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478 lines
13 KiB
478 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* drivers/cpufreq/cpufreq_ondemand.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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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/cpu.h> |
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#include <linux/percpu-defs.h> |
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#include <linux/slab.h> |
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#include <linux/tick.h> |
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#include <linux/sched/cpufreq.h> |
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#include "cpufreq_ondemand.h" |
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/* On-demand governor macros */ |
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#define DEF_FREQUENCY_UP_THRESHOLD (80) |
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#define DEF_SAMPLING_DOWN_FACTOR (1) |
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#define MAX_SAMPLING_DOWN_FACTOR (100000) |
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#define MICRO_FREQUENCY_UP_THRESHOLD (95) |
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#define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000) |
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#define MIN_FREQUENCY_UP_THRESHOLD (1) |
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#define MAX_FREQUENCY_UP_THRESHOLD (100) |
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static struct od_ops od_ops; |
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static unsigned int default_powersave_bias; |
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/* |
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* Not all CPUs want IO time to be accounted as busy; this depends on how |
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* efficient idling at a higher frequency/voltage is. |
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* Pavel Machek says this is not so for various generations of AMD and old |
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* Intel systems. |
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* Mike Chan (android.com) claims this is also not true for ARM. |
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* Because of this, whitelist specific known (series) of CPUs by default, and |
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* leave all others up to the user. |
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*/ |
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static int should_io_be_busy(void) |
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{ |
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#if defined(CONFIG_X86) |
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/* |
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* For Intel, Core 2 (model 15) and later have an efficient idle. |
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*/ |
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if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && |
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boot_cpu_data.x86 == 6 && |
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boot_cpu_data.x86_model >= 15) |
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return 1; |
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#endif |
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return 0; |
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} |
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/* |
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* Find right freq to be set now with powersave_bias on. |
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* Returns the freq_hi to be used right now and will set freq_hi_delay_us, |
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* freq_lo, and freq_lo_delay_us in percpu area for averaging freqs. |
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*/ |
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static unsigned int generic_powersave_bias_target(struct cpufreq_policy *policy, |
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unsigned int freq_next, unsigned int relation) |
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{ |
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unsigned int freq_req, freq_reduc, freq_avg; |
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unsigned int freq_hi, freq_lo; |
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unsigned int index; |
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unsigned int delay_hi_us; |
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struct policy_dbs_info *policy_dbs = policy->governor_data; |
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struct od_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs); |
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struct dbs_data *dbs_data = policy_dbs->dbs_data; |
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struct od_dbs_tuners *od_tuners = dbs_data->tuners; |
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struct cpufreq_frequency_table *freq_table = policy->freq_table; |
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if (!freq_table) { |
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dbs_info->freq_lo = 0; |
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dbs_info->freq_lo_delay_us = 0; |
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return freq_next; |
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} |
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index = cpufreq_frequency_table_target(policy, freq_next, relation); |
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freq_req = freq_table[index].frequency; |
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freq_reduc = freq_req * od_tuners->powersave_bias / 1000; |
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freq_avg = freq_req - freq_reduc; |
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/* Find freq bounds for freq_avg in freq_table */ |
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index = cpufreq_table_find_index_h(policy, freq_avg); |
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freq_lo = freq_table[index].frequency; |
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index = cpufreq_table_find_index_l(policy, freq_avg); |
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freq_hi = freq_table[index].frequency; |
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/* Find out how long we have to be in hi and lo freqs */ |
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if (freq_hi == freq_lo) { |
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dbs_info->freq_lo = 0; |
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dbs_info->freq_lo_delay_us = 0; |
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return freq_lo; |
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} |
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delay_hi_us = (freq_avg - freq_lo) * dbs_data->sampling_rate; |
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delay_hi_us += (freq_hi - freq_lo) / 2; |
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delay_hi_us /= freq_hi - freq_lo; |
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dbs_info->freq_hi_delay_us = delay_hi_us; |
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dbs_info->freq_lo = freq_lo; |
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dbs_info->freq_lo_delay_us = dbs_data->sampling_rate - delay_hi_us; |
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return freq_hi; |
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} |
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static void ondemand_powersave_bias_init(struct cpufreq_policy *policy) |
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{ |
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struct od_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
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dbs_info->freq_lo = 0; |
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} |
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static void dbs_freq_increase(struct cpufreq_policy *policy, unsigned int freq) |
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{ |
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struct policy_dbs_info *policy_dbs = policy->governor_data; |
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struct dbs_data *dbs_data = policy_dbs->dbs_data; |
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struct od_dbs_tuners *od_tuners = dbs_data->tuners; |
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if (od_tuners->powersave_bias) |
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freq = od_ops.powersave_bias_target(policy, freq, |
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CPUFREQ_RELATION_H); |
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else if (policy->cur == policy->max) |
