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# Copyright (c) 2010-2012 Nest Labs, Inc.
# All rights reserved.
# This document is the property of Nest. It is considered
# confidential and proprietary information.
# This document may not be reproduced or transmitted in any form,
# in whole or in part, without the express written permission of
# Nest.
# Description:
# This file is the makefile for the Linux kernel.
include pre.mak
PackageSourceDir := $(LinuxSourcesPath)
PackageBuildConfig := $(call GenerateBuildPaths,.config)
PackageBuildMakefile := $(call GenerateBuildPaths,Makefile)
CleanPaths += $(PackageLicenseFile)
# Configuration
# Kernel default configuration is handled from most-specific to
# least-specific, as follows:
# Out-of-tree:
# 1) If configs/$(BuildProduct)/$(BuildConfig)_defconfig exists,
# it is used.
# 2) If configs/$(BuildProduct)/defconfig exists, it is used.
# 3) If configs/$(BuildConfig)_defconfig exists, it is used.
# 4) If configs/defconfig exists, it is used.
# In-tree:
# 5) If none of those exist, $(LinuxDefaultConfig) is used, which
# refers to an architecture- and/or board-specific default
# configuration.
# We go through this elaborate scheme because, once created, the
# kernel loses all association with it configuration file and the
# source it was created from. As a consequence, if the default
# configuration is edited, the kernel doesn't know about the
# change. This is especially problematic when changing branches or
# receiving updates to the default configuration and the kernel
# doesn't rebuild to reflect those changes.
# With this scheme, the user can edit .config as before. However, now
# if the default configuration is changed, out-of-tree only, .config
# is updated and the kernel will rebuild to reflect those changes.
PackageConfigDir := configs
PackageProjectConfig := $(PackageConfigDir)/defconfig
PackageConfigConfig := $(PackageConfigDir)/$(BuildConfig)_defconfig
PackageProductConfig := $(PackageConfigDir)/$(BuildProduct)/defconfig
PackageProductConfigConfig := $(PackageConfigDir)/$(BuildProduct)/$(BuildConfig)_defconfig
PackageMaybeProjectConfig := $(wildcard $(PackageProjectConfig))
PackageMaybeConfigConfig := $(wildcard $(PackageConfigConfig))
PackageMaybeProductConfig := $(wildcard $(PackageProductConfig))
PackageMaybeProductConfigConfig := $(wildcard $(PackageProductConfigConfig))
PackageMaybeConfig := $(if $(PackageMaybeProductConfigConfig),$(PackageProductConfigConfig),$(if $(PackageMaybeProductConfig),$(PackageProductConfig),$(if $(PackageMaybeConfigConfig),$(PackageConfigConfig),$(if $(PackageMaybeProjectConfig),$(PackageProjectConfig),))))
PackageSourceConfig := $(if $(PackageMaybeConfig),$(PackageMaybeConfig),)
ifeq ($(NL_KERNEL_VERSION), $(subst -,,$(NL_KERNEL_VERSION)))
PackageLocalVersion := ""
PackageLocalVersion := "-$(BuildVersion)"
# Specific products may want additional build targets beyond those
# produced by the linux build's 'all' target. Process and establish
# those.
LinuxAllTarget := all
LinuxBuildTargets := $(filter-out $(LinuxAllTarget),$(LinuxProductTargets)) $(LinuxAllTarget)
# For some architectures, the linux build requires u-boot's host
# 'mkimage' tool. Establish some paths and directories that will be
# used, if present, to help the linux build find it.
# Architecture-specific boot images that may need to be copied from
# the build to the result directory.
LinuxBootFolder = arch/$(LinuxProductArch)/boot
LinuxBootDir = $(call GenerateBuildPaths,$(LinuxBootFolder))
LinuxBootBuildPaths = $(addprefix $(LinuxBootDir)/,$(LinuxProductBootFiles))
LinuxKernelFiles = vmlinux
LinuxKernelFolder = .
LinuxKernelDir = $(call GenerateBuildPaths,$(LinuxKernelFolder))
LinuxKernelBuildPaths = $(addprefix $(call Slashify,$(LinuxKernelDir)),$(LinuxKernelFiles))
LinuxDtbUniqueFiles = $(sort $(LinuxDtbFiles))
LinuxDtbFolder = arch/$(LinuxProductArch)/boot/dts
LinuxDtbDir = $(call GenerateBuildPaths,$(LinuxDtbFolder))
LinuxDtbBuildPaths = $(addprefix $(call Slashify,$(LinuxDtbDir)),$(LinuxDtbUniqueFiles))
LinuxBuildPaths = $(LinuxBootBuildPaths) $(LinuxKernelBuildPaths) $(LinuxDtbBuildPaths)
LinuxResultPaths = $(call GenerateResultPaths,,$(notdir $(LinuxBuildPaths)))
LinuxConfigsDir = $(PackageSourceDir)/arch/arm/configs
# Common make arguments shared by all Linux target commands
LinuxCommonMakeArgs = \
-C $(PackageSourceDir) \
O=$(CURDIR)/$(BuildDirectory) \
ARCH=$(LinuxProductArch) \
INSTALL_HDR_PATH=$(ResultDirectory) \
INSTALL_MOD_PATH=$(ResultDirectory) \
LOCALVERSION="$(PackageLocalVersion)" \
$(if $(BuildVerbose),V=$(BuildVerbose)) \
all: $(PackageDefaultGoal)
# Generate the package license contents.
$(PackageLicenseFile): $(PackageSourceDir)/COPYING
# The Linux kernel build has no way of explicitly setting CC, LD,
# OBJCOPY, et al and instead relies on the value of
# CROSS_COMPILE. Consequently, we have to ensure that 'ToolBinDir' is
# in 'PATH' so that the kernel build infrastructure can find
# $(CROSS_COMPILE)gcc, $(CROSS_COMPILE)ld, et al.
# Additionally, per the above, add the path to U-Boot's 'mkimage' if
# the variable is defined.
PATH := $(PATH):$(ToolBinDir)
# Generate the Linux build configuration and make file
# We are either copying and out-of-tree configuration or using an
# in-tree default (see above).
# $(PackageBuildConfig): help-defconfig
ifeq ($(PackageSourceConfig),)
DefconfigBasename=$(subst _defconfig,,$(LinuxDefaultConfig))
$(PackageBuildConfig): $(LinuxConfigsDir)/$(LinuxDefaultConfig) $(ConfigFragment) | $(BuildDirectory)
$(Echo) "The default Linux build configuration is \"$(LinuxDefaultConfig)\"."
$(Verbose)$(MAKE) $(LinuxCommonMakeArgs) $(LinuxDefaultConfig)
$(Echo) "Applying config fragment \"$(notdir $(ConfigFragment))\"."
$(Verbose)$(PackageSourceDir)/scripts/kconfig/ -O $(BuildDirectory) -m $(@) $(ConfigFragment)
$(Echo) "Setting unspecified options to defaults"
$(Verbose) yes " " | $(MAKE) $(LinuxCommonMakeArgs) oldconfig
$(Verbose)scripts/ $(@) $(ConfigFragment)
$(PackageBuildConfig): $(PackageSourceConfig) | $(PackageSourceDir) $(BuildDirectory)
$(Echo) "The default Linux build configuration is \"$(PackageSourceConfig)\"."
# Configure the source for building.
.PHONY: configure
configure: $(PackageBuildConfig) | $(BuildDirectory)
# Build the source.
.PHONY: build
build: configure | $(BuildDirectory)
$(Verbose)$(MAKE) $(LinuxCommonMakeArgs) $(LinuxProductMakeArgs) $(LinuxBuildTargets) $(LinuxDtbUniqueFiles)
$(Verbose)touch $(call GenerateBuildPaths,$(@))
# Stage the build to a temporary installation area.
.PHONY: stage
stage: stage-boot stage-modules stage-headers
.PHONY: headers
headers: stage-headers
.PHONY: stage-boot
stage-boot: $(LinuxResultPaths)
.PHONY: stage-modules
stage-modules: build | $(ResultDirectory) $(BuildDirectory)
$(Verbose)flock -w 15 $(ResultDirectory)/modules-install-lock -c '$(MAKE) $(LinuxCommonMakeArgs) modules_install'
stage-headers: configure | $(ResultDirectory) $(BuildDirectory)
$(Verbose)$(MAKE) $(LinuxCommonMakeArgs) headers_install
$(Verbose)$(MAKE) $(LinuxCommonMakeArgs) $(*)
$(LinuxBuildPaths): build
$(ResultDirectory)/%: $(LinuxBootDir)/% | $(ResultDirectory)
$(ResultDirectory)/%: $(LinuxKernelDir)/% | $(ResultDirectory)
$(ResultDirectory)/%: $(LinuxDtbDir)/% | $(ResultDirectory)
$(Verbose)$(RM) $(RMFLAGS) -r $(BuildDirectory)
$(Verbose)$(RM) $(RMFLAGS) -r $(ResultDirectory)
.PHONY: help help-defconfig
help: help-defconfig
include post.mak