Add BOARD_CUSTOM_BOOTIMG_MK support

This is a combination of 2 commits.
This is the 1st commit message:

    Add BOARD_CUSTOM_BOOTIMG_MK support

    Simplified version of the previous implementation. Recovery's ramdisk
    is spun off from the main recovery target again to allow overriding
    just the image-generation step

    [mikeioannina]: Squash cm-13.0 changes and adapt to N

    Change-Id: I058d214f0cf2d05b7621b369ef1f8a983c3ac258

This is the commit message #2:

    build: Handle custom boot images properly

    When a pre-built image should be used, it should be stored in the
    target files zip so that it can be used with external signing
    processes.

    Original-Change-Id: I2661af9ac58af30bb9314b552775046d3abf44e0
    Change-Id: I10b3bd0bb33489b8ffb26d16d002f8dd6ff405ad

Change-Id: I058d214f0cf2d05b7621b369ef1f8a983c3ac258

core/Makefile

@@ -936,7 +936,8 @@ ifneq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
 ifeq ($(TARGET_BOOTIMAGE_USE_EXT2),true)
 $(error TARGET_BOOTIMAGE_USE_EXT2 is not supported anymore)
 
-else ifeq (true,$(BOARD_AVB_ENABLE)) # TARGET_BOOTIMAGE_USE_EXT2 != true
+else ifndef BOARD_CUSTOM_BOOTIMG_MK
+ifeq (true,$(BOARD_AVB_ENABLE)) # TARGET_BOOTIMAGE_USE_EXT2 != true
 
 $(INSTALLED_BOOTIMAGE_TARGET): $(MKBOOTIMG) $(AVBTOOL) $(INTERNAL_BOOTIMAGE_FILES) $(BOARD_AVB_BOOT_KEY_PATH)
 	$(call pretty,"Target boot image: $@")
@@ -1002,7 +1003,8 @@ bootimage-nodeps: $(MKBOOTIMG)
 	$(hide) $(MKBOOTIMG) $(INTERNAL_BOOTIMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $(INSTALLED_BOOTIMAGE_TARGET)
 	$(hide) $(call assert-max-image-size,$(INSTALLED_BOOTIMAGE_TARGET),$(BOARD_BOOTIMAGE_PARTITION_SIZE))
 
-endif # TARGET_BOOTIMAGE_USE_EXT2
+endif # PRODUCT_SUPPORTS_VBOOT
+endif # TARGET_BOOTIMAGE_USE_EXT2 / BOARD_CUSTOM_BOOTIMG_MK
 endif # BOARD_USES_RECOVERY_AS_BOOT
 
 else # TARGET_NO_KERNEL == "true"
@@ -1554,6 +1556,7 @@ IGNORE_RECOVERY_SEPOLICY := $(patsubst $(TARGET_RECOVERY_OUT)/%,--exclude=/%,$(r
 
 recovery_kernel := $(INSTALLED_KERNEL_TARGET) # same as a non-recovery system
 recovery_ramdisk := $(PRODUCT_OUT)/ramdisk-recovery.img
+recovery_uncompressed_ramdisk := $(PRODUCT_OUT)/ramdisk-recovery.cpio
 recovery_resources_common := $(call include-path-for, recovery)/res
 
 # Set recovery_density to a density bucket based on TARGET_SCREEN_DENSITY, PRODUCT_AAPT_PREF_CONFIG,
@@ -1826,9 +1829,7 @@ $(RECOVERY_INSTALL_OTA_KEYS): $(SOONG_ZIP) $(OTA_PUBLIC_KEYS) $(extra_keys)
 
 RECOVERYIMAGE_ID_FILE := $(PRODUCT_OUT)/recovery.id
 
-# $(1): output file
-define build-recoveryimage-target
-  # Making recovery image
+define build-recoveryramdisk
   $(hide) mkdir -p $(TARGET_RECOVERY_OUT)
   $(hide) mkdir -p $(TARGET_RECOVERY_ROOT_OUT)/sdcard $(TARGET_RECOVERY_ROOT_OUT)/tmp
   # Copying baseline ramdisk...
@@ -1859,7 +1860,11 @@ define build-recoveryimage-target
   $(hide) cp $(RECOVERY_INSTALL_OTA_KEYS) $(TARGET_RECOVERY_ROOT_OUT)/system/etc/security/otacerts.zip
   $(hide) ln -sf prop.default $(TARGET_RECOVERY_ROOT_OUT)/default.prop
   $(BOARD_RECOVERY_IMAGE_PREPARE)
-  $(hide) $(MKBOOTFS) -d $(TARGET_OUT) $(TARGET_RECOVERY_ROOT_OUT) | $(MINIGZIP) > $(recovery_ramdisk)
+endef
+
+RECOVERYIMAGE_ID_FILE := $(PRODUCT_OUT)/recovery.id
+# $(1): output file
+define build-recoveryimage-target
   $(if $(filter true,$(PRODUCT_SUPPORTS_VBOOT)), \
     $(hide) $(MKBOOTIMG) $(INTERNAL_RECOVERYIMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $(1).unsigned, \
     $(hide) $(MKBOOTIMG) $(INTERNAL_RECOVERYIMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $(1) --id > $(RECOVERYIMAGE_ID_FILE))
@@ -1917,6 +1922,8 @@ $(INSTALLED_BOOTIMAGE_TARGET): $(MKBOOTFS) $(MKBOOTIMG) $(MINIGZIP) \
 	    $(BOARD_RECOVERY_KERNEL_MODULES) \
 	    $(DEPMOD)
 	$(call pretty,"Target boot image from recovery: $@")
+	$(call build-recoveryramdisk)
+	$(hide) $(MKBOOTFS) -d $(TARGET_OUT) $(TARGET_RECOVERY_ROOT_OUT) | $(MINIGZIP) > $(recovery_ramdisk)
 	$(call build-recoveryimage-target, $@)
 endif # BOARD_USES_RECOVERY_AS_BOOT
 
