Re: [PATCH] cpufreq: ppc-corenet-cpu-freq: do_div use quotient

On 5 June 2014 03:05, Ed Swarthout <[email protected]> wrote:
> 6712d2931933ada259b82f06c03a855b19937074 (cpufreq:
> ppc-corenet-cpufreq: Fix __udivdi3 modpost error) used the remainder
> from do_div instead of the quotient. Fix that and add one to ensure
> minimum is met.

This should have been caught with reviews, I remember I saw the
change but didn't bother checking implementation of do_div()..

I get a '-1' for this review, bad.

> Signed-off-by: Ed Swarthout <[email protected]>
> ---
>
> Tested on t4240qds and p4080ds.
>
> https://patchwork.kernel.org/patch/4296811/
> http://patchwork.ozlabs.org/patch/356096/
>
>  drivers/cpufreq/ppc-corenet-cpufreq.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
> index 0af618a..3607070 100644
> --- a/drivers/cpufreq/ppc-corenet-cpufreq.c
> +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
> @@ -138,7 +138,7 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
>         struct cpufreq_frequency_table *table;
>         struct cpu_data *data;
>         unsigned int cpu = policy->cpu;
> -       u64 transition_latency_hz;
> +       u64 u64temp;

Why do you want to rename this?

>         np = of_get_cpu_node(cpu, NULL);
>         if (!np)
> @@ -206,9 +206,10 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
>         for_each_cpu(i, per_cpu(cpu_mask, cpu))
>                 per_cpu(cpu_data, i) = data;
>
> -       transition_latency_hz = 12ULL * NSEC_PER_SEC;
> -       policy->cpuinfo.transition_latency =
> -               do_div(transition_latency_hz, fsl_get_sys_freq());
> +       /* Minimum transition latency is 12 platform clocks */
> +       u64temp = 12ULL * NSEC_PER_SEC;
> +       do_div(u64temp, fsl_get_sys_freq());
> +       policy->cpuinfo.transition_latency = u64temp + 1;

Why this + 1 here ?

>         of_node_put(np);
>
> --
> 1.9.1
>