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Commit d2f31f1d authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
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cpufreq: cpu0: Move per-cluster initialization code to ->init() 



Currently this driver only support platforms on which all CPUs share clock &
voltage lines and there is requirement to support platforms which have separate
clock & voltage lines for CPUs, like Qualcomm's Krait and ARM's big LITTLE.

Each group of CPUs sharing clock/voltage lines are represented by 'struct
cpufreq_policy' in cpufreq framework. And core calls ->init() once for each
policy.

Currently we do all initialization/allocation from probe() which wouldn't work
for above scenario. To make it work for these platforms, the first step is to
move all initialization/allocation to ->init() and add ->exit() to do the
reverse of it.

Also, remove all global variables and allocate space for them at runtime.

This patch creates 'struct private_data' for keeping all such information and
a pointer to that would be stored in policy->driver_data.

The changed probe() routine now tries to see if regulator/clocks are available
or we need to defer probe. In case they are available, it registers cpufreq
driver. Otherwise, returns with -EPROBE_DEFER.

We still *don't* support platforms with separate clock/voltage lines for CPUs.
This would be done in a separate patch later.

Tested-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent fbd48ca5

drivers/cpufreq/cpufreq-cpu0.c

+136 −53
Original line number Diff line number Diff line
@@ -28,18 +28,21 @@ 
#include <linux/slab.h>

#include <linux/thermal.h>



static unsigned int transition_latency;

static unsigned int voltage_tolerance; /* in percentage */



static struct device *cpu_dev;

static struct clk *cpu_clk;

static struct regulator *cpu_reg;

static struct cpufreq_frequency_table *freq_table;

static struct thermal_cooling_device *cdev;

struct private_data {

	struct device *cpu_dev;

	struct regulator *cpu_reg;

	struct thermal_cooling_device *cdev;

	unsigned int voltage_tolerance; /* in percentage */

};



static int cpu0_set_target(struct cpufreq_policy *policy, unsigned int index)

{

	struct dev_pm_opp *opp;

	struct cpufreq_frequency_table *freq_table = policy->freq_table;

	struct clk *cpu_clk = policy->clk;

	struct private_data *priv = policy->driver_data;

	struct device *cpu_dev = priv->cpu_dev;

	struct regulator *cpu_reg = priv->cpu_reg;

	unsigned long volt = 0, volt_old = 0, tol = 0;

	unsigned int old_freq, new_freq;

	long freq_Hz, freq_exact;
@@ -64,7 +67,7 @@ static int cpu0_set_target(struct cpufreq_policy *policy, unsigned int index) 
		}

		volt = dev_pm_opp_get_voltage(opp);

		rcu_read_unlock();

		tol = volt * voltage_tolerance / 100;

		tol = volt * priv->voltage_tolerance / 100;

		volt_old = regulator_get_voltage(cpu_reg);

	}
@@ -103,26 +106,13 @@ static int cpu0_set_target(struct cpufreq_policy *policy, unsigned int index) 
	return ret;

}



static int cpu0_cpufreq_init(struct cpufreq_policy *policy)

static int allocate_resources(struct device **cdev,

			      struct regulator **creg, struct clk **cclk)

{

	policy->clk = cpu_clk;

	return cpufreq_generic_init(policy, freq_table, transition_latency);

}



static struct cpufreq_driver cpu0_cpufreq_driver = {

	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,

	.verify = cpufreq_generic_frequency_table_verify,

	.target_index = cpu0_set_target,

	.get = cpufreq_generic_get,

	.init = cpu0_cpufreq_init,

	.name = "generic_cpu0",

	.attr = cpufreq_generic_attr,

};



static int cpu0_cpufreq_probe(struct platform_device *pdev)

{

	struct device_node *np;

	int ret;

	struct device *cpu_dev;

	struct regulator *cpu_reg;

	struct clk *cpu_clk;

	int ret = 0;



	cpu_dev = get_cpu_device(0);

	if (!cpu_dev) {
@@ -130,12 +120,6 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev) 
		return -ENODEV;

	}



	np = of_node_get(cpu_dev->of_node);

	if (!np) {

		dev_err(cpu_dev, "failed to find cpu0 node\n");

		return -ENOENT;

	}



	cpu_reg = regulator_get_optional(cpu_dev, "cpu0");

	if (IS_ERR(cpu_reg)) {

		/*
@@ -144,8 +128,7 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev) 
		 */

		if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {

			dev_dbg(cpu_dev, "cpu0 regulator not ready, retry\n");

			ret = -EPROBE_DEFER;

			goto out_put_node;

			return -EPROBE_DEFER;

		}

		dev_warn(cpu_dev, "failed to get cpu0 regulator: %ld\n",

			 PTR_ERR(cpu_reg));
@@ -153,6 +136,10 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev) 


	cpu_clk = clk_get(cpu_dev, NULL);

	if (IS_ERR(cpu_clk)) {

		/* put regulator */

		if (!IS_ERR(cpu_reg))

			regulator_put(cpu_reg);



		ret = PTR_ERR(cpu_clk);



