tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#include <asm/msr.h>
15
16#define TCC_PROGRAMMABLE BIT(30)
17#define TCC_LOCKED BIT(31)
18
19static struct thermal_cooling_device *tcc_cdev;
20
21static int tcc_get_max_state(struct thermal_cooling_device *cdev, unsigned long
22 *state)
23{
24 *state = intel_tcc_get_offset_mask();
25 return 0;
26}
27
28static int tcc_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
29 *state)
30{
31 int offset = intel_tcc_get_offset(-1);
32
33 if (offset < 0)
34 return offset;
35
36 *state = offset;
37 return 0;
38}
39
40static int tcc_set_cur_state(struct thermal_cooling_device *cdev, unsigned long
41 state)
42{
43 return intel_tcc_set_offset(-1, (int)state);
44}
45
46static const struct thermal_cooling_device_ops tcc_cooling_ops = {
47 .get_max_state = tcc_get_max_state,
48 .get_cur_state = tcc_get_cur_state,
49 .set_cur_state = tcc_set_cur_state,
50};
51
52static const struct x86_cpu_id tcc_ids[] __initconst = {
53 X86_MATCH_VFM(INTEL_SKYLAKE, NULL),
54 X86_MATCH_VFM(INTEL_SKYLAKE_L, NULL),
55 X86_MATCH_VFM(INTEL_KABYLAKE, NULL),
56 X86_MATCH_VFM(INTEL_KABYLAKE_L, NULL),
57 X86_MATCH_VFM(INTEL_ICELAKE, NULL),
58 X86_MATCH_VFM(INTEL_ICELAKE_L, NULL),
59 X86_MATCH_VFM(INTEL_TIGERLAKE, NULL),
60 X86_MATCH_VFM(INTEL_TIGERLAKE_L, NULL),
61 X86_MATCH_VFM(INTEL_COMETLAKE, NULL),
62 X86_MATCH_VFM(INTEL_ALDERLAKE, NULL),
63 X86_MATCH_VFM(INTEL_ALDERLAKE_L, NULL),
64 X86_MATCH_VFM(INTEL_ATOM_GRACEMONT, NULL),
65 X86_MATCH_VFM(INTEL_RAPTORLAKE, NULL),
66 X86_MATCH_VFM(INTEL_RAPTORLAKE_P, NULL),
67 X86_MATCH_VFM(INTEL_RAPTORLAKE_S, NULL),
68 {}
69};
70
71MODULE_DEVICE_TABLE(x86cpu, tcc_ids);
72
73static int __init tcc_cooling_init(void)
74{
75 int ret;
76 u64 val;
77 const struct x86_cpu_id *id;
78
79 int err;
80
81 id = x86_match_cpu(tcc_ids);
82 if (!id)
83 return -ENODEV;
84
85 err = rdmsrq_safe(MSR_PLATFORM_INFO, &val);
86 if (err)
87 return err;
88
89 if (!(val & TCC_PROGRAMMABLE))
90 return -ENODEV;
91
92 err = rdmsrq_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
93 if (err)
94 return err;
95
96 if (val & TCC_LOCKED) {
97 pr_info("TCC Offset locked\n");
98 return -ENODEV;
99 }
100
101 pr_info("Programmable TCC Offset detected\n");
102
103 tcc_cdev =
104 thermal_cooling_device_register("TCC Offset", NULL,
105 &tcc_cooling_ops);
106 if (IS_ERR(tcc_cdev)) {
107 ret = PTR_ERR(tcc_cdev);
108 return ret;
109 }
110 return 0;
111}
112
113module_init(tcc_cooling_init)
114
115static void __exit tcc_cooling_exit(void)
116{
117 thermal_cooling_device_unregister(tcc_cdev);
118}
119
120module_exit(tcc_cooling_exit)
121
122MODULE_IMPORT_NS("INTEL_TCC");
123MODULE_DESCRIPTION("TCC offset cooling device Driver");
124MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
125MODULE_LICENSE("GPL v2");