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

/*
 * amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias
 *                         for the ondemand governor.
 *
 * Copyright (C) 2013 Advanced Micro Devices, Inc.
 *
 * Author: Jacob Shin <jacob.shin@amd.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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/percpu-defs.h>
#include <linux/init.h>
#include <linux/mod_devicetable.h>

#include <asm/msr.h>
#include <asm/cpufeature.h>

#include "cpufreq_ondemand.h"

#define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL	0xc0010080
#define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE	0xc0010081
#define CLASS_CODE_SHIFT			56
#define POWERSAVE_BIAS_MAX			1000
#define POWERSAVE_BIAS_DEF			400

struct cpu_data_t {
	u64 actual;
	u64 reference;
	unsigned int freq_prev;
};

static DEFINE_PER_CPU(struct cpu_data_t, cpu_data);

static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
					      unsigned int freq_next,
					      unsigned int relation)
{
	int sensitivity;
	long d_actual, d_reference;
	struct msr actual, reference;
	struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu);
	struct policy_dbs_info *policy_dbs = policy->governor_data;
	struct dbs_data *od_data = policy_dbs->dbs_data;
	struct od_dbs_tuners *od_tuners = od_data->tuners;

	if (!policy->freq_table)
		return freq_next;

	rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL,
		&actual.l, &actual.h);
	rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE,
		&reference.l, &reference.h);
	actual.h &= 0x00ffffff;
	reference.h &= 0x00ffffff;

	/* counter wrapped around, so stay on current frequency */
	if (actual.q < data->actual || reference.q < data->reference) {
		freq_next = policy->cur;
		goto out;
	}

	d_actual = actual.q - data->actual;
	d_reference = reference.q - data->reference;

	/* divide by 0, so stay on current frequency as well */
	if (d_reference == 0) {
		freq_next = policy->cur;
		goto out;
	}

	sensitivity = POWERSAVE_BIAS_MAX -
		(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);

	clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);

	/* this workload is not CPU bound, so choose a lower freq */
	if (sensitivity < od_tuners->powersave_bias) {
		if (data->freq_prev == policy->cur)
			freq_next = policy->cur;

		if (freq_next > policy->cur)
			freq_next = policy->cur;
		else if (freq_next < policy->cur)
			freq_next = policy->min;
		else {
			unsigned int index;

			index = cpufreq_table_find_index_h(policy,
							   policy->cur - 1);
			freq_next = policy->freq_table[index].frequency;
		}

		data->freq_prev = freq_next;
	} else
		data->freq_prev = 0;

out:
	data->actual = actual.q;
	data->reference = reference.q;
	return freq_next;
}

static int __init amd_freq_sensitivity_init(void)
{
	u64 val;
	struct pci_dev *pcidev;
	unsigned int pci_vendor;

	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
		pci_vendor = PCI_VENDOR_ID_AMD;
	else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
		pci_vendor = PCI_VENDOR_ID_HYGON;
	else
		return -ENODEV;

	pcidev = pci_get_device(pci_vendor,
			PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);

	if (!pcidev) {
		if (!static_cpu_has(X86_FEATURE_PROC_FEEDBACK))
			return -ENODEV;
	}

	if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
		return -ENODEV;

	if (!(val >> CLASS_CODE_SHIFT))
		return -ENODEV;

	od_register_powersave_bias_handler(amd_powersave_bias_target,
			POWERSAVE_BIAS_DEF);
	return 0;
}
late_initcall(amd_freq_sensitivity_init);

static void __exit amd_freq_sensitivity_exit(void)
{
	od_unregister_powersave_bias_handler();
}
module_exit(amd_freq_sensitivity_exit);

static const struct x86_cpu_id amd_freq_sensitivity_ids[] = {
	X86_FEATURE_MATCH(X86_FEATURE_PROC_FEEDBACK),
	{}
};
MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);

MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>");
MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
		"the ondemand governor.");
MODULE_LICENSE("GPL");
Commit	Line	Data
9c5320c8 JS	1	/*
	2	* amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias
	3	* for the ondemand governor.
	4	*
	5	* Copyright (C) 2013 Advanced Micro Devices, Inc.
	6	*
	7	* Author: Jacob Shin <jacob.shin@amd.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
	14	#include <linux/kernel.h>
	15	#include <linux/module.h>
	16	#include <linux/types.h>
59a3b3a8	17	#include <linux/pci.h>
9c5320c8 JS	18	#include <linux/percpu-defs.h>
	19	#include <linux/init.h>
	20	#include <linux/mod_devicetable.h>
	21
	22	#include <asm/msr.h>
	23	#include <asm/cpufeature.h>
	24
7d5a9956	25	#include "cpufreq_ondemand.h"
9c5320c8 JS	26
	27	#define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL 0xc0010080
	28	#define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE 0xc0010081
	29	#define CLASS_CODE_SHIFT 56
	30	#define POWERSAVE_BIAS_MAX 1000
	31	#define POWERSAVE_BIAS_DEF 400
	32
	33	struct cpu_data_t {
	34	u64 actual;
	35	u64 reference;
	36	unsigned int freq_prev;
	37	};
	38
	39	static DEFINE_PER_CPU(struct cpu_data_t, cpu_data);
	40
	41	static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
	42	unsigned int freq_next,
	43	unsigned int relation)
	44	{
	45	int sensitivity;
	46	long d_actual, d_reference;
	47	struct msr actual, reference;
	48	struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu);
bc505475 RW	49	struct policy_dbs_info *policy_dbs = policy->governor_data;
bc505475 RW	50	struct dbs_data *od_data = policy_dbs->dbs_data;
9c5320c8	51	struct od_dbs_tuners *od_tuners = od_data->tuners;
9c5320c8	52
34ac5d7a	53	if (!policy->freq_table)
9c5320c8 JS	54	return freq_next;
	55
	56	rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL,
	57	&actual.l, &actual.h);
	58	rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE,
	59	&reference.l, &reference.h);
	60	actual.h &= 0x00ffffff;
	61	reference.h &= 0x00ffffff;
	62
	63	/* counter wrapped around, so stay on current frequency */
	64	if (actual.q < data->actual \|\| reference.q < data->reference) {
	65	freq_next = policy->cur;
	66	goto out;
	67	}
	68
	69	d_actual = actual.q - data->actual;
	70	d_reference = reference.q - data->reference;
	71
	72	/* divide by 0, so stay on current frequency as well */
	73	if (d_reference == 0) {
	74	freq_next = policy->cur;
	75	goto out;
	76	}
	77
	78	sensitivity = POWERSAVE_BIAS_MAX -
	79	(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);
	80
	81	clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
	82
	83	/* this workload is not CPU bound, so choose a lower freq */
	84	if (sensitivity < od_tuners->powersave_bias) {
	85	if (data->freq_prev == policy->cur)
	86	freq_next = policy->cur;
	87
	88	if (freq_next > policy->cur)
	89	freq_next = policy->cur;
	90	else if (freq_next < policy->cur)
	91	freq_next = policy->min;
	92	else {
	93	unsigned int index;
	94
82577360 VK	95	index = cpufreq_table_find_index_h(policy,
82577360 VK	96	policy->cur - 1);
34ac5d7a	97	freq_next = policy->freq_table[index].frequency;
9c5320c8 JS	98	}
	99
	100	data->freq_prev = freq_next;
	101	} else
	102	data->freq_prev = 0;
	103
	104	out:
	105	data->actual = actual.q;
	106	data->reference = reference.q;
	107	return freq_next;
	108	}
	109
	110	static int __init amd_freq_sensitivity_init(void)
	111	{
	112	u64 val;
59a3b3a8	113	struct pci_dev *pcidev;
cc9690cf	114	unsigned int pci_vendor;
9c5320c8	115
cc9690cf PW	116	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
	117	pci_vendor = PCI_VENDOR_ID_AMD;
	118	else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
	119	pci_vendor = PCI_VENDOR_ID_HYGON;
	120	else
9c5320c8 JS	121	return -ENODEV;
9c5320c8 JS	122
cc9690cf	123	pcidev = pci_get_device(pci_vendor,
59a3b3a8 AA	124	PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);
	125
	126	if (!pcidev) {
	127	if (!static_cpu_has(X86_FEATURE_PROC_FEEDBACK))
	128	return -ENODEV;
	129	}
9c5320c8 JS	130
	131	if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
	132	return -ENODEV;
	133
	134	if (!(val >> CLASS_CODE_SHIFT))
	135	return -ENODEV;
	136
	137	od_register_powersave_bias_handler(amd_powersave_bias_target,
	138	POWERSAVE_BIAS_DEF);
	139	return 0;
	140	}
	141	late_initcall(amd_freq_sensitivity_init);
	142
	143	static void __exit amd_freq_sensitivity_exit(void)
	144	{
	145	od_unregister_powersave_bias_handler();
	146	}
	147	module_exit(amd_freq_sensitivity_exit);
	148
	149	static const struct x86_cpu_id amd_freq_sensitivity_ids[] = {
	150	X86_FEATURE_MATCH(X86_FEATURE_PROC_FEEDBACK),
	151	{}
	152	};
	153	MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);
	154
	155	MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>");
	156	MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
	157	"the ondemand governor.");
	158	MODULE_LICENSE("GPL");