esp-open-rtos/extras/sntp/sntp_fun.c
2020-05-01 17:01:35 +02:00

138 lines
3.7 KiB
C

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