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SubjectRe: [PATCH 1/2] cpufreq: arm_big_little: check if the frequency is set correctly
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On 27 April 2015 at 15:21, Sudeep Holla <sudeep.holla@arm.com> wrote:
> The actual frequency is set through "clk_change_rate" which is void
> function. If the underlying hardware fails and returns error, the error
> is lost in the clk layer. In order to track such failures, we need to
> read back the frequency(just the cached value as clk_recalc called after
> clk->ops->set_rate gets the frequency)
>
> This patch adds check to see if the frequency is set correctly or if
> they were any hardware failures and sends the appropriate errors to the
> cpufreq core.
>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Reviewed-by: Michael Turquette <mike.turquette@linaro.org>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
> drivers/cpufreq/arm_big_little.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/cpufreq/arm_big_little.c b/drivers/cpufreq/arm_big_little.c
> index e1a6ba66a7f5..f65e19f340d0 100644
> --- a/drivers/cpufreq/arm_big_little.c
> +++ b/drivers/cpufreq/arm_big_little.c
> @@ -186,6 +186,15 @@ bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
> mutex_unlock(&cluster_lock[old_cluster]);
> }
>
> + /*
> + * FIXME: clk_set_rate has to handle the case where clk_change_rate
> + * can fail due to hardware or firmware issues. Until the clk core
> + * layer is fixed, we can check here. In most of the cases we will
> + * be reading only the cached value anyway. This needs to be removed
> + * once clk core is fixed.
> + */
> + if (bL_cpufreq_get_rate(cpu) != new_rate)
> + return -EIO;
> return 0;
> }

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>


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