newlib: separate low-level code in time.c implementation

components/newlib/CMakeLists.txt

@@ -20,6 +20,7 @@ list(APPEND ldfragments newlib.lf)
 
 idf_component_register(SRCS "${srcs}"
                     INCLUDE_DIRS "${include_dirs}"
+                    PRIV_INCLUDE_DIRS priv_include
                     PRIV_REQUIRES soc esp_timer
                     LDFRAGMENTS "${ldfragments}")  
 
@@ -40,3 +41,5 @@ target_link_libraries(${COMPONENT_LIB} INTERFACE "${EXTRA_LINK_FLAGS}")
 if(CONFIG_NEWLIB_NANO_FORMAT)
     target_link_libraries(${COMPONENT_LIB} INTERFACE "--specs=nano.specs")
 endif()
+
+add_subdirectory(port)

components/newlib/component.mk

@@ -12,6 +12,9 @@ ifdef CONFIG_SPIRAM_CACHE_WORKAROUND
 COMPONENT_ADD_LDFRAGMENTS := esp32-spiram-rom-functions-c.lf
 endif
 
+COMPONENT_PRIV_INCLUDEDIRS := priv_include
+COMPONENT_SRCDIRS := . port
+
 # Forces the linker to include locks, heap, and syscalls from this component,
 # instead of the implementations provided by newlib.
 COMPONENT_ADD_LDFLAGS += -u newlib_include_locks_impl

components/newlib/platform_include/esp_newlib.h

@@ -17,6 +17,11 @@
 
 #include <sys/reent.h>
 
+/*
+ * Initialize newlib time functions
+ */
+void esp_newlib_time_init(void);
+
 /**
  * Replacement for newlib's _REENT_INIT_PTR and __sinit.
  *

components/newlib/port/CMakeLists.txt

@@ -0,0 +1 @@
+target_sources(${COMPONENT_LIB} PRIVATE "${CMAKE_CURRENT_LIST_DIR}/esp_time_impl.c")

