linux-kernel - Re: [PATCH/RESEND] clocksource/arm_arch_timer: Map frame with of_io_request_and

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Message-ID: <5807255A.8060906@arm.com>
Date:   Wed, 19 Oct 2016 08:48:42 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Stephen Boyd <sboyd@...eaurora.org>,
        Mark Rutland <mark.rutland@....com>
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Daniel Lezcano <daniel.lezcano@...aro.org>
Subject: Re: [PATCH/RESEND] clocksource/arm_arch_timer: Map frame with
 of_io_request_and_map()

On 19/10/16 00:45, Stephen Boyd wrote:
> Let's use the of_io_request_and_map() API so that the frame
> region is protected and shows up in /proc/iomem.
> 
> Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
> ---
>  drivers/clocksource/arm_arch_timer.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 73c487da6d2a..cbfa3bc5be75 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -964,7 +964,8 @@ static int __init arch_timer_mem_init(struct device_node *np)
>  	}
>  
>  	ret= -ENXIO;
> -	base = arch_counter_base = of_iomap(best_frame, 0);
> +	base = arch_counter_base = of_io_request_and_map(best_frame, 0,
> +							 "arch_mem_timer");
>  	if (!base) {
>  		pr_err("arch_timer: Can't map frame's registers\n");
>  		goto out;
> 

Careful here: of_io_request_and_map() returns an ERR_PTR() on failure,
while of_iomap just returns NULL. You want to change the error handling
if you're going down that road.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...