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

From: Sherry Sun
Date: Mon Nov 28 2022 - 00:04:04 EST


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@xxxxxxx>
---
drivers/tty/serial/fsl_lpuart.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 8918e08bb19e..bb12b328e224 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1682,6 +1682,16 @@ 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;
@@ -1706,11 +1716,12 @@ 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);
--
2.17.1