diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq-dt.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq-dt.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c new file mode 100644 index 000000000000..e00265066a75 --- /dev/null +++ b/drivers/cpufreq/cpufreq-dt.c @@ -0,0 +1,363 @@ +/* + * Copyright (C) 2012 Freescale Semiconductor, Inc. + * + * Copyright (C) 2014 Linaro. + * Viresh Kumar <viresh.kumar@linaro.org> + * + * The OPP code in function set_target() is reused from + * drivers/cpufreq/omap-cpufreq.c + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/clk.h> +#include <linux/cpu.h> +#include <linux/cpu_cooling.h> +#include <linux/cpufreq.h> +#include <linux/cpumask.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/pm_opp.h> +#include <linux/platform_device.h> +#include <linux/regulator/consumer.h> +#include <linux/slab.h> +#include <linux/thermal.h> + +struct private_data { + struct device *cpu_dev; + struct regulator *cpu_reg; + struct thermal_cooling_device *cdev; + unsigned int voltage_tolerance; /* in percentage */ +}; + +static int 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; + int ret; + + freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000); + if (freq_Hz <= 0) + freq_Hz = freq_table[index].frequency * 1000; + + freq_exact = freq_Hz; + new_freq = freq_Hz / 1000; + old_freq = clk_get_rate(cpu_clk) / 1000; + + if (!IS_ERR(cpu_reg)) { + rcu_read_lock(); + opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz); + if (IS_ERR(opp)) { + rcu_read_unlock(); + dev_err(cpu_dev, "failed to find OPP for %ld\n", + freq_Hz); + return PTR_ERR(opp); + } + volt = dev_pm_opp_get_voltage(opp); + rcu_read_unlock(); + tol = volt * priv->voltage_tolerance / 100; + volt_old = regulator_get_voltage(cpu_reg); + } + + dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n", + old_freq / 1000, volt_old ? volt_old / 1000 : -1, + new_freq / 1000, volt ? volt / 1000 : -1); + + /* scaling up? scale voltage before frequency */ + if (!IS_ERR(cpu_reg) && new_freq > old_freq) { + ret = regulator_set_voltage_tol(cpu_reg, volt, tol); + if (ret) { + dev_err(cpu_dev, "failed to scale voltage up: %d\n", + ret); + return ret; + } + } + + ret = clk_set_rate(cpu_clk, freq_exact); + if (ret) { + dev_err(cpu_dev, "failed to set clock rate: %d\n", ret); + if (!IS_ERR(cpu_reg)) + regulator_set_voltage_tol(cpu_reg, volt_old, tol); + return ret; + } + + /* scaling down? scale voltage after frequency */ + if (!IS_ERR(cpu_reg) && new_freq < old_freq) { + ret = regulator_set_voltage_tol(cpu_reg, volt, tol); + if (ret) { + dev_err(cpu_dev, "failed to scale voltage down: %d\n", + ret); + clk_set_rate(cpu_clk, old_freq * 1000); + } + } + + return ret; +} + +static int allocate_resources(int cpu, struct device **cdev, + struct regulator **creg, struct clk **cclk) +{ + struct device *cpu_dev; + struct regulator *cpu_reg; + struct clk *cpu_clk; + int ret = 0; + char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg; + + cpu_dev = get_cpu_device(cpu); + if (!cpu_dev) { + pr_err("failed to get cpu%d device\n", cpu); + return -ENODEV; + } + + /* Try "cpu0" for older DTs */ + if (!cpu) + reg = reg_cpu0; + else + reg = reg_cpu; + +try_again: + cpu_reg = regulator_get_optional(cpu_dev, reg); + if (IS_ERR(cpu_reg)) { + /* + * If cpu's regulator supply node is present, but regulator is + * not yet registered, we should try defering probe. + */ + if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) { + dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n", + cpu); + return -EPROBE_DEFER; + } + + /* Try with "cpu-supply" */ + if (reg == reg_cpu0) { + reg = reg_cpu; + goto try_again; + } + + dev_warn(cpu_dev, "failed to get cpu%d regulator: %ld\n", + cpu, PTR_ERR(cpu_reg)); + } + + 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); + + /* + * If cpu's clk node is present, but clock is not yet + * registered, we should try defering probe. + */ + if (ret == -EPROBE_DEFER) + dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu); + else + dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", ret, + cpu); + } else { + *cdev = cpu_dev; + *creg = cpu_reg; + *cclk = cpu_clk; + } + + return ret; +} + +static int 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; + + ret = allocate_resources(policy->cpu, &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 */ + of_init_opp_table(cpu_dev); + + 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_node; + } + + 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; + + if (!IS_ERR(cpu_reg)) { + struct dev_pm_opp *opp; + unsigned long min_uV, max_uV; + int i; + + /* + * OPP is maintained in order of increasing frequency, and + * freq_table initialised from OPP is therefore sorted in the + * same order. + */ + for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) + ; + rcu_read_lock(); + opp = dev_pm_opp_find_freq_exact(cpu_dev, + freq_table[0].frequency * 1000, true); + min_uV = dev_pm_opp_get_voltage(opp); + opp = dev_pm_opp_find_freq_exact(cpu_dev, + freq_table[i-1].frequency * 1000, true); + max_uV = dev_pm_opp_get_voltage(opp); + rcu_read_unlock(); + ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV); + if (ret > 0) + transition_latency += ret * 1000; + } + + /* + * For now, just loading the cooling device; + * thermal DT code takes care of matching them. + */ + if (of_find_property(np, "#cooling-cells", NULL)) { + cdev = of_cpufreq_cooling_register(np, cpu_present_mask); + if (IS_ERR(cdev)) + 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_node: + of_node_put(np); +out_put_reg_clk: + clk_put(cpu_clk); + if (!IS_ERR(cpu_reg)) + regulator_put(cpu_reg); + + return ret; +} + +static int 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 dt_cpufreq_driver = { + .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK, + .verify = cpufreq_generic_frequency_table_verify, + .target_index = set_target, + .get = cpufreq_generic_get, + .init = cpufreq_init, + .exit = cpufreq_exit, + .name = "cpufreq-dt", + .attr = cpufreq_generic_attr, +}; + +static int dt_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(0, &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(&dt_cpufreq_driver); + if (ret) + dev_err(cpu_dev, "failed register driver: %d\n", ret); + + return ret; +} + +static int dt_cpufreq_remove(struct platform_device *pdev) +{ + cpufreq_unregister_driver(&dt_cpufreq_driver); + return 0; +} + +static struct platform_driver dt_cpufreq_platdrv = { + .driver = { + .name = "cpufreq-dt", + .owner = THIS_MODULE, + }, + .probe = dt_cpufreq_probe, + .remove = dt_cpufreq_remove, +}; +module_platform_driver(dt_cpufreq_platdrv); + +MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); +MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); +MODULE_DESCRIPTION("Generic cpufreq driver"); +MODULE_LICENSE("GPL"); |