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

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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>
This commit is contained in:
Vignesh R 2017-01-20 13:46:52 +05:30 committed by Greg Kroah-Hartman
parent c92d781f1a
commit 75f54acc08
1 changed files with 7 additions and 4 deletions
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11
drivers/tty/serial/8250/8250_omap.c
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@ -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_pause(dma->rxchan);
if (WARN_ON_ONCE(ret))
priv->rx_dma_broken = true;
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);