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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: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Soren Brinkmann 2015-12-26 02:43:53 -08:00 committed by Greg Kroah-Hartman
parent aea8f3ddcf
commit 6e14f7c1f2
1 changed files with 12 additions and 8 deletions
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20
drivers/tty/serial/xilinx_uartps.c
View File

@ -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;
}