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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Thermal management support for GCIP devices.
*
* Copyright (C) 2023 Google LLC
*/
#ifndef __GCIP_THERMAL_H__
#define __GCIP_THERMAL_H__
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/notifier.h>
#include <linux/thermal.h>
#define GCIP_THERMAL_TABLE_SIZE_NAME "gcip-dvfs-table-size"
#define GCIP_THERMAL_TABLE_NAME "gcip-dvfs-table"
#define GCIP_THERMAL_MAX_NUM_STATES 10
enum gcip_thermal_voter {
GCIP_THERMAL_COOLING_DEVICE,
GCIP_THERMAL_SYSFS,
GCIP_THERMAL_NOTIFIER_BLOCK,
/* Keeps as the last entry for the total number of voters. */
GCIP_THERMAL_MAX_NUM_VOTERS,
};
struct gcip_thermal {
struct device *dev;
struct thermal_cooling_device *cdev;
struct notifier_block nb;
struct dentry *dentry;
struct gcip_pm *pm;
/*
* Lock to protect the struct members listed below.
*
* Note that since the request of thermal state adjusting might happen during power state
* transitions (i.e., another thread calling gcip_thermal_restore_on_powering() with pm lock
* held), one must either use the non-blocking gcip_pm_get_if_powered() or make sure there
* won't be any new power transition after holding this thermal lock to prevent deadlock.
*/
struct mutex lock;
unsigned long num_states;
unsigned long state;
unsigned long vote[GCIP_THERMAL_MAX_NUM_VOTERS];
bool device_suspended;
bool enabled;
/* Private data. See struct gcip_thermal_args.*/
void *data;
/* Callbacks. See struct gcip_thermal_args. */
int (*get_rate)(void *data, unsigned long *rate);
int (*set_rate)(void *data, unsigned long rate);
int (*control)(void *data, bool enable);
};
/* Arguments for devm_gcip_thermal_create. */
struct gcip_thermal_args {
/* Device struct of GCIP device. */
struct device *dev;
/* GCIP power management. */
struct gcip_pm *pm;
/* Top-level debugfs directory for the device. */
struct dentry *dentry;
/* Name of the thermal cooling-device node in device tree. */
const char *node_name;
/* Thermal cooling device type for thermal_of_cooling_device_register() . */
const char *type;
/* Private data for callbacks listed below. */
void *data;
/*
* Callbacks listed below are called only if the device is powered and with the guarantee
* that there won't be any new power transition during the call (i.e., after
* gcip_pm_get_if_powered() succeeds or during the power up triggered by gcip_pm_get())
* to prevent deadlock since they are called with thermal lock held. See the note about
* thermal lock in struct gcip_thermal.
*/
/* Callback to get the device clock rate. */
int (*get_rate)(void *data, unsigned long *rate);
/*
* Callback to set the device clock rate.
* Might be called with pm lock held in gcip_thermal_restore_on_powering().
*/
int (*set_rate)(void *data, unsigned long rate);
/*
* Callback to enable/disable the thermal control.
* Might be called with pm lock held in gcip_thermal_restore_on_powering().
*/
int (*control)(void *data, bool enable);
};
/* Gets the notifier_block struct for thermal throttling requests. */
struct notifier_block *gcip_thermal_get_notifier_block(struct gcip_thermal *thermal);
/* Allocates and initializes GCIP thermal struct. */
struct gcip_thermal *gcip_thermal_create(const struct gcip_thermal_args *args);
/* Destroys and frees GCIP thermal struct. */
void gcip_thermal_destroy(struct gcip_thermal *thermal);
/* Suspends the device due to thermal request. */
int gcip_thermal_suspend_device(struct gcip_thermal *thermal);
/* Resumes the device and restores previous thermal state. */
int gcip_thermal_resume_device(struct gcip_thermal *thermal);
/*
* Checks whether the device is suspended by thermal.
* Note that it's checked without thermal lock and state might change subsequently.
*/
bool gcip_thermal_is_device_suspended(struct gcip_thermal *thermal);
/*
* Restores the previous thermal state.
*
* This function is designed to restore the thermal state during power management calls and thus it
* assumes the caller holds the pm lock.
*/
int gcip_thermal_restore_on_powering(struct gcip_thermal *thermal);
#endif /* __GCIP_THERMAL_H__ */
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