1 /* 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 #define ZVFS_EFD_SEMAPHORE 2 19 #define ZVFS_EFD_NONBLOCK 0x4000 20 21 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 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 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 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_ */ 67
