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devfreq: Add Active Watermark governor
This patch adds a new watermark governor that actively alters the watermark values based on the current frequency and target load. The governor takes target load as a given property (80% by default) and every time when the governor re-estimation is triggered, the governor checks the current load and calculates the next frequency that would push the device as close this target load as possible. At this point also the watermark values are updated so that next time the interrupt should come when the load change is significant enough to cause frequency change to either next or previous frequency. Change-Id: I860a0bc984d55628a0e560652a93306616b080cf Signed-off-by: Arto Merilainen <amerilainen@nvidia.com> Reviewed-on: http://git-master/r/598801 Reviewed-on: http://git-master/r/1160008 (cherry picked from linux-4.9 commit e55ba2a709574ce4f01ca2f8211393c795b75dad) [talho: removed Kconfig and Makefile changes from the patch] Signed-off-by: Timo Alho <talho@nvidia.com> Reviewed-on: https://git-master.nvidia.com/r/1770140 Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com> GVS: Gerrit_Virtual_Submit Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com> Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
This commit is contained in:
Arto Merilainen
committed by
Laxman Dewangan
Laxman Dewangan
parent
526edececa
commit
6135535c12
288
drivers/devfreq/governor_wmark_active.c
Normal file
288
drivers/devfreq/governor_wmark_active.c
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/*
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* Copyright (c) 2014, NVIDIA CORPORATION. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/devfreq.h>
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#include <linux/debugfs.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/notifier.h>
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#include <linux/platform_device.h>
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#include <governor.h>
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struct wmark_gov_info {
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/* probed from the devfreq */
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unsigned long *freqlist;
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int freq_count;
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/* algorithm parameters */
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unsigned int p_load_target;
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unsigned int p_load_max;
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/* common data */
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struct devfreq *df;
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struct platform_device *pdev;
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struct dentry *debugdir;
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};
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static unsigned long freqlist_up(struct wmark_gov_info *wmarkinfo,
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unsigned long curr_freq)
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{
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int i, pos;
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for (i = 0; i < wmarkinfo->freq_count; i++)
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if (wmarkinfo->freqlist[i] > curr_freq)
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break;
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pos = min(wmarkinfo->freq_count - 1, i);
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return wmarkinfo->freqlist[pos];
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}
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static unsigned long freqlist_down(struct wmark_gov_info *wmarkinfo,
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unsigned long curr_freq)
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{
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int i, pos;
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for (i = wmarkinfo->freq_count - 1; i >= 0; i--)
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if (wmarkinfo->freqlist[i] < curr_freq)
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break;
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pos = max(0, i);
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return wmarkinfo->freqlist[pos];
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}
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static unsigned long freqlist_round(struct wmark_gov_info *wmarkinfo,
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unsigned long freq)
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{
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int i, pos;
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for (i = 0; i < wmarkinfo->freq_count; i++)
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if (wmarkinfo->freqlist[i] >= freq)
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break;
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pos = min(wmarkinfo->freq_count - 1, i);
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return wmarkinfo->freqlist[pos];
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}
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static void update_watermarks(struct devfreq *df,
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unsigned long current_frequency)
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{
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struct wmark_gov_info *wmarkinfo = df->data;
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unsigned long long relation = 0, next_freq = 0;
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unsigned long long current_frequency_khz = current_frequency / 1000;
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if (current_frequency == wmarkinfo->freqlist[0]) {
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/* disable the low watermark if we are at lowest clock */
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df->profile->set_low_wmark(df->dev.parent, 0);
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} else {
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/* calculate the low threshold; what is the load value
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* at which we would go into lower frequency given the
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* that we are running at the new frequency? */
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next_freq = freqlist_down(wmarkinfo, current_frequency);
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relation = ((next_freq / current_frequency_khz) *
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wmarkinfo->p_load_target) / 1000;
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df->profile->set_low_wmark(df->dev.parent, relation);
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}
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if (current_frequency ==
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wmarkinfo->freqlist[wmarkinfo->freq_count - 1]) {
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/* disable the high watermark if we are at highest clock */
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df->profile->set_high_wmark(df->dev.parent, 1000);
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} else {
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/* calculate the high threshold; what is the load value
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* at which we would go into highest frequency given the
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* that we are running at the new frequency? */
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next_freq = freqlist_up(wmarkinfo, current_frequency);
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relation = ((next_freq / current_frequency_khz) *
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wmarkinfo->p_load_target) / 1000;
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relation = min((unsigned long long)wmarkinfo->p_load_max,
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relation);
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df->profile->set_high_wmark(df->dev.parent, relation);
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}
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}
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static int devfreq_watermark_target_freq(struct devfreq *df,
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unsigned long *freq)
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{
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struct wmark_gov_info *wmarkinfo = df->data;
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struct devfreq_dev_status dev_stat;
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unsigned long long load, relation, next_freq;
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int err;
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err = df->profile->get_dev_status(df->dev.parent, &dev_stat);
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if (err < 0)
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return err;
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/* keep current frequency if we do not have proper data available */
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if (!dev_stat.total_time) {
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*freq = dev_stat.current_frequency;
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return 0;
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}
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/* calculate first load and relation load/p_load_target */
