arm: vf610: lpuart: disable FIFO on initializaton
UART does not use the UART FIFO, but we should also not rely that
the UART FIFO is diabled by default. For instance, when loading
U-Boot using the boot ROMs serial downloader protocol over UART,
FIFO is enabled at U-Boot start time.
This patch disables the RX and TX FIFO, sets back their thresholds
and flushes them.
Signed-off-by: Stefan Agner <stefan@agner.ch>
diff --git a/drivers/serial/serial_lpuart.c b/drivers/serial/serial_lpuart.c
index 96173ca..0a5e159 100644
--- a/drivers/serial/serial_lpuart.c
+++ b/drivers/serial/serial_lpuart.c
@@ -17,6 +17,10 @@
#define US1_OR (1 << 3)
#define UC2_TE (1 << 3)
#define UC2_RE (1 << 2)
+#define CFIFO_TXFLUSH (1 << 7)
+#define CFIFO_RXFLUSH (1 << 6)
+#define SFIFO_RXOF (1 << 2)
+#define SFIFO_RXUF (1 << 0)
DECLARE_GLOBAL_DATA_PTR;
@@ -85,6 +89,12 @@
__raw_writeb(0, &base->umodem);
__raw_writeb(0, &base->uc1);
+ /* Disable FIFO and flush buffer */
+ __raw_writeb(0x0, &base->upfifo);
+ __raw_writeb(0x0, &base->utwfifo);
+ __raw_writeb(0x1, &base->urwfifo);
+ __raw_writeb(CFIFO_TXFLUSH | CFIFO_RXFLUSH, &base->ucfifo);
+
/* provide data bits, parity, stop bit, etc */
serial_setbrg();