linux-kernel - Re: [PATCH 7/7] ARM: tegra: clock: Disable clocks left on by bootloader

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Date:	Mon, 21 Feb 2011 21:43:19 -0800
From:	Olof Johansson <olof@...om.net>
To:	Colin Cross <ccross@...roid.com>
Cc:	linux-tegra@...r.kernel.org, konkers@...roid.com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	mike@...pulab.co.il, Russell King <linux@....linux.org.uk>
Subject: Re: [PATCH 7/7] ARM: tegra: clock: Disable clocks left on by bootloader

Hi,

On Mon, Feb 21, 2011 at 6:39 PM, Colin Cross <ccross@...roid.com> wrote:
> Iterates through all clocks, disabling any for which the
> refcount is 0 but the clock init detected the bootloader
> left the clock on.  Can be disabled with command line
> tegra_clock.disable_boot_clocks=N
>
> Signed-off-by: Colin Cross <ccross@...roid.com>
> ---
>  arch/arm/mach-tegra/clock.c |   44 +++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 44 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c
> index e028320..6d686ff 100644
> --- a/arch/arm/mach-tegra/clock.c
> +++ b/arch/arm/mach-tegra/clock.c
> @@ -33,6 +33,9 @@
>  #include "board.h"
>  #include "clock.h"
>
> +#undef MODULE_PARAM_PREFIX
> +#define MODULE_PARAM_PREFIX "tegra_clock."
> +
>  /*
>  * Locking:
>  *
> @@ -416,6 +419,47 @@ void tegra_sdmmc_tap_delay(struct clk *c, int delay)
>        spin_unlock_irqrestore(&c->spinlock, flags);
>  }
>
> +static bool tegra_disable_boot_clocks = true;
> +module_param_named(disable_boot_clocks, tegra_disable_boot_clocks, bool,
> +       S_IRUGO | S_IWUSR | S_IWGRP);

I suggest doing this as an early_param instead. I know it's not truly
an early param, but it's the easier way to do non-module bootargs,
i.e. by not requiring a (fake) module prefix. It'd be a little
cleaner, in my opinion. The variable name itself is unique enough to
not need a module prefix for namespace reasons.

Also, Documentation/kernel-parameters.txt should be updated with it.


-Olof
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