uart: Add missing critical section wrappers around rx_buffered_len
The missing barriers caused uart_get_buffered_data_len() to (very rarely)
return a garbage value. When used in MicroPython, though, this caused
select() to return and a subsequent read() to stall indefinitely until
a char was actually available.
Closes
Merges
@@ -1295,7 +1295,9 @@ esp_err_t uart_get_buffered_data_len(uart_port_t uart_num, size_t *size)
{
ESP_RETURN_ON_FALSE((uart_num < UART_NUM_MAX), ESP_FAIL, UART_TAG, "uart_num error");
ESP_RETURN_ON_FALSE((p_uart_obj[uart_num]), ESP_FAIL, UART_TAG, "uart driver error");
+ UART_ENTER_CRITICAL(&(uart_context[uart_num].spinlock));
*size = p_uart_obj[uart_num]->rx_buffered_len;
+ UART_EXIT_CRITICAL(&(uart_context[uart_num].spinlock));
return ESP_OK;
}
@@ -1336,12 +1338,15 @@ esp_err_t uart_flush_input(uart_port_t uart_num)
}
data = (uint8_t*) xRingbufferReceive(p_uart->rx_ring_buf, &size, (portTickType) 0);
if(data == NULL) {
+ UART_ENTER_CRITICAL(&(uart_context[uart_num].spinlock));
if( p_uart_obj[uart_num]->rx_buffered_len != 0 ) {
- ESP_LOGE(UART_TAG, "rx_buffered_len error");
p_uart_obj[uart_num]->rx_buffered_len = 0;
+ UART_EXIT_CRITICAL(&(uart_context[uart_num].spinlock));
+ // this must be called outside the critical section
+ ESP_LOGE(UART_TAG, "rx_buffered_len error");
+ UART_ENTER_CRITICAL(&(uart_context[uart_num].spinlock));
}
//We also need to clear the `rx_buffer_full_flg` here.
- UART_ENTER_CRITICAL(&(uart_context[uart_num].spinlock));
p_uart_obj[uart_num]->rx_buffer_full_flg = false;
UART_EXIT_CRITICAL(&(uart_context[uart_num].spinlock));
break;
