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[GUIDE]Development for GalaxyTab 7.7 and Plus. How hard could it be?

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Smile [GUIDE]Development for GalaxyTab 7.7 and Plus. How hard could it be?

Planning this for sometimes. So much work ahead. Just studying the new code cause me a lot of time. I think I have to rush it out so that someone may share my burden. Don't have much time to polish it. I'm trying to provide all commands, files and links. Please correct me if something is wrong or missing. Hoping this could be a stepping stone for those interested. If you like challenge, it'll be fun!

1. Introduction
If you have watched "Top Gear", you would have heard Jeremy Clarkson said "How hard could it be?". Why is it so hard to build a rom for our tab?
When I first play with rom building, it was quite straightforward. I recuilt my retired PC (Celeron 1.2G with 3G RAM, 40G HD) and follow the guild for building PA. Installing Ubuntu 12.04 and then the necessary packages. Everything is ready in a few hours. It was really challenging your patience to repo sync the source. After a few retries, I finally completed the download in two days! After two hours, my harddisk is full! Then I collected another retired 80G HD from a friend. Re-install everything and build again. Building requried 7 hours on my antique PC. With only a few minor errors to correct, my first rom pa2.55 was out. So how hard could it be? It was our predecessors ( @ohanar, @locerra, etc.) who had already done lots of hardwork on device trees and kernel! If Samsung has really released the hardware related sources, there will not be so much troubles for us. At the time Android 4.2 launch, we have a new problem. Our tab's CSR chip doesn't support Bluedroid. See the Nexus family, everything is ready. Rom building will never be so pain in the ass as us.

1.1 What's wrong with our hardware
GT-7.7 and Plus use the exynos4 smdk4210 board with Mali-400 GPU. Quite a number of devices have similar hardware. The main problem we have would be:
1.1.1 CSR bluetooth chip.
CSR chip doesn't support bluedroid which become standard after Android 4.2. Bluez.org has provide a solution for 4.2 early this year but porting to 4.3 and 4.4 may take some time.Working on it now. Anyone has experience on bluetooth are welcome to help.. Bluez working now. See my Thread How to port Bluez to Android 4.4. Cheers!
1.1.2 Athero wifi chip.
Samusng's wifi driver has issues on 5G support and SOD. I'm using the modified kernel driver from Samsung's 4.1.2 source. Athero provide drivers for 3.1 to 3.10 linux kernels but they have no wakelock support. I also wrote a drive base on Athero's source and add wakelock support but have no time to polish it now. Athero's chip doesn't have firmware for AP as Boardcom. Which is also the way Android platform providing wifi tethering in framework. To support wifi tethering we have to change the framework and the driver. Anyone has experience in linux HostAP are welcome to help. Wifi tethering is ok now! Tutorial will be in Post#2 soon.
1.1.3 modem chip (xm6260).
RIL stand for (radio interface library). Most of the phone manufacturer would provide their own vendor lib. The only working blob now is Samsung's ICS propietry libsec-ril.so which is obselete now. The one from stock 4.1.2 not working but no time to trace. It also don't seems to have much difference. This library handle the AT commands issuing to the (baseband to) modem chip. xm6260 has a complete set of command manual. It should not be too hard to rewrite if we can hack the ports. However it is not worth to splend too much time on this. Those has experience in AT commands are welcome to help.
RIL details: http://www.kandroid.org/online-pdk/guide/telephony.html

1.2 Where to get the source?
1.2.1 Samsung's source for our tab
The best source would be from Samsung http://opensource.samsung.com/. Sadly, the source from Samsung only cover the kernel. Our tab only have source up to 4.1.2 and kernel source 3.0.31 from Samsung.
1.2.2 Samsung's source for other devices
Luckly, we have similar architecture to some newer Samsung models. Their source is our major source now. eg. We can use the Mali driver from Note8 and/or i9300.
1.2.3 Manufacturere's web site.
The other source would be from the chip manufacturer. eg. Athero has source for linux.

