Hey John,
Le 23/01/2013 13:05, John Crispin a écrit :
Add the code needed to make early printk work.
Signed-off-by: John Crispin <blogic@xxxxxxxxxxx>
---
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@xxxxxxxxxxx>
+ */
+
+#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
Is that really required considering that you already include
serial_reg.h and could use defines from there?
At some point I think that we might be able to come up with a some kind
of generic 8250 earlyprintk code where people just tell what's the base
address of their UART. Something like:
#define UART_BASE KSEG1ADDR(MY_UART_BASE)
#include <asm/8250-earlyprintk.h>
+
+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);
+}
