drivers/cpufreq/scmi-cpufreq.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * System Control and Power Interface (SCMI) based CPUFreq Interface driver
  *
  * Copyright (C) 2018-2021 ARM Ltd.
  * Sudeep Holla <sudeep.holla@arm.com>
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/clk-provider.h>
 #include <linux/cpu.h>
 #include <linux/cpufreq.h>
 #include <linux/cpumask.h>
 #include <linux/energy_model.h>
 #include <linux/export.h>
 #include <linux/module.h>
 #include <linux/pm_opp.h>
 #include <linux/slab.h>
 #include <linux/scmi_protocol.h>
 #include <linux/types.h>
 #include <linux/units.h>

 struct scmi_data {
 	int domain_id;
 	int nr_opp;
 	struct device *cpu_dev;
 	cpumask_var_t opp_shared_cpus;
 };

 static struct scmi_protocol_handle *ph;
 static const struct scmi_perf_proto_ops *perf_ops;

 static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
 {
 	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
 	struct scmi_data *priv = policy->driver_data;
 	unsigned long rate;
 	int ret;

 	ret = perf_ops->freq_get(ph, priv->domain_id, &rate, false);
 	if (ret)
 		return 0;
 	return rate / 1000;
 }

 /*
  * perf_ops->freq_set is not a synchronous, the actual OPP change will
  * happen asynchronously and can get notified if the events are
  * subscribed for by the SCMI firmware
  */
 static int
 scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
 {
 	struct scmi_data *priv = policy->driver_data;
 	u64 freq = policy->freq_table[index].frequency;

 	return perf_ops->freq_set(ph, priv->domain_id, freq * 1000, false);
 }

 static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
 					     unsigned int target_freq)
 {
 	struct scmi_data *priv = policy->driver_data;

 	if (!perf_ops->freq_set(ph, priv->domain_id,
 				target_freq * 1000, true))
 		return target_freq;

 	return 0;
 }

 static int
 scmi_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
 {
 	int cpu, domain, tdomain;
 	struct device *tcpu_dev;

 	domain = perf_ops->device_domain_id(cpu_dev);
 	if (domain < 0)
 		return domain;

 	for_each_possible_cpu(cpu) {
 		if (cpu == cpu_dev->id)
 			continue;

 		tcpu_dev = get_cpu_device(cpu);
 		if (!tcpu_dev)
 			continue;

 		tdomain = perf_ops->device_domain_id(tcpu_dev);
 		if (tdomain == domain)
 			cpumask_set_cpu(cpu, cpumask);
 	}

 	return 0;
 }

 static int __maybe_unused
 scmi_get_cpu_power(struct device *cpu_dev, unsigned long *power,
 		   unsigned long *KHz)
 {
 	enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
 	unsigned long Hz;
 	int ret, domain;

 	domain = perf_ops->device_domain_id(cpu_dev);
 	if (domain < 0)
 		return domain;

 	/* Get the power cost of the performance domain. */
 	Hz = *KHz * 1000;
 	ret = perf_ops->est_power_get(ph, domain, &Hz, power);
 	if (ret)
 		return ret;

 	/* Convert the power to uW if it is mW (ignore bogoW) */
 	if (power_scale == SCMI_POWER_MILLIWATTS)
 		*power *= MICROWATT_PER_MILLIWATT;

 	/* The EM framework specifies the frequency in KHz. */
 	*KHz = Hz / 1000;

 	return 0;
 }

 static int scmi_cpufreq_init(struct cpufreq_policy *policy)
 {
 	int ret, nr_opp;
 	unsigned int latency;
 	struct device *cpu_dev;
 	struct scmi_data *priv;
 	struct cpufreq_frequency_table *freq_table;

 	cpu_dev = get_cpu_device(policy->cpu);
 	if (!cpu_dev) {
 		pr_err("failed to get cpu%d device\n", policy->cpu);
 		return -ENODEV;
 	}

 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	if (!zalloc_cpumask_var(&priv->opp_shared_cpus, GFP_KERNEL)) {
 		ret = -ENOMEM;
 		goto out_free_priv;
 	}

