Fixed adjtime function: While using the adjtime() function, the time correction accumulated an error when reading the time frequently (using gettimeofday).
382 lines
12 KiB
C
382 lines
12 KiB
C
// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <errno.h>
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#include <stdlib.h>
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#include <time.h>
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#include <reent.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/reent.h>
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#include <sys/time.h>
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#include <sys/times.h>
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#include <sys/lock.h>
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#include <rom/rtc.h>
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#include "esp_attr.h"
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#include "esp_intr_alloc.h"
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#include "esp_clk.h"
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#include "esp_timer.h"
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#include "soc/soc.h"
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#include "soc/rtc.h"
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#include "soc/rtc_cntl_reg.h"
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#include "soc/frc_timer_reg.h"
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#include "rom/ets_sys.h"
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#include "freertos/FreeRTOS.h"
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#include "freertos/xtensa_api.h"
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#include "freertos/task.h"
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#include "sdkconfig.h"
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#include "limits.h"
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#if defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC ) || defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC_FRC1 )
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#define WITH_RTC 1
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#endif
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#if defined( CONFIG_ESP32_TIME_SYSCALL_USE_FRC1 ) || defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC_FRC1 )
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#define WITH_FRC 1
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#endif
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#ifdef WITH_RTC
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static uint64_t get_rtc_time_us()
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{
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const uint64_t ticks = rtc_time_get();
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const uint32_t cal = esp_clk_slowclk_cal_get();
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/* RTC counter result is up to 2^48, calibration factor is up to 2^24,
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* for a 32kHz clock. We need to calculate (assuming no overflow):
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* (ticks * cal) >> RTC_CLK_CAL_FRACT
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*
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* An overflow in the (ticks * cal) multiplication would cause time to
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* wrap around after approximately 13 days, which is probably not enough
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* for some applications.
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* Therefore multiplication is split into two terms, for the lower 32-bit
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* and the upper 16-bit parts of "ticks", i.e.:
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* ((ticks_low + 2^32 * ticks_high) * cal) >> RTC_CLK_CAL_FRACT
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*/
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const uint64_t ticks_low = ticks & UINT32_MAX;
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const uint64_t ticks_high = ticks >> 32;
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return ((ticks_low * cal) >> RTC_CLK_CAL_FRACT) +
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((ticks_high * cal) << (32 - RTC_CLK_CAL_FRACT));
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}
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#endif // WITH_RTC
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// s_boot_time: time from Epoch to the first boot time
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#ifdef WITH_RTC
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// when RTC is used to persist time, two RTC_STORE registers are used to store boot time
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#elif defined(WITH_FRC)
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static uint64_t s_boot_time;
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#endif // WITH_RTC
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#if defined(WITH_RTC) || defined(WITH_FRC)
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static _lock_t s_boot_time_lock;
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static _lock_t s_adjust_time_lock;
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// stores the start time of the slew
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static uint64_t adjtime_start = 0;
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// is how many microseconds total to slew
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static int64_t adjtime_total_correction = 0;
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#define ADJTIME_CORRECTION_FACTOR 6
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static uint64_t get_time_since_boot();
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#endif
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// Offset between FRC timer and the RTC.
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// Initialized after reset or light sleep.
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#if defined(WITH_RTC) && defined(WITH_FRC)
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uint64_t s_microseconds_offset;
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#endif
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#if defined(WITH_RTC) || defined(WITH_FRC)
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static void set_boot_time(uint64_t time_us)
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{
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_lock_acquire(&s_boot_time_lock);
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#ifdef WITH_RTC
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REG_WRITE(RTC_BOOT_TIME_LOW_REG, (uint32_t) (time_us & 0xffffffff));
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REG_WRITE(RTC_BOOT_TIME_HIGH_REG, (uint32_t) (time_us >> 32));
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#else
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s_boot_time = time_us;
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#endif
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_lock_release(&s_boot_time_lock);
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}
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static uint64_t get_boot_time()
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{
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uint64_t result;
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_lock_acquire(&s_boot_time_lock);
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#ifdef WITH_RTC
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result = ((uint64_t) REG_READ(RTC_BOOT_TIME_LOW_REG)) + (((uint64_t) REG_READ(RTC_BOOT_TIME_HIGH_REG)) << 32);
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#else
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result = s_boot_time;
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#endif
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_lock_release(&s_boot_time_lock);
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return result;
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}
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// This function gradually changes boot_time to the correction value and immediately updates it.
