From: Sherry Sun <sherry.sun@nxp.com>

Date: Mon, 30 Jan 2023 14:44:46 +0800

Subject: [PATCH] tty: serial: fsl_lpuart: Fix the wrong RXWATER setting for rx

 dma case

References: bsc#1012628

Patch-mainline: 6.2.3

Git-commit: 9ad9df8447547febe9dd09b040f4528a09e495f0

[ Upstream commit 9ad9df8447547febe9dd09b040f4528a09e495f0 ]

The RXWATER value must be greater than 0 according to the LPUART

reference manual. And when the number of datawords in the receive

FIFO is greater than RXWATER, an interrupt or a DMA request is

generated, so no need to set the different value for lpuart interrupt

case and dma case. Here delete the wrong RXWATER setting for dma case

directly.

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/20230130064449.9564-4-sherry.sun@nxp.com

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Sasha Levin <sashal@kernel.org>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 drivers/tty/serial/fsl_lpuart.c | 6 ------

 1 file changed, 6 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c

index 986ec832..f34fabdc 100644

--- a/drivers/tty/serial/fsl_lpuart.c

+++ b/drivers/tty/serial/fsl_lpuart.c

@@ -1683,12 +1683,6 @@ static void lpuart32_configure(struct lpuart_port *sport)

 {

 	unsigned long temp;

-	if (sport->lpuart_dma_rx_use) {

-		/* RXWATER must be 0 */

-		temp = lpuart32_read(&sport->port, UARTWATER);

-		temp &= ~(UARTWATER_WATER_MASK << UARTWATER_RXWATER_OFF);

-		lpuart32_write(&sport->port, temp, UARTWATER);

-	}

 	temp = lpuart32_read(&sport->port, UARTCTRL);

 	if (!sport->lpuart_dma_rx_use)

 		temp |= UARTCTRL_RIE;

-- 

2.35.3