drivers/cpufreq/tegra-cpufreq.c - chromiumos/third_party/kernel - Git at Google

 /*
  * Copyright (C) 2010 Google, Inc.
  * Copyright (c) 2013, NVIDIA Corporation.
  *
  * Author:
  *	Colin Cross <ccross@google.com>
  *	Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
  * may be copied, distributed, and modified under those terms.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  */

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/suspend.h>
 #include <linux/cpu.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>

 #include "tegra-cpufreq.h"

 #define MAX_CPUS	4

 static struct tegra_cpufreq_data *tegra_data;
 static const struct tegra_cpufreq_config *soc_config;

 static unsigned long target_cpu_speed[MAX_CPUS];
 static DEFINE_MUTEX(tegra_cpu_lock);
 static bool is_suspended;

 static int tegra_verify_speed(struct cpufreq_policy *policy)
 {
 	return cpufreq_frequency_table_verify(policy, tegra_data->freq_table);
 }

 static unsigned int tegra_getspeed(unsigned int cpu)
 {
 	unsigned long rate;
 	int i;

 	rate = clk_get_rate(tegra_data->cpu_clk) / 1000;
 	/*
 	 * Round to the neareset frequency.  The actual frequency generated
 	 * by the CPU clock may differ slightly from the rate in the table.
 	 */
 	for (i = 0;
 	     tegra_data->freq_table[i + 1].frequency != CPUFREQ_TABLE_END;
 	     i++) {
 		if (rate < (tegra_data->freq_table[i].frequency +
 			    tegra_data->freq_table[i + 1].frequency) / 2)
 			return tegra_data->freq_table[i].frequency;
 	}

 	return tegra_data->freq_table[i].frequency;
 }

 static int tegra_update_cpu_speed(struct cpufreq_policy *policy,
 		unsigned long rate)
 {
 	int ret = 0;
 	struct cpufreq_freqs freqs;

 	freqs.old = tegra_getspeed(0);
 	freqs.new = rate;

 	if (freqs.old == freqs.new)
 		return ret;

 	/*
 	 * Vote on memory bus frequency based on cpu frequency
 	 * If cpu frequency is increasing, boost memory bandwidth first
 	 */
 	if (soc_config->emc_clk_set_rate && freqs.new > freqs.old)
 		soc_config->emc_clk_set_rate(rate);

 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

 #ifdef CONFIG_CPU_FREQ_DEBUG
 	printk(KERN_DEBUG "cpufreq-tegra: transition: %u --> %u\n",
 	       freqs.old, freqs.new);
 #endif

 	ret = soc_config->cpu_clk_set_rate(freqs.new * 1000);
 	if (ret) {
 		pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
 			freqs.new);
 		freqs.new = freqs.old;
 	}

 	/*
 	 * Vote on memory bus frequency based on cpu frequency
 	 * If cpu frequency is decreasing, lower memory bandwidth later
 	 */
 	if (soc_config->emc_clk_set_rate && freqs.new < freqs.old)
 		soc_config->emc_clk_set_rate(rate);

 	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

 	return ret;
 }

 static unsigned long tegra_cpu_highest_speed(void)
 {
 	unsigned long rate = 0;
 	int i;

 	for_each_online_cpu(i)
 		rate = max(rate, target_cpu_speed[i]);
 	return rate;
 }

 static int tegra_target(struct cpufreq_policy *policy,
 		       unsigned int target_freq,
 		       unsigned int relation)
 {
 	struct cpufreq_frequency_table *freq_table = tegra_data->freq_table;
 	unsigned int idx;
 	unsigned int freq;
 	int ret = 0;

 	mutex_lock(&tegra_cpu_lock);

 	if (is_suspended) {
 		ret = -EBUSY;
 		goto out;
 	}

 	cpufreq_frequency_table_target(policy, freq_table, target_freq,
 		relation, &idx);

 	freq = freq_table[idx].frequency;

 	target_cpu_speed[policy->cpu] = freq;

 	ret = tegra_update_cpu_speed(policy, tegra_cpu_highest_speed());

 out:
 	mutex_unlock(&tegra_cpu_lock);
 	return ret;
 }

 static int tegra_pm_notify(struct notifier_block *nb, unsigned long event,
 	void *dummy)
 {
 	struct cpufreq_frequency_table *freq_table = tegra_data->freq_table;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(0);

