fix(uart): check uart rx timeout value and log an error msg

Author: SuGlider

Diff for: cores/esp32/esp32-hal-uart.c

@@ -757,7 +757,11 @@ bool uartSetRxTimeout(uart_t *uart, uint8_t numSymbTimeout) {
   if (uart == NULL) {
     return false;
   }
-
+  uint16_t maxRXTimeout = uart_get_max_rx_timeout(uart->num);
+  if (numSymbTimeout > maxRXTimeout) {
+    log_e("Invalid RX Timeout value, its limit is %d", maxRXTimeout);
+    return false;
+  }
   UART_MUTEX_LOCK();
   bool retCode = (ESP_OK == uart_set_rx_timeout(uart->num, numSymbTimeout));
   UART_MUTEX_UNLOCK();
@@ -1382,4 +1386,24 @@ int uart_send_msg_with_break(uint8_t uartNum, uint8_t *msg, size_t msgSize) {
   return uart_write_bytes_with_break(uartNum, (const void *)msg, msgSize, 12);
 }
 
+// returns the maximum valid uart RX Timeout based on the UART Source Clock and Baudrate
+uint16_t uart_get_max_rx_timeout(uint8_t uartNum) {
+  if (uartNum >= SOC_UART_NUM) {
+    log_e("UART%d does not exist. This device has %d UARTs, from 0 to %d.", uartNum, SOC_UART_NUM, SOC_UART_NUM - 1);
+    return (uint16_t) -1;
+  }
+  uint16_t tout_max_thresh = uart_ll_max_tout_thrd(UART_LL_GET_HW(uartNum));
+  uint8_t symbol_len = 1; // number of bits per symbol including start
+  uart_parity_t parity_mode;
+  uart_stop_bits_t stop_bit;
+  uart_word_length_t data_bit;
+  uart_ll_get_data_bit_num(UART_LL_GET_HW(uartNum), &data_bit);
+  uart_ll_get_stop_bits(UART_LL_GET_HW(uartNum), &stop_bit);
+  uart_ll_get_parity(UART_LL_GET_HW(uartNum), &parity_mode);
+  symbol_len += (data_bit < UART_DATA_BITS_MAX) ? (uint8_t)data_bit + 5 : 8;
+  symbol_len += (stop_bit > UART_STOP_BITS_1) ? 2 : 1;
+  symbol_len += (parity_mode > UART_PARITY_DISABLE) ? 1 : 0;
+  return (uint16_t) (tout_max_thresh / symbol_len);
+}
+
 #endif /* SOC_UART_SUPPORTED */