###############################################################################
#
# Linux kernel target
#
###############################################################################
LINUX_VERSION=$(call qstrip,$(BR2_LINUX_KERNEL_VERSION))

# Compute LINUX_SOURCE and LINUX_SITE from the configuration
ifeq ($(LINUX_VERSION),custom)
LINUX_TARBALL:=$(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION))
LINUX_SITE:=$(dir $(LINUX_TARBALL))
LINUX_SOURCE:=$(notdir $(LINUX_TARBALL))
else
LINUX_SOURCE:=linux-$(LINUX_VERSION).tar.bz2
LINUX_SITE:=$(BR2_KERNEL_MIRROR)/linux/kernel/v2.6/
endif

LINUX_DIR:=$(BUILD_DIR)/linux-$(LINUX_VERSION)
LINUX_PATCH=$(call qstrip,$(BR2_LINUX_KERNEL_PATCH))

LINUX_MAKE_FLAGS = \
	HOSTCC="$(HOSTCC)" \
	HOSTCFLAGS="$(HOSTCFLAGS)" \
	ARCH=$(KERNEL_ARCH) \
	INSTALL_MOD_PATH=$(TARGET_DIR) \
	CROSS_COMPILE="$(CCACHE) $(TARGET_CROSS)" \
	LZMA="$(LZMA)"

# Get the real Linux version, which tells us where kernel modules are
# going to be installed in the target filesystem.
LINUX_VERSION_PROBED = $(shell $(MAKE) $(LINUX_MAKE_FLAGS) -C $(LINUX_DIR) --no-print-directory -s kernelrelease)

ifeq ($(BR2_LINUX_KERNEL_IMAGE_TARGET_CUSTOM),y)
LINUX_IMAGE_NAME=$(call qstrip,$(BR2_LINUX_KERNEL_IMAGE_TARGET_NAME))
else
ifeq ($(BR2_LINUX_KERNEL_UIMAGE),y)
ifeq ($(KERNEL_ARCH),blackfin)
# a uImage, but with a different file name
LINUX_IMAGE_NAME=vmImage
else
LINUX_IMAGE_NAME=uImage
endif
LINUX_DEPENDENCIES+=host-uboot-mkimage
else ifeq ($(BR2_LINUX_KERNEL_BZIMAGE),y)
LINUX_IMAGE_NAME=bzImage
else ifeq ($(BR2_LINUX_KERNEL_ZIMAGE),y)
LINUX_IMAGE_NAME=zImage
else ifeq ($(BR2_LINUX_KERNEL_VMLINUX_BIN),y)
LINUX_IMAGE_NAME=vmlinux.bin
else ifeq ($(BR2_LINUX_KERNEL_VMLINUX),y)
LINUX_IMAGE_NAME=vmlinux
endif
endif

# Compute the arch path, since i386 and x86_64 are in arch/x86 and not
# in arch/$(KERNEL_ARCH). Even if the kernel creates symbolic links
# for bzImage, arch/i386 and arch/x86_64 do not exist when copying the
# defconfig file.
ifeq ($(KERNEL_ARCH),i386)
KERNEL_ARCH_PATH=$(LINUX_DIR)/arch/x86
else ifeq ($(KERNEL_ARCH),x86_64)
KERNEL_ARCH_PATH=$(LINUX_DIR)/arch/x86
else
KERNEL_ARCH_PATH=$(LINUX_DIR)/arch/$(KERNEL_ARCH)
endif

ifeq ($(BR2_LINUX_KERNEL_VMLINUX),y)
LINUX_IMAGE_PATH=$(LINUX_DIR)/$(LINUX_IMAGE_NAME)
else
ifeq ($(KERNEL_ARCH),avr32)
LINUX_IMAGE_PATH=$(KERNEL_ARCH_PATH)/boot/images/$(LINUX_IMAGE_NAME)
else
LINUX_IMAGE_PATH=$(KERNEL_ARCH_PATH)/boot/$(LINUX_IMAGE_NAME)
endif
endif # BR2_LINUX_KERNEL_VMLINUX

# Download
$(LINUX_DIR)/.stamp_downloaded:
	@$(call MESSAGE,"Downloading kernel")
	$(call DOWNLOAD,$(LINUX_SITE),$(LINUX_SOURCE))
	$(foreach patch,$(filter ftp://% http://%,$(LINUX_PATCH)),\
		$(call DOWNLOAD,$(dir $(patch)),$(notdir $(patch)))$(sep))
	mkdir -p $(@D)
	touch $@

