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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;
- }
- of_node_put(node);
- nb_cpus = num_possible_cpus();
- freq_tables = kcalloc(nb_cpus, sizeof(*freq_tables), GFP_KERNEL);
- if (!freq_tables)
- return -ENOMEM;
- 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);
- static const struct of_device_id __maybe_unused armada_8k_cpufreq_of_match[] = {
- { .compatible = "marvell,ap806-cpu-clock" },
- { },
- };
- MODULE_DEVICE_TABLE(of, armada_8k_cpufreq_of_match);
- MODULE_AUTHOR("Gregory Clement <gregory.clement@bootlin.com>");
- MODULE_DESCRIPTION("Armada 8K cpufreq driver");
- MODULE_LICENSE("GPL");
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