ARC: Build system: Makefiles, Kconfig, Linker script

Arnd in his review pointed out that arch Kconfig organisation has several
deficiencies:

* Build time entries for things which can be runtime extracted from DT
  (e.g. SDRAM size, core clk frequency..)
* Not multi-platform-image-build friendly (choice .. endchoice constructs)
* cpu variants support (750/770) is exclusive.

The first 2 have been fixed in subsequent patches.
Due to the nature of the 750 and 770, it is not possible to build for
both together, w/o special runtime glue code which would hurt
performance.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 115 insertions, 0 deletions

diff --git a/arch/arc/Makefile b/arch/arc/Makefile
new file mode 100644
index 00000000000..4d52a3bb68a
--- /dev/null
+++ b/arch/arc/Makefile
@@ -0,0 +1,115 @@
+#
+# Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+#
+# 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.
+#
+
+UTS_MACHINE := arc
+
+KBUILD_DEFCONFIG := fpga_defconfig
+
+# For ARC FPGA Platforms
+platform-$(CONFIG_ARC_PLAT_FPGA_LEGACY)	:= arcfpga
+#New platform adds here
+
+PLATFORM := $(platform-y)
+export PLATFORM
+
+cflags-y	+= -Iarch/arc/plat-$(PLATFORM)/include
+cflags-y	+= -mA7 -fno-common -pipe -fno-builtin -D__linux__
+
+atleast_gcc44 :=  $(call cc-ifversion, -gt, 0402, y)
+cflags-$(atleast_gcc44)			+= -fsection-anchors
+
+cflags-$(CONFIG_ARC_HAS_LLSC)		+= -mlock
+cflags-$(CONFIG_ARC_HAS_SWAPE)		+= -mswape
+cflags-$(CONFIG_ARC_HAS_RTSC)		+= -mrtsc
+cflags-$(CONFIG_ARC_DW2_UNWIND)		+= -fasynchronous-unwind-tables
+
+ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
+# Generic build system uses -O2, we want -O3
+cflags-y  += -O3
+endif
+
+# small data is default for elf32 tool-chain. If not usable, disable it
+# This also allows repurposing GP as scratch reg to gcc reg allocator
+disable_small_data := y
+cflags-$(disable_small_data)		+= -mno-sdata -fcall-used-gp
+
+cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= -mbig-endian
+ldflags-$(CONFIG_CPU_BIG_ENDIAN)	+= -EB
+
+# STAR 9000518362:
+# arc-linux-uclibc-ld (buildroot) or arceb-elf32-ld (EZChip) don't accept
+# --build-id w/o "-marclinux".
+# Default arc-elf32-ld is OK
+ldflags-y				+= -marclinux
+
+ARC_LIBGCC				:= -mA7
+cflags-$(CONFIG_ARC_HAS_HW_MPY)		+= -multcost=16
+
+ifndef CONFIG_ARC_HAS_HW_MPY
+	cflags-y	+= -mno-mpy
+
+# newlib for ARC700 assumes MPY to be always present, which is generally true
+# However, if someone really doesn't want MPY, we need to use the 600 ver
+# which coupled with -mno-mpy will use mpy emulation
+# With gcc 4.4.7, -mno-mpy is enough to make any other related adjustments,
+# e.g. increased cost of MPY. With gcc 4.2.1 this had to be explicitly hinted
+
+	ARC_LIBGCC		:= -marc600
+	ifneq ($(atleast_gcc44),y)
+		cflags-y	+= -multcost=30
+	endif
+endif
+
+LIBGCC	:= $(shell $(CC) $(ARC_LIBGCC) $(cflags-y) --print-libgcc-file-name)
+
+# Modules with short calls might break for calls into builtin-kernel
+KBUILD_CFLAGS_MODULE	+= -mlong-calls
+
+# Finally dump eveything into kernel build system
+KBUILD_CFLAGS	+= $(cflags-y)
+KBUILD_AFLAGS	+= $(KBUILD_CFLAGS)
+LDFLAGS		+= $(ldflags-y)
+
+# Needed for Linker script preprocessing
+KBUILD_CPPFLAGS	+= -Iarch/arc/plat-$(PLATFORM)/include
+
+head-y		:= arch/arc/kernel/head.o
+
+# See arch/arc/Kbuild for content of core part of the kernel
+core-y		+= arch/arc/
+
+# w/o this ifneq, make ARCH=arc clean was crapping out
+ifneq ($(platform-y),)
+core-y		+= arch/arc/plat-$(PLATFORM)/
+endif
+
+libs-y		+= arch/arc/lib/ $(LIBGCC)
+
+#default target for make without any arguements.
+KBUILD_IMAGE := bootpImage
+
+all:	$(KBUILD_IMAGE)
+boot	:= arch/arc/boot
+
+bootpImage: vmlinux
+
+uImage: vmlinux
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+
+archclean:
+	$(Q)$(MAKE) $(clean)=$(boot)
+
+# Hacks to enable final link due to absence of link-time branch relexation
+# and gcc choosing optimal(shorter) branches at -O3
+#
+# vineetg Feb 2010: -mlong-calls switched off for overall kernel build
+# However lib/decompress_inflate.o (.init.text) calls
+# zlib_inflate_workspacesize (.text) causing relocation errors.
+# Thus forcing all exten calls in this file to be long calls
+export CFLAGS_decompress_inflate.o = -mmedium-calls
+export CFLAGS_initramfs.o = -mmedium-calls