nios2: Build infrastructure

This patch adds Makefile and Kconfig files required for building a
nios2 kernel.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
diff --git a/arch/nios2/Makefile b/arch/nios2/Makefile
new file mode 100644
index 0000000..e142c9ee
--- /dev/null
+++ b/arch/nios2/Makefile
@@ -0,0 +1,73 @@
+#
+# This file is subject to the terms and conditions of the GNU General Public
+# License.  See the file "COPYING" in the main directory of this archive
+# for more details.
+#
+# Copyright (C) 2013 Altera Corporation
+# Copyright (C) 1994, 95, 96, 2003 by Wind River Systems
+# Written by Fredrik Markstrom
+#
+# This file is included by the global makefile so that you can add your own
+# architecture-specific flags and dependencies. Remember to do have actions
+# for "archclean" cleaning up for this architecture.
+#
+# Nios2 port by Wind River Systems Inc trough:
+#   fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+
+UTS_SYSNAME = Linux
+
+export MMU
+
+LIBGCC		:= $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name)
+
+KBUILD_CFLAGS += -pipe -D__linux__ -D__ELF__
+KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_HW_MUL_SUPPORT),-mhw-mul,-mno-hw-mul)
+KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_HW_MULX_SUPPORT),-mhw-mulx,-mno-hw-mulx)
+KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_HW_DIV_SUPPORT),-mhw-div,-mno-hw-div)
+KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_FPU_SUPPORT),-mcustom-fpu-cfg=60-1,)
+
+KBUILD_CFLAGS += -fno-optimize-sibling-calls
+KBUILD_CFLAGS += -DUTS_SYSNAME=\"$(UTS_SYSNAME)\"
+KBUILD_CFLAGS += -fno-builtin
+KBUILD_CFLAGS += -G 0
+
+head-y		:= arch/nios2/kernel/head.o
+libs-y		+= arch/nios2/lib/ $(LIBGCC)
+core-y		+= arch/nios2/kernel/ arch/nios2/mm/
+core-y		+= arch/nios2/platform/
+
+INSTALL_PATH ?= /tftpboot
+nios2-boot := arch/$(ARCH)/boot
+BOOT_TARGETS = vmImage zImage
+PHONY += $(BOOT_TARGETS) install
+KBUILD_IMAGE := $(nios2-boot)/vmImage
+
+ifneq ($(CONFIG_NIOS2_DTB_SOURCE),"")
+	core-y	+= $(nios2-boot)/
+endif
+
+all: vmImage
+
+archclean:
+	$(Q)$(MAKE) $(clean)=$(nios2-boot)
+
+%.dtb:
+	$(Q)$(MAKE) $(build)=$(nios2-boot) $(nios2-boot)/$@
+
+dtbs:
+	$(Q)$(MAKE) $(build)=$(nios2-boot) $(nios2-boot)/$@
+
+$(BOOT_TARGETS): vmlinux
+	$(Q)$(MAKE) $(build)=$(nios2-boot) $(nios2-boot)/$@
+
+install:
+	$(Q)$(MAKE) $(build)=$(nios2-boot) BOOTIMAGE=$(KBUILD_IMAGE) install
+
+define archhelp
+  echo  '* vmImage         - Kernel-only image for U-Boot ($(KBUILD_IMAGE))'
+  echo  '  install         - Install kernel using'
+  echo  '                     (your) ~/bin/$(INSTALLKERNEL) or'
+  echo  '                     (distribution) /sbin/$(INSTALLKERNEL) or'
+  echo  '                     install to $$(INSTALL_PATH)'
+  echo  '  dtbs            - Build device tree blobs for enabled boards'
+endef