v4.19.13 snapshot.
diff --git a/arch/mips/loongson64/common/serial.c b/arch/mips/loongson64/common/serial.c
new file mode 100644
index 0000000..ffefc1c
--- /dev/null
+++ b/arch/mips/loongson64/common/serial.c
@@ -0,0 +1,117 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2007 Ralf Baechle (ralf@linux-mips.org)
+ *
+ * Copyright (C) 2009 Lemote, Inc.
+ * Author: Yan hua (yanhua@lemote.com)
+ * Author: Wu Zhangjin (wuzhangjin@gmail.com)
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/serial_8250.h>
+
+#include <asm/bootinfo.h>
+
+#include <loongson.h>
+#include <machine.h>
+
+#define PORT(int, clk)			\
+{								\
+	.irq		= int,					\
+	.uartclk	= clk,					\
+	.iotype		= UPIO_PORT,				\
+	.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,	\
+	.regshift	= 0,					\
+}
+
+#define PORT_M(int, clk)				\
+{								\
+	.irq		= MIPS_CPU_IRQ_BASE + (int),		\
+	.uartclk	= clk,					\
+	.iotype		= UPIO_MEM,				\
+	.membase	= (void __iomem *)NULL,			\
+	.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,	\
+	.regshift	= 0,					\
+}
+
+static struct plat_serial8250_port uart8250_data[][MAX_UARTS + 1] = {
+	[MACH_LOONGSON_UNKNOWN]	= {},
+	[MACH_LEMOTE_FL2E]	= {PORT(4, 1843200), {} },
+	[MACH_LEMOTE_FL2F]	= {PORT(3, 1843200), {} },
+	[MACH_LEMOTE_ML2F7]	= {PORT_M(3, 3686400), {} },
+	[MACH_LEMOTE_YL2F89]	= {PORT_M(3, 3686400), {} },
+	[MACH_DEXXON_GDIUM2F10]	= {PORT_M(3, 3686400), {} },
+	[MACH_LEMOTE_NAS]	= {PORT_M(3, 3686400), {} },
+	[MACH_LEMOTE_LL2F]	= {PORT(3, 1843200), {} },
+	[MACH_LOONGSON_GENERIC]	= {PORT_M(2, 25000000), {} },
+	[MACH_LOONGSON_END]	= {},
+};
+
+static struct platform_device uart8250_device = {
+	.name = "serial8250",
+	.id = PLAT8250_DEV_PLATFORM,
+};
+
+static int __init serial_init(void)
+{
+	int i;
+	unsigned char iotype;
+
+	iotype = uart8250_data[mips_machtype][0].iotype;
+
+	if (UPIO_MEM == iotype) {
+		uart8250_data[mips_machtype][0].mapbase =
+			loongson_uart_base[0];
+		uart8250_data[mips_machtype][0].membase =
+			(void __iomem *)_loongson_uart_base[0];
+	}
+	else if (UPIO_PORT == iotype)
+		uart8250_data[mips_machtype][0].iobase =
+			loongson_uart_base[0] - LOONGSON_PCIIO_BASE;
+
+	if (loongson_sysconf.uarts[0].uartclk)
+		uart8250_data[mips_machtype][0].uartclk =
+			loongson_sysconf.uarts[0].uartclk;
+
+	for (i = 1; i < loongson_sysconf.nr_uarts; i++) {
+		iotype = loongson_sysconf.uarts[i].iotype;
+		uart8250_data[mips_machtype][i].iotype = iotype;
+		loongson_uart_base[i] = loongson_sysconf.uarts[i].uart_base;
+
+		if (UPIO_MEM == iotype) {
+			uart8250_data[mips_machtype][i].irq =
+				MIPS_CPU_IRQ_BASE + loongson_sysconf.uarts[i].int_offset;
+			uart8250_data[mips_machtype][i].mapbase =
+				loongson_uart_base[i];
+			uart8250_data[mips_machtype][i].membase =
+				ioremap_nocache(loongson_uart_base[i], 8);
+		} else if (UPIO_PORT == iotype) {
+			uart8250_data[mips_machtype][i].irq =
+				loongson_sysconf.uarts[i].int_offset;
+			uart8250_data[mips_machtype][i].iobase =
+				loongson_uart_base[i] - LOONGSON_PCIIO_BASE;
+		}
+
+		uart8250_data[mips_machtype][i].uartclk =
+			loongson_sysconf.uarts[i].uartclk;
+		uart8250_data[mips_machtype][i].flags =
+			UPF_BOOT_AUTOCONF | UPF_SKIP_TEST;
+	}
+
+	memset(&uart8250_data[mips_machtype][loongson_sysconf.nr_uarts],
+			0, sizeof(struct plat_serial8250_port));
+	uart8250_device.dev.platform_data = uart8250_data[mips_machtype];
+
+	return platform_device_register(&uart8250_device);
+}
+module_init(serial_init);
+
+static void __init serial_exit(void)
+{
+	platform_device_unregister(&uart8250_device);
+}
+module_exit(serial_exit);