[PATCH v22 07/13] power: reset: Add psci-reboot-mode driver

[Bartosz Golaszewski]

On Thu, 14 May 2026 16:25:48 +0200, Shivendra Pratap
<shivendra.pratap at oss.qualcomm.com> 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 a psci-reboot-mode driver, and 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.
>
> Signed-off-by: Shivendra Pratap <shivendra.pratap at oss.qualcomm.com>
> ---
>  MAINTAINERS                            |  1 +
>  drivers/power/reset/Kconfig            | 10 +++++
>  drivers/power/reset/Makefile           |  1 +
>  drivers/power/reset/psci-reboot-mode.c | 72 ++++++++++++++++++++++++++++++++++
>  4 files changed, 84 insertions(+)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 36ba42209c0b332813a296880cd55798a5592d2a..4b0815c31679550f5ab719de4a5852990c7cc643 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21342,6 +21342,7 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/arm/psci.yaml
>  F:	drivers/firmware/psci/
>  F:	drivers/mfd/psci-mfd.c
> +F:	drivers/power/reset/psci-reboot-mode.c
>  F:	include/linux/psci.h
>  F:	include/uapi/linux/psci.h
>
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index 124afb99febe92450b6ae322aeed3b63fa2070df..d9d1f768b8691abc3b32f2675519f2ddbaf19b84 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -348,6 +348,16 @@ 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 OF && ARM_PSCI_FW

Can you add COMPILE_TEST coverage here too please?

> +	select REBOOT_MODE
> +	help
> +	  Say y here will enable PSCI reboot mode driver. This gets
> +	  the PSCI reboot mode arguments and passes them to psci
> +	  driver. psci driver uses these arguments for issuing
> +	  device reset into different boot states.
> +
>  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 d7ae97241a838fe1b536b2f911868e7590d12e3b..02948622fe3d00e165f941108ab92ecb66b0f0e8 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -40,5 +40,6 @@ 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 0000000000000000000000000000000000000000..845b2a1816ce53451dea8dfc4bffffda0d3e9293
> --- /dev/null
> +++ b/drivers/power/reset/psci-reboot-mode.c
> @@ -0,0 +1,72 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/psci.h>
> +#include <linux/reboot-mode.h>
> +#include <linux/types.h>
> +
> +/*
> + * Predefined modes:
> + *   reset_type = 0
> + *   cookie stored in magic[63:32]
> + */
> +#define PSCI_PREDEF_MAGIC(cookie)	((cookie) * BIT_ULL(32))
> +
> +static const struct reboot_mode_entry psci_resets[] = {
> +	{
> +		.name  = "psci-system-reset",
> +		.magic = PSCI_PREDEF_MAGIC(PSCI_RESET_TYPE_SYSTEM_RESET),
> +	},
> +	{
> +		.name  = "psci-system-reset2-arch-warm-reset",
> +		.magic = PSCI_PREDEF_MAGIC(PSCI_RESET_TYPE_SYSTEM_RESET2_ARCH_WARM),
> +	},
> +};
> +
> +/*
> + * magic is a pre-encoded value:
> + *   reset_type in low 32 bits
> + *   cookie in high 32 bits
> + */
> +static int psci_reboot_mode_write(struct reboot_mode_driver *reboot, u64 magic)
> +{
> +	psci_set_reset_cmd(magic);
> +	return 0;
> +}
> +
> +static int psci_reboot_mode_probe(struct platform_device *pdev)
> +{
> +	struct reboot_mode_driver *reboot;
> +	size_t count;
> +	int ret;
> +
> +	reboot = devm_kzalloc(&pdev->dev, sizeof(*reboot), GFP_KERNEL);
> +	if (!reboot)
> +		return -ENOMEM;
> +
> +	reboot_mode_driver_init(reboot, &pdev->dev, psci_reboot_mode_write);
> +
> +	/* Skip PSCI SYSTEM_RESET2 modes if unsupported */
> +	count = psci_has_system_reset2_support() ? ARRAY_SIZE(psci_resets) : 1;
> +	ret = reboot_mode_add_predefined_modes(reboot, psci_resets, count);
> +	if (ret)
> +		return ret;
> +
> +	return devm_reboot_mode_register(&pdev->dev, reboot);
> +}
> +
> +static struct platform_driver psci_reboot_mode_driver = {
> +	.probe  = psci_reboot_mode_probe,
> +	.driver = {
> +		.name	= "psci-reboot-mode",
> +	},
> +};
> +

You can drop the newline here.

> +module_platform_driver(psci_reboot_mode_driver);
> +
> +MODULE_LICENSE("GPL");
>
> --
> 2.34.1
>
>

With that:

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski at oss.qualcomm.com>