On Fri, May 24, 2019 at 1:22 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, May 21, 2019 at 04:33:38PM +0530, shubhrajyoti.datta@xxxxxxxxx wrote:
> > From: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
> >
> > In case the cable is not connected then the target gets into
> > a infinite wait for tx empty.
> > Add a timeout to the tx empty wait.
> >
> > Reported-by: Jean-Francois Dagenais <jeff.dagenais@xxxxxxxxx>
> > Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
> > ---
> > 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 8850790..dc86511 100644
> > --- a/drivers/tty/serial/xilinx_uartps.c
> > +++ b/drivers/tty/serial/xilinx_uartps.c
> > @@ -26,12 +26,14 @@
> > #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"
> > #define CDNS_UART_MAJOR 0 /* use dynamic node allocation */
> > #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;
> > @@ -688,14 +690,18 @@ 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;
> >
> > /* 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_info(port->dev, "timed out waiting for tx empty");
> > + return;
>
> Also, shouldn't this be an error? Why not tell the caller something
> went wrong?
Will do in next version
>
> thanks,
>
> greg k-h
