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 <[email protected]> --- 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 <[email protected]"); +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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
