tempcpufreq/foo

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

3 files changed, 384 insertions, 0 deletions

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 2a84fc63371e..68f640c7b7a9 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -227,6 +227,17 @@ config CPUFREQ_DT_PLATDEV
 
 	  If in doubt, say N.
 
+config CPUFREQ_FOO
+	tristate "Generic Foo cpufreq driver"
+	select PM_OPP
+	default n
+	help
+	  This adds a foo-cpufreq driver, which can be used to stress various
+	  configurations of frequency switching algorithms on platform
+	  independent environments, like QEMU.
+
+	  If in doubt, say N.
+
 if X86
 source "drivers/cpufreq/Kconfig.x86"
 endif
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 32a7029e25ed..b9b9e866f287 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_ATTR_SET)	+= cpufreq_governor_attr_set.o
 
 obj-$(CONFIG_CPUFREQ_DT)		+= cpufreq-dt.o
 obj-$(CONFIG_CPUFREQ_DT_PLATDEV)	+= cpufreq-dt-platdev.o
+obj-$(CONFIG_CPUFREQ_FOO)		+= cpufreq-foo.o
 
 # Traces
 CFLAGS_amd-pstate-trace.o               := -I$(src)
diff --git a/drivers/cpufreq/cpufreq-foo.c b/drivers/cpufreq/cpufreq-foo.c
new file mode 100644
index 000000000000..bf7093da6ade
--- /dev/null
+++ b/drivers/cpufreq/cpufreq-foo.c
@@ -0,0 +1,372 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * A foo-cpufreq driver, which can be used to stress various configurations of
+ * frequency switching algorithms on platform independent environments, like
+ * QEMU.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+#include "cpufreq-dt.h"
+
+struct private_data {
+	struct list_head node;
+
+	cpumask_var_t cpus;
+	struct device *cpu_dev;
+	struct cpufreq_frequency_table *freq_table;
+	bool have_static_opps;
+	int opp_token;
+};
+
+static LIST_HEAD(priv_list);
+
+static struct freq_attr *cpufreq_dt_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,   /* Extra space for boost-attr if required */
+	NULL,
+};
+
+static struct private_data *cpufreq_dt_find_data(int cpu)
+{
+	struct private_data *priv;
+
+	list_for_each_entry(priv, &priv_list, node) {
+		if (cpumask_test_cpu(cpu, priv->cpus))
+			return priv;
+	}
+
+	return NULL;
+}
+
+static int set_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	struct private_data *priv = policy->driver_data;
+	unsigned long freq = policy->freq_table[index].frequency;
+
+	return dev_pm_opp_set_rate(priv->cpu_dev, freq * 1000);
+}
+
+/*
+ * An earlier version of opp-v1 bindings used to name the regulator
+ * "cpu0-supply", we still need to handle that for backwards compatibility.
+ */
+static const char *find_supply_name(struct device *dev)
+{
+	struct device_node *np;
+	struct property *pp;
+	int cpu = dev->id;
+	const char *name = NULL;
+
+	np = of_node_get(dev->of_node);
+
+	/* This must be valid for sure */
+	if (WARN_ON(!np))
+		return NULL;
+
+	/* Try "cpu0" for older DTs */
+	if (!cpu) {
+		pp = of_find_property(np, "cpu0-supply", NULL);
+		if (pp) {
+			name = "cpu0";
+			goto node_put;
+		}
+	}
+
+	pp = of_find_property(np, "cpu-supply", NULL);
+	if (pp) {
+		name = "cpu";
+		goto node_put;
+	}
+
+	dev_dbg(dev, "no regulator for cpu%d\n", cpu);
+node_put:
+	of_node_put(np);
+	return name;
+}
+
+static int cpufreq_init(struct cpufreq_policy *policy)
+{
+	struct private_data *priv;
+	struct device *cpu_dev;
+	struct clk *cpu_clk;
+	unsigned int transition_latency;
+	int ret;
+
+	priv = cpufreq_dt_find_data(policy->cpu);
+	if (!priv) {
