The port to for this two targets has been entirely developped by Ilia Sergachev (alias Il or xzcc). His source
can be found at https://bitbucket.org/isergachev/rockbox . The few necesary modifications for the DX90 port
was done by headwhacker form head-fi.org. Unfortunately i could not try out the final state of the DX90 port.
The port is hosted on android (without java) as standalone app. The official Firmware is required to run this port.
Ilia did modify the source files for the "android" target in the rockbox source to make the DX port work. The work I did
was to separate the code for DX50 (&DX90) from the android target.
On this Target Ilia used source from tinyalsa from AOSP. I did not touch that part of the code because I do not understand it.
What else I changed from Ilias sources besides the separation from the target "android":
* removed a dirty hack to keep backlight off
* changed value battery meter to voltage battery meter
* made all plugins compile (named target as "standalone") and added keymaps
* i added the graphics for the manual but did not do anything else for the manual yet
* minor optimizations

known bugs:
* timers are slowed donw when playback is active (tinyalsa related?)
* some minor bugs

Things to do:
* The main prolem will be how to install the app correctly. A guy called DOC2008 added a CWM (by androtab.info) to the
  official firmware and Ilia made a CWM installation script and a dualboot selector (rbutils/ibassoboot, build with
  ndk-build). We will have to find a way to install rockbox in a proper way without breaking any copyrights.
  Maybe ADB is an option but it is not enable with OF by default. Patching the OF is probably the way to go.
* All the wiki and manual

to build:
needed: android ndk installed, android sdk installed with additional build-tools 19.1.0 installed

./tools/configure
select iBasso DX50 or iBasso DX90
make -j apk

the content of rockbox.zip/.rockbox needs to be copied to /system/rockbox/app_rockbox/rockbox/ (rockbox app not needed)
the content of libs/armeabi to /system/rockbox/lib/ (rockbox app needed)

The boot selector is needed as /system/bin/MangoPlayer and the iBasso app as /system/bin/MangoPlayer_original. There
is also the "vold" file. The one from OF does not work with DX50 rockbox (DX90 works!?), the one from Ilia is necessary.

Until we have found a proper way to install it, it can only be installed following the instructions of Ilia on his
bitbucket page, using the CWM-OF and his installation script package.

Change-Id: Ic4faaf84824c162aabcc08e492cee6e0068719d0
Reviewed-on: http://gerrit.rockbox.org/941
Tested: Chiwen Chang <rock1104.tw@yahoo.com.tw>
Reviewed-by: Michael Giacomelli <giac2000@hotmail.com>

A GNU extension that returns dst + size instead of dst. It's a nice
shortcut when copying strings with a known size or back-to-back blocks
and you have to do it often.

May of course be called directly or alternately through
__builtin_mempcpy in some compiler versions.

For ASM on native targets, it is implemented as an alternate entrypoint
to memcpy which adds minimal code and overhead.

Change-Id: I4cbb3483f6df3c1007247fe0a95fd7078737462b

Change-Id: I2c42f0e422130bcdaf1aaf92c7b56776752f4f64

With LCD driver all calculation will be performed on RGB888 and the hardware/OS
can display from our 24bit framebuffer.

It is not yet as performance optimized as the existing drivers but should be
good enough.The vast number of small changes is due to the fact that
fb_data can be a struct type now, while most of the code expected a scalar type.

lcd-as-memframe ASM code does not work with 24bit currently so the with 24bit
it enforces the generic C code.

All plugins are ported over. Except for rockpaint. It uses so much memory that
it wouldnt fit into the 512k plugin buffer anymore (patches welcome).

Change-Id: Ibb1964545028ce0d8ff9833ccc3ab66be3ee0754

This is the basic port to the new target Samsung
YP-R1, which runs on a similar platform as YP-R0.
Port is usable, although there are still
some optimizations that have to be done.

Change-Id: If83a8e386369e413581753780c159026d9e41f04

Change-Id: I5e7bdc8be7de50ef604c16078857fff1b84650dc

Change-Id: I20c3af0368202493d54fb776530300a39d47873a

using the new automatic-asm-picking infrastructure.

Example: for a file asm/foo.c, make will look for asm/arm/foo.[cS] and
compile it if found. If not found it'll fall back to asm/foo.c.

Also introduce new ARCH make variable. This is automatically detected by
configure. It is distinct from CPU since CPU defines the dir used for
the target tree (i.e. firmware/target/X, so it can be "hosted").
ARCH really has the target isa and can be x86 for sims/raaa too.

Change-Id: I18e5d2b7b7bbc2ad2be551a74a0fcae5ffbcbf8b