+#if CONFIG_IS_ENABLED(SERIAL_RX_BUFFER)
+static int _serial_tstc(struct udevice *dev)
+{
+ struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
+
+ /* Read all available chars into the RX buffer */
+ while (__serial_tstc(dev)) {
+ upriv->buf[upriv->wr_ptr++] = __serial_getc(dev);
+ upriv->wr_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
+ }
+
+ return upriv->rd_ptr != upriv->wr_ptr ? 1 : 0;
+}
+
+static int _serial_getc(struct udevice *dev)
+{
+ struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
+ char val;
+
+ val = upriv->buf[upriv->rd_ptr++];
+ upriv->rd_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
+
+ return val;
+}
+
+#else /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
+
+static int _serial_getc(struct udevice *dev)
+{
+ return __serial_getc(dev);
+}
+
+static int _serial_tstc(struct udevice *dev)
+{
+ return __serial_tstc(dev);
+}
+#endif /* CONFIG_IS_ENABLED(SERIAL_RX_BUFFER) */
+