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, then the bootloader can take different action according to the mode stored. This is commonly used on Android based devices, in order to reboot the device into fastboot or recovery mode. Signed-off-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx> --- Changes in v1: None drivers/misc/Kconfig | 7 ++++ drivers/misc/Makefile | 1 + drivers/misc/reboot_mode.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/reboot.h | 4 +- 4 files changed, 107 insertions(+), 1 deletion(-) create mode 100644 drivers/misc/reboot_mode.c diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 22892c7..0cceb74 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 pass 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..16bbaab --- /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/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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html