@@ -1934,20 +1941,33 @@ ifdef BOARD_INCLUDE_DTB_IN_BOOTIMG
 $(INSTALLED_RECOVERYIMAGE_TARGET): $(INSTALLED_DTBIMAGE_TARGET)
 endif
 
-$(INSTALLED_RECOVERYIMAGE_TARGET): $(MKBOOTFS) $(MKBOOTIMG) $(MINIGZIP) \
+$(recovery_uncompressed_ramdisk): $(MKBOOTFS) $(ADBD) \
 	    $(INTERNAL_ROOT_FILES) \
 	    $(INSTALLED_RAMDISK_TARGET) \
 	    $(INSTALLED_BOOTIMAGE_TARGET) \
 	    $(INTERNAL_RECOVERYIMAGE_FILES) \
-	    $(recovery_initrc) $(recovery_sepolicy) $(recovery_kernel) \
+	    $(recovery_initrc) $(recovery_sepolicy) \
 	    $(INSTALLED_2NDBOOTLOADER_TARGET) \
 	    $(INSTALLED_RECOVERY_BUILD_PROP_TARGET) \
 	    $(recovery_resource_deps) \
 	    $(recovery_fstab) \
 	    $(RECOVERY_INSTALL_OTA_KEYS) \
 	    $(BOARD_RECOVERY_KERNEL_MODULES) \
 	    $(DEPMOD)
+	$(call build-recoveryramdisk)
+	@echo ----- Making uncompressed recovery ramdisk ------
+	$(hide) $(MKBOOTFS) $(TARGET_RECOVERY_ROOT_OUT) > $@
+
+$(recovery_ramdisk): $(MINIGZIP) \
+	$(recovery_uncompressed_ramdisk)
+	@echo ----- Making compressed recovery ramdisk ------
+	$(hide) $(MINIGZIP) < $(recovery_uncompressed_ramdisk) > $@
+
+ifndef BOARD_CUSTOM_BOOTIMG_MK
+$(INSTALLED_RECOVERYIMAGE_TARGET): $(MKBOOTIMG) $(recovery_ramdisk) $(recovery_kernel)
+	@echo ----- Making recovery image ------
 	$(call build-recoveryimage-target, $@)
+endif # BOARD_CUSTOM_BOOTIMG_MK
 
 ifdef RECOVERY_RESOURCE_ZIP
 $(RECOVERY_RESOURCE_ZIP): $(INSTALLED_RECOVERYIMAGE_TARGET) | $(ZIPTIME)
@@ -1959,6 +1979,8 @@ endif
 .PHONY: recoveryimage-nodeps
 recoveryimage-nodeps:
 	@echo "make $@: ignoring dependencies"
+	$(call build-recoveryramdisk)
+	$(hide) $(MKBOOTFS) -d $(TARGET_OUT) $(TARGET_RECOVERY_ROOT_OUT) | $(MINIGZIP) > $(recovery_ramdisk)
 	$(call build-recoveryimage-target, $(INSTALLED_RECOVERYIMAGE_TARGET))
 
 else # INSTALLED_RECOVERYIMAGE_TARGET not defined
@@ -1976,6 +1998,11 @@ ifneq ($(BOARD_NAND_SPARE_SIZE),)
 $(error MTD device is no longer supported and thus BOARD_NAND_SPARE_SIZE is deprecated.)
 endif
 
+ifdef BOARD_CUSTOM_BOOTIMG_MK
+include $(BOARD_CUSTOM_BOOTIMG_MK)
+endif
+
+
 # -----------------------------------------------------------------
 # the debug ramdisk, which is the original ramdisk plus additional
 # files: force_debuggable, adb_debug.prop and userdebug sepolicy.
@@ -3810,6 +3837,12 @@ endif # BOARD_USES_RECOVERY_AS_BOOT
 	$(hide) $(foreach t,$(INSTALLED_RADIOIMAGE_TARGET),\
 	            mkdir -p $(zip_root)/RADIO; \
 	            cp $(t) $(zip_root)/RADIO/$(notdir $(t));)
+ifdef BOARD_CUSTOM_BOOTIMG
+	@# Prebuilt boot images
+	$(hide) mkdir -p $(zip_root)/BOOTABLE_IMAGES
+	$(hide) $(ACP) $(INSTALLED_BOOTIMAGE_TARGET) $(zip_root)/BOOTABLE_IMAGES/
+	$(hide) $(ACP) $(INSTALLED_RECOVERYIMAGE_TARGET) $(zip_root)/BOOTABLE_IMAGES/
+endif
 ifdef BUILDING_SYSTEM_IMAGE
 	@# Contents of the system image
 	$(hide) $(call package_files-copy-root, \