linux-imx

/*

 *  drivers/cpufreq/cpufreq_ondemand.c

 *

 *  Copyright (C)  2001 Russell King

 *            (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.

 *                      Jun Nakajima <jun.nakajima@intel.com>

 *

 * 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/cpu.h>

#include <linux/percpu-defs.h>

#include <linux/slab.h>

#include <linux/tick.h>

#include <linux/sched/cpufreq.h>

​

#include "cpufreq_ondemand.h"

​

/* On-demand governor macros */

#define DEF_FREQUENCY_UP_THRESHOLD      (80)

#define DEF_SAMPLING_DOWN_FACTOR        (1)

#define MAX_SAMPLING_DOWN_FACTOR        (100000)

#define MICRO_FREQUENCY_UP_THRESHOLD        (95)

#define MICRO_FREQUENCY_MIN_SAMPLE_RATE     (10000)

#define MIN_FREQUENCY_UP_THRESHOLD      (1)

#define MAX_FREQUENCY_UP_THRESHOLD      (100)

​

static struct od_ops od_ops;

​

static unsigned int default_powersave_bias;

​

/*

 * Not all CPUs want IO time to be accounted as busy; this depends on how

 * efficient idling at a higher frequency/voltage is.

 * Pavel Machek says this is not so for various generations of AMD and old

 * Intel systems.

 * Mike Chan (android.com) claims this is also not true for ARM.

 * Because of this, whitelist specific known (series) of CPUs by default, and

 * leave all others up to the user.

 */

static int should_io_be_busy(void)

{

#if defined(CONFIG_X86)

    /*

     * For Intel, Core 2 (model 15) and later have an efficient idle.

     */

    if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&

            boot_cpu_data.x86 == 6 &&

            boot_cpu_data.x86_model >= 15)

        return 1;

#endif

    return 0;

}

​

/*

 * Find right freq to be set now with powersave_bias on.

 * Returns the freq_hi to be used right now and will set freq_hi_delay_us,

 * freq_lo, and freq_lo_delay_us in percpu area for averaging freqs.

 */