From c6689dfd877991f5415628c3ad04d4df9c1cf646 Mon Sep 17 00:00:00 2001 From: Vignesh Raghavendra Date: Thu, 19 Mar 2020 16:33:43 +0530 Subject: [PATCH] serial: 8250: 8250_omap: Work around errata causing spurious IRQs with DMA As per Advisory 27 of AM437x Silicon errata document, Spurious UART interrupts may occur when DMA mode (FCR.DMA_MODE) is enabled. The Interrupt Controller flags that a UART interrupt has occurred; however, the associated IT_PENDING bit remains set to 1, indicating that no interrupt is pending. Acknowledge the spurious interrupts for every occurrence as workaround. Errata is applicable to all TI SoCs with this IP. Signed-off-by: Vignesh Raghavendra Link: https://lore.kernel.org/r/20200319110344.21348-6-vigneshr@ti.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_omap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index fb709e08fc66..9293a3e94f07 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -1051,7 +1051,7 @@ static int omap_8250_dma_handle_irq(struct uart_port *port) iir = serial_port_in(port, UART_IIR); if (iir & UART_IIR_NO_INT) { serial8250_rpm_put(up); - return 0; + return IRQ_HANDLED; } spin_lock_irqsave(&port->lock, flags);