linux/drivers/thermal/intel/intel_tcc.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * intel_tcc.c - Library for Intel TCC (thermal control circuitry) MSR access
 * Copyright (c) 2022, Intel Corporation.
 */

#include <linux/errno.h>
#include <linux/intel_tcc.h>
#include <asm/cpu_device_id.h>
#include <asm/intel-family.h>
#include <asm/msr.h>

/**
 * struct temp_masks - Bitmasks for temperature readings
 * @tcc_offset:			TCC offset in MSR_TEMPERATURE_TARGET
 * @digital_readout:		Digital readout in MSR_IA32_THERM_STATUS
 * @pkg_digital_readout:	Digital readout in MSR_IA32_PACKAGE_THERM_STATUS
 *
 * Bitmasks to extract the fields of the MSR_TEMPERATURE and IA32_[PACKAGE]_
 * THERM_STATUS registers for different processor models.
 *
 * The bitmask of TjMax is not included in this structure. It is always 0xff.
 */
struct temp_masks { … };

#define TCC_MODEL_TEMP_MASKS(model, _tcc_offset, _digital_readout,	\
			     _pkg_digital_readout) …

TCC_MODEL_TEMP_MASKS(nehalem, 0, 0x7f, 0x7f);
TCC_MODEL_TEMP_MASKS(haswell_x, 0xf, 0x7f, 0x7f);
TCC_MODEL_TEMP_MASKS(broadwell, 0x3f, 0x7f, 0x7f);
TCC_MODEL_TEMP_MASKS(goldmont, 0x7f, 0x7f, 0x7f);
TCC_MODEL_TEMP_MASKS(tigerlake, 0x3f, 0xff, 0xff);
TCC_MODEL_TEMP_MASKS(sapphirerapids, 0x3f, 0x7f, 0xff);

/* Use these masks for processors not included in @tcc_cpu_ids. */
static struct temp_masks intel_tcc_temp_masks __ro_after_init = …;

static const struct x86_cpu_id intel_tcc_cpu_ids[] __initconst = …;

static int __init intel_tcc_init(void)
{ … }
/*
 * Use subsys_initcall to ensure temperature bitmasks are initialized before
 * the drivers that use this library.
 */
subsys_initcall(intel_tcc_init);

/**
 * intel_tcc_get_offset_mask() - Returns the bitmask to read TCC offset
 *
 * Get the model-specific bitmask to extract TCC_OFFSET from the MSR
 * TEMPERATURE_TARGET register. If the mask is 0, it means the processor does
 * not support TCC offset.
 *
 * Return: The model-specific bitmask for TCC offset.
 */
u32 intel_tcc_get_offset_mask(void)
{ … }
EXPORT_SYMBOL_NS(…);

/**
 * get_temp_mask() - Returns the model-specific bitmask for temperature
 *
 * @pkg: true: Package Thermal Sensor. false: Core Thermal Sensor.
 *
 * Get the model-specific bitmask to extract the temperature reading from the
 * MSR_IA32_[PACKAGE]_THERM_STATUS register.
 *
 * Callers must check if the thermal status registers are supported.
 *
 * Return: The model-specific bitmask for temperature reading
 */
static u32 get_temp_mask(bool pkg)
{ … }

/**
 * intel_tcc_get_tjmax() - returns the default TCC activation Temperature
 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
 *
 * Get the TjMax value, which is the default thermal throttling or TCC
 * activation temperature in degrees C.
 *
 * Return: Tjmax value in degrees C on success, negative error code otherwise.
 */
int intel_tcc_get_tjmax(int cpu)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * intel_tcc_get_offset() - returns the TCC Offset value to Tjmax
 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
 *
 * Get the TCC offset value to Tjmax. The effective thermal throttling or TCC
 * activation temperature equals "Tjmax" - "TCC Offset", in degrees C.
 *
 * Return: Tcc offset value in degrees C on success, negative error code otherwise.
 */
int intel_tcc_get_offset(int cpu)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * intel_tcc_set_offset() - set the TCC offset value to Tjmax
 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
 * @offset: TCC offset value in degree C
 *
 * Set the TCC Offset value to Tjmax. The effective thermal throttling or TCC
 * activation temperature equals "Tjmax" - "TCC Offset", in degree C.
 *
 * Return: On success returns 0, negative error code otherwise.
 */

int intel_tcc_set_offset(int cpu, int offset)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

/**
 * intel_tcc_get_temp() - returns the current temperature
 * @cpu: cpu that the MSR should be run on, nagative value means any cpu.
 * @temp: pointer to the memory for saving cpu temperature.
 * @pkg: true: Package Thermal Sensor. false: Core Thermal Sensor.
 *
 * Get the current temperature returned by the CPU core/package level
 * thermal sensor, in degrees C.
 *
 * Return: 0 on success, negative error code otherwise.
 */
int intel_tcc_get_temp(int cpu, int *temp, bool pkg)
{ … }
EXPORT_SYMBOL_NS_GPL(…);