# Extraction
$(LINUX_DIR)/.stamp_extracted: $(LINUX_DIR)/.stamp_downloaded
	@$(call MESSAGE,"Extracting kernel")
	mkdir -p $(@D)
	$(Q)$(INFLATE$(suffix $(LINUX_SOURCE))) $(DL_DIR)/$(LINUX_SOURCE) | \
		tar -C $(@D) $(TAR_STRIP_COMPONENTS)=1 $(TAR_OPTIONS) -
	$(Q)touch $@

# Patch
$(LINUX_DIR)/.stamp_patched: $(LINUX_DIR)/.stamp_extracted
	@$(call MESSAGE,"Patching kernel")
	for p in $(LINUX_PATCH) ; do \
		if echo $$p | grep -q -E "^ftp://|^http://" ; then \
			toolchain/patch-kernel.sh $(@D) $(DL_DIR) `basename $$p` ; \
		elif test -d $$p ; then \
			toolchain/patch-kernel.sh $(@D) $$p linux-\*.patch ; \
		else \
			toolchain/patch-kernel.sh $(@D) `dirname $$p` `basename $$p` ; \
		fi \
	done
	$(Q)touch $@


# Configuration
$(LINUX_DIR)/.stamp_configured: $(LINUX_DIR)/.stamp_patched
	@$(call MESSAGE,"Configuring kernel")
ifeq ($(BR2_LINUX_KERNEL_USE_DEFCONFIG),y)
	$(TARGET_MAKE_ENV) $(MAKE1) $(LINUX_MAKE_FLAGS) -C $(@D) $(call qstrip,$(BR2_LINUX_KERNEL_DEFCONFIG))_defconfig
else ifeq ($(BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG),y)
	cp $(BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE) $(KERNEL_ARCH_PATH)/configs/buildroot_defconfig
	$(TARGET_MAKE_ENV) $(MAKE1) $(LINUX_MAKE_FLAGS) -C $(@D) buildroot_defconfig
	rm $(KERNEL_ARCH_PATH)/configs/buildroot_defconfig
endif
ifeq ($(BR2_ARM_EABI),y)
	$(call KCONFIG_ENABLE_OPT,CONFIG_AEABI,$(@D)/.config)
else
	$(call KCONFIG_DISABLE_OPT,CONFIG_AEABI,$(@D)/.config)
endif
ifeq ($(BR2_TARGET_ROOTFS_INITRAMFS),y)
	# As the kernel gets compiled before root filesystems are
	# built, we create a fake initramfs file list. It'll be
	# replaced later by the real list, and the kernel will be
	# rebuilt using the linux26-rebuild-with-initramfs target.
	touch $(BINARIES_DIR)/rootfs.initramfs
	$(call KCONFIG_ENABLE_OPT,CONFIG_BLK_DEV_INITRD,$(@D)/.config)
	$(call KCONFIG_SET_OPT,CONFIG_INITRAMFS_SOURCE,\"$(BINARIES_DIR)/rootfs.initramfs\",$(@D)/.config)
	$(call KCONFIG_SET_OPT,CONFIG_INITRAMFS_ROOT_UID,0,$(@D)/.config)
	$(call KCONFIG_SET_OPT,CONFIG_INITRAMFS_ROOT_GID,0,$(@D)/.config)
	$(call KCONFIG_DISABLE_OPT,CONFIG_INITRAMFS_COMPRESSION_NONE,$(@D)/.config)
	$(call KCONFIG_ENABLE_OPT,CONFIG_INITRAMFS_COMPRESSION_GZIP,$(@D)/.config)
endif
ifneq ($(BR2_ROOTFS_DEVICE_CREATION_STATIC),y)
	$(call KCONFIG_ENABLE_OPT,CONFIG_DEVTMPFS,$(@D)/.config)
	$(call KCONFIG_ENABLE_OPT,CONFIG_DEVTMPFS_MOUNT,$(@D)/.config)
endif
ifeq ($(BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_MDEV),y)
	$(call KCONFIG_SET_OPT,CONFIG_UEVENT_HELPER_PATH,\"/sbin/mdev\",$(@D)/.config)
endif
	$(TARGET_MAKE_ENV) $(MAKE) $(LINUX_MAKE_FLAGS) -C $(@D) oldconfig
	$(Q)touch $@

