target/linux/imx6/patches-4.14/210-disable-uart-dma.patch

   1 Based on following upstream patch by Tim Harvey (Gateworks):
   2
   3 https://github.com/Gateworks/openwrt/commit/80a01b6582f94c4547f39d3a25e0a1e9b6eb9877
   4
   5 TX complete DMA messages are getting missed.
   6 This is also currently an issue in mainline.
   7 For now we will disable DMA in serial/imx.c.
   8
   9 This resolves an issue encountered with RS485 transmit.
  10
  11 --- a/drivers/tty/serial/imx.c
  12 +++ b/drivers/tty/serial/imx.c
  13 @@ -1268,10 +1268,6 @@ static int imx_startup(struct uart_port
  14
  15         writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
  16
  17 -       /* Can we enable the DMA support? */
  18 -       if (!uart_console(port) && !sport->dma_is_inited)
  19 -               imx_uart_dma_init(sport);
  20 -
  21         spin_lock_irqsave(&sport->port.lock, flags);
  22         /* Reset fifo's and state machines */
  23         i = 100;