- 根目录:
- drivers
- cpufreq
- arm_big_little.c
/*
* 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/module.h>
#include <linux/mutex.h>
#include <linux/of_platform.h>
#include <linux/pm_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 A15_CLUSTER 0
#define A7_CLUSTER 1
#define MAX_CLUSTERS 2
#ifdef CONFIG_BL_SWITCHER
#include <asm/bL_switcher.h>
static bool bL_switching_enabled;
#define is_bL_switching_enabled() bL_switching_enabled
#define set_switching_enabled(x) (bL_switching_enabled = (x))
#else
#define is_bL_switching_enabled() false
#define set_switching_enabled(x) do { } while (0)
#define bL_switch_request(...) do { } while (0)
#define bL_switcher_put_enabled() do { } while (0)
#define bL_switcher_get_enabled() do { } while (0)
#endif
#define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq)
#define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
static struct cpufreq_arm_bL_ops *arm_bL_ops;
static struct clk *clk[MAX_CLUSTERS];
static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
static atomic_t cluster_usage[MAX_CLUSTERS + 1];
static unsigned int clk_big_min; /* (Big) clock frequencies */
static unsigned int clk_little_max; /* Maximum clock frequency (Little) */
static DEFINE_PER_CPU(unsigned int, physical_cluster);
static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
static struct mutex cluster_lock[MAX_CLUSTERS];
static inline int raw_cpu_to_cluster(int cpu)
{
return topology_physical_package_id(cpu);
}
static inline int cpu_to_cluster(int cpu)
{
return is_bL_switching_enabled() ?
MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
}
static unsigned int find_cluster_maxfreq(int cluster)
{
int j;
u32 max_freq = 0, cpu_freq;
for_each_online_cpu(j) {
cpu_freq = per_cpu(cpu_last_req_freq, j);
if ((cluster == per_cpu(physical_cluster, j)) &&
(max_freq < cpu_freq))
max_freq = cpu_freq;
}
pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster,
max_freq);
return max_freq;
}
static unsigned int clk_get_cpu_rate(unsigned int cpu)
{
u32 cur_cluster = per_cpu(physical_cluster, cpu);
u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
/* For switcher we use virtual A7 clock rates */
if (is_bL_switching_enabled())
rate = VIRT_FREQ(cur_cluster, rate);
pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu,
cur_cluster, rate);
return rate;
}
static unsigned int bL_cpufreq_get_rate(unsigned int cpu)
{
if (is_bL_switching_enabled()) {
pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq,
cpu));
return per_cpu(cpu_last_req_freq, cpu);
} else {
return clk_get_cpu_rate(cpu);
}
}
static unsigned int
bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
{
u32 new_rate, prev_rate;
int ret;
bool bLs = is_bL_switching_enabled();
mutex_lock(&cluster_lock[new_cluster]);
if (bLs) {
prev_rate = per_cpu(cpu_last_req_freq, cpu);
per_cpu(cpu_last_req_freq, cpu) = rate;
per_cpu(physical_cluster, cpu) = new_cluster;
new_rate = find_cluster_maxfreq(new_cluster);
new_rate = ACTUAL_FREQ(new_cluster, new_rate);
} else {
new_rate = rate;
}
pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
__func__, cpu, old_cluster, new_cluster, new_rate);
ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
if (!ret) {
/*
* FIXME: clk_set_rate hasn't returned an error here however it
* may be that clk_change_rate failed due to hardware or
* firmware issues and wasn't able to report that due to the
* current design of the clk core layer. To work around this
* problem we will read back the clock rate and check it is
* correct. This needs to be removed once clk core is fixed.