 	/* Obtain CPUs that share SCMI performance controls */
 	ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
 	if (ret) {
 		dev_warn(cpu_dev, "failed to get sharing cpumask\n");
 		goto out_free_cpumask;
 	}

 	/*
 	 * Obtain CPUs that share performance levels.
 	 * The OPP 'sharing cpus' info may come from DT through an empty opp
 	 * table and opp-shared.
 	 */
 	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
 	if (ret || cpumask_empty(priv->opp_shared_cpus)) {
 		/*
 		 * Either opp-table is not set or no opp-shared was found.
 		 * Use the CPU mask from SCMI to designate CPUs sharing an OPP
 		 * table.
 		 */
 		cpumask_copy(priv->opp_shared_cpus, policy->cpus);
 	}

 	 /*
 	  * A previous CPU may have marked OPPs as shared for a few CPUs, based on
 	  * what OPP core provided. If the current CPU is part of those few, then
 	  * there is no need to add OPPs again.
 	  */
 	nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
 	if (nr_opp <= 0) {
 		ret = perf_ops->device_opps_add(ph, cpu_dev);
 		if (ret) {
 			dev_warn(cpu_dev, "failed to add opps to the device\n");
 			goto out_free_cpumask;
 		}

 		nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
 		if (nr_opp <= 0) {
 			dev_err(cpu_dev, "%s: No OPPs for this device: %d\n",
 				__func__, nr_opp);

 			ret = -ENODEV;
 			goto out_free_opp;
 		}

 		ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
 		if (ret) {
 			dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
 				__func__, ret);

 			goto out_free_opp;
 		}

 		priv->nr_opp = nr_opp;
 	}

 	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
 	if (ret) {
 		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
 		goto out_free_opp;
 	}

 	priv->cpu_dev = cpu_dev;
 	priv->domain_id = perf_ops->device_domain_id(cpu_dev);

 	policy->driver_data = priv;
 	policy->freq_table = freq_table;

 	/* SCMI allows DVFS request for any domain from any CPU */
 	policy->dvfs_possible_from_any_cpu = true;

 	latency = perf_ops->transition_latency_get(ph, cpu_dev);
 	if (!latency)
 		latency = CPUFREQ_ETERNAL;

 	policy->cpuinfo.transition_latency = latency;

 	policy->fast_switch_possible =
 		perf_ops->fast_switch_possible(ph, cpu_dev);

 	return 0;

 out_free_opp:
 	dev_pm_opp_remove_all_dynamic(cpu_dev);

 out_free_cpumask:
 	free_cpumask_var(priv->opp_shared_cpus);

 out_free_priv:
 	kfree(priv);

 	return ret;
 }

 static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
 {
 	struct scmi_data *priv = policy->driver_data;

 	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
 	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
 	free_cpumask_var(priv->opp_shared_cpus);
 	kfree(priv);

 	return 0;
 }

 static void scmi_cpufreq_register_em(struct cpufreq_policy *policy)
 {
 	struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
 	enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
 	struct scmi_data *priv = policy->driver_data;
 	bool em_power_scale = false;

 	/*
 	 * This callback will be called for each policy, but we don't need to
 	 * register with EM every time. Despite not being part of the same
 	 * policy, some CPUs may still share their perf-domains, and a CPU from
 	 * another policy may already have registered with EM on behalf of CPUs
 	 * of this policy.
 	 */
 	if (!priv->nr_opp)
 		return;

 	if (power_scale == SCMI_POWER_MILLIWATTS
 	    || power_scale == SCMI_POWER_MICROWATTS)
 		em_power_scale = true;

 	em_dev_register_perf_domain(get_cpu_device(policy->cpu), priv->nr_opp,
 				    &em_cb, priv->opp_shared_cpus,
 				    em_power_scale);
 }

