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/*
* ARM big.LITTLE Platforms CPUFreq support
*
* Copyright (C) 2013 ARM Ltd.
* Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
*
* Copyright (C) 2013 Linaro.
* Viresh Kumar <viresh.kumar@linaro.org>
*
* 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.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/export.h>
#include <linux/of_platform.h>
#include <linux/opp.h>
#include <linux/slab.h>
#include <linux/topology.h>
#include <linux/types.h>
#include "arm_big_little.h"
/* Currently we support only two clusters */
#define MAX_CLUSTERS 2
static struct cpufreq_arm_bL_ops *arm_bL_ops;
static struct clk *clk[MAX_CLUSTERS];
static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS];
static atomic_t cluster_usage[MAX_CLUSTERS] = {ATOMIC_INIT(0), ATOMIC_INIT(0)};
static unsigned int bL_cpufreq_get(unsigned int cpu)
{
u32 cur_cluster = cpu_to_cluster(cpu);
return clk_get_rate(clk[cur_cluster]) / 1000;
}
/* Validate policy frequency range */
static int bL_cpufreq_verify_policy(struct cpufreq_policy *policy)
{
u32 cur_cluster = cpu_to_cluster(policy->cpu);
return cpufreq_frequency_table_verify(policy, freq_table[cur_cluster]);
}
/* Set clock frequency */
static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
struct cpufreq_freqs freqs;
u32 cpu = policy->cpu, freq_tab_idx, cur_cluster;
int ret = 0;
cur_cluster = cpu_to_cluster(policy->cpu);
freqs.old = bL_cpufreq_get(policy->cpu);
/* Determine valid target frequency using freq_table */
cpufreq_frequency_table_target(policy, freq_table[cur_cluster],
target_freq, relation, &freq_tab_idx);
freqs.new = freq_table[cur_cluster][freq_tab_idx].frequency;
pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
__func__, cpu, cur_cluster, freqs.old, target_freq,
freqs.new);
if (freqs.old == freqs.new)
return 0;
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
if (ret) {
pr_err("clk_set_rate failed: %d\n", ret);
freqs.new = freqs.old;
}
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
return ret;
}
static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
{
u32 cluster = cpu_to_cluster(cpu_dev->id);
if (!atomic_dec_return(&cluster_usage[cluster])) {
clk_put(clk[cluster]);
opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
}
}
static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
{
u32 cluster = cpu_to_cluster(cpu_dev->id);
char name[14] = "cpu-cluster.";
int ret;
if (atomic_inc_return(&cluster_usage[cluster]) != 1)
return 0;
ret = arm_bL_ops->init_opp_table(cpu_dev);
if (ret) {
dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
__func__, cpu_dev->id, ret);
goto atomic_dec;
}
ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
if (ret) {
dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
__func__, cpu_dev->id, ret);
goto atomic_dec;
}
name[12] = cluster + '0';
clk[cluster] = clk_get_sys(name, NULL);
if (!IS_ERR(clk[cluster])) {
dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
__func__, clk[cluster], freq_table[cluster],
cluster);
return 0;
}
dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
__func__, cpu_dev->id, cluster);
ret = PTR_ERR(clk[cluster]);
opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
atomic_dec:
atomic_dec(&cluster_usage[cluster]);
dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
cluster);
return ret;
}
/* Per-CPU initialization */
static int bL_cpufreq_init(struct cpufreq_policy *policy)
{
u32 cur_cluster = cpu_to_cluster(policy->cpu);
struct device *cpu_dev;
int ret;
cpu_dev = get_cpu_device(policy->cpu);
if (!cpu_dev) {
pr_err("%s: failed to get cpu%d device\n", __func__,
policy->cpu);
return -ENODEV;
}
ret = get_cluster_clk_and_freq_table(cpu_dev);
if (ret)
return ret;
ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
if (ret) {
dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
policy->cpu, cur_cluster);
put_cluster_clk_and_freq_table(cpu_dev);
return ret;
}
cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
if (arm_bL_ops->get_transition_latency)
policy->cpuinfo.transition_latency =
arm_bL_ops->get_transition_latency(cpu_dev);
else
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
policy->cur = bL_cpufreq_get(policy->cpu);
cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
return 0;
}
static int bL_cpufreq_exit(struct cpufreq_policy *policy)
{
struct device *cpu_dev;
cpu_dev = get_cpu_device(policy->cpu);
if (!cpu_dev) {
pr_err("%s: failed to get cpu%d device\n", __func__,
policy->cpu);
return -ENODEV;
}
put_cluster_clk_and_freq_table(cpu_dev);
dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
return 0;
}
/* Export freq_table to sysfs */
static struct freq_attr *bL_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver bL_cpufreq_driver = {
.name = "arm-big-little",
.flags = CPUFREQ_STICKY,
.verify = bL_cpufreq_verify_policy,
.target = bL_cpufreq_set_target,
.get = bL_cpufreq_get,
.init = bL_cpufreq_init,
.exit = bL_cpufreq_exit,
.have_governor_per_policy = true,
.attr = bL_cpufreq_attr,
};
int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
{
int ret;
if (arm_bL_ops) {
pr_debug("%s: Already registered: %s, exiting\n", __func__,
arm_bL_ops->name);
return -EBUSY;
}
if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
return -ENODEV;
}
arm_bL_ops = ops;
ret = cpufreq_register_driver(&bL_cpufreq_driver);
if (ret) {
pr_info("%s: Failed registering platform driver: %s, err: %d\n",
__func__, ops->name, ret);
arm_bL_ops = NULL;
} else {
pr_info("%s: Registered platform driver: %s\n", __func__,
ops->name);
}
return ret;
}
EXPORT_SYMBOL_GPL(bL_cpufreq_register);
void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
{
if (arm_bL_ops != ops) {
pr_err("%s: Registered with: %s, can't unregister, exiting\n",
__func__, arm_bL_ops->name);
return;
}
cpufreq_unregister_driver(&bL_cpufreq_driver);
pr_info("%s: Un-registered platform driver: %s\n", __func__,
arm_bL_ops->name);
arm_bL_ops = NULL;
}
EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);
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