serial: 8250: 8250_omap: Account for data in flight during DMA teardown (4bcf59a5) · Commits · 戴 / test

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

+23 −4

Original line number	Diff line number	Diff line
		@@ -741,6 +741,8 @@ static void __dma_rx_do_complete(struct uart_8250_port *p)
		struct omap8250_priv *priv = p->port.private_data;
		struct uart_8250_dma *dma = p->dma;
		struct tty_port *tty_port = &p->port.state->port;
		struct dma_chan *rxchan = dma->rxchan;
		dma_cookie_t cookie;
		struct dma_tx_state state;
		int count;
		unsigned long flags;
		@@ -751,12 +753,29 @@ static void __dma_rx_do_complete(struct uart_8250_port *p)
		if (!dma->rx_running)
		goto unlock;

		cookie = dma->rx_cookie;
		dma->rx_running = 0;
		dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
		dmaengine_tx_status(rxchan, cookie, &state);

		count = dma->rx_size - state.residue;
		if (count < dma->rx_size)
		dmaengine_terminate_async(dma->rxchan);
		count = dma->rx_size - state.residue + state.in_flight_bytes;
		if (count < dma->rx_size) {
		dmaengine_terminate_async(rxchan);

		/*
		* Poll for teardown to complete which guarantees in
		* flight data is drained.
		*/
		if (state.in_flight_bytes) {
		int poll_count = 25;

		while (dmaengine_tx_status(rxchan, cookie, NULL) &&
		poll_count--)
		cpu_relax();

		if (!poll_count)
		dev_err(p->port.dev, "teardown incomplete\n");
		}
		}
		if (!count)
		goto unlock;
		ret = tty_insert_flip_string(tty_port, dma->rx_buf, count);