diff options
Diffstat (limited to 'drivers/tty/serial/imx.c')
| -rw-r--r-- | drivers/tty/serial/imx.c | 25 |
1 files changed, 11 insertions, 14 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index db1987a0f513..dbee7ff2f8fd 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -927,23 +927,20 @@ static void dma_rx_callback(void *data) sport->port.icount.buf_overrun++; } tty_flip_buffer_push(port); + } + /* + * Restart RX DMA directly if more data is available in order to skip + * the roundtrip through the IRQ handler. If there is some data already + * in the FIFO, DMA needs to be restarted soon anyways. + * + * Otherwise stop the DMA and reactivate FIFO IRQs to restart DMA once + * data starts to arrive again. + */ + if (readl(sport->port.membase + USR2) & USR2_RDR) start_rx_dma(sport); - } else if (readl(sport->port.membase + USR2) & USR2_RDR) { - /* - * start rx_dma directly once data in RXFIFO, more efficient - * than before: - * 1. call imx_rx_dma_done to stop dma if no data received - * 2. wait next RDR interrupt to start dma transfer. - */ - start_rx_dma(sport); - } else { - /* - * stop dma to prevent too many IDLE event trigged if no data - * in RXFIFO - */ + else imx_rx_dma_done(sport); - } } static int start_rx_dma(struct imx_port *sport) |