drivers/cpufreq/cpufreq-cpu0.c - maze/linux - Git at Google

 /*
  * Copyright (C) 2012 Freescale Semiconductor, Inc.
  *
  * The OPP code in function cpu0_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/cpufreq.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/opp.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.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 int cpu0_verify_speed(struct cpufreq_policy *policy)
 {
 	return cpufreq_frequency_table_verify(policy, freq_table);
 }

 static unsigned int cpu0_get_speed(unsigned int cpu)
 {
 	return clk_get_rate(cpu_clk) / 1000;
 }

 static int cpu0_set_target(struct cpufreq_policy *policy,
 			   unsigned int target_freq, unsigned int relation)
 {
 	struct cpufreq_freqs freqs;
 	struct opp *opp;
 	unsigned long freq_Hz, volt = 0, volt_old = 0, tol = 0;
 	unsigned int index, cpu;
 	int ret;

 	ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
 					     relation, &index);
 	if (ret) {
 		pr_err("failed to match target freqency %d: %d\n",
 		       target_freq, ret);
 		return ret;
 	}

 	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
 	if (freq_Hz < 0)
 		freq_Hz = freq_table[index].frequency * 1000;
 	freqs.new = freq_Hz / 1000;
 	freqs.old = clk_get_rate(cpu_clk) / 1000;

 	if (freqs.old == freqs.new)
 		return 0;

 	for_each_online_cpu(cpu) {
 		freqs.cpu = cpu;
 		cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 	}

 	if (cpu_reg) {
 		opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);
 		if (IS_ERR(opp)) {
 			pr_err("failed to find OPP for %ld\n", freq_Hz);
 			return PTR_ERR(opp);
 		}
 		volt = opp_get_voltage(opp);
 		tol = volt * voltage_tolerance / 100;
 		volt_old = regulator_get_voltage(cpu_reg);
 	}

 	pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
 		 freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
 		 freqs.new / 1000, volt ? volt / 1000 : -1);

 	/* scaling up?  scale voltage before frequency */
 	if (cpu_reg && freqs.new > freqs.old) {
 		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
 		if (ret) {
 			pr_err("failed to scale voltage up: %d\n", ret);
 			freqs.new = freqs.old;
 			return ret;
 		}
 	}

 	ret = clk_set_rate(cpu_clk, freqs.new * 1000);
 	if (ret) {
 		pr_err("failed to set clock rate: %d\n", ret);
 		if (cpu_reg)
 			regulator_set_voltage_tol(cpu_reg, volt_old, tol);
 		return ret;
 	}

 	/* scaling down?  scale voltage after frequency */
 	if (cpu_reg && freqs.new < freqs.old) {
 		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
 		if (ret) {
 			pr_err("failed to scale voltage down: %d\n", ret);
 			clk_set_rate(cpu_clk, freqs.old * 1000);
 			freqs.new = freqs.old;
 			return ret;
 		}
 	}

 	for_each_online_cpu(cpu) {
 		freqs.cpu = cpu;
 		cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 	}

 	return 0;
 }

 static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
 {
 	int ret;

 	if (policy->cpu != 0)
 		return -EINVAL;

 	ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 	if (ret) {
 		pr_err("invalid frequency table: %d\n", ret);
 		return ret;
 	}

 	policy->cpuinfo.transition_latency = transition_latency;
 	policy->cur = clk_get_rate(cpu_clk) / 1000;

 	/*
 	 * The driver only supports the SMP configuartion where all processors
 	 * share the clock and voltage and clock.  Use cpufreq affected_cpus
 	 * interface to have all CPUs scaled together.
 	 */
 	policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 	cpumask_setall(policy->cpus);

 	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);

 	return 0;
 }

 static int cpu0_cpufreq_exit(struct cpufreq_policy *policy)
 {
 	cpufreq_frequency_table_put_attr(policy->cpu);

 	return 0;
 }

 static struct freq_attr *cpu0_cpufreq_attr[] = {
 	&cpufreq_freq_attr_scaling_available_freqs,
 	NULL,
 };

 static struct cpufreq_driver cpu0_cpufreq_driver = {
 	.flags = CPUFREQ_STICKY,
 	.verify = cpu0_verify_speed,
 	.target = cpu0_set_target,
 	.get = cpu0_get_speed,
 	.init = cpu0_cpufreq_init,
 	.exit = cpu0_cpufreq_exit,
 	.name = "generic_cpu0",
 	.attr = cpu0_cpufreq_attr,
 };

