linux-kernel - Re: [PATCH 02/11] ARM: remove extra timer-sp control register clearing

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Date:	Thu, 21 Mar 2013 18:58:08 +0100
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Rob Herring <robherring2@...il.com>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	devicetree-discuss@...ts.ozlabs.org, Arnd Bergmann <arnd@...db.de>,
	Russell King <linux@....linux.org.uk>,
	haojian.zhuang@...aro.org, pawel.moll@....com,
	john.stultz@...aro.org, tglx@...utronix.de,
	Rob Herring <rob.herring@...xeda.com>
Subject: Re: [PATCH 02/11] ARM: remove extra timer-sp control register clearing

On Wed, Mar 20, 2013 at 11:54 PM, Rob Herring <robherring2@...il.com> wrote:

> From: Rob Herring <rob.herring@...xeda.com>
>
> The timer-sp initialization code clears the control register before
> initializing the timers, so every platform doing this is redundant.
>
> For unused timers, we should not care what state they are in.
>
> Signed-off-by: Rob Herring <rob.herring@...xeda.com>
(...)
> diff --git a/arch/arm/mach-integrator/integrator_ap.c b/arch/arm/mach-integrator/integrator_ap.c
> index ea96144..4cb322d 100644
> --- a/arch/arm/mach-integrator/integrator_ap.c
> +++ b/arch/arm/mach-integrator/integrator_ap.c
> @@ -643,10 +643,6 @@ static void __init ap_timer_init(void)
>         clk_prepare_enable(clk);
>         rate = clk_get_rate(clk);
>
> -       writel(0, TIMER0_VA_BASE + TIMER_CTRL);
> -       writel(0, TIMER1_VA_BASE + TIMER_CTRL);
> -       writel(0, TIMER2_VA_BASE + TIMER_CTRL);
> -

As noted this is not an init function for timer-sp.c so please drop this
hunk of the patch. Maybe this zeroing is pointless but that would
be a separate patch that I can test.

> diff --git a/arch/arm/mach-integrator/integrator_cp.c b/arch/arm/mach-integrator/integrator_cp.c
> index 2b0db82..c68e7d8 100644
> --- a/arch/arm/mach-integrator/integrator_cp.c
> +++ b/arch/arm/mach-integrator/integrator_cp.c
> @@ -33,7 +33,6 @@
>  #include <mach/platform.h>
>  #include <asm/setup.h>
>  #include <asm/mach-types.h>
> -#include <asm/hardware/arm_timer.h>

What doe this change has to do with $SUBJECT?

>  #include <asm/hardware/icst.h>
>
>  #include <mach/cm.h>
> @@ -267,7 +266,6 @@ static void __init cp_of_timer_init(void)
>         base = of_iomap(node, 0);
>         if (WARN_ON(!base))
>                 return;
> -       writel(0, base + TIMER_CTRL);
>         sp804_clocksource_init(base, node->name);
>
>         err = of_property_read_string(of_aliases,
> @@ -279,7 +277,6 @@ static void __init cp_of_timer_init(void)
>         if (WARN_ON(!base))
>                 return;
>         irq = irq_of_parse_and_map(node, 0);
> -       writel(0, base + TIMER_CTRL);
>         sp804_clockevents_init(base, irq, node->name);
>  }
>
> @@ -510,10 +507,6 @@ static void __init intcp_init_irq(void)
>
>  static void __init cp_timer_init(void)
>  {
> -       writel(0, TIMER0_VA_BASE + TIMER_CTRL);
> -       writel(0, TIMER1_VA_BASE + TIMER_CTRL);
> -       writel(0, TIMER2_VA_BASE + TIMER_CTRL);
> -
>         sp804_clocksource_init(TIMER2_VA_BASE, "timer2");
>         sp804_clockevents_init(TIMER1_VA_BASE, IRQ_TIMERINT1, "timer1");
>  }

The rest of the changes to integrator_cp.c looks OK...

Yours,
Linus Walleij
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