Add autotools configuration.

This patch adds a basic auto-tools configuration environment for the
bootwrapper consisting of the configure.ac file and the Makefile.am
file.

The configure.ac file includes several options and checks:
  - Ensure that an AArch64 compiler is used.
  - Add the mandatory --with-kernel-dir option that sets KERN_DIR.
  - Check that the correct base dtb file exists in KERN_DIR.
  - Add an option, --with-initrd, that allows a user to specify an
    initrd file to embed in the image.
  - Check for a working dtc and set DTC to the full-path to the
    executable.
  - Create the necessary symbolic links to the relevant kernel files.

The Makefile.am file includes several changes:

- Use a prebuilt dtb rather than a dts, which is decompiled to inject
  the chosen node.
- Use the configured compiler tool names.
- Use the configured SED program rather than assuming it is in PATH.

Signed-off-by: Matthew Leach <matthew.leach@arm.com>
[Mark: use dtb, add options, fix style issues, remove src/]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>

4 files changed, 112 insertions, 41 deletions

diff --git a/.gitignore b/.gitignore
index f63ca94..4dfd7fc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,19 @@
 *.dts
 *.dtsi
 *.o
-Image
+aclocal.m4
+autom4te.cache/
+config.guess
+config.log
+config.status
+config.sub
+configure
 dtc
+fdt.dtb
+Image
+install-sh
+Makefile
+Makefile.in
+missing
 model.lds
+patches/
diff --git a/Makefile b/Makefile.am
index b7fb61d..fd66c8c 100644
--- a/Makefile
+++ b/Makefile.am
@@ -1,5 +1,6 @@
 #
-# Makefile - build a kernel+filesystem image for stand-alone Linux booting
+# Makefile.am - build a kernel+filesystem image for stand-alone Linux
+# booting
 #
 # Copyright (C) 2012 ARM Limited. All rights reserved.
 #
@@ -15,76 +16,58 @@ GIC_CPU_BASE	:= 0x2c002000
 CNTFRQ		:= 0x01800000	# 24Mhz
 CPU_IDS		?= 0x0,0x1,0x2,0x3
 
-DEFINES		+= -DCNTFRQ=$(CNTFRQ)
+DEFINES		= -DCNTFRQ=$(CNTFRQ)
 DEFINES		+= -DCPU_IDS=$(CPU_IDS)
 DEFINES		+= -DGIC_CPU_BASE=$(GIC_CPU_BASE)
 DEFINES		+= -DGIC_DIST_BASE=$(GIC_DIST_BASE)
 DEFINES		+= -DSYSREGS_BASE=$(SYSREGS_BASE)
 DEFINES		+= -DUART_BASE=$(UART_BASE)
 
-#INITRD_FLAGS	:= -DUSE_INITRD
-CPPFLAGS	+= $(INITRD_FLAGS)
-
 BOOTLOADER	:= boot.S
 BOOTMETHOD	:= psci.o
 MBOX_OFFSET	:= 0xfff8
-KERNEL		:= Image
 KERNEL_OFFSET	:= 0x80000
 LD_SCRIPT	:= model.lds.S
 IMAGE		:= linux-system.axf
 
-FILESYSTEM	:= filesystem.cpio.gz
 FS_OFFSET	:= 0x10000000
 FILESYSTEM_START:= $(shell echo $$(($(PHYS_OFFSET) + $(FS_OFFSET))))
 FILESYSTEM_SIZE	:= $(shell stat -Lc %s $(FILESYSTEM) 2>/dev/null || echo 0)
 FILESYSTEM_END	:= $(shell echo $$(($(FILESYSTEM_START) + $(FILESYSTEM_SIZE))))
 
-FDT_SRC		:= rtsm_ve-aemv8a.dts
-FDT_INCL_REGEX	:= \(/include/[[:space:]]*"\)\([^"]\+\)\(".*\)
-FDT_DEPS	:= $(FDT_SRC) $(addprefix $(dir $(FDT_SRC)), $(shell sed -ne 'sq$(strip $(FDT_INCL_REGEX)q\2q p' < $(FDT_SRC))))
 FDT_OFFSET	:= 0x08000000
 
