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Commit e7327c09 authored by Muhammad Hamza Farooq's avatar Muhammad Hamza Farooq Committed by Greg Kroah-Hartman
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serial: sh-sci: Pause DMA engine and get DMA status again 



Occasionally, DMA transaction completes _after_ DMA engine is stopped.
Verify if the transaction has not finished before forcing the engine to
stop and push the data

Signed-off-by: default avatarMuhammad Hamza Farooq <mfarooq@visteon.com>
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3b963042

drivers/tty/serial/sh-sci.c

+16 −0
Original line number Diff line number Diff line
@@ -1277,6 +1277,7 @@ static bool filter(struct dma_chan *chan, void *slave) 
static void rx_timer_fn(unsigned long arg)

{

	struct sci_port *s = (struct sci_port *)arg;

	struct dma_chan *chan = s->chan_rx;

	struct uart_port *port = &s->port;

	struct dma_tx_state state;

	enum dma_status status;
@@ -1305,6 +1306,21 @@ static void rx_timer_fn(unsigned long arg) 
		return;

	}



	dmaengine_pause(chan);



	/*

	 * sometimes DMA transfer doesn't stop even if it is stopped and

	 * data keeps on coming until transaction is complete so check

	 * for DMA_COMPLETE again

	 * Let packet complete handler take care of the packet

	 */

	status = dmaengine_tx_status(s->chan_rx, s->active_rx, &state);

	if (status == DMA_COMPLETE) {

		spin_unlock_irqrestore(&port->lock, flags);

		dev_dbg(port->dev, "Transaction complete after DMA engine was stopped");

		return;

	}



	/* Handle incomplete DMA receive */

	dmaengine_terminate_all(s->chan_rx);

	read = sg_dma_len(&s->sg_rx[active]) - state.residue;