Re: [PATCH v3 1/3] cpufreq: add cpufreq_driver_resolve_freq()
From: Viresh Kumar
Date: Thu Jul 21 2016 - 15:59:38 EST
On 13-07-16, 13:25, Steve Muckle wrote:
> Cpufreq governors may need to know what a particular target frequency
> maps to in the driver without necessarily wanting to set the frequency.
> Support this operation via a new cpufreq API,
> cpufreq_driver_resolve_freq(). This API returns the lowest driver
> frequency equal or greater than the target frequency
> (CPUFREQ_RELATION_L), subject to any policy (min/max) or driver
> limitations. The mapping is also cached in the policy so that a
> subsequent fast_switch operation can avoid repeating the same lookup.
> The API will call a new cpufreq driver callback, resolve_freq(), if it
> has been registered by the driver. Otherwise the frequency is resolved
> via cpufreq_frequency_table_target(). Rather than require ->target()
> style drivers to provide a resolve_freq() callback it is left to the
> caller to ensure that the driver implements this callback if necessary
> to use cpufreq_driver_resolve_freq().
> Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Signed-off-by: Steve Muckle <smuckle@xxxxxxxxxx>
> drivers/cpufreq/cpufreq.c | 25 +++++++++++++++++++++++++
> include/linux/cpufreq.h | 16 ++++++++++++++++
> 2 files changed, 41 insertions(+)
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index 118b4f30a406..b696baeb249d 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -492,6 +492,29 @@ void cpufreq_disable_fast_switch(struct cpufreq_policy *policy)
> + * cpufreq_driver_resolve_freq - Map a target frequency to a driver-supported
> + * one.
> + * @target_freq: target frequency to resolve.
> + *
> + * The target to driver frequency mapping is cached in the policy.
> + *
> + * Return: Lowest driver-supported frequency greater than or equal to the
> + * given target_freq, subject to policy (min/max) and driver limitations.
> + */
> +unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
> + unsigned int target_freq)
> + target_freq = clamp_val(target_freq, policy->min, policy->max);
> + policy->cached_target_freq = target_freq;
> + if (cpufreq_driver->resolve_freq)
> + return cpufreq_driver->resolve_freq(policy, target_freq);
Any reason why we still have this call around ? I thought the whole
attempt I made was to get rid of this :)
The core can do this pretty much now by itself, why do we still want
Also, your series doesn't add a user for it yet, so better drop it for