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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/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
|