linux-kernel - Re: [PATCH RFC 7/9] cpufreq: qcom: Add support to update cpu node's OPP tables

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Message-ID: <20190410103316.sxev2f54klemq2p6@vireshk-i7>
Date:   Wed, 10 Apr 2019 16:03:16 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Sibi Sankar <sibis@...eaurora.org>
Cc:     robh+dt@...nel.org, andy.gross@...aro.org,
        myungjoo.ham@...sung.com, kyungmin.park@...sung.com,
        rjw@...ysocki.net, nm@...com, sboyd@...nel.org,
        georgi.djakov@...aro.org, bjorn.andersson@...aro.org,
        david.brown@...aro.org, mark.rutland@....com,
        linux-kernel@...r.kernel.org, linux-arm-msm-owner@...r.kernel.org,
        devicetree@...r.kernel.org, rnayak@...eaurora.org,
        cw00.choi@...sung.com, linux-pm@...r.kernel.org,
        evgreen@...omium.org, daidavid1@...eaurora.org,
        dianders@...omium.org
Subject: Re: [PATCH RFC 7/9] cpufreq: qcom: Add support to update cpu node's
 OPP tables

On 28-03-19, 20:58, Sibi Sankar wrote:
> Add support to parse and update OPP tables attached to the cpu nodes.
> 
> Signed-off-by: Sibi Sankar <sibis@...eaurora.org>
> ---
>  drivers/cpufreq/qcom-cpufreq-hw.c | 29 +++++++++++++++++++++++++++--
>  1 file changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/cpufreq/qcom-cpufreq-hw.c b/drivers/cpufreq/qcom-cpufreq-hw.c
> index 4b0b50403901..5c268dd2346c 100644
> --- a/drivers/cpufreq/qcom-cpufreq-hw.c
> +++ b/drivers/cpufreq/qcom-cpufreq-hw.c
> @@ -73,6 +73,25 @@ static unsigned int qcom_cpufreq_hw_fast_switch(struct cpufreq_policy *policy,
>  	return policy->freq_table[index].frequency;
>  }
>  
> +static int qcom_find_update_opp(struct device *cpu_dev, unsigned long freq,
> +				unsigned long volt)
> +{
> +	int ret;
> +	struct dev_pm_opp *opp;
> +
> +	opp = dev_pm_opp_find_freq_exact(cpu_dev, freq, true);
> +	if (IS_ERR(opp)) {
> +		ret = dev_pm_opp_add(cpu_dev, freq, volt);

With my comment on the other patch, you can just call
dev_pm_opp_update_voltage() and if that fails then call dev_pm_opp_add().

> +	} else {
> +		dev_pm_opp_disable(cpu_dev, freq);
> +		ret = dev_pm_opp_update_voltage(cpu_dev, freq, volt);
> +		dev_pm_opp_enable(cpu_dev, freq);

Perhaps no one else should be using the CPU OPP table at this point of time and
so we can get away with disable and enable stuff ? Just add a comment on why
that works.

> +		dev_pm_opp_put(opp);
> +	}
> +
> +	return ret;
> +}
> +
>  static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
>  				    struct cpufreq_policy *policy,
>  				    void __iomem *base)
> @@ -81,11 +100,16 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
>  	u32 volt;
>  	unsigned int max_cores = cpumask_weight(policy->cpus);
>  	struct cpufreq_frequency_table	*table;
> +	int ret;
>  
>  	table = kcalloc(LUT_MAX_ENTRIES + 1, sizeof(*table), GFP_KERNEL);
>  	if (!table)
>  		return -ENOMEM;
>  
> +	ret = dev_pm_opp_of_add_table(cpu_dev);
> +	if (ret)
> +		dev_dbg(cpu_dev, "Couldn't add OPP table\n");
> +
>  	for (i = 0; i < LUT_MAX_ENTRIES; i++) {
>  		data = readl_relaxed(base + REG_FREQ_LUT +
>  				      i * LUT_ROW_SIZE);
> @@ -104,7 +128,7 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
>  
>  		if (freq != prev_freq && core_count == max_cores) {
>  			table[i].frequency = freq;
> -			dev_pm_opp_add(cpu_dev, freq * 1000, volt);
> +			qcom_find_update_opp(cpu_dev, freq * 1000, volt);
>  			dev_dbg(cpu_dev, "index=%d freq=%d, core_count %d\n", i,
>  				freq, core_count);
>  		} else {
> @@ -125,7 +149,8 @@ static int qcom_cpufreq_hw_read_lut(struct device *cpu_dev,
>  			if (prev_cc != max_cores) {
>  				prev->frequency = prev_freq;
>  				prev->flags = CPUFREQ_BOOST_FREQ;
> -				dev_pm_opp_add(cpu_dev,	prev_freq * 1000, volt);
> +				qcom_find_update_opp(cpu_dev, prev_freq * 1000,
> +						     volt);
>  			}
>  
>  			break;
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project

-- 
viresh