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_ */