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@linaro.org --- 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; }