 static struct cpufreq_driver scmi_cpufreq_driver = {
 	.name	= "scmi",
 	.flags	= CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
 		  CPUFREQ_NEED_INITIAL_FREQ_CHECK |
 		  CPUFREQ_IS_COOLING_DEV,
 	.verify	= cpufreq_generic_frequency_table_verify,
 	.attr	= cpufreq_generic_attr,
 	.target_index	= scmi_cpufreq_set_target,
 	.fast_switch	= scmi_cpufreq_fast_switch,
 	.get	= scmi_cpufreq_get_rate,
 	.init	= scmi_cpufreq_init,
 	.exit	= scmi_cpufreq_exit,
 	.register_em	= scmi_cpufreq_register_em,
 };

 static int scmi_cpufreq_probe(struct scmi_device *sdev)
 {
 	int ret;
 	struct device *dev = &sdev->dev;
 	const struct scmi_handle *handle;

 	handle = sdev->handle;

 	if (!handle)
 		return -ENODEV;

 	perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph);
 	if (IS_ERR(perf_ops))
 		return PTR_ERR(perf_ops);

 #ifdef CONFIG_COMMON_CLK
 	/* dummy clock provider as needed by OPP if clocks property is used */
 	if (of_property_present(dev->of_node, "#clock-cells"))
 		devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL);
 #endif

 	ret = cpufreq_register_driver(&scmi_cpufreq_driver);
 	if (ret) {
 		dev_err(dev, "%s: registering cpufreq failed, err: %d\n",
 			__func__, ret);
 	}

 	return ret;
 }

 static void scmi_cpufreq_remove(struct scmi_device *sdev)
 {
 	cpufreq_unregister_driver(&scmi_cpufreq_driver);
 }

 static const struct scmi_device_id scmi_id_table[] = {
 	{ SCMI_PROTOCOL_PERF, "cpufreq" },
 	{ },
 };
 MODULE_DEVICE_TABLE(scmi, scmi_id_table);

 static struct scmi_driver scmi_cpufreq_drv = {
 	.name		= "scmi-cpufreq",
 	.probe		= scmi_cpufreq_probe,
 	.remove		= scmi_cpufreq_remove,
 	.id_table	= scmi_id_table,
 };
 module_scmi_driver(scmi_cpufreq_drv);

 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
 MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* System Control and Power Interface (SCMI) based CPUFreq Interface driver
	*
	* Copyright (C) 2018-2021 ARM Ltd.
	* Sudeep Holla <sudeep.holla@arm.com>
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/clk-provider.h>
	#include <linux/cpu.h>
	#include <linux/cpufreq.h>
	#include <linux/cpumask.h>
	#include <linux/energy_model.h>
	#include <linux/export.h>
	#include <linux/module.h>
	#include <linux/pm_opp.h>
	#include <linux/slab.h>
	#include <linux/scmi_protocol.h>
	#include <linux/types.h>
	#include <linux/units.h>

	struct scmi_data {
	int domain_id;
	int nr_opp;
	struct device *cpu_dev;
	cpumask_var_t opp_shared_cpus;
	};

	static struct scmi_protocol_handle *ph;
	static const struct scmi_perf_proto_ops *perf_ops;

	static unsigned int scmi_cpufreq_get_rate(unsigned int cpu)
	{
	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
	struct scmi_data *priv = policy->driver_data;
	unsigned long rate;
	int ret;

	ret = perf_ops->freq_get(ph, priv->domain_id, &rate, false);
	if (ret)
	return 0;
	return rate / 1000;
	}

	/*
	* perf_ops->freq_set is not a synchronous, the actual OPP change will
	* happen asynchronously and can get notified if the events are
	* subscribed for by the SCMI firmware
	*/
	static int
	scmi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
	{
	struct scmi_data *priv = policy->driver_data;
	u64 freq = policy->freq_table[index].frequency;

	return perf_ops->freq_set(ph, priv->domain_id, freq * 1000, false);
	}

	static unsigned int scmi_cpufreq_fast_switch(struct cpufreq_policy *policy,
	unsigned int target_freq)
	{
	struct scmi_data *priv = policy->driver_data;

	if (!perf_ops->freq_set(ph, priv->domain_id,
	target_freq * 1000, true))
	return target_freq;

	return 0;
	}

	static int
	scmi_get_sharing_cpus(struct device cpu_dev, struct cpumask cpumask)
	{
	int cpu, domain, tdomain;
	struct device *tcpu_dev;

