system-arm: Rework boot loader makefile to be more generic

add all, clean and install rules
use variables for CROSS_COMPILE, CC, LD, DESTDIR
use generic rules to produce objects and link

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
[ciro.santilli@arm.com: Also add BUILDDIR and to allow fully
 out-of-tree builds.]
Signed-off-by: Ciro Santilli <ciro.santilli@arm.com>
Change-Id: Id84bc6a8e5dde409b6fb968925ca268376730196
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22823
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/system/arm/aarch64_bootloader/makefile b/system/arm/aarch64_bootloader/makefile
index 9ffff76..079e9b5 100644
--- a/system/arm/aarch64_bootloader/makefile
+++ b/system/arm/aarch64_bootloader/makefile
@@ -1,7 +1,67 @@
-build:
-	aarch64-linux-gnu-gcc -c  -DPHYS_OFFSET=0x80000000 -DCNTFRQ=0x01800000 -DUART_BASE=0x1c090000 -DSYSREGS_BASE=0x1c010000 -DGIC_DIST_BASE=0x2c001000 -DGIC_CPU_BASE=0x2c002000 -Dkernel=0x80080000 -Dmbox=0x8000fff8 -Ddtb=0x80000100 -o boot_emm.o -march=armv8-a boot.S
-	aarch64-linux-gnu-ld -o boot_emm.arm64 -N -Ttext 0x00000010 boot_emm.o -non_shared -static
-	rm boot_emm.o
-	aarch64-linux-gnu-gcc -c  -DGICV3 -DPHYS_OFFSET=0x80000000 -DCNTFRQ=0x01800000 -DUART_BASE=0x1c090000 -DSYSREGS_BASE=0x1c010000 -DGIC_DIST_BASE=0x2c000000 -DGIC_REDIST_BASE=0x2c010000 -Dkernel=0x80080000 -Dmbox=0x8000fff8 -Ddtb=0x80000100 -o boot_emm_v2.o -march=armv8-a boot.S
-	aarch64-linux-gnu-ld -o boot_emm_v2.arm64 -N -Ttext 0x00000010 boot_emm_v2.o -non_shared -static
-	rm boot_emm_v2.o
+# Copyright (c) 2019 ARM Limited
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met: redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer;
+# redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution;
+# neither the name of the copyright holders nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+CROSS_COMPILE = aarch64-linux-gnu-
+CC = $(CROSS_COMPILE)gcc
+LD = $(CROSS_COMPILE)ld
+
+BUILDDIR = .
+DESTDIR = $(error Please set DESTDIR to wanted installation directory)
+
+CFLAGS = -march=armv8-a
+CPPFLAGS = -DPHYS_OFFSET=0x80000000 -DCNTFRQ=0x01800000 \
+		   -DUART_BASE=0x1c090000 -DSYSREGS_BASE=0x1c010000 \
+		   -DGIC_DIST_BASE=0x2c001000 -Dkernel=0x80080000 \
+		   -Dmbox=0x8000fff8 -Ddtb=0x80000100
+
+LDFLAGS = -N -Ttext 0x00000010 -non_shared -static
+
+.PHONY: all clean install mkdir
+
+all: mkdir $(BUILDDIR)/boot_emm.arm64 $(BUILDDIR)/boot_emm_v2.arm64
+
+#v1 has a GIC V2
+$(BUILDDIR)/boot_emm.o: CPPFLAGS += -UGICV3 -DGIC_CPU_BASE=0x2c002000
+
+#V2 has a GIC V3
+$(BUILDDIR)/boot_emm_v2.o: CPPFLAGS += -DGICV3 -DGIC_REDIST_BASE=0x2c010000
+
+$(BUILDDIR)/%.arm64: $(BUILDDIR)/%.o
+	$(LD) -o $@ $< $(LDFLAGS)
+
+$(BUILDDIR)/%.o: boot.S
+	$(CC) $(CPPFLAGS) -c $< -o $@ $(CFLAGS)
+
+install:
+	mkdir -p $(DESTDIR)
+	install -m 644 $(BUILDDIR)/boot_emm.arm64 $(BUILDDIR)/boot_emm_v2.arm64 $(DESTDIR)/.
+
+mkdir:
+	mkdir -p $(BUILDDIR)
+
+clean:
+	rm -f $(BUILDDIR)/*.o
+	rm -f $(BUILDDIR)/boot_emm.arm64 $(BUILDDIR)/boot_emm_v2.arm64