arm: Add Aspeed machine

Aspeed devices are a common Baseboard Management Controller (BMC)
system on chip containing an ARM9 or ARM11 core, off-chip DDR RAM and
support for a large number of peripherals.

This patch adds basic support for the ast2400 and ast2500 machines,
capable of booting to a prompt in QEMU (-M palmetto-bmc), on an
Palmetto OpenPower development machine, and on the ast2500 EVB.

Signed-off-by: Joel Stanley <[e-mail]>

MAINTAINERS

···
 F:	arch/arm/boot/dts/artpec6*
 F:	drivers/clk/clk-artpec6.c
 
+ARM/ASPEED MACHINE SUPPORT
+M:	Joel Stanley <[e-mail]>
+S:	Maintained
+F:	arch/arm/mach-aspeed/
+F:	arch/arm/boot/dts/aspeed-*
+F:	drivers/*/*aspeed*
+
 ARM/ATMEL AT91RM9200, AT91SAM9 AND SAMA5 SOC SUPPORT
 M:	Nicolas Ferre <[e-mail]>
 M:	Alexandre Belloni <[e-mail]>

arch/arm/Kconfig

···
 
 source "arch/arm/mach-moxart/Kconfig"
 
+source "arch/arm/mach-aspeed/Kconfig"
+
 source "arch/arm/mach-mv78xx0/Kconfig"
 
 source "arch/arm/mach-imx/Kconfig"

arch/arm/mach-aspeed/Kconfig

···
+menuconfig ARCH_ASPEED
+	bool "Aspeed BMC architectures"
+	depends on ARCH_MULTI_V5 || ARCH_MULTI_V6
+	select SRAM
+	select WATCHDOG
+	select ASPEED_WATCHDOG
+	select MOXART_TIMER
+	help
+	  Say Y here if you want to run your kernel on an ASpeed BMC SoC.
+
+if ARCH_ASPEED
+
+config MACH_ASPEED_G4
+	bool "Aspeed SoC 4th Generation"
+	depends on ARCH_MULTI_V5
+	select CPU_ARM926T
+	help
+	 Say yes if you intend to run on an Aspeed ast2400 or similar
+	 fourth generation BMCs, such as those used by OpenPower Power8
+	 systems.
+
+config MACH_ASPEED_G5
+	bool "Aspeed SoC 5th Generation"
+	depends on ARCH_MULTI_V6
+	select CPU_V6
+	help
+	 Say yes if you intend to run on an Aspeed ast2500 or similar
+	 fifth generation Aspeed BMCs.
+
+endif