From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-g122.zoho.com (sender4-pp-g122.zoho.com [136.143.188.122]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51B51274FEB; Fri, 30 Jan 2026 21:55:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.122 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769810126; cv=pass; b=sNRgDbjINlpeySfZBGEj+zYhWQEv2IJVv0z60yjWtWoUunJJ8fqo4v9xT+zq8UyO6BMOOxf1s2LRiIVpajca6xk/kx9ijHJt4Qd1U8xezPKybujm0irjjMsQn/+eA0YvZLY0ZcuWgV2UoHIHpo+2OTp6uhzogtMKfg54G2Ich5Y= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769810126; c=relaxed/simple; bh=f/ioZsDfsMv6gqZoKdcHXoE+WgqS/5R1QqEDb8CN4Jo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GKUz57svprUB7ADExgUYsSpv+Nf1PjnbaoA42IyTyXIEfHOvTB51sa0oYTeTCWAtV44WoM/Ci3a/OVNIGYb32jbEchaTmFOuN5/3DB5R92IyLnBZ6g6ecS3g9FpWsrrV1rOnaaHtHqhsJeYCk8nJylEuj66I20rN2bFsKgp1ohI= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=sebastian.reichel@collabora.com header.b=V54xX0yT; arc=pass smtp.client-ip=136.143.188.122 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=sebastian.reichel@collabora.com header.b="V54xX0yT" ARC-Seal: i=1; a=rsa-sha256; t=1769810110; cv=none; d=zohomail.com; s=zohoarc; b=m3/AihjscZDWWtbWW2DQr47E1F29oZx1IJHlx+z2pNZ7VaKHRPxLzYLbbVQeMPTr0dy1GbnOZzx1vCjbPd+MZobQgriZOuW0LhkuZHuSJwWuc4ix7IJNpZjNB9eskla/PV6+fIzSqcvXInaqpSFEDq4NmW+Ww1IkmKKREf+fsMw= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1769810110; h=Content-Type:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=aPD4oMdEco4XFgVOznBWvTfVRBU8KX3sxYf1g6Ve5yM=; b=Wp5FAdjWvv7e9vu/c6rRO78b/+yq61ceK2Yu7O9tJyy9ee6uJfh/rWajzeWRTplxfdhKDqZ7HgVUd3hd+4EswttnvBG29ZOiZ4kJ5RAINSVQkTW+monq31ZYzpsZS1YiCKZhv1MG7aI1UYHFjyBFMXp/YNy/EeQYDSEtQaqqLL0= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=sebastian.reichel@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1769810110; s=zohomail; d=collabora.com; i=sebastian.reichel@collabora.com; h=Date:Date:From:From:To:To:Cc:Cc:Subject:Subject:Message-ID:References:MIME-Version:Content-Type:In-Reply-To:Message-Id:Reply-To; bh=aPD4oMdEco4XFgVOznBWvTfVRBU8KX3sxYf1g6Ve5yM=; b=V54xX0yTlnvgCp7+42aAeArmv9qA55zo5ouvHpKTAhvVxJQAlb6USC60f5JGfFEO kgTdeXWv988uvmcusal6gbcBbI6wSOdVy+B4kL2hXY8sChJnwgIC8egB1KMf3XITMki +nnFb9hgddPLjDS3RqSlqLFnbUhMHSWHIOHlcXfw= Received: by mx.zohomail.com with SMTPS id 1769810107734190.12515268098207; Fri, 30 Jan 2026 13:55:07 -0800 (PST) Received: by venus (Postfix, from userid 1000) id BE68B18050E; Fri, 30 Jan 2026 22:55:00 +0100 (CET) Date: Fri, 30 Jan 2026 22:55:00 +0100 From: Sebastian Reichel To: Kuan-Wei Chiu Cc: geert@linux-m68k.org, jserv@ccns.ncku.edu.tw, eleanor15x@gmail.com, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-pm@vger.kernel.org Subject: Re: [PATCH 1/2] power: reset: Add QEMU virt-ctrl driver Message-ID: References: <20260112182258.1851769-1-visitorckw@gmail.com> <20260112182258.1851769-2-visitorckw@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="dxdfocqzfegfbwga" Content-Disposition: inline In-Reply-To: <20260112182258.1851769-2-visitorckw@gmail.com> X-Zoho-Virus-Status: 1 X-Zoho-AV-Stamp: zmail-av-0.2.1.1.4.3/269.789.21 X-ZohoMailClient: External --dxdfocqzfegfbwga Content-Type: text/plain; protected-headers=v1; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [PATCH 1/2] power: reset: Add QEMU virt-ctrl driver MIME-Version: 1.0 Hi, On Mon, Jan 12, 2026 at 06:22:56PM +0000, Kuan-Wei Chiu wrote: > 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]. >=20 > This driver registers a restart handler for system reboot and sets the > global pm_power_off callback for system shutdown. It is designed to be > generic and can be reused by other architectures utilizing this QEMU > device. >=20 > Link: https://gitlab.com/qemu-project/qemu/-/blob/v10.2.0/hw/misc/virt_ct= rl.c [1] > Signed-off-by: Kuan-Wei Chiu > --- > MAINTAINERS | 6 ++ > drivers/power/reset/Kconfig | 10 +++ > drivers/power/reset/Makefile | 1 + > drivers/power/reset/qemu-virt-ctrl.c | 98 ++++++++++++++++++++++++++++ > 4 files changed, 115 insertions(+) > create