arm64: spinlock: serialise spin_unlock_wait against concurrent lockers

[linux/fpc-iii.git] / drivers / cpufreq / cpufreq-dt.c

/*
 * 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 struct freq_attr *cpufreq_dt_attr[] = {
        &cpufreq_freq_attr_scaling_available_freqs,
        NULL,   /* Extra space for boost-attr if required */
        NULL,
};

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_frequency_table *freq_table;
        struct device_node *np;
        struct private_data *priv;
        struct device *cpu_dev;
        struct regulator *cpu_reg;
        struct clk *cpu_clk;
        struct dev_pm_opp *suspend_opp;
        unsigned long min_uV = ~0, max_uV = 0;
        unsigned int transition_latency;
        bool need_update = false;
        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;
        }

        /* Get OPP-sharing information from "operating-points-v2" bindings */
        ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, policy->cpus);
        if (ret) {
                /*
                 * operating-points-v2 not supported, fallback to old method of
                 * finding shared-OPPs for backward compatibility.
                 */
                if (ret == -ENOENT)
                        need_update = true;
                else
                        goto out_node_put;
        }

        /*
         * Initialize OPP tables for all policy->cpus. They will be shared by
         * all CPUs which have marked their CPUs shared with OPP bindings.
         *
         * For platforms not using operating-points-v2 bindings, we do this
         * before updating policy->cpus. Otherwise, we will end up creating
         * duplicate OPPs for policy->cpus.
         *
         * OPPs might be populated at runtime, don't check for error here
         */
        dev_pm_opp_of_cpumask_add_table(policy->cpus);

        /*
         * 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;
        }

        if (need_update) {
                struct cpufreq_dt_platform_data *pd = cpufreq_get_driver_data();

                if (!pd || !pd->independent_clocks)
                        cpumask_setall(policy->cpus);

                /*
                 * OPP tables are initialized only for policy->cpu, do it for
                 * others as well.
                 */
                ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
                if (ret)
                        dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
                                __func__, ret);

                of_property_read_u32(np, "clock-latency", &transition_latency);
        } else {
                transition_latency = dev_pm_opp_get_max_clock_latency(cpu_dev);
        }

        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 (!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 - tol_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;

        rcu_read_lock();
        suspend_opp = dev_pm_opp_get_suspend_opp(cpu_dev);
        if (suspend_opp)
                policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
        rcu_read_unlock();

        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;
        }

        /* Support turbo/boost mode */
        if (policy_has_boost_freq(policy)) {
                /* This gets disabled by core on driver unregister */
                ret = cpufreq_enable_boost_support();
                if (ret)
                        goto out_free_cpufreq_table;
                cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
        }

        policy->cpuinfo.transition_latency = transition_latency;

        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:
        dev_pm_opp_of_cpumask_remove_table(policy->cpus);
out_node_put:
        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);
        dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
        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_dt_attr,
        .suspend = cpufreq_generic_suspend,
};

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_ALIAS("platform:cpufreq-dt");
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Generic cpufreq driver");
MODULE_LICENSE("GPL");