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

Eduardo Valentin
2015-11-04T19:40:06Z

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@mediatek.com>
> ---
> 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,

> 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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