	domain = perf_ops->device_domain_id(cpu_dev);
	if (domain < 0)
	return domain;

	for_each_possible_cpu(cpu) {
	if (cpu == cpu_dev->id)
	continue;

	tcpu_dev = get_cpu_device(cpu);
	if (!tcpu_dev)
	continue;

	tdomain = perf_ops->device_domain_id(tcpu_dev);
	if (tdomain == domain)
	cpumask_set_cpu(cpu, cpumask);
	}

	return 0;
	}

	static int __maybe_unused
	scmi_get_cpu_power(struct device cpu_dev, unsigned long power,
	unsigned long *KHz)
	{
	enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
	unsigned long Hz;
	int ret, domain;

	domain = perf_ops->device_domain_id(cpu_dev);
	if (domain < 0)
	return domain;

	/* Get the power cost of the performance domain. */
	Hz = KHz 1000;
	ret = perf_ops->est_power_get(ph, domain, &Hz, power);
	if (ret)
	return ret;

	/* Convert the power to uW if it is mW (ignore bogoW) */
	if (power_scale == SCMI_POWER_MILLIWATTS)
	power = MICROWATT_PER_MILLIWATT;

	/* The EM framework specifies the frequency in KHz. */
	*KHz = Hz / 1000;

	return 0;
	}

	static int scmi_cpufreq_init(struct cpufreq_policy *policy)
	{
	int ret, nr_opp;
	unsigned int latency;
	struct device *cpu_dev;
	struct scmi_data *priv;
	struct cpufreq_frequency_table *freq_table;

	cpu_dev = get_cpu_device(policy->cpu);
	if (!cpu_dev) {
	pr_err("failed to get cpu%d device\n", policy->cpu);
	return -ENODEV;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	if (!zalloc_cpumask_var(&priv->opp_shared_cpus, GFP_KERNEL)) {
	ret = -ENOMEM;
	goto out_free_priv;
	}

	/* Obtain CPUs that share SCMI performance controls */
	ret = scmi_get_sharing_cpus(cpu_dev, policy->cpus);
	if (ret) {
	dev_warn(cpu_dev, "failed to get sharing cpumask\n");
	goto out_free_cpumask;
	}

	/*
	* Obtain CPUs that share performance levels.
	* The OPP 'sharing cpus' info may come from DT through an empty opp
	* table and opp-shared.
	*/
	ret = dev_pm_opp_of_get_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
	if (ret \|\| cpumask_empty(priv->opp_shared_cpus)) {
	/*
	* Either opp-table is not set or no opp-shared was found.
	* Use the CPU mask from SCMI to designate CPUs sharing an OPP
	* table.
	*/
	cpumask_copy(priv->opp_shared_cpus, policy->cpus);
	}

	/*
	* A previous CPU may have marked OPPs as shared for a few CPUs, based on
	* what OPP core provided. If the current CPU is part of those few, then
	* there is no need to add OPPs again.
	*/
	nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
	if (nr_opp <= 0) {
	ret = perf_ops->device_opps_add(ph, cpu_dev);
	if (ret) {
	dev_warn(cpu_dev, "failed to add opps to the device\n");
	goto out_free_cpumask;
	}

	nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
	if (nr_opp <= 0) {
	dev_err(cpu_dev, "%s: No OPPs for this device: %d\n",
	__func__, nr_opp);

	ret = -ENODEV;
	goto out_free_opp;
	}

	ret = dev_pm_opp_set_sharing_cpus(cpu_dev, priv->opp_shared_cpus);
	if (ret) {
	dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
	__func__, ret);

	goto out_free_opp;
	}

	priv->nr_opp = nr_opp;
	}

	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	if (ret) {
	dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
	goto out_free_opp;
	}

	priv->cpu_dev = cpu_dev;
	priv->domain_id = perf_ops->device_domain_id(cpu_dev);

	policy->driver_data = priv;
	policy->freq_table = freq_table;