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return; |
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__cpufreq_driver_target(policy, freq, od_tuners->powersave_bias ? |
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CPUFREQ_RELATION_L : CPUFREQ_RELATION_H); |
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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. Else, we adjust the frequency |
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* proportional to load. |
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*/ |
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static void od_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 od_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs); |
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struct dbs_data *dbs_data = policy_dbs->dbs_data; |
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struct od_dbs_tuners *od_tuners = dbs_data->tuners; |
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unsigned int load = dbs_update(policy); |
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dbs_info->freq_lo = 0; |
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/* Check for frequency increase */ |
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if (load > dbs_data->up_threshold) { |
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/* If switching to max speed, apply sampling_down_factor */ |
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if (policy->cur < policy->max) |
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policy_dbs->rate_mult = dbs_data->sampling_down_factor; |
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dbs_freq_increase(policy, policy->max); |
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} else { |
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/* Calculate the next frequency proportional to load */ |
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unsigned int freq_next, min_f, max_f; |
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min_f = policy->cpuinfo.min_freq; |
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max_f = policy->cpuinfo.max_freq; |
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freq_next = min_f + load * (max_f - min_f) / 100; |
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/* No longer fully busy, reset rate_mult */ |
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policy_dbs->rate_mult = 1; |
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if (od_tuners->powersave_bias) |
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freq_next = od_ops.powersave_bias_target(policy, |
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freq_next, |
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CPUFREQ_RELATION_L); |
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__cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_C); |
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} |
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} |
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static unsigned int od_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 dbs_data *dbs_data = policy_dbs->dbs_data; |
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struct od_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs); |
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int sample_type = dbs_info->sample_type; |
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/* Common NORMAL_SAMPLE setup */ |
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dbs_info->sample_type = OD_NORMAL_SAMPLE; |
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/* |
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* OD_SUB_SAMPLE doesn't make sense if sample_delay_ns is 0, so ignore |
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* it then. |
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*/ |
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if (sample_type == OD_SUB_SAMPLE && policy_dbs->sample_delay_ns > 0) { |
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__cpufreq_driver_target(policy, dbs_info->freq_lo, |
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CPUFREQ_RELATION_H); |
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return dbs_info->freq_lo_delay_us; |
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} |
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od_update(policy); |
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if (dbs_info->freq_lo) { |
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/* Setup SUB_SAMPLE */ |
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dbs_info->sample_type = OD_SUB_SAMPLE; |
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return dbs_info->freq_hi_delay_us; |
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} |
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return dbs_data->sampling_rate * policy_dbs->rate_mult; |
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} |
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/************************** sysfs interface ************************/ |
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static struct dbs_governor od_dbs_gov; |
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static ssize_t store_io_is_busy(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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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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dbs_data->io_is_busy = !!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_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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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_FREQUENCY_UP_THRESHOLD || |
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input < MIN_FREQUENCY_UP_THRESHOLD) { |
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return -EINVAL; |
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} |
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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_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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struct policy_dbs_info *policy_dbs; |
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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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/* Reset down sampling multiplier in case it was active */ |
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list_for_each_entry(policy_dbs, &attr_set->policy_list, list) { |
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/* |
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* Doing this without locking might lead to using different |
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* rate_mult values in od_update() and od_dbs_update(). |
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*/ |
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mutex_lock(&policy_dbs->update_mutex); |
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policy_dbs->rate_mult = 1; |
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mutex_unlock(&policy_dbs->update_mutex); |
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} |
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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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} |
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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_powersave_bias(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 od_dbs_tuners *od_tuners = dbs_data->tuners; |
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struct policy_dbs_info *policy_dbs; |
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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 > 1000) |
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input = 1000; |
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od_tuners->powersave_bias = input; |
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list_for_each_entry(policy_dbs, &attr_set->policy_list, list) |
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ondemand_powersave_bias_init(policy_dbs->policy); |
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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(up_threshold); |
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gov_show_one_common(sampling_down_factor); |
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gov_show_one_common(ignore_nice_load); |
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gov_show_one_common(io_is_busy); |
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gov_show_one(od, powersave_bias); |
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gov_attr_rw(sampling_rate); |
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gov_attr_rw(io_is_busy); |
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gov_attr_rw(up_threshold); |
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gov_attr_rw(sampling_down_factor); |
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gov_attr_rw(ignore_nice_load); |