components/newlib/port/esp_time_impl.c

@@ -0,0 +1,207 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed 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.
+#include <stdint.h>
+#include <time.h>
+#include <sys/time.h>
+
+#include "esp_timer.h"
+
+#include "esp_system.h"
+
+#include "soc/spinlock.h"
+#include "soc/rtc.h"
+#include "esp_rom_sys.h"
+
+#include "esp_time_impl.h"
+
+#include "sdkconfig.h"
+
+#if CONFIG_IDF_TARGET_ESP32
+#include "esp32/rom/rtc.h"
+#include "esp32/clk.h"
+#elif CONFIG_IDF_TARGET_ESP32S2
+#include "esp32s2/rom/rtc.h"
+#include "esp32s2/clk.h"
+#endif
+
+#if defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC ) \
+    || defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC_FRC1 ) \
+    || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_RTC ) \
+    || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_RTC_FRC1 )
+#define WITH_RTC 1
+#endif
+
+#if defined( CONFIG_ESP32_TIME_SYSCALL_USE_FRC1 ) \
+    || defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC_FRC1 ) \
+    || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_FRC1 ) \
+    || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_RTC_FRC1 )
+#define WITH_FRC 1
+#endif
+
+// Offset between FRC timer and the RTC.
+// Initialized after reset or light sleep.
+#if defined(WITH_RTC) && defined(WITH_FRC)
+uint64_t s_microseconds_offset;
+#endif
+
+#ifndef WITH_RTC
+static uint64_t s_boot_time; // when RTC is used to persist time, two RTC_STORE registers are used to store boot time instead
+#endif
+
+static spinlock_t s_time_lock = SPINLOCK_INITIALIZER;
+
+#ifdef WITH_RTC
+static uint64_t get_rtc_time_us(void)
+{
+    const uint64_t ticks = rtc_time_get();
+    const uint32_t cal = esp_clk_slowclk_cal_get();
+    /* RTC counter result is up to 2^48, calibration factor is up to 2^24,
+     * for a 32kHz clock. We need to calculate (assuming no overflow):
+     *   (ticks * cal) >> RTC_CLK_CAL_FRACT
+     *
+     * An overflow in the (ticks * cal) multiplication would cause time to
+     * wrap around after approximately 13 days, which is probably not enough
+     * for some applications.
+     * Therefore multiplication is split into two terms, for the lower 32-bit
+     * and the upper 16-bit parts of "ticks", i.e.:
+     *   ((ticks_low + 2^32 * ticks_high) * cal) >> RTC_CLK_CAL_FRACT
+     */
+    const uint64_t ticks_low = ticks & UINT32_MAX;
+    const uint64_t ticks_high = ticks >> 32;
+    return ((ticks_low * cal) >> RTC_CLK_CAL_FRACT) +
+           ((ticks_high * cal) << (32 - RTC_CLK_CAL_FRACT));
+}
+#endif // WITH_RTC
+
+#if defined( WITH_FRC ) || defined( WITH_RTC )
+uint64_t esp_time_impl_get_time_since_boot(void)
+{
+    uint64_t microseconds = 0;
+
+#ifdef WITH_FRC
+#ifdef WITH_RTC
+    microseconds = s_microseconds_offset + esp_timer_get_time();
+#else
+    microseconds = esp_timer_get_time();
+#endif // WITH_RTC
+#elif defined(WITH_RTC)
+    microseconds = get_rtc_time_us();
+#endif // WITH_FRC
+    return microseconds;
+}
+
+uint64_t esp_time_impl_get_time(void)
+{
+#if defined( WITH_FRC )
+    return esp_timer_get_time();
+#elif defined( WITH_RTC )
+    return get_rtc_time_us();
+#endif // WITH_FRC
+}
+#endif // defined( WITH_FRC ) || defined( WITH_RTC )
+
+
+void esp_time_impl_set_boot_time(uint64_t time_us)
+{
+    spinlock_acquire(&s_time_lock, SPINLOCK_WAIT_FOREVER);
+#ifdef WITH_RTC
+    REG_WRITE(RTC_BOOT_TIME_LOW_REG, (uint32_t) (time_us & 0xffffffff));
+    REG_WRITE(RTC_BOOT_TIME_HIGH_REG, (uint32_t) (time_us >> 32));
+#else
+    s_boot_time = time_us;
+#endif
+    spinlock_release(&s_time_lock);
+}
+
+uint64_t esp_clk_rtc_time(void)
+{
+#ifdef WITH_RTC
+    return esp_rtc_get_time_us();
+#else
+    return 0;
+#endif
+}
+
+uint64_t esp_time_impl_get_boot_time(void)
+{
+    uint64_t result;
+    spinlock_acquire(&s_time_lock, SPINLOCK_WAIT_FOREVER);
+#ifdef WITH_RTC
+    result = ((uint64_t) REG_READ(RTC_BOOT_TIME_LOW_REG)) + (((uint64_t) REG_READ(RTC_BOOT_TIME_HIGH_REG)) << 32);
+#else
+    result = s_boot_time;
+#endif
+    spinlock_release(&s_time_lock);
+    return result;
+}
+
+uint32_t esp_clk_slowclk_cal_get(void)
+{
+    return REG_READ(RTC_SLOW_CLK_CAL_REG);
+}
+
+void esp_clk_slowclk_cal_set(uint32_t new_cal)
+{
+#if defined(WITH_RTC)
+    /* To force monotonic time values even when clock calibration value changes,
+     * we adjust boot time, given current time and the new calibration value:
+     *      T = boot_time_old + cur_cal * ticks / 2^19
+     *      T = boot_time_adj + new_cal * ticks / 2^19
+     * which results in:
+     *      boot_time_adj = boot_time_old + ticks * (cur_cal - new_cal) / 2^19
+     */
+    const int64_t ticks = (int64_t) rtc_time_get();
+    const uint32_t cur_cal = REG_READ(RTC_SLOW_CLK_CAL_REG);
+    int32_t cal_diff = (int32_t) (cur_cal - new_cal);
+    int64_t boot_time_diff = ticks * cal_diff / (1LL << RTC_CLK_CAL_FRACT);
+    uint64_t boot_time_adj = esp_time_impl_get_boot_time() + boot_time_diff;
+    esp_time_impl_set_boot_time(boot_time_adj);
+#endif // WITH_RTC
+    REG_WRITE(RTC_SLOW_CLK_CAL_REG, new_cal);
+}
+
+void esp_set_time_from_rtc(void)
+{
+#if defined( WITH_FRC ) && defined( WITH_RTC )
+    // initialize time from RTC clock
+    s_microseconds_offset = get_rtc_time_us() - esp_timer_get_time();
+#endif // WITH_FRC && WITH_RTC
+}
+
+void esp_sync_counters_rtc_and_frc(void)
+{
+#if defined( WITH_FRC ) && defined( WITH_RTC )
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    settimeofday(&tv, NULL);
+    int64_t s_microseconds_offset_cur = get_rtc_time_us() - esp_timer_get_time();
+    esp_time_impl_set_boot_time(esp_time_impl_get_boot_time() + ((int64_t)s_microseconds_offset - s_microseconds_offset_cur));
+#endif
+}
+
+void esp_time_impl_init(void)
+{
+    esp_set_time_from_rtc();
+}
+
+uint32_t esp_time_impl_get_time_resolution(void)
+{
+#if defined( WITH_FRC )
+    return 1L;
+#elif defined( WITH_RTC )
+    uint32_t rtc_freq = rtc_clk_slow_freq_get_hz();
+    assert(rtc_freq != 0);
+    return 1000000L / rtc_freq;
+#endif // WITH_FRC
+}

