From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f47.google.com (mail-pj1-f47.google.com [209.85.216.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DD1603822BB for ; Sun, 12 Apr 2026 21:20:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776028814; cv=none; b=DW9FesRlt4EbkDawMGttHeaUV8NH/x5yPbpAi0APz1AaWdv13HE96KhCjYE74GZXUYLtr89w8Sv9drM19H+Hcm+UN2SL68TiLyVPtoP1HU//9QsVAcVM+MQQRWMHIUmNIFWN9LFzH38B2rRsYS2/sKEXybH1Q08+8xuKazU9+Jk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776028814; c=relaxed/simple; bh=k8VI7MRV0RzMVUJwg6fgfku3HWrwyDhLnGC8Egha3XI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O0W+OLc8rwd0seEwjtE73Vr1Vb7BxTm9E8a5qTRSimDfjiaPUKlaI37w4AL746wNZ2vzYQ3nOWZIAvzbqHRXy3IBs7JinUowTBSsAxfAVlrNBq71EItlCutnU1Uo24vkObIFn2Rkzm9X2OdV1OU2WtBV51UcXCwRJNvhRvr53tU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=d2/GcBSE; arc=none smtp.client-ip=209.85.216.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="d2/GcBSE" Received: by mail-pj1-f47.google.com with SMTP id 98e67ed59e1d1-35e563b0ee7so341786a91.1 for ; Sun, 12 Apr 2026 14:20:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776028812; x=1776633612; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Hv96ERjBO9/NiOyiLL/BGaUYHQpO00Dknp/iQI1oqNE=; b=d2/GcBSEhRbh7rF7/1faAYhb36OFpCmd8TEURxjXDGtFRcuvzuRKiKbqfHe7evKPdX v6OYmv4oAddGGOWBbhgrIGkyspz/T54IHLrIW4j1VquoD8Y3nAHbalEELPyD393wf1as KqcAlkJZtGGsCdhajEEtvAJE5KE/eyO+LttzxqO4fl0P2f7SYLdoDSMseQgBV1zGamdx uCs7BVK6ksb2w29XTON6/kiYAsb5TcTnz5RgNx0YgLWTxWcaCADoJWi2unDk3eoGMrAe 4I4BWDI5WH0djiJdbYQWaO0UxBnj6jtFEoI6bpbEyl9wEPyjZ5xCky+idHgrWEpNB+Xo OxcA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776028812; x=1776633612; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=Hv96ERjBO9/NiOyiLL/BGaUYHQpO00Dknp/iQI1oqNE=; b=jyqn11fUgc8BIYzf/GTt/a1NQL7rEiD2BN+K8IzaWMfnqsuKscQCM4XrJC6WAK9TBo 5Ab9O9GlWLNqcyEO6U1gtSyFRmyDpWOrOnJD2nggSPXMde+5Viky9dpzAhmtlSPNuEdX qILiDfQnUykamtsEn0UKYoIqedgaXE+g6tfn1147n4onEDK4hpToFvJ0nU3tPLPW8M1n PfIlm5wiEkrsPps5BJSds9Lg4zD6IIvzBCl84RrnhLn7B+8GJ+6qHu/Sprz9awBPdMsx UTjo3dFcPh5b7o3QrUPwTD/0KHVhQ58xAfHXlhZTNiGYRgCSfYx2tLWHpT+rWOCRCbtD CNyQ== X-Forwarded-Encrypted: i=1; AFNElJ9UHEeJWgvHHoyqK1a2Dl/RO9FfyOmUPkkghAWNzgfBL/XOkAERt4+gi5gXqvi2G5n8IhegKNXqHQ==@vger.kernel.org X-Gm-Message-State: AOJu0Yy36YG/AD2/xoPfay9SnVjS+HPhOV4AshKhT1Lfe+m8nTP6qw9v o4hkRO0QJf2TCJrfllQBDcwORme7h36Nbd/juH9Cu7+wJ2eT7vEhIuXD X-Gm-Gg: AeBDietTnf9ZSo26PImuRSm6EnQRD5AXvIBK2sc6G/zwZwTlcn5+fYZ7UpeMJsvWWoB z+8CCTdGVQt8LM392+It1HOJgN4FYjoGL1W/5xdwxfKCgf2PaiQOk0zQsIE/OPqDTiFoo7HLVaO rmWDXKjs+iMLt1bMixPM3JbIMrqx09GOVAvLTta1rFj9U6OE86Pg4Nti+yFFxi3gopCMUSkFopg DTYGLwuPlfUUl4w8sevY11GSU7cRRSPezZouGh/7/i32ZEbspIg+MhpKxqUK4Jn/2o0RtD1EVdd oc00pfhwNgcih48VkVt91uoAqh54ySMit2Vn3EJ5315K/yVXXtDsQiMterxl6kZan5p9oBnKNZf pwo5Q7dnlPpGSucl3tDmR0XTZckPxyD/4Y3OuEKl8kxxje2S8IZUp5oZIAjvu6QOtnxN4oBAKUZ nPoUz8thBEZA/paapYc6l1UoH/QvlHQnMyvP9GLW8D5MIqtwEKw1KOBTNa1eeSVHB73It86dryN LTV/okiV+eYlOFjaif5g2Go07wDNDJpvcwvL28= X-Received: by 2002:a17:90b:164d:b0:35a:2ed:9b6f with SMTP id 98e67ed59e1d1-35e351f6d14mr14899912a91.0.1776028812173; Sun, 12 Apr 2026 14:20:12 -0700 (PDT) Received: from visitorckw-work01.c.googlers.com.com (100.130.194.35.bc.googleusercontent.com. [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-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 +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 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 + */ + +#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 = 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 "); +MODULE_DESCRIPTION("QEMU Virt Machine System Controller Driver"); +MODULE_LICENSE("GPL"); -- 2.53.0.1213.gd9a14994de-goog