+		pr_err("failed to find data for cpu%d\n", policy->cpu);
+		return -ENODEV;
+	}
+	cpu_dev = priv->cpu_dev;
+
+	cpu_clk = clk_get(cpu_dev, NULL);
+	if (IS_ERR(cpu_clk)) {
+		ret = PTR_ERR(cpu_clk);
+		dev_err(cpu_dev, "%s: failed to get clk: %d\n", __func__, ret);
+		return ret;
+	}
+
+	transition_latency = dev_pm_opp_get_max_transition_latency(cpu_dev);
+	if (!transition_latency)
+		transition_latency = CPUFREQ_ETERNAL;
+
+	cpumask_copy(policy->cpus, priv->cpus);
+	policy->driver_data = priv;
+	policy->clk = cpu_clk;
+	policy->freq_table = priv->freq_table;
+	policy->suspend_freq = dev_pm_opp_get_suspend_opp_freq(cpu_dev) / 1000;
+	policy->cpuinfo.transition_latency = transition_latency;
+	policy->dvfs_possible_from_any_cpu = true;
+
+	/* Support turbo/boost mode */
+	if (policy_has_boost_freq(policy)) {
+		/* This gets disabled by core on driver unregister */
+		ret = cpufreq_enable_boost_support();
+		if (ret)
+			goto out_clk_put;
+		cpufreq_dt_attr[1] = &cpufreq_freq_attr_scaling_boost_freqs;
+	}
+
+	return 0;
+
+out_clk_put:
+	clk_put(cpu_clk);
+
+	return ret;
+}
+
+static int cpufreq_online(struct cpufreq_policy *policy)
+{
+	/* We did light-weight tear down earlier, nothing to do here */
+	return 0;
+}
+
+static int cpufreq_offline(struct cpufreq_policy *policy)
+{
+	/*
+	 * Preserve policy->driver_data and don't free resources on light-weight
+	 * tear down.
+	 */
+	return 0;
+}
+
+static int cpufreq_exit(struct cpufreq_policy *policy)
+{
+	clk_put(policy->clk);
+	return 0;
+}
+
+static struct cpufreq_driver dt_cpufreq_driver = {
+	.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK |
+		 CPUFREQ_IS_COOLING_DEV,
+	.verify = cpufreq_generic_frequency_table_verify,
+	.target_index = set_target,
+	.get = cpufreq_generic_get,
+	.init = cpufreq_init,
+	.exit = cpufreq_exit,
+	.online = cpufreq_online,
+	.offline = cpufreq_offline,
+	.register_em = cpufreq_register_em_with_opp,
+	.name = "cpufreq-dt",
+	.attr = cpufreq_dt_attr,
+	.suspend = cpufreq_generic_suspend,
+};
+
+static int dt_cpufreq_early_init(struct device *dev, int cpu)
+{
+	struct private_data *priv;
+	struct device *cpu_dev;
+	bool fallback = false;
+	const char *reg_name[] = { NULL, NULL };
+	int ret;
+
+	/* Check if this CPU is already covered by some other policy */
+	if (cpufreq_dt_find_data(cpu))
+		return 0;
+
+	cpu_dev = get_cpu_device(cpu);
+	if (!cpu_dev)
+		return -EPROBE_DEFER;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	if (!alloc_cpumask_var(&priv->cpus, GFP_KERNEL))
+		return -ENOMEM;
+
+	cpumask_set_cpu(cpu, priv->cpus);
+	priv->cpu_dev = cpu_dev;
+
+	/*
+	 * OPP layer will be taking care of regulators now, but it needs to know
+	 * the name of the regulator first.
+	 */
+	reg_name[0] = find_supply_name(cpu_dev);
+	if (reg_name[0]) {
+		priv->opp_token = dev_pm_opp_set_regulators(cpu_dev, reg_name);
+		if (priv->opp_token < 0) {
+			ret = dev_err_probe(cpu_dev, priv->opp_token,
+					    "failed to set regulators\n");
+			goto free_cpumask;
+		}
+	}
+
+	/* Get OPP-sharing information from "operating-points-v2" bindings */
+	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->cpus);
+	if (ret) {
+		if (ret != -ENOENT)
+			goto out;
+
+		/*
+		 * operating-points-v2 not supported, fallback to all CPUs share
+		 * OPP for backward compatibility if the platform hasn't set
+		 * sharing CPUs.
+		 */
+		if (dev_pm_opp_get_sharing_cpus(cpu_dev, priv->cpus))
+			fallback = true;
