Re: [PATCH v3 1/2] thermal: mediatek: Add cpu power cooling model.

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On Wed, 2015-11-04 at 11:40 -0800, Eduardo Valentin wrote:
> On Thu, Oct 22, 2015 at 08:02:38PM +0800, Dawei Chien wrote:
> > This power model is base on Intelligent Power Allocation (IPA)
> > technical, requires that the operating-points of the CPUs are
> > registered using the kernel's opp library and the
> > `cpufreq_frequency_table` is assigned to the `struct device`
> > of the cpu MT8173.
> > 
> > Signed-off-by: Dawei.Chien <dawei.chien@xxxxxxxxxxxx>
> > ---
> > This patch is base on
> > https://patchwork.kernel.org/patch/7034601/
> > ---
> >  drivers/cpufreq/mt8173-cpufreq.c |  152 ++++++++++++++++++++++++++++++++++++--
> 
> Given that you are proposing this on top a DT binding, why reading a
> table of static power model applicable only to mt8173 cpufreq driver?
> 
> I have not seen anything specific (formula etc) that prevents this code
> to be generalized to other CPUs.
> 
> Can you please help me to understand?
> 
> BR,
This is because our platform currently only support mt8173_cpufreq.c, so
that I only add static power model for our owner IC.

Please understanding that I wouldn't give a DT binding document since I
will remove static power table on next version, but I can try to explain
it.

As far as I know, static power is somewhat leakage of CPU clusters, so
that we hardly to find a formula, which can suitable all kinds of CPUs
since leakage is different. In ARM IPA framework, static power only need
to be defined by who register cpufreq_power_cooling_register. The
voltage/power table is just one way to present leakage power of CPUs.

Actually, static power is optional since dynamic power is much more than
static power.

