From 0c024b14e881cb4739f80017ac4c100941eb6faa Mon Sep 17 00:00:00 2001
From: Jonathon Hall <jonathon.hall@puri.sm>
Date: Thu, 10 Aug 2023 16:49:58 -0400
Subject: [PATCH] modules/coreboot: Reuse release toolchain for fork builds

Reuse the toolchain from a coreboot release for fork builds.  Either
the fork or the release can be built first, in either case the
release's toolchain is built at the default location and reused for
later builds.

Signed-off-by: Jonathon Hall <jonathon.hall@puri.sm>
---
 modules/coreboot | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

diff --git a/modules/coreboot b/modules/coreboot
index fa43e9fd..77ed7796 100644
--- a/modules/coreboot
+++ b/modules/coreboot
@@ -105,6 +105,21 @@ $(build)/$(coreboot_dir)/.configured: $(CONFIG_COREBOOT_CONFIG)
 
 EXTRA_FLAGS ?= -fdebug-prefix-map=$(pwd)=heads -gno-record-gcc-switches -Wno-error=packed-not-aligned -Wno-address-of-packed-member
 
+# Select the coreboot version to use for the toolchain
+ifeq "$($(coreboot_module)_toolchain)" ""
+	# Use the same module
+	coreboot_toolchain_module := $(coreboot_module)
+else
+	# Use a different module
+	coreboot_toolchain_module := coreboot-$($(coreboot_module)_toolchain)
+	modules-y += $(coreboot_toolchain_module)
+	# The toolchain module won't build anything for this board, we just need
+	# the module prepped so we can hook up the toolchain target
+	$(coreboot_toolchain_module)_output := .nobuild
+	$(coreboot-toolchain_module)_configure := echo -e 'all:\n\ttouch .nobuild' > Makefile.nobuild
+	$(coreboot-toolchain_module)_target := -f Makefile.nobuild
+endif
+
 $(coreboot_module)_configure := \
 	mkdir -p "$(build)/$(coreboot_dir)" \
 	&& $(call install_config,$(pwd)/$(CONFIG_COREBOOT_CONFIG),$(build)/$(coreboot_dir)/.config) \
@@ -118,10 +133,24 @@ $(coreboot_module)_configure := \
 		CFLAGS_x86_32="$(EXTRA_FLAGS)" \
 		CFLAGS_x86_64="$(EXTRA_FLAGS)" \
 
+# Cache the cross compilation config with this toolchain.  The first build
+# generates this, then it's reused later.
+COREBOOT_TOOLCHAIN=$(build)/$(coreboot_base_dir)/.xcompile
+# Build the toolchain if the .xcompile cache doesn't exist yet.  This doesn't
+# actually generate .xcompile, but it at least orders the toolchain build
+# correctly.
+$(COREBOOT_TOOLCHAIN): $(build)/$($(coreboot_toolchain_module)_base_dir)/.canary
+	$(MAKE) -C "$(build)/$($(coreboot_toolchain_module)_base_dir)" CPUS=$(CPUS) "crossgcc-$(COREBOOT_TARGET)"
+
+$(build)/$(coreboot_dir)/.configured: $(COREBOOT_TOOLCHAIN)
+
+# Build with the cross toolchain from the toolchain module (which might be the
+# same coreboot module or a different one).
 $(coreboot_module)_target := \
 	-C "$(build)/$(coreboot_base_dir)" \
 	obj="$(build)/$(coreboot_dir)" \
 	DOTCONFIG="$(build)/$(coreboot_dir)/.config" \
+	XGCCPATH="$(build)/$($(coreboot_toolchain_module)_base_dir)/util/crossgcc/xgcc/bin/" \
 	xcompile="$(build)/$(coreboot_base_dir)/.xcompile" \
 	$(COREBOOT_TARGET_CROSS) \
 	BUILD_TIMELESS=1 \
@@ -133,12 +162,6 @@ $(coreboot_module)_output := $(CONFIG_COREBOOT_ROM)
 $(coreboot_module)_output += $(CONFIG_COREBOOT_BOOTBLOCK)
 $(coreboot_module)_depend += linux initrd $(musl_dep)
 
-COREBOOT_TOOLCHAIN=$(build)/$(coreboot_base_dir)/.xcompile
-$(COREBOOT_TOOLCHAIN): $(build)/$(coreboot_base_dir)/.canary
-	$(MAKE) -C "$(build)/$(coreboot_base_dir)" CPUS=$(CPUS) "crossgcc-$(COREBOOT_TARGET)"
-
-$(build)/$(coreboot_dir)/.configured: $(COREBOOT_TOOLCHAIN)
-
 # Force a rebuild if the inputs have changed
 $(build)/$(coreboot_dir)/.build: \
 	$(build)/$(BOARD)/$(LINUX_IMAGE_FILE) \