use settimeofday's tv->usec (esp8266#1679)

Author: d-a-v

cores/esp8266/coredecls.h

@@ -6,10 +6,11 @@
 extern "C" {
 #endif
 
-extern bool s_bootTimeSet;
-
 // TODO: put declarations here, get rid of -Wno-implicit-function-declaration
 
+extern bool timeshift64_is_set;
+
+void tune_timeshift64 (uint64_t now_us);
 void sntp_force_request (void);
 void settimeofday_cb (void (*cb)(void));
 

cores/esp8266/sntp-lwip2.c

@@ -66,10 +66,11 @@ int settimeofday(const struct timeval* tv, const struct timezone* tz)
     }
     if (tv) /* after*/
     {
+        // can't call lwip1.4's static sntp_set_system_time()
         os_printf(stod14);
 
         // reset time subsystem
-        s_bootTimeSet = false;
+        timeshift64_is_set = false;
 
         return -1;
     }
@@ -448,11 +449,10 @@ int settimeofday(const struct timeval* tv, const struct timezone* tz)
     }
     if (tv) /* after*/
     {
-        sntp_set_system_time(tv->tv_sec);
-        // XXX FIXME TODO: efficiently use provided tv->tv_sec
-        
         // reset time subsystem
-        s_bootTimeSet = false;
+        tune_timeshift64(tv->tv_sec * 1000000ULL + tv->tv_usec);
+
+        sntp_set_system_time(tv->tv_sec);
 
         if (_settimeofday_cb)
             _settimeofday_cb();

cores/esp8266/time.c

@@ -37,22 +37,13 @@ extern uint64_t micros64();
 // time gap in seconds from 01.01.1900 (NTP time) to 01.01.1970 (UNIX time)
 #define DIFF1900TO1970 2208988800UL
 
-bool s_bootTimeSet = false;
-static uint64_t s_bootTime_us = 0;
+bool timeshift64_is_set = false;
+static uint64_t timeshift64 = 0;
 
-// calculate offset used in gettimeofday
-static void ensureBootTimeIsSet()
+void tune_timeshift64 (uint64_t now_us)
 {
-    // Check just a bool flag instead of the full 64-bit s_bootTime for zero.
-    if (!s_bootTimeSet)
-    {
-        time_t now_s = sntp_get_current_timestamp();
-        if (now_s)
-        {
-            s_bootTime_us = now_s * 1000000ULL - micros64();
-            s_bootTimeSet = true;
-        }
-    }
+     timeshift64 = now_us - micros64();
+     timeshift64_is_set = true;
 }
 
 static void setServer(int id, const char* name_or_ip)
@@ -102,8 +93,9 @@ int _gettimeofday_r(struct _reent* unused, struct timeval *tp, void *tzp)
     (void) tzp;
     if (tp)
     {
-        ensureBootTimeIsSet();
-        uint64_t currentTime_us = s_bootTime_us + micros64();
+        if (!timeshift64_is_set)
+            tune_timeshift64(sntp_get_current_timestamp() * 1000000ULL);
+        uint64_t currentTime_us = timeshift64 + micros64();
         tp->tv_sec = currentTime_us / 1000000ULL;
         tp->tv_usec = currentTime_us % 1000000ULL;
     }

libraries/esp8266/examples/NTP-TZ-DST/NTP-TZ-DST.ino

@@ -36,8 +36,13 @@
 #define TZ_SEC          ((TZ)*3600)
 #define DST_SEC         ((DST_MN)*60)
 
+timeval cbtime;			// time set in callback
+bool cbtime_set = false;
+
 void time_is_set (void)
 {
+  gettimeofday(&cbtime, NULL);
+  cbtime_set = true;
   Serial.println("------------------ settimeofday() was called ------------------");
 }
 
@@ -103,6 +108,17 @@ void loop() {
     Serial.println();
     Serial.println();
   }
+  
+  if (cbtime_set)
+  {
+    Serial.print("gettimeofday at time-is-set-callback:");
+    Serial.print((uint32_t)cbtime.tv_sec);
+    Serial.print("/");
+    Serial.print((uint32_t)cbtime.tv_usec);
+    Serial.println("us");
+    Serial.println();
+    cbtime_set = false;
+  }
 
   // time from boot
   Serial.print("clock:");
@@ -147,24 +163,24 @@ void loop() {
   if (loop_count == 130) // 130=>13secs
   {
     Serial.println("------------------ WIFI ON ------------------");
-    Serial.print("connected:");
-    Serial.println(WiFi.status() == WL_CONNECTED);
+
+    timeval backtothefuture = { 0, 0 };
+    settimeofday(&backtothefuture, nullptr);
+    now = time(nullptr);
+    Serial.print("reset time after settimeofday(0) (sec): ");
+    Serial.println(now);
+
     WiFi.mode(WIFI_STA);
-    Serial.print("connected2:");
-    Serial.println(WiFi.status() == WL_CONNECTED);
     WiFi.begin(SSID, SSIDPWD);
+    Serial.print("reconnecting.");
     while (WiFi.status() != WL_CONNECTED)
     {
       delay(500);
       Serial.print(".");
     }
     Serial.println("reconnected");
-    timeval backtothefuture = { 0, 0 };
-    settimeofday(&backtothefuture, nullptr);
-    now = time(nullptr);
-    Serial.print("reset time: ");
-    Serial.println(now);
     loop_count = 0;
+
     sntp_force_request();
   }