[linux-2.6-block.git] / drivers / cpufreq / scpi-cpufreq.c

/*
 * System Control and Power Interface (SCPI) based CPUFreq Interface driver
 *
 * It provides necessary ops to arm_big_little cpufreq 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/cpu_cooling.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;
	struct thermal_cooling_device *cdev;
};

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;
	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;

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

	return 0;
}

static void scpi_cpufreq_ready(struct cpufreq_policy *policy)
{
	struct scpi_data *priv = policy->driver_data;

	priv->cdev = of_cpufreq_cooling_register(policy);
}

static struct cpufreq_driver scpi_cpufreq_driver = {
	.name	= "scpi-cpufreq",
	.flags	= CPUFREQ_STICKY | CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
		  CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	.verify	= cpufreq_generic_frequency_table_verify,
	.attr	= cpufreq_generic_attr,
	.get	= scpi_cpufreq_get_rate,
	.init	= scpi_cpufreq_init,
	.exit	= scpi_cpufreq_exit,
	.ready	= scpi_cpufreq_ready,
	.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	*
	4	* It provides necessary ops to arm_big_little cpufreq driver.
	5	*
	6	* Copyright (C) 2015 ARM Ltd.
	7	* Sudeep Holla <sudeep.holla@arm.com>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*
	13	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	14	* kind, whether express or implied; without even the implied warranty
	15	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*/
	18
	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	20
343a8d17	21	#include <linux/clk.h>
d9975b0b	22	#include <linux/cpu.h>
8def3103	23	#include <linux/cpufreq.h>
343a8d17 SH	24	#include <linux/cpumask.h>
	25	#include <linux/cpu_cooling.h>
	26	#include <linux/export.h>
8def3103	27	#include <linux/module.h>
343a8d17	28	#include <linux/of_platform.h>
8def3103 SH	29	#include <linux/pm_opp.h>
8def3103 SH	30	#include <linux/scpi_protocol.h>
343a8d17	31	#include <linux/slab.h>
8def3103 SH	32	#include <linux/types.h>
8def3103 SH	33
343a8d17 SH	34	struct scpi_data {
	35	struct clk *clk;
	36	struct device *cpu_dev;
	37	struct thermal_cooling_device *cdev;
	38	};
8def3103 SH	39
	40	static struct scpi_ops *scpi_ops;
	41
343a8d17 SH	42	static unsigned int scpi_cpufreq_get_rate(unsigned int cpu)
	43	{
	44	struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu);
	45	struct scpi_data *priv = policy->driver_data;
	46	unsigned long rate = clk_get_rate(priv->clk);
	47
	48	return rate / 1000;
	49	}
	50
	51	static int
	52	scpi_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index)
	53	{
9326fdf3	54	unsigned long freq = policy->freq_table[index].frequency;
343a8d17	55	struct scpi_data *priv = policy->driver_data;
9326fdf3	56	u64 rate = freq * 1000;
343a8d17 SH	57	int ret;
	58
	59	ret = clk_set_rate(priv->clk, rate);
343a8d17	60
9326fdf3 DE	61	if (ret)
	62	return ret;
	63
	64	if (clk_get_rate(priv->clk) != rate)
	65	return -EIO;
	66
	67	arch_set_freq_scale(policy->related_cpus, freq,
	68	policy->cpuinfo.max_freq);
	69
	70	return 0;
343a8d17 SH	71	}
	72
	73	static int
	74	scpi_get_sharing_cpus(struct device cpu_dev, struct cpumask cpumask)
8def3103	75	{
343a8d17 SH	76	int cpu, domain, tdomain;
	77	struct device *tcpu_dev;
	78
	79	domain = scpi_ops->device_domain_id(cpu_dev);
	80	if (domain < 0)
	81	return domain;
	82
	83	for_each_possible_cpu(cpu) {
	84	if (cpu == cpu_dev->id)
	85	continue;
	86
	87	tcpu_dev = get_cpu_device(cpu);
	88	if (!tcpu_dev)
	89	continue;
	90
	91	tdomain = scpi_ops->device_domain_id(tcpu_dev);
	92	if (tdomain == domain)
	93	cpumask_set_cpu(cpu, cpumask);
	94	}
	95
	96	return 0;
d9975b0b SH	97	}
d9975b0b SH	98
343a8d17	99	static int scpi_cpufreq_init(struct cpufreq_policy *policy)
d9975b0b	100	{
c0f2e219	101	int ret;
343a8d17 SH	102	unsigned int latency;
	103	struct device *cpu_dev;
	104	struct scpi_data *priv;
	105	struct cpufreq_frequency_table *freq_table;
	106
	107	cpu_dev = get_cpu_device(policy->cpu);
	108	if (!cpu_dev) {
	109	pr_err("failed to get cpu%d device\n", policy->cpu);
	110	return -ENODEV;
	111	}
8def3103	112
c0f2e219 SH	113	ret = scpi_ops->add_opps_to_device(cpu_dev);
