ipq806x: switch to generic cpufreq driver cpufreq-dt

This fixes ondemand frequency scaling and moves ipq806x onto upstream driver

Also switching to ondemand frequency scaling as it is fixed now

Signed-off-by: Pavel Kubelun <be.dissent@gmail.com>

1 files changed, 184 insertions, 0 deletions

diff --git a/target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch b/target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch
new file mode 100644
index 0000000000..60ebe13b1b
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch
@@ -0,0 +1,184 @@
+From 175329015c8a0b480240da222822d2f8316f074d Mon Sep 17 00:00:00 2001
+From: Stephen Boyd <sboyd@codeaurora.org>
+Date: Mon, 1 Jun 2015 18:47:58 -0700
+Subject: 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>
+---
+ drivers/cpufreq/cpufreq-dt.c | 72 ++++++++++++++++++++++++++++++++++++++++----
+ 1 file changed, 66 insertions(+), 6 deletions(-)
+
+--- a/drivers/cpufreq/cpufreq-dt.c
++++ b/drivers/cpufreq/cpufreq-dt.c
+@@ -34,6 +34,9 @@ struct private_data {
+ 	struct regulator *cpu_reg;
+ 	struct thermal_cooling_device *cdev;
+ 	unsigned int voltage_tolerance; /* in percentage */
++	struct notifier_block opp_nb;
++	struct mutex lock;
++	unsigned long opp_freq;
+ };
+ 
+ static struct freq_attr *cpufreq_dt_attr[] = {
+@@ -42,6 +45,42 @@ static struct freq_attr *cpufreq_dt_attr
+ 	NULL,
+ };
+ 
++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 = priv->cpu_reg;
++	unsigned long volt, tol, freq;
++	int ret = 0;
++
++	switch (event) {
++		case OPP_EVENT_ADJUST_VOLTAGE:
++			volt = dev_pm_opp_get_voltage(opp);
++			freq = dev_pm_opp_get_freq(opp);
++			tol = volt * priv->voltage_tolerance / 100;
++
++			mutex_lock(&priv->lock);
++			if (freq == priv->opp_freq)
++				ret = regulator_set_voltage_tol(cpu_reg, volt,
++								tol);
++			mutex_unlock(&priv->lock);
++			if (ret) {
++				dev_err(cpu_dev,
++					"failed to scale voltage up: %d\n",
++					ret);
++				return ret;
++			}
++			break;
++		default:
++			break;
++	}
++
++	return 0;
++}
++
+ static int set_target(struct cpufreq_policy *policy, unsigned int index)
+ {
+ 	struct dev_pm_opp *opp;
+@@ -53,6 +92,7 @@ static int set_target(struct cpufreq_pol
+ 	unsigned long volt = 0, volt_old = 0, tol = 0;
+ 	unsigned int old_freq, new_freq;
+ 	long freq_Hz, freq_exact;
++	unsigned long opp_freq = 0;
+ 	int ret;
+ 
+ 	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
+@@ -63,8 +103,8 @@ static int set_target(struct cpufreq_pol
+ 	new_freq = freq_Hz / 1000;
+ 	old_freq = clk_get_rate(cpu_clk) / 1000;
+ 
++	mutex_lock(&priv->lock);
+ 	if (!IS_ERR(cpu_reg)) {
+-		unsigned long opp_freq;
+ 
+ 		rcu_read_lock();
+ 		opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
+@@ -72,7 +112,8 @@ static int set_target(struct cpufreq_pol
+ 			rcu_read_unlock();
+ 			dev_err(cpu_dev, "failed to find OPP for %ld\n",
+ 				freq_Hz);
+-			return PTR_ERR(opp);
++			ret = PTR_ERR(opp);
++			goto out;
+ 		}
+ 		volt = dev_pm_opp_get_voltage(opp);
+ 		opp_freq = dev_pm_opp_get_freq(opp);
+@@ -93,7 +134,7 @@ static int set_target(struct cpufreq_pol
+ 		if (ret) {
+ 			dev_err(cpu_dev, "failed to scale voltage up: %d\n",
+ 				ret);
+-			return ret;
++			goto out;
+ 		}
+ 	}
+ 
+@@ -102,7 +143,7 @@ static int set_target(struct cpufreq_pol
+ 		dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
+ 		if (!IS_ERR(cpu_reg) && volt_old > 0)
+ 			regulator_set_voltage_tol(cpu_reg, volt_old, tol);
+-		return ret;
++		goto out;
+ 	}
+ 
+ 	/* scaling down?  scale voltage after frequency */
+@@ -112,9 +153,12 @@ static int set_target(struct cpufreq_pol
+ 			dev_err(cpu_dev, "failed to scale voltage down: %d\n",
+ 				ret);
+ 			clk_set_rate(cpu_clk, old_freq * 1000);
++			goto out;
+ 		}
+ 	}
+-
++	priv->opp_freq = opp_freq;
++out:
++	mutex_unlock(&priv->lock);
+ 	return ret;
+ }
+ 
+@@ -201,6 +245,7 @@ static int cpufreq_init(struct cpufreq_p
+ 	unsigned int transition_latency;
+ 	bool need_update = false;
+ 	int ret;
++	struct srcu_notifier_head *opp_srcu_head;
+ 
+ 	ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
+ 	if (ret) {
+@@ -277,6 +322,19 @@ static int cpufreq_init(struct cpufreq_p
+ 		goto out_free_opp;
+ 	}
+ 
++	mutex_init(&priv->lock);
++
++	opp_srcu_head = dev_pm_opp_get_notifier(cpu_dev);
++	if (IS_ERR(opp_srcu_head)) {
++		ret = PTR_ERR(opp_srcu_head);
++		goto out_free_priv;
++	}
++
++	priv->opp_nb.notifier_call = opp_notifier;
++	ret = srcu_notifier_chain_register(opp_srcu_head, &priv->opp_nb);
++	if (ret)
++		goto out_free_priv;
++
+ 	of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
+ 
+ 	if (!transition_latency)
+@@ -326,7 +384,7 @@ static int cpufreq_init(struct cpufreq_p
+ 	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
+ 	if (ret) {
+ 		pr_err("failed to init cpufreq table: %d\n", ret);
+-		goto out_free_priv;
++		goto out_unregister_nb;
+ 	}
+ 
+ 	priv->cpu_dev = cpu_dev;
+@@ -365,6 +423,8 @@ static int cpufreq_init(struct cpufreq_p
+ 
+ out_free_cpufreq_table:
+ 	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
++out_unregister_nb:
++	srcu_notifier_chain_unregister(opp_srcu_head, &priv->opp_nb);
+ out_free_priv:
+ 	kfree(priv);
+ out_free_opp: