On Sun, 9 Sep 2012 21:14:04 -0700
Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> wrote:
> It's all pretty straightforward, except for TXIM interrupt. The interrupt
> has meaning "ready to transmit", so it's almost always raised, and the
> only way to silence it is to mask it. But that's OK, ops->start_tx will
> unmask it.
>
> Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
> ---
> drivers/tty/serial/amba-pl011.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index 88e2df2..7522d97 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -1308,6 +1308,18 @@ static void pl011_put_poll_char(struct uart_port *port,
> writew(ch, uap->port.membase + UART01x_DR);
> }
>
> +static void pl011_clear_irqs(struct uart_port *port)
> +{
> + struct uart_amba_port *uap = (struct uart_amba_port *)port;
> + unsigned char __iomem *regs = uap->port.membase;
> +
> + writew(readw(regs + UART011_MIS), regs + UART011_ICR);
> + /*
> + * There is no way to clear TXIM, this is "ready to transmit IRQ", so
> + * we simply mask it. ops->start_tx will unmask it.
> + */
Not if you race here with the transmit start it won't.
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