hwspinlock.h
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/* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */
/*
* Copyright (C) 2018, STMicroelectronics - All Rights Reserved
*/
#ifndef _HWSPINLOCK_H_
#define _HWSPINLOCK_H_
/**
* Implement a hwspinlock uclass.
* Hardware spinlocks are used to perform hardware protection of
* critical sections and synchronisation between multiprocessors.
*/
struct udevice;
/**
* struct hwspinlock - A handle to (allowing control of) a single hardware
* spinlock.
*
* @dev: The device which implements the hardware spinlock.
* @id: The hardware spinlock ID within the provider.
*/
struct hwspinlock {
struct udevice *dev;
unsigned long id;
};
#if CONFIG_IS_ENABLED(DM_HWSPINLOCK)
/**
* hwspinlock_get_by_index - Get a hardware spinlock by integer index
*
* This looks up and request a hardware spinlock. The index is relative to the
* client device; each device is assumed to have n hardware spinlock associated
* with it somehow, and this function finds and requests one of them.
*
* @dev: The client device.
* @index: The index of the hardware spinlock to request, within the
* client's list of hardware spinlock.
* @hws: A pointer to a hardware spinlock struct to initialize.
* @return 0 if OK, or a negative error code.
*/
int hwspinlock_get_by_index(struct udevice *dev,
int index, struct hwspinlock *hws);
/**
* Lock the hardware spinlock
*
* @hws: A hardware spinlock struct that previously requested by
* hwspinlock_get_by_index
* @timeout: Timeout value in msecs
* @return: 0 if OK, -ETIMEDOUT if timeout, -ve on other errors
*/
int hwspinlock_lock_timeout(struct hwspinlock *hws, unsigned int timeout);
/**
* Unlock the hardware spinlock
*
* @hws: A hardware spinlock struct that previously requested by
* hwspinlock_get_by_index
* @return: 0 if OK, -ve on error
*/
int hwspinlock_unlock(struct hwspinlock *hws);
#else
static inline int hwspinlock_get_by_index(struct udevice *dev,
int index,
struct hwspinlock *hws)
{
return -ENOSYS;
}
static inline int hwspinlock_lock_timeout(struct hwspinlock *hws,
int timeout)
{
return -ENOSYS;
}
static inline int hwspinlock_unlock(struct hwspinlock *hws)
{
return -ENOSYS;
}
#endif /* CONFIG_DM_HWSPINLOCK */
struct ofnode_phandle_args;
/**
* struct hwspinlock_ops - Driver model hwspinlock operations
*
* The uclass interface is implemented by all hwspinlock devices which use
* driver model.
*/
struct hwspinlock_ops {
/**
* of_xlate - Translate a client's device-tree (OF) hardware specifier.
*
* The hardware core calls this function as the first step in
* implementing a client's hwspinlock_get_by_*() call.
*
* @hws: The hardware spinlock struct to hold the translation
* result.
* @args: The hardware spinlock specifier values from device tree.
* @return 0 if OK, or a negative error code.
*/
int (*of_xlate)(struct hwspinlock *hws,
struct ofnode_phandle_args *args);
/**
* Lock the hardware spinlock
*
* @dev: hwspinlock Device
* @index: index of the lock to be used
* @return 0 if OK, -ve on error
*/
int (*lock)(struct udevice *dev, int index);
/**
* Unlock the hardware spinlock
*
* @dev: hwspinlock Device
* @index: index of the lock to be unlocked
* @return 0 if OK, -ve on error
*/
int (*unlock)(struct udevice *dev, int index);
/**
* Relax - optional
* Platform-specific relax method, called by hwspinlock core
* while spinning on a lock, between two successive call to
* lock
*
* @dev: hwspinlock Device
*/
void (*relax)(struct udevice *dev);
};
#endif /* _HWSPINLOCK_H_ */