Re: [PATCH v25 06/10] power: reset: Add psci-reboot-mode driver

[Bartosz Golaszewski]

On Mon, 14 Sep 2026 16:59:10 +0200, Shivendra Pratap
<shivendra.pratap@xxxxxxxxxxxxxxxx> said:
> PSCI supports different types of resets like SYSTEM_RESET, SYSTEM_RESET2
> ARCH WARM reset and SYSTEM_RESET2 vendor-specific resets. Currently
> there is no common driver that handles all supported psci resets at one
> place. Additionally, there is no common mechanism to issue the supported
> psci resets from userspace.
>
> Add psci-reboot-mode as an auxiliary device created by the psci-devices
> driver. Define two types of PSCI resets, predefined-resets and
> vendor-specific resets.  Predefined-resets are defined by psci driver
> and vendor-specific resets are defined by SoC vendors, under the
> psci:reboot-mode node of SoC device tree.
>
> Register the driver with the reboot-mode framework to interface these
> resets to userspace. When userspace initiates a supported command, pass
> the reset arguments to the PSCI driver to enable command-based reset.
>
> This change allows userspace to issue supported PSCI reset commands
> using the standard reboot system calls while enabling SoC vendors to
> define their specific resets for PSCI.
>
> Suggested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxxxx>
> Suggested-by: Lee Jones <lee@xxxxxxxxxx>
> Suggested-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
> Signed-off-by: Shivendra Pratap <shivendra.pratap@xxxxxxxxxxxxxxxx>
> ---
>  MAINTAINERS                            |   1 +
>  drivers/firmware/psci/psci-devices.c   |  71 +++++++++++++++++++++-
>  drivers/power/reset/Kconfig            |  10 ++++
>  drivers/power/reset/Makefile           |   1 +
>  drivers/power/reset/psci-reboot-mode.c | 104 +++++++++++++++++++++++++++++++++
>  5 files changed, 185 insertions(+), 2 deletions(-)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 9c0334ee2ed2..1c0f111ba197 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21933,6 +21933,7 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/arm/psci.yaml
>  F:	drivers/firmware/psci/
>  F:	drivers/firmware/psci/psci-devices.c
> +F:	drivers/power/reset/psci-reboot-mode.c
>  F:	include/linux/psci.h
>  F:	include/uapi/linux/psci.h
>
> diff --git a/drivers/firmware/psci/psci-devices.c b/drivers/firmware/psci/psci-devices.c
> index f1eca61e3269..43e6743202f9 100644
> --- a/drivers/firmware/psci/psci-devices.c
> +++ b/drivers/firmware/psci/psci-devices.c
> @@ -4,19 +4,86 @@
>   */
>
>  #include <linux/auxiliary_bus.h>
> +#include <linux/device.h>
>  #include <linux/init.h>
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
> +#include <linux/psci.h>
> +#include <linux/slab.h>
> +
> +static void arm_psci_auxiliary_device_release(struct device *dev)
> +{
> +	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
> +
> +	of_node_put(dev->of_node);
> +	kfree(auxdev);
> +}
> +
> +static struct auxiliary_device *
> +arm_psci_auxiliary_device_create(struct device *dev, const char *devname,
> +				 struct device_node *np)
> +{
> +	struct auxiliary_device *auxdev;
> +	int ret;
> +
> +	auxdev = kzalloc_obj(*auxdev);
> +	if (!auxdev)
> +		return NULL;
> +
> +	auxdev->id = 0;
> +	auxdev->name = devname;
> +	auxdev->dev.parent = dev;
> +	auxdev->dev.release = arm_psci_auxiliary_device_release;
> +
> +	if (np)
> +		device_set_node(&auxdev->dev, of_fwnode_handle(of_node_get(np)));
> +
> +	ret = auxiliary_device_init(auxdev);
> +	if (ret) {
> +		of_node_put(auxdev->dev.of_node);
> +		kfree(auxdev);
> +		return NULL;
> +	}
> +
> +	ret = __auxiliary_device_add(auxdev, "arm-psci");
> +	if (ret) {
> +		auxiliary_device_uninit(auxdev);
> +		return NULL;
> +	}
> +
> +	ret = devm_add_action_or_reset(dev, auxiliary_device_destroy, auxdev);
> +	if (ret)
> +		return NULL;
> +
> +	return auxdev;
> +}
>
>  static int arm_psci_probe(struct platform_device *pdev)
>  {
>  	struct auxiliary_device *auxdev;
> +#ifdef CONFIG_PSCI_REBOOT_MODE
> +	struct device_node *reboot_mode_np = NULL;
> +#endif
>
> -	auxdev = __devm_auxiliary_device_create(&pdev->dev, "arm-psci",
> -						"psci-cpuidle-domain", NULL, 0);
> +	auxdev = arm_psci_auxiliary_device_create(&pdev->dev,
> +						  "psci-cpuidle-domain",
> +						  pdev->dev.of_node);
>  	if (!auxdev)
>  		return -ENOMEM;
>
> +#ifdef CONFIG_PSCI_REBOOT_MODE
> +	if (psci_has_system_reset2_support())
> +		reboot_mode_np = of_get_child_by_name(pdev->dev.of_node,
> +						      "reboot-mode");
> +
> +	auxdev = arm_psci_auxiliary_device_create(&pdev->dev,
> +						  "psci-reboot-mode",
> +						  reboot_mode_np);
> +	of_node_put(reboot_mode_np);
> +	if (!auxdev)
> +		dev_warn(&pdev->dev, "failed to create PSCI reboot mode device\n");
> +#endif
> +
>  	return 0;
>  }
>
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index bce996bbef28..5c349f41e097 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -360,6 +360,16 @@ config NVMEM_REBOOT_MODE
>  	  then the bootloader can read it and take different
>  	  action according to the mode.
>
> +config PSCI_REBOOT_MODE
> +	bool "PSCI reboot mode driver"
> +	depends on ARM_PSCI_DEVICES
> +	select REBOOT_MODE

Needs: select AUXILIARY_BUS

> +	help
> +	  Say y here to enable the PSCI reboot mode driver. The driver
> +	  registers with the reboot-mode framework to configure PSCI
> +	  reset commands, which are executed by the PSCI driver during
> +	  psci_sys_reset().
> +
>  config POWER_MLXBF
>  	tristate "Mellanox BlueField power handling driver"
>  	depends on (GPIO_MLXBF2 || GPIO_MLXBF3) && ACPI
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index e31cab4ba78e..45d8aaaffaa1 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -41,5 +41,6 @@ obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o
>  obj-$(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-$(CONFIG_PSCI_REBOOT_MODE) += psci-reboot-mode.o
>  obj-$(CONFIG_POWER_MLXBF) += pwr-mlxbf.o
>  obj-$(CONFIG_POWER_RESET_QEMU_VIRT_CTRL) += qemu-virt-ctrl.o
> diff --git a/drivers/power/reset/psci-reboot-mode.c b/drivers/power/reset/psci-reboot-mode.c
> new file mode 100644
> index 000000000000..bf2dd6626feb
> --- /dev/null
> +++ b/drivers/power/reset/psci-reboot-mode.c
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <linux/array_size.h>
> +#include <linux/auxiliary_bus.h>
> +#include <linux/device.h>

[

> +#include <linux/errno.h>
> +#include <linux/init.h>
> +#include <linux/kconfig.h>

]

Why are you including these?

Bart