1.3 What is going on at boot?
1.3.1 Power ON
a) When power button is long pressed (should be released after the logo shows otherwise it will reboot again every 6 seconds). The manufacturer's booloader would show the vendor's logo. At that moment, bootloader would sense if there are key being pressed. Standard Android will go to boot menu when pwr + vol- is pressed. Samsung would go to download mode (something like fastboot) and accept pwr + vol+ to start recovery mode. If no other key is pressed, it would be a normal boot.
b) When USB is plug in (PC usb port or charger) at power off, the tab will be turn on silently. It is in the LPM (low power mode). According to lpm.rc (executed by Init, will be explained in 1.3.3), CPU will be set to POWERSAVING and the program charger is running. It should only handle simple tasks like Detecting the pwr button to show the charging images. If the pwr is long press when showing the charging image, it will reboot as in a).
1.3.2 Boot image
For our tab, there are two parts for a boot.img or a recovery.img. kernel binary and initramfs. As the name imply, Init-Ram-FS is the initial file system loaded into ram when the devices boot. Kernel binary provide the hardware drivers libraies which communicate with the hardware and baseband. At normal boot or recovery mode, the image (in /boot or /recovery partition) will be decompressed and loaded to memory. Initramfs will be loaded in root(/). It would consume a few hundreds MB of RAM and that's why our free ram is only 7xxM.
In LPM, it would depends on the last boot state. If it was powered off from recovery, recovery.img will be loaded and handle the LPM. If it was powered off from platform, boot.img will be loaded and handle LPM. That's why It might show different charging images if the charging images for reovery.img and boot.img are different.
Stock cook roms can unpack and modified the initramfs from the existing zImaage. It is created in system/core if we build it from source. Here is a tool which can unpack/repack our boot.img or recovery.img.
1.3.3 Init
There is the Init program in every initramfs. This is the first program to run according to the sequence in the init.rc (or lpm.rc when in LPM). Partitions will be mounted and symlinks, default values and permissions are assigned, services will be started, etc. The source of Init is in system/core. The last thing Init do would be the continuous eventloop to process events.

2. Getting Start
To start building, we need the building environment. Many tutorials have alreay covered the details so I just list my suggestions. The guide from Google is a bit outdated but really helpful. http://source.android.com/source/building.html
Basic knowledge of linux is required. All commands are run in a terminal.

2.1 Hardware
A decent PC with as much ram as possible. Thanks for the donations, I can upgrade to a better i5 notebook with 4G ram and a 500G partition only for building. It would take 3+hrs. for a clean build. RAM and Harddisk speed are essential. A desktop PC with same configuration will be faster since notebook harddisk is slow. I plan to add more RAM when the price drop (seems to be a long wait )
RAM: 4G or above is recommended.
Harddisk space: 30G+ for system, 60G+ per rom, size of ccache (50G-100G), Roughly, a partition with at least 120G for one rom. Bigger is better.
A decent internet connection is essential. It will take days to sync the source if you only have bandwidth of 2M or less .

2.2 OS
64bit Ubuntu Desktop 12.04 or above. Recommend 13.04 or above.I'm using the latest 13.10.

2.3 Install the required packages
These packages are required during building and packing. (eg. gzip is required to compress the kernel binary)
type command: (have a beer or coffee. It will take a while)
Code:
sudo apt-get install git-core gnupg flex bison gperf build-essential zip curl zlib1g-dev zlib1g-dev:i386 \
 libc6-dev lib32ncurses5-dev ia32-libs x11proto-core-dev libx11-dev:i386 libreadline6-dev:i386 lib32z-dev \
 libgl1-mesa-glx:i386 libgl1-mesa-dev g++-multilib mingw32 tofrodos python-markdown libxml2-utils xsltproc \
 readline-common libreadline6-dev libreadline6 bzip2 libbz2-dev libbz2-1.0 libncurses5-dev lib32readline5 \
 lib32readline-gplv2-dev lib32readline6 libreadline-dev libreadline6-dev:i386 libreadline6:i386 pngcrush \
 libghc-bzlib-dev lib32bz2-dev libsdl1.2-dev libesd0-dev squashfs-tools schedtool libwxgtk2.8-dev python

