David Kiliani | 3fedd14 | 2008-11-01 00:39:12 +0100 | [diff] [blame] | 1 | /** |
| 2 | * @file meslock.h |
| 3 | * |
| 4 | * @brief Provides the subdevice lock class. |
| 5 | * @note Copyright (C) 2006 Meilhaus Electronic GmbH (support@meilhaus.de) |
| 6 | * @author Guenter Gebhardt |
| 7 | */ |
| 8 | |
| 9 | #ifndef _MESLOCK_H_ |
| 10 | #define _MESLOCK_H_ |
| 11 | |
| 12 | #include <linux/spinlock.h> |
| 13 | |
| 14 | #ifdef __KERNEL__ |
| 15 | |
| 16 | /** |
| 17 | * @brief The subdevice lock class. |
| 18 | */ |
| 19 | typedef struct me_slock { |
| 20 | struct file *filep; /**< Pointer to file structure holding the subdevice. */ |
| 21 | int count; /**< Number of tasks which are inside the subdevice. */ |
| 22 | spinlock_t spin_lock; /**< Spin lock protecting the attributes from concurrent access. */ |
| 23 | } me_slock_t; |
| 24 | |
| 25 | /** |
| 26 | * @brief Tries to enter a subdevice. |
| 27 | * |
| 28 | * @param slock The subdevice lock instance. |
| 29 | * @param filep The file structure identifying the calling process. |
| 30 | * |
| 31 | * @return 0 on success. |
| 32 | */ |
| 33 | int me_slock_enter(struct me_slock *slock, struct file *filep); |
| 34 | |
| 35 | /** |
| 36 | * @brief Exits a subdevice. |
| 37 | * |
| 38 | * @param slock The subdevice lock instance. |
| 39 | * @param filep The file structure identifying the calling process. |
| 40 | * |
| 41 | * @return 0 on success. |
| 42 | */ |
| 43 | int me_slock_exit(struct me_slock *slock, struct file *filep); |
| 44 | |
| 45 | /** |
| 46 | * @brief Tries to perform a locking action on a subdevice. |
| 47 | * |
| 48 | * @param slock The subdevice lock instance. |
| 49 | * @param filep The file structure identifying the calling process. |
| 50 | * @param The action to be done. |
| 51 | * |
| 52 | * @return 0 on success. |
| 53 | */ |
| 54 | int me_slock_lock(struct me_slock *slock, struct file *filep, int lock); |
| 55 | |
| 56 | /** |
| 57 | * @brief Initializes a lock structure. |
| 58 | * |
| 59 | * @param slock The lock structure to initialize. |
| 60 | * @return 0 on success. |
| 61 | */ |
| 62 | int me_slock_init(me_slock_t * slock); |
| 63 | |
| 64 | /** |
| 65 | * @brief Deinitializes a lock structure. |
| 66 | * |
| 67 | * @param slock The lock structure to deinitialize. |
| 68 | * @return 0 on success. |
| 69 | */ |
| 70 | void me_slock_deinit(me_slock_t * slock); |
| 71 | |
| 72 | #endif |
| 73 | #endif |