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341 lines
8.7 KiB
341 lines
8.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* drivers/cpufreq/cpufreq_conservative.c |
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* |
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* Copyright (C) 2001 Russell King |
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* (C) 2003 Venkatesh Pallipadi <[email protected]>. |
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* Jun Nakajima <[email protected]> |
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* (C) 2009 Alexander Clouter <[email protected]> |
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*/ |
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#include <linux/slab.h> |
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#include "cpufreq_governor.h" |
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struct cs_policy_dbs_info { |
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struct policy_dbs_info policy_dbs; |
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unsigned int down_skip; |
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unsigned int requested_freq; |
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}; |
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static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs) |
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{ |
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return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs); |
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} |
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struct cs_dbs_tuners { |
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unsigned int down_threshold; |
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unsigned int freq_step; |
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}; |
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/* Conservative governor macros */ |
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#define DEF_FREQUENCY_UP_THRESHOLD (80) |
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#define DEF_FREQUENCY_DOWN_THRESHOLD (20) |
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#define DEF_FREQUENCY_STEP (5) |
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#define DEF_SAMPLING_DOWN_FACTOR (1) |
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#define MAX_SAMPLING_DOWN_FACTOR (10) |
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static inline unsigned int get_freq_step(struct cs_dbs_tuners *cs_tuners, |
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struct cpufreq_policy *policy) |
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{ |
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unsigned int freq_step = (cs_tuners->freq_step * policy->max) / 100; |
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/* max freq cannot be less than 100. But who knows... */ |
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if (unlikely(freq_step == 0)) |
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freq_step = DEF_FREQUENCY_STEP; |
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return freq_step; |
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} |
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/* |
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* Every sampling_rate, we check, if current idle time is less than 20% |
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* (default), then we try to increase frequency. Every sampling_rate * |
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* sampling_down_factor, we check, if current idle time is more than 80% |
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* (default), then we try to decrease frequency |
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* |
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* Frequency updates happen at minimum steps of 5% (default) of maximum |
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* frequency |
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*/ |
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static unsigned int cs_dbs_update(struct cpufreq_policy *policy) |
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{ |
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struct policy_dbs_info *policy_dbs = policy->governor_data; |
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struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs); |
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unsigned int requested_freq = dbs_info->requested_freq; |
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struct dbs_data *dbs_data = policy_dbs->dbs_data; |
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struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
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unsigned int load = dbs_update(policy); |
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unsigned int freq_step; |
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/* |
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* break out if we 'cannot' reduce the speed as the user might |
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* want freq_step to be zero |
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*/ |
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if (cs_tuners->freq_step == 0) |
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goto out; |
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/* |
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* If requested_freq is out of range, it is likely that the limits |
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* changed in the meantime, so fall back to current frequency in that |
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* case. |
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*/ |
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if (requested_freq > policy->max || requested_freq < policy->min) { |
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requested_freq = policy->cur; |
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dbs_info->requested_freq = requested_freq; |
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} |
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freq_step = get_freq_step(cs_tuners, policy); |
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/* |
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* Decrease requested_freq one freq_step for each idle period that |
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* we didn't update the frequency. |
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*/ |
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if (policy_dbs->idle_periods < UINT_MAX) { |
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unsigned int freq_steps = policy_dbs->idle_periods * freq_step; |
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if (requested_freq > policy->min + freq_steps) |
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requested_freq -= freq_steps; |
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else |
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requested_freq = policy->min; |
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policy_dbs->idle_periods = UINT_MAX; |
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} |
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/* Check for frequency increase */ |
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if (load > dbs_data->up_threshold) { |
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dbs_info->down_skip = 0; |
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/* if we are already at full speed then break out early */ |
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if (requested_freq == policy->max) |
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goto out; |
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requested_freq += freq_step; |
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if (requested_freq > policy->max) |
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requested_freq = policy->max; |
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__cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_H); |
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dbs_info->requested_freq = requested_freq; |
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goto out; |
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} |
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/* if sampling_down_factor is active break out early */ |
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if (++dbs_info->down_skip < dbs_data->sampling_down_factor) |
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goto out; |
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dbs_info->down_skip = 0; |
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/* Check for frequency decrease */ |
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if (load < cs_tuners->down_threshold) { |
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/* |
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* if we cannot reduce the frequency anymore, break out early |
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*/ |
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if (requested_freq == policy->min) |
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goto out; |
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if (requested_freq > freq_step) |
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requested_freq -= freq_step; |
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else |
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requested_freq = policy->min; |
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__cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L); |
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dbs_info->requested_freq = requested_freq; |
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} |
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out: |
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return dbs_data->sampling_rate; |
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} |
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/************************** sysfs interface ************************/ |
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static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set, |
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const char *buf, size_t count) |
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{ |
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struct dbs_data *dbs_data = to_dbs_data(attr_set); |
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unsigned int input; |
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int ret; |
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ret = sscanf(buf, "%u", &input); |
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if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1) |
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return -EINVAL; |
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dbs_data->sampling_down_factor = input; |
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return count; |
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} |
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static ssize_t store_up_threshold(struct gov_attr_set *attr_set, |
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const char *buf, size_t count) |
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{ |
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struct dbs_data *dbs_data = to_dbs_data(attr_set); |
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struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
