Merge branch 'feature/add_cpu_wait_for_low_power' into 'master'

Add CPU wait to save power

See merge request sdk/ESP8266_RTOS_SDK!912

components/esp8266/include/driver/soc.h

@@ -128,6 +128,16 @@ static inline uint32_t soc_get_int_mask(void)
     return mask & enable & ETS_INT_MASK;
 }
 
+static inline void soc_wait_int(void)
+{
+    __asm__ __volatile__(
+            "waiti  0\n"
+            :
+            :
+            : "memory"
+    );
+}
+
 #ifdef __cplusplus
 }
 #endif

components/freertos/port/esp8266/port.c

@@ -342,6 +342,8 @@ void esp_internal_idle_hook(void)
 
     esp_task_wdt_reset();
     pmIdleHook();
+
+    soc_wait_int();
 }
 
 #ifndef DISABLE_FREERTOS