drivers/thermal/intel/intel_tcc_cooling.c

   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/module.h>
  11 #include <linux/thermal.h>
  12 #include <asm/cpu_device_id.h>
  13
  14 #define TCC_SHIFT 24
  15 #define TCC_MASK        (0x3fULL<<24)
  16 #define TCC_PROGRAMMABLE        BIT(30)
  17
  18 static struct thermal_cooling_device *tcc_cdev;
  19
  20 static int tcc_get_max_state(struct thermal_cooling_device *cdev, unsigned long
  21                              *state)
  22 {
  23         *state = TCC_MASK >> TCC_SHIFT;
  24         return 0;
  25 }
  26
  27 static int tcc_offset_update(int tcc)
  28 {
  29         u64 val;
  30         int err;
  31
  32         err = rdmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
  33         if (err)
  34                 return err;
  35
  36         val &= ~TCC_MASK;
  37         val |= tcc << TCC_SHIFT;
  38
  39         err = wrmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, val);
  40         if (err)
  41                 return err;
  42
  43         return 0;
  44 }
  45
  46 static int tcc_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
  47                              *state)
  48 {
  49         u64 val;
  50         int err;
  51
  52         err = rdmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
  53         if (err)
  54                 return err;
  55
  56         *state = (val & TCC_MASK) >> TCC_SHIFT;
  57         return 0;
  58 }
  59
  60 static int tcc_set_cur_state(struct thermal_cooling_device *cdev, unsigned long
  61                              state)
  62 {
  63         return tcc_offset_update(state);
  64 }
  65
  66 static const struct thermal_cooling_device_ops tcc_cooling_ops = {
  67         .get_max_state = tcc_get_max_state,
  68         .get_cur_state = tcc_get_cur_state,
  69         .set_cur_state = tcc_set_cur_state,
  70 };
  71
  72 static const struct x86_cpu_id tcc_ids[] __initconst = {
  73         X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE, NULL),
  74         X86_MATCH_INTEL_FAM6_MODEL(SKYLAKE_L, NULL),
  75         X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE, NULL),
  76         X86_MATCH_INTEL_FAM6_MODEL(KABYLAKE_L, NULL),
  77         X86_MATCH_INTEL_FAM6_MODEL(ICELAKE, NULL),
  78         X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L, NULL),
  79         X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE, NULL),
  80         X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE_L, NULL),
  81         X86_MATCH_INTEL_FAM6_MODEL(COMETLAKE, NULL),
  82         X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE, NULL),
  83         X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE_L, NULL),
  84         {}
  85 };
  86
  87 MODULE_DEVICE_TABLE(x86cpu, tcc_ids);
  88
  89 static int __init tcc_cooling_init(void)
  90 {
  91         int ret;
  92         u64 val;
  93         const struct x86_cpu_id *id;
  94
  95         int err;
  96
  97         id = x86_match_cpu(tcc_ids);
  98         if (!id)
  99                 return -ENODEV;
 100
 101         err = rdmsrl_safe(MSR_PLATFORM_INFO, &val);
 102         if (err)
 103                 return err;
 104
 105         if (!(val & TCC_PROGRAMMABLE))
 106                 return -ENODEV;
 107
 108         pr_info("Programmable TCC Offset detected\n");
 109
 110         tcc_cdev =
 111             thermal_cooling_device_register("TCC Offset", NULL,
 112                                             &tcc_cooling_ops);
 113         if (IS_ERR(tcc_cdev)) {
 114                 ret = PTR_ERR(tcc_cdev);
 115                 return ret;
 116         }
 117         return 0;
 118 }
 119
 120 module_init(tcc_cooling_init)
 121
 122 static void __exit tcc_cooling_exit(void)
 123 {
 124         thermal_cooling_device_unregister(tcc_cdev);
 125 }
 126
 127 module_exit(tcc_cooling_exit)
 128
 129 MODULE_DESCRIPTION("TCC offset cooling device Driver");
 130 MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>");
 131 MODULE_LICENSE("GPL v2");