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);