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unsigned int input; |
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int ret; |
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ret = sscanf(buf, "%u", &input); |
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if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold) |
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return -EINVAL; |
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dbs_data->up_threshold = input; |
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return count; |
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} |
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static ssize_t store_down_threshold(struct gov_attr_set *attr_set, |
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const char *buf, size_t count) |
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{ |
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struct dbs_data *dbs_data = to_dbs_data(attr_set); |
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struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
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unsigned int input; |
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int ret; |
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ret = sscanf(buf, "%u", &input); |
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/* cannot be lower than 1 otherwise freq will not fall */ |
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if (ret != 1 || input < 1 || input > 100 || |
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input >= dbs_data->up_threshold) |
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return -EINVAL; |
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cs_tuners->down_threshold = input; |
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return count; |
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} |
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static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set, |
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const char *buf, size_t count) |
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{ |
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struct dbs_data *dbs_data = to_dbs_data(attr_set); |
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unsigned int input; |
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int ret; |
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ret = sscanf(buf, "%u", &input); |
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if (ret != 1) |
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return -EINVAL; |
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if (input > 1) |
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input = 1; |
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if (input == dbs_data->ignore_nice_load) /* nothing to do */ |
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return count; |
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dbs_data->ignore_nice_load = input; |
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/* we need to re-evaluate prev_cpu_idle */ |
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gov_update_cpu_data(dbs_data); |
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return count; |
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} |
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static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf, |
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size_t count) |
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{ |
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struct dbs_data *dbs_data = to_dbs_data(attr_set); |
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struct cs_dbs_tuners *cs_tuners = dbs_data->tuners; |
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unsigned int input; |
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int ret; |
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ret = sscanf(buf, "%u", &input); |
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if (ret != 1) |
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return -EINVAL; |
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if (input > 100) |
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input = 100; |
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/* |
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* no need to test here if freq_step is zero as the user might actually |
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* want this, they would be crazy though :) |
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*/ |
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cs_tuners->freq_step = input; |
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return count; |
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} |
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gov_show_one_common(sampling_rate); |
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gov_show_one_common(sampling_down_factor); |
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gov_show_one_common(up_threshold); |
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gov_show_one_common(ignore_nice_load); |
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gov_show_one(cs, down_threshold); |
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gov_show_one(cs, freq_step); |
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gov_attr_rw(sampling_rate); |
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gov_attr_rw(sampling_down_factor); |
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gov_attr_rw(up_threshold); |
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gov_attr_rw(ignore_nice_load); |
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gov_attr_rw(down_threshold); |
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gov_attr_rw(freq_step); |
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static struct attribute *cs_attributes[] = { |
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&sampling_rate.attr, |
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&sampling_down_factor.attr, |
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&up_threshold.attr, |
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&down_threshold.attr, |
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&ignore_nice_load.attr, |
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&freq_step.attr, |
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NULL |
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}; |
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/************************** sysfs end ************************/ |
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static struct policy_dbs_info *cs_alloc(void) |
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{ |
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struct cs_policy_dbs_info *dbs_info; |
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dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL); |
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return dbs_info ? &dbs_info->policy_dbs : NULL; |
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} |
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static void cs_free(struct policy_dbs_info *policy_dbs) |
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{ |
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kfree(to_dbs_info(policy_dbs)); |
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} |
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static int cs_init(struct dbs_data *dbs_data) |
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{ |
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struct cs_dbs_tuners *tuners; |
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tuners = kzalloc(sizeof(*tuners), GFP_KERNEL); |
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if (!tuners) |
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return -ENOMEM; |
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tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD; |
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tuners->freq_step = DEF_FREQUENCY_STEP; |
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dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
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dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR; |
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dbs_data->ignore_nice_load = 0; |
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dbs_data->tuners = tuners; |
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return 0; |
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} |
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static void cs_exit(struct dbs_data *dbs_data) |
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{ |
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kfree(dbs_data->tuners); |
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} |
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static void cs_start(struct cpufreq_policy *policy) |
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{ |
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struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
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dbs_info->down_skip = 0; |
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dbs_info->requested_freq = policy->cur; |
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} |
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static struct dbs_governor cs_governor = { |
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.gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"), |
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.kobj_type = { .default_attrs = cs_attributes }, |
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.gov_dbs_update = cs_dbs_update, |
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.alloc = cs_alloc, |
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.free = cs_free, |
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.init = cs_init, |
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.exit = cs_exit, |
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.start = cs_start, |
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}; |
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#define CPU_FREQ_GOV_CONSERVATIVE (cs_governor.gov) |
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MODULE_AUTHOR("Alexander Clouter <[email protected]>"); |
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MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for " |
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"Low Latency Frequency Transition capable processors " |
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"optimised for use in a battery environment"); |
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MODULE_LICENSE("GPL"); |
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#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE |
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struct cpufreq_governor *cpufreq_default_governor(void) |
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{ |
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return &CPU_FREQ_GOV_CONSERVATIVE; |
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} |
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#endif |
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cpufreq_governor_init(CPU_FREQ_GOV_CONSERVATIVE); |
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cpufreq_governor_exit(CPU_FREQ_GOV_CONSERVATIVE);
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