I would like to understand how an application like AlsaMixer or MixGet, mixer widget with alsa is working.
Specially, I would like to develop an application which makes use of the "/etc/asound.conf" which would be available with ALSA.
Has anyone more knowledge on this? How can I "build" ALSA for every Android-device?
I personally have tested those applications on my own Samsung Galaxy Nexus which natively uses "tinyalsa" and on an "HTC Desire" which uses something with "/dev/msm_audio_out" (don't know what this is exactly).
It seems that those apps require root, ok no problem, but they work without larger modifications and on a large range of devices).
Thanks in advance for your help, I've read hundreds over hundreds of docs and found no real informations.
If an Android device
actually uses ALSA drivers; and
is rooted (so that your app can access the device files),
then you could the NDK to access the ALSA libraries.
In that case, ALSA works just like on any other machine.
Related
So I have this app that only works on ARM based Android devices and not x86 based ones. Sorry I'm not too tech savvy so I might sound like I'm absolutely dumb... Anyways any suggestions? And for reference, I don't have the source code for the apk file but I know the devs so yeah... Help?
Today I found out, that I could write a libaudio.so and put it in my Android's folder /system/lib/ for custom audio-handling.
My device, a Galaxy Nexus with Android 4.2 is using tinyAlsa and has a libtinyalsa.so.
So I think I could use this project (from the father of tinyAlsa) to build a custom libaudio.so: https://github.com/broonie/tinyhardware
But: Does anyone know, if the tinyAlsa is a samsung or omap special thing, or has any newer android-version that type of audio-handling? So, would my custom libaudio.so be portable on other phones?
If not, does anyone know where I can find a libaudio.so which works with default ALSA?
I know that "AlsaMixer" from Android-market uses it but I will compile it on my own.
With kind regards & thanks in advance.
Android devices do not always use tinyalsa and there's no requirement or recommendation for them to do so. However, all Nexus devices use tinyalsa and there are no plans to change this.
from the tinyalsa author
I am interested in building Android for Source for a Galaxy S3 (but just knowing how to do it in general will be quite helpful)
I know how to do it for all the nexus devices in general, but I was wondering how to do it for some of the other phones. I know that it is possible because CyanogenMod and other modders do it. Usually when they announce them they include the source for the kernel.
How do you put the pieces together? Getting the android source code and the custom kernel together in something that can be flashed.
Generally it is not trivial. You need some binary files for hardware support (camera, WiFi, NFC, etc) and you need to figure out which those are and how to pull them from the device. The kernel is GPL licensed, so the the manufacturer will release their version/patches at some point, but you might have to wait. Then you have to create device build files to put all those together in an image for the particular device. Your best bet is to get CyanogenMod source and see how it is done in practice.
I own a Samsung Galaxy 3 and want to port kernels available for other Android Devices. I have all building environment ready. I have C knowledge also. What exactly I dont understand is how and what all things porting involves, which codes should be modified in what way?
If someone could help me. It would be great.
Thanks in advance.
Ok I got it. But the real problem is I dont understand one thing.
What needs to be changed in the source code so that to make it compatible in other device? Can someone explain me that?
Idolon gives a good suggestion. In theory what is written there is true. In practice, it's a little more involving. I've been porting Android Kernel for months now. My goal was to have a custom S5PV210 processor module on my custom board with my custom I/O. I have the source code for Samsung's galaxy tab and several Samsung's android smartphone as well as a few versions (Froyo, Gingerbread) for the Samsung's Evaluation board (SMDKV210 for S5PV210 CPU). FYI, S5PC110 is a close derivative. Here is what I found out.
Eventhough all the device drivers are supposed to be built in a very modular way and independent from each other and you should be able to replace them with similar devices, the way Samsung did it is not exactly that. To give you one example is about power management. In many low level drivers dealing with hardware devices, it calls some specific routine for other hardware devices like power management chip. So, When you change the choice of drivers in the "make xconfig" or "make menuconfig" it will remove the source code of what you don't want and add the one you want but, there are still other modules that are calling the low level function you removed. When building, you will get tons of unresolved external because you removed a power management chip that your hardware doesn't have but is used in the source you started with. I looked through several Samsung's device source code and they have branched very early on. They have been adapted by different teams and it would be a major amount of work to go from one device to the other from one source kit.
