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/Kconfig b/arch/mips/Kconfig
index 9543040..e0215d9 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -66,6 +66,20 @@
 	  Support for the Texas Instruments AR7 System-on-a-Chip
 	  family: TNETD7100, 7200 and 7300.
 
+config ATH79
+	bool "Atheros AR71XX/AR724X/AR913X based boards"
+	select BOOT_RAW
+	select CEVT_R4K
+	select CSRC_R4K
+	select DMA_NONCOHERENT
+	select IRQ_CPU
+	select SYS_HAS_CPU_MIPS32_R2
+	select SYS_HAS_EARLY_PRINTK
+	select SYS_SUPPORTS_32BIT_KERNEL
+	select SYS_SUPPORTS_BIG_ENDIAN
+	help
+	  Support for the Atheros AR71XX/AR724X/AR913X SoCs.
+
 config BCM47XX
 	bool "Broadcom BCM47XX based boards"
 	select CEVT_R4K
@@ -718,6 +732,7 @@
 endchoice
 
 source "arch/mips/alchemy/Kconfig"
+source "arch/mips/ath79/Kconfig"
 source "arch/mips/bcm63xx/Kconfig"
 source "arch/mips/jazz/Kconfig"
 source "arch/mips/jz4740/Kconfig"