AndroidKernel.mk

   1 #Android makefile to build kernel as a part of Android Build
   2
   3 ifeq ($(KERNEL_DEFCONFIG),)
   4 $(error KERNEL_DEFCONFIG must be set as environment variable)
   5 endif
   6
   7 ifeq ($(INSTALLED_KERNEL_TARGET),)
   8 INSTALLED_KERNEL_TARGET := $(PRODUCT_OUT)/kernel
   9 INSTALLED_DTBOIMAGE_TARGET := $(PRODUCT_OUT)/dtbo.img
  10 BOARD_PREBUILT_DTBOIMAGE := $(PRODUCT_OUT)/prebuilt_dtbo.img
  11 INSTALLED_DTB_TARGET := $(PRODUCT_OUT)/dtb.img
  12 BOARD_MKBOOTIMG_ARGS += \
  13         --second $(INSTALLED_DTB_TARGET) \
  14         --second_offset 0
  15 endif
  16
  17 TARGET_KERNEL_ARCH := $(strip $(TARGET_KERNEL_ARCH))
  18 ifeq ($(TARGET_KERNEL_ARCH),)
  19 KERNEL_ARCH := arm64
  20 else
  21 KERNEL_ARCH := $(TARGET_KERNEL_ARCH)
  22 endif
  23
  24 ifeq ($(CROSS_COMPILE),)
  25 KERNEL_CROSS_COMPILE := aarch64-linux-android-
  26 else
  27 KERNEL_CROSS_COMPILE := $(CROSS_COMPILE)
  28 endif
  29
  30 ifeq ($(CLANG_TRIPLE),)
  31 CLANG_TRIPLE := aarch64-linux-gnu-
  32 else
  33 CLANG_TRIPLE := $(CLANG_TRIPLE)
  34 endif
  35
  36 ifeq ($(TARGET_PREBUILT_KERNEL),)
  37
  38 TARGET_KERNEL_SOURCE := kernel/$(TARGET_KERNEL)
  39 KERNEL_CONFIG := $(TARGET_KERNEL_SOURCE)/.config
  40 KERNEL_BOOT := $(TARGET_KERNEL_SOURCE)/arch/$(KERNEL_ARCH)/boot
  41 KERNEL_BIN := $(KERNEL_BOOT)/Image
  42 KERNEL_DTB_DIR := $(KERNEL_BOOT)/dts/exynos
  43 KERNEL_DTB := $(KERNEL_DTB_DIR)/exynos9610.dtb
  44 KERNEL_DTBO_CFG := $(KERNEL_DTB_DIR)/exynos9610_dtboimg.cfg
  45 MKDTIMG := $(HOST_OUT_EXECUTABLES)/mkdtimg
  46
  47 ifeq ($(KERNEL_DEFCONFIG),)
  48 $(error Kernel configuration not defined, cannot build kernel)
  49 else
  50
  51 ifeq ($(N_KERNEL_BUILD_THREAD),)
  52 N_KERNEL_BUILD_THREAD := 1
  53 endif
  54
  55 TARGET_PREBUILT_KERNEL := $(KERNEL_BIN)
  56
  57 .PHONY: remove-bins
  58 remove-bin:
  59         $(hide) echo "Clean Up prebuilts"
  60         rm -f $(KERNEL_CONFIG)
  61         rm -f $(KERNEL_BIN)
  62         rm -f $(KERNEL_DTB)
  63         rm -f $(INSTALLED_KERNEL_TARGET)
  64         rm -f $(INSTALLED_DTBOIMAGE_TARGET)
  65         rm -f $(INSTALLED_DTB_TARGET)
  66
  67 .PHONY: kernel
  68 kernel: $(KERNEL_BIN)
  69
  70 .PHONY: kernel-distclean
  71 kernel-distclean:
  72         $(MAKE) -C $(TARGET_KERNEL_SOURCE) ARCH=$(KERNEL_ARCH) CROSS_COMPILE=$(KERNEL_CROSS_COMPILE) distclean
  73
  74 $(KERNEL_CONFIG): remove-bins
  75         $(hide) echo "make $(KERNEL_DEFCONFIG)"
  76         $(MAKE) -C $(TARGET_KERNEL_SOURCE) ARCH=$(KERNEL_ARCH) CROSS_COMPILE=$(KERNEL_CROSS_COMPILE) $(KERNEL_DEFCONFIG)
  77
  78 $(KERNEL_BIN): $(KERNEL_CONFIG)
  79         $(hide) echo "Building kernel..."
  80         $(MAKE) -C $(TARGET_KERNEL_SOURCE) ARCH=$(KERNEL_ARCH) CROSS_COMPILE=$(KERNEL_CROSS_COMPILE) CLANG_TRIPLE=$(CLANG_TRIPLE) CC=clang -j$(N_KERNEL_BUILD_THREAD)
  81
  82 $(INSTALLED_KERNEL_TARGET): $(INSTALLED_DTBOIMAGE_TARGET)
  83         cp $(KERNEL_BIN) $(INSTALLED_KERNEL_TARGET)
  84         cp $(KERNEL_DTB) $(INSTALLED_DTB_TARGET)
  85
  86 $(BOARD_PREBUILT_DTBOIMAGE): $(MKDTIMG) $(KERNEL_DTBO_CFG) $(KERNEL_BIN)
  87         $(hide) echo "Building DTBOIMAGE..."
  88         ln -sf $(TARGET_KERNEL_SOURCE)/arch
  89         $(MKDTIMG) cfg_create $@ $(KERNEL_DTBO_CFG)
  90         rm -f arch
  91
  92 endif #TARGET_PREBUILT_KERNEL
  93 endif #KERNEL_DEFCONFIG