firmware/raspberrypi: Notify firmware of a reboot

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

Register for reboot notifications, sending RPI_FIRMWARE_NOTIFY_REBOOT
over the mailbox interface on reception.
Signed-off-by: NPhil Elwell <phil@raspberrypi.org>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/firmware/raspberrypi.c

@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/reboot.h>
 #include <linux/slab.h>
 #include <soc/bcm2835/raspberrypi-firmware.h>
 
@@ -177,6 +178,26 @@ int rpi_firmware_property(struct rpi_firmware *fw,
 }
 EXPORT_SYMBOL_GPL(rpi_firmware_property);
 
+static int rpi_firmware_notify_reboot(struct notifier_block *nb,
+				      unsigned long action,
+				      void *data)
+{
+	struct rpi_firmware *fw;
+	struct platform_device *pdev = g_pdev;
+
+	if (!pdev)
+		return 0;
+
+	fw = platform_get_drvdata(pdev);
+	if (!fw)
+		return 0;
+
+	(void)rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT,
+				    0, 0);
+
+	return 0;
+}
+
 static void
 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 {
@@ -318,15 +339,32 @@ static struct platform_driver rpi_firmware_driver = {
 	.remove		= rpi_firmware_remove,
 };
 
+static struct notifier_block rpi_firmware_reboot_notifier = {
+	.notifier_call = rpi_firmware_notify_reboot,
+};
+
 static int __init rpi_firmware_init(void)
 {
-	return platform_driver_register(&rpi_firmware_driver);
+	int ret = register_reboot_notifier(&rpi_firmware_reboot_notifier);
+	if (ret)
+		goto out1;
+	ret = platform_driver_register(&rpi_firmware_driver);
+	if (ret)
+		goto out2;
+
+	return 0;
+
+out2:
+	unregister_reboot_notifier(&rpi_firmware_reboot_notifier);
+out1:
+	return ret;
 }
 subsys_initcall(rpi_firmware_init);
 
 static void __init rpi_firmware_exit(void)
 {
 	platform_driver_unregister(&rpi_firmware_driver);
+	unregister_reboot_notifier(&rpi_firmware_reboot_notifier);
 }
 module_exit(rpi_firmware_exit);