rockbox/firmware/target/hosted/cpufreq-linux.c
Udo Schläpfer a312ca1c50 CPUFreq scaling governor interface for Linux/Android hosted devices.
For a usage example see http://gerrit.rockbox.org/r/#/c/1074/

Change-Id: I1d61e0eba6552a9b5d6e15a2e3169435b2f7079d
2015-01-30 20:15:58 +01:00

151 lines
3.7 KiB
C

/***************************************************************************
* __________ __ ___
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
*
* Copyright (C) 2015 by Udo Schläpfer
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stdio.h>
#include <string.h>
#include "config.h"
#include "cpuinfo-linux.h"
#include "debug.h"
#include "cpufreq-linux.h"
static FILE* open_read(const char* file_name)
{
FILE *f = fopen(file_name, "r");
if(f == NULL)
{
DEBUGF("ERROR %s: Can not open %s for reading.", __func__, file_name);
}
return f;
}
void cpufreq_available_governors(char* governors, int governors_size, int cpu)
{
if(governors_size <= 0)
{
DEBUGF("ERROR %s: Invalid governors_size: %d.", __func__, governors_size);
return;
}
if(cpu < 0)
{
DEBUGF("ERROR %s: Invalid cpu: %d.", __func__, cpu);
return;
}
char available_governors_interface[70];
snprintf(available_governors_interface,
sizeof(available_governors_interface),
"/sys/devices/system/cpu/cpu%d/cpufreq/scaling_available_governors",
cpu);
FILE *f = open_read(available_governors_interface);
if(f == NULL)
{
return;
}
if(fgets(governors, governors_size, f) == NULL)
{
DEBUGF("ERROR %s: Read failed for %s.", __func__, available_governors_interface);
fclose(f);
return;
}
DEBUGF("DEBUG %s: Available governors for cpu %d: %s.", __func__, cpu, governors);
fclose(f);
}
static FILE* open_write(const char* file_name)
{
FILE *f = fopen(file_name, "w");
if(f == NULL)
{
DEBUGF("ERROR %s: Can not open %s for writing.", __func__, file_name);
}
return f;
}
static void set_governor_for_cpu(const char* governor, int cpu)
{
DEBUGF("DEBUG %s: governor: %s, cpu: %d.", __func__, governor, cpu);
char scaling_governor_interface[64];
snprintf(scaling_governor_interface,
sizeof(scaling_governor_interface),
"/sys/devices/system/cpu/cpu%d/cpufreq/scaling_governor",
cpu);
FILE *f = open_write(scaling_governor_interface);
if(f == NULL)
{
return;
}
if(fprintf(f, "%s", governor) < 1)
{
DEBUGF("ERROR %s: Write failed for %s.", __func__, scaling_governor_interface);
}
fclose(f);
}
void cpufreq_set_governor(const char* governor, int cpu)
{
if(governor == NULL)
{
DEBUGF("ERROR %s: Invalid governor.", __func__);
return;
}
if(cpu < CPUFREQ_ALL_CPUS)
{
DEBUGF("ERROR %s: Invalid cpu: %d.", __func__, cpu);
return;
}
DEBUGF("DEBUG %s: governor: %s, cpu: %d.", __func__, governor, cpu);
if(cpu == CPUFREQ_ALL_CPUS)
{
int max_cpu = cpucount_linux();
for(int count = 0; count < max_cpu; ++count)
{
set_governor_for_cpu(governor, count);
}
}
else
{
set_governor_for_cpu(governor, cpu);
}
}