59ee3d5975
This reworks the accounting of the time to address the wrapping of the rtc counter. It currently assumes that the time is accessed more frequently than the counter would wrap. It also adds a semaphore to synchronize access to the time storage.
114 lines
3.1 KiB
C
114 lines
3.1 KiB
C
/*
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* Auxiliary functions to handle date/time along with lwIP sntp implementation.
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*
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* Jesus Alonso (doragasu)
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*/
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#include <sys/reent.h>
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#include <sys/types.h>
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#include <sys/errno.h>
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#include <stdio.h>
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#include <espressif/esp_common.h>
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#include <esp/timer.h>
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#include <esp/rtc_regs.h>
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#include "FreeRTOS.h"
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#include "semphr.h"
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#include "sntp.h"
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#define TIMER_COUNT RTC.COUNTER
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// daylight settings
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// Base calculated with value obtained from NTP server (64 bits)
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#define sntp_base (*((uint64_t*)RTC.SCRATCH))
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// Timer value when sntp_base was obtained
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#define tim_ref (RTC.SCRATCH[2])
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// Calibration value
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#define cal (RTC.SCRATCH[3])
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// To protect access to the above.
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static xSemaphoreHandle sntp_sem = NULL;
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// Timezone related data.
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static struct timezone stz;
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// Implemented in sntp.c
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void sntp_init(void);
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// Sets time zone.
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// NOTE: Settings do not take effect until SNTP time is updated.
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void sntp_set_timezone(const struct timezone *tz) {
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if (tz) {
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stz = *tz;
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} else {
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stz.tz_minuteswest = 0;
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stz.tz_dsttime = 0;
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}
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}
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// Initialization
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void sntp_initialize(const struct timezone *tz) {
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if (tz) {
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stz = *tz;
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} else {
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stz.tz_minuteswest = 0;
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stz.tz_dsttime = 0;
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}
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sntp_base = 0;
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// To avoid div by 0 exceptions if requesting time before SNTP config
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cal = 1;
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tim_ref = TIMER_COUNT;
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vSemaphoreCreateBinary(sntp_sem);
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sntp_init();
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}
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// Return usecs.
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inline uint64_t sntp_get_rtc_time() {
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xSemaphoreTake(sntp_sem, portMAX_DELAY);
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uint32_t tim = TIMER_COUNT;
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// Assume the difference does not overflow in which case
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// wrapping of the RTC timer still yields a good difference.
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uint32_t diff = tim - tim_ref;
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tim_ref = tim;
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uint64_t diff_us = ((uint64_t)diff * cal) >> 12;
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uint64_t base = sntp_base + diff_us;
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sntp_base = base;
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xSemaphoreGive(sntp_sem);
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return base;
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}
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// Syscall implementation. doesn't seem to use tzp.
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int _gettimeofday_r(struct _reent *r, struct timeval *tp, void *tzp) {
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(void)r;
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// Syscall defined by xtensa newlib defines tzp as void*
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// So it looks like it is not used. Also check tp is not NULL
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if (tzp || !tp) return EINVAL;
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uint64_t base = sntp_get_rtc_time();
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tp->tv_sec = base / 1000000U;
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tp->tv_usec = base % 1000000U;
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return 0;
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}
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// Update RTC timer. Called by SNTP module each time it receives an update.
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void sntp_update_rtc(time_t t, uint32_t us) {
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// Apply daylight and timezone correction
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t += (stz.tz_minuteswest + stz.tz_dsttime * 60) * 60;
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int64_t sntp_correct = (uint64_t)us + (uint64_t)t * 1000000U;
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xSemaphoreTake(sntp_sem, portMAX_DELAY);
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uint32_t tim = TIMER_COUNT;
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// Assume the difference does not overflow in which case
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// wrapping of the RTC timer still yields a good difference.
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uint32_t diff = tim - tim_ref;
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tim_ref = tim;
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uint64_t diff_us = ((uint64_t)diff * cal) >> 12;
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uint64_t sntp_current = sntp_base + diff_us;
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sntp_base = sntp_correct;
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cal = sdk_system_rtc_clock_cali_proc();
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xSemaphoreGive(sntp_sem);
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printf("\nRTC Adjust: drift = %d usec, cal = %d\n", (int)(sntp_correct - sntp_current), cal);
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}
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