Building Android and Linux Kernel for Nexus One[转载]

原文地址：

http://randomizedsort.blogspot.com/2010/08/building-android-and-linux-kernel-for.html

System Requirements

Google's Android build system only supports Linux (Ubuntu) and Mac OS. Examples below all use Ubuntu. The two most important tools from the Android SDK are "adb" and "fastboot". But "fastboot" is not available in the Linux distribution of the SDK. We will build it from the source.

FortheImpatientIfyoualreadyknoweverything,youcanfindrequiredstepsforNexusOneinsummaryfromthisthread.Butyourmileagemayvary.

CompilingAndroidPlatform

VCSGoogleusesGittoastheVCSforbothAndroidanditsownLinuxkernel.TheirsourceispublishedonGitwebathttp://android.git.kernel.org/.

HereareacoupleofGittutorialsforCVSusers:

Cogito-CVSCrashCourse

CVStogitTransitionGuide

GooglepublishesitsrepotoolformanagingAndroidsource.RepodoesnotseemtoworkontheLinuxKernelsourcetreethough.

CHECKING-OUTSOURCE1.CreatetwoseparatedirectoriestoholdAndoridplatformanditsLinuxkernelsourcetrees:

laptop-2:~/myandroid$ ls
kernel  platform

2. Next, change to the platform directory and and initialize the repo.

$ cd platform
$HOME repo init -u git://android.git.kernel.org/platform/manifest.git -b froyo

The branch name "froyo" can be found on the git web at:

http://android.git.kernel.org/?p=platform/manifest.git;a=summary

Remotebranchnamescanbefoundinthe"heads"sectiononthatwebpage.

3. Sync with the source.

$HOME repo sync

This makes "~/myandroid/platform" the root of the platform source tree. We will use "platform" for short in the following examples.

BUILDING

1. Set up the build environment from the root of the source tree as the following:

$ . build/envsetup.sh

2. If building a phone-specific Android, then build adb first. Otherwise, skip to step six. But note that you can only build a generic Android if you skip device steps. If you flash a generic Android image to your phone, your phone will not even get a radio signal. Nor will you be able to use any buttons on the device. So skip this step only if you just want to play with the emulator.At the root of the source tree:

$ make adb

3. Make adb available on the path.

$ export $HOME/myandroid/platform/out/host/linux-x86/bin:$PATH
$ which adb
$HOME/myandroid/platform/out/host/linux-x86/bin/adb

4. We need to extract device specific files from Nexus One. Connect the phone to the laptop using the USB cable. The phone needs to be powered on. If the phone has not been set to USB debugging. Set it at:Settings-->Applications-->Development-->USBdebuggingThencheckthatadbcanseethedevice.

/out/host/linux-x86/bin$ sudo ./adb devices
[sudo] password for userone: 
* daemon not running. starting it now *
* daemon started successfully *
List of devices attached 
HTXXXXXXXXX device

5. Google Nexus One is HTC Passion. So we now run the Passion-specific extraction script under the "device/htc/passion" directory. 

NotethatthedevicefilesmustbeextractedfromaAndroiddevicethatmatchestoyourbuild.HereweextractfromaNexusOnewith2.2updatebecausewearegoingtobuildtheFroyobranchofthecode.

$ cd device/htc/passion
/device/htc/passion$./extract-files.sh

Note that adb must be on the path in order for the extraction script to succeed. The extraction script will pull HTC proprietary files from the device and store them under "vendor/htc/passion".

/vendor/htc/passion/proprietary$ ls
01_qcomm_omx.cfg        libEGL_adreno200.so        libOmxVdec.so
AdieHWCodecSetting.csv  libGLESv1_CM_adreno200.so  libOmxVidEnc.so
akmd                    libGLESv2_adreno200.so     libopencorehw.so
AudioBTID.csv           libgps.so                  libq3dtools_adreno200.so
bcm4329.hcd             libgsl.so                  libqcomm_omx.so
default.acdb            libhtc_acoustic.so         libstagefrighthw.so
default_att.acdb        libhtc_ril.so              mm-venc-omx-test
default_france.acdb     liblvmxipc.so              parse_radio_log
fw_bcm4329_apsta.bin    libmm-omxcore.so           vpimg
fw_bcm4329.bin          liboemcamera.so            yamato_pfp.fw
libcamera.so            libOmxCore.so              yamato_pm4.fw

6. Change back to the root of the source tree and use "lunch" to set up appropriate build environment variables.

$ lunch

You're building on Linux

Lunch menu... pick a combo:
     1. generic-eng
     2. simulator
     3. full_dream-userdebug
     4. full_passion-userdebug
     5. full_sapphire-userdebug

Which would you like? [generic-eng] 4

The "generic-eng" build option will allow you to build an Android that is not device specific. But then you can't really use a generic Android image on a real phone because the generic image does not know how to use device-specific features such as buttons and camera. Nor can the generic image read radio signals. Therefore, the generic-eng build is only useful for emulator purpose. The main difference between generic-eng and userdebug is if the file system is read-write or read-only by default. We will select "full_passion-user-debug" here because we want to flash our images to the device.7. Build the Android platform from the root of the source tree.

