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/**
* @file medlock.h
*
* @brief Provides the device lock class.
* @note Copyright (C) 2006 Meilhaus Electronic GmbH (support@meilhaus.de)
* @author Guenter Gebhardt
*/
#ifndef _MEDLOCK_H_
#define _MEDLOCK_H_
#include <linux/spinlock.h>
#ifdef __KERNEL__
/**
* @brief The device lock class.
*/
typedef struct me_dlock {
struct file *filep; /**< Pointer to file structure holding the device. */
int count; /**< Number of tasks which are inside the device. */
spinlock_t spin_lock; /**< Spin lock protecting the attributes from concurrent access. */
} me_dlock_t;
/**
* @brief Tries to enter a device.
*
* @param dlock The device lock instance.
* @param filep The file structure identifying the calling process.
*
* @return 0 on success.
*/
int me_dlock_enter(struct me_dlock *dlock, struct file *filep);
/**
* @brief Exits a device.
*
* @param dlock The device lock instance.
* @param filep The file structure identifying the calling process.
*
* @return 0 on success.
*/
int me_dlock_exit(struct me_dlock *dlock, struct file *filep);
/**
* @brief Tries to perform a locking action on a device.
*
* @param dlock The device lock instance.
* @param filep The file structure identifying the calling process.
* @param The action to be done.
* @param flags Flags from user space.
* @param slist The subdevice list of the device.
*
* @return 0 on success.
*/
int me_dlock_lock(struct me_dlock *dlock,
struct file *filep, int lock, int flags, me_slist_t * slist);
/**
* @brief Initializes a lock structure.
*
* @param dlock The lock structure to initialize.
* @return 0 on success.
*/
int me_dlock_init(me_dlock_t * dlock);
/**
* @brief Deinitializes a lock structure.
*
* @param dlock The lock structure to deinitialize.
* @return 0 on success.
*/
void me_dlock_deinit(me_dlock_t * dlock);
#endif
#endif
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