From: Matthias Schiffer Date: Thu, 28 May 2020 15:47:47 +0000 (+0200) Subject: tty: serial: imx: clear Ageing Timer Interrupt in handler X-Git-Tag: v5.15~3665^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d1d996afbd2bca3bf3c484fc1f7a738134d65207;p=platform%2Fkernel%2Flinux-starfive.git tty: serial: imx: clear Ageing Timer Interrupt in handler The AGTIM flag must be cleared explicitly, otherwise the IRQ handler will be called in an endless loop. Fortunately, this issue currently doesn't affect mainline kernels in practice, as the the RX FIFO trigger level is set to 1 in UFCR. When setting the trigger level to a higher number, the issue is trivially reproducible by any RX without DMA that doesn't fill the FIFO up to the configured level. Signed-off-by: Matthias Schiffer Link: https://lore.kernel.org/r/20200528154747.14201-1-matthias.schiffer@ew.tq-group.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 6b078e395931..1265e8d86d8a 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -909,6 +909,8 @@ static irqreturn_t imx_uart_int(int irq, void *dev_id) usr2 &= ~USR2_ORE; if (usr1 & (USR1_RRDY | USR1_AGTIM)) { + imx_uart_writel(sport, USR1_AGTIM, USR1); + __imx_uart_rxint(irq, dev_id); ret = IRQ_HANDLED; }