MIPS: Loongson: Cleanup the serial port support

To share the same kernel image amon different machines we have added the
machtype command line support.

In the old serial port implementation the UART base address is hardcoded as
a macro in machine.h which breaks with machtype, so change that to discover
the address dynamically.  Also move the initialization of the UART base
address to uart_base.c to avoid remapping twice for early_printk.c and
serial.c.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/581/
Patchwork: http://patchwork.linux-mips.org/patch/682/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/loongson/common/uart_base.c

@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2009 Lemote Inc.
+ * Author: Wu Zhangjin, wuzj@lemote.com
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <asm/bootinfo.h>
+
+#include <loongson.h>
+
+unsigned long __maybe_unused _loongson_uart_base;
+EXPORT_SYMBOL(_loongson_uart_base);
+
+unsigned long __maybe_unused uart8250_base[] = {
+	[MACH_LOONGSON_UNKNOWN]	0,
+	[MACH_LEMOTE_FL2E]	(LOONGSON_PCIIO_BASE + 0x3f8),
+	[MACH_LEMOTE_FL2F]	(LOONGSON_PCIIO_BASE + 0x2f8),
+	[MACH_LEMOTE_ML2F7]	(LOONGSON_LIO1_BASE + 0x3f8),
+	[MACH_LEMOTE_YL2F89]	(LOONGSON_LIO1_BASE + 0x3f8),
+	[MACH_DEXXON_GDIUM2F10]	(LOONGSON_LIO1_BASE + 0x3f8),
+	[MACH_LOONGSON_END]	0,
+};
+EXPORT_SYMBOL(uart8250_base);
+
+void __maybe_unused prom_init_uart_base(void)
+{
+	_loongson_uart_base =
+		(unsigned long)ioremap_nocache(uart8250_base[mips_machtype], 8);
+}