Subject: [PATCH] serial: omap: fix the overrun case

From: [email-masked] (Kevin Hilman)
Date: Fri, 21 Sep 2012 07:18:54 -0700

Shubhrajyoti D <[email-masked]> writes:

> Overrun also causes an internal flag to be set, which disables further
> reception. Before the next frame can
> be received, the MPU must:
> ? Reset the RX FIFO.
> ? clear the internal flag.
>
> In the uart mode a dummy read is needed. Add the same.
>
> Signed-off-by: Shubhrajyoti D <[email-masked]>
> ---
> - functional testing on omap4sdp
> - Verified idle and suspend path hits off on beagle.

Tested-by: Kevin Hilman <[email-masked]>

This fixes the console hang I was seeing on 3530/Overo.

Thanks,

Kevin

>  drivers/tty/serial/omap-serial.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
> index a0d4460..bc22a2b 100644
> --- a/drivers/tty/serial/omap-serial.c
> +++ b/drivers/tty/serial/omap-serial.c
> @@ -334,6 +334,13 @@ static unsigned int check_modem_status(struct uart_omap_port *up)
>  static void serial_omap_rlsi(struct uart_omap_port *up, unsigned int lsr)
>  {
>  	unsigned int flag;
> +	unsigned char ch = 0;
> +
> +	if (!(lsr & UART_LSR_BRK_ERROR_BITS))
> +		return;
> +
> +	if (likely(lsr & UART_LSR_DR))
> +		ch = serial_in(up, UART_RX);
>  
>  	up->port.icount.rx++;
>  	flag = TTY_NORMAL;