firmware" does not have its own "compatible" property as it's
just collection of nodes representing firmware interface, it's sub-nodes
are not populated during system initialization.

Currently different firmware drivers search the /firmware/ node and
populate the sub-node devices selectively. Instead we can populate
the /firmware/ node during init to avoid more drivers continuing to
populate the devices selectively.

This patch adds initcall to achieve the same.

Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
 drivers/firmware/Makefile |  1 +
 drivers/firmware/of.c     | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 drivers/firmware/of.c

diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 91d3ff62c653..d9a6fce43613 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_ISCSI_IBFT)	+= iscsi_ibft.o
 obj-$(CONFIG_FIRMWARE_MEMMAP)	+= memmap.o
 obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
 obj-$(CONFIG_FW_CFG_SYSFS)	+= qemu_fw_cfg.o
+obj-$(CONFIG_OF)		+= of.o
 obj-$(CONFIG_QCOM_SCM)		+= qcom_scm.o
 obj-$(CONFIG_QCOM_SCM_64)	+= qcom_scm-64.o
 obj-$(CONFIG_QCOM_SCM_32)	+= qcom_scm-32.o
diff --git a/drivers/firmware/of.c b/drivers/firmware/of.c
new file mode 100644
index 000000000000..149b9660fb44
--- /dev/null
+++ b/drivers/firmware/of.c
@@ -0,0 +1,34 @@
+/*
+ * Populates the nodes under /firmware/ device tree node
+ *
+ * Copyright (C) 2017 ARM Ltd.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Released under the GPLv2 only.
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+
+static int __init firmware_of_init(void)
+{
+	struct device_node *fw_np;
+	int ret;
+
+	fw_np = of_find_node_by_name(NULL, "firmware");
+
+	if (!fw_np)
+		return 0;
+
+	ret = of_platform_populate(fw_np, NULL, NULL, NULL);
+
+	of_node_put(fw_np);
+
+	return ret;
+}
+arch_initcall_sync(firmware_of_init);
-- 
2.7.4