components/newlib/priv_include/esp_time_impl.h

@@ -0,0 +1,26 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed 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.
+#pragma once
+
+void esp_time_impl_init(void);
+
+uint64_t esp_time_impl_get_time(void);
+
+uint64_t esp_time_impl_get_time_since_boot(void);
+
+uint32_t esp_time_impl_get_time_resolution(void);
+
+void esp_time_impl_set_boot_time(uint64_t t);
+
+uint64_t esp_time_impl_get_boot_time(void);

components/newlib/test/test_time.c

@@ -13,6 +13,13 @@
 #include "test_utils.h"
 #include "esp_log.h"
 #include "esp_rom_sys.h"
+#include "esp_system.h"
+
+#if CONFIG_IDF_TARGET_ESP32
+#include "esp32/clk.h"
+#elif CONFIG_IDF_TARGET_ESP32S2
+#include "esp32s2/clk.h"
+#endif
 
 #if portNUM_PROCESSORS == 2
 
@@ -379,8 +386,8 @@ void test_posix_timers_clock (void)
     ts.tv_nsec = 100000000L;
     TEST_ASSERT(clock_settime(CLOCK_REALTIME, &ts) == 0);
     TEST_ASSERT(gettimeofday(&now, NULL) == 0);
-    TEST_ASSERT(now.tv_sec == ts.tv_sec);
-    TEST_ASSERT_INT_WITHIN(5000L, now.tv_usec,  ts.tv_nsec / 1000L);
+    TEST_ASSERT_EQUAL(ts.tv_sec, now.tv_sec);
+    TEST_ASSERT_INT_WITHIN(5000L, ts.tv_nsec / 1000L, now.tv_usec);
 
