drivers/staging/meilhaus/meslock.h

   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