-BOOTARGS_COMMON	:= "console=ttyAMA0 earlyprintk=pl011,0x1c090000 $(BOOTARGS_EXTRA)"
-
-ifneq (,$(findstring USE_INITRD,$(CPPFLAGS)))
-BOOTARGS	:= "$(BOOTARGS_COMMON)"
+if INITRD
+INITRD_FLAGS	:= -DUSE_INITRD
 CHOSEN_NODE	:= chosen {						\
-			bootargs = \"$(BOOTARGS)\";			\
+			bootargs = \"$(CMDLINE)\";			\
 			linux,initrd-start = <$(FILESYSTEM_START)>;	\
 			linux,initrd-end = <$(FILESYSTEM_END)>;		\
 		   };
 else
-BOOTARGS	:= "root=/dev/nfs nfsroot=\<serverip\>:\<rootfs\>,tcp rw ip=dhcp $(BOOTARGS_COMMON)"
+INITRD_FLAGS	:=
 CHOSEN_NODE	:= chosen {						\
-			bootargs = \"$(BOOTARGS)\";			\
+			bootargs = \"$(CMDLINE)\";			\
 		   };
 endif
 
-CROSS_COMPILE	?= aarch64-none-linux-gnu-
-CC		:= $(CROSS_COMPILE)gcc
-LD		:= $(CROSS_COMPILE)ld
-DTC		:= $(if $(wildcard ./dtc), ./dtc, $(shell which dtc))
+CPPFLAGS	+= $(INITRD_FLAGS)
 
 all: $(IMAGE)
 
-clean:
-	rm -f $(IMAGE) boot.o cache.o gic.o mmu.o ns.o $(BOOTMETHOD) model.lds fdt.dtb
+CLEANFILES = $(IMAGE) boot.o cache.o gic.o mmu.o ns.o $(BOOTMETHOD) model.lds fdt.dtb
 
-$(IMAGE): boot.o cache.o gic.o mmu.o ns.o $(BOOTMETHOD) model.lds fdt.dtb $(KERNEL) $(FILESYSTEM)
+$(IMAGE): boot.o cache.o gic.o mmu.o ns.o $(BOOTMETHOD) model.lds fdt.dtb $(KERNEL_IMAGE) $(FILESYSTEM)
 	$(LD) -o $@ --script=model.lds
 
 %.o: %.S Makefile
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(DEFINES) -c -o $@ $<
 
 model.lds: $(LD_SCRIPT) Makefile
-	$(CC) $(CPPFLAGS) -DPHYS_OFFSET=$(PHYS_OFFSET) -DMBOX_OFFSET=$(MBOX_OFFSET) -DKERNEL_OFFSET=$(KERNEL_OFFSET) -DFDT_OFFSET=$(FDT_OFFSET) -DFS_OFFSET=$(FS_OFFSET) -DKERNEL=$(KERNEL) -DFILESYSTEM=$(FILESYSTEM) -DBOOTMETHOD=$(BOOTMETHOD) -E -P -C -o $@ $<
-
-ifeq ($(DTC),)
-	$(error No dtc found! You can git clone from git://git.jdl.com/software/dtc.git)
-endif
+	$(CPP) $(CPPFLAGS) -ansi -DPHYS_OFFSET=$(PHYS_OFFSET) -DMBOX_OFFSET=$(MBOX_OFFSET) -DKERNEL_OFFSET=$(KERNEL_OFFSET) -DFDT_OFFSET=$(FDT_OFFSET) -DFS_OFFSET=$(FS_OFFSET) -DKERNEL=$(KERNEL_IMAGE) -DFILESYSTEM=$(FILESYSTEM) -DBOOTMETHOD=$(BOOTMETHOD) -P -C -o $@ $<
 
-fdt.dtb: $(FDT_DEPS) Makefile
-	( echo "/include/ \"$(FDT_SRC)\"" ; echo "/ { $(CHOSEN_NODE) };" ) | $(DTC) -O dtb -o $@ -
+fdt.dtb: $(KERNEL_DTB) Makefile
+	( $(DTC) -O dts -I dtb $(KERNEL_DTB) ; echo "/ { $(CHOSEN_NODE) };" ) | $(DTC) -O dtb -o $@ -
 
 # The filesystem archive might not exist if INITRD is not being used
 .PHONY: all clean $(FILESYSTEM)
diff --git a/README b/README
index 0c211b1..7013e25 100644
--- a/README
+++ b/README
@@ -1,14 +1,14 @@
 Linux boot wrapper with FDT support
 ===================================
 
-The following files need to be linked into the boot wrapper directory:
+To get started:
 