     TEST_ASSERT(clock_settime(CLOCK_MONOTONIC, &ts) == -1);
 

components/newlib/time.c

@@ -21,26 +21,18 @@
 #include <sys/reent.h>
 #include <sys/time.h>
 #include <sys/times.h>
-#include <sys/lock.h>
+
 #include "esp_attr.h"
-#include "esp_intr_alloc.h"
-#include "esp_timer.h"
-#include "soc/soc.h"
-#include "soc/rtc.h"
-#include "soc/frc_timer_reg.h"
+
 #include "freertos/FreeRTOS.h"
-#include "freertos/xtensa_api.h"
 #include "freertos/task.h"
-#include "limits.h"
+
+#include "soc/spinlock.h"
+#include "soc/rtc.h"
+
+#include "esp_time_impl.h"
+
 #include "sdkconfig.h"
-#include "esp_rom_sys.h"
-#if CONFIG_IDF_TARGET_ESP32
-#include "esp32/clk.h"
-#include "esp32/rom/rtc.h"
-#elif CONFIG_IDF_TARGET_ESP32S2
-#include "esp32s2/clk.h"
-#include "esp32s2/rom/rtc.h"
-#endif
 
 #ifdef CONFIG_SDK_TOOLCHAIN_SUPPORTS_TIME_WIDE_64_BITS
 _Static_assert(sizeof(time_t) == 8, "The toolchain does not support time_t wide 64-bits");
@@ -48,161 +40,95 @@ _Static_assert(sizeof(time_t) == 8, "The toolchain does not support time_t wide
 _Static_assert(sizeof(time_t) == 4, "The toolchain supports time_t wide 64-bits. Please enable CONFIG_SDK_TOOLCHAIN_SUPPORTS_TIME_WIDE_64_BITS.");
 #endif
 
-#if defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC ) || defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC_FRC1 ) || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_RTC ) || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_RTC_FRC1 )
-#define WITH_RTC 1
+#if !CONFIG_ESP32_TIME_SYSCALL_USE_NONE && !CONFIG_ESP32S2_TIME_SYSCALL_USE_NONE
+#define IMPL_NEWLIB_TIME_FUNCS 1
 #endif
 
-#if defined( CONFIG_ESP32_TIME_SYSCALL_USE_FRC1 ) || defined( CONFIG_ESP32_TIME_SYSCALL_USE_RTC_FRC1 ) || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_FRC1 ) || defined( CONFIG_ESP32S2_TIME_SYSCALL_USE_RTC_FRC1 )
-#define WITH_FRC 1
-#endif
-
-#ifdef WITH_RTC
-static uint64_t get_rtc_time_us(void)
-{
-    const uint64_t ticks = rtc_time_get();
-    const uint32_t cal = esp_clk_slowclk_cal_get();
-    /* RTC counter result is up to 2^48, calibration factor is up to 2^24,
-     * for a 32kHz clock. We need to calculate (assuming no overflow):
-     *   (ticks * cal) >> RTC_CLK_CAL_FRACT
-     *
-     * An overflow in the (ticks * cal) multiplication would cause time to
-     * wrap around after approximately 13 days, which is probably not enough
-     * for some applications.
-     * Therefore multiplication is split into two terms, for the lower 32-bit
-     * and the upper 16-bit parts of "ticks", i.e.:
-     *   ((ticks_low + 2^32 * ticks_high) * cal) >> RTC_CLK_CAL_FRACT
-     */
-    const uint64_t ticks_low = ticks & UINT32_MAX;
-    const uint64_t ticks_high = ticks >> 32;
-    return ((ticks_low * cal) >> RTC_CLK_CAL_FRACT) +
-           ((ticks_high * cal) << (32 - RTC_CLK_CAL_FRACT));
-}
-#endif // WITH_RTC
-
-
-// s_boot_time: time from Epoch to the first boot time
-#ifdef WITH_RTC
-// when RTC is used to persist time, two RTC_STORE registers are used to store boot time
-#elif defined(WITH_FRC)
-static uint64_t s_boot_time;
-#endif // WITH_RTC
-
-#if defined(WITH_RTC) || defined(WITH_FRC)
-static _lock_t s_boot_time_lock;
-static _lock_t s_adjust_time_lock;
+#if IMPL_NEWLIB_TIME_FUNCS
 // stores the start time of the slew
-static uint64_t adjtime_start = 0;
+static uint64_t s_adjtime_start_us;
 // is how many microseconds total to slew
-static int64_t adjtime_total_correction = 0;
-#define ADJTIME_CORRECTION_FACTOR 6
-static uint64_t get_time_since_boot(void);
-#endif
-// Offset between FRC timer and the RTC.
-// Initialized after reset or light sleep.
-#if defined(WITH_RTC) && defined(WITH_FRC)
-uint64_t s_microseconds_offset;
-#endif
+static int64_t  s_adjtime_total_correction_us;
 
