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lib: posix: nanosleep

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This change adds support for nanosleep(2) documented at
https://pubs.opengroup.org/onlinepubs/9699919799/functions/nanosleep.html

N.B: Currently, this provides no better resolution than
k_busy_wait()

Fixes #25554

Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
This commit is contained in:
Christopher Friedt 2020-05-23 06:09:28 -04:00 committed by Carles Cufí
parent 8c29aa9881
commit 8bcf005084
3 changed files with 65 additions and 0 deletions
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1
include/posix/time.h
View file

@ -91,6 +91,7 @@ int timer_delete(timer_t timerid);
int timer_gettime(timer_t timerid, struct itimerspec *its);
int timer_settime(timer_t timerid, int flags, const struct itimerspec *value,
struct itimerspec *ovalue);
int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
#ifdef __cplusplus
}

4
lib/posix/CMakeLists.txt
View file

@ -24,6 +24,10 @@ zephyr_library_sources_ifdef(CONFIG_POSIX_MQUEUE mqueue.c)
zephyr_library_sources_ifdef(CONFIG_POSIX_FS fs.c)
zephyr_library_sources_ifdef(CONFIG_EVENTFD eventfd.c)
if(NOT (CONFIG_BOARD_NATIVE_POSIX OR CONFIG_BOARD_NATIVE_POSIX_64BIT))
zephyr_library_sources(nanosleep.c)
endif()
zephyr_library_include_directories(
${ZEPHYR_BASE}/kernel/include
${ZEPHYR_BASE}/arch/${ARCH}/include

60
lib/posix/nanosleep.c Normal file
View file

@ -0,0 +1,60 @@
/*
* Copyright (c) 2018 Friedt Professional Engineering Services, Inc
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <stdint.h>
#include <kernel.h>
#include <limits.h>
#include <errno.h>
/* required for struct timespec */
#include <posix/time.h>
#include <sys_clock.h>
/**
* @brief Suspend execution for nanosecond intervals.
*
* See IEEE 1003.1
*/
int nanosleep(const struct timespec *rqtp, struct timespec *rmtp)
{
uint64_t ns;
const bool update_rmtp = rmtp != NULL;
if (rqtp == NULL) {
errno = EFAULT;
return -1;
}
if (rqtp->tv_sec < 0 || rqtp->tv_nsec < 0
|| rqtp->tv_nsec >= NSEC_PER_SEC) {
errno = EINVAL;
return -1;
}
if (rqtp->tv_sec == 0 && rqtp->tv_nsec == 0) {
goto do_rmtp_update;
}
if (unlikely(rqtp->tv_sec >= ULLONG_MAX / NSEC_PER_SEC)) {
/* If a user passes this in, we could be here a while, but
* at least it's technically correct-ish
*/
ns = rqtp->tv_nsec + NSEC_PER_SEC;
k_sleep(K_SECONDS(rqtp->tv_sec - 1));
} else {
ns = rqtp->tv_sec * NSEC_PER_SEC + rqtp->tv_nsec;
}
/* currently we have no mechanism to achieve greater resolution */
k_busy_wait(ns / NSEC_PER_USEC);
do_rmtp_update:
if (update_rmtp) {
rmtp->tv_sec = 0;
rmtp->tv_nsec = 0;
}
return 0;
}