[PATCH 2/2] serial: imx: disable the receiver ready interrupt for imx_stop_rx
dirk.behme at de.bosch.com
Thu May 22 23:10:36 PDT 2014
On 23.05.2014 06:32, Huang Shijie wrote:
> This patch disables the receiver ready interrupt for imx_stop_rx.
> It reduces the interrupt numbers when the uart is going to close
> or suspend.
> Signed-off-by: Huang Shijie <b32955 at freescale.com>
> drivers/tty/serial/imx.c | 4 ++++
> 1 files changed, 4 insertions(+), 0 deletions(-)
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index ed6cdf7..6026101 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -440,6 +440,10 @@ static void imx_stop_rx(struct uart_port *port)
> temp = readl(sport->port.membase + UCR2);
> writel(temp & ~UCR2_RXEN, sport->port.membase + UCR2);
> + /* disable the `Receiver Ready Interrrupt` */
> + temp = readl(sport->port.membase + UCR1);
> + writel(temp & ~UCR1_RRDYEN, sport->port.membase + UCR1);
While this is about the RX irq, I've a slightly off-topic general
question regarding the usage of the *TX* irq in TX DMA mode:
It seems to me that the TX irq is kept enabled while the TX DMA is
running/enabled? Looking e.g. into the amba-pl011.c there it seems there
the logic is:
- Set up/start the TX DMA
- Disable the TX irq while the TX DMA is running (only waiting for the
TX DMA callback, then)
- Re-enable the TX irq in the TX DMA callback
- Let the TX irq fire, then. And if there are still data, set up the TX
This sounds quite more logical than the implementation in imx.c.
Or is my understanding completely wrong, here?
More information about the linux-arm-kernel