-#if defined(WITH_RTC) || defined(WITH_FRC)
-static void set_boot_time(uint64_t time_us)
-{
-    _lock_acquire(&s_boot_time_lock);
-#ifdef WITH_RTC
-    REG_WRITE(RTC_BOOT_TIME_LOW_REG, (uint32_t) (time_us & 0xffffffff));
-    REG_WRITE(RTC_BOOT_TIME_HIGH_REG, (uint32_t) (time_us >> 32));
-#else
-    s_boot_time = time_us;
-#endif
-    _lock_release(&s_boot_time_lock);
-}
-
-static uint64_t get_boot_time(void)
-{
-    uint64_t result;
-    _lock_acquire(&s_boot_time_lock);
-#ifdef WITH_RTC
-    result = ((uint64_t) REG_READ(RTC_BOOT_TIME_LOW_REG)) + (((uint64_t) REG_READ(RTC_BOOT_TIME_HIGH_REG)) << 32);
-#else
-    result = s_boot_time;
-#endif
-    _lock_release(&s_boot_time_lock);
-    return result;
-}
+static spinlock_t s_time_lock = SPINLOCK_INITIALIZER;
 
 // This function gradually changes boot_time to the correction value and immediately updates it.
 static uint64_t adjust_boot_time(void)
 {
-    uint64_t boot_time = get_boot_time();
-    if ((boot_time == 0) || (get_time_since_boot() < adjtime_start)) {
-        adjtime_start = 0;
+    #define ADJTIME_CORRECTION_FACTOR 6
+
+    uint64_t boot_time = esp_time_impl_get_boot_time();
+    if ((boot_time == 0) || (esp_time_impl_get_time_since_boot() < s_adjtime_start_us)) {
+        s_adjtime_start_us = 0;
     }
-    if (adjtime_start > 0) {
-        uint64_t since_boot = get_time_since_boot();
-        // If to call this function once per second, then (since_boot - adjtime_start) will be 1_000_000 (1 second),
+    if (s_adjtime_start_us > 0) {
+        uint64_t since_boot = esp_time_impl_get_time_since_boot();
+        // If to call this function once per second, then (since_boot - s_adjtime_start_us) will be 1_000_000 (1 second),
         // and the correction will be equal to (1_000_000us >> 6) = 15_625 us.
         // The minimum possible correction step can be (64us >> 6) = 1us.
         // Example: if the time error is 1 second, then it will be compensate for 1 sec / 0,015625 = 64 seconds.
-        int64_t correction = (since_boot >> ADJTIME_CORRECTION_FACTOR) - (adjtime_start >> ADJTIME_CORRECTION_FACTOR);
+        int64_t correction = (since_boot >> ADJTIME_CORRECTION_FACTOR) - (s_adjtime_start_us >> ADJTIME_CORRECTION_FACTOR);
         if (correction > 0) {
-            adjtime_start = since_boot;
-            if (adjtime_total_correction < 0) {
-                if ((adjtime_total_correction + correction) >= 0) {
-                    boot_time = boot_time + adjtime_total_correction;
-                    adjtime_start = 0;
+            s_adjtime_start_us = since_boot;
+            if (s_adjtime_total_correction_us < 0) {
+                if ((s_adjtime_total_correction_us + correction) >= 0) {
+                    boot_time = boot_time + s_adjtime_total_correction_us;
+                    s_adjtime_start_us = 0;
                 } else {
-                    adjtime_total_correction += correction;
+                    s_adjtime_total_correction_us += correction;
                     boot_time -= correction;
                 }
             } else {
-                if ((adjtime_total_correction - correction) <= 0) {
-                    boot_time = boot_time + adjtime_total_correction;
-                    adjtime_start = 0;
+                if ((s_adjtime_total_correction_us - correction) <= 0) {
+                    boot_time = boot_time + s_adjtime_total_correction_us;
+                    s_adjtime_start_us = 0;
                 } else {
-                    adjtime_total_correction -= correction;
+                    s_adjtime_total_correction_us -= correction;
                     boot_time += correction;
                 }
             }
-            set_boot_time(boot_time);
+            esp_time_impl_set_boot_time(boot_time);
         }
     }
     return boot_time;
 }
 