*/
if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
ret = -EIO;
}
if (WARN_ON(ret)) {
pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
new_cluster);
if (bLs) {
per_cpu(cpu_last_req_freq, cpu) = prev_rate;
per_cpu(physical_cluster, cpu) = old_cluster;
}
mutex_unlock(&cluster_lock[new_cluster]);
return ret;
}
mutex_unlock(&cluster_lock[new_cluster]);
/* Recalc freq for old cluster when switching clusters */
if (old_cluster != new_cluster) {
pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n",
__func__, cpu, old_cluster, new_cluster);
/* Switch cluster */
bL_switch_request(cpu, new_cluster);
mutex_lock(&cluster_lock[old_cluster]);
/* Set freq of old cluster if there are cpus left on it */
new_rate = find_cluster_maxfreq(old_cluster);
new_rate = ACTUAL_FREQ(old_cluster, new_rate);
if (new_rate) {
pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n",
__func__, old_cluster, new_rate);
if (clk_set_rate(clk[old_cluster], new_rate * 1000))
pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
__func__, ret, old_cluster);
}
mutex_unlock(&cluster_lock[old_cluster]);
}
return 0;
}
/* Set clock frequency */
static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int index)
{
u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
unsigned int freqs_new;
cur_cluster = cpu_to_cluster(cpu);
new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
freqs_new = freq_table[cur_cluster][index].frequency;
if (is_bL_switching_enabled()) {
if ((actual_cluster == A15_CLUSTER) &&
(freqs_new < clk_big_min)) {
new_cluster = A7_CLUSTER;
} else if ((actual_cluster == A7_CLUSTER) &&
(freqs_new > clk_little_max)) {
new_cluster = A15_CLUSTER;
}
}
return bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs_new);
}
static inline u32 get_table_count(struct cpufreq_frequency_table *table)
{
int count;
for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
;
return count;
}
/* get the minimum frequency in the cpufreq_frequency_table */
static inline u32 get_table_min(struct cpufreq_frequency_table *table)
{
struct cpufreq_frequency_table *pos;
uint32_t min_freq = ~0;
cpufreq_for_each_entry(pos, table)
if (pos->frequency < min_freq)
min_freq = pos->frequency;
return min_freq;
}
/* get the maximum frequency in the cpufreq_frequency_table */
static inline u32 get_table_max(struct cpufreq_frequency_table *table)
{
struct cpufreq_frequency_table *pos;
uint32_t max_freq = 0;
cpufreq_for_each_entry(pos, table)
if (pos->frequency > max_freq)
max_freq = pos->frequency;
return max_freq;
}
static int merge_cluster_tables(void)
{
int i, j, k = 0, count = 1;
struct cpufreq_frequency_table *table;
for (i = 0; i < MAX_CLUSTERS; i++)
count += get_table_count(freq_table[i]);
table = kzalloc(sizeof(*table) * count, GFP_KERNEL);
if (!table)
return -ENOMEM;
freq_table[MAX_CLUSTERS] = table;
/* Add in reverse order to get freqs in increasing order */
for (i = MAX_CLUSTERS - 1; i >= 0; i--) {
for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
j++) {
table[k].frequency = VIRT_FREQ(i,
freq_table[i][j].frequency);
pr_debug("%s: index: %d, freq: %d\n", __func__, k,
table[k].frequency);
k++;
}
}
table[k].driver_data = k;
table[k].frequency = CPUFREQ_TABLE_END;
pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k);
return 0;
}
static void _put_cluster_clk_and_freq_table(struct device *cpu_dev)
{
u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
if (!freq_table[cluster])
return;
clk_put(clk[cluster]);
dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
if (arm_bL_ops->free_opp_table)
arm_bL_ops->free_opp_table(cpu_dev);
dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
}
static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
{
u32 cluster = cpu_to_cluster(cpu_dev->id);
int i;
if (atomic_dec_return(&cluster_usage[cluster]))
return;
if (cluster < MAX_CLUSTERS)
return _put_cluster_clk_and_freq_table(cpu_dev);
for_each_present_cpu(i) {
struct device *cdev = get_cpu_device(i);
if (!cdev) {
pr_err("%s: failed to get cpu%d device\n", __func__, i);
return;
}
_put_cluster_clk_and_freq_table(cdev);
}
/* free virtual table */
kfree(freq_table[cluster]);
}
static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
{
u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
int ret;
if (freq_table[cluster])
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 out;
}
ret = dev_pm_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 free_opp_table;
