GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / cpufreq / amd_freq_sensitivity.c
1 // SPDX-License-Identifier: GPL-2.0-only
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 <jacob.shin@amd.com>
9  */
10
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/pci.h>
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>
21 #include <asm/cpu_device_id.h>
22
23 #include "cpufreq_ondemand.h"
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);
47         struct policy_dbs_info *policy_dbs = policy->governor_data;
48         struct dbs_data *od_data = policy_dbs->dbs_data;
49         struct od_dbs_tuners *od_tuners = od_data->tuners;
50
51         if (!policy->freq_table)
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
93                         index = cpufreq_table_find_index_h(policy,
94                                                            policy->cur - 1,
95                                                            relation & CPUFREQ_RELATION_E);
96                         freq_next = policy->freq_table[index].frequency;
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;
112         struct pci_dev *pcidev;
113         unsigned int pci_vendor;
114
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
120                 return -ENODEV;
121
122         pcidev = pci_get_device(pci_vendor,
123                         PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);
124
125         if (!pcidev) {
126                 if (!boot_cpu_has(X86_FEATURE_PROC_FEEDBACK))
127                         return -ENODEV;
128         }
129
130         if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
131                 return -ENODEV;
132
133         if (!(val >> CLASS_CODE_SHIFT))
134                 return -ENODEV;
135
136         od_register_powersave_bias_handler(amd_powersave_bias_target,
137                         POWERSAVE_BIAS_DEF);
138         return 0;
139 }
140 late_initcall(amd_freq_sensitivity_init);
141
142 static void __exit amd_freq_sensitivity_exit(void)
143 {
144         od_unregister_powersave_bias_handler();
145 }
146 module_exit(amd_freq_sensitivity_exit);
147
148 static const struct x86_cpu_id __maybe_unused amd_freq_sensitivity_ids[] = {
149         X86_MATCH_FEATURE(X86_FEATURE_PROC_FEEDBACK, NULL),
150         {}
151 };
152 MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);
153
154 MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>");
155 MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
156                 "the ondemand governor.");
157 MODULE_LICENSE("GPL");