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gov_attr_rw(powersave_bias); |
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static struct attribute *od_attributes[] = { |
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&sampling_rate.attr, |
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&up_threshold.attr, |
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&sampling_down_factor.attr, |
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&ignore_nice_load.attr, |
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&powersave_bias.attr, |
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&io_is_busy.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 *od_alloc(void) |
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{ |
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struct od_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 od_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 od_init(struct dbs_data *dbs_data) |
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{ |
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struct od_dbs_tuners *tuners; |
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u64 idle_time; |
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int cpu; |
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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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cpu = get_cpu(); |
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idle_time = get_cpu_idle_time_us(cpu, NULL); |
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put_cpu(); |
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if (idle_time != -1ULL) { |
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/* Idle micro accounting is supported. Use finer thresholds */ |
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dbs_data->up_threshold = MICRO_FREQUENCY_UP_THRESHOLD; |
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} else { |
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dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD; |
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} |
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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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tuners->powersave_bias = default_powersave_bias; |
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dbs_data->io_is_busy = should_io_be_busy(); |
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dbs_data->tuners = tuners; |
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return 0; |
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} |
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static void od_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 od_start(struct cpufreq_policy *policy) |
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{ |
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struct od_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data); |
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dbs_info->sample_type = OD_NORMAL_SAMPLE; |
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ondemand_powersave_bias_init(policy); |
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} |
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static struct od_ops od_ops = { |
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.powersave_bias_target = generic_powersave_bias_target, |
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}; |
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static struct dbs_governor od_dbs_gov = { |
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.gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("ondemand"), |
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.kobj_type = { .default_attrs = od_attributes }, |
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.gov_dbs_update = od_dbs_update, |
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.alloc = od_alloc, |
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.free = od_free, |
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.init = od_init, |
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.exit = od_exit, |
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.start = od_start, |
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}; |
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#define CPU_FREQ_GOV_ONDEMAND (od_dbs_gov.gov) |
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static void od_set_powersave_bias(unsigned int powersave_bias) |
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{ |
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unsigned int cpu; |
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cpumask_t done; |
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default_powersave_bias = powersave_bias; |
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cpumask_clear(&done); |
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get_online_cpus(); |
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for_each_online_cpu(cpu) { |
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struct cpufreq_policy *policy; |
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struct policy_dbs_info *policy_dbs; |
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struct dbs_data *dbs_data; |
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struct od_dbs_tuners *od_tuners; |
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if (cpumask_test_cpu(cpu, &done)) |
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continue; |
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policy = cpufreq_cpu_get_raw(cpu); |
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if (!policy || policy->governor != &CPU_FREQ_GOV_ONDEMAND) |
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continue; |
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policy_dbs = policy->governor_data; |
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if (!policy_dbs) |
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continue; |
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cpumask_or(&done, &done, policy->cpus); |
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dbs_data = policy_dbs->dbs_data; |
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od_tuners = dbs_data->tuners; |
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od_tuners->powersave_bias = default_powersave_bias; |
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} |
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put_online_cpus(); |
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} |
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void od_register_powersave_bias_handler(unsigned int (*f) |
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(struct cpufreq_policy *, unsigned int, unsigned int), |
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unsigned int powersave_bias) |
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{ |
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od_ops.powersave_bias_target = f; |
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od_set_powersave_bias(powersave_bias); |
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} |
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EXPORT_SYMBOL_GPL(od_register_powersave_bias_handler); |
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void od_unregister_powersave_bias_handler(void) |
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{ |
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od_ops.powersave_bias_target = generic_powersave_bias_target; |
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od_set_powersave_bias(0); |
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} |
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EXPORT_SYMBOL_GPL(od_unregister_powersave_bias_handler); |
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MODULE_AUTHOR("Venkatesh Pallipadi <[email protected]>"); |
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MODULE_AUTHOR("Alexey Starikovskiy <[email protected]>"); |
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MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for " |
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"Low Latency Frequency Transition capable processors"); |
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MODULE_LICENSE("GPL"); |
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#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND |
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struct cpufreq_governor *cpufreq_default_governor(void) |
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{ |
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return &CPU_FREQ_GOV_ONDEMAND; |
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} |
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#endif |
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cpufreq_governor_init(CPU_FREQ_GOV_ONDEMAND); |
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cpufreq_governor_exit(CPU_FREQ_GOV_ONDEMAND);
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