diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/power/reset/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/power/reset/Makefile | 1 | ||||
| -rw-r--r-- | drivers/power/reset/qemu-virt-ctrl.c | 122 |
3 files changed, 133 insertions, 0 deletions
diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig index f6c1bcbb57de..99e3334726a5 100644 --- a/drivers/power/reset/Kconfig +++ b/drivers/power/reset/Kconfig @@ -354,4 +354,14 @@ config POWER_MLXBF help This driver supports reset or low power mode handling for Mellanox BlueField. +config POWER_RESET_QEMU_VIRT_CTRL + tristate "QEMU Virt Machine System Controller" + depends on HAS_IOMEM + help + This driver supports the system reset and power off functionality + provided by the QEMU 'virt-ctrl' device. + + Say Y here if you are running Linux on a QEMU virtual machine that + provides this controller, such as the m68k virt machine. + endif diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile index 0e4ae6f6b5c5..d7ae97241a83 100644 --- a/drivers/power/reset/Makefile +++ b/drivers/power/reset/Makefile @@ -41,3 +41,4 @@ obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o obj-$(CONFIG_POWER_RESET_SC27XX) += sc27xx-poweroff.o obj-$(CONFIG_NVMEM_REBOOT_MODE) += nvmem-reboot-mode.o obj-$(CONFIG_POWER_MLXBF) += pwr-mlxbf.o +obj-$(CONFIG_POWER_RESET_QEMU_VIRT_CTRL) += qemu-virt-ctrl.o diff --git a/drivers/power/reset/qemu-virt-ctrl.c b/drivers/power/reset/qemu-virt-ctrl.c new file mode 100644 index 000000000000..01409dfe2265 --- /dev/null +++ b/drivers/power/reset/qemu-virt-ctrl.c @@ -0,0 +1,122 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * QEMU Virt Machine System Controller Driver + * + * Copyright (C) 2026 Kuan-Wei Chiu <visitorckw@gmail.com> + */ + +#include <linux/io.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/reboot.h> + +/* Registers */ +#define VIRT_CTRL_REG_FEATURES 0x00 +#define VIRT_CTRL_REG_CMD 0x04 + +/* Commands */ +#define CMD_NOOP 0 +#define CMD_RESET 1 +#define CMD_HALT 2 +#define CMD_PANIC 3 + +struct qemu_virt_ctrl { + void __iomem *base; + struct notifier_block reboot_nb; +}; + +static inline void virt_ctrl_write32(u32 val, void __iomem *addr) +{ + if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) + iowrite32be(val, addr); + else + iowrite32(val, addr); +} + +static int qemu_virt_ctrl_power_off(struct sys_off_data *data) +{ + struct qemu_virt_ctrl *ctrl = data->cb_data; + + virt_ctrl_write32(CMD_HALT, ctrl->base + VIRT_CTRL_REG_CMD); + + return NOTIFY_DONE; +} + +static int qemu_virt_ctrl_restart(struct sys_off_data *data) +{ + struct qemu_virt_ctrl *ctrl = data->cb_data; + + virt_ctrl_write32(CMD_RESET, ctrl->base + VIRT_CTRL_REG_CMD); + + return NOTIFY_DONE; +} + +static int qemu_virt_ctrl_reboot_notify(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct qemu_virt_ctrl *ctrl = container_of(nb, struct qemu_virt_ctrl, reboot_nb); + + if (action == SYS_HALT) + virt_ctrl_write32(CMD_HALT, ctrl->base + VIRT_CTRL_REG_CMD); + + return NOTIFY_DONE; +} + +static int qemu_virt_ctrl_probe(struct platform_device *pdev) +{ + struct qemu_virt_ctrl *ctrl; + int ret; + + ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL); + if (!ctrl) + return -ENOMEM; + + ctrl->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(ctrl->base)) + return PTR_ERR(ctrl->base); + + ret = devm_register_sys_off_handler(&pdev->dev, + SYS_OFF_MODE_RESTART, + SYS_OFF_PRIO_DEFAULT, + qemu_virt_ctrl_restart, + ctrl); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "cannot register restart handler\n"); + + ret = devm_register_sys_off_handler(&pdev->dev, + SYS_OFF_MODE_POWER_OFF, + SYS_OFF_PRIO_DEFAULT, + qemu_virt_ctrl_power_off, + ctrl); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "cannot register power-off handler\n"); + + ctrl->reboot_nb.notifier_call = qemu_virt_ctrl_reboot_notify; + ret = devm_register_reboot_notifier(&pdev->dev, &ctrl->reboot_nb); + if (ret) + return dev_err_probe(&pdev->dev, ret, "cannot register reboot notifier\n"); + + return 0; +} + +static const struct platform_device_id qemu_virt_ctrl_id[] = { + { "qemu-virt-ctrl", 0 }, + { } +}; +MODULE_DEVICE_TABLE(platform, qemu_virt_ctrl_id); + +static struct platform_driver qemu_virt_ctrl_driver = { + .probe = qemu_virt_ctrl_probe, + .driver = { + .name = "qemu-virt-ctrl", + }, + .id_table = qemu_virt_ctrl_id, +}; +module_platform_driver(qemu_virt_ctrl_driver); + +MODULE_AUTHOR("Kuan-Wei Chiu <visitorckw@gmail.com>"); +MODULE_DESCRIPTION("QEMU Virt Machine System Controller Driver"); +MODULE_LICENSE("GPL"); |