payloads/external/LinuxBoot: Clean up

There were some issues with the current Linuxboot Makefiles.
- multithreaded compilation didn't work, because some prerequisites
  were missing
- initramfs wasn't added for x86 qemu boot.
- riscv support was incomplete

It began with separate patches, but resulted in a clean up patch, that
is hard to separate. The most important changes are the following:
- Instead of phony targets, actual files are now used as prerequisites
- riscv can now be used as target
- initramfs works now also for x86
- instead of querying the most recent version from the internet, I set a
  known working version (because I tested it) that can be customized
  and/or upgraded in the future. The reasons:
      - querying the version from the internet requires a constant
        connection to the internet even after linux kernel is already
        build (aka subsequent builds).
      - one usually wants to use a known working version, but optionally
        still have the posibillity to choose a custom one. This patch
        introduces this possibility in its most simple form.
- I removed as much ifeq statements as possible and moved that
  responsibility to Kconfig, because they tend to make the
  Makefile less readable.

Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Change-Id: I25e757108e0dd473969fe5a192ad0733f1fe6286
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76150
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 35 insertions, 46 deletions

diff --git a/payloads/external/LinuxBoot/Makefile b/payloads/external/LinuxBoot/Makefile
index cd9f7eaa0e..d12d323f5e 100644
--- a/payloads/external/LinuxBoot/Makefile
+++ b/payloads/external/LinuxBoot/Makefile
@@ -1,62 +1,51 @@
 ## SPDX-License-Identifier: GPL-2.0-only
 
-project_dir=linuxboot
-
 unexport $(COREBOOT_EXPORTS)
 
-all: linuxboot
+DTC ?= dtc
 
-u-root:
-	$(MAKE) -f targets/u-root.mk
+LINUX_ARCH-$(CONFIG_LINUXBOOT_X86_64)     = x86_64
+LINUX_ARCH-$(CONFIG_LINUXBOOT_X86)        = i386
+LINUX_ARCH-$(CONFIG_LINUXBOOT_ARM64)      = arm64
+LINUX_ARCH-$(CONFIG_LINUXBOOT_RISCV_RV32) = riscv
+LINUX_ARCH-$(CONFIG_LINUXBOOT_RISCV_RV64) = riscv
 
-ifeq ($(CONFIG_LINUXBOOT_BUILD_INITRAMFS),y)
-ifeq ($(CONFIG_LINUXBOOT_UROOT),y)
-initramfs: u-root
-endif
-else
-ifneq ($(CONFIG_LINUXBOOT_INITRAMFS),)
-initramfs:
-	if [[ ! -f "$(top)/$(CONFIG_LINUXBOOT_INITRAMFS)" ]]; then \
-	echo "<< Linux initramfs '$(CONFIG_LINUXBOOT_INITRAMFS)' is missing. >>"; \
-	exit 1; \
-	fi
-endif
-endif
+build/Image: $(CONFIG_LINUXBOOT_KERNEL_PATH)
+	ln -s -r $< $@
+
+include targets/linux.mk targets/u-root.mk
 
-initramfs_compressed: initramfs
+build/initramfs: $(CONFIG_LINUXBOOT_INITRAMFS_PATH)
 ifeq ($(CONFIG_LINUXBOOT_INITRAMFS_COMPRESSION_XZ),y)
-	xz --keep --force --check=crc32 --lzma2=dict=1MiB $(top)/$(CONFIG_LINUXBOOT_INITRAMFS)
+	xz --keep --force --check=crc32 --lzma2=dict=1MiB $(CONFIG_LINUXBOOT_INITRAMFS_PATH)
 endif
+	cp $(CONFIG_LINUXBOOT_INITRAMFS_PATH)$(CONFIG_LINUXBOOT_INITRAMFS_SUFFIX) $@
 
-ifeq ($(CONFIG_LINUXBOOT_COMPILE_KERNEL),y)
-ifeq ($(CONFIG_LINUXBOOT_ARCH),arm64)
-kernel: initramfs
-	if [[ ! -f "$(top)/$(CONFIG_LINUXBOOT_DTB_FILE)" ]]; then \
-	echo "<< Linux kernel devicetree is missing. >>"; \
-	exit 1; \
-	fi
-	$(MAKE) -f targets/linux.mk
-else
-kernel:
-	$(MAKE) -f targets/linux.mk
-endif
-else
-kernel:
-	if [[ ! -f "$(top)/$(CONFIG_LINUXBOOT_KERNEL)" ]]; then \
-	echo "<< Linux kernel '$(CONFIG_LINUXBOOT_KERNEL)' is missing. >>"; \
-	exit 1; \
-	fi
-endif
+ifeq ($(CONFIG_LINUXBOOT_KERNEL_BZIMAGE),y)
+
+build/bzImage: $(kernel_dir)/arch/x86/boot/bzImage | build
+	cp $< $@
+
+else ifeq ($(CONFIG_LINUXBOOT_KERNEL_UIMAGE),y)
+
+build/target.dtb: $(CONFIG_LINUXBOOT_DTS_FILE)
+	$(DTC) -o $@ $<
+
+build/uImage: build/vmlinux.bin.lzma build/initramfs build/target.dtb $(LINUX_ARCH-y)/kernel_fdt_lzma.its | build
+	mkimage -f $(LINUX_ARCH-y)/kernel_fdt_lzma.its $@
+
+endif # CONFIG_LINUXBOOT_KERNEL_BZIMAGE
 
-linuxboot: kernel initramfs_compressed
+build:
+	mkdir build
 
 clean:
-	rm -rf $(project_dir)/kernel*
-	rm -f $(project_dir)/u-root
-	rm -f $(project_dir)/initramfs*
-	rm -f $(project_dir)/bzImage
+	rm -rf build/kernel*
+	rm -f  build/u-root
+	rm -f  build/initramfs*
+	rm -f  build/bzImage
 
 distclean:
-	rm -rf $(project_dir)
+	rm -rf build
 
-.PHONY: linuxboot kernel initramfs_compressed initramfs u-root clean distclean
+.PHONY: linuxboot clean distclean