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/*
* Copyright (c) 2014-2016, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/devfreq.h>
#include <linux/module.h>
#include "governor.h"
unsigned long (*extern_get_bw)(void) = NULL;
unsigned long *dev_ab;
static unsigned long dev_ib;
DEFINE_MUTEX(df_lock);
static struct devfreq *df;
/*
* This function is 'get_target_freq' API for the governor.
* It just calls an external function that should be registered
* by KGSL driver to get and return a value for frequency.
*/
static int devfreq_vbif_get_freq(struct devfreq *df,
unsigned long *freq,
u32 *flag)
{
/* If the IB isn't set yet, check if it should be non-zero. */
if (!dev_ib && extern_get_bw) {
dev_ib = extern_get_bw();
if (dev_ab)
*dev_ab = dev_ib / 4;
}
*freq = dev_ib;
return 0;
}
/*
* Registers a function to be used to request a frequency
* value from legacy vbif based bus bandwidth governor.
* This function is called by KGSL driver.
*/
void devfreq_vbif_register_callback(void *p)
{
extern_get_bw = p;
}
int devfreq_vbif_update_bw(unsigned long ib, unsigned long ab)
{
int ret = 0;
mutex_lock(&df_lock);
if (df) {
mutex_lock(&df->lock);
dev_ib = ib;
*dev_ab = ab;
ret = update_devfreq(df);
mutex_unlock(&df->lock);
}
mutex_unlock(&df_lock);
return ret;
}
static int devfreq_vbif_ev_handler(struct devfreq *devfreq,
unsigned int event, void *data)
{
int ret;
struct devfreq_dev_status stat;
switch (event) {
case DEVFREQ_GOV_START:
mutex_lock(&df_lock);
df = devfreq;
if (df->profile->get_dev_status &&
!df->profile->get_dev_status(df->dev.parent, &stat) &&
stat.private_data)
dev_ab = stat.private_data;
else
pr_warn("Device doesn't take AB votes!\n");
mutex_unlock(&df_lock);
ret = devfreq_vbif_update_bw(0, 0);
if (ret) {
pr_err("Unable to update BW! Gov start failed!\n");
return ret;
}
/*
* Normally at this point governors start the polling with
* devfreq_monitor_start(df);
* This governor doesn't poll, but expect external calls
* of its devfreq_vbif_update_bw() function
*/
pr_debug("Enabled MSM VBIF governor\n");
break;
case DEVFREQ_GOV_STOP:
mutex_lock(&df_lock);
df = NULL;
mutex_unlock(&df_lock);
pr_debug("Disabled MSM VBIF governor\n");
break;
}
return 0;
}
static struct devfreq_governor devfreq_vbif = {
.name = "bw_vbif",
.get_target_freq = devfreq_vbif_get_freq,
.event_handler = devfreq_vbif_ev_handler,
};
static int __init devfreq_vbif_init(void)
{
return devfreq_add_governor(&devfreq_vbif);
}
subsys_initcall(devfreq_vbif_init);
static void __exit devfreq_vbif_exit(void)
{
int ret;
ret = devfreq_remove_governor(&devfreq_vbif);
if (ret)
pr_err("%s: failed remove governor %d\n", __func__, ret);
}
module_exit(devfreq_vbif_exit);
MODULE_DESCRIPTION("VBIF based GPU bus BW voting governor");
MODULE_LICENSE("GPL v2");
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