 static int __devinit cpu0_cpufreq_driver_init(void)
 {
 	struct device_node *np;
 	int ret;

 	np = of_find_node_by_path("/cpus/cpu@0");
 	if (!np) {
 		pr_err("failed to find cpu0 node\n");
 		return -ENOENT;
 	}

 	cpu_dev = get_cpu_device(0);
 	if (!cpu_dev) {
 		pr_err("failed to get cpu0 device\n");
 		ret = -ENODEV;
 		goto out_put_node;
 	}

 	cpu_dev->of_node = np;

 	cpu_clk = clk_get(cpu_dev, NULL);
 	if (IS_ERR(cpu_clk)) {
 		ret = PTR_ERR(cpu_clk);
 		pr_err("failed to get cpu0 clock: %d\n", ret);
 		goto out_put_node;
 	}

 	cpu_reg = regulator_get(cpu_dev, "cpu0");
 	if (IS_ERR(cpu_reg)) {
 		pr_warn("failed to get cpu0 regulator\n");
 		cpu_reg = NULL;
 	}

 	ret = of_init_opp_table(cpu_dev);
 	if (ret) {
 		pr_err("failed to init OPP table: %d\n", ret);
 		goto out_put_node;
 	}

 	ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
 	if (ret) {
 		pr_err("failed to init cpufreq table: %d\n", ret);
 		goto out_put_node;
 	}

 	of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);

 	if (of_property_read_u32(np, "clock-latency", &transition_latency))
 		transition_latency = CPUFREQ_ETERNAL;

 	if (cpu_reg) {
 		struct 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++)
 			;
 		opp = opp_find_freq_exact(cpu_dev,
 				freq_table[0].frequency * 1000, true);
 		min_uV = opp_get_voltage(opp);
 		opp = opp_find_freq_exact(cpu_dev,
 				freq_table[i-1].frequency * 1000, true);
 		max_uV = opp_get_voltage(opp);
 		ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
 		if (ret > 0)
 			transition_latency += ret * 1000;
 	}

 	ret = cpufreq_register_driver(&cpu0_cpufreq_driver);
 	if (ret) {
 		pr_err("failed register driver: %d\n", ret);
 		goto out_free_table;
 	}

 	of_node_put(np);
 	return 0;

 out_free_table:
 	opp_free_cpufreq_table(cpu_dev, &freq_table);
 out_put_node:
 	of_node_put(np);
 	return ret;
 }
 late_initcall(cpu0_cpufreq_driver_init);

 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
 MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2012 Freescale Semiconductor, Inc.
	*
	* The OPP code in function cpu0_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/cpufreq.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/opp.h>
	#include <linux/regulator/consumer.h>
	#include <linux/slab.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 int cpu0_verify_speed(struct cpufreq_policy *policy)
	{
	return cpufreq_frequency_table_verify(policy, freq_table);
	}

	static unsigned int cpu0_get_speed(unsigned int cpu)
	{
	return clk_get_rate(cpu_clk) / 1000;
	}

	static int cpu0_set_target(struct cpufreq_policy *policy,
	unsigned int target_freq, unsigned int relation)
	{
	struct cpufreq_freqs freqs;
	struct opp *opp;
	unsigned long freq_Hz, volt = 0, volt_old = 0, tol = 0;
	unsigned int index, cpu;
	int ret;

	ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
	relation, &index);
	if (ret) {
	pr_err("failed to match target freqency %d: %d\n",
	target_freq, ret);
	return ret;
	}

	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
	if (freq_Hz < 0)
	freq_Hz = freq_table[index].frequency * 1000;
	freqs.new = freq_Hz / 1000;
	freqs.old = clk_get_rate(cpu_clk) / 1000;

	if (freqs.old == freqs.new)
	return 0;

	for_each_online_cpu(cpu) {
	freqs.cpu = cpu;
	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	}

	if (cpu_reg) {
	opp = opp_find_freq_ceil(cpu_dev, &freq_Hz);
	if (IS_ERR(opp)) {
	pr_err("failed to find OPP for %ld\n", freq_Hz);
	return PTR_ERR(opp);
	}
	volt = opp_get_voltage(opp);
	tol = volt * voltage_tolerance / 100;
	volt_old = regulator_get_voltage(cpu_reg);
	}

	pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
	freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
	freqs.new / 1000, volt ? volt / 1000 : -1);

