From 6e14f7c1f2c2e8d783b4bc50e7ac31b468910698 Mon Sep 17 00:00:00 2001 From: Soren Brinkmann Date: Sat, 26 Dec 2015 02:43:53 -0800 Subject: [PATCH] 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 Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/xilinx_uartps.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index ef114d7a0623..6ffd3bbe3e18 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -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; } -- 2.30.2