Hello again, On Tue, Nov 23, 2021 at 08:51:22AM +0100, Uwe Kleine-König wrote: > On Tue, Nov 23, 2021 at 03:04:37PM +0800, Sherry Sun wrote: > > From: Fugang Duan > > > > Disable UCR4_OREN bit in .stop_rx() to avoid endless > > interrupt happen while tty port is closing. > > > > Signed-off-by: Fugang Duan > > Signed-off-by: Sherry Sun > > --- > > drivers/tty/serial/imx.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > > index fb75e3e0d828..9ecaf051249d 100644 > > --- a/drivers/tty/serial/imx.c > > +++ b/drivers/tty/serial/imx.c > > @@ -486,18 +486,21 @@ static void imx_uart_stop_tx(struct uart_port *port) > > static void imx_uart_stop_rx(struct uart_port *port) > > { > > struct imx_port *sport = (struct imx_port *)port; > > - u32 ucr1, ucr2; > > + u32 ucr1, ucr2, ucr4; > > > > ucr1 = imx_uart_readl(sport, UCR1); > > ucr2 = imx_uart_readl(sport, UCR2); > > + ucr4 = imx_uart_readl(sport, UCR4); > > > > if (sport->dma_is_enabled) { > > ucr1 &= ~(UCR1_RXDMAEN | UCR1_ATDMAEN); > > } else { > > ucr1 &= ~UCR1_RRDYEN; > > ucr2 &= ~UCR2_ATEN; > > + ucr4 &= ~UCR4_OREN; > > } > > imx_uart_writel(sport, ucr1, UCR1); > > + imx_uart_writel(sport, ucr4, UCR4); > > I don't understand this yet, but I guess this is just a matter of > improving the commit log. How does the endless irq happen? > > ... some time later after thinking and reading the driver source ... > > Hmm, when the OR event is triggered the handler does > > imx_uart_writel(sport, USR2_ORE, USR2); > > and so clears the event. I would expect that this should be good enough > to prevent an irq storm even if the receiver is disabled. Doesn't acking > work with the receiver disabled? One thing I forgot to mention: If imx_uart_stop_rx() now clears UCR4_OREN, clearing in imx_uart_shutdown() should probably be dropped. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |