[linux-block.git] / drivers / cpufreq / scpi-cpufreq.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * System Control and Power Interface (SCPI) based CPUFreq Interface driver
 *
 * Copyright (C) 2015 ARM Ltd.
 * Sudeep Holla <sudeep.holla@arm.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/pm_opp.h>
#include <linux/scpi_protocol.h>
#include <linux/slab.h>
#include <linux/types.h>

struct scpi_data {
	struct clk *clk;
	struct device *cpu_dev;
};

static struct scpi_ops *scpi_ops;

static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
{
	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
	struct scpi_data *priv = policy->driver_data;
	unsigned long rate = clk_get_rate(priv->clk);

	return rate / 1000;
}

static int
scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
{
	u64 rate = policy->freq_table[index].frequency * 1000;
	struct scpi_data *priv = policy->driver_data;
	int ret;

	ret = clk_set_rate(priv->clk, rate);

	if (ret)
		return ret;

	if (clk_get_rate(priv->clk) != rate)
		return -EIO;

	return 0;
}

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

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

	return 0;
}

static int scpi_cpufreq_init(struct cpufreq_policy *policy)
{
	int ret;
	unsigned int latency;
	struct device *cpu_dev;
	struct scpi_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;
	}

	ret = scpi_ops->add_opps_to_device(cpu_dev);
	if (ret) {
		dev_warn(cpu_dev, "failed to add opps to the device\n");
		return ret;
	}

	ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
	if (ret) {
		dev_warn(cpu_dev, "failed to get sharing cpumask\n");
		return ret;
	}

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

	ret = dev_pm_opp_get_opp_count(cpu_dev);
	if (ret <= 0) {
		dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
		ret = -EPROBE_DEFER;
		goto out_free_opp;
	}

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv) {
		ret = -ENOMEM;
		goto out_free_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_priv;
	}

	priv->cpu_dev = cpu_dev;
	priv->clk = clk_get(cpu_dev, NULL);
	if (IS_ERR(priv->clk)) {
		dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
			__func__, cpu_dev->id);
		ret = PTR_ERR(priv->clk);
		goto out_free_cpufreq_table;
	}

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

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

	latency = scpi_ops->get_transition_latency(cpu_dev);
	if (!latency)
		latency = CPUFREQ_ETERNAL;

	policy->cpuinfo.transition_latency = latency;

	policy->fast_switch_possible = false;

	return 0;

out_free_cpufreq_table:
	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
out_free_priv:
	kfree(priv);
out_free_opp:
	dev_pm_opp_remove_all_dynamic(cpu_dev);

	return ret;
}

static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
{
	struct scpi_data *priv = policy->driver_data;

	clk_put(priv->clk);
	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
	kfree(priv);

	return 0;
}

static struct cpufreq_driver scpi_cpufreq_driver = {
	.name	= "scpi-cpufreq",
	.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,
	.get	= scpi_cpufreq_get_rate,
	.init	= scpi_cpufreq_init,
	.exit	= scpi_cpufreq_exit,
	.target_index	= scpi_cpufreq_set_target,
	.register_em	= cpufreq_register_em_with_opp,
};

static int scpi_cpufreq_probe(struct platform_device *pdev)
{
	int ret;

	scpi_ops = get_scpi_ops();
	if (!scpi_ops)
		return -EIO;

	ret = cpufreq_register_driver(&scpi_cpufreq_driver);
	if (ret)
		dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
			__func__, ret);
	return ret;
}

static int scpi_cpufreq_remove(struct platform_device *pdev)
{
	cpufreq_unregister_driver(&scpi_cpufreq_driver);
	scpi_ops = NULL;
	return 0;
}

static struct platform_driver scpi_cpufreq_platdrv = {
	.driver = {
		.name	= "scpi-cpufreq",
	},
	.probe		= scpi_cpufreq_probe,
	.remove		= scpi_cpufreq_remove,
};
module_platform_driver(scpi_cpufreq_platdrv);

