Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/arm/mach-lpc32xx/serial.c b/arch/arm/mach-lpc32xx/serial.c
index 1931229..3e765c4 100644
--- a/arch/arm/mach-lpc32xx/serial.c
+++ b/arch/arm/mach-lpc32xx/serial.c
@@ -1,19 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * arch/arm/mach-lpc32xx/serial.c
  *
  * Author: Kevin Wells <kevin.wells@nxp.com>
  *
  * Copyright (C) 2010 NXP Semiconductors
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
  */
 
 #include <linux/kernel.h>
@@ -25,8 +16,7 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 
-#include <mach/hardware.h>
-#include <mach/platform.h>
+#include "lpc32xx.h"
 #include "common.h"
 
 #define LPC32XX_SUART_FIFO_SIZE	64
@@ -69,6 +59,36 @@
 	},
 };
 
+/* LPC3250 Errata HSUART.1: Hang workaround via loopback mode on inactivity */
+void lpc32xx_loopback_set(resource_size_t mapbase, int state)
+{
+	int bit;
+	u32 tmp;
+
+	switch (mapbase) {
+	case LPC32XX_HS_UART1_BASE:
+		bit = 0;
+		break;
+	case LPC32XX_HS_UART2_BASE:
+		bit = 1;
+		break;
+	case LPC32XX_HS_UART7_BASE:
+		bit = 6;
+		break;
+	default:
+		WARN(1, "lpc32xx_hs: Warning: Unknown port at %08x\n", mapbase);
+		return;
+	}
+
+	tmp = readl(LPC32XX_UARTCTL_CLOOP);
+	if (state)
+		tmp |= (1 << bit);
+	else
+		tmp &= ~(1 << bit);
+	writel(tmp, LPC32XX_UARTCTL_CLOOP);
+}
+EXPORT_SYMBOL_GPL(lpc32xx_loopback_set);
+
 void __init lpc32xx_serial_init(void)
 {
 	u32 tmp, clkmodes = 0;