mode 100644 drivers/power/reset/qemu-virt-ctrl.c >=20 > diff --git a/MAINTAINERS b/MAINTAINERS > index 0d044a58cbfe..2586e4162304 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -21179,6 +21179,12 @@ 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..1ca1c2913cbc 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 Bl= ueField. > =20 > +config POWER_RESET_QEMU_VIRT_CTRL > + bool "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-$(CONFIG_SYSCON_REBOOT_MODE) +=3D syscon-reboot-mod= e.o > obj-$(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/q= emu-virt-ctrl.c > new file mode 100644 > index 000000000000..f1acd22172ce > --- /dev/null > +++ b/drivers/power/reset/qemu-virt-ctrl.c > @@ -0,0 +1,98 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * QEMU Virt Machine System Controller Driver > + * > + * Copyright (C) 2026 Kuan-Wei Chiu > + */ > + > +#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 restart_nb; > +}; > + > +static void __iomem *qemu_virt_ctrl_base; > + > +static void qemu_virt_ctrl_power_off(void) > +{ > + if (qemu_virt_ctrl_base) > + iowrite32be(CMD_HALT, qemu_virt_ctrl_base + VIRT_CTRL_REG_CMD); > +} > + > +static int qemu_virt_ctrl_restart(struct notifier_block *nb, unsigned lo= ng action, > + void *data) > +{ > + struct qemu_virt_ctrl *vc =3D container_of(nb, struct qemu_virt_ctrl, r= estart_nb); > + > + iowrite32be(CMD_RESET, vc->base + VIRT_CTRL_REG_CMD); > + > + return NOTIFY_DONE; > +} > + > +static int qemu_virt_ctrl_probe(struct platform_device *pdev) > +{ > + struct qemu_virt_ctrl *vc; > + int ret; > + > + vc =3D devm_kzalloc(&pdev->dev, sizeof(*vc), GFP_KERNEL); > + if (!vc) > + return -ENOMEM; > + > + vc->base =3D devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(vc->base)) > + return PTR_ERR(vc->base); > + > + qemu_virt_ctrl_base =3D vc->base; > + > + vc->restart_nb.notifier_call =3D qemu_virt_ctrl_restart; > + vc->restart_nb.priority =3D 128; > + > + ret =3D register_restart_handler(&vc->restart_nb); > + if (ret) > + return dev_err_probe(&pdev->dev, ret, > + "cannot register restart handler\n"); Please use devm_register_sys_off_handler(). > + if (!pm_power_off) > + pm_power_off =3D qemu_virt_ctrl_power_off; same. > + platform_set_drvdata(pdev, vc); > + > + return 0; > +} > + > +static void qemu_virt_ctrl_remove(struct platform_device *pdev) > +{ > + struct qemu_virt_ctrl *vc =3D platform_get_drvdata(pdev); > + > + unregister_restart_handler(&vc->restart_nb); > + > + if (pm_power_off =3D=3D qemu_virt_ctrl_power_off) > + pm_power_off =3D NULL; > +} > + > +static struct platform_driver qemu_virt_ctrl_driver =3D { > + .probe =3D qemu_virt_ctrl_probe, > + .remove =3D qemu_virt_ctrl_remove, > + .driver =3D { > + .name =3D "qemu-virt-ctrl", > + }, > +}; > +module_platform_driver(qemu_virt_ctrl_driver); > + > +MODULE_AUTHOR("Kuan-Wei Chiu "); > +MODULE_DESCRIPTION("QEMU Virt Machine System Controller Driver"); > +MODULE_LICENSE("GPL"); You mark this as module_platform_driver() and add MODULE_*, but the Kconfig option is bool. To be usable as a module it is missing setup of .id_table in the platform_driver struct for auto-loading. Greetings, -- Sebastian --dxdfocqzfegfbwga Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE72YNB0Y/i3JqeVQT2O7X88g7+poFAml9KLEACgkQ2O7X88g7 +pqFhw/9EqvDetKzSO5FMxKDgybRNnz69sGBWYuh7L2geGJp2uzYf9jbmU7eDV13 xR/PGOCyIhPI2FSLfT0TZAq/yEavFUxCDTBg4bdt4w1t3FOSpmRVR2hC1eVZWjVx Bpo6rggkVC32DCc0yXBFTqRuTPNj6hiV2healG8MZrvjkbIjA3p59yk6SgNybIIb zt4czYVuP3wzY+PMqO5ayKFT8UHqZsSvfit8lNEWew+6VYkQZh15S/VHwVw6yPPF dn27TipdYNyJEAttfwkX9/4hqcxqpAMM8yjBIONZ6VHbcpI7N0zqWs1gxgq9hUyl uHRmzh+F9NhWhouE8PYLFqksct8NPUBTEmMjdUpIkMVilP1d5mkXMWL3v6mS9q4z b7y1GVDDglpxafYcPhiJcQ1dLPWNnznWdk4uHKLYDUGj2qoazNSi23omI33hUqGI HBTdhr/IMA2Imo6+3S5gmnMtZIVn90pyNDAzDFIWTBindXF2/aA2Dhmt/6e4vJY8 xW9nfcUWJ18tlnYoQZnysy0CLLnlXTdNCFdQbNma9pp/lQ/WKr11rIvnQps6vrE+ 6MeF/Bxd4n/Jq7c9nnYxcQWYpva/ydRomufN+Y05ghd3zI1Ag954VnKnCmd9OnyL 8Fst+zelxUPFl2lc5AFFcZjcKMzRnJ58NO/tjfVeCMzxxRLdKQk= =7oqZ -----END PGP SIGNATURE----- --dxdfocqzfegfbwga--