MIPS: Add initial support for the Atheros AR71XX/AR724X/AR931X SoCs

This patch adds initial support for various Atheros SoCs based on the
MIPS 24Kc core. The following models are supported at the moment:

  - AR7130
  - AR7141
  - AR7161
  - AR9130
  - AR9132
  - AR7240
  - AR7241
  - AR7242

The current patch contains minimal support only, but the resulting
kernel can boot into user-space with using of an initramfs image on
various boards which are using these SoCs. Support for more built-in
devices and individual boards will be implemented in further patches.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Imre Kaloz <kaloz@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: Luis R. Rodriguez <lrodriguez@atheros.com>
Cc: Cliff Holden <Cliff.Holden@Atheros.com>
Cc: Kathy Giori <Kathy.Giori@Atheros.com>
Patchwork: https://patchwork.linux-mips.org/patch/1947/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/arch/mips/ath79/early_printk.c b/arch/mips/ath79/early_printk.c
new file mode 100644
index 000000000000..7499b0e9df26
--- /dev/null
+++ b/arch/mips/ath79/early_printk.c
@@ -0,0 +1,36 @@
+/*
+ *  Atheros AR71XX/AR724X/AR913X SoC early printk support
+ *
+ *  Copyright (C) 2008-2010 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  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.
+ */
+
+#include <linux/io.h>
+#include <linux/serial_reg.h>
+#include <asm/addrspace.h>
+
+#include <asm/mach-ath79/ar71xx_regs.h>
+
+static inline void prom_wait_thre(void __iomem *base)
+{
+	u32 lsr;
+
+	do {
+		lsr = __raw_readl(base + UART_LSR * 4);
+		if (lsr & UART_LSR_THRE)
+			break;
+	} while (1);
+}
+
+void prom_putchar(unsigned char ch)
+{
+	void __iomem *base = (void __iomem *)(KSEG1ADDR(AR71XX_UART_BASE));
+
+	prom_wait_thre(base);
+	__raw_writel(ch, base + UART_TX * 4);
+	prom_wait_thre(base);
+}