Release 4.11 drivers/cpufreq/omap-cpufreq.c

/*
 *  CPU frequency scaling for OMAP using OPP information
 *
 *  Copyright (C) 2005 Nokia Corporation
 *  Written by Tony Lindgren <tony@atomide.com>
 *
 *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
 *
 * Copyright (C) 2007-2011 Texas Instruments, Inc.
 * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
 *
 * 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/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/pm_opp.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

#include <asm/smp_plat.h>
#include <asm/cpu.h>

/* OPP tolerance in percentage */

#define	OPP_TOLERANCE	4


static struct cpufreq_frequency_table *freq_table;

static atomic_t freq_table_users = ATOMIC_INIT(0);

static struct device *mpu_dev;

static struct regulator *mpu_reg;



static int omap_target(struct cpufreq_policy *policy, unsigned int index)
{
	int r, ret;
	struct dev_pm_opp *opp;
	unsigned long freq, volt = 0, volt_old = 0, tol = 0;
	unsigned int old_freq, new_freq;

	old_freq = policy->cur;
	new_freq = freq_table[index].frequency;

	freq = new_freq * 1000;
	ret = clk_round_rate(policy->clk, freq);
	if (ret < 0) {
		dev_warn(mpu_dev,
			 "CPUfreq: Cannot find matching frequency for %lu\n",
			 freq);
		return ret;
	}
	freq = ret;

	if (mpu_reg) {
		opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
		if (IS_ERR(opp)) {
			dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
				__func__, new_freq);
			return -EINVAL;
		}
		volt = dev_pm_opp_get_voltage(opp);
		dev_pm_opp_put(opp);
		tol = volt * OPP_TOLERANCE / 100;
		volt_old = regulator_get_voltage(mpu_reg);
	}

	dev_dbg(mpu_dev, "cpufreq-omap: %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 (mpu_reg && (new_freq > old_freq)) {
		r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
		if (r < 0) {
			dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
				 __func__);
			return r;
		}
	}

	ret = clk_set_rate(policy->clk, new_freq * 1000);

	/* scaling down?  scale voltage after frequency */
	if (mpu_reg && (new_freq < old_freq)) {
		r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
		if (r < 0) {
			dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
				 __func__);
			clk_set_rate(policy->clk, old_freq * 1000);
			return r;
		}
	}

	return ret;
}

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Viresh Kumar
45
13.80%
5
33.33%
Tony Lindgren
27
8.28%
1
6.67%
Afzal Mohammed
20
6.13%
1
6.67%
Nishanth Menon
10
3.07%
4
26.67%
Arnd Bergmann
2
0.61%
1
6.67%
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326
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15
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static inline void freq_table_free(void)
{
	if (atomic_dec_and_test(&freq_table_users))
		dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
}

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static int omap_cpu_init(struct cpufreq_policy *policy)
{
	int result;

	policy->clk = clk_get(NULL, "cpufreq_ck");
	if (IS_ERR(policy->clk))
		return PTR_ERR(policy->clk);

	if (!freq_table) {
		result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
		if (result) {
			dev_err(mpu_dev,
				"%s: cpu%d: failed creating freq table[%d]\n",
				__func__, policy->cpu, result);
			goto fail;
		}
	}

	atomic_inc_return(&freq_table_users);

	/* FIXME: what's the actual transition time? */
	result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
	if (!result)
		return 0;

	freq_table_free();
fail:
	clk_put(policy->clk);
	return result;
}

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Viresh Kumar
22
17.46%
2
15.38%
Kevin Hilman
19
15.08%
1
7.69%
Rajendra Nayak
8
6.35%
1
7.69%
Russell King
5
3.97%
1
7.69%
Hiroshi Doyu
4
3.17%
1
7.69%
Santosh Shilimkar
3
2.38%
1
7.69%
Paul Walmsley
1
0.79%
1
7.69%
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126
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13
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static int omap_cpu_exit(struct cpufreq_policy *policy)
{
	freq_table_free();
	clk_put(policy->clk);
	return 0;
}

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3
12.50%
1
25.00%
Viresh Kumar
3
12.50%
1
25.00%
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24
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4
100.00%


static struct cpufreq_driver omap_driver = {
	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	.verify		= cpufreq_generic_frequency_table_verify,
	.target_index	= omap_target,
	.get		= cpufreq_generic_get,
	.init		= omap_cpu_init,
	.exit		= omap_cpu_exit,
	.name		= "omap",
	.attr		= cpufreq_generic_attr,
};



static int omap_cpufreq_probe(struct platform_device *pdev)
{
	mpu_dev = get_cpu_device(0);
	if (!mpu_dev) {
		pr_warn("%s: unable to get the MPU device\n", __func__);
		return -EINVAL;
	}

	mpu_reg = regulator_get(mpu_dev, "vcc");
	if (IS_ERR(mpu_reg)) {
		pr_warn("%s: unable to get MPU regulator\n", __func__);
		mpu_reg = NULL;
	} else {
		/* 
                 * Ensure physical regulator is present.
                 * (e.g. could be dummy regulator.)
                 */
		if (regulator_get_voltage(mpu_reg) < 0) {
			pr_warn("%s: physical regulator not present for MPU\n",
				__func__);
			regulator_put(mpu_reg);
			mpu_reg = NULL;
		}
	}

	return cpufreq_register_driver(&omap_driver);
}

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2
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static int omap_cpufreq_remove(struct platform_device *pdev)
{
	return cpufreq_unregister_driver(&omap_driver);
}

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static struct platform_driver omap_cpufreq_platdrv = {
	.driver = {
		.name	= "omap-cpufreq",
        },
	.probe		= omap_cpufreq_probe,
	.remove		= omap_cpufreq_remove,
};

module_platform_driver(omap_cpufreq_platdrv);

MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
MODULE_LICENSE("GPL");
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Tony Lindgren
144
17.98%
1
2.78%
Viresh Kumar
76
9.49%
8
22.22%
Afzal Mohammed
25
3.12%
1
2.78%
Santosh Shilimkar
22
2.75%
1
2.78%
Hiroshi Doyu
19
2.37%
1
2.78%
Russell King
11
1.37%
3
8.33%
Joe Perches
10
1.25%
2
5.56%
Rajendra Nayak
8
1.00%
1
2.78%
Arnd Bergmann
2
0.25%
1
2.78%
Paul Walmsley
1
0.12%
1
2.78%
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Directory: drivers/cpufreq

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