1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * intel_tcc.c - Library for Intel TCC (thermal control circuitry) MSR access
4 * Copyright (c) 2022, Intel Corporation.
5 */
6
7 #include <linux/errno.h>
8 #include <linux/intel_tcc.h>
9 #include <asm/msr.h>
10
11 /**
12 * intel_tcc_get_tjmax() - returns the default TCC activation Temperature
13 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
14 *
15 * Get the TjMax value, which is the default thermal throttling or TCC
16 * activation temperature in degrees C.
17 *
18 * Return: Tjmax value in degrees C on success, negative error code otherwise.
19 */
intel_tcc_get_tjmax(int cpu)20 int intel_tcc_get_tjmax(int cpu)
21 {
22 u32 low, high;
23 int val, err;
24
25 if (cpu < 0)
26 err = rdmsr_safe(MSR_IA32_TEMPERATURE_TARGET, &low, &high);
27 else
28 err = rdmsr_safe_on_cpu(cpu, MSR_IA32_TEMPERATURE_TARGET, &low, &high);
29 if (err)
30 return err;
31
32 val = (low >> 16) & 0xff;
33
34 return val ? val : -ENODATA;
35 }
36 EXPORT_SYMBOL_NS_GPL(intel_tcc_get_tjmax, INTEL_TCC);
37
38 /**
39 * intel_tcc_get_offset() - returns the TCC Offset value to Tjmax
40 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
41 *
42 * Get the TCC offset value to Tjmax. The effective thermal throttling or TCC
43 * activation temperature equals "Tjmax" - "TCC Offset", in degrees C.
44 *
45 * Return: Tcc offset value in degrees C on success, negative error code otherwise.
46 */
intel_tcc_get_offset(int cpu)47 int intel_tcc_get_offset(int cpu)
48 {
49 u32 low, high;
50 int err;
51
52 if (cpu < 0)
53 err = rdmsr_safe(MSR_IA32_TEMPERATURE_TARGET, &low, &high);
54 else
55 err = rdmsr_safe_on_cpu(cpu, MSR_IA32_TEMPERATURE_TARGET, &low, &high);
56 if (err)
57 return err;
58
59 return (low >> 24) & 0x3f;
60 }
61 EXPORT_SYMBOL_NS_GPL(intel_tcc_get_offset, INTEL_TCC);
62
63 /**
64 * intel_tcc_set_offset() - set the TCC offset value to Tjmax
65 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
66 * @offset: TCC offset value in degree C
67 *
68 * Set the TCC Offset value to Tjmax. The effective thermal throttling or TCC
69 * activation temperature equals "Tjmax" - "TCC Offset", in degree C.
70 *
71 * Return: On success returns 0, negative error code otherwise.
72 */
73
intel_tcc_set_offset(int cpu,int offset)74 int intel_tcc_set_offset(int cpu, int offset)
75 {
76 u32 low, high;
77 int err;
78
79 if (offset < 0 || offset > 0x3f)
80 return -EINVAL;
81
82 if (cpu < 0)
83 err = rdmsr_safe(MSR_IA32_TEMPERATURE_TARGET, &low, &high);
84 else
85 err = rdmsr_safe_on_cpu(cpu, MSR_IA32_TEMPERATURE_TARGET, &low, &high);
86 if (err)
87 return err;
88
89 /* MSR Locked */
90 if (low & BIT(31))
91 return -EPERM;
92
93 low &= ~(0x3f << 24);
94 low |= offset << 24;
95
96 if (cpu < 0)
97 return wrmsr_safe(MSR_IA32_TEMPERATURE_TARGET, low, high);
98 else
99 return wrmsr_safe_on_cpu(cpu, MSR_IA32_TEMPERATURE_TARGET, low, high);
100 }
101 EXPORT_SYMBOL_NS_GPL(intel_tcc_set_offset, INTEL_TCC);
102
103 /**
104 * intel_tcc_get_temp() - returns the current temperature
105 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
106 * @pkg: true: Package Thermal Sensor. false: Core Thermal Sensor.
107 *
108 * Get the current temperature returned by the CPU core/package level
109 * thermal sensor, in degrees C.
110 *
111 * Return: Temperature in degrees C on success, negative error code otherwise.
112 */
intel_tcc_get_temp(int cpu,bool pkg)113 int intel_tcc_get_temp(int cpu, bool pkg)
114 {
115 u32 low, high;
116 u32 msr = pkg ? MSR_IA32_PACKAGE_THERM_STATUS : MSR_IA32_THERM_STATUS;
117 int tjmax, temp, err;
118
119 tjmax = intel_tcc_get_tjmax(cpu);
120 if (tjmax < 0)
121 return tjmax;
122
123 if (cpu < 0)
124 err = rdmsr_safe(msr, &low, &high);
125 else
126 err = rdmsr_safe_on_cpu(cpu, msr, &low, &high);
127 if (err)
128 return err;
129
130 /* Temperature is beyond the valid thermal sensor range */
131 if (!(low & BIT(31)))
132 return -ENODATA;
133
134 temp = tjmax - ((low >> 16) & 0x7f);
135
136 /* Do not allow negative CPU temperature */
137 return temp >= 0 ? temp : -ENODATA;
138 }
139 EXPORT_SYMBOL_NS_GPL(intel_tcc_get_temp, INTEL_TCC);
140