This patch adds an extra operation in ns16550.c to suuport MediaTek
SoCs as we have a highspeed register which influences the calcualtion
of the divisor.
Note that we don't support the baudrate greater than 115200 currently.
Signed-off-by: Ryder Lee <ryder....@mediatek.com>
Tested-by: Matthias Brugger <matthias....@gmail.com>
---
drivers/serial/ns16550.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
index f9041aa..f5410af 100644
--- a/drivers/serial/ns16550.c
+++ b/drivers/serial/ns16550.c
@@ -148,6 +148,13 @@ int ns16550_calc_divisor(NS16550_t port, int clock, int
baudrate)
static void NS16550_setbrg(NS16550_t com_port, int baud_divisor)
{
+#ifdef CONFIG_ARCH_MEDIATEK
+ /*
+ * MediaTek UARTs has an extra highspeed register.
+ * We need to clear it if baudrate <= 115200.
+ */
+ serial_out(0, &com_port->reg9);
+#endif
serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
serial_out(baud_divisor & 0xff, &com_port->dll);
serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
@@ -261,6 +268,9 @@ static inline void _debug_uart_init(void)
serial_dout(&com_port->mcr, UART_MCRVAL);
serial_dout(&com_port->fcr, UART_FCR_DEFVAL);
+#ifdef CONFIG_ARCH_MEDIATEK
+ serial_dout(&com_port->reg9, 0);
+#endif
serial_dout(&com_port->lcr, UART_LCR_BKSE | UART_LCRVAL);
serial_dout(&com_port->dll, baud_divisor & 0xff);
serial_dout(&com_port->dlm, (baud_divisor >> 8) & 0xff);
--
1.9.1
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