tty: serial: fsl_lpuart: disable Rx/Tx DMA in lpuart32_shutdown()

UARTBAUD_RDMAE and UARTBAUD_TDMAE are enabled in lpuart32_startup(), but
lpuart32_shutdown() not disable them, only free the dma ring buffer and
release the dma channels, so here disable the Rx/Tx DMA first in
lpuart32_shutdown().

Fixes: 42b68768e51b ("serial: fsl_lpuart: DMA support for 32-bit variant")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221125101953.18753-3-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 9b8d322..88697dd 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1799,6 +1799,11 @@ static void lpuart32_shutdown(struct uart_port *port)
 
        spin_lock_irqsave(&port->lock, flags);
 
+       /* disable Rx/Tx DMA */
+       temp = lpuart32_read(port, UARTBAUD);
+       temp &= ~(UARTBAUD_TDMAE | UARTBAUD_RDMAE);
+       lpuart32_write(port, temp, UARTBAUD);
+
        /* disable Rx/Tx and interrupts */
        temp = lpuart32_read(port, UARTCTRL);
        temp &= ~(UARTCTRL_TE | UARTCTRL_RE | UARTCTRL_ILIE |