[U-Boot] [PATCH 2/4] serial: protect access to serial rx buffer

[Patrick Delaunay]

Add test to avoid access to rx buffer when this buffer is empty.
In this case directly call getc() function to avoid issue when tstc()
is not called.

Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
---

 drivers/serial/serial-uclass.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
index 321d23e..4121a37 100644
--- a/drivers/serial/serial-uclass.c
+++ b/drivers/serial/serial-uclass.c
@@ -228,6 +228,9 @@ static int _serial_getc(struct udevice *dev)
 	struct serial_dev_priv *upriv = dev_get_uclass_priv(dev);
 	char val;
 
+	if (upriv->rd_ptr == upriv->wr_ptr)
+		return __serial_getc(dev);
+
 	val = upriv->buf[upriv->rd_ptr++];
 	upriv->rd_ptr %= CONFIG_SERIAL_RX_BUFFER_SIZE;
 
-- 
2.7.4