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: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index 741ff22..03e352b 100644 (file)
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/drivers/cpufreq/cpufreq-cpu0.c
@@ -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)
-{
-       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)
+static int allocate_resources(struct device **cdev,
+                             struct regulator **creg, struct clk **cclk)
 {
-       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;
+       }
+
+       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;
+       }
 
-               goto out_put_reg;
+       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;
+       }
+
+       priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+       if (!priv) {
+               ret = -ENOMEM;
+               goto out_free_table;
        }
 
-       of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);
+       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;
 }