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From: Vignesh Raghavendra <vigneshr@ti.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>,
	<linux-serial@vger.kernel.org>, <linux-omap@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>
Subject: [PATCH 5/6] serial: 8250: 8250_omap: Work around errata causing spurious IRQs with DMA
Date: Thu, 19 Mar 2020 16:33:43 +0530	[thread overview]
Message-ID: <20200319110344.21348-6-vigneshr@ti.com> (raw)
In-Reply-To: <20200319110344.21348-1-vigneshr@ti.com>

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 <vigneshr@ti.com>
---
 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 207759dfbff2..92508aaa961c 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);
-- 
2.25.2


  parent reply	other threads:[~2020-03-19 11:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-19 11:03 [PATCH 0/6] 8250_omap: Add DMA for AM654/J721e type UARTs Vignesh Raghavendra
2020-03-19 11:03 ` [PATCH 1/6] serial: 8250: 8250_omap: Terminate DMA before pushing data on RX timeout Vignesh Raghavendra
2020-03-19 11:03 ` [PATCH 2/6] serial: 8250: 8250_omap: Account for data in flight during DMA teardown Vignesh Raghavendra
2020-03-19 11:03 ` [PATCH 3/6] serial: 8250: 8250_omap: Move locking out from __dma_rx_do_complete() Vignesh Raghavendra
2020-03-19 11:03 ` [PATCH 4/6] serial: 8250: 8250_omap: Extend driver data to pass FIFO trigger info Vignesh Raghavendra
2020-03-19 11:03 ` Vignesh Raghavendra [this message]
2020-03-19 11:03 ` [PATCH 6/6] serial: 8250: 8250_omap: Add DMA support for UARTs on K3 SoCs Vignesh Raghavendra

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