[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)
{
	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
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	{
1a0419b0	50	u64 rate = policy->freq_table[index].frequency * 1000;
343a8d17	51	struct scpi_data *priv = policy->driver_data;
343a8d17 SH	52	int ret;
	53
	54	ret = clk_set_rate(priv->clk, rate);
343a8d17	55
9326fdf3 DE	56	if (ret)
	57	return ret;
	58
	59	if (clk_get_rate(priv->clk) != rate)
	60	return -EIO;
	61
9326fdf3	62	return 0;
343a8d17 SH	63	}
	64
	65	static int
	66	scpi_get_sharing_cpus(struct device cpu_dev, struct cpumask cpumask)
8def3103	67	{
343a8d17 SH	68	int cpu, domain, tdomain;
	69	struct device *tcpu_dev;
	70
	71	domain = scpi_ops->device_domain_id(cpu_dev);
	72	if (domain < 0)
	73	return domain;
	74
	75	for_each_possible_cpu(cpu) {
	76	if (cpu == cpu_dev->id)
	77	continue;
	78
	79	tcpu_dev = get_cpu_device(cpu);
	80	if (!tcpu_dev)
	81	continue;
	82
	83	tdomain = scpi_ops->device_domain_id(tcpu_dev);
	84	if (tdomain == domain)
	85	cpumask_set_cpu(cpu, cpumask);
	86	}
	87
	88	return 0;
d9975b0b SH	89	}
d9975b0b SH	90
343a8d17	91	static int scpi_cpufreq_init(struct cpufreq_policy *policy)
d9975b0b	92	{
c0f2e219	93	int ret;
343a8d17 SH	94	unsigned int latency;
	95	struct device *cpu_dev;
	96	struct scpi_data *priv;
	97	struct cpufreq_frequency_table *freq_table;
	98
	99	cpu_dev = get_cpu_device(policy->cpu);
	100	if (!cpu_dev) {
	101	pr_err("failed to get cpu%d device\n", policy->cpu);
	102	return -ENODEV;
	103	}
8def3103	104
c0f2e219 SH	105	ret = scpi_ops->add_opps_to_device(cpu_dev);
	106	if (ret) {
	107	dev_warn(cpu_dev, "failed to add opps to the device\n");
	108	return ret;
8def3103	109	}
8def3103	110
343a8d17 SH	111	ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
	112	if (ret) {
	113	dev_warn(cpu_dev, "failed to get sharing cpumask\n");
	114	return ret;
	115	}
	116
	117	ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
	118	if (ret) {
d9975b0b SH	119	dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
d9975b0b SH	120	__func__, ret);
343a8d17 SH	121	return ret;
	122	}
	123
	124	ret = dev_pm_opp_get_opp_count(cpu_dev);
	125	if (ret <= 0) {
	126	dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
	127	ret = -EPROBE_DEFER;
	128	goto out_free_opp;
	129	}
	130
	131	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	132	if (!priv) {
	133	ret = -ENOMEM;
	134	goto out_free_opp;
	135	}
	136
	137	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	138	if (ret) {
	139	dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
	140	goto out_free_priv;
	141	}
	142
	143	priv->cpu_dev = cpu_dev;
	144	priv->clk = clk_get(cpu_dev, NULL);
	145	if (IS_ERR(priv->clk)) {
	146	dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
	147	__func__, cpu_dev->id);
0725390d	148	ret = PTR_ERR(priv->clk);
343a8d17 SH	149	goto out_free_cpufreq_table;
	150	}
	151
	152	policy->driver_data = priv;
472ada60	153	policy->freq_table = freq_table;
343a8d17 SH	154
	155	/* scpi allows DVFS request for any domain from any CPU */
	156	policy->dvfs_possible_from_any_cpu = true;
	157
	158	latency = scpi_ops->get_transition_latency(cpu_dev);
	159	if (!latency)
	160	latency = CPUFREQ_ETERNAL;
	161
	162	policy->cpuinfo.transition_latency = latency;
	163
	164	policy->fast_switch_possible = false;
6915d7ad	165
343a8d17 SH	166	return 0;
343a8d17 SH	167
343a8d17 SH	168	out_free_cpufreq_table:
	169	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
	170	out_free_priv:
	171	kfree(priv);
	172	out_free_opp:
1690d8bb	173	dev_pm_opp_remove_all_dynamic(cpu_dev);
343a8d17	174
d9975b0b	175	return ret;
8def3103 SH	176	}
8def3103 SH	177
343a8d17 SH	178	static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
	179	{
	180	struct scpi_data *priv = policy->driver_data;
	181
343a8d17 SH	182	clk_put(priv->clk);
343a8d17 SH	183	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
1690d8bb	184	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
31d4c528	185	kfree(priv);
343a8d17 SH	186
	187	return 0;
	188	}
	189
343a8d17 SH	190	static struct cpufreq_driver scpi_cpufreq_driver = {
343a8d17 SH	191	.name = "scpi-cpufreq",
5ae4a4b4	192	.flags = CPUFREQ_HAVE_GOVERNOR_PER_POLICY \|
cb772b8c AK	193	CPUFREQ_NEED_INITIAL_FREQ_CHECK \|
cb772b8c AK	194	CPUFREQ_IS_COOLING_DEV,
343a8d17 SH	195	.verify = cpufreq_generic_frequency_table_verify,
	196	.attr = cpufreq_generic_attr,
	197	.get = scpi_cpufreq_get_rate,
	198	.init = scpi_cpufreq_init,
	199	.exit = scpi_cpufreq_exit,
343a8d17	200	.target_index = scpi_cpufreq_set_target,
4d584efa	201	.register_em = cpufreq_register_em_with_opp,
8def3103 SH	202	};
	203
	204	static int scpi_cpufreq_probe(struct platform_device *pdev)
	205	{
343a8d17 SH	206	int ret;
343a8d17 SH	207
8def3103 SH	208	scpi_ops = get_scpi_ops();
	209	if (!scpi_ops)
	210	return -EIO;
	211
343a8d17 SH	212	ret = cpufreq_register_driver(&scpi_cpufreq_driver);
	213	if (ret)
	214	dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
	215	__func__, ret);
	216	return ret;
8def3103 SH	217	}
	218
	219	static int scpi_cpufreq_remove(struct platform_device *pdev)
	220	{
343a8d17	221	cpufreq_unregister_driver(&scpi_cpufreq_driver);
8def3103 SH	222	scpi_ops = NULL;
	223	return 0;
	224	}
	225
	226	static struct platform_driver scpi_cpufreq_platdrv = {
	227	.driver = {
	228	.name = "scpi-cpufreq",
8def3103 SH	229	},
	230	.probe = scpi_cpufreq_probe,
	231	.remove = scpi_cpufreq_remove,
	232	};
	233	module_platform_driver(scpi_cpufreq_platdrv);
	234
c0382d04	235	MODULE_ALIAS("platform:scpi-cpufreq");
8def3103 SH	236	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	237	MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
	238	MODULE_LICENSE("GPL v2");