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load = (dev_stat.busy_time * 1000) / dev_stat.total_time;
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/* if we cross load max... */
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if (load >= wmarkinfo->p_load_max) {
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/* we go directly to the highest frequency. depending
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* on frequency table we might never go higher than
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* the current frequency (i.e. load should be over 100%
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* to make relation push to the next frequency). */
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*freq = wmarkinfo->freqlist[wmarkinfo->freq_count - 1];
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} else {
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/* otherwise, based on relation between current load and
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* load target we calculate the "ideal" frequency
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* where we would be just at the target */
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relation = (load * 1000) / wmarkinfo->p_load_target;
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next_freq = relation * (dev_stat.current_frequency / 1000);
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/* round this frequency */
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*freq = freqlist_round(wmarkinfo, next_freq);
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}
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/* update watermarks to match with the new frequency */
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update_watermarks(df, *freq);
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return 0;
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}
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static void devfreq_watermark_debug_start(struct devfreq *df)
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{
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struct wmark_gov_info *wmarkinfo = df->data;
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struct dentry *f;
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char dirname[128];
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snprintf(dirname, sizeof(dirname), "%s_scaling",
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to_platform_device(df->dev.parent)->name);
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if (!wmarkinfo)
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return;
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wmarkinfo->debugdir = debugfs_create_dir(dirname, NULL);
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if (!wmarkinfo->debugdir) {
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pr_warn("cannot create debugfs directory\n");
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return;
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}
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#define CREATE_DBG_FILE(fname) \
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do {\
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f = debugfs_create_u32(#fname, S_IRUGO | S_IWUSR, \
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wmarkinfo->debugdir, &wmarkinfo->p_##fname); \
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if (NULL == f) { \
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pr_warn("cannot create debug entry " #fname "\n"); \
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return; \
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} \
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} while (0)
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CREATE_DBG_FILE(load_target);
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CREATE_DBG_FILE(load_max);
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#undef CREATE_DBG_FILE
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}
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static void devfreq_watermark_debug_stop(struct devfreq *df)
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{
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struct wmark_gov_info *wmarkinfo = df->data;
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debugfs_remove_recursive(wmarkinfo->debugdir);
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}
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static int devfreq_watermark_start(struct devfreq *df)
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{
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struct wmark_gov_info *wmarkinfo;
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struct platform_device *pdev = to_platform_device(df->dev.parent);
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if (!df->profile->freq_table) {
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dev_err(&pdev->dev, "Frequency table missing\n");
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return -EINVAL;
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}
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wmarkinfo = kzalloc(sizeof(struct wmark_gov_info), GFP_KERNEL);
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if (!wmarkinfo)
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return -ENOMEM;
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df->data = (void *)wmarkinfo;
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wmarkinfo->freqlist = df->profile->freq_table;
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wmarkinfo->freq_count = df->profile->max_state;
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wmarkinfo->p_load_target = 700;
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wmarkinfo->p_load_max = 900;
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wmarkinfo->df = df;
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wmarkinfo->pdev = pdev;
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devfreq_watermark_debug_start(df);
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return 0;
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}
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static int devfreq_watermark_event_handler(struct devfreq *df,
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unsigned int event, void *wmark_type)
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{
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int ret = 0;
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struct wmark_gov_info *wmarkinfo = df->data;
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switch (event) {
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case DEVFREQ_GOV_START:
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devfreq_watermark_start(df);
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wmarkinfo = df->data;
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update_watermarks(df, wmarkinfo->freqlist[0]);
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break;
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case DEVFREQ_GOV_STOP:
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devfreq_watermark_debug_stop(df);
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break;
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case DEVFREQ_GOV_SUSPEND:
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devfreq_monitor_suspend(df);
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break;
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case DEVFREQ_GOV_RESUME:
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wmarkinfo = df->data;
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update_watermarks(df, wmarkinfo->freqlist[0]);
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devfreq_monitor_resume(df);
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break;
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case DEVFREQ_GOV_WMARK:
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mutex_lock(&df->lock);
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update_devfreq(df);
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mutex_unlock(&df->lock);
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break;
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default:
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break;
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}
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return ret;
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}
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static struct devfreq_governor devfreq_watermark_active = {
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.name = "wmark_active",
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.get_target_freq = devfreq_watermark_target_freq,
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.event_handler = devfreq_watermark_event_handler,
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};
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static int __init devfreq_watermark_init(void)
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{
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return devfreq_add_governor(&devfreq_watermark_active);
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}
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static void __exit devfreq_watermark_exit(void)
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{
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devfreq_remove_governor(&devfreq_watermark_active);
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}
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rootfs_initcall(devfreq_watermark_init);
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module_exit(devfreq_watermark_exit);
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