}
clk[cluster] = clk_get(cpu_dev, 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]);
dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
free_opp_table:
if (arm_bL_ops->free_opp_table)
arm_bL_ops->free_opp_table(cpu_dev);
out:
dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
cluster);
return ret;
}
static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
{
u32 cluster = cpu_to_cluster(cpu_dev->id);
int i, ret;
if (atomic_inc_return(&cluster_usage[cluster]) != 1)
return 0;
if (cluster < MAX_CLUSTERS) {
ret = _get_cluster_clk_and_freq_table(cpu_dev);
if (ret)
atomic_dec(&cluster_usage[cluster]);
return ret;
}
/*
* Get data for all clusters and fill virtual cluster with a merge of
* both
*/
for_each_present_cpu(i) {
struct device *cdev = get_cpu_device(i);
if (!cdev) {
pr_err("%s: failed to get cpu%d device\n", __func__, i);
return -ENODEV;
}
ret = _get_cluster_clk_and_freq_table(cdev);
if (ret)
goto put_clusters;
}
ret = merge_cluster_tables();
if (ret)
goto put_clusters;
/* Assuming 2 cluster, set clk_big_min and clk_little_max */
clk_big_min = get_table_min(freq_table[0]);
clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
__func__, cluster, clk_big_min, clk_little_max);
return 0;
put_clusters:
for_each_present_cpu(i) {
struct device *cdev = get_cpu_device(i);
if (!cdev) {
pr_err("%s: failed to get cpu%d device\n", __func__, i);
return -ENODEV;
}
_put_cluster_clk_and_freq_table(cdev);
}
atomic_dec(&cluster_usage[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_table_validate_and_show(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;
}
if (cur_cluster < MAX_CLUSTERS) {
int cpu;
cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
for_each_cpu(cpu, policy->cpus)
per_cpu(physical_cluster, cpu) = cur_cluster;
} else {
/* Assumption: during init, we are always running on A15 */
per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
}
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;
if (is_bL_switching_enabled())
per_cpu(cpu_last_req_freq, policy->cpu) = clk_get_cpu_rate(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;
}
static struct cpufreq_driver bL_cpufreq_driver = {
.name = "arm-big-little",
.flags = CPUFREQ_STICKY |
CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = bL_cpufreq_set_target,
.get = bL_cpufreq_get_rate,
.init = bL_cpufreq_init,
.exit = bL_cpufreq_exit,
.attr = cpufreq_generic_attr,
};
#ifdef CONFIG_BL_SWITCHER
static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
unsigned long action, void *_arg)
{
pr_debug("%s: action: %ld\n", __func__, action);
switch (action) {
case BL_NOTIFY_PRE_ENABLE:
case BL_NOTIFY_PRE_DISABLE:
cpufreq_unregister_driver(&bL_cpufreq_driver);
break;
case BL_NOTIFY_POST_ENABLE:
set_switching_enabled(true);
cpufreq_register_driver(&bL_cpufreq_driver);
break;
case BL_NOTIFY_POST_DISABLE:
set_switching_enabled(false);
cpufreq_register_driver(&bL_cpufreq_driver);
break;
default:
return NOTIFY_DONE;
}
return NOTIFY_OK;
}
static struct notifier_block bL_switcher_notifier = {
.notifier_call = bL_cpufreq_switcher_notifier,
};
static int __bLs_register_notifier(void)
{
return bL_switcher_register_notifier(&bL_switcher_notifier);
}
static int __bLs_unregister_notifier(void)
{
return bL_switcher_unregister_notifier(&bL_switcher_notifier);
}
#else
static int __bLs_register_notifier(void) { return 0; }
static int __bLs_unregister_notifier(void) { return 0; }
#endif
int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
{
int ret, i;
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;
set_switching_enabled(bL_switcher_get_enabled());
for (i = 0; i < MAX_CLUSTERS; i++)
mutex_init(&cluster_lock[i]);
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 {
ret = __bLs_register_notifier();
if (ret) {
cpufreq_unregister_driver(&bL_cpufreq_driver);
arm_bL_ops = NULL;
} else {
pr_info("%s: Registered platform driver: %s\n",
__func__, ops->name);
}
}
bL_switcher_put_enabled();
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;
}
bL_switcher_get_enabled();
__bLs_unregister_notifier();
cpufreq_unregister_driver(&bL_cpufreq_driver);
bL_switcher_put_enabled();
pr_info("%s: Un-registered platform driver: %s\n", __func__,
arm_bL_ops->name);
arm_bL_ops = NULL;
}
EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);
MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver");
MODULE_LICENSE("GPL v2");