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

From: Colin Cross
Date: Tue Feb 22 2011 - 03:05:14 EST


On Mon, Feb 21, 2011 at 9:43 PM, Olof Johansson <olof@xxxxxxxxx> wrote:
> Hi,
>
> On Mon, Feb 21, 2011 at 6:39 PM, Colin Cross <ccross@xxxxxxxxxxx> 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@xxxxxxxxxxx>
>> ---
>>  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.
It doesn't need to be an early_param, I can make it a __setup.

> Also, Documentation/kernel-parameters.txt should be updated with it.
Is it really worth adding every debug flag on every platform to
kernel-parametes.txt? I could add the flag to the warning message
instead.
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