From 228b68ce5b7405b3bda609645a90da309e465798 Mon Sep 17 00:00:00 2001
From: Gulshan Singh <gsingh2011@gmail.com>
Date: Sun, 25 Feb 2024 19:52:13 -0800
Subject: [PATCH 1/4] Added u-boot submodule

---
 .gitmodules | 3 +++
 u-boot      | 1 +
 2 files changed, 4 insertions(+)
 create mode 160000 u-boot

diff --git a/.gitmodules b/.gitmodules
index 7eab220..7159958 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -10,3 +10,6 @@
 	path = linux
 	url = https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/
 	branch = master
+[submodule "u-boot"]
+	path = u-boot
+	url = https://github.com/u-boot/u-boot
diff --git a/u-boot b/u-boot
new file mode 160000
index 0000000..1a66a77
--- /dev/null
+++ b/u-boot
@@ -0,0 +1 @@
+Subproject commit 1a66a7768af7e8106c2cd93a19f4013877fb85ae

From e282e27cce03682c7fd22f6128572bee06d7f402 Mon Sep 17 00:00:00 2001
From: Gulshan Singh <gsingh2011@gmail.com>
Date: Sun, 25 Feb 2024 19:52:46 -0800
Subject: [PATCH 2/4] Add u-boot build targets

---
 Makefile | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/Makefile b/Makefile
index 0e19731..1a16217 100644
--- a/Makefile
+++ b/Makefile
@@ -341,6 +341,46 @@ rootfs_clean:
 	$(SUDO) rm -f $(CPIO_FILE)
 	$(SUDO) rm -f $(ROOTFS)
 
+##
+## U-Boot
+##
+
+# Note: We're reusing the TARGET variable from the Linux build section
+
+UBOOT_SRC := $(ROOT_DIR)/u-boot
+UBOOT_OUT := $(OUT_DIR)/uboot/$(ARCH)
+UBOOT_CONFIG := $(UBOOT_OUT)/.config
+UBOOT_BIN := $(UBOOT_OUT)/u-boot.bin
+
+ifeq ($(ARCH),x86_64)
+  UBOOT_DEFCONFIG=qemu-x86_64_defconfig
+else ifeq ($(ARCH),i386)
+  UBOOT_DEFCONFIG=qemu-x86_defconfig
+else ifeq ($(ARCH),arm64)
+  UBOOT_DEFCONFIG=qemu_arm64_defconfig
+endif
+
+UBOOT_MAKE := \
+	PATH=$(CLANG_DIR)/bin:$(PATH) \
+	$(MAKE) \
+	-C $(UBOOT_SRC) \
+	HOSTCC=clang \
+	O=$(UBOOT_OUT) \
+	-j `nproc`
+
+.PHONY: uboot_defconfig
+uboot_defconfig $(UBOOT_CONFIG): | $(CLANG_DIR)
+	+ $(UBOOT_MAKE) $(UBOOT_DEFCONFIG)
+
+.PHONY: uboot
+uboot $(UBOOT_BIN): $(UBOOT_CONFIG) | $(CLANG_DIR)
+	+ $(UBOOT_MAKE) CROSS_COMPILE=$(TARGET)- CC=clang
+	cd $(UBOOT_SRC) && ./scripts/gen_compile_commands.py -d $(UBOOT_OUT)
+
+.PHONY: uboot_clean
+uboot_clean:
+	+ $(UBOOT_MAKE) mrproper
+
 ##
 ## Run QEMU
 ##

From 7bdb8ef1c2c27c866b04f83e81be5f015c1aa423 Mon Sep 17 00:00:00 2001
From: Gulshan Singh <gsingh2011@gmail.com>
Date: Sun, 25 Feb 2024 19:53:42 -0800
Subject: [PATCH 3/4] Run qemu with u-boot depending on UBOOT flag

---
 Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Makefile b/Makefile
index 1a16217..d62fa03 100644
--- a/Makefile
+++ b/Makefile
@@ -397,6 +397,7 @@ ECHR ?= 1
 ROOT ?= /dev/vda
 RW ?= rw
 KASLR ?= 0
+UBOOT ?= 0
 
 QEMU_KERNEL_CMDLINE := selinux=0
 
@@ -411,6 +412,10 @@ QEMU_ARGS := \
   -echr $(ECHR) \
   $(QEMU_EXTRA_ARGS)
 
+ifeq ($(UBOOT),1)
+  QEMU_ARGS += -bios $(UBOOT_BIN)
+endif
+
 ifneq ($(INITRD),)
   ifeq ($(INITRD),1)
     INITRD := $(CPIO_FILE)
@@ -456,6 +461,9 @@ endif
 QEMU_ARGS += -append "$(QEMU_KERNEL_CMDLINE) $(QEMU_EXTRA_KERNEL_CMDLINE)"
 
 RUN_DEPS := $(QEMU_KERNEL_IMAGE)
+ifeq ($(UBOOT),1)
+  RUN_DEPS += $(UBOOT_BIN)
+endif
 
 .PHONY: run
 run: $(RUN_DEPS) | $(SHARED_DIR)

From 01131da4ce08de65d2e1009c8aa57a412c75c07c Mon Sep 17 00:00:00 2001
From: Gulshan Singh <gsingh2011@gmail.com>
Date: Sun, 25 Feb 2024 19:55:20 -0800
Subject: [PATCH 4/4] Make some u-boot variables configurable

---
 Makefile | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index d62fa03..548b37d 100644
--- a/Makefile
+++ b/Makefile
@@ -347,17 +347,17 @@ rootfs_clean:
 
 # Note: We're reusing the TARGET variable from the Linux build section
 
-UBOOT_SRC := $(ROOT_DIR)/u-boot
-UBOOT_OUT := $(OUT_DIR)/uboot/$(ARCH)
+UBOOT_SRC ?= $(ROOT_DIR)/u-boot
+UBOOT_OUT ?= $(OUT_DIR)/uboot/$(ARCH)
 UBOOT_CONFIG := $(UBOOT_OUT)/.config
 UBOOT_BIN := $(UBOOT_OUT)/u-boot.bin
 
 ifeq ($(ARCH),x86_64)
-  UBOOT_DEFCONFIG=qemu-x86_64_defconfig
+  UBOOT_DEFCONFIG ?= qemu-x86_64_defconfig
 else ifeq ($(ARCH),i386)
-  UBOOT_DEFCONFIG=qemu-x86_defconfig
+  UBOOT_DEFCONFIG ?= qemu-x86_defconfig
 else ifeq ($(ARCH),arm64)
-  UBOOT_DEFCONFIG=qemu_arm64_defconfig
+  UBOOT_DEFCONFIG ?= qemu_arm64_defconfig
 endif
 
 UBOOT_MAKE := \