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// SPDX-License-Identifier: GPL-2.0+
/*
* CPUFreq support for Armada 8K
*
* Copyright (C) 2018 Marvell
*
* Omri Itach <omrii@marvell.com>
* Gregory Clement <gregory.clement@bootlin.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/slab.h>
/*
* Setup the opps list with the divider for the max frequency, that
* will be filled at runtime.
*/
static const int opps_div[] __initconst = {1, 2, 3, 4};
static struct platform_device *armada_8k_pdev;
struct freq_table {
struct device *cpu_dev;
unsigned int freq[ARRAY_SIZE(opps_div)];
};
/* If the CPUs share the same clock, then they are in the same cluster. */
static void __init armada_8k_get_sharing_cpus(struct clk *cur_clk,
struct cpumask *cpumask)
{
int cpu;
for_each_possible_cpu(cpu) {
struct device *cpu_dev;
struct clk *clk;
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
pr_warn("Failed to get cpu%d device\n", cpu);
continue;
}
clk = clk_get(cpu_dev, 0);
if (IS_ERR(clk)) {
pr_warn("Cannot get clock for CPU %d\n", cpu);
} else {
if (clk_is_match(clk, cur_clk))
cpumask_set_cpu(cpu, cpumask);
clk_put(clk);
}
}
}
static int __init armada_8k_add_opp(struct clk *clk, struct device *cpu_dev,
struct freq_table *freq_tables,
int opps_index)
{
unsigned int cur_frequency;
unsigned int freq;
int i, ret;
/* Get nominal (current) CPU frequency. */
cur_frequency = clk_get_rate(clk);
if (!cur_frequency) {
dev_err(cpu_dev, "Failed to get clock rate for this CPU\n");
return -EINVAL;
}
freq_tables[opps_index].cpu_dev = cpu_dev;
for (i = 0; i < ARRAY_SIZE(opps_div); i++) {
freq = cur_frequency / opps_div[i];
ret = dev_pm_opp_add(cpu_dev, freq, 0);
if (ret)
return ret;
freq_tables[opps_index].freq[i] = freq;
}
return 0;
}
static void armada_8k_cpufreq_free_table(struct freq_table *freq_tables)
{
int opps_index, nb_cpus = num_possible_cpus();
for (opps_index = 0 ; opps_index <= nb_cpus; opps_index++) {
int i;
/* If cpu_dev is NULL then we reached the end of the array */
if (!freq_tables[opps_index].cpu_dev)
break;
for (i = 0; i < ARRAY_SIZE(opps_div); i++) {
/*
* A 0Hz frequency is not valid, this meant
* that it was not yet initialized so there is
* no more opp to free
*/
if (freq_tables[opps_index].freq[i] == 0)
break;
dev_pm_opp_remove(freq_tables[opps_index].cpu_dev,
freq_tables[opps_index].freq[i]);
}
}
kfree(freq_tables);
}
static int __init armada_8k_cpufreq_init(void)
{
int ret = 0, opps_index = 0, cpu, nb_cpus;
struct freq_table *freq_tables;
struct device_node *node;
struct cpumask cpus;
node = of_find_compatible_node(NULL, NULL, "marvell,ap806-cpu-clock");
if (!node || !of_device_is_available(node)) {
of_node_put(node);
return -ENODEV;
}
nb_cpus = num_possible_cpus();
freq_tables = kcalloc(nb_cpus, sizeof(*freq_tables), GFP_KERNEL);
cpumask_copy(&cpus, cpu_possible_mask);
/*
* For each CPU, this loop registers the operating points
* supported (which are the nominal CPU frequency and full integer
* divisions of it).
*/
for_each_cpu(cpu, &cpus) {
struct cpumask shared_cpus;
struct device *cpu_dev;
struct clk *clk;
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
pr_err("Cannot get CPU %d\n", cpu);
continue;
}
clk = clk_get(cpu_dev, 0);
if (IS_ERR(clk)) {
pr_err("Cannot get clock for CPU %d\n", cpu);
ret = PTR_ERR(clk);
goto remove_opp;
}
ret = armada_8k_add_opp(clk, cpu_dev, freq_tables, opps_index);
if (ret) {
clk_put(clk);
goto remove_opp;
}
opps_index++;
cpumask_clear(&shared_cpus);
armada_8k_get_sharing_cpus(clk, &shared_cpus);
dev_pm_opp_set_sharing_cpus(cpu_dev, &shared_cpus);
cpumask_andnot(&cpus, &cpus, &shared_cpus);
clk_put(clk);
}
armada_8k_pdev = platform_device_register_simple("cpufreq-dt", -1,
NULL, 0);
ret = PTR_ERR_OR_ZERO(armada_8k_pdev);
if (ret)
goto remove_opp;
platform_set_drvdata(armada_8k_pdev, freq_tables);
return 0;
remove_opp:
armada_8k_cpufreq_free_table(freq_tables);
return ret;
}
module_init(armada_8k_cpufreq_init);
static void __exit armada_8k_cpufreq_exit(void)
{
struct freq_table *freq_tables = platform_get_drvdata(armada_8k_pdev);
platform_device_unregister(armada_8k_pdev);
armada_8k_cpufreq_free_table(freq_tables);
}
module_exit(armada_8k_cpufreq_exit);
MODULE_AUTHOR("Gregory Clement <gregory.clement@bootlin.com>");
MODULE_DESCRIPTION("Armada 8K cpufreq driver");
MODULE_LICENSE("GPL");
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