[INCOMPLETE HOW TO] Reconstruct Mi 4c kernel source

ketut.kumajaya · Mar 20, 2016

I'm writing this incomplete instruction for my friend @emfox based on the instruction I used to reconstruct Redmi 2 kernel source http://forum.xda-developers.com/and.../how-to-convert-qualcomms-dtb-to-dts-t3221223 Unfortunately I couldn't finish this instruction without Mi 4c device. This is just a quick look, short information, to check the possibility to reconstruct an open source kernel based on CAF project. It's will be hard but not impossible.

1. Clone MSM8992 vanilla kernel source, LA.BF64.1.2.2-02940-8x92.0 release for Marshmallow 6.0.1 (release LA.BF64.1.2.1.c1-05410-8x92.0 branch LA.BF64.1.2.1.c1_rb1.38 for Lollipop 5.1.1) https://www.codeaurora.org/cgit/quic/la/kernel/msm-3.10/?h=LA.BF64.1.2.2_rb4.22

Code:

git clone git://codeaurora.org/quic/la/kernel/msm-3.10 -b LA.BF64.1.2.2_rb4.22

2. Stock 4c kernel was compiled without CONFIG_IKCONFIG, vanilla kernel config libra_defconfig attached
3. Attached 3 dts file from stock kernel, msm8992-mtp-0xc.dts seem compatible to emfox device (qcom,board-id = <0xc 0x0>; )
4. Attached a vanilla dts file for MSM8992 MTP msm8992-mtp.dts as a result of LA.BF64.1.2.2_rb4.22 built

You can compare msm8992-mtp-0xc.dts to msm8992-mtp.dts using a diff tool (i.e. Kompare app) and start creating device tree source for Mi 4c: msm8992-mtp-libra.dts, msm8992-mtp-libra.dtsi, batterydata-itech-3020mah.dtsi, dsi-panel-sharp-rsp61322-1080p-video.dtsi, dsi-panel-auo-nt35596-1080p-video.dtsi, dsi-panel-lgd-nt35596-1080p-video.dtsi, dsi-panel-sharp-nt35595-1080p-video.dtsi, dsi-panel-jdi-nt35595-1080p-video.dtsi, msm8992-camera-sensor-mtp-libra.dtsi, etc. You can use https://github.com/kumajaya/android...mmit/3de4f3564a82f44049a8664d4383c6d3ed43cb47 as a reference. Mi 4c based on same board platform as LG G4 or Nexus 5X. Good luck!

How to build kernel outside Android source tree:

I assume your home directory is /home/user, kernel source inside /home/user/android/libra/kernel, Android source tree inside /home/user/android/system-13.0
1. Create an environtment text file, save it as /home/user/android/build-arm64.env (change CROSS_COMPILE to point to your toolchain):

Code:

export CROSS_COMPILE='/home/user/android/system-13.0/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin/aarch64-linux-android-'
export LDFLAGS=''
export CFLAGS=''
export SUBARCH=arm64
export ARCH=arm64

2. Import environtment file above, create a build directory outside the kernel source tree (to keep the kernel source clean):

Code:

$ cd /home/user/android/libra/kernel
$ source /home/user/android/build-arm64.env
$ mkdir -p /home/user/android/libra/kernel-out
$ make O=/home/user/android/libra/kernel-out mrproper

3. Import the kernel config file, change the kernel configuration (if needed) and start the building process:

Code:

$ make O=/home/user/android/libra/kernel-out libra_defconfig
$ make O=/home/user/android/libra/kernel-out menuconfig
$ make O=/home/user/android/libra/kernel-out

4. Copy the resulting kernel and modules (if available) to a binary directory:

Code:

$ mkdir -p /home/user/android/libra/kernel-bin
$ mkdir -p /home/user/android/libra/kernel-bin/modules
$ cp /home/user/android/libra/kernel-out/arch/arm64/boot/Image /home/user/android/libra/kernel-bin/
$ find /home/user/android/libra/kernel-out/ -type f -name *.ko -exec cp {} /home/user/android/libra/kernel-bin/modules/ \;

