linux-kernel - Re: [PATCH V4] ARM: mach-shmobile: Don't init CNTVOFF/counter if PSCI is available

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Message-ID: <4e712484-d6a4-e358-ea66-51dfcee18b0d@arm.com>
Date:   Tue, 14 May 2019 17:13:50 +0100
From:   Julien Grall <julien.grall@....com>
To:     Oleksandr Tyshchenko <olekstysh@...il.com>,
        linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     horms@...ge.net.au, magnus.damm@...il.com, linux@...linux.org.uk,
        geert@...ux-m68k.org,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>
Subject: Re: [PATCH V4] ARM: mach-shmobile: Don't init CNTVOFF/counter if PSCI
 is available

Hi,

On 14/05/2019 17:06, Oleksandr Tyshchenko wrote:
> diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c b/arch/arm/mach-shmobile/setup-rcar-gen2.c
> index eea60b2..64e3abd 100644
> --- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
> +++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
> @@ -17,6 +17,7 @@
>   #include <linux/of.h>
>   #include <linux/of_fdt.h>
>   #include <linux/of_platform.h>
> +#include <linux/psci.h>
>   #include <asm/mach/arch.h>
>   #include <asm/secure_cntvoff.h>
>   #include "common.h"
> @@ -63,6 +64,15 @@ void __init rcar_gen2_timer_init(void)
>   	void __iomem *base;
>   	u32 freq;
>   
> +	/*
> +	 * If PSCI is available then most likely we are running on PSCI-enabled
> +	 * U-Boot which, we assume, has already taken care of resetting CNTVOFF
> +	 * and updating counter module before switching to non-secure mode
> +	 * and we don't need to.
> +	 */
> +	if (psci_ops.cpu_on) > +		goto skip_update;
Are you sure this is working when ARM_PSCI_FW is not selected? Is it possible to 
have a .config for RCAR without ARM_PSCI_FW?

Cheers,

-- 
Julien Grall