[mirror_ubuntu-artful-kernel.git] / drivers / cpufreq / cppc_cpufreq.c

/*
 * CPPC (Collaborative Processor Performance Control) driver for
 * interfacing with the CPUfreq layer and governors. See
 * cppc_acpi.c for CPPC specific methods.
 *
 * (C) Copyright 2014, 2015 Linaro Ltd.
 * Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; version 2
 * of the License.
 */

#define pr_fmt(fmt)	"CPPC Cpufreq:"	fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/dmi.h>
#include <linux/vmalloc.h>

#include <asm/unaligned.h>

#include <acpi/cppc_acpi.h>

/* Minimum struct length needed for the DMI processor entry we want */
#define DMI_ENTRY_PROCESSOR_MIN_LENGTH	48

/* Offest in the DMI processor structure for the max frequency */
#define DMI_PROCESSOR_MAX_SPEED  0x14

/*
 * These structs contain information parsed from per CPU
 * ACPI _CPC structures.
 * e.g. For each CPU the highest, lowest supported
 * performance capabilities, desired performance level
 * requested etc.
 */
static struct cppc_cpudata **all_cpu_data;

/* Capture the max KHz from DMI */
static u64 cppc_dmi_max_khz;

/* Callback function used to retrieve the max frequency from DMI */
static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
{
	const u8 *dmi_data = (const u8 *)dm;
	u16 *mhz = (u16 *)private;

	if (dm->type == DMI_ENTRY_PROCESSOR &&
	    dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
		u16 val = (u16)get_unaligned((const u16 *)
				(dmi_data + DMI_PROCESSOR_MAX_SPEED));
		*mhz = val > *mhz ? val : *mhz;
	}
}

/* Look up the max frequency in DMI */
static u64 cppc_get_dmi_max_khz(void)
{
	u16 mhz = 0;

	dmi_walk(cppc_find_dmi_mhz, &mhz);

	/*
	 * Real stupid fallback value, just in case there is no
	 * actual value set.
	 */
	mhz = mhz ? mhz : 1;

	return (1000 * mhz);
}

static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
		unsigned int target_freq,
		unsigned int relation)
{
	struct cppc_cpudata *cpu;
	struct cpufreq_freqs freqs;
	u32 desired_perf;
	int ret = 0;

	cpu = all_cpu_data[policy->cpu];

	desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
	/* Return if it is exactly the same perf */
	if (desired_perf == cpu->perf_ctrls.desired_perf)
		return ret;

	cpu->perf_ctrls.desired_perf = desired_perf;
	freqs.old = policy->cur;
	freqs.new = target_freq;

	cpufreq_freq_transition_begin(policy, &freqs);
	ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
	cpufreq_freq_transition_end(policy, &freqs, ret != 0);

	if (ret)
		pr_debug("Failed to set target on CPU:%d. ret:%d\n",
				cpu->cpu, ret);

	return ret;
}

static int cppc_verify_policy(struct cpufreq_policy *policy)
{
	cpufreq_verify_within_cpu_limits(policy);
	return 0;
}

static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
{
	int cpu_num = policy->cpu;
	struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
	int ret;

	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;

	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	if (ret)
		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
				cpu->perf_caps.lowest_perf, cpu_num, ret);
}

static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
	struct cppc_cpudata *cpu;
	unsigned int cpu_num = policy->cpu;
	int ret = 0;

	cpu = all_cpu_data[policy->cpu];

	cpu->cpu = cpu_num;
	ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);

	if (ret) {
		pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
				cpu_num, ret);
		return ret;
	}

	cppc_dmi_max_khz = cppc_get_dmi_max_khz();

	/*
	 * Set min to lowest nonlinear perf to avoid any efficiency penalty (see
	 * Section 8.4.7.1.1.5 of ACPI 6.1 spec)
	 */
	policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz /
		cpu->perf_caps.highest_perf;
	policy->max = cppc_dmi_max_khz;

	/*
	 * Set cpuinfo.min_freq to Lowest to make the full range of performance
	 * available if userspace wants to use any perf between lowest & lowest
	 * nonlinear perf
	 */
	policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz /
		cpu->perf_caps.highest_perf;
	policy->cpuinfo.max_freq = cppc_dmi_max_khz;

	policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
	policy->shared_type = cpu->shared_type;

