diff options
Diffstat (limited to 'drivers/cpufreq/armada-8k-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/armada-8k-cpufreq.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/drivers/cpufreq/armada-8k-cpufreq.c b/drivers/cpufreq/armada-8k-cpufreq.c new file mode 100644 index 0000000000..8afefdea4d --- /dev/null +++ b/drivers/cpufreq/armada-8k-cpufreq.c @@ -0,0 +1,217 @@ +// 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> + +static const struct of_device_id __maybe_unused armada_8k_cpufreq_of_match[] = { + { .compatible = "marvell,ap806-cpu-clock" }, + { .compatible = "marvell,ap807-cpu-clock" }, + { }, +}; +MODULE_DEVICE_TABLE(of, armada_8k_cpufreq_of_match); + +/* + * 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_matching_node_and_match(NULL, armada_8k_cpufreq_of_match, + NULL); + 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); + +MODULE_AUTHOR("Gregory Clement <gregory.clement@bootlin.com>"); +MODULE_DESCRIPTION("Armada 8K cpufreq driver"); +MODULE_LICENSE("GPL"); |