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

[Sibi Sankar]

On 2019-04-10 16:03, Viresh Kumar wrote:
> 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@xxxxxxxxxxxxxx>
> > ---
> >  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().

yeah that should simplify things.

Also through the above approach I cannot
really disable opps that the OSM does not
support. I can only try enabling opp's that
OSM supports. But that would require all
opp's nodes to start with "disabled" but
that is not allowed I guess.

> > +	} 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.

we can get away without enable/disable here

> > +		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

--
-- Sibi Sankar --
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.