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/**
* Copyright (C) ARM Limited 2011-2012. 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 as
* published by the Free Software Foundation.
*
*/
#include "gator.h"
#include <linux/slab.h>
#include <linux/cpufreq.h>
#include <trace/events/power.h>
// cpu_frequency and cpu_idle trace points were introduced in Linux kernel v2.6.38
// the now deprecated power_frequency trace point was available prior to 2.6.38, but only for x86
// CPU Idle is currently disabled in the .xml
#if GATOR_CPU_FREQ_SUPPORT
enum {
POWER_CPU_FREQ,
POWER_CPU_IDLE,
POWER_TOTAL
};
static ulong power_cpu_enabled[POWER_TOTAL];
static ulong power_cpu_key[POWER_TOTAL];
static DEFINE_PER_CPU(ulong[POWER_TOTAL], power);
static DEFINE_PER_CPU(ulong[POWER_TOTAL], prev);
static DEFINE_PER_CPU(int *, powerGet);
GATOR_DEFINE_PROBE(cpu_frequency, TP_PROTO(unsigned int frequency, unsigned int cpu))
{
per_cpu(power, cpu)[POWER_CPU_FREQ] = frequency * 1000;
}
GATOR_DEFINE_PROBE(cpu_idle, TP_PROTO(unsigned int state, unsigned int cpu))
{
per_cpu(power, cpu)[POWER_CPU_IDLE] = state;
}
static int gator_events_power_create_files(struct super_block *sb, struct dentry *root)
{
struct dentry *dir;
// cpu_frequency
dir = gatorfs_mkdir(sb, root, "Linux_power_cpu_freq");
if (!dir) {
return -1;
}
gatorfs_create_ulong(sb, dir, "enabled", &power_cpu_enabled[POWER_CPU_FREQ]);
gatorfs_create_ro_ulong(sb, dir, "key", &power_cpu_key[POWER_CPU_FREQ]);
// cpu_idle
dir = gatorfs_mkdir(sb, root, "Linux_power_cpu_idle");
if (!dir) {
return -1;
}
gatorfs_create_ulong(sb, dir, "enabled", &power_cpu_enabled[POWER_CPU_IDLE]);
gatorfs_create_ro_ulong(sb, dir, "key", &power_cpu_key[POWER_CPU_IDLE]);
return 0;
}
static int gator_events_power_populate(int cpu, int** buffer)
{
int i, len = 0;
for (i = 0; i < POWER_TOTAL; i++) {
if (power_cpu_enabled[i]) {
if (per_cpu(power, cpu)[i] != per_cpu(prev, cpu)[i]) {
per_cpu(prev, cpu)[i] = per_cpu(power, cpu)[i];
per_cpu(powerGet, cpu)[len++] = power_cpu_key[i];
per_cpu(powerGet, cpu)[len++] = per_cpu(power, cpu)[i];
}
}
}
if (buffer)
*buffer = per_cpu(powerGet, cpu);
return len;
}
static int gator_events_power_online(int** buffer)
{
int i, cpu = smp_processor_id();
for (i = 0; i < POWER_TOTAL; i++)
per_cpu(prev, cpu)[i] = -1;
per_cpu(power, cpu)[POWER_CPU_FREQ] = cpufreq_quick_get(cpu) * 1000;
return gator_events_power_populate(cpu, buffer);
}
static int gator_events_power_offline(int** buffer)
{
int cpu = smp_processor_id();
// Set frequency to zero on an offline
per_cpu(power, cpu)[POWER_CPU_FREQ] = 0;
return gator_events_power_populate(cpu, buffer);
}
static int gator_events_power_start(void)
{
int cpu;
for_each_present_cpu(cpu) {
per_cpu(powerGet, cpu) = kmalloc(POWER_TOTAL * 2, GFP_KERNEL);
if (!per_cpu(powerGet, cpu))
return -1;
}
// register tracepoints
if (power_cpu_enabled[POWER_CPU_FREQ])
if (GATOR_REGISTER_TRACE(cpu_frequency))
goto fail_cpu_frequency_exit;
if (power_cpu_enabled[POWER_CPU_IDLE])
if (GATOR_REGISTER_TRACE(cpu_idle))
goto fail_cpu_idle_exit;
pr_debug("gator: registered power event tracepoints\n");
return 0;
// unregister tracepoints on error
fail_cpu_idle_exit:
GATOR_UNREGISTER_TRACE(cpu_frequency);
fail_cpu_frequency_exit:
pr_err("gator: power event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");
return -1;
}
static void gator_events_power_stop(void)
{
int i, cpu;
if (power_cpu_enabled[POWER_CPU_FREQ])
GATOR_UNREGISTER_TRACE(cpu_frequency);
if (power_cpu_enabled[POWER_CPU_IDLE])
GATOR_UNREGISTER_TRACE(cpu_idle);
pr_debug("gator: unregistered power event tracepoints\n");
for (i = 0; i < POWER_TOTAL; i++) {
power_cpu_enabled[i] = 0;
}
for_each_present_cpu(cpu) {
kfree(per_cpu(powerGet, cpu));
}
}
static int gator_events_power_read(int **buffer)
{
return gator_events_power_populate(smp_processor_id(), buffer);
}
static struct gator_interface gator_events_power_interface = {
.create_files = gator_events_power_create_files,
.online = gator_events_power_online,
.offline = gator_events_power_offline,
.start = gator_events_power_start,
.stop = gator_events_power_stop,
.read = gator_events_power_read,
};
#endif
int gator_events_power_init(void)
{
#if (GATOR_CPU_FREQ_SUPPORT)
int i;
for (i = 0; i < POWER_TOTAL; i++) {
power_cpu_enabled[i] = 0;
power_cpu_key[i] = gator_events_get_key();
}
return gator_events_install(&gator_events_power_interface);
#else
return -1;
#endif
}
gator_events_init(gator_events_power_init);
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