Use esp_timer_get_time as time source for micros and mills (#1424)

esp_timer_get_time returns monotonic time in microseconds, as a 64-bit
number. It can be called from tasks and interrupts, does not use any
critical sections/mutexes, and is thread safe.

cores/esp32/esp32-hal-misc.c

@@ -21,7 +21,7 @@
 #include "nvs.h"
 #include "esp_partition.h"
 #include "esp_log.h"
-#include "pthread.h"
+#include "esp_timer.h"
 #include <sys/time.h>
 
 //Undocumented!!! Get chip temperature in Farenheit
@@ -38,51 +38,14 @@ void yield()
     vPortYield();
 }
 
-portMUX_TYPE microsMux = portMUX_INITIALIZER_UNLOCKED;
-static pthread_key_t microsStore=NULL; // Thread Local Storage Handle
-
-void microsStoreDelete(void * storage) {  // release thread local data when task is delete.
-    if(storage) free(storage);
-}
-
 unsigned long IRAM_ATTR micros()
 {
-    if (!microsStore) { // first Time Ever thread local not init'd
-        portENTER_CRITICAL_ISR(&microsMux);
-        pthread_key_create(&microsStore,microsStoreDelete); // create initial holder
-        portEXIT_CRITICAL_ISR(&microsMux);
-    }
-  
-    uint32_t *ptr;// [0] is lastCount, [1] is overFlow
-
-    ptr = pthread_getspecific(microsStore); // get address of storage
- 
-    if(ptr == NULL) { // first time in this thread, allocate mem, init it.  
-        portENTER_CRITICAL_ISR(&microsMux);
-        ptr = (uint32_t*)malloc(sizeof(uint32_t)*2);
-        pthread_setspecific(microsStore,ptr); // store the pointer to this thread's values
-        ptr[0] = 0; // lastCount value
-        ptr[1] = 0; // overFlow
-        portEXIT_CRITICAL_ISR(&microsMux);
-    }  
-
-    unsigned long ccount;
-    
-    portENTER_CRITICAL_ISR(&microsMux);
-    __asm__ __volatile__ ( "rsr     %0, ccount" : "=a" (ccount) ); //get cycle count
-    if(ccount < ptr[0]) { // overflow occurred
-        ptr[1] += UINT32_MAX / CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ;
-    }
-    
-    ptr[0] = ccount;
-    portEXIT_CRITICAL_ISR(&microsMux);
-
-    return ptr[1] + (ccount / CONFIG_ESP32_DEFAULT_CPU_FREQ_MHZ);
+    return (unsigned long) esp_timer_get_time();
 }
 
 unsigned long IRAM_ATTR millis()
 {
-    return xTaskGetTickCount() * portTICK_PERIOD_MS;
+    return (unsigned long) (esp_timer_get_time() / 1000);
 }
 
 void delay(uint32_t ms)

cores/esp32/main.cpp

@@ -14,7 +14,6 @@ void loopTask(void *pvParameters)
 {
     setup();
     for(;;) {
-        micros(); //update overflow
         loop();
     }
 }