 	mutex_lock(&tegra_cpu_lock);
 	if (event == PM_SUSPEND_PREPARE) {
 		is_suspended = true;
 		pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n",
 			freq_table[tegra_data->suspend_index].frequency);
 		tegra_update_cpu_speed(policy,
 			freq_table[tegra_data->suspend_index].frequency);
 		cpufreq_cpu_put(policy);
 	} else if (event == PM_POST_SUSPEND) {
 		is_suspended = false;
 		tegra_update_cpu_speed(policy, policy->max);
 		pr_info("Tegra cpufreq resume: restore frequency to %u kHz\n",
 				policy->max);
 		cpufreq_cpu_put(policy);
 	}
 	mutex_unlock(&tegra_cpu_lock);

 	return NOTIFY_OK;
 }

 static struct notifier_block tegra_cpu_pm_notifier = {
 	.notifier_call = tegra_pm_notify,
 };

 static int tegra_cpu_init(struct cpufreq_policy *policy)
 {
 	if (soc_config->cpufreq_clk_init)
 		soc_config->cpufreq_clk_init();

 	cpufreq_frequency_table_cpuinfo(policy, tegra_data->freq_table);
 	cpufreq_frequency_table_get_attr(tegra_data->freq_table, policy->cpu);
 	policy->cur = tegra_getspeed(policy->cpu);
 	target_cpu_speed[policy->cpu] = policy->cur;

 	/* FIXME: what's the actual transition time? */
 	policy->cpuinfo.transition_latency = 300 * 1000;

 	cpumask_copy(policy->cpus, cpu_possible_mask);

 	if (policy->cpu == 0)
 		register_pm_notifier(&tegra_cpu_pm_notifier);

 	return 0;
 }

 static int tegra_cpu_exit(struct cpufreq_policy *policy)
 {
 	cpufreq_frequency_table_cpuinfo(policy, tegra_data->freq_table);
 	if (soc_config->cpufreq_clk_exit)
 		soc_config->cpufreq_clk_exit();
 	return 0;
 }

 static struct freq_attr *tegra_cpufreq_attr[] = {
 	&cpufreq_freq_attr_scaling_available_freqs,
 	NULL,
 };

 static struct cpufreq_driver tegra_cpufreq_driver = {
 	.verify		= tegra_verify_speed,
 	.target		= tegra_target,
 	.get		= tegra_getspeed,
 	.init		= tegra_cpu_init,
 	.exit		= tegra_cpu_exit,
 	.name		= "tegra",
 	.attr		= tegra_cpufreq_attr,
 };

 static struct {
 	char *compat;
 	int (*init)(struct tegra_cpufreq_data *,
 			const struct tegra_cpufreq_config **);
 } tegra_init_funcs[] = {
 	{ "nvidia,tegra20", tegra20_cpufreq_init },
 	{ "nvidia,tegra124", tegra124_cpufreq_init },
 };

 static int tegra_cpufreq_probe(struct platform_device *pdev)
 {
 	int i;
 	int ret = -EINVAL;

 	tegra_data = devm_kzalloc(&pdev->dev,
 			sizeof(*tegra_data), GFP_KERNEL);
 	if (!tegra_data) {
 		ret = -ENOMEM;
 		goto out;
 	}

 	tegra_data->dev = &pdev->dev;

 	for (i = 0; i < ARRAY_SIZE(tegra_init_funcs); i++) {
 		if (of_machine_is_compatible(tegra_init_funcs[i].compat)) {
 			ret = tegra_init_funcs[i].init(tegra_data, &soc_config);
 			if (!ret)
 				break;
 			else
 				goto out;
 		}
 	}
 	if (i == ARRAY_SIZE(tegra_init_funcs))
 		goto out;

 	ret = cpufreq_register_driver(&tegra_cpufreq_driver);
 	if (ret) {
 		dev_err(tegra_data->dev,
 			"%s: failed to register cpufreq driver\n", __func__);
 		goto out;
 	}

 	return 0;
 out:
 	return ret;
 }

 static int tegra_cpufreq_remove(struct platform_device *pdev)
 {
 	cpufreq_unregister_driver(&tegra_cpufreq_driver);
 	return 0;
 }

 static struct platform_driver tegra_cpufreq_platdrv = {
 	.driver = {
 		.name	= "tegra-cpufreq",
 		.owner	= THIS_MODULE,
 	},
 	.probe		= tegra_cpufreq_probe,
 	.remove		= tegra_cpufreq_remove,
 };
 module_platform_driver(tegra_cpufreq_platdrv);

 int __init tegra_cpufreq_init(void)
 {
 	struct platform_device_info devinfo = { .name = "tegra-cpufreq", };

 	platform_device_register_full(&devinfo);

 	return 0;
 }
 EXPORT_SYMBOL(tegra_cpufreq_init);