	114	if (ret) {
	115	dev_warn(cpu_dev, "failed to add opps to the device\n");
	116	return ret;
8def3103	117	}
8def3103	118
343a8d17 SH	119	ret = scpi_get_sharing_cpus(cpu_dev, policy->cpus);
	120	if (ret) {
	121	dev_warn(cpu_dev, "failed to get sharing cpumask\n");
	122	return ret;
	123	}
	124
	125	ret = dev_pm_opp_set_sharing_cpus(cpu_dev, policy->cpus);
	126	if (ret) {
d9975b0b SH	127	dev_err(cpu_dev, "%s: failed to mark OPPs as shared: %d\n",
d9975b0b SH	128	__func__, ret);
343a8d17 SH	129	return ret;
	130	}
	131
	132	ret = dev_pm_opp_get_opp_count(cpu_dev);
	133	if (ret <= 0) {
	134	dev_dbg(cpu_dev, "OPP table is not ready, deferring probe\n");
	135	ret = -EPROBE_DEFER;
	136	goto out_free_opp;
	137	}
	138
	139	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	140	if (!priv) {
	141	ret = -ENOMEM;
	142	goto out_free_opp;
	143	}
	144
	145	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
	146	if (ret) {
	147	dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
	148	goto out_free_priv;
	149	}
	150
	151	priv->cpu_dev = cpu_dev;
	152	priv->clk = clk_get(cpu_dev, NULL);
	153	if (IS_ERR(priv->clk)) {
	154	dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d\n",
	155	__func__, cpu_dev->id);
0725390d	156	ret = PTR_ERR(priv->clk);
343a8d17 SH	157	goto out_free_cpufreq_table;
	158	}
	159
	160	policy->driver_data = priv;
472ada60	161	policy->freq_table = freq_table;
343a8d17 SH	162
	163	/* scpi allows DVFS request for any domain from any CPU */
	164	policy->dvfs_possible_from_any_cpu = true;
	165
	166	latency = scpi_ops->get_transition_latency(cpu_dev);
	167	if (!latency)
	168	latency = CPUFREQ_ETERNAL;
	169
	170	policy->cpuinfo.transition_latency = latency;
	171
	172	policy->fast_switch_possible = false;
	173	return 0;
	174
343a8d17 SH	175	out_free_cpufreq_table:
	176	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
	177	out_free_priv:
	178	kfree(priv);
	179	out_free_opp:
1690d8bb	180	dev_pm_opp_remove_all_dynamic(cpu_dev);
343a8d17	181
d9975b0b	182	return ret;
8def3103 SH	183	}
8def3103 SH	184
343a8d17 SH	185	static int scpi_cpufreq_exit(struct cpufreq_policy *policy)
	186	{
	187	struct scpi_data *priv = policy->driver_data;
	188
	189	cpufreq_cooling_unregister(priv->cdev);
	190	clk_put(priv->clk);
	191	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
	192	kfree(priv);
1690d8bb	193	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);
343a8d17 SH	194
	195	return 0;
	196	}
	197
	198	static void scpi_cpufreq_ready(struct cpufreq_policy *policy)
	199	{
	200	struct scpi_data *priv = policy->driver_data;
343a8d17	201
eb85c50c	202	priv->cdev = of_cpufreq_cooling_register(policy);
343a8d17 SH	203	}
	204
	205	static struct cpufreq_driver scpi_cpufreq_driver = {
	206	.name = "scpi-cpufreq",
	207	.flags = CPUFREQ_STICKY \| CPUFREQ_HAVE_GOVERNOR_PER_POLICY \|
	208	CPUFREQ_NEED_INITIAL_FREQ_CHECK,
	209	.verify = cpufreq_generic_frequency_table_verify,
	210	.attr = cpufreq_generic_attr,
	211	.get = scpi_cpufreq_get_rate,
	212	.init = scpi_cpufreq_init,
	213	.exit = scpi_cpufreq_exit,
	214	.ready = scpi_cpufreq_ready,
	215	.target_index = scpi_cpufreq_set_target,
8def3103 SH	216	};
	217
	218	static int scpi_cpufreq_probe(struct platform_device *pdev)
	219	{
343a8d17 SH	220	int ret;
343a8d17 SH	221
8def3103 SH	222	scpi_ops = get_scpi_ops();
	223	if (!scpi_ops)
	224	return -EIO;
	225
343a8d17 SH	226	ret = cpufreq_register_driver(&scpi_cpufreq_driver);
	227	if (ret)
	228	dev_err(&pdev->dev, "%s: registering cpufreq failed, err: %d\n",
	229	__func__, ret);
	230	return ret;
8def3103 SH	231	}
	232
	233	static int scpi_cpufreq_remove(struct platform_device *pdev)
	234	{
343a8d17	235	cpufreq_unregister_driver(&scpi_cpufreq_driver);
8def3103 SH	236	scpi_ops = NULL;
	237	return 0;
	238	}
	239
	240	static struct platform_driver scpi_cpufreq_platdrv = {
	241	.driver = {
	242	.name = "scpi-cpufreq",
8def3103 SH	243	},
	244	.probe = scpi_cpufreq_probe,
	245	.remove = scpi_cpufreq_remove,
	246	};
	247	module_platform_driver(scpi_cpufreq_platdrv);
	248
	249	MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
	250	MODULE_DESCRIPTION("ARM SCPI CPUFreq interface driver");
	251	MODULE_LICENSE("GPL v2");