1212635Smav// SPDX-License-Identifier: GPL-2.0-only 2212635Smav/* 3212635Smav * amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias 4212635Smav * for the ondemand governor. 5212635Smav * 6212635Smav * Copyright (C) 2013 Advanced Micro Devices, Inc. 7212635Smav * 8212635Smav * Author: Jacob Shin <jacob.shin@amd.com> 9212635Smav */ 10212635Smav 11212635Smav#include <linux/kernel.h> 12212635Smav#include <linux/module.h> 13212635Smav#include <linux/types.h> 14212635Smav#include <linux/pci.h> 15212635Smav#include <linux/percpu-defs.h> 16212635Smav#include <linux/init.h> 17212635Smav#include <linux/mod_devicetable.h> 18212635Smav 19212635Smav#include <asm/msr.h> 20212635Smav#include <asm/cpufeature.h> 21212635Smav#include <asm/cpu_device_id.h> 22212635Smav 23212635Smav#include "cpufreq_ondemand.h" 24212635Smav 25212635Smav#define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL 0xc0010080 26212635Smav#define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE 0xc0010081 27232919Smav#define CLASS_CODE_SHIFT 56 28222286Sru#define POWERSAVE_BIAS_MAX 1000 29212635Smav#define POWERSAVE_BIAS_DEF 400 30212635Smav 31212635Smavstruct cpu_data_t { 32212635Smav u64 actual; 33212635Smav u64 reference; 34212635Smav unsigned int freq_prev; 35212635Smav}; 36212635Smav 37212635Smavstatic DEFINE_PER_CPU(struct cpu_data_t, cpu_data); 38212635Smav 39212635Smavstatic unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy, 40212635Smav unsigned int freq_next, 41212635Smav unsigned int relation) 42212635Smav{ 43212635Smav int sensitivity; 44212635Smav long d_actual, d_reference; 45212635Smav struct msr actual, reference; 46212635Smav struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu); 47212635Smav struct policy_dbs_info *policy_dbs = policy->governor_data; 48212635Smav struct dbs_data *od_data = policy_dbs->dbs_data; 49228575Smav struct od_dbs_tuners *od_tuners = od_data->tuners; 50228575Smav 51212635Smav if (!policy->freq_table) 52228575Smav return freq_next; 53228575Smav 54228575Smav rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, 55228575Smav &actual.l, &actual.h); 56212635Smav rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE, 57228575Smav &reference.l, &reference.h); 58228575Smav actual.h &= 0x00ffffff; 59228575Smav reference.h &= 0x00ffffff; 60228575Smav 61228575Smav /* counter wrapped around, so stay on current frequency */ 62228575Smav if (actual.q < data->actual || reference.q < data->reference) { 63212635Smav freq_next = policy->cur; 64228575Smav goto out; 65212635Smav } 66212635Smav 67212635Smav d_actual = actual.q - data->actual; 68212635Smav d_reference = reference.q - data->reference; 69212635Smav 70212635Smav /* divide by 0, so stay on current frequency as well */ 71212635Smav if (d_reference == 0) { 72212635Smav freq_next = policy->cur; 73212635Smav goto out; 74212635Smav } 75212635Smav 76212635Smav sensitivity = POWERSAVE_BIAS_MAX - 77212635Smav (POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference); 78212635Smav 79212635Smav clamp(sensitivity, 0, POWERSAVE_BIAS_MAX); 80212635Smav 81212635Smav /* this workload is not CPU bound, so choose a lower freq */ 82212635Smav if (sensitivity < od_tuners->powersave_bias) { 83212635Smav if (data->freq_prev == policy->cur) 84212635Smav freq_next = policy->cur; 85212635Smav 86212635Smav if (freq_next > policy->cur) 87212635Smav freq_next = policy->cur; 88212635Smav else if (freq_next < policy->cur) 89228575Smav freq_next = policy->min; 90228575Smav else { 91228575Smav unsigned int index; 92212635Smav 93228575Smav index = cpufreq_table_find_index_h(policy, 94212635Smav policy->cur - 1, 95228575Smav relation & CPUFREQ_RELATION_E); 96212635Smav freq_next = policy->freq_table[index].frequency; 97212635Smav } 98212635Smav 99212635Smav data->freq_prev = freq_next; 100212635Smav } else 101212635Smav data->freq_prev = 0; 102212635Smav 103212635Smavout: 104212635Smav data->actual = actual.q; 105212635Smav data->reference = reference.q; 106212635Smav return freq_next; 107212635Smav} 108228575Smav 109212635Smavstatic int __init amd_freq_sensitivity_init(void) 110212635Smav{ 111228575Smav u64 val; 112212635Smav struct pci_dev *pcidev; 113212635Smav unsigned int pci_vendor; 114212635Smav 115212635Smav if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) 116212635Smav pci_vendor = PCI_VENDOR_ID_AMD; 117212635Smav else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) 118212635Smav pci_vendor = PCI_VENDOR_ID_HYGON; 119212635Smav else 120228575Smav return -ENODEV; 121212635Smav 122212635Smav pcidev = pci_get_device(pci_vendor, 123212635Smav PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL); 124212635Smav 125212635Smav if (!pcidev) { 126212635Smav if (!boot_cpu_has(X86_FEATURE_PROC_FEEDBACK)) 127212635Smav return -ENODEV; 128212635Smav } else { 129212635Smav pci_dev_put(pcidev); 130212635Smav } 131212635Smav 132228575Smav if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val)) 133228575Smav return -ENODEV; 134228575Smav 135228575Smav if (!(val >> CLASS_CODE_SHIFT)) 136228575Smav return -ENODEV; 137228575Smav 138212635Smav od_register_powersave_bias_handler(amd_powersave_bias_target, 139212635Smav POWERSAVE_BIAS_DEF); 140212635Smav return 0; 141228575Smav} 142228575Smavlate_initcall(amd_freq_sensitivity_init); 143228575Smav 144212635Smavstatic void __exit amd_freq_sensitivity_exit(void) 145212635Smav{ 146212635Smav od_unregister_powersave_bias_handler(); 147212635Smav} 148228735Smavmodule_exit(amd_freq_sensitivity_exit); 149228575Smav 150212779Smavstatic const struct x86_cpu_id __maybe_unused amd_freq_sensitivity_ids[] = { 151228731Smav X86_MATCH_FEATURE(X86_FEATURE_PROC_FEEDBACK, NULL), 152228741Smav {} 153228731Smav}; 154MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids); 155 156MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>"); 157MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for " 158 "the ondemand governor."); 159MODULE_LICENSE("GPL"); 160