serial: mvebu-uart: add soft reset at probe

The existing UART driver relies on the bootloader to initialize the
port(s). However, the secondary uart port may not be initialized
properly in early boot stage. This patch adds the UART soft reset when
probing, for all ports.

Signed-off-by: Allen Yan <yanwei@marvell.com>
Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
Reviewed-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 900fe85796d689683e4853da46334254da34e31f..e233f464d55a792c67009c40cb65ee24b359e0ca 100644 (file)
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -660,6 +660,11 @@ static int mvebu_uart_probe(struct platform_device *pdev)
        port->private_data = mvuart;
        platform_set_drvdata(pdev, mvuart);
 
+       /* UART Soft Reset*/
+       writel(CTRL_SOFT_RST, port->membase + UART_CTRL(port));
+       udelay(1);
+       writel(0, port->membase + UART_CTRL(port));
+
        ret = uart_add_one_port(&mvebu_uart_driver, port);
        if (ret)
                return ret;