 MODULE_AUTHOR("Colin Cross <ccross@android.com>");
 MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2010 Google, Inc.
	* Copyright (c) 2013, NVIDIA Corporation.
	*
	* Author:
	* Colin Cross <ccross@google.com>
	* Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation
	*
	* This software is licensed under the terms of the GNU General Public
	* License version 2, as published by the Free Software Foundation, and
	* may be copied, distributed, and modified under those terms.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/cpufreq.h>
	#include <linux/err.h>
	#include <linux/clk.h>
	#include <linux/suspend.h>
	#include <linux/cpu.h>
	#include <linux/platform_device.h>
	#include <linux/of.h>

	#include "tegra-cpufreq.h"

	#define MAX_CPUS 4

	static struct tegra_cpufreq_data *tegra_data;
	static const struct tegra_cpufreq_config *soc_config;

	static unsigned long target_cpu_speed[MAX_CPUS];
	static DEFINE_MUTEX(tegra_cpu_lock);
	static bool is_suspended;

	static int tegra_verify_speed(struct cpufreq_policy *policy)
	{
	return cpufreq_frequency_table_verify(policy, tegra_data->freq_table);
	}

	static unsigned int tegra_getspeed(unsigned int cpu)
	{
	unsigned long rate;
	int i;

	rate = clk_get_rate(tegra_data->cpu_clk) / 1000;
	/*
	* Round to the neareset frequency. The actual frequency generated
	* by the CPU clock may differ slightly from the rate in the table.
	*/
	for (i = 0;
	tegra_data->freq_table[i + 1].frequency != CPUFREQ_TABLE_END;
	i++) {
	if (rate < (tegra_data->freq_table[i].frequency +
	tegra_data->freq_table[i + 1].frequency) / 2)
	return tegra_data->freq_table[i].frequency;
	}

	return tegra_data->freq_table[i].frequency;
	}

	static int tegra_update_cpu_speed(struct cpufreq_policy *policy,
	unsigned long rate)
	{
	int ret = 0;
	struct cpufreq_freqs freqs;

	freqs.old = tegra_getspeed(0);
	freqs.new = rate;

	if (freqs.old == freqs.new)
	return ret;

	/*
	* Vote on memory bus frequency based on cpu frequency
	* If cpu frequency is increasing, boost memory bandwidth first
	*/
	if (soc_config->emc_clk_set_rate && freqs.new > freqs.old)
	soc_config->emc_clk_set_rate(rate);

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

	#ifdef CONFIG_CPU_FREQ_DEBUG
	printk(KERN_DEBUG "cpufreq-tegra: transition: %u --> %u\n",
	freqs.old, freqs.new);
	#endif

	ret = soc_config->cpu_clk_set_rate(freqs.new * 1000);
	if (ret) {
	pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
	freqs.new);
	freqs.new = freqs.old;
	}

	/*
	* Vote on memory bus frequency based on cpu frequency
	* If cpu frequency is decreasing, lower memory bandwidth later
	*/
	if (soc_config->emc_clk_set_rate && freqs.new < freqs.old)
	soc_config->emc_clk_set_rate(rate);

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

	return ret;
	}

	static unsigned long tegra_cpu_highest_speed(void)
	{
	unsigned long rate = 0;
	int i;

	for_each_online_cpu(i)
	rate = max(rate, target_cpu_speed[i]);
	return rate;
	}

	static int tegra_target(struct cpufreq_policy *policy,
	unsigned int target_freq,
	unsigned int relation)
	{
	struct cpufreq_frequency_table *freq_table = tegra_data->freq_table;
	unsigned int idx;
	unsigned int freq;
	int ret = 0;

	mutex_lock(&tegra_cpu_lock);

	if (is_suspended) {
	ret = -EBUSY;
	goto out;
	}

	cpufreq_frequency_table_target(policy, freq_table, target_freq,
	relation, &idx);

	freq = freq_table[idx].frequency;

	target_cpu_speed[policy->cpu] = freq;

	ret = tegra_update_cpu_speed(policy, tegra_cpu_highest_speed());

	out:
	mutex_unlock(&tegra_cpu_lock);
	return ret;
	}

	static int tegra_pm_notify(struct notifier_block *nb, unsigned long event,
	void *dummy)
	{
	struct cpufreq_frequency_table *freq_table = tegra_data->freq_table;
	struct cpufreq_policy *policy = cpufreq_cpu_get(0);

