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[35.194.130.100]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c7921a3e6d2sm7615779a12.32.2026.04.12.14.20.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Apr 2026 14:20:11 -0700 (PDT) From: Kuan-Wei Chiu To: geert@linux-m68k.org, sre@kernel.org Cc: jserv@ccns.ncku.edu.tw, eleanor15x@gmail.com, daniel@0x0f.com, laurent@vivier.eu, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-pm@vger.kernel.org, Kuan-Wei Chiu , Sebastian Reichel Subject: [PATCH v4 1/2] power: reset: Add QEMU virt-ctrl driver Date: Sun, 12 Apr 2026 21:19:51 +0000 Message-ID: <20260412211952.3564033-2-visitorckw@gmail.com> X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog In-Reply-To: <20260412211952.3564033-1-visitorckw@gmail.com> References: <20260412211952.3564033-1-visitorckw@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add a new driver for the 'virt-ctrl' device found on QEMU virt machines (e.g. m68k). This device provides a simple interface for system reset and power off [1]. This driver utilizes the modern system-off API to register callbacks for both system restart and power off. It also registers a reboot notifier to catch SYS_HALT events, ensuring that LINUX_REBOOT_CMD_HALT is properly handled. It is designed to be generic and can be reused by other architectures utilizing this QEMU device. Link: https://gitlab.com/qemu-project/qemu/-/blob/v10.2.0/hw/misc/virt_ctrl= .c [1] Signed-off-by: Kuan-Wei Chiu Acked-by: Sebastian Reichel --- Changes in v4: - Fix sparse warning caught by kernel test robot. - Pass the struct qemu_virt_ctrl context to sys-off handlers instead of the __iomem pointer. MAINTAINERS | 6 ++ drivers/power/reset/Kconfig | 10 +++ drivers/power/reset/Makefile | 1 + drivers/power/reset/qemu-virt-ctrl.c | 122 +++++++++++++++++++++++++++ 4 files changed, 139 insertions(+) create mode 100644 drivers/power/reset/qemu-virt-ctrl.c diff --git a/MAINTAINERS b/MAINTAINERS index 55af015174a5..aa9eb8540637 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -21441,6 +21441,12 @@ S: Maintained F: drivers/firmware/qemu_fw_cfg.c F: include/uapi/linux/qemu_fw_cfg.h =20 +QEMU VIRT MACHINE SYSTEM CONTROLLER DRIVER +M: Kuan-Wei Chiu +L: linux-pm@vger.kernel.org +S: Maintained +F: drivers/power/reset/qemu-virt-ctrl.c + QLOGIC QL41xxx FCOE DRIVER M: Saurav Kashyap M: Javed Hasan 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 Blue= Field. =20 +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-$(CONFIG_SYSCON_REBOOT_MODE) +=3D syscon-reboot-mode.o obj-$(CONFIG_POWER_RESET_SC27XX) +=3D sc27xx-poweroff.o obj-$(CONFIG_NVMEM_REBOOT_MODE) +=3D nvmem-reboot-mode.o obj-$(CONFIG_POWER_MLXBF) +=3D pwr-mlxbf.o +obj-$(CONFIG_POWER_RESET_QEMU_VIRT_CTRL) +=3D qemu-virt-ctrl.o diff --git a/drivers/power/reset/qemu-virt-ctrl.c b/drivers/power/reset/qem= u-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 + */ + +#include +#include +#include +#include +#include + +/* 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 =3D 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 =3D 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 =3D container_of(nb, struct qemu_virt_ctrl, r= eboot_nb); + + if (action =3D=3D 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 =3D devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL); + if (!ctrl) + return -ENOMEM; + + ctrl->base =3D devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(ctrl->base)) + return PTR_ERR(ctrl->base); + + ret =3D 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 =3D 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 =3D qemu_virt_ctrl_reboot_notify; + ret =3D 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[] =3D { + { "qemu-virt-ctrl", 0 }, + { } +}; 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[35.194.130.100]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c7921a3e6d2sm7615779a12.32.2026.04.12.14.20.