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static uint64_t adjust_boot_time()
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{
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uint64_t boot_time = get_boot_time();
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if ((boot_time == 0) || (get_time_since_boot() < adjtime_start)) {
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adjtime_start = 0;
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}
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if (adjtime_start > 0) {
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uint64_t since_boot = get_time_since_boot();
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// If to call this function once per second, then (since_boot - adjtime_start) will be 1_000_000 (1 second),
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// and the correction will be equal to (1_000_000us >> 6) = 15_625 us.
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// The minimum possible correction step can be (64us >> 6) = 1us.
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// Example: if the time error is 1 second, then it will be compensate for 1 sec / 0,015625 = 64 seconds.
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int64_t correction = (since_boot >> ADJTIME_CORRECTION_FACTOR) - (adjtime_start >> ADJTIME_CORRECTION_FACTOR);
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if (correction > 0) {
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adjtime_start = since_boot;
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if (adjtime_total_correction < 0) {
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if ((adjtime_total_correction + correction) >= 0) {
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boot_time = boot_time + adjtime_total_correction;
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adjtime_start = 0;
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} else {
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adjtime_total_correction += correction;
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boot_time -= correction;
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}
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} else {
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if ((adjtime_total_correction - correction) <= 0) {
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boot_time = boot_time + adjtime_total_correction;
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adjtime_start = 0;
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} else {
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adjtime_total_correction -= correction;
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boot_time += correction;
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}
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}
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set_boot_time(boot_time);
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}
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}
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return boot_time;
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}
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// Get the adjusted boot time.
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static uint64_t get_adjusted_boot_time (void)
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{
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_lock_acquire(&s_adjust_time_lock);
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uint64_t adjust_time = adjust_boot_time();
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_lock_release(&s_adjust_time_lock);
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return adjust_time;
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}
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// Applying the accumulated correction to boot_time and stopping the smooth time adjustment.
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static void adjtime_corr_stop (void)
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{
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_lock_acquire(&s_adjust_time_lock);
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if (adjtime_start != 0){
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adjust_boot_time();
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adjtime_start = 0;
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}
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_lock_release(&s_adjust_time_lock);
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}
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#endif //defined(WITH_RTC) || defined(WITH_FRC)
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int adjtime(const struct timeval *delta, struct timeval *outdelta)
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{
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#if defined( WITH_FRC ) || defined( WITH_RTC )
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if(delta != NULL){
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int64_t sec = delta->tv_sec;
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int64_t usec = delta->tv_usec;
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if(llabs(sec) > ((INT_MAX / 1000000L) - 1L)) {
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return -1;
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}
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/*
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* If adjusting the system clock by adjtime () is already done during the second call adjtime (),
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* and the delta of the second call is not NULL, the earlier tuning is stopped,
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* but the already completed part of the adjustment is not canceled.
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*/
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_lock_acquire(&s_adjust_time_lock);
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// If correction is already in progress (adjtime_start != 0), then apply accumulated corrections.
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adjust_boot_time();
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adjtime_start = get_time_since_boot();
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adjtime_total_correction = sec * 1000000L + usec;
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_lock_release(&s_adjust_time_lock);
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}
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if(outdelta != NULL){
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_lock_acquire(&s_adjust_time_lock);
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adjust_boot_time();
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if (adjtime_start != 0) {
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outdelta->tv_sec = adjtime_total_correction / 1000000L;
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outdelta->tv_usec = adjtime_total_correction % 1000000L;
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} else {
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outdelta->tv_sec = 0;
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outdelta->tv_usec = 0;
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}
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_lock_release(&s_adjust_time_lock);
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}
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return 0;
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#else
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return -1;
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#endif
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}
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void esp_clk_slowclk_cal_set(uint32_t new_cal)
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{
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#if defined(WITH_RTC)
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/* To force monotonic time values even when clock calibration value changes,
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* we adjust boot time, given current time and the new calibration value:
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* T = boot_time_old + cur_cal * ticks / 2^19
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* T = boot_time_adj + new_cal * ticks / 2^19
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* which results in:
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* boot_time_adj = boot_time_old + ticks * (cur_cal - new_cal) / 2^19
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*/
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const int64_t ticks = (int64_t) rtc_time_get();
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const uint32_t cur_cal = REG_READ(RTC_SLOW_CLK_CAL_REG);
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int32_t cal_diff = (int32_t) (cur_cal - new_cal);
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int64_t boot_time_diff = ticks * cal_diff / (1LL << RTC_CLK_CAL_FRACT);
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uint64_t boot_time_adj = get_boot_time() + boot_time_diff;
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set_boot_time(boot_time_adj);
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#endif // WITH_RTC
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REG_WRITE(RTC_SLOW_CLK_CAL_REG, new_cal);
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}
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uint32_t esp_clk_slowclk_cal_get()
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{
