From: Fugang Duan <fugang.duan@xxxxxxx> [ Upstream commit 028e083832b06fdeeb290e1e57dc1f6702c4c215 ] The UCR4_OREN should be disabled before disabling the uart receiver in .stop_rx() instead of in the .shutdown(). Otherwise, if we have the overrun error during the receiver disable process, the overrun interrupt will keep trigging until we disable the OREN interrupt in the .shutdown(), because the ORE status can only be cleared when read the rx FIFO or reset the controller. Although the called time between the receiver disable and OREN disable in .shutdown() is very short, there is still the risk of endless interrupt during this short period of time. So here change to disable OREN before the receiver been disabled in .stop_rx(). Signed-off-by: Fugang Duan <fugang.duan@xxxxxxx> Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx> Link: https://lore.kernel.org/r/20211125020349.4980-1-sherry.sun@xxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/tty/serial/imx.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 90f82e6c54e46..6f7f382d0b1fa 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); ucr2 &= ~UCR2_RXEN; imx_uart_writel(sport, ucr2, UCR2); @@ -1544,7 +1547,7 @@ static void imx_uart_shutdown(struct uart_port *port) imx_uart_writel(sport, ucr1, UCR1); ucr4 = imx_uart_readl(sport, UCR4); - ucr4 &= ~(UCR4_OREN | UCR4_TCEN); + ucr4 &= ~UCR4_TCEN; imx_uart_writel(sport, ucr4, UCR4); spin_unlock_irqrestore(&sport->port.lock, flags); -- 2.34.1
