Merge tag 'gvt-next-fixes-2019-09-06' of https://github.com/intel/gvt-linux into...
[linux-2.6-block.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
22 #include "cpufreq_ondemand.h"
23
24 #define MSR_AMD64_FREQ_SENSITIVITY_ACTUAL       0xc0010080
25 #define MSR_AMD64_FREQ_SENSITIVITY_REFERENCE    0xc0010081
26 #define CLASS_CODE_SHIFT                        56
27 #define POWERSAVE_BIAS_MAX                      1000
28 #define POWERSAVE_BIAS_DEF                      400
29
30 struct cpu_data_t {
31         u64 actual;
32         u64 reference;
33         unsigned int freq_prev;
34 };
35
36 static DEFINE_PER_CPU(struct cpu_data_t, cpu_data);
37
38 static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
39                                               unsigned int freq_next,
40                                               unsigned int relation)
41 {
42         int sensitivity;
43         long d_actual, d_reference;
44         struct msr actual, reference;
45         struct cpu_data_t *data = &per_cpu(cpu_data, policy->cpu);
46         struct policy_dbs_info *policy_dbs = policy->governor_data;
47         struct dbs_data *od_data = policy_dbs->dbs_data;
48         struct od_dbs_tuners *od_tuners = od_data->tuners;
49
50         if (!policy->freq_table)
51                 return freq_next;
52
53         rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_ACTUAL,
54                 &actual.l, &actual.h);
55         rdmsr_on_cpu(policy->cpu, MSR_AMD64_FREQ_SENSITIVITY_REFERENCE,
56                 &reference.l, &reference.h);
57         actual.h &= 0x00ffffff;
58         reference.h &= 0x00ffffff;
59
60         /* counter wrapped around, so stay on current frequency */
61         if (actual.q < data->actual || reference.q < data->reference) {
62                 freq_next = policy->cur;
63                 goto out;
64         }
65
66         d_actual = actual.q - data->actual;
67         d_reference = reference.q - data->reference;
68
69         /* divide by 0, so stay on current frequency as well */
70         if (d_reference == 0) {
71                 freq_next = policy->cur;
72                 goto out;
73         }
74
75         sensitivity = POWERSAVE_BIAS_MAX -
76                 (POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);
77
78         clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
79
80         /* this workload is not CPU bound, so choose a lower freq */
81         if (sensitivity < od_tuners->powersave_bias) {
82                 if (data->freq_prev == policy->cur)
83                         freq_next = policy->cur;
84
85                 if (freq_next > policy->cur)
86                         freq_next = policy->cur;
87                 else if (freq_next < policy->cur)
88                         freq_next = policy->min;
89                 else {
90                         unsigned int index;
91
92                         index = cpufreq_table_find_index_h(policy,
93                                                            policy->cur - 1);
94                         freq_next = policy->freq_table[index].frequency;
95                 }
96
97                 data->freq_prev = freq_next;
98         } else
99                 data->freq_prev = 0;
100
101 out:
102         data->actual = actual.q;
103         data->reference = reference.q;
104         return freq_next;
105 }
106
107 static int __init amd_freq_sensitivity_init(void)
108 {
109         u64 val;
110         struct pci_dev *pcidev;
111         unsigned int pci_vendor;
112
113         if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
114                 pci_vendor = PCI_VENDOR_ID_AMD;
115         else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
116                 pci_vendor = PCI_VENDOR_ID_HYGON;
117         else
118                 return -ENODEV;
119
120         pcidev = pci_get_device(pci_vendor,
121                         PCI_DEVICE_ID_AMD_KERNCZ_SMBUS, NULL);
122
123         if (!pcidev) {
124                 if (!boot_cpu_has(X86_FEATURE_PROC_FEEDBACK))
125                         return -ENODEV;
126         }
127
128         if (rdmsrl_safe(MSR_AMD64_FREQ_SENSITIVITY_ACTUAL, &val))
129                 return -ENODEV;
130
131         if (!(val >> CLASS_CODE_SHIFT))
132                 return -ENODEV;
133
134         od_register_powersave_bias_handler(amd_powersave_bias_target,
135                         POWERSAVE_BIAS_DEF);
136         return 0;
137 }
138 late_initcall(amd_freq_sensitivity_init);
139
140 static void __exit amd_freq_sensitivity_exit(void)
141 {
142         od_unregister_powersave_bias_handler();
143 }
144 module_exit(amd_freq_sensitivity_exit);
145
146 static const struct x86_cpu_id amd_freq_sensitivity_ids[] = {
147         X86_FEATURE_MATCH(X86_FEATURE_PROC_FEEDBACK),
148         {}
149 };
150 MODULE_DEVICE_TABLE(x86cpu, amd_freq_sensitivity_ids);
151
152 MODULE_AUTHOR("Jacob Shin <jacob.shin@amd.com>");
153 MODULE_DESCRIPTION("AMD frequency sensitivity feedback powersave bias for "
154                 "the ondemand governor.");
155 MODULE_LICENSE("GPL");