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SubjectRe: [PATCH] cpufreq: powernv: Remove global pstate ramp-down timer in POWER9
On 25-04-18, 11:44, Shilpasri G Bhat wrote:
> POWER9 doesnot support global pstate requests for the chip. So remove
> the timer logic which slowly ramps down the global pstate in P9
> platforms.
>
> Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
> ---
> drivers/cpufreq/powernv-cpufreq.c | 23 ++++++++++++++++++-----
> 1 file changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
> index 0591874..71f8682 100644
> --- a/drivers/cpufreq/powernv-cpufreq.c
> +++ b/drivers/cpufreq/powernv-cpufreq.c
> @@ -750,8 +750,13 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
>
> cur_msec = jiffies_to_msecs(get_jiffies_64());
>
> - spin_lock(&gpstates->gpstate_lock);
> freq_data.pstate_id = idx_to_pstate(new_index);
> + if (!gpstates) {
> + freq_data.gpstate_id = freq_data.pstate_id;
> + goto no_gpstate;
> + }
> +
> + spin_lock(&gpstates->gpstate_lock);
>
> if (!gpstates->last_sampled_time) {
> gpstate_idx = new_index;
> @@ -801,6 +806,7 @@ static int powernv_cpufreq_target_index(struct cpufreq_policy *policy,
>
> spin_unlock(&gpstates->gpstate_lock);
>
> +no_gpstate:
> /*
> * Use smp_call_function to send IPI and execute the
> * mtspr on target CPU. We could do that without IPI
> @@ -835,6 +841,13 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
> kernfs_put(kn);
> }
>
> + policy->freq_table = powernv_freqs;
> + policy->fast_switch_possible = true;
> +
> + if (pvr_version_is(PVR_POWER9))
> + return 0;
> +
> + /* Initialise Gpstate ramp-down timer only on POWER8 */
> gpstates = kzalloc(sizeof(*gpstates), GFP_KERNEL);
> if (!gpstates)
> return -ENOMEM;
> @@ -849,15 +862,14 @@ static int powernv_cpufreq_cpu_init(struct cpufreq_policy *policy)
> msecs_to_jiffies(GPSTATE_TIMER_INTERVAL);
> spin_lock_init(&gpstates->gpstate_lock);
>
> - policy->freq_table = powernv_freqs;
> - policy->fast_switch_possible = true;
> return 0;
> }
>
> static int powernv_cpufreq_cpu_exit(struct cpufreq_policy *policy)
> {
> /* timer is deleted in cpufreq_cpu_stop() */
> - kfree(policy->driver_data);
> + if (policy->driver_data)
> + kfree(policy->driver_data);
>
> return 0;
> }
> @@ -990,7 +1002,8 @@ static void powernv_cpufreq_stop_cpu(struct cpufreq_policy *policy)
> freq_data.pstate_id = idx_to_pstate(powernv_pstate_info.min);
> freq_data.gpstate_id = idx_to_pstate(powernv_pstate_info.min);
> smp_call_function_single(policy->cpu, set_pstate, &freq_data, 1);
> - del_timer_sync(&gpstates->timer);
> + if (gpstates)
> + del_timer_sync(&gpstates->timer);
> }
>
> static unsigned int powernv_fast_switch(struct cpufreq_policy *policy,

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

--
viresh

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