$ make

Note: When building "full_passion-userdebug" the first time, I hit a compiler error on "librpc.so not found" which caused references in HTC's proprietary libgps to fail compiling. After googling a solution, I found the following workaround:

$ mm librpc
$ make

Do not run "make clean" when performing the two steps above. I have since checked out the froyo branch many times and have never encountered this problem again.8. Inspect build output.

Thebuildartifactsarelocatedundertheoutsubdirectory.

$ ls out
casecheck.txt  CaseCheck.txt  debug  host  target  tmp  versions_checked.mk

The Android tools for Linux/X86 are located under "host". The device images are under "target".

Compiling Linux Kernel for ARM

CHECKING-OUT SOURCEI used Git instead of Google's repo for kernel building.

1.ClonetheMSMfamilyofthekerneltreefromtheAndroidGittoaworkingdirectory.AsofJuly2010,allHTCAndroidphonesuseQualcomm'sMSMfamilyoftheCDMA/GSM/UMTSchipsets.NexusOneisnoexception.

userone@userone-laptop-2:~/myandroid/kernel$ git clone git://android.git.kernel.org/kernel/msm.git .

If building the emulator kernel, use "git://android.git.kernel.org/kernel/common.git" instead.2. Check out the latest 2.6.32 kernel branch for Nexus One.

userone@userone-laptop-2:~/myandroid/kernel$ git checkout --track -b userone-msm-2.6.32-nexusonec remotes/origin/android-msm-2.6.32-nexusonec

When the check out is done, you can use git to verify the branch info.

userone@userone-laptop-2:~/myandroid/kernel$ git branch -a
  android-msm-2.6.27
  userone-msm-2.6.32
* userone-msm-2.6.32-nexusonec
  remotes/origin/HEAD -> origin/android-msm-2.6.27
  remotes/origin/android-msm-2.6.25
  remotes/origin/android-msm-2.6.27
  remotes/origin/android-msm-2.6.29
  remotes/origin/android-msm-2.6.29-donut
  remotes/origin/android-msm-2.6.29-nexusone
  remotes/origin/android-msm-2.6.32
  remotes/origin/android-msm-2.6.32-nexusonec
  remotes/origin/android-msm-htc-2.6.25
  remotes/origin/android-msm8k-2.6.29
  remotes/origin/msm-2.6.25

The root of the kernel tree is now "userone@userone-laptop-2:~/myandroid/kernel". 

BUILDING

1. Setup the build environment using the "build/envsetup.sh" script as shown in the platform build. This sets up important cross compiling environment variables for ARM build.

2.Setupenvironmentvariablesforcrosscompiling.

$ export ARCH=arm
$ CROSS_COMPILE=arm-eabi-

3.Pullthekernelconfigurationfromthedeviceandthenbuildthesource.ThisstepisthesameforbuildingakernelforAndroidemulator.

$ adb pull /proc/config.gz
$ gunzip config.gz
$ mv config .config
$ make

The arm target can be found under ..kernel/arch/arm/boot.

$ ls arch/arm/boot
bootp  compressed  Image  install.sh  Makefile  zImage

The newly built kernel is "zImage".4. Change to root of the Android platform tree and build the new Android with the new kernel.

$ rm -rf out
$ make -j4 TARGET_PREBUILT_KERNEL=$HOME/myandroid/kernel/arch/arm/boot/zImage

The TARGET_PREBUILT_KERNEL will instruct the Android build system to use our custom-built kernel.

FlashAndroidImagetotheDeviceWarning!!Flashingimageswilleraseallyouruserdataonthephone!

Warning!!AttemptingthisatyourownRisk!!Yourphonewillbebricked!!

Warning!!Alwayshavefactoryimageshandysoyoucanrecoverincaseofbrickedphones!

An unlocked bootloader allows flashing custom images to an Anroid Phone. Android Dev Phone 1 and 2 ship with unlocked bootloaders. But the bootloader on Nexus One needs to be unlocked first.Both adb and fastboot can write files to the device. I use fastboot for flashing images:

UNLOCK THE BOOTLOADER IN NEXUS ONEfrom the (#References):

# Reboot phone into fastboot: Power off device and hold down trackball while powering back on. (The fastboot screen is the one with the Androids on skateboards)
   # Open a command prompt and navigate to your Android SDK tools folder.
   # Type ‘fastboot devices‘ to make sure your phone is recognized.
   # Type ‘fastboot oem unlock‘ to unlock the bootloader.
   # Use volume keys to navigate to yes and press the power button to confirm.

