From: Ilpo Järvinen ilpo.jarvinen@linux.intel.com
[ Upstream commit 197eb5c416ff0e52d152e6ff59b4e759d2f3e10d ]
dw8250_handle_irq() reads LSR under a few conditions, convert both to use serial_lsr_in() in order to preserve LSR flags properly across reads.
Fixes: 424d79183af0 ("serial: 8250_dw: Avoid "too much work" from bogus rx timeout interrupt") Fixes: aa63d786cea2 ("serial: 8250: dw: Add support for DMA flow controlling devices") Cc: Douglas Anderson dianders@chromium.org Cc: Phil Edworthy phil.edworthy@renesas.com Cc: Miquel Raynal miquel.raynal@bootlin.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Link: https://lore.kernel.org/r/20220608095431.18376-6-ilpo.jarvinen@linux.intel.c... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/8250/8250_dw.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index bb6aca07ab56..7e05b431a314 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -253,7 +253,7 @@ static int dw8250_handle_irq(struct uart_port *p) */ if (!up->dma && rx_timeout) { spin_lock_irqsave(&p->lock, flags); - status = p->serial_in(p, UART_LSR); + status = serial_lsr_in(up);
if (!(status & (UART_LSR_DR | UART_LSR_BI))) (void) p->serial_in(p, UART_RX); @@ -263,7 +263,7 @@ static int dw8250_handle_irq(struct uart_port *p)
/* Manually stop the Rx DMA transfer when acting as flow controller */ if (quirks & DW_UART_QUIRK_IS_DMA_FC && up->dma && up->dma->rx_running && rx_timeout) { - status = p->serial_in(p, UART_LSR); + status = serial_lsr_in(up); if (status & (UART_LSR_DR | UART_LSR_BI)) { dw8250_writel_ext(p, RZN1_UART_RDMACR, 0); dw8250_writel_ext(p, DW_UART_DMASA, 1);