	/* scaling up? scale voltage before frequency */
	if (cpu_reg && freqs.new > freqs.old) {
	ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
	if (ret) {
	pr_err("failed to scale voltage up: %d\n", ret);
	freqs.new = freqs.old;
	return ret;
	}
	}

	ret = clk_set_rate(cpu_clk, freqs.new * 1000);
	if (ret) {
	pr_err("failed to set clock rate: %d\n", ret);
	if (cpu_reg)
	regulator_set_voltage_tol(cpu_reg, volt_old, tol);
	return ret;
	}

	/* scaling down? scale voltage after frequency */
	if (cpu_reg && freqs.new < freqs.old) {
	ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
	if (ret) {
	pr_err("failed to scale voltage down: %d\n", ret);
	clk_set_rate(cpu_clk, freqs.old * 1000);
	freqs.new = freqs.old;
	return ret;
	}
	}

	for_each_online_cpu(cpu) {
	freqs.cpu = cpu;
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	}

	return 0;
	}

	static int cpu0_cpufreq_init(struct cpufreq_policy *policy)
	{
	int ret;

	if (policy->cpu != 0)
	return -EINVAL;

	ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
	if (ret) {
	pr_err("invalid frequency table: %d\n", ret);
	return ret;
	}

	policy->cpuinfo.transition_latency = transition_latency;
	policy->cur = clk_get_rate(cpu_clk) / 1000;

	/*
	* The driver only supports the SMP configuartion where all processors
	* share the clock and voltage and clock. Use cpufreq affected_cpus
	* interface to have all CPUs scaled together.
	*/
	policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
	cpumask_setall(policy->cpus);

	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);

	return 0;
	}

	static int cpu0_cpufreq_exit(struct cpufreq_policy *policy)
	{
	cpufreq_frequency_table_put_attr(policy->cpu);

	return 0;
	}

	static struct freq_attr *cpu0_cpufreq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
	};

	static struct cpufreq_driver cpu0_cpufreq_driver = {
	.flags = CPUFREQ_STICKY,
	.verify = cpu0_verify_speed,
	.target = cpu0_set_target,
	.get = cpu0_get_speed,
	.init = cpu0_cpufreq_init,
	.exit = cpu0_cpufreq_exit,
	.name = "generic_cpu0",
	.attr = cpu0_cpufreq_attr,
	};

	static int __devinit cpu0_cpufreq_driver_init(void)
	{
	struct device_node *np;
	int ret;

	np = of_find_node_by_path("/cpus/cpu@0");
	if (!np) {
	pr_err("failed to find cpu0 node\n");
	return -ENOENT;
	}

	cpu_dev = get_cpu_device(0);
	if (!cpu_dev) {
	pr_err("failed to get cpu0 device\n");
	ret = -ENODEV;
	goto out_put_node;
	}

	cpu_dev->of_node = np;

	cpu_clk = clk_get(cpu_dev, NULL);
	if (IS_ERR(cpu_clk)) {
	ret = PTR_ERR(cpu_clk);
	pr_err("failed to get cpu0 clock: %d\n", ret);
	goto out_put_node;
	}

	cpu_reg = regulator_get(cpu_dev, "cpu0");
	if (IS_ERR(cpu_reg)) {
	pr_warn("failed to get cpu0 regulator\n");
	cpu_reg = NULL;
	}

	ret = of_init_opp_table(cpu_dev);
	if (ret) {
	pr_err("failed to init OPP table: %d\n", ret);
	goto out_put_node;
	}

	ret = opp_init_cpufreq_table(cpu_dev, &freq_table);
	if (ret) {
	pr_err("failed to init cpufreq table: %d\n", ret);
	goto out_put_node;
	}

	of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);

	if (of_property_read_u32(np, "clock-latency", &transition_latency))
	transition_latency = CPUFREQ_ETERNAL;

	if (cpu_reg) {
	struct 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++)
	;
	opp = opp_find_freq_exact(cpu_dev,
	freq_table[0].frequency * 1000, true);
	min_uV = opp_get_voltage(opp);
	opp = opp_find_freq_exact(cpu_dev,
	freq_table[i-1].frequency * 1000, true);
	max_uV = opp_get_voltage(opp);
	ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
	if (ret > 0)
	transition_latency += ret * 1000;
	}

	ret = cpufreq_register_driver(&cpu0_cpufreq_driver);
	if (ret) {
	pr_err("failed register driver: %d\n", ret);
	goto out_free_table;
	}

	of_node_put(np);
	return 0;

	out_free_table:
	opp_free_cpufreq_table(cpu_dev, &freq_table);
	out_put_node:
	of_node_put(np);
	return ret;
	}
	late_initcall(cpu0_cpufreq_driver_init);

	MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
	MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
	MODULE_LICENSE("GPL");