FLASHANDROIDIMAGESTONEXUSONEWenowflashandroidimagesthatwejustbuilttothedevice.

$ sudo $HOME/myandroid/platform/out/host/linux-x86/bin/fastboot -p passion -w flashall
[sudo] password for userone: 

< waiting for device >
--------------------------------------------
Bootloader Version...: 0.33.0012
Baseband Version.....: 4.06.00.12_7
Serial Number........: HTXXXXXXXXX
--------------------------------------------
                  checking mid... OKAY [  0.003s]
              checking product... OKAY [  0.009s]
   checking version-bootloader... OKAY [  0.002s]
       checking version-microp... OKAY [  0.004s]
     checking version-baseband... OKAY [  0.012s]
      sending 'boot' (2336 KB)... OKAY [  0.366s]
                writing 'boot'... OKAY [  0.917s]
  sending 'recovery' (2562 KB)... OKAY [  0.405s]
            writing 'recovery'... OKAY [  1.048s]
   sending 'system' (75301 KB)... OKAY [ 10.943s]
              writing 'system'... OKAY [ 25.634s]
            erasing 'userdata'... FAILED (remote: not allowed)
finished. total time: 39.418s

The error about failing to erase userdata is because we selected user build (i.e. "userdebug") when building android. We can flash it manually:

$ sudo $HOME/myandroid/platform/out/host/linux-x86/bin/fastboot flash userdata $HOME/myandroid/platform/out/target/product/passion/userdata.img
     sending 'userdata' (2 KB)... OKAY [  0.022s]
            writing 'userdata'... OKAY [  4.872s]
finished. total time: 4.894s

If the phone hangs after rebooting, we can restore it back to factory images.

RESTORE NEXUS ONE TO FACTORY SETTINGS

1. Download HTC Nexus One images from HTC Dev Center. HTC currently only provides Android 2.1 images for Nexus One. You can use your Google account to get the official 2.2 OTA update after restoring the phone to factory images.

2.Unzipimagestoadirectory.

userone@userone-laptop-2:~/Downloads/nexusone$ ls
android-info.txt  NexusOne_ERE36B_TMOUS.zip  system.img
boot.img          recovery.img               userdata.img

3. Flash all images to the device using fastboot.

ThisisthemethodIusedtorestoremyNexusOnetofactorysettings.

$ sudo $HOME/myandroid/platform/out/host/linux-x86/bin/fastboot flash boot ./boot.img
$ sudo $HOME/myandroid/platform/out/host/linux-x86/bin/fastboot flash recovery ./recovery.img
$ sudo $HOME/myandroid/platform/out/host/linux-x86/bin/fastboot flash system ./system.img
$ sudo $HOME/myandroid/platform/out/host/linux-x86/bin/fastboot flash userdata ./userdata.img

I did not use "fastboot -w flashall" and "fastboot update [some].zip" because they complained about missing files.

TIPSUseadbtobootthedeviceintotherecoverymode.

$ adb reboot recovery

• Use adb to store recovery image.

$ adb push <recovery-image-package>.zip /sdcard/update.zip

• Boot into the Nexus One recovery console.

Afterselecting"recovery"fromthefastbootscreenonNexusOne,ascreenwillshowupwithalittleandroidandacautionsign.Press"VolumeUp"andthe"power"buttonatthesametimetogointotherecoveryconsole.Testkernelbootwithoutflashing.Veryusefulindeterminingifanewkernelimagecanboot.

$ sudo fastboot boot arc/arm/boot/zImage

• Pull kernel compiling option from an existing phone.

$ adb pull /proc/config.gz

ReferencesGettingAnroidSource

AndroidBuildSystem

BuildingAOSPfortheNexusOne

CompileAndroidkernelfromthesource

FedoraARM/HowToQemu

KernelHackers'Guidetogit

HTCAndroidDevPhone1

Video:HowtoUnlockandRootaNexusOne

HTCKernelSourceandBinaries

MotorolaKernelSource

Howto:RootingyourNexusOne-adefinitiveguidetowhat’sinvolved

AndroidFastboot

MSM/QSDAndroidEnablementProject

AndroidBootProcessfromPower-on

HowtoBuildtheLINUXKERNELfortheANDROIDEMULATOR(Eclairversion)

DownloadandBuildtheGoogleAndroid

AnroidPortingonRealTarget

OpenBinder

Technoteandroid-2.6.31-001:Howtoregeneratebionic/libc/common/kernelheadersforlinuxkernelv2.6.31

Howtodumpbootmessagewithoutadb