Revert "serial: imx: initialized DMA w/o HW flow enabled"

This reverts commit 068500e08dc87ea9a453cc4a500cf3ab28d0f936.

According to some tests, SDMA support is broken at least for i.MX6 without
HW flow control. Different forms of data-corruption appear either with
the ROM firmware for the SDMA controller as well as when loading Freescale
provided SDMA firmware versions 1.1 or 3.1.

Signed-off-by: David Jander <david@protonic.nl>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 2c90dc3..54fdc78 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -1121,11 +1121,6 @@ static int imx_startup(struct uart_port *port)
 
        writel(temp & ~UCR4_DREN, sport->port.membase + UCR4);
 
-       /* Can we enable the DMA support? */
-       if (is_imx6q_uart(sport) && !uart_console(port) &&
-           !sport->dma_is_inited)
-               imx_uart_dma_init(sport);
-
        spin_lock_irqsave(&sport->port.lock, flags);
        /* Reset fifo's and state machines */
        i = 100;
@@ -1143,9 +1138,6 @@ static int imx_startup(struct uart_port *port)
        writel(USR1_RTSD, sport->port.membase + USR1);
        writel(USR2_ORE, sport->port.membase + USR2);
 
-       if (sport->dma_is_inited && !sport->dma_is_enabled)
-               imx_enable_dma(sport);
-
        temp = readl(sport->port.membase + UCR1);
        temp |= UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN;
 
@@ -1316,6 +1308,11 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
                        } else {
                                ucr2 |= UCR2_CTSC;
                        }
+
+                       /* Can we enable the DMA support? */
+                       if (is_imx6q_uart(sport) && !uart_console(port)
+                               && !sport->dma_is_inited)
+                               imx_uart_dma_init(sport);
                } else {
                        termios->c_cflag &= ~CRTSCTS;
                }
@@ -1432,6 +1429,8 @@ imx_set_termios(struct uart_port *port, struct ktermios *termios,
        if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
                imx_enable_ms(&sport->port);
 
+       if (sport->dma_is_inited && !sport->dma_is_enabled)
+               imx_enable_dma(sport);
        spin_unlock_irqrestore(&sport->port.lock, flags);
 }