+
 // Get the adjusted boot time.
-static uint64_t get_adjusted_boot_time (void)
+static uint64_t get_adjusted_boot_time(void)
 {
-    _lock_acquire(&s_adjust_time_lock);
+    spinlock_acquire(&s_time_lock, SPINLOCK_WAIT_FOREVER);
     uint64_t adjust_time = adjust_boot_time();
-    _lock_release(&s_adjust_time_lock);
+    spinlock_release(&s_time_lock);
     return adjust_time;
 }
 
-// Applying the accumulated correction to boot_time and stopping the smooth time adjustment.
+// Applying the accumulated correction to base_time and stopping the smooth time adjustment.
 static void adjtime_corr_stop (void)
 {
-    _lock_acquire(&s_adjust_time_lock);
-    if (adjtime_start != 0){
+    spinlock_acquire(&s_time_lock, SPINLOCK_WAIT_FOREVER);
+    if (s_adjtime_start_us != 0){
         adjust_boot_time();
-        adjtime_start = 0;
+        s_adjtime_start_us = 0;
     }
-    _lock_release(&s_adjust_time_lock);
+    spinlock_release(&s_time_lock);
 }
-#endif //defined(WITH_RTC) || defined(WITH_FRC)
+#endif
 
 int adjtime(const struct timeval *delta, struct timeval *outdelta)
 {
-#if defined( WITH_FRC ) || defined( WITH_RTC )
+#if IMPL_NEWLIB_TIME_FUNCS
     if(outdelta != NULL){
-        _lock_acquire(&s_adjust_time_lock);
+        spinlock_acquire(&s_time_lock, SPINLOCK_WAIT_FOREVER);
         adjust_boot_time();
-        if (adjtime_start != 0) {
-            outdelta->tv_sec    = adjtime_total_correction / 1000000L;
-            outdelta->tv_usec   = adjtime_total_correction % 1000000L;
+        if (s_adjtime_start_us != 0) {
+            outdelta->tv_sec    = s_adjtime_total_correction_us / 1000000L;
+            outdelta->tv_usec   = s_adjtime_total_correction_us % 1000000L;
         } else {
             outdelta->tv_sec    = 0;
             outdelta->tv_usec   = 0;
         }
-        _lock_release(&s_adjust_time_lock);
+        spinlock_release(&s_time_lock);
     }
     if(delta != NULL){
         int64_t sec  = delta->tv_sec;
@@ -215,59 +141,16 @@ int adjtime(const struct timeval *delta, struct timeval *outdelta)
         * and the delta of the second call is not NULL, the earlier tuning is stopped,
         * but the already completed part of the adjustment is not canceled.
         */
-        _lock_acquire(&s_adjust_time_lock);
-        // If correction is already in progress (adjtime_start != 0), then apply accumulated corrections.
+        spinlock_acquire(&s_time_lock, SPINLOCK_WAIT_FOREVER);
+        // If correction is already in progress (s_adjtime_start_time_us != 0), then apply accumulated corrections.
         adjust_boot_time();
-        adjtime_start = get_time_since_boot();
-        adjtime_total_correction = sec * 1000000L + usec;
-        _lock_release(&s_adjust_time_lock);
+        s_adjtime_start_us = esp_time_impl_get_time_since_boot();
+        s_adjtime_total_correction_us = sec * 1000000L + usec;
+        spinlock_release(&s_time_lock);
     }
-  return 0;
-#else
-  return -1;
-#endif
-
-}
-
-void esp_clk_slowclk_cal_set(uint32_t new_cal)
-{
-#if defined(WITH_RTC)
-    /* To force monotonic time values even when clock calibration value changes,
-     * we adjust boot time, given current time and the new calibration value:
-     *      T = boot_time_old + cur_cal * ticks / 2^19
-     *      T = boot_time_adj + new_cal * ticks / 2^19
-     * which results in:
-     *      boot_time_adj = boot_time_old + ticks * (cur_cal - new_cal) / 2^19
-     */
-    const int64_t ticks = (int64_t) rtc_time_get();
-    const uint32_t cur_cal = REG_READ(RTC_SLOW_CLK_CAL_REG);
-    int32_t cal_diff = (int32_t) (cur_cal - new_cal);
-    int64_t boot_time_diff = ticks * cal_diff / (1LL << RTC_CLK_CAL_FRACT);
-    uint64_t boot_time_adj = get_boot_time() + boot_time_diff;
-    set_boot_time(boot_time_adj);
-#endif // WITH_RTC
-    REG_WRITE(RTC_SLOW_CLK_CAL_REG, new_cal);
-}
-
-uint32_t esp_clk_slowclk_cal_get(void)
-{
-    return REG_READ(RTC_SLOW_CLK_CAL_REG);
-}
-
-void esp_set_time_from_rtc(void)
-{
-#if defined( WITH_FRC ) && defined( WITH_RTC )
-    // initialize time from RTC clock
-    s_microseconds_offset = get_rtc_time_us() - esp_timer_get_time();
-#endif // WITH_FRC && WITH_RTC
-}
-
-uint64_t esp_clk_rtc_time(void)
-{
-#ifdef WITH_RTC
-    return get_rtc_time_us();
-#else
     return 0;
+#else
+    return -1;
 #endif
 }
 
