This driver parse the reboot commands like "reboot loader"
and "reboot recovery" to get a boot mode described in the
device tree , then call the vendor specific write interfae
to store the boot mode in some place like special register
or sram , which can be read by the bootloader after system
reboot.
This is commonly done on Android based devices, in order to
reboot the device into fastboot or recovery mode.
Signed-off-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
---
drivers/misc/Kconfig | 7 ++++
drivers/misc/Makefile | 1 +
drivers/misc/reboot_mode.c | 96 +++++++++++++++++++++++++++++++++++++++++++++
drivers/power/reset/Kconfig | 1 -
include/linux/reboot.h | 4 +-
5 files changed, 107 insertions(+), 2 deletions(-)
create mode 100644 drivers/misc/reboot_mode.c
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 22892c7..039be78 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -525,6 +525,13 @@ config VEXPRESS_SYSCFG
bus. System Configuration interface is one of the possible means
of generating transactions on this bus.
+config REBOOT_MODE
+ tristate
+ depends on OF
+ help
+ This driver will help to communicate the system reboot mode
+ to bootloader
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 537d7f3..6ada5de 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -56,3 +56,4 @@ obj-$(CONFIG_GENWQE) += genwqe/
obj-$(CONFIG_ECHO) += echo/
obj-$(CONFIG_VEXPRESS_SYSCFG) += vexpress-syscfg.o
obj-$(CONFIG_CXL_BASE) += cxl/
+obj-$(CONFIG_REBOOT_MODE) += reboot_mode.o
diff --git a/drivers/misc/reboot_mode.c b/drivers/misc/reboot_mode.c
new file mode 100644
index 0000000..39e3f9f
--- /dev/null
+++ b/drivers/misc/reboot_mode.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2015, Fuzhou Rockchip Electronics Co., Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/reboot.h>
+
+struct mode_info {
+ const char *mode;
+ int magic;
+ struct list_head list;
+};
+
+struct reboot_mode_driver {
+ struct list_head head;
+ int (*write)(int magic);
+ struct notifier_block reboot_notifier;
+};
+
+static int get_reboot_mode_magic(struct reboot_mode_driver *reboot,
+ const char *cmd)
+{
+ int magic = 0;
+ struct mode_info *info;
+
+ if (cmd) {
+ list_for_each_entry(info, &reboot->head, list) {
+ if (!strcmp(info->mode, cmd)) {
+ magic = info->magic;
+ break;
+ }
+ }
+ }
+
+ return magic;
+}
+
+static int reboot_mode_notify(struct notifier_block *this,
+ unsigned long mode, void *cmd)
+{
+ struct reboot_mode_driver *reboot;
+ int magic;
+
+ reboot = container_of(this, struct reboot_mode_driver, reboot_notifier);
+ magic = get_reboot_mode_magic(reboot, cmd);
+ reboot->write(magic);
+
+ return NOTIFY_DONE;
+}
+
+int reboot_mode_register(struct device *dev, int (*write)(int))
+{
+ struct reboot_mode_driver *reboot;
+ struct mode_info *info;
+ struct device_node *child;
+ int ret;
+
+ reboot = devm_kzalloc(dev, sizeof(*reboot), GFP_KERNEL);
+ if (!reboot)
+ return -ENOMEM;
+
+ reboot->write = write;
+ INIT_LIST_HEAD(&reboot->head);
+ for_each_child_of_node(dev->of_node, child) {
+ info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+ info->mode = of_get_property(child, "linux,mode", NULL);
+ if (of_property_read_u32(child, "linux,magic", &info->magic)) {
+ dev_err(dev, "reboot mode %s without magic number\n",
+ info->mode);
+ devm_kfree(dev, info);
+ continue;
+ }
+ list_add_tail(&info->list, &reboot->head);
+ }
+ reboot->reboot_notifier.notifier_call = reboot_mode_notify;
+ ret = register_reboot_notifier(&reboot->reboot_notifier);
+ if (ret)
+ dev_err(dev, "can't register reboot notifier\n");
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(reboot_mode_register);
+
+MODULE_AUTHOR("Andy Yan <andy.yan@xxxxxxxxxxxxxx");
+MODULE_DESCRIPTION("System reboot mode driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index 1131cf7..43521fd 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -172,6 +172,5 @@ config POWER_RESET_ZX
depends on HAS_IOMEM
help
Reboot support for ZTE SoCs.
-
endif
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index a7ff409..f523c32 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -1,7 +1,7 @@
#ifndef _LINUX_REBOOT_H
#define _LINUX_REBOOT_H
-
+#include <linux/device.h>
#include <linux/notifier.h>
#include <uapi/linux/reboot.h>
@@ -42,6 +42,8 @@ extern int register_restart_handler(struct notifier_block *);
extern int unregister_restart_handler(struct notifier_block *);
extern void do_kernel_restart(char *cmd);
+extern int reboot_mode_register(struct device *dev, int (*write)(int));
+
/*
* Architecture-specific implementations of sys_reboot commands.
*/
--
1.9.1
--
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