tty: serial: fsl_lpuart: don't enable receiver/transmitter before rx/tx dma ready

lpuart32_setup_watermark_enable() will configure the UART FIFO and
watermark, also enable the receiver and transmitter, this should be done
after the rx/tx dma steup ready.

Also add lpuart32_hw_disable() to make sure the receiver/transmitter and
interrupts are disabled during the dma steup.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20230130054107.9119-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 04fecff..eac5243 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1702,6 +1702,16 @@ static int lpuart_startup(struct uart_port *port)
        return 0;
 }
 
+static void lpuart32_hw_disable(struct lpuart_port *sport)
+{
+       unsigned long temp;
+
+       temp = lpuart32_read(&sport->port, UARTCTRL);
+       temp &= ~(UARTCTRL_RIE | UARTCTRL_ILIE | UARTCTRL_RE |
+                 UARTCTRL_TIE | UARTCTRL_TE);
+       lpuart32_write(&sport->port, temp, UARTCTRL);
+}
+
 static void lpuart32_configure(struct lpuart_port *sport)
 {
        unsigned long temp;
@@ -1726,11 +1736,12 @@ static void lpuart32_hw_setup(struct lpuart_port *sport)
 
        spin_lock_irqsave(&sport->port.lock, flags);
 
-       lpuart32_setup_watermark_enable(sport);
+       lpuart32_hw_disable(sport);
 
        lpuart_rx_dma_startup(sport);
        lpuart_tx_dma_startup(sport);
 
+       lpuart32_setup_watermark_enable(sport);
        lpuart32_configure(sport);
 
        spin_unlock_irqrestore(&sport->port.lock, flags);