	mutex_lock(&tegra_cpu_lock);
	if (event == PM_SUSPEND_PREPARE) {
	is_suspended = true;
	pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n",
	freq_table[tegra_data->suspend_index].frequency);
	tegra_update_cpu_speed(policy,
	freq_table[tegra_data->suspend_index].frequency);
	cpufreq_cpu_put(policy);
	} else if (event == PM_POST_SUSPEND) {
	is_suspended = false;
	tegra_update_cpu_speed(policy, policy->max);
	pr_info("Tegra cpufreq resume: restore frequency to %u kHz\n",
	policy->max);
	cpufreq_cpu_put(policy);
	}
	mutex_unlock(&tegra_cpu_lock);

	return NOTIFY_OK;
	}

	static struct notifier_block tegra_cpu_pm_notifier = {
	.notifier_call = tegra_pm_notify,
	};

	static int tegra_cpu_init(struct cpufreq_policy *policy)
	{
	if (soc_config->cpufreq_clk_init)
	soc_config->cpufreq_clk_init();

	cpufreq_frequency_table_cpuinfo(policy, tegra_data->freq_table);
	cpufreq_frequency_table_get_attr(tegra_data->freq_table, policy->cpu);
	policy->cur = tegra_getspeed(policy->cpu);
	target_cpu_speed[policy->cpu] = policy->cur;

	/* FIXME: what's the actual transition time? */
	policy->cpuinfo.transition_latency = 300 * 1000;

	cpumask_copy(policy->cpus, cpu_possible_mask);

	if (policy->cpu == 0)
	register_pm_notifier(&tegra_cpu_pm_notifier);

	return 0;
	}

	static int tegra_cpu_exit(struct cpufreq_policy *policy)
	{
	cpufreq_frequency_table_cpuinfo(policy, tegra_data->freq_table);
	if (soc_config->cpufreq_clk_exit)
	soc_config->cpufreq_clk_exit();
	return 0;
	}

	static struct freq_attr *tegra_cpufreq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
	};

	static struct cpufreq_driver tegra_cpufreq_driver = {
	.verify = tegra_verify_speed,
	.target = tegra_target,
	.get = tegra_getspeed,
	.init = tegra_cpu_init,
	.exit = tegra_cpu_exit,
	.name = "tegra",
	.attr = tegra_cpufreq_attr,
	};

	static struct {
	char *compat;
	int (init)(struct tegra_cpufreq_data ,
	const struct tegra_cpufreq_config **);
	} tegra_init_funcs[] = {
	{ "nvidia,tegra20", tegra20_cpufreq_init },
	{ "nvidia,tegra124", tegra124_cpufreq_init },
	};

	static int tegra_cpufreq_probe(struct platform_device *pdev)
	{
	int i;
	int ret = -EINVAL;

	tegra_data = devm_kzalloc(&pdev->dev,
	sizeof(*tegra_data), GFP_KERNEL);
	if (!tegra_data) {
	ret = -ENOMEM;
	goto out;
	}

	tegra_data->dev = &pdev->dev;

	for (i = 0; i < ARRAY_SIZE(tegra_init_funcs); i++) {
	if (of_machine_is_compatible(tegra_init_funcs[i].compat)) {
	ret = tegra_init_funcs[i].init(tegra_data, &soc_config);
	if (!ret)
	break;
	else
	goto out;
	}
	}
	if (i == ARRAY_SIZE(tegra_init_funcs))
	goto out;

	ret = cpufreq_register_driver(&tegra_cpufreq_driver);
	if (ret) {
	dev_err(tegra_data->dev,
	"%s: failed to register cpufreq driver\n", __func__);
	goto out;
	}

	return 0;
	out:
	return ret;
	}

	static int tegra_cpufreq_remove(struct platform_device *pdev)
	{
	cpufreq_unregister_driver(&tegra_cpufreq_driver);
	return 0;
	}

	static struct platform_driver tegra_cpufreq_platdrv = {
	.driver = {
	.name = "tegra-cpufreq",
	.owner = THIS_MODULE,
	},
	.probe = tegra_cpufreq_probe,
	.remove = tegra_cpufreq_remove,
	};
	module_platform_driver(tegra_cpufreq_platdrv);

	int __init tegra_cpufreq_init(void)
	{
	struct platform_device_info devinfo = { .name = "tegra-cpufreq", };

	platform_device_register_full(&devinfo);

	return 0;
	}
	EXPORT_SYMBOL(tegra_cpufreq_init);


	MODULE_AUTHOR("Colin Cross <ccross@android.com>");
	MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
	MODULE_LICENSE("GPL");