157 lines
4.0 KiB
C
157 lines
4.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* amd_freq_sensitivity.c: AMD frequency sensitivity feedback powersave bias
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* for the ondemand governor.
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*
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* Copyright (C) 2013 Advanced Micro Devices, Inc.
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*
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* Author: Jacob Shin <jacob.shin@amd.com>
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/pci.h>
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#include <linux/percpu-defs.h>
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#include <linux/init.h>
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#include <linux/mod_devicetable.h>
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#include <asm/msr.h>
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#include <asm/cpufeature.h>
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#include <asm/cpu_device_id.h>
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#include "cpufreq_ondemand.h"
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#define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL 0xc0010080
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#define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE 0xc0010081
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#define CLASS_CODE_SHIFT 56
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#define POWERSAVE_BIAS_MAX 1000
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#define POWERSAVE_BIAS_DEF 400
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struct cpu_data_t {
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u64 actual;
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u64 reference;
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unsigned int freq_prev;
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};
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static DEFINE_PER_CPU(struct cpu_data_t, cpu_data);
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static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
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unsigned int freq_next,
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unsigned int relation)
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{
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int sensitivity;
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long d_actual, d_reference;
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struct msr actual, reference;
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struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu);
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struct policy_dbs_info *policy_dbs = policy->governor_data;
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struct dbs_data *od_data = policy_dbs->dbs_data;
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struct od_dbs_tuners *od_tuners = od_data->tuners;
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if (!policy->freq_table)
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return freq_next;
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rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL,
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&actual.l, &actual.h);
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rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE,
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&reference.l, &reference.h);
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actual.h &= 0x00ffffff;
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reference.h &= 0x00ffffff;
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/* counter wrapped around, so stay on current frequency */
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if (actual.q < data->actual || reference.q < data->reference) {
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freq_next = policy->cur;
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goto out;
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}
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d_actual = actual.q - data->actual;
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d_reference = reference.q - data->reference;
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/* divide by 0, so stay on current frequency as well */
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if (d_reference == 0) {
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freq_next = policy->cur;
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goto out;
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}
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sensitivity = POWERSAVE_BIAS_MAX -
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(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);
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clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
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/* this workload is not CPU bound, so choose a lower freq */
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if (sensitivity < od_tuners->powersave_bias) {
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if (data->freq_prev == policy->cur)
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freq_next = policy->cur;
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if (freq_next > policy->cur)
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freq_next = policy->cur;
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else if (freq_next < policy->cur)
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freq_next = policy->min;
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else {
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unsigned int index;
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index = cpufreq_table_find_index_h(policy,
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policy->cur - 1);
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freq_next = policy->freq_table[index].frequency;
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}
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data->freq_prev = freq_next;
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} else
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data->freq_prev = 0;
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out:
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data->actual = actual.q;
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data->reference = reference.q;
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return freq_next;
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}
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static int __init amd_freq_sensitivity_init(void)
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{
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u64 val;
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struct pci_dev *pcidev;
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unsigned int pci_vendor;
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if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
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pci_vendor = PCI_VENDOR_ID_AMD;
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else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
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pci_vendor = PCI_VENDOR_ID_HYGON;
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else
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return -ENODEV;
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pcidev = pci_get_device(pci_vendor,
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PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);
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if (!pcidev) {
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if (!boot_cpu_has(X86_FEATURE_PROC_FEEDBACK))
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return -ENODEV;
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}
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if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
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return -ENODEV;
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if (!(val >> CLASS_CODE_SHIFT))
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return -ENODEV;
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od_register_powersave_bias_handler(amd_powersave_bias_target,
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POWERSAVE_BIAS_DEF);
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return 0;
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}
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late_initcall(amd_freq_sensitivity_init);
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static void __exit amd_freq_sensitivity_exit(void)
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{
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od_unregister_powersave_bias_handler();
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}
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module_exit(amd_freq_sensitivity_exit);
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static const struct x86_cpu_id __maybe_unused amd_freq_sensitivity_ids[] = {
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X86_MATCH_FEATURE(X86_FEATURE_PROC_FEEDBACK, NULL),
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{}
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};
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MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);
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MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>");
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MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
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"the ondemand governor.");
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MODULE_LICENSE("GPL");
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