-dtc			 - point to <linux-build-dir>/scripts/dtc/dtc
-rtsm_ve-aemv8a.dts       - point to <linux-src-dir>/arch/arm64/boot/dts/rtsm_ve-aemv8a.dts
-rtsm_ve-motherboard.dtsi - point to <linux-src-dir>/arch/arm64/boot/dts/rtsm_ve-motherboard.dtsi
-skeleton.dtsi		 - point to <linux-src-dir>/arch/arm64/boot/dts/skeleton.dtsi
+$ autoreconf -i
+$ ./configure --host=<toolchain-triplet> --with-kernel-dir=<kernel-dir> <other-options>
+$ make
 
-Alternatively, you may specify the paths for dtc and the main dts file
-on the make command-line. For example:
-
-make DTC=<path-to-dtc> FDT_SRC=<linux-src-dir>/arch/arm64/boot/dts/vexpress-v2p-aarch64.dtsi
+Where:
+ - <toolchain-triplet>: this is something like aarch64-linux-gnu
+ - <kernel-dir>: the directory containing a pre-built aarch64 kernel
+   and its sources.
+ - <other-options>: see ./configure -h for a list of other options.
diff --git a/configure.ac b/configure.ac
new file mode 100644
index 0000000..fdb5e17
--- /dev/null
+++ b/configure.ac
@@ -0,0 +1,75 @@
+# configure.ac - autoconf script for the AArch64 bootwrapper
+#
+# Copyright (c) 2014 ARM Limited. All rights reserved.
+#
+# Use of this source code is governed by a BSD-style license that can
+# be found in the LICENSE.txt file.
+
+AC_INIT([aarch64-boot-wrapper], [v0.1])
+
+# Ensure that we're using an AArch64 compiler
+AC_CANONICAL_SYSTEM
+
+if test "x$host_cpu" != "xaarch64"; then
+	AC_MSG_ERROR([The boot-wrapper can only be used with an AArch64 compiler.])
+fi
+
+AM_INIT_AUTOMAKE([foreign])
+
+# Allow a user to pass --with-kernel-dir
+AC_ARG_WITH([kernel-dir],
+	AS_HELP_STRING([--with-kernel-dir], [specify the root Linux kernel build directory (required)]),
+	AC_SUBST([KERN_DIR], [$withval]),
+	AC_MSG_ERROR([No kernel directory specified. Use --with-kernel-dir]))
+KERN_IMAGE=/arch/arm64/boot/Image
+KERN_DTB=/arch/arm64/boot/dts/rtsm_ve-aemv8a.dtb
+
+# Ensure that the user has provided us with a sane kernel dir.
+m4_define([CHECKFILES], [KERN_DIR,
+	KERN_DIR$KERN_DTB,
+	KERN_DIR$KERN_IMAGE])
+
+m4_foreach([checkfile], [CHECKFILES],
+	[AC_CHECK_FILE([$checkfile], [], AC_MSG_ERROR([No such file or directory: $checkfile]))])
+
+AC_SUBST([KERNEL_IMAGE], [$KERN_DIR$KERN_IMAGE])
+AC_SUBST([KERNEL_DTB], [$KERN_DIR$KERN_DTB])
+
+# Allow a user to pass --with-initrd
+AC_ARG_WITH([initrd],
+	AS_HELP_STRING([--with-initrd], [embed an initrd in the kernel image]),
+	USE_INITRD=$withval)
+AC_SUBST([FILESYSTEM], [$USE_INITRD])
+AM_CONDITIONAL([INITRD], [test "x$USE_INITRD" != "x"])
+
+C_CMDLINE="console=ttyAMA0 earlyprintk=pl011,0x1c090000"
+AC_ARG_WITH([cmdline],
+	AS_HELP_STRING([--with-cmdline], [set a command line for the kernel]),
+	[C_CMDLINE=$withval])
+AC_SUBST([CMDLINE], [$C_CMDLINE])
+
+# Ensure that we have all the needed programs
+AC_PROG_CC
+AC_PROG_CPP
+AM_PROG_AS
+AC_PROG_SED
+AC_PROG_LN_S
+AC_PATH_PROG([DTC], dtc, error)
+if test "x$DTC" = "xerror"; then
+	AC_MSG_ERROR([cannot find the device tree compiler (dtc)])
+fi
+AC_CHECK_TOOL(LD, ld)
+
+AC_CONFIG_FILES([Makefile])
+
+AC_OUTPUT
+
+# Print the final config to the user.
+echo ""
+echo "  Boot wrapper configuration"
+echo "  =========================="
+echo ""
+echo "  Linux kernel build dir:            ${KERN_DIR}"
+echo "  Linux kernel command line:         ${CMDLINE}"
+echo "  Embedded initrd:                   ${FILESYSTEM:-NONE}"
+echo ""