MODULE_ALIAS("platform:scpi-cpufreq");
MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
5a729246	1	// SPDX-License-Identifier: GPL-2.0-only
8def3103 SH	2	/*
	3	* System Control and Power Interface (SCPI) based CPUFreq Interface driver
	4	*
8def3103 SH	5	* Copyright (C) 2015 ARM Ltd.
8def3103 SH	6	* Sudeep Holla <sudeep.holla@arm.com>
8def3103 SH	7	*/
	8
	9	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	10
343a8d17	11	#include <linux/clk.h>
d9975b0b	12	#include <linux/cpu.h>
8def3103	13	#include <linux/cpufreq.h>
343a8d17	14	#include <linux/cpumask.h>
343a8d17	15	#include <linux/export.h>
8def3103	16	#include <linux/module.h>
343a8d17	17	#include <linux/of_platform.h>
8def3103 SH	18	#include <linux/pm_opp.h>
8def3103 SH	19	#include <linux/scpi_protocol.h>
343a8d17	20	#include <linux/slab.h>
8def3103 SH	21	#include <linux/types.h>
8def3103 SH	22
343a8d17 SH	23	struct scpi_data {
	24	struct clk *clk;
	25	struct device *cpu_dev;
343a8d17	26	};
8def3103 SH	27
	28	static struct scpi_ops *scpi_ops;
	29
343a8d17 SH	30	static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
	31	{
	32	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
	33	struct scpi_data *priv = policy->driver_data;
	34	unsigned long rate = clk_get_rate(priv->clk);
	35
	36	return rate / 1000;
	37	}
	38
	39	static int
	40	scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
	41	{
1a0419b0	42	u64 rate = policy->freq_table[index].frequency * 1000;
343a8d17	43	struct scpi_data *priv = policy->driver_data;
343a8d17 SH	44	int ret;
	45
	46	ret = clk_set_rate(priv->clk, rate);
343a8d17	47
9326fdf3 DE	48	if (ret)
	49	return ret;
	50
	51	if (clk_get_rate(priv->clk) != rate)
	52	return -EIO;
	53
9326fdf3	54	return 0;
343a8d17 SH	55	}
	56
	57	static int
	58	scpi_get_sharing_cpus(struct device cpu_dev, struct cpumask cpumask)
8def3103	59	{
343a8d17 SH	60	int cpu, domain, tdomain;
	61	struct device *tcpu_dev;
	62
	63	domain = scpi_ops->device_domain_id(cpu_dev);
	64	if (domain < 0)
	65	return domain;
	66
	67	for_each_possible_cpu(cpu) {
	68	if (cpu == cpu_dev->id)
	69	continue;
	70
	71	tcpu_dev = get_cpu_device(cpu);
	72	if (!tcpu_dev)
	73	continue;
	74
	75	tdomain = scpi_ops->device_domain_id(tcpu_dev);
	76	if (tdomain == domain)
	77	cpumask_set_cpu(cpu, cpumask);
	78	}
	79
	80	return 0;
d9975b0b SH	81	}
d9975b0b SH	82
343a8d17	83	static int scpi_cpufreq_init(struct cpufreq_policy *policy)
d9975b0b	84	{
c0f2e219	85	int ret;
343a8d17 SH	86	unsigned int latency;
	87	struct device *cpu_dev;
	88	struct scpi_data *priv;
	89	struct cpufreq_frequency_table *freq_table;
	90
	91	cpu_dev = get_cpu_device(policy->cpu);
	92	if (!cpu_dev) {
	93	pr_err("failed to get cpu%d device\n", policy->cpu);
	94	return -ENODEV;
	95	}
8def3103	96
c0f2e219 SH	97	ret = scpi_ops->add_opps_to_device(cpu_dev);
	98	if (ret) {
	99	dev_warn(cpu_dev, "failed to add opps to the device\n");
	100	return ret;
8def3103	101	}
8def3103	102
343a8d17 SH	103	ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
	104	if (ret) {
	105	dev_warn(cpu_dev, "failed to get sharing cpumask\n");
	106	return ret;
	107	}
	108
	109	ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
	110	if (ret) {
d9975b0b SH	111	dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
d9975b0b SH	112	__func__, ret);
343a8d17 SH	113	return ret;
	114	}
	115
	116	ret = dev_pm_opp_get_opp_count(cpu_dev);
	117	if (ret <= 0) {
	118	dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
	119	ret = -EPROBE_DEFER;
