OpenWrt – Rev 3
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From 10577f74c35bd395951d1b2382c8d821089b5745 Mon Sep 17 00:00:00 2001
From: Stephen Boyd <sboyd@codeaurora.org>
Date: Fri, 18 Sep 2015 17:52:08 -0700
Subject: [PATCH 54/69] cpufreq-dt: Handle OPP voltage adjust events
On some SoCs the Adaptive Voltage Scaling (AVS) technique is
employed to optimize the operating voltage of a device. At a
given frequency, the hardware monitors dynamic factors and either
makes a suggestion for how much to adjust a voltage for the
current frequency, or it automatically adjusts the voltage
without software intervention.
In the former case, an AVS driver will call
dev_pm_opp_modify_voltage() and update the voltage for the
particular OPP the CPUs are using. Add an OPP notifier to
cpufreq-dt so that we can adjust the voltage of the CPU when AVS
updates the OPP.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
---
drivers/cpufreq/cpufreq-dt.c | 68 ++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 65 insertions(+), 3 deletions(-)
--- a/drivers/cpufreq/cpufreq-dt.c
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -32,6 +32,9 @@ struct private_data {
struct device *cpu_dev;
struct thermal_cooling_device *cdev;
const char *reg_name;
+ struct notifier_block opp_nb;
+ struct mutex lock;
+ unsigned long opp_freq;
};
static struct freq_attr *cpufreq_dt_attr[] = {
@@ -43,9 +46,16 @@ static struct freq_attr *cpufreq_dt_attr
static int set_target(struct cpufreq_policy *policy, unsigned int index)
{
struct private_data *priv = policy->driver_data;
+ int ret;
+ unsigned long target_freq = policy->freq_table[index].frequency * 1000;
+
+ mutex_lock(&priv->lock);
+ ret = dev_pm_opp_set_rate(priv->cpu_dev, target_freq);
+ if (!ret)
+ priv->opp_freq = target_freq;
+ mutex_unlock(&priv->lock);
- return dev_pm_opp_set_rate(priv->cpu_dev,
- policy->freq_table[index].frequency * 1000);
+ return ret;
}
/*
@@ -86,6 +96,39 @@ node_put:
return name;
}
+static int opp_notifier(struct notifier_block *nb, unsigned long event,
+ void *data)
+{
+ struct dev_pm_opp *opp = data;
+ struct private_data *priv = container_of(nb, struct private_data,
+ opp_nb);
+ struct device *cpu_dev = priv->cpu_dev;
+ struct regulator *cpu_reg;
+ unsigned long volt, freq;
+ int ret = 0;
+
+ if (event == OPP_EVENT_ADJUST_VOLTAGE) {
+ cpu_reg = dev_pm_opp_get_regulator(cpu_dev);
+ if (IS_ERR(cpu_reg)) {
+ ret = PTR_ERR(cpu_reg);
+ goto out;
+ }
+ volt = dev_pm_opp_get_voltage(opp);
+ freq = dev_pm_opp_get_freq(opp);
+
+ mutex_lock(&priv->lock);
+ if (freq == priv->opp_freq) {
+ ret = regulator_set_voltage_triplet(cpu_reg, volt, volt, volt);
+ }
+ mutex_unlock(&priv->lock);
+ if (ret)
+ dev_err(cpu_dev, "failed to scale voltage: %d\n", ret);
+ }
+
+out:
+ return notifier_from_errno(ret);
+}
+
static int resources_available(void)
{
struct device *cpu_dev;
@@ -152,6 +195,7 @@ static int cpufreq_init(struct cpufreq_p
bool fallback = false;
const char *name;
int ret;
+ struct srcu_notifier_head *opp_srcu_head;
cpu_dev = get_cpu_device(policy->cpu);
if (!cpu_dev) {
@@ -241,13 +285,16 @@ static int cpufreq_init(struct cpufreq_p
goto out_free_opp;
}
+ mutex_init(&priv->lock);
+ dev_pm_opp_register_notifier(cpu_dev, &priv->opp_nb);
+
priv->reg_name = name;
priv->opp_table = opp_table;
ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
if (ret) {
dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
- goto out_free_priv;
+ goto out_unregister_nb;
}
priv->cpu_dev = cpu_dev;
@@ -283,6 +330,8 @@ static int cpufreq_init(struct cpufreq_p
out_free_cpufreq_table:
dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+out_unregister_nb:
+ dev_pm_opp_unregister_notifier(cpu_dev, &priv->opp_nb);
out_free_priv:
kfree(priv);
out_free_opp: