On Thu, Mar 20, 2014 at 05:41:00PM +0530, Gautham R. Shenoy wrote:
> From: "Gautham R. Shenoy" <e...@linux.vnet.ibm.com>
>
> The current frequency of a cpu is reported through the sysfs file
> cpuinfo_cur_freq. This requires the driver to implement a
> "->get(unsigned int cpu)" method which will return the current
> operating frequency.
>
> Implement a function named powernv_cpufreq_get() which reads the local
> pstate from the PMSR and returns the corresponding frequency.
>
> Set the powernv_cpufreq_driver.get hook to powernv_cpufreq_get().
Forgot to add
Reviewed-by: Preeti U Murthy <pre...@linux.vnet.ibm.com>
>
> Signed-off-by: Gautham R. Shenoy <e...@linux.vnet.ibm.com>
> ---
> drivers/cpufreq/powernv-cpufreq.c | 38 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 38 insertions(+)
>
> diff --git a/drivers/cpufreq/powernv-cpufreq.c
> b/drivers/cpufreq/powernv-cpufreq.c
> index 46bee8a..ef6ed8c 100644
> --- a/drivers/cpufreq/powernv-cpufreq.c
> +++ b/drivers/cpufreq/powernv-cpufreq.c
> @@ -206,6 +206,43 @@ static inline void set_pmspr(unsigned long sprn,
> unsigned long val)
> BUG();
> }
>
> +/*
> + * Computes the current frequency on this cpu
> + * and stores the result in *ret_freq.
> + */
> +static void powernv_read_cpu_freq(void *ret_freq)
> +{
> + unsigned long pmspr_val;
> + s8 local_pstate_id;
> + int *cur_freq, freq, pstate_id;
> +
> + cur_freq = (int *)ret_freq;
> + pmspr_val = get_pmspr(SPRN_PMSR);
> +
> + /* The local pstate id corresponds bits 48..55 in the PMSR.
> + * Note: Watch out for the sign! */
> + local_pstate_id = (pmspr_val >> 48) & 0xFF;
> + pstate_id = local_pstate_id;
> +
> + freq = pstate_id_to_freq(pstate_id);
> + pr_debug("cpu %d pmsr %lx pstate_id %d frequency %d \n",
> + smp_processor_id(), pmspr_val, pstate_id, freq);
> + *cur_freq = freq;
> +}
> +
> +/*
> + * Returns the cpu frequency as reported by the firmware for 'cpu'.
> + * This value is reported through the sysfs file cpuinfo_cur_freq.
> + */
> +unsigned int powernv_cpufreq_get(unsigned int cpu)
> +{
> + int ret_freq;
> +
> + smp_call_function_any(cpu_sibling_mask(cpu), powernv_read_cpu_freq,
> + &ret_freq, 1);
> + return ret_freq;
> +}
> +
> static void set_pstate(void *pstate)
> {
> unsigned long val;
> @@ -297,6 +334,7 @@ static int powernv_cpufreq_target(struct cpufreq_policy
> *policy,
> static struct cpufreq_driver powernv_cpufreq_driver = {
> .verify = powernv_cpufreq_verify,
> .target = powernv_cpufreq_target,
> + .get = powernv_cpufreq_get,
> .init = powernv_cpufreq_cpu_init,
> .exit = powernv_cpufreq_cpu_exit,
> .name = "powernv-cpufreq",
> --
> 1.8.3.1
>
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