Creating a boot image:
Remember, this is incomplete guide

Autines · Jan 30, 2016

Roger that! I thought you have bought xiaomi 4c several days ago.

emfox · Jan 30, 2016 at 2:55 PM

You're so kind to provide this tutorial. Since I know nearly nothing about kernel development, I'll start learning it step by step.

kevinnol · Jan 30, 2016

Thanks for the instruction.
Also @ekkilm / Teamsuperluminal might be able to help :fingers-crossed:

ketut.kumajaya · Jan 31, 2016 at 1:08 AM

Autines said:
Roger that! I thought you have bought xiaomi 4c several days ago.

No, too expensive and my main device still in very good condition :laugh:

emfox said:
You're so kind to provide this tutorial. Since I know nearly nothing about kernel development, I'll start learning it step by step.

No problem, you also helped me a lot.

kevinnol said:
Thanks for the instruction.
Also @ekkilm / Teamsuperluminal might be able to help :fingers-crossed:

You're welcome.

emfox · Jan 31, 2016 at 12:27 PM

OK, I've gone through the buiding kernel outside android tree steps, and now am trying to build MSM8992 vanilla kernel source from inside cm13 source directory.
command is 'source build/envsetup.sh &&breakfast libra && mka bootimage', but always got a command not found error, don't know what is missing...

Code:

<manifest>
<remote name="ghub" fetch="git://github.com/"/>
 <project name="xiaomi-dev/android_device_xiaomi_libra.git" path="device/xiaomi/libra" remote="ghub" revision="cm-13.0"/>
 <project name="AndropaX/proprietary_vendor_xiaomi_libra" path="vendor/xiaomi/libra" remote="ghub" revision="master"/>
</manifest>

and put kernel source to kernel/xiaomi/libra.

The error is

Code:

host C++: libc++_static <= external/libcxx/src/strstream.cpp
host C++: libc++_static <= external/libcxx/src/system_error.cpp
host C++: libc++_static <= external/libcxx/src/thread.cpp
host C++: libc++_static <= external/libcxx/src/typeinfo.cpp
host C++: libc++_static <= external/libcxx/src/utility.cpp
host C++: libc++_static <= external/libcxx/src/valarray.cpp
host StaticLib: libc++abi (/home/emfox/android/system-13.0/out/host/linux-x86/obj/STATIC_LIBRARIES/libc++abi_intermediates/libc++abi.a)
host StaticLib: libmincrypt (/home/emfox/android/system-13.0/out/host/linux-x86/obj/STATIC_LIBRARIES/libmincrypt_intermediates/libmincrypt.a)
host C: acp <= build/tools/acp/acp.c
host StaticLib: libhost (/home/emfox/android/system-13.0/out/host/linux-x86/obj/STATIC_LIBRARIES/libhost_intermediates/libhost.a)
Building kernel...
/bin/bash: line 1: @: command not found
Export includes file: system/core/libcutils/Android.mk -- /home/emfox/android/system-13.0/out/host/linux-x86/obj/SHARED_LIBRARIES/libcutils_intermediates/export_includes
make[1]: Entering directory '/home/emfox/android/system-13.0/kernel'
make[1]: *** No rule to make target 'libra_defconfig'.  Stop.
make[1]: Leaving directory '/home/emfox/android/system-13.0/kernel'
make[1]: Entering directory '/home/emfox/android/system-13.0/kernel'
make[1]: *** No rule to make target 'headers_install'.  Stop.
make[1]: Leaving directory '/home/emfox/android/system-13.0/kernel'
kernel/xiaomi/libra/AndroidKernel.mk:110: recipe for target '/home/emfox/android/system-13.0/out/target/product/libra/obj/KERNEL_OBJ/.build_stamp' failed
make: *** [/home/emfox/android/system-13.0/out/target/product/libra/obj/KERNEL_OBJ/.build_stamp] Error 2
make: *** Waiting for unfinished jobs....
make: Leaving directory '/home/emfox/android/system-13.0'

