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Commit d8ee91f1 authored by Ricardo Cerqueira's avatar Ricardo Cerqueira Committed by Ricardo Cerqueira
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build: Inline kernel building as a buildtime task 

Kernel image integration is now done in the build system. The
"one true way" of doing this is to download the kernel source
into kernel/TARGET_BOOTLOADER_NAME (by usage of the cm.dependencies
mechanism or otherwise), and defining the TARGET_KERNEL_CONFIG
variable in the device's BoardConfig makefile

If the kernel's location doesn't match the automagic location
(multi-device kernel source, for instance), TARGET_KERNEL_SOURCE
can be used to specify a kernel path (i.e.,
"TARGET_KERNEL_SOURCE := kernel/shared-whatever")

If the device requires out-of-kernel-tree modules to be built,
the TARGET_KERNEL_MODULES variable can be used, pointing to a
_make target_ that will build and install such modules. Definition
of such a target is the device author's responsibility, the only
restriction is that it is a normal makefile recipe (example
below)

Optionally (or as an alternative), a prebuilt binary can also be
defined at BoardConfig, by usage of the TARGET_PREBUILT_KERNEL
variable. This binary will be used if the kernel source is absent
(or undefined).

A minimal BoardConfig.mk should look something like this:

TARGET_KERNEL_CONFIG := cyanogenmod_<device>_defconfig
TARGET_PREBUILT_KERNEL := device/<vendor>/<device>/kernel

To include, for example, the TI WLAN modules, this can be used:

-----------------------------
TIWLAN_MODULES:
       make -C hardware/ti/wlan/wl1283/platforms/os/linux/ KERNEL_DIR=$(KERNEL_OUT) ARCH="arm" CROSS_COMPILE="arm-eabi-" TNETW=1273 RANDOM_MAC=n REPORT_LOG=n
       mv hardware/ti/wlan/wl1283/platforms/os/linux/tiwlan_drv.ko $(KERNEL_MODULES_OUT)
       make -C hardware/ti/wlan/wl1283_softAP/platforms/os/linux/ KERNEL_DIR=$(KERNEL_OUT) ARCH="arm" CROSS_COMPILE="arm-eabi-" TNETW=1273 REPORT_LOG=n
       mv hardware/ti/wlan/wl1283_softAP/platforms/os/linux/tiap_drv.ko $(KERNEL_MODULES_OUT)

TARGET_KERNEL_MODULES := TIWLAN_MODULES
---------------------------

Change-Id: I8634fa4c788a42dc6f62e62ca170825b66db126a
parent 2683a9d5

core/tasks/kernel.mk

0 → 100644
+129 −0
Original line number Diff line number Diff line 
#Android makefile to build kernel as a part of Android Build



## Externally influenced variables

# kernel location - optional, defaults to kernel/<board>

TARGET_KERNEL_SOURCE ?= kernel/$(TARGET_BOOTLOADER_BOARD_NAME)

KERNEL_SRC := $(TARGET_KERNEL_SOURCE)

# kernel configuration - mandatory

KERNEL_DEFCONFIG := $(TARGET_KERNEL_CONFIG)



## Internal variables

KERNEL_OUT := $(ANDROID_BUILD_TOP)/$(TARGET_OUT_INTERMEDIATES)/KERNEL_OBJ

KERNEL_CONFIG := $(KERNEL_OUT)/.config



ifeq ($(BOARD_USES_UBOOT),true)

	TARGET_PREBUILT_INT_KERNEL := $(KERNEL_OUT)/arch/arm/boot/uImage

	TARGET_PREBUILT_INT_KERNEL_TYPE := uImage

else

	TARGET_PREBUILT_INT_KERNEL := $(KERNEL_OUT)/arch/arm/boot/zImage

	TARGET_PREBUILT_INT_KERNEL_TYPE := zImage

endif



ifeq "$(wildcard $(KERNEL_SRC) )" ""

    ifneq ($(TARGET_PREBUILT_KERNEL),)

        $(warning ***************************************************************)

        $(warning * Using prebuilt kernel binary instead of source              *)

        $(warning * THIS IS DEPRECATED, AND WILL BE DISCONTINUED                *)

        $(warning * Please configure your device to download the kernel         *)

        $(warning * source repository to $(KERNEL_SRC))

        $(warning * See http://wiki.cyanogenmod.com/wiki/Integrated_kernel_building)

        $(warning * for more information                                        *)

        $(warning ***************************************************************)

        FULL_KERNEL_BUILD := false

        KERNEL_BIN := $(TARGET_PREBUILT_KERNEL)

    else

        $(warning ***************************************************************)

