blob: efce22b8ae608883b5d519d00392fb4df45ef3aa [file] [log] [blame]
/*
* Copyright (c) 2020 Tobias Svehagen
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_
#define ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_
#include <zephyr.h>
#include <sys/fdtable.h>
#include <sys/types.h>
#include <fcntl.h>
#ifdef __cplusplus
extern "C" {
#endif
#define EFD_IN_USE 0x1
#define EFD_SEMAPHORE 0x2
#define EFD_NONBLOCK O_NONBLOCK
#define EFD_FLAGS_SET (EFD_SEMAPHORE | EFD_NONBLOCK)
typedef uint64_t eventfd_t;
/**
* @brief Create a file descriptor for event notification
*
* The returned file descriptor can be used with POSIX read/write calls or
* with the eventfd_read/eventfd_write functions.
*
* It also supports polling and by including an eventfd in a call to poll,
* it is possible to signal and wake the polling thread by simply writing to
* the eventfd.
*
* When using read() and write() on an eventfd, the size must always be at
* least 8 bytes or the operation will fail with EINVAL.
*
* @return New eventfd file descriptor on success, -1 on error
*/
int eventfd(unsigned int initval, int flags);
/**
* @brief Read from an eventfd
*
* If call is successful, the value parameter will have the value 1
*
* @param fd File descriptor
* @param value Pointer for storing the read value
*
* @return 0 on success, -1 on error
*/
static inline int eventfd_read(int fd, eventfd_t *value)
{
const struct fd_op_vtable *efd_vtable;
struct k_mutex *lock;
ssize_t ret;
void *obj;
obj = z_get_fd_obj_and_vtable(fd, &efd_vtable, &lock);
(void)k_mutex_lock(lock, K_FOREVER);
ret = efd_vtable->read(obj, value, sizeof(*value));
k_mutex_unlock(lock);
return ret == sizeof(eventfd_t) ? 0 : -1;
}
/**
* @brief Write to an eventfd
*
* @param fd File descriptor
* @param value Value to write
*
* @return 0 on success, -1 on error
*/
static inline int eventfd_write(int fd, eventfd_t value)
{
const struct fd_op_vtable *efd_vtable;
struct k_mutex *lock;
ssize_t ret;
void *obj;
obj = z_get_fd_obj_and_vtable(fd, &efd_vtable, &lock);
(void)k_mutex_lock(lock, K_FOREVER);
ret = efd_vtable->write(obj, &value, sizeof(value));
k_mutex_unlock(lock);
return ret == sizeof(eventfd_t) ? 0 : -1;
}
#ifdef __cplusplus
}
#endif
#endif /* ZEPHYR_INCLUDE_POSIX_SYS_EVENTFD_H_ */