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Commit 6e14f7c1 authored by Soren Brinkmann's avatar Soren Brinkmann Committed by Greg Kroah-Hartman
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tty: xuartps: Improve startup function 



The startup function is supposed to initialize the UART for receiving.
Hence, don't enable the TX part. Also, protect HW accesses with the port
lock.

Signed-off-by: default avatarSoren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent aea8f3dd

drivers/tty/serial/xilinx_uartps.c

+12 −8
Original line number Diff line number Diff line
@@ -758,6 +758,7 @@ static void cdns_uart_set_termios(struct uart_port *port, 
 */

static int cdns_uart_startup(struct uart_port *port)

{

	unsigned long flags;

	unsigned int retval = 0, status = 0;



	retval = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME,
@@ -765,6 +766,8 @@ static int cdns_uart_startup(struct uart_port *port) 
	if (retval)

		return retval;



	spin_lock_irqsave(&port->lock, flags);



	/* Disable the TX and RX */

	writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,

			port->membase + CDNS_UART_CR_OFFSET);
@@ -775,15 +778,14 @@ static int cdns_uart_startup(struct uart_port *port) 
	writel(CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST,

			port->membase + CDNS_UART_CR_OFFSET);



	status = readl(port->membase + CDNS_UART_CR_OFFSET);



	/* Clear the RX disable and TX disable bits and then set the TX enable

	 * bit and RX enable bit to enable the transmitter and receiver.

	/*

	 * Clear the RX disable bit and then set the RX enable bit to enable

	 * the receiver.

	 */

	writel((status & ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS))

			| (CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN |

			CDNS_UART_CR_STOPBRK),

			port->membase + CDNS_UART_CR_OFFSET);

	status = readl(port->membase + CDNS_UART_CR_OFFSET);

	status &= CDNS_UART_CR_RX_DIS;

	status |= CDNS_UART_CR_RX_EN;

	writel(status, port->membase + CDNS_UART_CR_OFFSET);



	/* Set the Mode Register with normal mode,8 data bits,1 stop bit,

	 * no parity.
@@ -814,6 +816,8 @@ static int cdns_uart_startup(struct uart_port *port) 
		CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_TOUT,

		port->membase + CDNS_UART_IER_OFFSET);



	spin_unlock_irqrestore(&port->lock, flags);



	return retval;

}