linux-imx

/*

 *  drivers/cpufreq/cpufreq_conservative.c

 *

 *  Copyright (C)  2001 Russell King

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

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

 *            (C)  2009 Alexander Clouter <alex@digriz.org.uk>

 *

 * 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.

 */

​

#include <linux/slab.h>

#include "cpufreq_governor.h"

​

struct cs_policy_dbs_info {

    struct policy_dbs_info policy_dbs;

    unsigned int down_skip;

    unsigned int requested_freq;

};

​

static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs)

{

    return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs);

}

​

struct cs_dbs_tuners {

    unsigned int down_threshold;

    unsigned int freq_step;

};

​

/* Conservative governor macros */

#define DEF_FREQUENCY_UP_THRESHOLD      (80)

#define DEF_FREQUENCY_DOWN_THRESHOLD        (20)

#define DEF_FREQUENCY_STEP          (5)

#define DEF_SAMPLING_DOWN_FACTOR        (1)

#define MAX_SAMPLING_DOWN_FACTOR        (10)

​

static inline unsigned int get_freq_step(struct cs_dbs_tuners *cs_tuners,

                     struct cpufreq_policy *policy)

{

    unsigned int freq_step = (cs_tuners->freq_step * policy->max) / 100;

​

    /* max freq cannot be less than 100. But who knows... */

    if (unlikely(freq_step == 0))

        freq_step = DEF_FREQUENCY_STEP;

​

    return freq_step;

}

​

/*

 * Every sampling_rate, we check, if current idle time is less than 20%

 * (default), then we try to increase frequency. Every sampling_rate *

 * sampling_down_factor, we check, if current idle time is more than 80%

 * (default), then we try to decrease frequency

 *

 * Frequency updates happen at minimum steps of 5% (default) of maximum

 * frequency

 */

static unsigned int cs_dbs_update(struct cpufreq_policy *policy)

{

    struct policy_dbs_info *policy_dbs = policy->governor_data;