+	}
+
+	/*
+	 * Initialize OPP tables for all priv->cpus. They will be shared by
+	 * all CPUs which have marked their CPUs shared with OPP bindings.
+	 *
+	 * For platforms not using operating-points-v2 bindings, we do this
+	 * before updating priv->cpus. Otherwise, we will end up creating
+	 * duplicate OPPs for the CPUs.
+	 *
+	 * OPPs might be populated at runtime, don't fail for error here unless
+	 * it is -EPROBE_DEFER.
+	 */
+	ret = dev_pm_opp_of_cpumask_add_table(priv->cpus);
+	if (!ret) {
+		priv->have_static_opps = true;
+	} else if (ret == -EPROBE_DEFER) {
+		goto out;
+	}
+
+	/*
+	 * The OPP table must be initialized, statically or dynamically, by this
+	 * point.
+	 */
+	ret = dev_pm_opp_get_opp_count(cpu_dev);
+	if (ret <= 0) {
+		dev_err(cpu_dev, "OPP table can't be empty\n");
+		ret = -ENODEV;
+		goto out;
+	}
+
+	if (fallback) {
+		cpumask_setall(priv->cpus);
+		ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->cpus);
+		if (ret)
+			dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
+				__func__, ret);
+	}
+
+	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &priv->freq_table);
+	if (ret) {
+		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
+		goto out;
+	}
+
+	list_add(&priv->node, &priv_list);
+	return 0;
+
+out:
+	if (priv->have_static_opps)
+		dev_pm_opp_of_cpumask_remove_table(priv->cpus);
+	dev_pm_opp_put_regulators(priv->opp_token);
+free_cpumask:
+	free_cpumask_var(priv->cpus);
+	return ret;
+}
+
+static void dt_cpufreq_release(void)
+{
+	struct private_data *priv, *tmp;
+
+	list_for_each_entry_safe(priv, tmp, &priv_list, node) {
+		dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &priv->freq_table);
+		if (priv->have_static_opps)
+			dev_pm_opp_of_cpumask_remove_table(priv->cpus);
+		dev_pm_opp_put_regulators(priv->opp_token);
+		free_cpumask_var(priv->cpus);
+		list_del(&priv->node);
+	}
+}
+
+static int dt_cpufreq_probe(struct platform_device *pdev)
+{
+	struct cpufreq_dt_platform_data *data = dev_get_platdata(&pdev->dev);
+	int ret, cpu;
+
+	/* Request resources early so we can return in case of -EPROBE_DEFER */
+	for_each_possible_cpu(cpu) {
+		ret = dt_cpufreq_early_init(&pdev->dev, cpu);
+		if (ret)
+			goto err;
+	}
+
+	if (data) {
+		if (data->have_governor_per_policy)
+			dt_cpufreq_driver.flags |= CPUFREQ_HAVE_GOVERNOR_PER_POLICY;
+
+		dt_cpufreq_driver.resume = data->resume;
+		if (data->suspend)
+			dt_cpufreq_driver.suspend = data->suspend;
+		if (data->get_intermediate) {
+			dt_cpufreq_driver.target_intermediate = data->target_intermediate;
+			dt_cpufreq_driver.get_intermediate = data->get_intermediate;
+		}
+	}
+
+	ret = cpufreq_register_driver(&dt_cpufreq_driver);
+	if (ret) {
+		dev_err(&pdev->dev, "failed register driver: %d\n", ret);
+		goto err;
+	}
+
+	return 0;
+err:
+	dt_cpufreq_release();
+	return ret;
+}
+
+static int dt_cpufreq_remove(struct platform_device *pdev)
+{
+	cpufreq_unregister_driver(&dt_cpufreq_driver);
+	dt_cpufreq_release();
+	return 0;
+}
+
+static struct platform_driver dt_cpufreq_platdrv = {
+	.driver = {
+		.name	= "cpufreq-dt",
+	},
+	.probe		= dt_cpufreq_probe,
+	.remove		= dt_cpufreq_remove,
+};
+module_platform_driver(dt_cpufreq_platdrv);
+
+MODULE_ALIAS("platform:cpufreq-dt");
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
+MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
+MODULE_DESCRIPTION("Generic cpufreq driver");
+MODULE_LICENSE("GPL");