[linux.git] / drivers / cpufreq / amd_freq_sensitivity.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias
 *                         for the ondemand governor.
 *
 * Copyright (C) 2013 Advanced Micro Devices, Inc.
 *
 * Author: Jacob Shin <[email protected]>
 */

#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 <asm/cpu_device_id.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,
							   relation & CPUFREQ_RELATION_E);
			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 (!boot_cpu_has(X86_FEATURE_PROC_FEEDBACK))
			return -ENODEV;
	} else {
		pci_dev_put(pcidev);
	}

	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 __maybe_unused amd_freq_sensitivity_ids[] = {
	X86_MATCH_FEATURE(X86_FEATURE_PROC_FEEDBACK, NULL),
	{}
};
MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);

MODULE_AUTHOR("Jacob Shin <[email protected]>");
MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
		"the ondemand governor.");
MODULE_LICENSE("GPL");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
9c5320c8 JS	2	/*
	3	* amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias
	4	* for the ondemand governor.
	5	*
	6	* Copyright (C) 2013 Advanced Micro Devices, Inc.
	7	*
	8	* Author: Jacob Shin <[email protected]>
9c5320c8 JS	9	*/
	10
	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
	13	#include <linux/types.h>
59a3b3a8	14	#include <linux/pci.h>
9c5320c8 JS	15	#include <linux/percpu-defs.h>
	16	#include <linux/init.h>
	17	#include <linux/mod_devicetable.h>
	18
	19	#include <asm/msr.h>
	20	#include <asm/cpufeature.h>
ba5bade4	21	#include <asm/cpu_device_id.h>
9c5320c8	22
7d5a9956	23	#include "cpufreq_ondemand.h"
9c5320c8 JS	24
	25	#define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL 0xc0010080
	26	#define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE 0xc0010081
	27	#define CLASS_CODE_SHIFT 56
	28	#define POWERSAVE_BIAS_MAX 1000
	29	#define POWERSAVE_BIAS_DEF 400
	30
	31	struct cpu_data_t {
	32	u64 actual;
	33	u64 reference;
	34	unsigned int freq_prev;
	35	};
	36
	37	static DEFINE_PER_CPU(struct cpu_data_t, cpu_data);
	38
	39	static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
	40	unsigned int freq_next,
	41	unsigned int relation)
	42	{
	43	int sensitivity;
	44	long d_actual, d_reference;
	45	struct msr actual, reference;
	46	struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu);
bc505475 RW	47	struct policy_dbs_info *policy_dbs = policy->governor_data;
bc505475 RW	48	struct dbs_data *od_data = policy_dbs->dbs_data;
9c5320c8	49	struct od_dbs_tuners *od_tuners = od_data->tuners;
9c5320c8	50
34ac5d7a	51	if (!policy->freq_table)
9c5320c8 JS	52	return freq_next;
	53
	54	rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL,
	55	&actual.l, &actual.h);
	56	rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE,
	57	&reference.l, &reference.h);
	58	actual.h &= 0x00ffffff;
	59	reference.h &= 0x00ffffff;
	60
	61	/* counter wrapped around, so stay on current frequency */
	62	if (actual.q < data->actual \|\| reference.q < data->reference) {
	63	freq_next = policy->cur;
	64	goto out;
	65	}
	66
	67	d_actual = actual.q - data->actual;
	68	d_reference = reference.q - data->reference;
	69
	70	/* divide by 0, so stay on current frequency as well */
	71	if (d_reference == 0) {
	72	freq_next = policy->cur;
	73	goto out;
	74	}
	75
	76	sensitivity = POWERSAVE_BIAS_MAX -
	77	(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);
	78
	79	clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
	80
	81	/* this workload is not CPU bound, so choose a lower freq */
	82	if (sensitivity < od_tuners->powersave_bias) {
	83	if (data->freq_prev == policy->cur)
	84	freq_next = policy->cur;
	85
	86	if (freq_next > policy->cur)
	87	freq_next = policy->cur;
	88	else if (freq_next < policy->cur)
	89	freq_next = policy->min;
	90	else {
	91	unsigned int index;
	92
82577360	93	index = cpufreq_table_find_index_h(policy,
1f39fa0d VD	94	policy->cur - 1,
1f39fa0d VD	95	relation & CPUFREQ_RELATION_E);
34ac5d7a	96	freq_next = policy->freq_table[index].frequency;
9c5320c8 JS	97	}
	98
	99	data->freq_prev = freq_next;
	100	} else
	101	data->freq_prev = 0;
	102
	103	out:
	104	data->actual = actual.q;
	105	data->reference = reference.q;
	106	return freq_next;
	107	}
	108
	109	static int __init amd_freq_sensitivity_init(void)
	110	{
	111	u64 val;
59a3b3a8	112	struct pci_dev *pcidev;
cc9690cf	113	unsigned int pci_vendor;
9c5320c8	114
cc9690cf PW	115	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
	116	pci_vendor = PCI_VENDOR_ID_AMD;
	117	else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
	118	pci_vendor = PCI_VENDOR_ID_HYGON;
	119	else
9c5320c8 JS	120	return -ENODEV;
9c5320c8 JS	121
cc9690cf	122	pcidev = pci_get_device(pci_vendor,
59a3b3a8 AA	123	PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);
	124
	125	if (!pcidev) {
108ec36b	126	if (!boot_cpu_has(X86_FEATURE_PROC_FEEDBACK))
59a3b3a8	127	return -ENODEV;
91fda1f8 XW	128	} else {
91fda1f8 XW	129	pci_dev_put(pcidev);
59a3b3a8	130	}
9c5320c8 JS	131
	132	if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
	133	return -ENODEV;
	134
	135	if (!(val >> CLASS_CODE_SHIFT))
	136	return -ENODEV;
	137
	138	od_register_powersave_bias_handler(amd_powersave_bias_target,
	139	POWERSAVE_BIAS_DEF);
	140	return 0;
	141	}
	142	late_initcall(amd_freq_sensitivity_init);
	143
	144	static void __exit amd_freq_sensitivity_exit(void)
	145	{
	146	od_unregister_powersave_bias_handler();
	147	}
	148	module_exit(amd_freq_sensitivity_exit);
	149
52fe0b16	150	static const struct x86_cpu_id __maybe_unused amd_freq_sensitivity_ids[] = {
b11d77fa	151	X86_MATCH_FEATURE(X86_FEATURE_PROC_FEEDBACK, NULL),
9c5320c8 JS	152	{}
	153	};
	154	MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);
	155
	156	MODULE_AUTHOR("Jacob Shin <[email protected]>");
	157	MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
	158	"the ondemand governor.");
	159	MODULE_LICENSE("GPL");