Here is how I succeeded: I bought an S5PV210 evaluation board with an already ported Android Kernel (Gingerbread). All the power management and inter dependant issues where already cleaned-up. Then, form a working kit, I could change the device I needed (the one you can't buy without a 100K unit/yr commitment) without getting stuck with the interdependancy. Then I could even change LCD resolution (from 800x480 to 1024x768), touchscreen, Cell modem etc etc. The whole thing takes about a month worth of work with only one guy (me).
Starting with a Galaxytab or other commercial device made me waste months of headakes with no useful results but the thing I've learned.
There is one requirement to succeed on my approach. You have to know the hardware you are working on. As an example, you need to know what touch screen your hardware has (chipset) to select the driver and were is it connected to hook it up to the right device (USB, Serial etc). That the same thing for all other devices (power managemnt chip, keypad, backlight, LCD etc etc)
Hope that is useful to give you an idea of the work involved and how you can do it.
You should take a look at the cached copy of Android Platform Developer's Guide and at android-porting google group.
There is also an old but useful article about porting Android to Nokia N810, which will give you some hints about Android Linux kernel porting.
I am also into android porting stuff for quite some time I suggest the following route :
Read
You need to have basic knowledge of android porting and AOSP source code, directory stucture hierarchy.
I suggest you to start reading https://books.google.co.in/books/about/Embedded_Android.html?id=plHsngEACAAJ&hl=en
and also refer https://source.android.com/devices/index.html as good guys pointed out you can also google android porting related groups and become a member there, if you are stuck on a issue there are chances similar issue might have been faced by someone else previously.
Observe
AOSP code :
Parallely you need to dive in to the android source e.g from links like https://android.googlesource.com/ observe which components are placed where in the source code, what are the updates from previous android release (like ART replaced dalvik in LL), at top level there would be generic code, code specific to your hardware called HAL in hardware/ and device/ folder.
Kernel code :
In the kernel also you need to observe the directory structure and know which things lie where like SoC specific code will be in arch/ directory defconfigs (used for selecting kernel configuration) will be arch//configs/ directory.
Also there are good books available for linux kernel, you can google them and start reading them also.
While porting kernel you need to take care of following
1.If in the new kernel there is already support of SoC which is used in hardware to be ported then you need to add only device specific changes like suppose you want to port new kernel version to samsung galaxy s3, you can take a reference android kernel having exynos support and then you need to make changes only for adding support for samsung galaxy s3.
For that you need to have reference of some old kernel having support of s3, from there you can study patches which have been added to add support for s3 and port those patches to newer kernel.
Experiment
First you can only port the bare minimum changes required to up the platform, compile and flash it on your platform, then observe the output, if everything looks fine than go on for next changes otherwise try to solve the issue.
Thanks,
Devarsh
I have a Symbian based phone with a ARM Cortex-A8 processor (SonyEricsson Vivaz) and was thinking on how hard would it be to try and port the Android OS for it. Obviously Android runs on a myriad of devices with different hardware so I imagine it shouldn't be too hard to adapt it to SE hardware. Could some one give me a clue where to start or if this is even undertakable...
How much information do you have about the hardware in the phone ? Are you starting completely from scratch ?
Porting Android is not simple task. First thing is to have Linux running (preferably 2.6.32 for more compatibility with the latest releases of AOSP.
If you can find a kernel that can run on your phone, that's one big step. After that, you want make sure that the peripherals you want to use also have the right drivers : touch interface, LCD display, SD card, audio, video. The ones that are probably most difficult will be wifi, radio (GSM) and power management module.
If you get that far, you don't have that much to go anymore, a few more changes in the kernel needed for Android, be able to compile Android correctly file system, hook up a few things like buttons and correctly interface with the drivers mentioned above...
But overall, definitely not an easy task (IMHO).