# Compilation. We make sure the kernel gets rebuilt when the
# configuration has changed.
$(LINUX_DIR)/.stamp_compiled: $(LINUX_DIR)/.stamp_configured $(LINUX_DIR)/.config
	@$(call MESSAGE,"Compiling kernel")
	$(TARGET_MAKE_ENV) $(MAKE) $(LINUX_MAKE_FLAGS) -C $(@D) $(LINUX_IMAGE_NAME)
	@if grep -q "CONFIG_MODULES=y" $(@D)/.config; then 	\
		$(TARGET_MAKE_ENV) $(MAKE) $(LINUX_MAKE_FLAGS) -C $(@D) modules ;	\
	fi
	$(Q)touch $@

# Installation
$(LINUX_DIR)/.stamp_installed: $(LINUX_DIR)/.stamp_compiled
	@$(call MESSAGE,"Installing kernel")
ifeq ($(BR2_LINUX_KERNEL_INSTALL_TARGET),y)
	install -m 0644 -D $(LINUX_IMAGE_PATH) $(TARGET_DIR)/boot/$(LINUX_IMAGE_NAME)
endif
	cp $(LINUX_IMAGE_PATH) $(BINARIES_DIR)
	# Install modules and remove symbolic links pointing to build
	# directories, not relevant on the target
	@if grep -q "CONFIG_MODULES=y" $(@D)/.config; then 	\
		$(TARGET_MAKE_ENV) $(MAKE1) $(LINUX_MAKE_FLAGS) -C $(@D) 		\
			DEPMOD="$(HOST_DIR)/usr/sbin/depmod" modules_install ;		\
		rm -f $(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED)/build ;		\
		rm -f $(TARGET_DIR)/lib/modules/$(LINUX_VERSION_PROBED)/source ;	\
	fi
	$(Q)touch $@

linux linux26: host-module-init-tools $(LINUX_DEPENDENCIES) $(LINUX_DIR)/.stamp_installed

linux-menuconfig linux-xconfig linux-gconfig linux-nconfig linux26-menuconfig linux26-xconfig linux26-gconfig linux26-nconfig: dirs $(LINUX_DIR)/.stamp_configured
	$(MAKE) $(LINUX_MAKE_FLAGS) -C $(LINUX_DIR) \
		$(subst linux-,,$(subst linux26-,,$@))

# Support for rebuilding the kernel after the initramfs file list has
# been generated in $(BINARIES_DIR)/rootfs.initramfs.
$(LINUX_DIR)/.stamp_initramfs_rebuilt: $(LINUX_DIR)/.stamp_installed $(BINARIES_DIR)/rootfs.initramfs
	@$(call MESSAGE,"Rebuilding kernel with initramfs")
	# Remove the previously generated initramfs which was empty,
	# to make sure the kernel will actually regenerate it.
	$(RM) -f $(@D)/usr/initramfs_data.cpio*
	# Build the kernel.
	$(TARGET_MAKE_ENV) $(MAKE) $(LINUX_MAKE_FLAGS) -C $(@D) $(LINUX_IMAGE_NAME)
	# Copy the kernel image to its final destination
	cp $(LINUX_IMAGE_PATH) $(BINARIES_DIR)
	$(Q)touch $@

# The initramfs building code must make sure this target gets called
# after it generated the initramfs list of files.
linux-rebuild-with-initramfs linux26-rebuild-with-initramfs: $(LINUX_DIR)/.stamp_initramfs_rebuilt

ifeq ($(BR2_LINUX_KERNEL),y)
TARGETS+=linux
endif

# Checks to give errors that the user can understand
ifeq ($(filter source,$(MAKECMDGOALS)),)
ifeq ($(BR2_LINUX_KERNEL_USE_DEFCONFIG),y)
ifeq ($(call qstrip,$(BR2_LINUX_KERNEL_DEFCONFIG)),)
$(error No kernel defconfig name specified, check your BR2_LINUX_KERNEL_DEFCONFIG setting)
endif
endif

ifeq ($(BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG),y)
ifeq ($(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE)),)
$(error No kernel configuration file specified, check your BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE setting)
endif
endif

endif