linux-kernel - Re: [PATCH 6/8] cppc_cpufreq: clarify support for coordination types

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Message-ID: <20201109070702.2hod2xh7fddobnkl@vireshk-i7>
Date:   Mon, 9 Nov 2020 12:37:02 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Ionela Voinescu <ionela.voinescu@....com>
Cc:     rjw@...ysocki.net, lenb@...nel.org, sudeep.holla@....com,
        morten.rasmussen@....com, jeremy.linton@....com,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/8] cppc_cpufreq: clarify support for coordination types

On 05-11-20, 12:55, Ionela Voinescu wrote:
> The previous coordination type handling in the cppc_cpufreq init code
> created some confusion: the comment mentioned "Support only SW_ANY for
> now" while only the SW_ALL/ALL case resulted in a failure. The other
> coordination types (HW_ALL/HW, NONE) were silently supported.
> 
> Clarify support for coordination types while describing in comments the
> intended behavior.
> 
> Signed-off-by: Ionela Voinescu <ionela.voinescu@....com>
> Cc: Rafael J. Wysocki <rjw@...ysocki.net>
> Cc: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/cpufreq/cppc_cpufreq.c | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index fd2daeb59b49..60ac7f8049b5 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -363,11 +363,22 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
>  	policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu);
>  	policy->shared_type = domain->shared_type;
>  
> -	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {
> +	switch (policy->shared_type) {
> +	case CPUFREQ_SHARED_TYPE_HW:
> +	case CPUFREQ_SHARED_TYPE_NONE:
> +		/* Nothing to be done - we'll have a policy for each CPU */
> +		break;
> +	case CPUFREQ_SHARED_TYPE_ANY:
> +		/*
> +		 * All CPUs in the domain will share a policy and all cpufreq
> +		 * operations will use a single cppc_cpudata structure stored
> +		 * in policy->driver_data.
> +		 */
>  		cpumask_copy(policy->cpus, domain->shared_cpu_map);
> -	} else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
> -		/* Support only SW_ANY for now. */
> -		pr_debug("Unsupported CPU co-ord type\n");
> +		break;
> +	default:
> +		pr_info("Unsupported cpufreq CPU co-ord type: %d\n",
> +			policy->shared_type);
>  		return -EFAULT;
>  	}
>  

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

-- 
viresh