From 68d12bb267da44f50167e64a95f1581cb729e5fc Mon Sep 17 00:00:00 2001
From: Helmut Grohne <h.grohne@intenta.de>
Date: Mon, 4 Jun 2018 12:22:05 +0200
Subject: [PATCH] serial: xuartps: fix typo in cdns_uart_startup
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Git-commit: 68d12bb267da44f50167e64a95f1581cb729e5fc
Patch-mainline: v4.19-rc1
References: bsc#1051510

The bit mask changes in commit 6e14f7c1f2c2 ("tty: xuartps: Improve
startup function") doesn't do what the commit message advertises. The
original behaviour was clearing the RX_DIS bit, but due to missing ~,
that bit is now the only bit kept.

Currently, the regression is harmless, because the previous write to the
control register sets it to TXRST | RXRST. Thus the RX_DIS bit is
previously cleared. The *RST bits are cleared by the hardware, so this
commit does not currently change behaviour, but makes future changes
less risky.

Link: https://www.spinics.net/lists/linux-serial/msg23157.html
Signed-off-by: Helmut Grohne <h.grohne@intenta.de>
Fixes: 6e14f7c1f2c2 ("tty: xuartps: Improve startup function")
Reviewed-by: Sören Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/tty/serial/xilinx_uartps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 8a3e34234e98..b0d2a6c5afcb 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -829,7 +829,7 @@ static int cdns_uart_startup(struct uart_port *port)
 	 * the receiver.
 	 */
 	status = readl(port->membase + CDNS_UART_CR);
-	status &= CDNS_UART_CR_RX_DIS;
+	status &= ~CDNS_UART_CR_RX_DIS;
 	status |= CDNS_UART_CR_RX_EN;
 	writel(status, port->membase + CDNS_UART_CR);
 
-- 
2.18.0