@@ -283,29 +166,13 @@ clock_t IRAM_ATTR _times_r(struct _reent *r, struct tms *ptms)
     return (clock_t) tv.tv_sec;
 }
 
-#if defined( WITH_FRC ) || defined( WITH_RTC )
-static uint64_t get_time_since_boot(void)
-{
-    uint64_t microseconds = 0;
-#ifdef WITH_FRC
-#ifdef WITH_RTC
-    microseconds = s_microseconds_offset + esp_timer_get_time();
-#else
-    microseconds = esp_timer_get_time();
-#endif // WITH_RTC
-#elif defined(WITH_RTC)
-    microseconds = get_rtc_time_us();
-#endif // WITH_FRC
-    return microseconds;
-}
-#endif // defined( WITH_FRC ) || defined( WITH_RTC )
-
 int IRAM_ATTR _gettimeofday_r(struct _reent *r, struct timeval *tv, void *tz)
 {
     (void) tz;
-#if defined( WITH_FRC ) || defined( WITH_RTC )
+
+#if IMPL_NEWLIB_TIME_FUNCS
     if (tv) {
-        uint64_t microseconds = get_adjusted_boot_time() + get_time_since_boot();
+        uint64_t microseconds = get_adjusted_boot_time() + esp_time_impl_get_time_since_boot();
         tv->tv_sec = microseconds / 1000000;
         tv->tv_usec = microseconds % 1000000;
     }
@@ -313,18 +180,18 @@ int IRAM_ATTR _gettimeofday_r(struct _reent *r, struct timeval *tv, void *tz)
 #else
     __errno_r(r) = ENOSYS;
     return -1;
-#endif // defined( WITH_FRC ) || defined( WITH_RTC )
+#endif
 }
 
 int settimeofday(const struct timeval *tv, const struct timezone *tz)
 {
     (void) tz;
-#if defined( WITH_FRC ) || defined( WITH_RTC )
+#if IMPL_NEWLIB_TIME_FUNCS
     if (tv) {
         adjtime_corr_stop();
         uint64_t now = ((uint64_t) tv->tv_sec) * 1000000LL + tv->tv_usec;
-        uint64_t since_boot = get_time_since_boot();
-        set_boot_time(now - since_boot);
+        uint64_t since_boot = esp_time_impl_get_time_since_boot();
+        esp_time_impl_set_boot_time(now - since_boot);
     }
     return 0;
 #else
@@ -353,48 +220,9 @@ unsigned int sleep(unsigned int seconds)
     return 0;
 }
 
