Commit a0f950d3 authored by Sudeep Holla's avatar Sudeep Holla Committed by Viresh Kumar

cpufreq: merge arm_big_little and vexpress-spc

arm_big_little cpufreq driver was designed as a generic big little
driver that could be used by any platform and make use of bL switcher.
Over years alternate solutions have been designed and merged to deal
with bL/HMP systems like EAS.

Also since no other driver made use of generic arm_big_little cpufreq
driver except Vexpress SPC, we can merge them together as vexpress-spc
driver used only on Vexpress TC2(CA15_CA7) platform.
Acked-by: default avatarNicolas Pitre <nico@fluxnic.net>
Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent 1b82a4b5
...@@ -4273,14 +4273,13 @@ F: include/linux/cpufreq.h ...@@ -4273,14 +4273,13 @@ F: include/linux/cpufreq.h
F: include/linux/sched/cpufreq.h F: include/linux/sched/cpufreq.h
F: tools/testing/selftests/cpufreq/ F: tools/testing/selftests/cpufreq/
CPU FREQUENCY DRIVERS - ARM BIG LITTLE CPU FREQUENCY DRIVERS - VEXPRESS SPC ARM BIG LITTLE
M: Viresh Kumar <viresh.kumar@linaro.org> M: Viresh Kumar <viresh.kumar@linaro.org>
M: Sudeep Holla <sudeep.holla@arm.com> M: Sudeep Holla <sudeep.holla@arm.com>
L: linux-pm@vger.kernel.org L: linux-pm@vger.kernel.org
W: http://www.arm.com/products/processors/technologies/biglittleprocessing.php W: http://www.arm.com/products/processors/technologies/biglittleprocessing.php
S: Maintained S: Maintained
F: drivers/cpufreq/arm_big_little.h F: drivers/cpufreq/vexpress-spc-cpufreq.c
F: drivers/cpufreq/arm_big_little.c
CPU POWER MONITORING SUBSYSTEM CPU POWER MONITORING SUBSYSTEM
M: Thomas Renninger <trenn@suse.com> M: Thomas Renninger <trenn@suse.com>
......
...@@ -49,14 +49,6 @@ config ARM_ARMADA_8K_CPUFREQ ...@@ -49,14 +49,6 @@ config ARM_ARMADA_8K_CPUFREQ
If in doubt, say N. If in doubt, say N.
# big LITTLE core layer and glue drivers
config ARM_BIG_LITTLE_CPUFREQ
tristate "Generic ARM big LITTLE CPUfreq driver"
depends on ARM_CPU_TOPOLOGY && HAVE_CLK
select PM_OPP
help
This enables the Generic CPUfreq driver for ARM big.LITTLE platforms.
config ARM_SCPI_CPUFREQ config ARM_SCPI_CPUFREQ
tristate "SCPI based CPUfreq driver" tristate "SCPI based CPUfreq driver"
depends on ARM_SCPI_PROTOCOL && COMMON_CLK_SCPI depends on ARM_SCPI_PROTOCOL && COMMON_CLK_SCPI
...@@ -69,7 +61,9 @@ config ARM_SCPI_CPUFREQ ...@@ -69,7 +61,9 @@ config ARM_SCPI_CPUFREQ
config ARM_VEXPRESS_SPC_CPUFREQ config ARM_VEXPRESS_SPC_CPUFREQ
tristate "Versatile Express SPC based CPUfreq driver" tristate "Versatile Express SPC based CPUfreq driver"
depends on ARM_BIG_LITTLE_CPUFREQ && ARCH_VEXPRESS_SPC depends on ARM_CPU_TOPOLOGY && HAVE_CLK
depends on ARCH_VEXPRESS_SPC
select PM_OPP
help help
This add the CPUfreq driver support for Versatile Express This add the CPUfreq driver support for Versatile Express
big.LITTLE platforms using SPC for power management. big.LITTLE platforms using SPC for power management.
......