	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
		cpumask_copy(policy->cpus, cpu->shared_cpu_map);
	else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
		/* Support only SW_ANY for now. */
		pr_debug("Unsupported CPU co-ord type\n");
		return -EFAULT;
	}

	cpumask_set_cpu(policy->cpu, policy->cpus);
	cpu->cur_policy = policy;

	/* Set policy->cur to max now. The governors will adjust later. */
	policy->cur = cppc_dmi_max_khz;
	cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;

	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	if (ret)
		pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
				cpu->perf_caps.highest_perf, cpu_num, ret);

	return ret;
}

static struct cpufreq_driver cppc_cpufreq_driver = {
	.flags = CPUFREQ_CONST_LOOPS,
	.verify = cppc_verify_policy,
	.target = cppc_cpufreq_set_target,
	.init = cppc_cpufreq_cpu_init,
	.stop_cpu = cppc_cpufreq_stop_cpu,
	.name = "cppc_cpufreq",
};

static int __init cppc_cpufreq_init(void)
{
	int i, ret = 0;
	struct cppc_cpudata *cpu;

	if (acpi_disabled)
		return -ENODEV;

	all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
	if (!all_cpu_data)
		return -ENOMEM;

	for_each_possible_cpu(i) {
		all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
		if (!all_cpu_data[i])
			goto out;

		cpu = all_cpu_data[i];
		if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
			goto out;
	}

	ret = acpi_get_psd_map(all_cpu_data);
	if (ret) {
		pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
		goto out;
	}

	ret = cpufreq_register_driver(&cppc_cpufreq_driver);
	if (ret)
		goto out;

	return ret;

out:
	for_each_possible_cpu(i)
		kfree(all_cpu_data[i]);

	kfree(all_cpu_data);
	return -ENODEV;
}

static void __exit cppc_cpufreq_exit(void)
{
	struct cppc_cpudata *cpu;
	int i;

	cpufreq_unregister_driver(&cppc_cpufreq_driver);

	for_each_possible_cpu(i) {
		cpu = all_cpu_data[i];
		free_cpumask_var(cpu->shared_cpu_map);
		kfree(cpu);
	}

	kfree(all_cpu_data);
}

module_exit(cppc_cpufreq_exit);
MODULE_AUTHOR("Ashwin Chaugule");
MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
MODULE_LICENSE("GPL");

late_initcall(cppc_cpufreq_init);

static const struct acpi_device_id cppc_acpi_ids[] = {
	{ACPI_PROCESSOR_DEVICE_HID, },
	{}
};

MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);
Commit	Line	Data
5477fb3b AC	1	/*
	2	* CPPC (Collaborative Processor Performance Control) driver for
	3	* interfacing with the CPUfreq layer and governors. See
	4	* cppc_acpi.c for CPPC specific methods.
	5	*
	6	* (C) Copyright 2014, 2015 Linaro Ltd.
	7	* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* as published by the Free Software Foundation; version 2
	12	* of the License.
	13	*/
	14
	15	#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
	16
	17	#include <linux/kernel.h>
	18	#include <linux/module.h>
	19	#include <linux/delay.h>
	20	#include <linux/cpu.h>
	21	#include <linux/cpufreq.h>
ad38677d	22	#include <linux/dmi.h>
5477fb3b AC	23	#include <linux/vmalloc.h>
5477fb3b AC	24
ad38677d AS	25	#include <asm/unaligned.h>
ad38677d AS	26
5477fb3b AC	27	#include <acpi/cppc_acpi.h>
5477fb3b AC	28
ad38677d AS	29	/* Minimum struct length needed for the DMI processor entry we want */
	30	#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
	31
	32	/* Offest in the DMI processor structure for the max frequency */
	33	#define DMI_PROCESSOR_MAX_SPEED 0x14
	34
5477fb3b AC	35	/*
	36	* These structs contain information parsed from per CPU
	37	* ACPI _CPC structures.
	38	* e.g. For each CPU the highest, lowest supported
	39	* performance capabilities, desired performance level
	40	* requested etc.
	41	*/
41dd6403	42	static struct cppc_cpudata **all_cpu_data;
5477fb3b	43
ad38677d AS	44	/* Capture the max KHz from DMI */
	45	static u64 cppc_dmi_max_khz;
	46
	47	/* Callback function used to retrieve the max frequency from DMI */
	48	static void cppc_find_dmi_mhz(const struct dmi_header dm, void private)
	49	{
	50	const u8 dmi_data = (const u8 )dm;
	51	u16 mhz = (u16 )private;
	52
	53	if (dm->type == DMI_ENTRY_PROCESSOR &&
	54	dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
	55	u16 val = (u16)get_unaligned((const u16 *)
	56	(dmi_data + DMI_PROCESSOR_MAX_SPEED));
	57	mhz = val > mhz ? val : *mhz;
	58	}
	59	}
	60
	61	/* Look up the max frequency in DMI */
	62	static u64 cppc_get_dmi_max_khz(void)
	63	{
	64	u16 mhz = 0;
	65
	66	dmi_walk(cppc_find_dmi_mhz, &mhz);
	67
	68	/*
	69	* Real stupid fallback value, just in case there is no
	70	* actual value set.
	71	*/
	72	mhz = mhz ? mhz : 1;
	73
	74	return (1000 * mhz);
	75	}
	76
5477fb3b AC	77	static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
	78	unsigned int target_freq,
	79	unsigned int relation)
	80	{
41dd6403	81	struct cppc_cpudata *cpu;
5477fb3b	82	struct cpufreq_freqs freqs;
c197d758	83	u32 desired_perf;
5477fb3b AC	84	int ret = 0;
	85
	86	cpu = all_cpu_data[policy->cpu];
	87
c197d758 HT	88	desired_perf = (u64)target_freq * cpu->perf_caps.highest_perf / cppc_dmi_max_khz;
	89	/* Return if it is exactly the same perf */
	90	if (desired_perf == cpu->perf_ctrls.desired_perf)
	91	return ret;
	92
	93	cpu->perf_ctrls.desired_perf = desired_perf;
5477fb3b AC	94	freqs.old = policy->cur;
	95	freqs.new = target_freq;
	96
	97	cpufreq_freq_transition_begin(policy, &freqs);
	98	ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
	99	cpufreq_freq_transition_end(policy, &freqs, ret != 0);
	100
	101	if (ret)
	102	pr_debug("Failed to set target on CPU:%d. ret:%d\n",
	103	cpu->cpu, ret);
	104
	105	return ret;
	106	}
	107
	108	static int cppc_verify_policy(struct cpufreq_policy *policy)
	109	{
	110	cpufreq_verify_within_cpu_limits(policy);
	111	return 0;
	112	}
	113
	114	static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
	115	{
	116	int cpu_num = policy->cpu;
41dd6403	117	struct cppc_cpudata *cpu = all_cpu_data[cpu_num];
5477fb3b AC	118	int ret;
	119
	120	cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
	121
	122	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	123	if (ret)
	124	pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
	125	cpu->perf_caps.lowest_perf, cpu_num, ret);
	126	}
	127
	128	static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
	129	{
41dd6403	130	struct cppc_cpudata *cpu;
5477fb3b AC	131	unsigned int cpu_num = policy->cpu;
	132	int ret = 0;
	133