	120	goto out_free_opp;
	121	}
	122
	123	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	124	if (!priv) {
	125	ret = -ENOMEM;
	126	goto out_free_opp;
	127	}
	128
	129	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	130	if (ret) {
	131	dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
	132	goto out_free_priv;
	133	}
	134
	135	priv->cpu_dev = cpu_dev;
	136	priv->clk = clk_get(cpu_dev, NULL);
	137	if (IS_ERR(priv->clk)) {
	138	dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
	139	__func__, cpu_dev->id);
0725390d	140	ret = PTR_ERR(priv->clk);
343a8d17 SH	141	goto out_free_cpufreq_table;
	142	}
	143
	144	policy->driver_data = priv;
472ada60	145	policy->freq_table = freq_table;
343a8d17 SH	146
	147	/* scpi allows DVFS request for any domain from any CPU */
	148	policy->dvfs_possible_from_any_cpu = true;
	149
	150	latency = scpi_ops->get_transition_latency(cpu_dev);
	151	if (!latency)
	152	latency = CPUFREQ_ETERNAL;
	153
	154	policy->cpuinfo.transition_latency = latency;
	155
	156	policy->fast_switch_possible = false;
6915d7ad	157
343a8d17 SH	158	return 0;
343a8d17 SH	159
343a8d17 SH	160	out_free_cpufreq_table:
	161	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
	162	out_free_priv:
	163	kfree(priv);
	164	out_free_opp:
1690d8bb	165	dev_pm_opp_remove_all_dynamic(cpu_dev);
343a8d17	166
d9975b0b	167	return ret;
8def3103 SH	168	}
8def3103 SH	169
343a8d17 SH	170	static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
	171	{
	172	struct scpi_data *priv = policy->driver_data;
	173
343a8d17 SH	174	clk_put(priv->clk);
343a8d17 SH	175	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
1690d8bb	176	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
31d4c528	177	kfree(priv);
343a8d17 SH	178
	179	return 0;
	180	}
	181
343a8d17 SH	182	static struct cpufreq_driver scpi_cpufreq_driver = {
343a8d17 SH	183	.name = "scpi-cpufreq",
5ae4a4b4	184	.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY \|
cb772b8c AK	185	CPUFREQ_NEED_INITIAL_FREQ_CHECK \|
cb772b8c AK	186	CPUFREQ_IS_COOLING_DEV,
343a8d17 SH	187	.verify = cpufreq_generic_frequency_table_verify,
	188	.attr = cpufreq_generic_attr,
	189	.get = scpi_cpufreq_get_rate,
	190	.init = scpi_cpufreq_init,
	191	.exit = scpi_cpufreq_exit,
343a8d17	192	.target_index = scpi_cpufreq_set_target,
4d584efa	193	.register_em = cpufreq_register_em_with_opp,
8def3103 SH	194	};
	195
	196	static int scpi_cpufreq_probe(struct platform_device *pdev)
	197	{
343a8d17 SH	198	int ret;
343a8d17 SH	199
8def3103 SH	200	scpi_ops = get_scpi_ops();
	201	if (!scpi_ops)
	202	return -EIO;
	203
343a8d17 SH	204	ret = cpufreq_register_driver(&scpi_cpufreq_driver);
	205	if (ret)
	206	dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
	207	__func__, ret);
	208	return ret;
8def3103 SH	209	}
	210
	211	static int scpi_cpufreq_remove(struct platform_device *pdev)
	212	{
343a8d17	213	cpufreq_unregister_driver(&scpi_cpufreq_driver);
8def3103 SH	214	scpi_ops = NULL;
	215	return 0;
	216	}
	217
	218	static struct platform_driver scpi_cpufreq_platdrv = {
	219	.driver = {
	220	.name = "scpi-cpufreq",
8def3103 SH	221	},
	222	.probe = scpi_cpufreq_probe,
	223	.remove = scpi_cpufreq_remove,
	224	};
	225	module_platform_driver(scpi_cpufreq_platdrv);
	226
c0382d04	227	MODULE_ALIAS("platform:scpi-cpufreq");
8def3103 SH	228	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	229	MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
	230	MODULE_LICENSE("GPL v2");