Commit 75f54acc authored Jan 20, 2017 by Vignesh R Committed by Greg Kroah-Hartman Jan 20, 2017

serial: 8250_omap: pause DMA only if DMA transfer in progress

It is possible that DMA transfer is already complete but, completion
handler is yet to be called, when dmaengine_pause() is called in case of
error condition(like break/rx timeout). This leads to dmaengine_pause()
API to return EINVAL (as descriptor is already NULL) causing
rx_dma_broken flag to be set and effectively disabling RX DMA.
Fix this by calling dmaengine_pause() only when transfer is in progress.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent c92d781f

drivers/tty/serial/8250/8250_omap.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -790,6 +790,7 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
		{
		struct omap8250_priv *priv = p->port.private_data;
		struct uart_8250_dma *dma = p->dma;
		struct dma_tx_state state;
		unsigned long flags;
		int ret;

		@@ -800,10 +801,12 @@ static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
		return;
		}

		ret = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
		if (ret == DMA_IN_PROGRESS) {
		ret = dmaengine_pause(dma->rxchan);
		if (WARN_ON_ONCE(ret))
		priv->rx_dma_broken = true;

		}
		spin_unlock_irqrestore(&priv->rx_dma_lock, flags);

		__dma_rx_do_complete(p);