sudo ln -s /usr/lib/i386-linux-gnu/mesa/libGL.so.1 /usr/lib/i386-linux-gnu/libGL.so
2.4 Insatll android-sdk
Download (for Linux 64-bit of course): http://developer.android.com/sdk/index.html
Extract the file to a directory (eg. ~/android-sdk)
Add the path to ~/.bashrc
type command:
Code:
sudo gedit ~/.bashrc
at the bottom add the path
Code:
export PATH=~/bin:~/android-sdk/tools:~/android-sdk/platform-tools:$PATH
Quit and restart terminal to commit the changes.
Verify the path and update the SDK
type command:
Code:
android
2.5 Install java6
If you have installed eclipse, openJAVA will be ready. Some say it is not suitable for android development.
I've tried both and I found no appearing difference.
To install SUN JAVA (Ubuntu 13.04 or above)
type command:
Code:
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update
sudo apt-get install oracle-java6-installer
2.6 Install repo
type command:
Code:
mkdir -p ~/bin
curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo > ~/bin/repo
chmod a+x ~/bin/repo
2.7 Add usb dev rules
Which are required for adb and fastboot, eg. 51-android.zip
type command:
Code:
sudo cp 51-android.rules /etc/udev/rules.d
sudo chmod 0644 /etc/udev/rules.d/51-android.rules
2.8 Enable ccache
type command:
Code:
sudo gedit ~/.bashrc
add lines for CCACHE
Code:
export USE_CCACHE=1
export CCACHE_DIR=~/android/.ccache
Quit and launch the terminal again to commit the changes
ccache will cache the object files of gcc for next build, it would increase the speed of subsequent builds alot.
After source is sync in 2.11 and before build, we can set the size of ccache first.
type command:
Code:
~/android/rom/prebuilts/misc/linux-x86/ccache -M<size>
2.9 Init the source
Make a new working driectory for your rom
type command: (eg. ~/android/rom)
Code:
mkdir -p ~/android/rom
Each rom has its own manifest.xml listing all the required projects.
It is usually in the project android (manifest for PA). The readme of this project would provide the command to init.
eg. CM11.0: https://github.com/CyanogenMod/android/tree/cm-11.0
type command:
Code:
repo init -u git://github.com/CyanogenMod/android.git -b cm-11.0
It will fetch the manifest.xml and put it into a hidden directory .repo in the current directory (~/android/rom/.repo)

2.10 preparing local_manifest.xml
It is not a good pratice to change to manifest.xml directly. If the ROM has change its manifest, you would require to init again. The right way is putting everything your device needed in a seperate file .repo/local_manifest/local_manifest.xml. The device trees and kernel source for GalaxyTab 7.7 and Plus : https://github.com/danielhk?tab=repositories
eg. cm11.0 for p6800
Code:
<?xml version="1.0" encoding="UTF-8"?>
<manifest>
  <project name="ohanar/android_hardware_atheros_wlan" path="hardware/atheros/wlan" remote="github" revision="cm-10.1" />
  <project name="danielhk/android_device_samsung_p6800" path="device/samsung/p6800" />
  <project name="danielhk/android_device_samsung_smdk4210-tab" path="device/samsung/smdk4210-tab" />
  <project name="danielhk/android_kernel_samsung_smdk4210" path="kernel/samsung/smdk4210" />
  <project name="danielhk/proprietary_vendor_samsung_smdk4210" path="vendor/samsung" />
</manifest>
Note: Settings will follow manifest.xml. cm-11.0's manifest has default remote="github" and revision="refs/heads/cm-11.0" so we can omit the same entries here. For other roms, see the defined names in manifest.xml and change accordingly. You can also add other devices trees here if you want to build them for the same rom.

2.11 sync and build
To fetch the source (specified in manifest.xml and local_manifest.xml) to working directory (~/android/rom)
type command:
Code:
repo sync -j32
-J specify the no. of threads to download. I have a few trials. Seems 32 works for me.
When it is done. You will find that ~/android/rom is not empty now.

You may set the ccache size now:
type command: (eg. 50G)
Code:
~/android/rom/prebuilts/misc/linux-x86/ccache -M50G
Only if you want to change size, otherwise it only requires once.

To build a rom, change to the rom directory. Usual commands: (eg. for CM roms)
Code:
cd ~/android/rom
. build/envsetup.sh
lunch cm_p6800-userdebug
mka bacon
CM need to download a prebuilt (Termianl.apk). To simplify this routines, I modified the build script from PA to cm rom-build.zip.
Copy it to the rom directory, type command:
Code:
cd ~/android/rom
./rom-build.sh p6800
After building is complete with no error, the rom will be output to ~/android/rom/out/target/product/p6800.