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Apr 2026 14:20:15 -0700 (PDT) From: Kuan-Wei Chiu To: geert@linux-m68k.org, sre@kernel.org Cc: jserv@ccns.ncku.edu.tw, eleanor15x@gmail.com, daniel@0x0f.com, laurent@vivier.eu, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-pm@vger.kernel.org, Kuan-Wei Chiu Subject: [PATCH v4 2/2] m68k: virt: Switch to qemu-virt-ctrl driver Date: Sun, 12 Apr 2026 21:19:52 +0000 Message-ID: <20260412211952.3564033-3-visitorckw@gmail.com> X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog In-Reply-To: <20260412211952.3564033-1-visitorckw@gmail.com> References: <20260412211952.3564033-1-visitorckw@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Register the "qemu-virt-ctrl" platform device during board initialization to utilize the new generic power/reset driver. Consequently, remove the legacy reset and power-off implementations specific to the virt machine. The platform's mach_reset callback is updated to call do_kernel_restart(), bridging the legacy m68k reboot path to the generic kernel restart handler framework for this machine. To prevent any regressions in reboot or power-off functionality when the driver is not built-in, explicitly select POWER_RESET and POWER_RESET_QEMU_VIRT_CTRL for the VIRT machine in Kconfig.machine. Signed-off-by: Kuan-Wei Chiu Reviewed-by: Geert Uytterhoeven --- arch/m68k/Kconfig.machine | 2 ++ arch/m68k/virt/config.c | 42 +-------------------------------------- arch/m68k/virt/platform.c | 20 ++++++++++++++++--- 3 files changed, 20 insertions(+), 44 deletions(-) diff --git a/arch/m68k/Kconfig.machine b/arch/m68k/Kconfig.machine index de39f23b180e..624e6b27f394 100644 --- a/arch/m68k/Kconfig.machine +++ b/arch/m68k/Kconfig.machine @@ -133,6 +133,8 @@ config VIRT select GOLDFISH_TIMER select GOLDFISH_TTY select M68040 + select POWER_RESET + select POWER_RESET_QEMU_VIRT_CTRL select RTC_CLASS select RTC_DRV_GOLDFISH select TTY diff --git a/arch/m68k/virt/config.c b/arch/m68k/virt/config.c index 632ba200ad42..b338e2a8da6a 100644 --- a/arch/m68k/virt/config.c +++ b/arch/m68k/virt/config.c @@ -13,18 +13,6 @@ =20 struct virt_booter_data virt_bi_data; =20 -#define VIRT_CTRL_REG_FEATURES 0x00 -#define VIRT_CTRL_REG_CMD 0x04 - -static struct resource ctrlres; - -enum { - CMD_NOOP, - CMD_RESET, - CMD_HALT, - CMD_PANIC, -}; - static void virt_get_model(char *str) { /* str is 80 characters long */ @@ -33,25 +21,9 @@ static void virt_get_model(char *str) (u8)(virt_bi_data.qemu_version >> 16), (u8)(virt_bi_data.qemu_version >> 8)); } - -static void virt_halt(void) -{ - void __iomem *base =3D (void __iomem *)virt_bi_data.ctrl.mmio; - - iowrite32be(CMD_HALT, base + VIRT_CTRL_REG_CMD); - local_irq_disable(); - while (1) - ; -} - static void virt_reset(void) { - void __iomem *base =3D (void __iomem *)virt_bi_data.ctrl.mmio; - - iowrite32be(CMD_RESET, base + VIRT_CTRL_REG_CMD); - local_irq_disable(); - while (1) - ; + do_kernel_restart(NULL); } =20 /* @@ -113,20 +85,8 @@ void __init config_virt(void) virt_bi_data.tty.mmio); setup_earlycon(earlycon); =20 - ctrlres =3D (struct resource) - DEFINE_RES_MEM_NAMED(virt_bi_data.ctrl.mmio, 0x100, - "virtctrl"); - - if (request_resource(&iomem_resource, &ctrlres)) { - pr_err("Cannot allocate virt controller resource\n"); - return; - } - mach_init_IRQ =3D virt_init_IRQ; mach_sched_init =3D virt_sched_init; mach_get_model =3D virt_get_model; mach_reset =3D virt_reset; - mach_halt =3D virt_halt; - - register_platform_power_off(virt_halt); } diff --git a/arch/m68k/virt/platform.c b/arch/m68k/virt/platform.c index 1560c4140ab9..764f556b4b32 100644 --- a/arch/m68k/virt/platform.c +++ b/arch/m68k/virt/platform.c @@ -30,7 +30,10 @@ static int __init virt_platform_init(void) DEFINE_RES_MEM(virt_bi_data.rtc.mmio + 0x1000, 0x1000), DEFINE_RES_IRQ(virt_bi_data.rtc.irq + 1), }; - struct platform_device *pdev1, *pdev2; + const struct resource virt_ctrl_res[] =3D { + DEFINE_RES_MEM(virt_bi_data.ctrl.mmio, 0x100), + }; + struct platform_device *pdev1, *pdev2, *pdev3; struct platform_device *pdevs[VIRTIO_BUS_NB]; unsigned int i; int ret =3D 0; @@ -57,19 +60,30 @@ static int __init virt_platform_init(void) goto err_unregister_tty; } =20 + pdev3 =3D platform_device_register_simple("qemu-virt-ctrl", + PLATFORM_DEVID_NONE, + virt_ctrl_res, + ARRAY_SIZE(virt_ctrl_res)); + if (IS_ERR(pdev3)) { + ret =3D PTR_ERR(pdev3); + goto err_unregister_rtc; + } + for (i =3D 0; i < VIRTIO_BUS_NB; i++) { pdevs[i] =3D virt_virtio_init(i); if (IS_ERR(pdevs[i])) { ret =3D PTR_ERR(pdevs[i]); - goto err_unregister_rtc_virtio; + goto err_unregister_virtio; } } =20 return 0; =20 -err_unregister_rtc_virtio: +err_unregister_virtio: while (i > 0) platform_device_unregister(pdevs[--i]); + platform_device_unregister(pdev3); +err_unregister_rtc: platform_device_unregister(pdev2); err_unregister_tty: platform_device_unregister(pdev1); --=20 2.53.0.1213.gd9a14994de-goog