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>
diff --git a/arch/mips/ath79/dev-common.c b/arch/mips/ath79/dev-common.c
new file mode 100644
index 0000000..3cfa100
--- /dev/null
+++ b/arch/mips/ath79/dev-common.c
@@ -0,0 +1,67 @@
+/*
+ *  Atheros AR71XX/AR724X/AR913X common devices
+ *
+ *  Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ *
+ *  Parts of this file are based on Atheros' 2.6.15 BSP
+ *
+ *  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/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/serial_8250.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+#include "common.h"
+#include "dev-common.h"
+
+static struct resource ath79_uart_resources[] = {
+	{
+		.start	= AR71XX_UART_BASE,
+		.end	= AR71XX_UART_BASE + AR71XX_UART_SIZE - 1,
+		.flags	= IORESOURCE_MEM,
+	},
+};
+
+#define AR71XX_UART_FLAGS (UPF_BOOT_AUTOCONF | UPF_SKIP_TEST | UPF_IOREMAP)
+static struct plat_serial8250_port ath79_uart_data[] = {
+	{
+		.mapbase	= AR71XX_UART_BASE,
+		.irq		= ATH79_MISC_IRQ_UART,
+		.flags		= AR71XX_UART_FLAGS,
+		.iotype		= UPIO_MEM32,
+		.regshift	= 2,
+	}, {
+		/* terminating entry */
+	}
+};
+
+static struct platform_device ath79_uart_device = {
+	.name		= "serial8250",
+	.id		= PLAT8250_DEV_PLATFORM,
+	.resource	= ath79_uart_resources,
+	.num_resources	= ARRAY_SIZE(ath79_uart_resources),
+	.dev = {
+		.platform_data	= ath79_uart_data
+	},
+};
+
+void __init ath79_register_uart(void)
+{
+	struct clk *clk;
+
+	clk = clk_get(NULL, "uart");
+	if (IS_ERR(clk))
+		panic("unable to get UART clock, err=%ld", PTR_ERR(clk));
+
+	ath79_uart_data[0].uartclk = clk_get_rate(clk);
+	platform_device_register(&ath79_uart_device);
+}