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.
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/cpufreq/cpufreq-cpu0.c | 189 +++++++++++++++++++++++++++++------------
1 file changed, 136 insertions(+), 53 deletions(-)
diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index 2b7b0ea..15b8e7a 100644
--- 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_err(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);
+
/*
* If cpu's clk node is present, but clock is not yet
* registered, we should try defering probe.
@@ -164,7 +151,39 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
ret = PTR_ERR(cpu_clk);
dev_err(cpu_dev, "failed to get cpu0 clock: %d\n", ret);
}
- goto out_put_reg;
+ } 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;
+ }
+
+ 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 +192,16 @@ 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 +231,6 @@ 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.
@@ -223,28 +242,92 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
"running cpufreq without cooling device: %ld\n",
PTR_ERR(cdev));
}
-
of_node_put(np);
+
+ priv->cdev = cdev;
+ 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;
}
--
2.0.0.rc2
--
To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
