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/**
* @file meslock.h
*
* @brief Provides the subdevice lock class.
* @note Copyright (C) 2006 Meilhaus Electronic GmbH (support@meilhaus.de)
* @author Guenter Gebhardt
*/
#ifndef _MESLOCK_H_
#define _MESLOCK_H_
#include <linux/spinlock.h>
#ifdef __KERNEL__
/**
* @brief The subdevice lock class.
*/
typedef struct me_slock {
struct file *filep; /**< Pointer to file structure holding the subdevice. */
int count; /**< Number of tasks which are inside the subdevice. */
spinlock_t spin_lock; /**< Spin lock protecting the attributes from concurrent access. */
} me_slock_t;
/**
* @brief Tries to enter a subdevice.
*
* @param slock The subdevice lock instance.
* @param filep The file structure identifying the calling process.
*
* @return 0 on success.
*/
int me_slock_enter(struct me_slock *slock, struct file *filep);
/**
* @brief Exits a subdevice.
*
* @param slock The subdevice lock instance.
* @param filep The file structure identifying the calling process.
*
* @return 0 on success.
*/
int me_slock_exit(struct me_slock *slock, struct file *filep);
/**
* @brief Tries to perform a locking action on a subdevice.
*
* @param slock The subdevice lock instance.
* @param filep The file structure identifying the calling process.
* @param The action to be done.
*
* @return 0 on success.
*/
int me_slock_lock(struct me_slock *slock, struct file *filep, int lock);
/**
* @brief Initializes a lock structure.
*
* @param slock The lock structure to initialize.
* @return 0 on success.
*/
int me_slock_init(me_slock_t * slock);
/**
* @brief Deinitializes a lock structure.
*
* @param slock The lock structure to deinitialize.
* @return 0 on success.
*/
void me_slock_deinit(me_slock_t * slock);
#endif
#endif
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