feat(esp8266): Add API to get microseconds

components/esp8266/include/driver/soc.h

@@ -0,0 +1,68 @@
+// Copyright 2019-2020 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
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define ESP_TICKS_MAX   UINT32_MAX
+
+typedef uint32_t esp_tick_t;
+typedef uint32_t esp_irqflag_t;
+
+static inline esp_tick_t soc_get_ticks(void)
+{
+    esp_tick_t ticks;
+
+    __asm__ __volatile__(
+            "rsr    %0, ccount\n"
+            : "=a"(ticks)
+            :
+            : "memory"
+    );
+
+    return ticks;
+}
+
+static inline esp_irqflag_t soc_save_local_irq(void)
+{
+    esp_irqflag_t flag;
+
+    __asm__ __volatile__(
+            "rsil   %0, 1\n"
+            : "=a"(flag)
+            :
+            : "memory"
+    );
+
+    return flag;
+}
+
+static inline void soc_restore_local_irq(esp_irqflag_t flag)
+{
+    __asm__ __volatile__(
+            "wsr    %0, ps\n"
+            : 
+            : "a"(flag)
+            : "memory"
+    );
+}
+
+#ifdef __cplusplus
+}
+#endif

components/esp8266/include/esp_timer.h

@@ -187,6 +187,13 @@ esp_err_t esp_timer_stop(esp_timer_handle_t timer);
  */
 esp_err_t esp_timer_delete(esp_timer_handle_t timer);
 
+/**
+ * @brief Get time in microseconds since RTOS starts
+ * @return number of microseconds since RTOS starts starts (this normally
+ *          happens much early during application startup).
+ */
+int64_t esp_timer_get_time();
+
 #ifdef __cplusplus
 }
 #endif