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authorGregory CLEMENT <gregory.clement@bootlin.com>2019-01-18 17:51:01 +0300
committerViresh Kumar <viresh.kumar@linaro.org>2019-02-07 07:31:51 +0300
commitf525a670533d961fd72ab748e3aac002d7b3d1b9 (patch)
treee39db50f572ce8f7f816410d6f9ddf69180522e5 /drivers/cpufreq/armada-8k-cpufreq.c
parent8e3151d16c7d8d3576fee23a6c898dd54ead4e0a (diff)
downloadlinux-f525a670533d961fd72ab748e3aac002d7b3d1b9.tar.xz
cpufreq: ap806: add cpufreq driver for Armada 8K
Add cpufreq driver for Marvell AP-806 found on Aramda 8K. The AP-806 has DFS (Dynamic Frequency Scaling) with coupled clock domain for two clusters, so this driver will directly use generic cpufreq-dt driver as backend. Based on the work of Omri Itach <omrii@marvell.com>. Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'drivers/cpufreq/armada-8k-cpufreq.c')
-rw-r--r--drivers/cpufreq/armada-8k-cpufreq.c204
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/cpufreq/armada-8k-cpufreq.c b/drivers/cpufreq/armada-8k-cpufreq.c
new file mode 100644
index 000000000000..8a5ddb93fc58
--- /dev/null
+++ b/drivers/cpufreq/armada-8k-cpufreq.c
@@ -0,0 +1,204 @@
+// 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))
+ 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");