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