...@@ -47,8 +47,6 @@ obj-$(CONFIG_X86_SFI_CPUFREQ) += sfi-cpufreq.o ...@@ -47,8 +47,6 @@ obj-$(CONFIG_X86_SFI_CPUFREQ) += sfi-cpufreq.o
################################################################################## ##################################################################################
# ARM SoC drivers # ARM SoC drivers
obj-$(CONFIG_ARM_BIG_LITTLE_CPUFREQ) += arm_big_little.o
obj-$(CONFIG_ARM_ARMADA_37XX_CPUFREQ) += armada-37xx-cpufreq.o obj-$(CONFIG_ARM_ARMADA_37XX_CPUFREQ) += armada-37xx-cpufreq.o
obj-$(CONFIG_ARM_ARMADA_8K_CPUFREQ) += armada-8k-cpufreq.o obj-$(CONFIG_ARM_ARMADA_8K_CPUFREQ) += armada-8k-cpufreq.o
obj-$(CONFIG_ARM_BRCMSTB_AVS_CPUFREQ) += brcmstb-avs-cpufreq.o obj-$(CONFIG_ARM_BRCMSTB_AVS_CPUFREQ) += brcmstb-avs-cpufreq.o
......
/*
* 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/cpu_cooling.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 thermal_cooling_device *cdev[MAX_CLUSTERS];
static const 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;
int ret;
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;
}
}
ret = bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs_new);
if (!ret) {
arch_set_freq_scale(policy->related_cpus, freqs_new,
policy->cpuinfo.max_freq);
}
return ret;
}
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 = kcalloc(count, sizeof(*table), 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,
const struct cpumask *cpumask)
{
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(cpumask);
dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
}
static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
const struct cpumask *cpumask)
{
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, cpumask);
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, cpumask);
}
/* free virtual table */
kfree(freq_table[cluster]);
}
static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
const struct cpumask *cpumask)
{
u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
int ret;
if (freq_table[cluster])
return 0;
ret = arm_bL_ops->init_opp_table(cpumask);
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(cpumask);
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,
const struct cpumask *cpumask)
{
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, cpumask);
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, cpumask);
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, cpumask);
}
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;
}
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;
}
ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
if (ret)
return ret;
policy->freq_table = freq_table[cur_cluster];
policy->cpuinfo.transition_latency =
arm_bL_ops->get_transition_latency(cpu_dev);
dev_pm_opp_of_register_em(policy->cpus);
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;
int cur_cluster = cpu_to_cluster(policy->cpu);
if (cur_cluster < MAX_CLUSTERS) {
cpufreq_cooling_unregister(cdev[cur_cluster]);
cdev[cur_cluster] = NULL;
}
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, policy->related_cpus);
dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
return 0;
}
static void bL_cpufreq_ready(struct cpufreq_policy *policy)
{
int cur_cluster = cpu_to_cluster(policy->cpu);
/* Do not register a cpu_cooling device if we are in IKS mode */
if (cur_cluster >= MAX_CLUSTERS)
return;
cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
}
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,
.ready = bL_cpufreq_ready,
.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(const 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 ||
!ops->get_transition_latency) {
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(const 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");
/*
* ARM big.LITTLE platform's CPUFreq header file
*
* 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.
*/
#ifndef CPUFREQ_ARM_BIG_LITTLE_H
#define CPUFREQ_ARM_BIG_LITTLE_H
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/types.h>
struct cpufreq_arm_bL_ops {
char name[CPUFREQ_NAME_LEN];
/*
* This must set opp table for cpu_dev in a similar way as done by
* dev_pm_opp_of_add_table().
