Commit 4e4e6602 authored Oct 13, 2010 by Volker Ernst Committed by Greg Kroah-Hartman Oct 22, 2010

serial/imx: check that the buffer is non-empty before sending it out



The .start_tx callback (imx_start_tx here) isn't only called when the
buffer is non-empty.  E.g. after resume or when handshaking is enabled
and the other side starts to signal being ready.

So check for an empty puffer already before sending the first character.
This prevents sending out stale (or uninitialised) data.

Signed-off-by: Volker Ernst <volker.ernst@txtr.com>
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Andy Green <andy@warmcat.com>
[ukl: reword commit log, put check in while condition]
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent e5586ecc

drivers/serial/imx.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -327,14 +327,13 @@ static inline void imx_transmit_buffer(struct imx_port *sport)
		{
		struct circ_buf *xmit = &sport->port.state->xmit;

		while (!(readl(sport->port.membase + UTS) & UTS_TXFULL)) {
		while (!uart_circ_empty(xmit) &&
		!(readl(sport->port.membase + UTS) & UTS_TXFULL)) {
		/* send xmit->buf[xmit->tail]
		* out the port here */
		writel(xmit->buf[xmit->tail], sport->port.membase + URTX0);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		sport->port.icount.tx++;
		if (uart_circ_empty(xmit))
		break;
		}

		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)