Current code resets the uart port only when it supports the irda mode.
In actually, we also need to reset the uart port in the non-irda mode.
A hang was caught in the following case:
UART A transmits data to the other end. But the transmission maybe
terminated. In some corner case, the TX FIFO maybe not empty.
The kernel will hang at the imx_set_termios():
............................................................
while (!(readl(sport->port.membase + USR2) & USR2_TXDC))
barrier();
............................................................
This patch resets the uart port all the time in the imx_startup().
And fix the hang.
Signed-off-by: Huang Shijie <b32...@freescale.com>
---
drivers/tty/serial/imx.c | 22 ++++++++++------------
1 files changed, 10 insertions(+), 12 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 3b6c1a2..64901d0 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1070,7 +1070,7 @@ static void imx_disable_dma(struct imx_port *sport)
static int imx_startup(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
- int retval;
+ int retval, i;
unsigned long flags, temp;
retval = clk_prepare_enable(sport->clk_per);
@@ -1098,17 +1098,15 @@ static int imx_startup(struct uart_port *port)
writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
- if (USE_IRDA(sport)) {
- /* reset fifo's and state machines */
- int i = 100;
- temp = readl(sport->port.membase + UCR2);
- temp &= ~UCR2_SRST;
- writel(temp, sport->port.membase + UCR2);
- while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) &&
- (--i > 0)) {
- udelay(1);
- }
- }
+ /* Reset fifo's and state machines */
+ i = 100;
+
+ temp = readl(sport->port.membase + UCR2);
+ temp &= ~UCR2_SRST;
+ writel(temp, sport->port.membase + UCR2);
+
+ while (!(readl(sport->port.membase + UCR2) & UCR2_SRST) && (--i > 0))
+ udelay(1);
/*
* Allocate the IRQ(s) i.MX1 has three interrupts whereas later
--
1.7.8
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
