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

/*
 * System Control and Power Interface (SCPI) based CPUFreq Interface driver
 *
 * Copyright (C) 2015 ARM Ltd.
 * Sudeep Holla <sudeep.holla@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

#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)
{
	unsigned long freq = policy->freq_table[index].frequency;
	struct scpi_data *priv = policy->driver_data;
	u64 rate = freq * 1000;
	int ret;

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

	if (ret)
		return ret;

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

	arch_set_freq_scale(policy->related_cpus, freq,
			    policy->cpuinfo.max_freq);

	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;

	dev_pm_opp_of_register_em(cpu_dev, policy->cpus);

	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_STICKY | 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,
};

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_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
8def3103 SH	1	/*
	2	* System Control and Power Interface (SCPI) based CPUFreq Interface driver
	3	*
8def3103 SH	4	* Copyright (C) 2015 ARM Ltd.
	5	* Sudeep Holla <sudeep.holla@arm.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	12	* kind, whether express or implied; without even the implied warranty
	13	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*/
	16
	17	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	18
343a8d17	19	#include <linux/clk.h>
d9975b0b	20	#include <linux/cpu.h>
8def3103	21	#include <linux/cpufreq.h>
343a8d17	22	#include <linux/cpumask.h>
343a8d17	23	#include <linux/export.h>
8def3103	24	#include <linux/module.h>
343a8d17	25	#include <linux/of_platform.h>
8def3103 SH	26	#include <linux/pm_opp.h>
8def3103 SH	27	#include <linux/scpi_protocol.h>
343a8d17	28	#include <linux/slab.h>
8def3103 SH	29	#include <linux/types.h>
8def3103 SH	30
343a8d17 SH	31	struct scpi_data {
	32	struct clk *clk;
	33	struct device *cpu_dev;
343a8d17	34	};
8def3103 SH	35
	36	static struct scpi_ops *scpi_ops;
	37
343a8d17 SH	38	static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
	39	{
	40	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
	41	struct scpi_data *priv = policy->driver_data;
	42	unsigned long rate = clk_get_rate(priv->clk);
	43
	44	return rate / 1000;
	45	}
	46
	47	static int
	48	scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
	49	{
9326fdf3	50	unsigned long freq = policy->freq_table[index].frequency;
343a8d17	51	struct scpi_data *priv = policy->driver_data;
9326fdf3	52	u64 rate = freq * 1000;
343a8d17 SH	53	int ret;
	54
	55	ret = clk_set_rate(priv->clk, rate);
343a8d17	56
9326fdf3 DE	57	if (ret)
	58	return ret;
	59
	60	if (clk_get_rate(priv->clk) != rate)
	61	return -EIO;
	62
	63	arch_set_freq_scale(policy->related_cpus, freq,
	64	policy->cpuinfo.max_freq);
	65
	66	return 0;
343a8d17 SH	67	}
	68
	69	static int
	70	scpi_get_sharing_cpus(struct device cpu_dev, struct cpumask cpumask)
8def3103	71	{
343a8d17 SH	72	int cpu, domain, tdomain;
	73	struct device *tcpu_dev;
	74
	75	domain = scpi_ops->device_domain_id(cpu_dev);
	76	if (domain < 0)
	77	return domain;
	78
	79	for_each_possible_cpu(cpu) {
	80	if (cpu == cpu_dev->id)
	81	continue;
	82
	83	tcpu_dev = get_cpu_device(cpu);
	84	if (!tcpu_dev)
	85	continue;
	86
	87	tdomain = scpi_ops->device_domain_id(tcpu_dev);
	88	if (tdomain == domain)
	89	cpumask_set_cpu(cpu, cpumask);
	90	}
	91
	92	return 0;
d9975b0b SH	93	}
d9975b0b SH	94
343a8d17	95	static int scpi_cpufreq_init(struct cpufreq_policy *policy)
d9975b0b	96	{
c0f2e219	97	int ret;
343a8d17 SH	98	unsigned int latency;
	99	struct device *cpu_dev;
	100	struct scpi_data *priv;
	101	struct cpufreq_frequency_table *freq_table;
	102
	103	cpu_dev = get_cpu_device(policy->cpu);
	104	if (!cpu_dev) {
	105	pr_err("failed to get cpu%d device\n", policy->cpu);
	106	return -ENODEV;
	107	}
8def3103	108
c0f2e219 SH	109	ret = scpi_ops->add_opps_to_device(cpu_dev);
	110	if (ret) {
	111	dev_warn(cpu_dev, "failed to add opps to the device\n");
