/**************************************************************************** * sched/clock/clock_gettime.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include "clock/clock.h" #ifdef CONFIG_CLOCK_TIMEKEEPING # include "clock/clock_timekeeping.h" #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: clock_gettime * * Description: * Clock Functions based on POSIX APIs * ****************************************************************************/ int clock_gettime(clockid_t clock_id, struct timespec *tp) { #ifndef CONFIG_CLOCK_TIMEKEEPING struct timespec ts; uint32_t carry; #endif int ret = OK; DEBUGASSERT(tp != NULL); /* CLOCK_MONOTONIC is an optional under POSIX: "If the Monotonic Clock * option is supported, all implementations shall support a clock_id * of CLOCK_MONOTONIC defined in . This clock represents the * monotonic clock for the system. For this clock, the value returned * by clock_gettime() represents the amount of time (in seconds and * nanoseconds) since an unspecified point in the past (for example, * system start-up time, or the Epoch). This point does not change * after system start-up time. The value of the CLOCK_MONOTONIC clock * cannot be set via clock_settime(). This function shall fail if it * is invoked with a clock_id argument of CLOCK_MONOTONIC." */ if (clock_id == CLOCK_MONOTONIC || clock_id == CLOCK_BOOTTIME) { /* The the time elapsed since the timer was initialized at power on * reset. */ ret = clock_systime_timespec(tp); } /* CLOCK_REALTIME - POSIX demands this to be present. CLOCK_REALTIME * represents the machine's best-guess as to the current wall-clock, * time-of-day time. This means that CLOCK_REALTIME can jump forward and * backward as the system time-of-day clock is changed. */ else if (clock_id == CLOCK_REALTIME) { /* Get the elapsed time since the time-of-day was last set. * clock_systime_timespec() provides the time since power was applied; * the bias value corresponds to the time when the time-of-day was * last set. */ #if defined(CONFIG_CLOCK_TIMEKEEPING) ret = clock_timekeeping_get_wall_time(tp); #else ret = clock_systime_timespec(&ts); if (ret == OK) { irqstate_t flags; /* Add the base time to this. The base time is the time-of-day * setting. When added to the elapsed time since the time-of-day * was last set, this gives us the current time. */ flags = spin_lock_irqsave(NULL); ts.tv_sec += (uint32_t)g_basetime.tv_sec; ts.tv_nsec += (uint32_t)g_basetime.tv_nsec; spin_unlock_irqrestore(NULL, flags); /* Handle carry to seconds. */ if (ts.tv_nsec >= NSEC_PER_SEC) { carry = ts.tv_nsec / NSEC_PER_SEC; ts.tv_sec += carry; ts.tv_nsec -= (carry * NSEC_PER_SEC); } /* And return the result to the caller. */ tp->tv_sec = ts.tv_sec; tp->tv_nsec = ts.tv_nsec; } #endif /* CONFIG_CLOCK_TIMEKEEPING */ } else { ret = -EINVAL; } /* Check for errors and set the errno value if necessary */ if (ret < 0) { set_errno(-ret); ret = ERROR; } return ret; }