Line data    Source code

       1            0 : /*
       2              :  * Copyright (c) 2020 Tobias Svehagen
       3              :  *
       4              :  * SPDX-License-Identifier: Apache-2.0
       5              :  */
       6              : 
       7              : #ifndef ZEPHYR_INCLUDE_ZEPHYR_ZVFS_EVENTFD_H_
       8              : #define ZEPHYR_INCLUDE_ZEPHYR_ZVFS_EVENTFD_H_
       9              : 
      10              : #include <stdint.h>
      11              : 
      12              : #include <zephyr/kernel.h>
      13              : 
      14              : #ifdef __cplusplus
      15              : extern "C" {
      16              : #endif
      17              : 
      18            0 : #define ZVFS_EFD_SEMAPHORE 2
      19            0 : #define ZVFS_EFD_NONBLOCK 0x4000
      20              : 
      21            0 : typedef uint64_t zvfs_eventfd_t;
      22              : 
      23              : /**
      24              :  * @brief Create a file descriptor for ZVFS event notification
      25              :  *
      26              :  * The returned file descriptor can be used with POSIX read/write calls or
      27              :  * with the @ref zvfs_eventfd_read or @ref zvfs_eventfd_write functions.
      28              :  *
      29              :  * It also supports polling and by including an eventfd in a call to poll,
      30              :  * it is possible to signal and wake the polling thread by simply writing to
      31              :  * the eventfd.
      32              :  *
      33              :  * When using read() and write() on a ZVFS eventfd, the size must always be at
      34              :  * least 8 bytes or the operation will fail with EINVAL.
      35              :  *
      36              :  * @return New ZVFS eventfd file descriptor on success, -1 on error
      37              :  */
      38            1 : int zvfs_eventfd(unsigned int initval, int flags);
      39              : 
      40              : /**
      41              :  * @brief Read from a ZVFS eventfd
      42              :  *
      43              :  * If call is successful, the value parameter will have the value 1
      44              :  *
      45              :  * @param fd File descriptor
      46              :  * @param value Pointer for storing the read value
      47              :  *
      48              :  * @return 0 on success, -1 on error
      49              :  */
      50            1 : int zvfs_eventfd_read(int fd, zvfs_eventfd_t *value);
      51              : 
      52              : /**
      53              :  * @brief Write to a ZVFS eventfd
      54              :  *
      55              :  * @param fd File descriptor
      56              :  * @param value Value to write
      57              :  *
      58              :  * @return 0 on success, -1 on error
      59              :  */
      60            1 : int zvfs_eventfd_write(int fd, zvfs_eventfd_t value);
      61              : 
      62              : #ifdef __cplusplus
      63              : }
      64              : #endif
      65              : 
      66              : #endif /* ZEPHYR_INCLUDE_ZEPHYR_ZVFS_EVENTFD_H_ */