#### make failed to build some targets (01:41 (mm:ss)) ####

alterbang · Jan 31, 2016 at 2:00 PM

Hi @emfox, i would gladly help you since i just finished cm12.1 build with device tree (i made a thread, with prebuilt kernel of course) and I'd like to start with cm13.
If you open source kernel has compiled correctly, can you do a "kernel_xiaomi_libra" github repository?

emfox · Jan 31, 2016 at 2:06 PM

alterbang said:
Hi @emfox, i would gladly help you since i just finished cm12.1 build with device tree (i made a thread, with prebuilt kernel of course) and I'd like to start with cm13.
If you open source kernel has compiled correctly, can you do a "kernel_xiaomi_libra" github repository?

no, not really. I haven't finished the source.
I have little kernel hacking knowledge, so I'd like to set up and working environment first, then I'll go to deal these *dts files.

alterbang · Jan 31, 2016 at 2:14 PM

Ok, sorry then. I thought "'I've gone through the buiding kernel outside android tree steps," meant you had already finished

Maybe when I'll have some free time in the next days i will give the entire process a try!

emfox · Jan 31, 2016 at 2:24 PM

alterbang said:
Ok, sorry then. I thought "'I've gone through the buiding kernel outside android tree steps," meant you had already finished
Maybe when I'll have some free time in the next days i will give the entire process a try!

oh, that would be great. I'm a developer but just on web and application domain, and have no much time to dig into kernel deeply. But I am learning

ketut.kumajaya · Jan 31, 2016 at 6:24 PM

@emfox Don't forget copy libra_defconfig to arch/arm64/configs/

emfox · Jan 31, 2016 at 11:08 PM

ketut.kumajaya said:
@emfox Don't forget copy libra_defconfig to arch/arm64/configs/

yes i have copied, or the error msg will be 'cannot found kernel configuration ...blabla'

ketut.kumajaya · Feb 1, 2016 at 5:53 AM

emfox said:
yes i have copied, or the error msg will be 'cannot found kernel configuration ...blabla'

Please recheck your device board config, you can use LG G4 config as a reference https://github.com/CyanogenMod/andr...mon/blob/cm-13.0/BoardConfigCommon.mk#L49-L61

erostiff · Feb 9, 2016 at 7:38 PM

don't understand a thing from the coding but from what i have learned, kernel source would be awesome to develop more for the 4c. keep up the good work!

kevinnol · Feb 9, 2016 at 8:09 PM

Yea would be really awesome, too bad xiaomi doesn't release it themself

Well there are a lot of crazy guys here on xda so there's still hope

ketut.kumajaya · Feb 18, 2016 at 1:27 PM

Thinking to help @emfox to create a such template for 4c but no much free time here, just a short free time between my workload and no much interest without the device

emfox · Feb 18, 2016 at 5:35 PM

ketut.kumajaya said:
Thinking to help @emfox to create a such template for 4c but no much free time here, just a short free time between my workload and no much interest without the device

yes, a working building directory structure will help me start the porting.
but no need hurry, we now have cm from www.teamsuperluminal.org. although it's close-sourced and use prebuilt kernel, still much better than miui.

michfood · Feb 29, 2016 at 3:57 AM

Hi, anyone can give some more info how to build AOSP from nexus 5X?

michfood · Mar 1, 2016 at 5:06 PM

am i alone like Taylor?

hrkfdn · Mar 2, 2016 at 7:08 PM

Looks like the kernel source will be released soon: http://en.miui.com/thread-235127-1-1.html

[INCOMPLETE HOW TO] Reconstruct Mi 4c kernel source

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