Re: [PATCH 03/20] ARM64 / ACPI: Introduce the skeleton of _PDC related for ARM64

[Sudeep Holla <Sudeep.Holla@arm.com>]

On 17/01/14 12:24, Hanjun Guo wrote:
> The _PDC (Processor Driver Capabilities) object provides OSPM a
> mechanism to convey to the platform the capabilities supported
> by OSPM for processor power management.
> 
> OSPM evaluates _PDC prior to evaluating any other processor
> power management objects returning configuration information.
> 
> This patch introduces the skeleton of _PDC related file to make
> ACPI core can be compiled on ARM64.
> 
> Signed-off-by: Al Stone <al.stone@linaro.org>
> Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
> Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
> ---
>  arch/arm64/include/asm/acpi.h      |   32 ++++++++++++++++++++++++++++++++
>  arch/arm64/include/asm/processor.h |    2 ++
>  arch/arm64/kernel/process.c        |    3 +++
>  3 files changed, 37 insertions(+)
>  create mode 100644 arch/arm64/include/asm/acpi.h
> 
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> new file mode 100644
> index 0000000..cf19dc6
> --- /dev/null
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -0,0 +1,32 @@
> +/*
> + *  Copyright (C) 2013, Al Stone <al.stone@linaro.org>
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + */
> +
> +#ifndef _ASM_ARM64_ACPI_H
> +#define _ASM_ARM64_ACPI_H
> +
> +static inline bool arch_has_acpi_pdc(void)
> +{
> +	return false;	/* always false for now */
> +}
> +
> +static inline void arch_acpi_set_pdc_bits(u32 *buf)
> +{
> +	return;
> +}
> +
> +#endif /*_ASM_ARM64_ACPI_H*/
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index 45b20cd..50ce951 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -162,6 +162,8 @@ static inline void spin_lock_prefetch(const void *x)
>  
>  #define HAVE_ARCH_PICK_MMAP_LAYOUT
>  
> +extern unsigned long    boot_option_idle_override;
> +
>  #endif
>  
>  #endif /* __ASM_PROCESSOR_H */
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index de17c89..13d3d7f 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -89,6 +89,9 @@ void arch_cpu_idle_prepare(void)
>  	local_fiq_enable();
>  }
>  
> +unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
> +EXPORT_SYMBOL(boot_option_idle_override);
> +

This is what I mentioned in other email. Do we really foresee use of this in
ARM64 or it's just added to avoid build issues ?

Regards,
Sudeep