3. What can we do?
3.1 Kernel
Since Samsung provide the complete kernel source, working on kernel would be comparatively speaking much easier.
When we say kernel, we mean the boot.img or zImage which already include the initramfs. This image will be flash to the /kernel (/dev/block/mmcblk0p5)
Hardware and flags are defined in defconfig inside <kernel dir>/arch/arm/config. It is the Linux standard.
3.1.1 difference between stock kernel and the kernel in custom rom
The main difference between the two kernels is the location of kernel library modules. Libray modules are mainly for network and storage drivers. By building them as modules, they can be stoped and restarted in case of critical errors.
Stock kernel put it in /lib which is part of the initramfs. We need to do extra steps to manually copy them to the initramfs after the first build and rebuild again. If you want to build the stock kernel, there is a very good tutorial.
Custom rom put the kernel library modules in /system/lib. Thus boot.img need to match those modules, otherwise they will not work properly.
For custom roms, which defconfig to be used is defined in device tree.
eg. For p6800, in the file device/samsung/p6800/BoardConfig.mk. There is the line:
Code:
TARGET_KERNEL_CONFIG := cyanogenmod_p6800_defconfig
It specify which defconfig file for the kernel
I wrote a build-k.zip scirpt to simplify the building of kernel alone. Copy it to the rom working directory (~/android/rom)
eg. For p6800, type command:
Code:
./build-k p6800
New boot.img will be output to the same directory as rom if no error.
3.1.2 Add/modify O/C, U/V, GOVERNORS, hardware drivers, etc.
As mentioned in 1.2, we can copy/modified the source from i9100 and n7000 kernels. For example, Dorimanx and Slyahkernel provide many useful code for us. The source of i9300 from Samsung may also provide some drivers update (eg. Mali)
3.1.3 Default Orientation
Why the incall screen always landscape?
Many apks assume the default orientation is portrait but our tab's default orientation is landscape. It is a kernel behaviour so that recoveries (including the stock 3e recovery) are all in landscape.
To avoid this odd behaviour of apks like inCall screen, changing the default orientation in kernel is the ultimate solution.
It is already in my do list for a long time but trying to keep up with the android plaftform already occupy all my spare time...
I already have some idea how to do. Anyone interested to help on this can PM me.
3.1.4 Update the kernel source
The existing kernel is base on Linux 3.0.x. It is outdated but I don;'t thinks Samsung would bother to update it. I had tried starting with the 3.4 source from Google but don't have enough time to carry on. I have filled some drivers already. Will take another shot later if I have time...
Anyone have experience in Linux kernel are welcome to help. No more guides are there, this would be a great challenge but fun!

3.2 device tree
Every device requires a device tree which:
a) Specify the hardware
b) define some overrided library. (eg. sensor, camera)
c) provide the extra files to be put in the initramfs. (init.<device>.rc, fstab.<device>, etc.)
If there are a few models variants, common parts would be put in a seperate common device tree (eg. smdk4210-tab for our tab). In this way, changing can be made once for all variants.
Most of the work on porting for a specific ROM would be on the device tree. Same as the kernel, we can get some update by modifying from other devices. CM's device tree for i9100, n7000 and i9300, etc. With a good device tree, we can port to any ROM.

3.3 Bluetooth support after 4.2.
In 4.2.2, I changed the source of framework, system_core, phone apk and device tree to work with bluez. It was a huge job! Hundreds of lines had been changed. Many files are replaced. It was quite clumsy but was the only way then. This way may not work for 4.3 onward.
Here are the details of both stack:
Bluedriod : http://source.android.com/devices/bluetooth.html
Bluez : http://www.kandroid.org/online-pdk/guide/bluetooth.html
3.3.1 We may modify the bluedroid to support our chip.
3.3.2 Working on the bluez support. I'm trying now.
  Bluez5 is OK now. See my thread: How to port Bluez to Android 4.4

3.4 Recoveries
With the device tree and kernel, we can build the recovery from source. CWM would be a side product of CM roms and TWRP has a tutorial.
The same build-k.zip script can be used to build recovery alone. In the rom working direcotry, to build recovery only
type command:
Code:
./build-k p6800 recovery
With no error, recovery.img will be at the same output directory as rom.

"I am only one, but I am one. I cannot do everything, but I can do something. And because I cannot do everything, I will not refuse to do the something that I can do. What I can do, I should do. And what I should do, by the grace of God, I will do." - Edward Everett Hale
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daniel_hk
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Tutorials:
WiFi tethering

"I am only one, but I am one. I cannot do everything, but I can do something. And because I cannot do everything, I will not refuse to do the something that I can do. What I can do, I should do. And what I should do, by the grace of God, I will do." - Edward Everett Hale
 
Vaka2
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daniel_hk, Check and commit to your tree my patches for PAC-4.2.2
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Quote:
Originally Posted by Vaka2 View Post
daniel_hk, Check and commit to your tree my patches for PAC-4.2.2
Thanks!
It nice to see someone interested in our development!

I have look into your changes briefly.
1. Some changes in media which I'll leave the user to decide. I rather keep the builds as genuie as possible.
2. Some of them are new commit of the original source which will automatically updated in a sync.
3. I forgot to upload a few minor projects to github.

