Commit 5aabd3b0 authored Aug 28, 2017 by Ian Jamison Committed by Greg Kroah-Hartman Aug 28, 2017

serial: imx: Avoid post-PIO cleanup if TX DMA is started

The imx_transmit_buffer function should return if TX DMA has already
been started and not just skip over the buffer PIO write loop. (Which
did fix the initial problem, but could have unintentional side-effects)

Tested on an i.MX6Q board with half-duplex RS-485 and with RS-232.

Cc: Clemens Gruber <clemens.gruber@pqgruber.com>
Cc: Uwe-Kleine König <u.kleine-koenig@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Fixes: 514ab34d ("serial: imx: Prevent TX buffer PIO write when a DMA has been started")
Signed-off-by: Ian Jamison <ian.dev@arkver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 81b289cc

drivers/tty/serial/imx.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -457,7 +457,10 @@ static inline void imx_transmit_buffer(struct imx_port *sport)
		}
		}

		while (!uart_circ_empty(xmit) && !sport->dma_is_txing &&
		if (sport->dma_is_txing)
		return;

		while (!uart_circ_empty(xmit) &&
		!(readl(sport->port.membase + uts_reg(sport)) & UTS_TXFULL)) {
		/* send xmit->buf[xmit->tail]
		* out the port here */