*/
int (*init_opp_table)(const struct cpumask *cpumask);
/* Optional */
int (*get_transition_latency)(struct device *cpu_dev);
void (*free_opp_table)(const struct cpumask *cpumask);
};
int bL_cpufreq_register(const struct cpufreq_arm_bL_ops *ops);
void bL_cpufreq_unregister(const struct cpufreq_arm_bL_ops *ops);
#endif /* CPUFREQ_ARM_BIG_LITTLE_H */
// SPDX-License-Identifier: GPL-2.0
/* /*
* Versatile Express SPC CPUFreq Interface driver * Versatile Express SPC CPUFreq Interface driver
* *
* It provides necessary ops to arm_big_little cpufreq driver. * Copyright (C) 2013 - 2019 ARM Ltd.
* Sudeep Holla <sudeep.holla@arm.com>
* *
* Copyright (C) 2013 ARM Ltd. * Copyright (C) 2013 Linaro.
* Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> * 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/cpu.h> #include <linux/cpu.h>
#include <linux/cpufreq.h> #include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/cpu_cooling.h>
#include <linux/device.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h> #include <linux/platform_device.h>
#include <linux/pm_opp.h> #include <linux/pm_opp.h>
#include <linux/slab.h>
#include <linux/topology.h>
#include <linux/types.h> #include <linux/types.h>
#include "arm_big_little.h" struct cpufreq_arm_bL_ops {
char name[CPUFREQ_NAME_LEN];
/*
* This must set opp table for cpu_dev in a similar way as done by
* dev_pm_opp_of_add_table().
*/
int (*init_opp_table)(const struct cpumask *cpumask);
/* Optional */
int (*get_transition_latency)(struct device *cpu_dev);
void (*free_opp_table)(const struct cpumask *cpumask);
};
/* 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 thermal_cooling_device *cdev[MAX_CLUSTERS];
static const 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;
int ret;
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;
}
}
ret = bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs_new);
if (!ret) {
arch_set_freq_scale(policy->related_cpus, freqs_new,
policy->cpuinfo.max_freq);
}
return ret;
}
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 = kcalloc(count, sizeof(*table), 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,
const struct cpumask *cpumask)
{
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(cpumask);
dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
}
static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
const struct cpumask *cpumask)
{
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, cpumask);
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, cpumask);
}
/* free virtual table */
kfree(freq_table[cluster]);
}
static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
const struct cpumask *cpumask)
{
u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
int ret;
if (freq_table[cluster])
return 0;
ret = arm_bL_ops->init_opp_table(cpumask);
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(cpumask);
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,
const struct cpumask *cpumask)
{
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, cpumask);
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, cpumask);
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, cpumask);
}
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;
}
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;
}
ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
if (ret)
return ret;
policy->freq_table = freq_table[cur_cluster];
policy->cpuinfo.transition_latency =
arm_bL_ops->get_transition_latency(cpu_dev);
dev_pm_opp_of_register_em(policy->cpus);
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;
int cur_cluster = cpu_to_cluster(policy->cpu);
if (cur_cluster < MAX_CLUSTERS) {
cpufreq_cooling_unregister(cdev[cur_cluster]);
cdev[cur_cluster] = NULL;
}
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, policy->related_cpus);
dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
return 0;
}
static void bL_cpufreq_ready(struct cpufreq_policy *policy)
{
int cur_cluster = cpu_to_cluster(policy->cpu);
/* Do not register a cpu_cooling device if we are in IKS mode */
if (cur_cluster >= MAX_CLUSTERS)
return;
cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
}
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,
.ready = bL_cpufreq_ready,
.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(const 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 ||
!ops->get_transition_latency) {
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;
}
void bL_cpufreq_unregister(const 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;
}
static int ve_spc_init_opp_table(const struct cpumask *cpumask) static int ve_spc_init_opp_table(const struct cpumask *cpumask)
{ {
...@@ -68,4 +697,7 @@ static struct platform_driver ve_spc_cpufreq_platdrv = { ...@@ -68,4 +697,7 @@ static struct platform_driver ve_spc_cpufreq_platdrv = {
}; };
module_platform_driver(ve_spc_cpufreq_platdrv); module_platform_driver(ve_spc_cpufreq_platdrv);
MODULE_LICENSE("GPL"); MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
MODULE_LICENSE("GPL v2");
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