One of which was android_build which will include the files like hciattach building from source. If you study the source of exteranl/bluetooth/bluez, they are there. That means it might have update later. No need to add as a blob.

Actually the best way is including them in PROJECT_PACKAGES section of the device.mk. It would have the same result without touching the original source. Less touch to the original source means fewer conflict later. I was caught up and did't have time to tidy up everything so I leave it there. Also, files from bluetooth should be put in the smdk4210-tab device tree. All model share the same source.

vendor_pac should be upload to official PAC's git. They already gave me an account but they use Google+ which I have trouble to login here. I was working on a job and I hadn't follow up. Now I'm working on 4.4 which PAC haven't release yet. So I put aside first.

You probably didn't have to waste you time if you PM me first.

Everytime I upload to github is a challenge, it always break before complete. I have to monitor it from time to time. Annoying! So I can only upload once a while when everything is ready...

To be honest, I really don't have time to keep up with the old source. The new ports already occupy all my spare times. With limited resource, I can only focus on major issues. Bluetooth after 4.3 is my first priorty. If it can be done, means we can go much further.

If you are interested, you may pick one of the thing I mentioned in this thread to start. Wifi-tethering or the vendor ril library is needed too. You may try it in 4.2.2 first. See what you are good at and interested to. PM me or post again if you have any questions and/or suggestion.

Thanks again for your effort.

"I am only one, but I am one. I cannot do everything, but I can do something. And because I cannot do everything, I will not refuse to do the something that I can do. What I can do, I should do. And what I should do, by the grace of God, I will do." - Edward Everett Hale
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lomniom
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Quote:
Originally Posted by daniel_hk View Post
Thanks!
It nice to see someone interested in our development!

I have look into your changes briefly.
1. Some changes in media which I'll leave the user to decide. I rather keep the builds as genuie as possible.
2. Some of them are new commit of the original source which will automatically updated in a sync.
3. I forgot to upload a few minor projects to github.

One of which was android_build which will include the files like hciattach building from source. If you study the source of exteranl/bluetooth/bluez, they are there. That means it might have update later. No need to add as a blob.

Actually the best way is including them in PROJECT_PACKAGES section of the device.mk. It would have the same result without touching the original source. Less touch to the original source means fewer conflict later. I was caught up and did't have time to tidy up everything so I leave it there. Also, files from bluetooth should be put in the smdk4210-tab device tree. All model share the same source.

vendor_pac should be upload to official PAC's git. They already gave me an account but they use Google+ which I have trouble to login here. I was working on a job and I hadn't follow up. Now I'm working on 4.4 which PAC haven't release yet. So I put aside first.

You probably didn't have to waste you time if you PM me first.

Everytime I upload to github is a challenge, it always break before complete. I have to monitor it from time to time. Annoying! So I can only upload once a while when everything is ready...

To be honest, I really don't have time to keep up with the old source. The new ports already occupy all my spare times. With limited resource, I can only focus on major issues. Bluetooth after 4.3 is my first priorty. If it can be done, means we can go much further.

If you are interested, you may pick one of the thing I mentioned in this thread to start. Wifi-tethering or the vendor ril library is needed too. You may try it in 4.2.2 first. See what you are good at and interested to. PM me or post again if you have any questions and/or suggestion.

Thanks again for your effort.
Thanks to you Daniel for your immense effort on detailing all this! I'm far from a dev status like you and @UpInTheAir. But my support will always go to you developers. Both of you has done an impressive work for an outdated hardware and keep us happy with your Rom and Kernel. Again, thanks a lot.
 
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Thanks, all hail daniel_hk for this!
 
juniorhxcx
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Daniel,

I can only thank you for all the work he is having to keep our equipment (62xx, 68xx, TXX) alive and really Kitkat will give a new breath, for even in an experimental state already see how the device works smoother. A feather can not help, but I'm looking forward to seeing this in functional status.

As a suggestion, I honestly do not know the procedures, but it would be interesting to ask an official support OmniROM (ROM promising, others liked) and CM. The Galaxy SII has the same hardware, in which the use OmniROM and this magnifies the ROM. Maybe they (Team OmniROM) may offer official support or at least help in these matters!

I'm almost begging for support OmniROM, and Entropy512 (http://forum.xda-developers.com/memb...87892739940434) Kindly reply me: "Someone who is working with one of Those devices and has it working needs to submit it. "

Sorry for my english

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