From 8d5db3c24fb68928306cb424490af10e4a0fd3aa Mon Sep 17 00:00:00 2001
From: Christian Oder <myself5@carbonrom.org>
Date: Sat, 25 Nov 2017 16:52:17 +0100
Subject: [PATCH] kernel: Allow building dtbo.img

taimen uses the dtbo.img as an DTB Overlay in order to use the same defconfig for both, taimen and wahoo.
The dtbo.img is built with "make dtbo.img". Allow automatically building it when setting TARGET_NEEDS_DTBOIMAGE to true, or by manually calling make dtboimage.

Thanks to luca020400 for help with the kernel.mk logic

[raymanfx] Add AVB hash footer support

Change-Id: Iaddafaa98e3e84880462a2c35b899e3fea21e161
---
 build/tasks/kernel.mk | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/build/tasks/kernel.mk b/build/tasks/kernel.mk
index 426af62c..bfbafc54 100644
--- a/build/tasks/kernel.mk
+++ b/build/tasks/kernel.mk
@@ -396,6 +396,17 @@ alldefconfig: $(KERNEL_OUT_STAMP)
 
 endif # FULL_KERNEL_BUILD
 
+TARGET_PREBUILT_DTBO = $(PRODUCT_OUT)/dtbo/arch/$(KERNEL_ARCH)/boot/dtbo.img
+$(TARGET_PREBUILT_DTBO): $(AVBTOOL)
+	echo -e ${CL_GRN}"Building DTBO.img"${CL_RST}
+	$(MAKE) $(MAKE_FLAGS) -C $(KERNEL_SRC) O=$(PRODUCT_OUT)/dtbo ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) $(KERNEL_DEFCONFIG)
+	$(MAKE) $(MAKE_FLAGS) -C $(KERNEL_SRC) O=$(PRODUCT_OUT)/dtbo ARCH=$(KERNEL_ARCH) $(KERNEL_CROSS_COMPILE) $(KERNEL_CLANG_TRIPLE) $(KERNEL_CC) dtbo.img
+	$(AVBTOOL) add_hash_footer \
+		--image $@ \
+		--partition_size $(BOARD_DTBOIMG_PARTITION_SIZE) \
+		--partition_name dtbo $(INTERNAL_AVB_DTBO_SIGNING_ARGS) \
+		$(BOARD_AVB_DTBO_ADD_HASH_FOOTER_ARGS)
+
 ## Install it
 
 ifeq ($(NEEDS_KERNEL_COPY),true)
@@ -407,7 +418,19 @@ $(file) : $(KERNEL_BIN) | $(ACP)
 ALL_PREBUILT += $(INSTALLED_KERNEL_TARGET)
 endif
 
+ifeq ($(TARGET_NEEDS_DTBOIMAGE),true)
+file := $(INSTALLED_DTBOIMAGE_TARGET)
+ALL_PREBUILT += $(file)
+$(file) : $(TARGET_PREBUILT_DTBO) | $(ACP)
+	$(transform-prebuilt-to-target)
+
+ALL_PREBUILT += $(INSTALLED_DTBOIMAGE_TARGET)
+endif
+
 .PHONY: kernel
 kernel: $(INSTALLED_KERNEL_TARGET)
 
+.PHONY: dtbo
+dtbo: $(INSTALLED_DTBOIMAGE_TARGET)
+
 endif # TARGET_NO_KERNEL