From: Shubhrajyoti Datta shubhrajyoti.datta@xilinx.com
commit 277375b864e8147975b064b513f491e2a910e66a upstream
In case the cable is not connected then the target gets into an infinite wait for tx empty. Add a timeout to the tx empty wait.
Reported-by: Jean-Francois Dagenais jeff.dagenais@gmail.com Signed-off-by: Shubhrajyoti Datta shubhrajyoti.datta@xilinx.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: stable stable@vger.kernel.org # 4.19 Signed-off-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/xilinx_uartps.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index 66d49d5118853..7cbee19ea93d5 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -26,6 +26,7 @@ #include <linux/of.h> #include <linux/module.h> #include <linux/pm_runtime.h> +#include <linux/iopoll.h>
#define CDNS_UART_TTY_NAME "ttyPS" #define CDNS_UART_NAME "xuartps" @@ -34,6 +35,7 @@ #define CDNS_UART_NR_PORTS 2 #define CDNS_UART_FIFO_SIZE 64 /* FIFO size */ #define CDNS_UART_REGISTER_SPACE 0x1000 +#define TX_TIMEOUT 500000
/* Rx Trigger level */ static int rx_trigger_level = 56; @@ -681,16 +683,20 @@ static void cdns_uart_set_termios(struct uart_port *port, unsigned int cval = 0; unsigned int baud, minbaud, maxbaud; unsigned long flags; - unsigned int ctrl_reg, mode_reg; + unsigned int ctrl_reg, mode_reg, val; + int err;
spin_lock_irqsave(&port->lock, flags);
/* Wait for the transmit FIFO to empty before making changes */ if (!(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_TX_DIS)) { - while (!(readl(port->membase + CDNS_UART_SR) & - CDNS_UART_SR_TXEMPTY)) { - cpu_relax(); + err = readl_poll_timeout(port->membase + CDNS_UART_SR, + val, (val & CDNS_UART_SR_TXEMPTY), + 1000, TX_TIMEOUT); + if (err) { + dev_err(port->dev, "timed out waiting for tx empty"); + return; } }