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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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b8004afbcb
This governor should be used by KGSL driver to vote for msm bus bandwidth using devbw devices. KGSL driver needs to register a callback function that returns required IB value, and call devfreq_vbif_update_bw() function any time it want to vote for bus bandwidth. Change-Id: I6c7c08b7c3255b3793f1868d9cde604175093145 Signed-off-by: Vladimir Razgulin <vrazguli@codeaurora.org>
129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
/*
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* Copyright (c) 2014, The Linux Foundation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 and
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* only version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/devfreq.h>
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#include <linux/module.h>
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#include "governor.h"
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unsigned long (*extern_get_bw)(void) = NULL;
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DEFINE_MUTEX(df_lock);
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static struct devfreq *df;
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/*
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* This function is 'get_target_freq' API for the governor.
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* It just calls an external function that should be registered
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* by KGSL driver to get and return a value for frequency.
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*/
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static int devfreq_vbif_get_freq(struct devfreq *df,
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unsigned long *freq,
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u32 *flag)
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{
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if (extern_get_bw) {
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*freq = extern_get_bw();
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return 0;
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} else {
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return -ENODEV;
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}
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}
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/*
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* Registers a function to be used to request a frequency
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* value from legacy vbif based bus bandwidth governor.
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* This function is called by KGSL driver.
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*/
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void devfreq_vbif_register_callback(void *p)
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{
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extern_get_bw = p;
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}
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int devfreq_vbif_update_bw(void)
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{
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int ret = 0;
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mutex_lock(&df_lock);
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if (df) {
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mutex_lock(&df->lock);
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ret = update_devfreq(df);
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mutex_unlock(&df->lock);
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}
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mutex_unlock(&df_lock);
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return ret;
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}
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static int devfreq_vbif_ev_handler(struct devfreq *devfreq,
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unsigned int event, void *data)
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{
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int ret;
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switch (event) {
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case DEVFREQ_GOV_START:
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mutex_lock(&df_lock);
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df = devfreq;
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mutex_unlock(&df_lock);
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ret = devfreq_vbif_update_bw();
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if (ret) {
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pr_err("Unable to update BW! Gov start failed!\n");
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return ret;
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}
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/*
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* Normally at this point governors start the polling with
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* devfreq_monitor_start(df);
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* This governor doesn't poll, but expect external calls
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* of its devfreq_vbif_update_bw() function
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*/
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pr_debug("Enabled MSM VBIF governor\n");
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break;
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case DEVFREQ_GOV_STOP:
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mutex_lock(&df_lock);
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df = NULL;
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mutex_unlock(&df_lock);
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pr_debug("Disabled MSM VBIF governor\n");
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break;
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}
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return 0;
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}
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static struct devfreq_governor devfreq_vbif = {
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.name = "bw_vbif",
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.get_target_freq = devfreq_vbif_get_freq,
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.event_handler = devfreq_vbif_ev_handler,
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};
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static int __init devfreq_vbif_init(void)
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{
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return devfreq_add_governor(&devfreq_vbif);
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}
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subsys_initcall(devfreq_vbif_init);
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static void __exit devfreq_vbif_exit(void)
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{
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int ret;
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ret = devfreq_remove_governor(&devfreq_vbif);
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if (ret)
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pr_err("%s: failed remove governor %d\n", __func__, ret);
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return;
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}
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module_exit(devfreq_vbif_exit);
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MODULE_DESCRIPTION("VBIF based GPU bus BW voting governor");
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MODULE_LICENSE("GPL v2");
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