        $(warning *                                                             *)

        $(warning * No kernel source found, and no fallback prebuilt defined.   *)

        $(warning * Please make sure your device is properly configured to      *)

        $(warning * download the kernel repository to $(KERNEL_SRC))

        $(warning * and add the TARGET_KERNEL_CONFIG variable to AndroidBoard.mk*)

        $(warning *                                                             *)

        $(warning * As an alternative, define the TARGET_PREBUILT_KERNEL        *)

        $(warning * variable with the path to the prebuilt binary kernel image  *)

        $(warning * in your AndroidBoard.mk file                                *)

        $(warning *                                                             *)

        $(warning ***************************************************************)

        $(error "NO KERNEL")

    endif

else

    ifeq ($(TARGET_KERNEL_CONFIG),)

        $(warning **********************************************************)

        $(warning * Kernel source found, but no configuration was defined  *)

        $(warning * Please add the TARGET_KERNEL_CONFIG variable to your   *)

        $(warning * AndroidBoard.mk file                                   *)

        $(warning **********************************************************)

        $(error "NO KERNEL CONFIG")

    else

        #$(info Kernel source found, building it)

        FULL_KERNEL_BUILD := true

        ifeq ($(TARGET_USES_UNCOMPRESSED_KERNEL),true)

        $(info Using uncompressed kernel)

            KERNEL_BIN := $(KERNEL_OUT)/piggy

        else

            KERNEL_BIN := $(TARGET_PREBUILT_INT_KERNEL)

        endif

    endif

endif



ifeq ($(FULL_KERNEL_BUILD),true)



KERNEL_HEADERS_INSTALL := $(KERNEL_OUT)/usr

KERNEL_MODULES_INSTALL := system

KERNEL_MODULES_OUT := $(TARGET_OUT)/lib/modules



define mv-modules

    mdpath=`find $(KERNEL_MODULES_OUT) -type f -name modules.dep`;\

    if [ "$$mdpath" != "" ];then\

        mpath=`dirname $$mdpath`;\

        ko=`find $$mpath/kernel -type f -name *.ko`;\

        for i in $$ko; do mv $$i $(KERNEL_MODULES_OUT)/; done;\

    fi

endef



define clean-module-folder

    mdpath=`find $(KERNEL_MODULES_OUT) -type f -name modules.dep`;\

    if [ "$$mdpath" != "" ];then\

        mpath=`dirname $$mdpath`; rm -rf $$mpath;\

    fi

endef



ifeq ($(TARGET_KERNEL_MODULES),)

    TARGET_KERNEL_MODULES := no-external-modules

endif



$(KERNEL_OUT):

	mkdir -p $(KERNEL_OUT)

	mkdir -p $(KERNEL_MODULES_OUT)



$(KERNEL_CONFIG): $(KERNEL_OUT)

	$(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=arm CROSS_COMPILE=arm-eabi- $(KERNEL_DEFCONFIG)



$(KERNEL_OUT)/piggy : $(TARGET_PREBUILT_INT_KERNEL)

	$(hide) gunzip -c $(KERNEL_OUT)/arch/arm/boot/compressed/piggy.gzip > $(KERNEL_OUT)/piggy



TARGET_KERNEL_BINARIES: $(KERNEL_OUT) $(KERNEL_CONFIG) $(KERNEL_HEADERS_INSTALL)

	$(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=arm CROSS_COMPILE=arm-eabi- $(TARGET_PREBUILT_INT_KERNEL_TYPE)

	$(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=arm CROSS_COMPILE=arm-eabi- modules

	$(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) INSTALL_MOD_PATH=../../$(KERNEL_MODULES_INSTALL) ARCH=arm CROSS_COMPILE=arm-eabi- modules_install



$(TARGET_KERNEL_MODULES): TARGET_KERNEL_BINARIES



$(TARGET_PREBUILT_INT_KERNEL): $(TARGET_KERNEL_MODULES)

	$(mv-modules)

	$(clean-module-folder)



$(KERNEL_HEADERS_INSTALL): $(KERNEL_OUT) $(KERNEL_CONFIG)

	$(MAKE) -C $(KERNEL_SRC) O=$(KERNEL_OUT) ARCH=arm CROSS_COMPILE=arm-eabi- headers_install



endif # FULL_KERNEL_BUILD



## Install it



file := $(INSTALLED_KERNEL_TARGET)

ALL_PREBUILT += $(file)

$(file) : $(KERNEL_BIN) | $(ACP)

	$(transform-prebuilt-to-target)



ALL_PREBUILT += $(INSTALLED_KERNEL_TARGET)