--- /dev/null
+/*
+ * 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/cpufreq-dt.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)) {
+ unsigned long opp_freq;
+
+ 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);
+ opp_freq = dev_pm_opp_get_freq(opp);
+ rcu_read_unlock();
+ tol = volt * priv->voltage_tolerance / 100;
+ volt_old = regulator_get_voltage(cpu_reg);
+ dev_dbg(cpu_dev, "Found OPP: %ld kHz, %ld uV\n",
+ opp_freq / 1000, volt);
+ }
+
+ dev_dbg(cpu_dev, "%u MHz, %ld mV --> %u MHz, %ld mV\n",
+ old_freq / 1000, (volt_old > 0) ? 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) && volt_old > 0)
+ 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_dbg(cpu_dev, "no regulator for cpu%d: %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", cpu,
+ ret);
+ } else {
+ *cdev = cpu_dev;
+ *creg = cpu_reg;
+ *cclk = cpu_clk;
+ }
+
+ return ret;
+}
+
+static int cpufreq_init(struct cpufreq_policy *policy)
+{
+ struct cpufreq_dt_platform_data *pd;
+ struct cpufreq_frequency_table *freq_table;
+ struct device_node *np;
+ struct private_data *priv;
+ struct device *cpu_dev;
+ struct regulator *cpu_reg;
+ struct clk *cpu_clk;
+ unsigned long min_uV = ~0, max_uV = 0;
+ 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: %d\n", __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);
+
+ /*
+ * But we need OPP table to function so if it is not there let's
+ * give platform code chance to provide it for us.
+ */
+ ret = dev_pm_opp_get_opp_count(cpu_dev);
+ if (ret <= 0) {
+ pr_debug("OPP table is not ready, deferring probe\n");
+ ret = -EPROBE_DEFER;
+ goto out_free_opp;
+ }
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv) {
+ ret = -ENOMEM;
+ goto out_free_opp;
+ }
+
+ 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)) {
+ unsigned long opp_freq = 0;
+
+ /*
+ * Disable any OPPs where the connected regulator isn't able to
+ * provide the specified voltage and record minimum and maximum
+ * voltage levels.
+ */
+ while (1) {
+ struct dev_pm_opp *opp;
+ unsigned long opp_uV, tol_uV;
+
+ rcu_read_lock();
+ opp = dev_pm_opp_find_freq_ceil(cpu_dev, &opp_freq);
+ if (IS_ERR(opp)) {
+ rcu_read_unlock();
+ break;
+ }
+ opp_uV = dev_pm_opp_get_voltage(opp);
+ rcu_read_unlock();
+
+ tol_uV = opp_uV * priv->voltage_tolerance / 100;
+ if (regulator_is_supported_voltage(cpu_reg, opp_uV,
+ opp_uV + tol_uV)) {
+ if (opp_uV < min_uV)
+ min_uV = opp_uV;
+ if (opp_uV > max_uV)
+ max_uV = opp_uV;
+ } else {
+ dev_pm_opp_disable(cpu_dev, opp_freq);
+ }
+
+ opp_freq++;
+ }
+
+ ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
+ if (ret > 0)
+ transition_latency += ret * 1000;
+ }
+
+ ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
+ if (ret) {
+ pr_err("failed to init cpufreq table: %d\n", ret);
+ goto out_free_priv;
+ }
+
+ priv->cpu_dev = cpu_dev;
+ priv->cpu_reg = cpu_reg;
+ policy->driver_data = priv;
+
+ policy->clk = cpu_clk;
+ ret = cpufreq_table_validate_and_show(policy, freq_table);
+ if (ret) {
+ dev_err(cpu_dev, "%s: invalid frequency table: %d\n", __func__,
+ ret);
+ goto out_free_cpufreq_table;
+ }
+
+ policy->cpuinfo.transition_latency = transition_latency;
+
+ pd = cpufreq_get_driver_data();
+ if (!pd || !pd->independent_clocks)
+ cpumask_setall(policy->cpus);
+
+ of_node_put(np);
+
+ return 0;
+
+out_free_cpufreq_table:
+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+out_free_priv:
+ kfree(priv);
+out_free_opp:
+ of_free_opp_table(cpu_dev);
+ 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);
+ of_free_opp_table(priv->cpu_dev);
+ clk_put(policy->clk);
+ if (!IS_ERR(priv->cpu_reg))
+ regulator_put(priv->cpu_reg);
+ kfree(priv);
+
+ return 0;
+}
+
+static void cpufreq_ready(struct cpufreq_policy *policy)
+{
+ struct private_data *priv = policy->driver_data;
+ struct device_node *np = of_node_get(priv->cpu_dev->of_node);
+
+ if (WARN_ON(!np))
+ return;
+
+ /*
+ * For now, just loading the cooling device;
+ * thermal DT code takes care of matching them.
+ */
+ if (of_find_property(np, "#cooling-cells", NULL)) {
+ priv->cdev = of_cpufreq_cooling_register(np,
+ policy->related_cpus);
+ if (IS_ERR(priv->cdev)) {
+ dev_err(priv->cpu_dev,
+ "running cpufreq without cooling device: %ld\n",
+ PTR_ERR(priv->cdev));
+
+ priv->cdev = NULL;
+ }
+ }
+
+ of_node_put(np);
+}
+
+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,
+ .ready = cpufreq_ready,
+ .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);
+
+ dt_cpufreq_driver.driver_data = dev_get_platdata(&pdev->dev);
+
+ 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",
+ },
+ .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");
Code Review / kvmfornfv.git / blobdiff