		/*
@@ -163,8 +150,39 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev) 
			dev_dbg(cpu_dev, "cpu0 clock not ready, retry\n");

		else

			dev_err(cpu_dev, "failed to get cpu0 clock: %d\n", ret);

	} else {

		*cdev = cpu_dev;

		*creg = cpu_reg;

		*cclk = cpu_clk;

	}



		goto out_put_reg;

	return ret;

}



static int cpu0_cpufreq_init(struct cpufreq_policy *policy)

{

	struct cpufreq_frequency_table *freq_table;

	struct thermal_cooling_device *cdev;

	struct device_node *np;

	struct private_data *priv;

	struct device *cpu_dev;

	struct regulator *cpu_reg;

	struct clk *cpu_clk;

	unsigned int transition_latency;

	int ret;



	/* We only support cpu0 currently */

	ret = allocate_resources(&cpu_dev, &cpu_reg, &cpu_clk);

	if (ret) {

		pr_err("%s: Failed to allocate resources\n: %d", __func__, ret);

		return ret;

	}



	np = of_node_get(cpu_dev->of_node);

	if (!np) {

		dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);

		ret = -ENOENT;

		goto out_put_reg_clk;

	}



	/* OPPs might be populated at runtime, don't check for error here */
@@ -173,10 +191,16 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev) 
	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_put_clk;

		goto out_put_node;

	}



	of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);

	if (!priv) {

		ret = -ENOMEM;

		goto out_free_table;

	}



	of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);



	if (of_property_read_u32(np, "clock-latency", &transition_latency))

		transition_latency = CPUFREQ_ETERNAL;
@@ -206,12 +230,6 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev) 
			transition_latency += ret * 1000;

	}



	ret = cpufreq_register_driver(&cpu0_cpufreq_driver);

	if (ret) {

		dev_err(cpu_dev, "failed to register driver: %d\n", ret);

		goto out_free_table;

	}



	/*

	 * For now, just loading the cooling device;

	 * thermal DT code takes care of matching them.
@@ -222,29 +240,94 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev) 
			dev_err(cpu_dev,

				"running cpufreq without cooling device: %ld\n",

				PTR_ERR(cdev));

		else

			priv->cdev = cdev;

	}



	of_node_put(np);



	priv->cpu_dev = cpu_dev;

	priv->cpu_reg = cpu_reg;

	policy->driver_data = priv;



	policy->clk = cpu_clk;

	ret = cpufreq_generic_init(policy, freq_table, transition_latency);

	if (ret)

		goto out_cooling_unregister;



	return 0;



out_cooling_unregister:

	cpufreq_cooling_unregister(priv->cdev);

	kfree(priv);

out_free_table:

	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);

out_put_clk:

out_put_node:

	of_node_put(np);

out_put_reg_clk:

	clk_put(cpu_clk);

out_put_reg:

	if (!IS_ERR(cpu_reg))

		regulator_put(cpu_reg);

out_put_node:

	of_node_put(np);



	return ret;

}



static int cpu0_cpufreq_exit(struct cpufreq_policy *policy)

{

	struct private_data *priv = policy->driver_data;



	cpufreq_cooling_unregister(priv->cdev);

	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);

	clk_put(policy->clk);

	if (!IS_ERR(priv->cpu_reg))

		regulator_put(priv->cpu_reg);

	kfree(priv);



	return 0;

}



static struct cpufreq_driver cpu0_cpufreq_driver = {

	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,

	.verify = cpufreq_generic_frequency_table_verify,

	.target_index = cpu0_set_target,

	.get = cpufreq_generic_get,

	.init = cpu0_cpufreq_init,

	.exit = cpu0_cpufreq_exit,

	.name = "generic_cpu0",

	.attr = cpufreq_generic_attr,

};



static int cpu0_cpufreq_probe(struct platform_device *pdev)

{

	struct device *cpu_dev;

	struct regulator *cpu_reg;

	struct clk *cpu_clk;

	int ret;



	/*

	 * All per-cluster (CPUs sharing clock/voltages) initialization is done

	 * from ->init(). In probe(), we just need to make sure that clk and

	 * regulators are available. Else defer probe and retry.

	 *

	 * FIXME: Is checking this only for CPU0 sufficient ?

	 */

	ret = allocate_resources(&cpu_dev, &cpu_reg, &cpu_clk);

	if (ret)

		return ret;



	clk_put(cpu_clk);

	if (!IS_ERR(cpu_reg))

		regulator_put(cpu_reg);



	ret = cpufreq_register_driver(&cpu0_cpufreq_driver);

	if (ret)

		dev_err(cpu_dev, "failed register driver: %d\n", ret);



	return ret;

}



static int cpu0_cpufreq_remove(struct platform_device *pdev)

{

	cpufreq_cooling_unregister(cdev);

	cpufreq_unregister_driver(&cpu0_cpufreq_driver);

	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);



	return 0;

}