From: Fugang Duan fugang.duan@nxp.com
stable inclusion from stable-v5.10.94 commit f0653cd4da669cbcddd81f8edd9f542805252691 bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ 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@nxp.com Signed-off-by: Sherry Sun sherry.sun@nxp.com Link: https://lore.kernel.org/r/20211125020349.4980-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- 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 e40f647985b6..a95ec61f8266 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -508,18 +508,21 @@ 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); @@ -1576,7 +1579,7 @@ 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);