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[RFC 08/11] MIPS: ralink: adds early_printk support

To: Ralf Baechle <ralf@linux-mips.org>
Subject: [RFC 08/11] MIPS: ralink: adds early_printk support
From: John Crispin <blogic@openwrt.org>
Date: Wed, 23 Jan 2013 13:05:52 +0100
Cc: linux-mips@linux-mips.org, John Crispin <blogic@openwrt.org>
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Add the code needed to make early printk work.

Signed-off-by: John Crispin <blogic@openwrt.org>
---
 arch/mips/ralink/early_printk.c |   43 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 arch/mips/ralink/early_printk.c

diff --git a/arch/mips/ralink/early_printk.c b/arch/mips/ralink/early_printk.c
new file mode 100644
index 0000000..c610084
--- /dev/null
+++ b/arch/mips/ralink/early_printk.c
@@ -0,0 +1,43 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  Copyright (C) 2011-2012 Gabor Juhos <juhosg@openwrt.org>
+ */
+
+#include <linux/io.h>
+#include <linux/serial_reg.h>
+
+#include <asm/addrspace.h>
+
+/* UART registers */
+#define EARLY_UART_BASE         0x10000c00
+
+#define UART_REG_RX             0
+#define UART_REG_TX             1
+#define UART_REG_IER            2
+#define UART_REG_IIR            3
+#define UART_REG_FCR            4
+#define UART_REG_LCR            5
+#define UART_REG_MCR            6
+#define UART_REG_LSR            7
+
+static inline void uart_w32(u32 val, unsigned reg)
+{
+       __raw_writel((val),
+               (void __iomem *)(KSEG1ADDR(EARLY_UART_BASE) + 4 * (reg)));
+}
+
+static inline u32 uart_r32(unsigned reg)
+{
+       return __raw_readl(
+               (void __iomem *)(KSEG1ADDR(EARLY_UART_BASE) + 4 * (reg)));
+}
+
+void prom_putchar(unsigned char ch)
+{
+       while (((uart_r32(UART_REG_LSR)) & UART_LSR_THRE) == 0);
+       uart_w32(UART_REG_TX, ch);
+       while (((uart_r32(UART_REG_LSR)) & UART_LSR_THRE) == 0);
+}
-- 
1.7.10.4


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