Merge pull request #8048 from naveenkaje/upstream_based_uart_fix_for_assert_test

NRF52: serial_api: Use polling for putc

Author: 0xc0170

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_NRF52/serial_api.c

@@ -1439,6 +1439,7 @@ int serial_getc(serial_t *obj)
  */
 void serial_putc(serial_t *obj, int character)
 {
+    bool done = false;
     MBED_ASSERT(obj);
 
 #if DEVICE_SERIAL_ASYNCH
@@ -1449,35 +1450,20 @@ void serial_putc(serial_t *obj, int character)
 
     int instance = uart_object->instance;
 
-    /**
-     * tx_in_progress acts like a mutex to ensure only one transmission can be active at a time.
-     * The flag is modified using the atomic compare-and-set function.
-     */
-    bool mutex = false;
-
-    do {
-        uint8_t expected = 0;
-        uint8_t desired = 1;
-
-        mutex = core_util_atomic_cas_u8((uint8_t *) &nordic_nrf5_uart_state[instance].tx_in_progress, &expected, desired);
-    } while (mutex == false);
-
-    /* Take ownership and configure UART if necessary. */
     nordic_nrf5_serial_configure(obj);
-
     /* Arm Tx DMA buffer. */
     nordic_nrf5_uart_state[instance].tx_data = character;
     nrf_uarte_tx_buffer_set(nordic_nrf5_uart_register[instance],
                             &nordic_nrf5_uart_state[instance].tx_data,
                             1);
-
-    /* Clear ENDTX event and enable interrupts. */
     nrf_uarte_event_clear(nordic_nrf5_uart_register[instance], NRF_UARTE_EVENT_ENDTX);
-    nrf_uarte_int_enable(nordic_nrf5_uart_register[instance], NRF_UARTE_INT_ENDTX_MASK);
+    nrf_uarte_task_trigger(nordic_nrf5_uart_register[instance], NRF_UARTE_TASK_STARTTX);
 
-    /* Trigger DMA transfer. */
-    nrf_uarte_task_trigger(nordic_nrf5_uart_register[instance],
-                           NRF_UARTE_TASK_STARTTX);
+    do {
+        done = nrf_uarte_event_extra_check(nordic_nrf5_uart_register[instance], NRF_UARTE_EVENT_TXDRDY);
+    } while(done == false);
+
+    nrf_uarte_event_extra_clear(nordic_nrf5_uart_register[instance], NRF_UARTE_EVENT_TXDRDY);
 }
 
 /** Check if the serial peripheral is readable

targets/TARGET_NORDIC/TARGET_NRF5x/TARGET_SDK_14_2/drivers_nrf/hal/nrf_uarte.h

@@ -228,6 +228,25 @@ __STATIC_INLINE void nrf_uarte_event_clear(NRF_UARTE_Type * p_reg, nrf_uarte_eve
  */
 __STATIC_INLINE bool nrf_uarte_event_check(NRF_UARTE_Type * p_reg, nrf_uarte_event_t event);
 
+/**
+ * @brief Function for checking the state of a specific extra UARTE event.
+ *
+ * @param[in] p_reg  Pointer to the peripheral registers structure.
+ * @param[in] event  Event to check.
+ *
+ * @retval True if event is set, False otherwise.
+ */
+__STATIC_INLINE bool nrf_uarte_event_extra_check(NRF_UARTE_Type * p_reg, uint32_t event);
+
+/**
+ * @brief Function for clearing a specific extra UARTE event.
+ *
+ * @param[in] p_reg  Pointer to the peripheral registers structure.
+ * @param[in] event  Extra event to clear.
+ */
+
+__STATIC_INLINE void nrf_uarte_event_extra_clear(NRF_UARTE_Type * p_reg, uint32_t event);
+
 /**
  * @brief Function for returning the address of a specific UARTE event register.
  *
@@ -456,11 +475,25 @@ __STATIC_INLINE void nrf_uarte_event_clear(NRF_UARTE_Type * p_reg, nrf_uarte_eve
 
 }
 
+__STATIC_INLINE void nrf_uarte_event_extra_clear(NRF_UARTE_Type * p_reg, uint32_t event)
+{
+    *((volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)event)) = 0x0UL;
+#if __CORTEX_M == 0x04
+    volatile uint32_t dummy = *((volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)event));
+    (void)dummy;
+#endif
+
+}
 __STATIC_INLINE bool nrf_uarte_event_check(NRF_UARTE_Type * p_reg, nrf_uarte_event_t event)
 {
     return (bool)*(volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)event);
 }
 
+__STATIC_INLINE bool nrf_uarte_event_extra_check(NRF_UARTE_Type * p_reg, uint32_t event)
+{
+    return (bool)*(volatile uint32_t *)((uint8_t *)p_reg + (uint32_t)event);
+}
+
 __STATIC_INLINE uint32_t nrf_uarte_event_address_get(NRF_UARTE_Type  * p_reg,
                                                     nrf_uarte_event_t  event)
 {