	134	cpu = all_cpu_data[policy->cpu];
	135
	136	cpu->cpu = cpu_num;
	137	ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
	138
	139	if (ret) {
	140	pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
	141	cpu_num, ret);
	142	return ret;
	143	}
	144
ad38677d AS	145	cppc_dmi_max_khz = cppc_get_dmi_max_khz();
ad38677d AS	146
73808d0f PP	147	/*
	148	* Set min to lowest nonlinear perf to avoid any efficiency penalty (see
	149	* Section 8.4.7.1.1.5 of ACPI 6.1 spec)
	150	*/
	151	policy->min = cpu->perf_caps.lowest_nonlinear_perf * cppc_dmi_max_khz /
	152	cpu->perf_caps.highest_perf;
ad38677d	153	policy->max = cppc_dmi_max_khz;
73808d0f PP	154
	155	/*
	156	* Set cpuinfo.min_freq to Lowest to make the full range of performance
	157	* available if userspace wants to use any perf between lowest & lowest
	158	* nonlinear perf
	159	*/
	160	policy->cpuinfo.min_freq = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz /
	161	cpu->perf_caps.highest_perf;
	162	policy->cpuinfo.max_freq = cppc_dmi_max_khz;
	163
be8b88d7	164	policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
9dc17917	165	policy->shared_type = cpu->shared_type;
5477fb3b AC	166
	167	if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
	168	cpumask_copy(policy->cpus, cpu->shared_cpu_map);
9dc17917	169	else if (policy->shared_type == CPUFREQ_SHARED_TYPE_ALL) {
5477fb3b AC	170	/* Support only SW_ANY for now. */
	171	pr_debug("Unsupported CPU co-ord type\n");
	172	return -EFAULT;
	173	}
	174
	175	cpumask_set_cpu(policy->cpu, policy->cpus);
	176	cpu->cur_policy = policy;
	177
	178	/* Set policy->cur to max now. The governors will adjust later. */
ad38677d AS	179	policy->cur = cppc_dmi_max_khz;
ad38677d AS	180	cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
5477fb3b AC	181
	182	ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
	183	if (ret)
	184	pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
	185	cpu->perf_caps.highest_perf, cpu_num, ret);
	186
	187	return ret;
	188	}
	189
	190	static struct cpufreq_driver cppc_cpufreq_driver = {
	191	.flags = CPUFREQ_CONST_LOOPS,
	192	.verify = cppc_verify_policy,
	193	.target = cppc_cpufreq_set_target,
	194	.init = cppc_cpufreq_cpu_init,
	195	.stop_cpu = cppc_cpufreq_stop_cpu,
	196	.name = "cppc_cpufreq",
	197	};
	198
	199	static int __init cppc_cpufreq_init(void)
	200	{
	201	int i, ret = 0;
41dd6403	202	struct cppc_cpudata *cpu;
5477fb3b AC	203
	204	if (acpi_disabled)
	205	return -ENODEV;
	206
	207	all_cpu_data = kzalloc(sizeof(void ) num_possible_cpus(), GFP_KERNEL);
	208	if (!all_cpu_data)
	209	return -ENOMEM;
	210
	211	for_each_possible_cpu(i) {
41dd6403	212	all_cpu_data[i] = kzalloc(sizeof(struct cppc_cpudata), GFP_KERNEL);
5477fb3b AC	213	if (!all_cpu_data[i])
	214	goto out;
	215
	216	cpu = all_cpu_data[i];
	217	if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
	218	goto out;
	219	}
	220
	221	ret = acpi_get_psd_map(all_cpu_data);
	222	if (ret) {
	223	pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
	224	goto out;
	225	}
	226
	227	ret = cpufreq_register_driver(&cppc_cpufreq_driver);
	228	if (ret)
	229	goto out;
	230
	231	return ret;
	232
	233	out:
	234	for_each_possible_cpu(i)
efb2d3be	235	kfree(all_cpu_data[i]);
5477fb3b AC	236
	237	kfree(all_cpu_data);
	238	return -ENODEV;
	239	}
	240
a29a1e76 AC	241	static void __exit cppc_cpufreq_exit(void)
a29a1e76 AC	242	{
41dd6403	243	struct cppc_cpudata *cpu;
a29a1e76 AC	244	int i;
	245
	246	cpufreq_unregister_driver(&cppc_cpufreq_driver);
	247
	248	for_each_possible_cpu(i) {
	249	cpu = all_cpu_data[i];
	250	free_cpumask_var(cpu->shared_cpu_map);
	251	kfree(cpu);
	252	}
	253
	254	kfree(all_cpu_data);
	255	}
	256
	257	module_exit(cppc_cpufreq_exit);
	258	MODULE_AUTHOR("Ashwin Chaugule");
	259	MODULE_DESCRIPTION("CPUFreq driver based on the ACPI CPPC v5.0+ spec");
	260	MODULE_LICENSE("GPL");
	261
5477fb3b	262	late_initcall(cppc_cpufreq_init);
974f8649 PP	263
	264	static const struct acpi_device_id cppc_acpi_ids[] = {
	265	{ACPI_PROCESSOR_DEVICE_HID, },
	266	{}
	267	};
	268
	269	MODULE_DEVICE_TABLE(acpi, cppc_acpi_ids);