1 files changed, 38 insertions, 0 deletions
diff --git a/arch/mips/loongson/common/early_printk.c b/arch/mips/loongson/common/early_printk.c
new file mode 100644
index 0000000..bc73edc
--- /dev/null
+++ b/arch/mips/loongson/common/early_printk.c
@@ -0,0 +1,38 @@
+/*  early printk support
+ *
+ *  Copyright (c) 2009 Philippe Vachon <philippe@cowpig.ca>
+ *  Copyright (C) 2009 Lemote Inc. & Insititute of Computing Technology
+ *  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/serial_reg.h>
+
+#include <loongson.h>
+#include <machine.h>
+
+#define PORT(base, offset) (u8 *)(base + offset)
+
+static inline unsigned int serial_in(phys_addr_t base, int offset)
+{
+	return readb(PORT(base, offset));
+}
+
+static inline void serial_out(phys_addr_t base, int offset, int value)
+{
+	writeb(value, PORT(base, offset));
+}
+
+void prom_putchar(char c)
+{
+	phys_addr_t uart_base =
+		(phys_addr_t) ioremap_nocache(LOONGSON_UART_BASE, 8);
+
+	while ((serial_in(uart_base, UART_LSR) & UART_LSR_THRE) == 0)
+		;
+
+	serial_out(uart_base, UART_TX, c);
+}