-uint32_t system_get_time(void)
-{
-#if defined( WITH_FRC ) || defined( WITH_RTC )
-    return get_time_since_boot();
-#else
-    return 0;
-#endif
-}
-
-uint32_t system_get_current_time(void) __attribute__((alias("system_get_time")));
-
-uint32_t system_relative_time(uint32_t current_time)
+int clock_settime(clockid_t clock_id, const struct timespec *tp)
 {
-#if defined( WITH_FRC ) || defined( WITH_RTC )
-    return get_time_since_boot() - current_time;
-#else
-    return 0;
-#endif
-}
-
-uint64_t system_get_rtc_time(void)
-{
-#ifdef WITH_RTC
-    return get_rtc_time_us();
-#else
-    return 0;
-#endif
-}
-
-void esp_sync_counters_rtc_and_frc(void)
-{
-#if defined( WITH_FRC ) && defined( WITH_RTC )
-    adjtime_corr_stop();
-    int64_t s_microseconds_offset_cur = get_rtc_time_us() - esp_timer_get_time();
-    set_boot_time(get_adjusted_boot_time() + ((int64_t)s_microseconds_offset - s_microseconds_offset_cur));
-#endif
-}
-
-
-int clock_settime (clockid_t clock_id, const struct timespec *tp)
-{
-#if defined( WITH_FRC ) || defined( WITH_RTC )
+#if IMPL_NEWLIB_TIME_FUNCS
     if (tp == NULL) {
         errno = EINVAL;
         return -1;
@@ -419,7 +247,7 @@ int clock_settime (clockid_t clock_id, const struct timespec *tp)
 
 int clock_gettime (clockid_t clock_id, struct timespec *tp)
 {
-#if defined( WITH_FRC ) || defined( WITH_RTC )
+#if IMPL_NEWLIB_TIME_FUNCS
     if (tp == NULL) {
         errno = EINVAL;
         return -1;
@@ -433,11 +261,7 @@ int clock_gettime (clockid_t clock_id, struct timespec *tp)
             tp->tv_nsec = tv.tv_usec * 1000L;
             break;
         case CLOCK_MONOTONIC:
-#if defined( WITH_FRC )
-            monotonic_time_us = (uint64_t) esp_timer_get_time();
-#elif defined( WITH_RTC )
-            monotonic_time_us = get_rtc_time_us();
-#endif // WITH_FRC
+            monotonic_time_us = esp_time_impl_get_time();
             tp->tv_sec = monotonic_time_us / 1000000LL;
             tp->tv_nsec = (monotonic_time_us % 1000000LL) * 1000L;
             break;
@@ -454,23 +278,23 @@ int clock_gettime (clockid_t clock_id, struct timespec *tp)
 
 int clock_getres (clockid_t clock_id, struct timespec *res)
 {
-#if defined( WITH_FRC ) || defined( WITH_RTC )
+#if IMPL_NEWLIB_TIME_FUNCS
     if (res == NULL) {
         errno = EINVAL;
         return -1;
     }
-#if defined( WITH_FRC )
-    res->tv_sec = 0;
-    res->tv_nsec = 1000L;
-#elif defined( WITH_RTC )
+
     res->tv_sec = 0;
-    uint32_t rtc_freq = rtc_clk_slow_freq_get_hz();
-    assert(rtc_freq != 0);
-    res->tv_nsec = 1000000000L / rtc_freq;
-#endif // WITH_FRC
+    res->tv_nsec = esp_time_impl_get_time_resolution() * 1000;
+
     return 0;
 #else
     errno = ENOSYS;
     return -1;
 #endif
 }
+
+void esp_newlib_time_init(void)
+{
+    esp_time_impl_init();
+}