[PATCH] cpuidle: add riscv cpuidle driver

[Daniel Lezcano]

On 14/09/2020 03:52, liush wrote:
> This patch adds a cpuidle driver for systems based RISCV architecture.
> This patch supports state WFI. Other states will be supported in the
> future.
> 
> Signed-off-by: liush <liush at allwinnertech.com>
> ---

[ ... ]

>  
>  obj-$(CONFIG_RISCV_M_MODE)	+= traps_misaligned.o
> diff --git a/arch/riscv/kernel/cpuidle.c b/arch/riscv/kernel/cpuidle.c
> new file mode 100644
> index 00000000..a3289e7
> --- /dev/null
> +++ b/arch/riscv/kernel/cpuidle.c
> @@ -0,0 +1,8 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <asm/cpuidle.h>
> +
> +void cpu_do_idle(void)
> +{
> +	__asm__ __volatile__ ("wfi");
> +

extra line

> +}

As for the next deeper states should end up with the cpu_do_idle
function, isn't there an extra operation with the wfi() like flushing
the l1 cache?

> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
> index c0aeedd..f6be0fd 100644
> --- a/drivers/cpuidle/Kconfig
> +++ b/drivers/cpuidle/Kconfig
> @@ -62,6 +62,11 @@ depends on PPC
>  source "drivers/cpuidle/Kconfig.powerpc"
>  endmenu
>  
> +menu "RISCV CPU Idle Drivers"
> +depends on RISCV
> +source "drivers/cpuidle/Kconfig.riscv"
> +endmenu
> +
>  config HALTPOLL_CPUIDLE
>  	tristate "Halt poll cpuidle driver"
>  	depends on X86 && KVM_GUEST
> diff --git a/drivers/cpuidle/Kconfig.riscv b/drivers/cpuidle/Kconfig.riscv
> new file mode 100644
> index 00000000..e86d36b
> --- /dev/null
> +++ b/drivers/cpuidle/Kconfig.riscv
> @@ -0,0 +1,11 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +#
> +# RISCV CPU Idle drivers
> +#
> +config RISCV_CPUIDLE
> +        bool "Generic RISCV CPU idle Driver"
> +        select DT_IDLE_STATES
> +	select CPU_IDLE_MULTIPLE_DRIVERS
> +        help
> +          Select this option to enable generic cpuidle driver for RISCV.
> +	  Now only support C0 State.

Identation

Rest looks ok for me.


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