> >  1 file changed, 144 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/cpufreq/mt8173-cpufreq.c b/drivers/cpufreq/mt8173-cpufreq.c
> > index 49caed2..23c19c5 100644
> > --- a/drivers/cpufreq/mt8173-cpufreq.c
> > +++ b/drivers/cpufreq/mt8173-cpufreq.c
> > @@ -29,6 +29,16 @@
> >  #define MAX_VOLT_LIMIT		(1150000)
> >  #define VOLT_TOL		(10000)
> >  
> > +struct mtk_cpu_static_power {
> > +	unsigned long voltage;
> > +	unsigned int power;
> > +};
> > +
> > +static struct mtk_cpu_static_power *mtk_ca53_static_power_table;
> > +static struct mtk_cpu_static_power *mtk_ca57_static_power_table;
> > +static int mtk_ca53_static_table_length;
> > +static int mtk_ca57_static_table_length;
> > +
> >  /*
> >   * The struct mtk_cpu_dvfs_info holds necessary information for doing CPU DVFS
> >   * on each CPU power/clock domain of Mediatek SoCs. Each CPU cluster in
> > @@ -51,6 +61,110 @@ struct mtk_cpu_dvfs_info {
> >  	bool need_voltage_tracking;
> >  };
> >  
> > +unsigned int mtk_cpufreq_lookup_power(const struct mtk_cpu_static_power *table,
> > +		unsigned int count, unsigned long voltage)
> > +{
> > +	int i;
> > +
> > +	for (i = 0; i < count; i++) {
> > +		if (voltage <= table[i].voltage)
> > +			return table[i].power;
> > +	}
> > +
> > +	return table[count - 1].power;
> > +}
> > +
> > +int mtk_cpufreq_get_static(cpumask_t *cpumask, int interval,
> > +		unsigned long voltage, u32 *power)
> > +{
> > +	int nr_cpus = cpumask_weight(cpumask);
> > +
> > +	*power = 0;
> > +
> > +	if (nr_cpus) {
> > +		if (cpumask_test_cpu(0, cpumask))
> > +			*power += mtk_cpufreq_lookup_power(
> > +					mtk_ca53_static_power_table,
> > +					mtk_ca53_static_table_length,
> > +					voltage);
> > +
> > +		if (cpumask_test_cpu(2, cpumask))
> > +			*power += mtk_cpufreq_lookup_power(
> > +					mtk_ca57_static_power_table,
> > +					mtk_ca57_static_table_length,
> > +					voltage);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +unsigned int mtk_get_power_table_info(struct cpufreq_policy *policy,
> > +		struct device_node *np, const char *node_name)
> > +{
> > +	int mtk_static_table_length;
> > +	const struct property *prop;
> > +	struct mtk_cpu_dvfs_info *info = policy->driver_data;
> > +	struct device *cpu_dev = info->cpu_dev;
> > +	const __be32 *val;
> > +	int nr, i;
> > +
> > +	prop = of_find_property(np, node_name, NULL);
> > +
> > +	if (!prop) {
> > +		pr_err("failed to get static-power-points\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	if (!prop->value) {
> > +		pr_err("failed to get static power array data\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	nr = prop->length / sizeof(u32);
> > +
> > +	if (nr % 2) {
> > +		pr_err("Invalid OPP list\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	mtk_static_table_length = nr / 2;
> > +
> > +	if (cpumask_test_cpu(0, policy->related_cpus)) {
> > +		mtk_ca53_static_table_length = mtk_static_table_length;
> > +		mtk_ca53_static_power_table = devm_kcalloc(cpu_dev,
> > +					mtk_static_table_length,
> > +					sizeof(*mtk_ca53_static_power_table),
> > +					GFP_KERNEL);
> > +
> > +		val = prop->value;
> > +		for (i = 0; i < mtk_static_table_length; ++i) {
> > +			unsigned long voltage = be32_to_cpup(val++);
> > +			unsigned int power = be32_to_cpup(val++);
> > +
> > +			mtk_ca53_static_power_table[i].voltage = voltage;
> > +			mtk_ca53_static_power_table[i].power = power;
> > +			pr_info("volt:%ld uv, power:%d mW\n", voltage, power);
> > +		}
> > +	} else {
> > +                mtk_ca57_static_table_length = mtk_static_table_length;
> > +		mtk_ca57_static_power_table = devm_kcalloc(cpu_dev,
> > +					mtk_static_table_length,
> > +					sizeof(*mtk_ca57_static_power_table),
> > +					GFP_KERNEL);
> > +		val = prop->value;
> > +		for (i = 0; i < mtk_static_table_length; ++i) {
> > +			unsigned long voltage = be32_to_cpup(val++);
> > +			unsigned int power = be32_to_cpup(val++);
> > +
> > +			mtk_ca57_static_power_table[i].voltage = voltage;
> > +			mtk_ca57_static_power_table[i].power = power;
> > +			pr_info("volt:%ld uv, power:%d mW\n", voltage, power);
> > +		}
> > +	}
> > +
> > +	return	0;
> > +}
> > +
> >  static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
> >  					int new_vproc)
> >  {
> > @@ -267,20 +381,40 @@ static void mtk_cpufreq_ready(struct cpufreq_policy *policy)
> >  {
> >  	struct mtk_cpu_dvfs_info *info = policy->driver_data;
> >  	struct device_node *np = of_node_get(info->cpu_dev->of_node);
> > +	u32 capacitance;
> > +	int ret;
> >  
> >  	if (WARN_ON(!np))
> >  		return;
> >  
> >  	if (of_find_property(np, "#cooling-cells", NULL)) {
> > -		info->cdev = of_cpufreq_cooling_register(np,
> > -							 policy->related_cpus);
> >  
> > -		if (IS_ERR(info->cdev)) {
> > -			dev_err(info->cpu_dev,
> > -				"running cpufreq without cooling device: %ld\n",
> > -				PTR_ERR(info->cdev));
> > +		if (!info->cdev) {
> > +
> > +			of_property_read_u32(np,
> > +					"dynamic-power-coefficient",
> > +					&capacitance);
> > +
> > +			ret = mtk_get_power_table_info(policy, np,
> > +						"static-power-points");
> > +			if (ret) {
> > +                                dev_err(info->cpu_dev,
> > +                                        "cpufreq without static-points: %d\n",
> > +                                        ret);
> > +			}
> > +
> > +			info->cdev = of_cpufreq_power_cooling_register(np,
> > +				policy->related_cpus,
> > +				capacitance,
> > +				mtk_cpufreq_get_static);
> > +
> > +			if (IS_ERR(info->cdev)) {
> > +				dev_err(info->cpu_dev,
> > +					"cpufreq without cdev: %ld\n",
> > +					PTR_ERR(info->cdev));
> > +					info->cdev = NULL;
> > +			}
> >  
> > -			info->cdev = NULL;
> >  		}
> >  	}
> >  
> > @@ -460,7 +594,9 @@ static int mtk_cpufreq_exit(struct cpufreq_policy *policy)
> >  {
> >  	struct mtk_cpu_dvfs_info *info = policy->driver_data;
> >  
> > -	cpufreq_cooling_unregister(info->cdev);
> > +	if (info->cdev)
> > +		cpufreq_cooling_unregister(info->cdev);
> > +
> >  	dev_pm_opp_free_cpufreq_table(info->cpu_dev, &policy->freq_table);
> >  	mtk_cpu_dvfs_info_release(info);
> >  	kfree(info);
> > -- 
> > 1.7.9.5
> > 
> > --
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