1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * cooling device driver that activates the processor throttling by
4 * programming the TCC Offset register.
5 * Copyright (c) 2021, Intel Corporation.
6 */
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9 #include <linux/device.h>
10 #include <linux/intel_tcc.h>
11 #include <linux/module.h>
12 #include <linux/thermal.h>
13 #include <asm/cpu_device_id.h>
14
15 #define TCC_PROGRAMMABLE BIT(30)
16 #define TCC_LOCKED BIT(31)
17
18 static struct thermal_cooling_device *tcc_cdev;
19
tcc_get_max_state(struct thermal_cooling_device * cdev,unsigned long * state)20 static int tcc_get_max_state(struct thermal_cooling_device *cdev, unsigned long
21 *state)
22 {
23 *state = 0x3f;
24 return 0;
25 }
26
tcc_get_cur_state(struct thermal_cooling_device * cdev,unsigned long * state)27 static int tcc_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
28 *state)
29 {
30 int offset = intel_tcc_get_offset(-1);
31
32 if (offset < 0)
33 return offset;
34
35 *state = offset;
36 return 0;
37 }
38
tcc_set_cur_state(struct thermal_cooling_device * cdev,unsigned long state)39 static int tcc_set_cur_state(struct thermal_cooling_device *cdev, unsigned long
40 state)
41 {
42 return intel_tcc_set_offset(-1, (int)state);
43 }
44
45 static const struct thermal_cooling_device_ops tcc_cooling_ops = {
46 .get_max_state = tcc_get_max_state,
47 .get_cur_state = tcc_get_cur_state,
48 .set_cur_state = tcc_set_cur_state,
49 };
50
51 static const struct x86_cpu_id tcc_ids[] __initconst = {
52 X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE, NULL),
53 X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_L, NULL),
54 X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE, NULL),
55 X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L, NULL),
56 X86_MATCH_INTEL_FAM6_MODEL(ICELAKE, NULL),
57 X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L, NULL),
58 X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE, NULL),
59 X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE_L, NULL),
60 X86_MATCH_INTEL_FAM6_MODEL(COMETLAKE, NULL),
61 X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE, NULL),
62 X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE_L, NULL),
63 X86_MATCH_INTEL_FAM6_MODEL(ATOM_GRACEMONT, NULL),
64 X86_MATCH_INTEL_FAM6_MODEL(RAPTORLAKE, NULL),
65 X86_MATCH_INTEL_FAM6_MODEL(RAPTORLAKE_P, NULL),
66 X86_MATCH_INTEL_FAM6_MODEL(RAPTORLAKE_S, NULL),
67 {}
68 };
69
70 MODULE_DEVICE_TABLE(x86cpu, tcc_ids);
71
tcc_cooling_init(void)72 static int __init tcc_cooling_init(void)
73 {
74 int ret;
75 u64 val;
76 const struct x86_cpu_id *id;
77
78 int err;
79
80 id = x86_match_cpu(tcc_ids);
81 if (!id)
82 return -ENODEV;
83
84 err = rdmsrl_safe(MSR_PLATFORM_INFO, &val);
85 if (err)
86 return err;
87
88 if (!(val & TCC_PROGRAMMABLE))
89 return -ENODEV;
90
91 err = rdmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
92 if (err)
93 return err;
94
95 if (val & TCC_LOCKED) {
96 pr_info("TCC Offset locked\n");
97 return -ENODEV;
98 }
99
100 pr_info("Programmable TCC Offset detected\n");
101
102 tcc_cdev =
103 thermal_cooling_device_register("TCC Offset", NULL,
104 &tcc_cooling_ops);
105 if (IS_ERR(tcc_cdev)) {
106 ret = PTR_ERR(tcc_cdev);
107 return ret;
108 }
109 return 0;
110 }
111
module_init(tcc_cooling_init)112 module_init(tcc_cooling_init)
113
114 static void __exit tcc_cooling_exit(void)
115 {
116 thermal_cooling_device_unregister(tcc_cdev);
117 }
118
119 module_exit(tcc_cooling_exit)
120
121 MODULE_IMPORT_NS(INTEL_TCC);
122 MODULE_DESCRIPTION("TCC offset cooling device Driver");
123 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
124 MODULE_LICENSE("GPL v2");
125