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Diffstat (limited to 'arch/mips/loongson/common/early_printk.c')
-rw-r--r--arch/mips/loongson/common/early_printk.c38
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);
+}
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