	112	return ret;
8def3103	113	}
8def3103	114
343a8d17 SH	115	ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
	116	if (ret) {
	117	dev_warn(cpu_dev, "failed to get sharing cpumask\n");
	118	return ret;
	119	}
	120
	121	ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
	122	if (ret) {
d9975b0b SH	123	dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
d9975b0b SH	124	__func__, ret);
343a8d17 SH	125	return ret;
	126	}
	127
	128	ret = dev_pm_opp_get_opp_count(cpu_dev);
	129	if (ret <= 0) {
	130	dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
	131	ret = -EPROBE_DEFER;
	132	goto out_free_opp;
	133	}
	134
	135	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	136	if (!priv) {
	137	ret = -ENOMEM;
	138	goto out_free_opp;
	139	}
	140
	141	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	142	if (ret) {
	143	dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
	144	goto out_free_priv;
	145	}
	146
	147	priv->cpu_dev = cpu_dev;
	148	priv->clk = clk_get(cpu_dev, NULL);
	149	if (IS_ERR(priv->clk)) {
	150	dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
	151	__func__, cpu_dev->id);
0725390d	152	ret = PTR_ERR(priv->clk);
343a8d17 SH	153	goto out_free_cpufreq_table;
	154	}
	155
	156	policy->driver_data = priv;
472ada60	157	policy->freq_table = freq_table;
343a8d17 SH	158
	159	/* scpi allows DVFS request for any domain from any CPU */
	160	policy->dvfs_possible_from_any_cpu = true;
	161
	162	latency = scpi_ops->get_transition_latency(cpu_dev);
	163	if (!latency)
	164	latency = CPUFREQ_ETERNAL;
	165
	166	policy->cpuinfo.transition_latency = latency;
	167
	168	policy->fast_switch_possible = false;
6915d7ad	169
0e0ffa85	170	dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
6915d7ad	171
343a8d17 SH	172	return 0;
343a8d17 SH	173
343a8d17 SH	174	out_free_cpufreq_table:
	175	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
	176	out_free_priv:
	177	kfree(priv);
	178	out_free_opp:
1690d8bb	179	dev_pm_opp_remove_all_dynamic(cpu_dev);
343a8d17	180
d9975b0b	181	return ret;
8def3103 SH	182	}
8def3103 SH	183
343a8d17 SH	184	static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
	185	{
	186	struct scpi_data *priv = policy->driver_data;
	187
343a8d17 SH	188	clk_put(priv->clk);
343a8d17 SH	189	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
1690d8bb	190	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
31d4c528	191	kfree(priv);
343a8d17 SH	192
	193	return 0;
	194	}
	195
343a8d17 SH	196	static struct cpufreq_driver scpi_cpufreq_driver = {
	197	.name = "scpi-cpufreq",
	198	.flags = CPUFREQ_STICKY \| CPUFREQ_HAVE_GOVERNOR_PER_POLICY \|
cb772b8c AK	199	CPUFREQ_NEED_INITIAL_FREQ_CHECK \|
cb772b8c AK	200	CPUFREQ_IS_COOLING_DEV,
343a8d17 SH	201	.verify = cpufreq_generic_frequency_table_verify,
	202	.attr = cpufreq_generic_attr,
	203	.get = scpi_cpufreq_get_rate,
	204	.init = scpi_cpufreq_init,
	205	.exit = scpi_cpufreq_exit,
343a8d17	206	.target_index = scpi_cpufreq_set_target,
8def3103 SH	207	};
	208
	209	static int scpi_cpufreq_probe(struct platform_device *pdev)
	210	{
343a8d17 SH	211	int ret;
343a8d17 SH	212
8def3103 SH	213	scpi_ops = get_scpi_ops();
	214	if (!scpi_ops)
	215	return -EIO;
	216
343a8d17 SH	217	ret = cpufreq_register_driver(&scpi_cpufreq_driver);
	218	if (ret)
	219	dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
	220	__func__, ret);
	221	return ret;
8def3103 SH	222	}
	223
	224	static int scpi_cpufreq_remove(struct platform_device *pdev)
	225	{
343a8d17	226	cpufreq_unregister_driver(&scpi_cpufreq_driver);
8def3103 SH	227	scpi_ops = NULL;
	228	return 0;
	229	}
	230
	231	static struct platform_driver scpi_cpufreq_platdrv = {
	232	.driver = {
	233	.name = "scpi-cpufreq",
8def3103 SH	234	},
	235	.probe = scpi_cpufreq_probe,
	236	.remove = scpi_cpufreq_remove,
	237	};
	238	module_platform_driver(scpi_cpufreq_platdrv);
	239
	240	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	241	MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
	242	MODULE_LICENSE("GPL v2");