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return REG_READ(RTC_SLOW_CLK_CAL_REG);
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}
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void esp_set_time_from_rtc()
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{
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#if defined( WITH_FRC ) && defined( WITH_RTC )
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// initialize time from RTC clock
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s_microseconds_offset = get_rtc_time_us() - esp_timer_get_time();
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#endif // WITH_FRC && WITH_RTC
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}
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uint64_t esp_clk_rtc_time(void)
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{
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#ifdef WITH_RTC
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return get_rtc_time_us();
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#else
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return 0;
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#endif
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}
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clock_t IRAM_ATTR _times_r(struct _reent *r, struct tms *ptms)
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{
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clock_t t = xTaskGetTickCount() * (portTICK_PERIOD_MS * CLK_TCK / 1000);
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ptms->tms_cstime = 0;
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ptms->tms_cutime = 0;
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ptms->tms_stime = t;
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ptms->tms_utime = 0;
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struct timeval tv = {0, 0};
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_gettimeofday_r(r, &tv, NULL);
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return (clock_t) tv.tv_sec;
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}
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#if defined( WITH_FRC ) || defined( WITH_RTC )
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static uint64_t get_time_since_boot()
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{
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uint64_t microseconds = 0;
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#ifdef WITH_FRC
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#ifdef WITH_RTC
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microseconds = s_microseconds_offset + esp_timer_get_time();
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#else
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microseconds = esp_timer_get_time();
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#endif // WITH_RTC
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#elif defined(WITH_RTC)
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microseconds = get_rtc_time_us();
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#endif // WITH_FRC
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return microseconds;
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}
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#endif // defined( WITH_FRC ) || defined( WITH_RTC )
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int IRAM_ATTR _gettimeofday_r(struct _reent *r, struct timeval *tv, void *tz)
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{
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(void) tz;
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#if defined( WITH_FRC ) || defined( WITH_RTC )
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if (tv) {
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uint64_t microseconds = get_adjusted_boot_time() + get_time_since_boot();
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tv->tv_sec = microseconds / 1000000;
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tv->tv_usec = microseconds % 1000000;
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}
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return 0;
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#else
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__errno_r(r) = ENOSYS;
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return -1;
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#endif // defined( WITH_FRC ) || defined( WITH_RTC )
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}
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int settimeofday(const struct timeval *tv, const struct timezone *tz)
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{
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(void) tz;
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#if defined( WITH_FRC ) || defined( WITH_RTC )
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if (tv) {
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adjtime_corr_stop();
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uint64_t now = ((uint64_t) tv->tv_sec) * 1000000LL + tv->tv_usec;
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uint64_t since_boot = get_time_since_boot();
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set_boot_time(now - since_boot);
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}
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return 0;
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#else
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errno = ENOSYS;
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return -1;
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#endif
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}
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int usleep(useconds_t us)
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{
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const int us_per_tick = portTICK_PERIOD_MS * 1000;
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if (us < us_per_tick) {
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ets_delay_us((uint32_t) us);
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} else {
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/* since vTaskDelay(1) blocks for anywhere between 0 and portTICK_PERIOD_MS,
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* round up to compensate.
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*/
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vTaskDelay((us + us_per_tick - 1) / us_per_tick);
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}
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return 0;
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}
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unsigned int sleep(unsigned int seconds)
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{
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usleep(seconds*1000000UL);
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return 0;
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}
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uint32_t system_get_time(void)
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{
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#if defined( WITH_FRC ) || defined( WITH_RTC )
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return get_time_since_boot();
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#else
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return 0;
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#endif
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}
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uint32_t system_get_current_time(void) __attribute__((alias("system_get_time")));
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uint32_t system_relative_time(uint32_t current_time)
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{
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#if defined( WITH_FRC ) || defined( WITH_RTC )
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return get_time_since_boot() - current_time;
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#else
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return 0;
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#endif
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}
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uint64_t system_get_rtc_time(void)
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{
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#ifdef WITH_RTC
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return get_rtc_time_us();
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#else
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return 0;
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#endif
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}
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void esp_sync_counters_rtc_and_frc()
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{
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#if defined( WITH_FRC ) && defined( WITH_RTC )
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adjtime_corr_stop();
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int64_t s_microseconds_offset_cur = get_rtc_time_us() - esp_timer_get_time();
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set_boot_time(get_adjusted_boot_time() + ((int64_t)s_microseconds_offset - s_microseconds_offset_cur));
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#endif
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}
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