67 lines
2.5 KiB
C
67 lines
2.5 KiB
C
// Copyright (c) 2014 Adafruit Industries
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// Author: Tony DiCola
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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#include <errno.h>
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#include <sched.h>
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#include <string.h>
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#include <sys/time.h>
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#include <time.h>
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#include "common_dht_read.h"
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void busy_wait_milliseconds(uint32_t millis) {
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// Set delay time period.
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struct timeval deltatime;
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deltatime.tv_sec = millis / 1000;
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deltatime.tv_usec = (millis % 1000) * 1000;
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struct timeval walltime;
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// Get current time and add delay to find end time.
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gettimeofday(&walltime, NULL);
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struct timeval endtime;
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timeradd(&walltime, &deltatime, &endtime);
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// Tight loop to waste time (and CPU) until enough time as elapsed.
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while (timercmp(&walltime, &endtime, <)) {
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gettimeofday(&walltime, NULL);
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}
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}
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void sleep_milliseconds(uint32_t millis) {
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struct timespec sleep;
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sleep.tv_sec = millis / 1000;
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sleep.tv_nsec = (millis % 1000) * 1000000L;
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while (clock_nanosleep(CLOCK_MONOTONIC, 0, &sleep, &sleep) && errno == EINTR);
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}
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void set_max_priority(void) {
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struct sched_param sched;
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memset(&sched, 0, sizeof(sched));
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// Use FIFO scheduler with highest priority for the lowest chance of the kernel context switching.
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sched.sched_priority = sched_get_priority_max(SCHED_FIFO);
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sched_setscheduler(0, SCHED_FIFO, &sched);
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}
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void set_default_priority(void) {
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struct sched_param sched;
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memset(&sched, 0, sizeof(sched));
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// Go back to default scheduler with default 0 priority.
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sched.sched_priority = 0;
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sched_setscheduler(0, SCHED_OTHER, &sched);
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}
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