	/* SCMI allows DVFS request for any domain from any CPU */
	policy->dvfs_possible_from_any_cpu = true;

	latency = perf_ops->transition_latency_get(ph, cpu_dev);
	if (!latency)
	latency = CPUFREQ_ETERNAL;

	policy->cpuinfo.transition_latency = latency;

	policy->fast_switch_possible =
	perf_ops->fast_switch_possible(ph, cpu_dev);

	return 0;

	out_free_opp:
	dev_pm_opp_remove_all_dynamic(cpu_dev);

	out_free_cpumask:
	free_cpumask_var(priv->opp_shared_cpus);

	out_free_priv:
	kfree(priv);

	return ret;
	}

	static int scmi_cpufreq_exit(struct cpufreq_policy *policy)
	{
	struct scmi_data *priv = policy->driver_data;

	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
	free_cpumask_var(priv->opp_shared_cpus);
	kfree(priv);

	return 0;
	}

	static void scmi_cpufreq_register_em(struct cpufreq_policy *policy)
	{
	struct em_data_callback em_cb = EM_DATA_CB(scmi_get_cpu_power);
	enum scmi_power_scale power_scale = perf_ops->power_scale_get(ph);
	struct scmi_data *priv = policy->driver_data;
	bool em_power_scale = false;

	/*
	* This callback will be called for each policy, but we don't need to
	* register with EM every time. Despite not being part of the same
	* policy, some CPUs may still share their perf-domains, and a CPU from
	* another policy may already have registered with EM on behalf of CPUs
	* of this policy.
	*/
	if (!priv->nr_opp)
	return;

	if (power_scale == SCMI_POWER_MILLIWATTS
	\|\| power_scale == SCMI_POWER_MICROWATTS)
	em_power_scale = true;

	em_dev_register_perf_domain(get_cpu_device(policy->cpu), priv->nr_opp,
	&em_cb, priv->opp_shared_cpus,
	em_power_scale);
	}

	static struct cpufreq_driver scmi_cpufreq_driver = {
	.name = "scmi",
	.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY \|
	CPUFREQ_NEED_INITIAL_FREQ_CHECK \|
	CPUFREQ_IS_COOLING_DEV,
	.verify = cpufreq_generic_frequency_table_verify,
	.attr = cpufreq_generic_attr,
	.target_index = scmi_cpufreq_set_target,
	.fast_switch = scmi_cpufreq_fast_switch,
	.get = scmi_cpufreq_get_rate,
	.init = scmi_cpufreq_init,
	.exit = scmi_cpufreq_exit,
	.register_em = scmi_cpufreq_register_em,
	};

	static int scmi_cpufreq_probe(struct scmi_device *sdev)
	{
	int ret;
	struct device *dev = &sdev->dev;
	const struct scmi_handle *handle;

	handle = sdev->handle;

	if (!handle)
	return -ENODEV;

	perf_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_PERF, &ph);
	if (IS_ERR(perf_ops))
	return PTR_ERR(perf_ops);

	#ifdef CONFIG_COMMON_CLK
	/* dummy clock provider as needed by OPP if clocks property is used */
	if (of_property_present(dev->of_node, "#clock-cells"))
	devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, NULL);
	#endif

	ret = cpufreq_register_driver(&scmi_cpufreq_driver);
	if (ret) {
	dev_err(dev, "%s: registering cpufreq failed, err: %d\n",
	__func__, ret);
	}

	return ret;
	}

	static void scmi_cpufreq_remove(struct scmi_device *sdev)
	{
	cpufreq_unregister_driver(&scmi_cpufreq_driver);
	}

	static const struct scmi_device_id scmi_id_table[] = {
	{ SCMI_PROTOCOL_PERF, "cpufreq" },
	{ },
	};
	MODULE_DEVICE_TABLE(scmi, scmi_id_table);

	static struct scmi_driver scmi_cpufreq_drv = {
	.name = "scmi-cpufreq",
	.probe = scmi_cpufreq_probe,
	.remove = scmi_cpufreq_remove,
	.id_table = scmi_id_table,
	};
	module_scmi_driver(scmi_cpufreq_drv);

	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	MODULE_DESCRIPTION("ARM SCMI CPUFreq interface driver");
	MODULE_LICENSE("GPL v2");