Re: [PATCH v23 07/13] power: reset: Add psci-reboot-mode driver

[Pavan Kondeti]

On Tue, Jul 14, 2026 at 10:46:35PM +0530, Shivendra Pratap wrote:
> 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@xxxxxxxxxxxxxxxx>
> ---
>  MAINTAINERS                            |  1 +
>  drivers/power/reset/Kconfig            | 10 +++++
>  drivers/power/reset/Makefile           |  1 +
>  drivers/power/reset/psci-reboot-mode.c | 78 ++++++++++++++++++++++++++++++++++
>  4 files changed, 90 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e1ed6abef62a..4910abafa170 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -21576,6 +21576,7 @@ 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 124afb99febe..93e4029d9506 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 || COMPILE_TEST)
> +	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.
> +

Since we have added predefined-resets support, why are we forcing this
driver to depend on OF?

For example, `reboot psci-system-reset2-arch-warm-reset` gives me
warm reset on non-DT systems, correct?

>  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 d7ae97241a83..02948622fe3d 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 000000000000..955ed68f1402
> --- /dev/null
> +++ b/drivers/power/reset/psci-reboot-mode.c
> @@ -0,0 +1,78 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <linux/array_size.h>
> +#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>
> +
> +static const struct reboot_mode_entry psci_resets[] = {
> +	{
> +		.name  = "psci-system-reset",
> +		.magic = { 0, PSCI_SYSTEM_RESET_COLD_RESET },
> +		.count = 2,
> +	},
> +	{
> +		.name  = "psci-system-reset2-arch-warm-reset",
> +		.magic = { 0, PSCI_SYSTEM_RESET2_ARCH_WARM_RESET },
> +		.count = 2,
> +	},
> +};
> +

Thanks,
Pavan