lkml.org 
[lkml]   [2014]   [Jul]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[RFC PATCH 4/7] serial: 8250_dma: enqueue RX dma again on completion.
    Date
    The omap needs a DMA request pending right away. If it is enqueued once
    the bytes are in the FIFO then nothing will happen and the FIFO will be
    later purged via RX-timeout interrupt.
    This patch requeues RX-DMA request on completion but not if it was
    canceled due to the RX-timeout.

    Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    ---
    drivers/tty/serial/8250/8250_core.c | 3 +++
    drivers/tty/serial/8250/8250_dma.c | 12 +++++++++---
    2 files changed, 12 insertions(+), 3 deletions(-)

    diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
    index 7a33c30..098ff02 100644
    --- a/drivers/tty/serial/8250/8250_core.c
    +++ b/drivers/tty/serial/8250/8250_core.c
    @@ -1556,6 +1556,9 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)

    if (!up->dma || dma_err)
    status = serial8250_rx_chars(up, status);
    +
    + if (dma_err == -ETIMEDOUT && port->type == PORT_OMAP_16750)
    + serial8250_rx_dma(up, 0);
    }
    serial8250_modem_status(up);
    if (!up->dma && (status & UART_LSR_THRE))
    diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
    index f9ef69f..acb0a87 100644
    --- a/drivers/tty/serial/8250/8250_dma.c
    +++ b/drivers/tty/serial/8250/8250_dma.c
    @@ -49,9 +49,8 @@ static void __dma_tx_complete(void *param)
    spin_unlock_irqrestore(&p->port.lock, flags);
    }

    -static void __dma_rx_complete(void *param)
    +static void __dma_rx_do_complete(struct uart_8250_port *p, bool timeout)
    {
    - struct uart_8250_port *p = param;
    struct uart_8250_dma *dma = p->dma;
    struct tty_port *tty_port = &p->port.state->port;
    struct dma_tx_state state;
    @@ -67,10 +66,17 @@ static void __dma_rx_complete(void *param)

    tty_insert_flip_string(tty_port, dma->rx_buf, count);
    p->port.icount.rx += count;
    + if (!timeout && p->port.type == PORT_OMAP_16750)
    + serial8250_rx_dma(p, 0);

    tty_flip_buffer_push(tty_port);
    }

    +static void __dma_rx_complete(void *param)
    +{
    + __dma_rx_do_complete(param, false);
    +}
    +
    int serial8250_tx_dma(struct uart_8250_port *p)
    {
    struct uart_8250_dma *dma = p->dma;
    @@ -126,7 +132,7 @@ int serial8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
    */
    if (dma_status == DMA_IN_PROGRESS) {
    dmaengine_pause(dma->rxchan);
    - __dma_rx_complete(p);
    + __dma_rx_do_complete(p, true);
    }
    return -ETIMEDOUT;
    default:
    --
    2.0.1


    \
     
     \ /
      Last update: 2014-07-29 21:41    [W:4.236 / U:0.352 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site