Reorganization

- Separated iBasso devices from PLATFORM_ANDROID. These are now standlone
  hosted targets. Most device specific code is in the
  firmware/target/hosted/ibasso directory.
- No dependency on Android SDK, only the Android NDK is needed.
  32 bit Android NDK and Android API Level 16.
- Separate implementation for each device where feasible.

Code cleanup

- Rewrite of existing code, from simple reformat to complete reimplementation.
- New backlight interface, seperating backlight from touchscreen.
- Rewrite of device button handler, removing unneeded code and fixing memory
  leaks.
- New Debug messages interface logging to Android adb logcat (DEBUGF, panicf,
  logf).
- Rewrite of lcd device handler, removing unneeded code and fixing memory leaks.
- Rewrite of audiohw device handler/pcm interface, removing unneeded code and
  fixing memory leaks, enabling 44.1/48kHz pthreaded playback.
- Rewrite of power and powermng, proper shutdown, using batterylog results
  (see http://gerrit.rockbox.org/r/#/c/1047/).
- Rewrite of configure (Android NDK) and device specific config.
- Rewrite of the Android NDK specific Makefile.

Misc

- All plugins/games/demos activated.
- Update tinyalsa to latest from https://github.com/tinyalsa/tinyalsa.

Includes

- http://gerrit.rockbox.org/r/#/c/993/
- http://gerrit.rockbox.org/r/#/c/1010/
- http://gerrit.rockbox.org/r/#/c/1035/

Does not include http://gerrit.rockbox.org/r/#/c/1007/ due to new backlight
interface and new option for hold switch, touchscreen, physical button
interaction.

Rockbox needs the iBasso DX50/DX90 loader for startup, see
http://gerrit.rockbox.org/r/#/c/1099/

The loader expects Rockbox to be installed in /mnt/sdcard/.rockbox/. If
/mnt/sdcard/ is accessed as USB mass storage device, Rockbox will exit
gracefully and the loader will restart Rockbox on USB disconnect.

Tested on iBasso DX50.
Compiled (not tested) for iBasso DX90.
Compiled (not tested) for PLATFORM_ANDROID.

Change-Id: I5f5e22e68f5b4cf29c28e2b40b2c265f2beb7ab7

Either by mistake or because its meaning changed, usb_powered() doesn't mean
what the name suggest, so clarify its meaning by renaming it to usb_powered_only.
So use of usb_powered() are replaced by usb_inserted() when it makes more sense.

Change-Id: I112887e2d8560e84587bee5f55c826dde8c806d8
Reviewed-on: http://gerrit.rockbox.org/1097
Reviewed-by: Amaury Pouly <amaury.pouly@gmail.com>

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>

This patch redoes the filesystem code from the FAT driver up to the
clipboard code in onplay.c.

Not every aspect of this is finished therefore it is still "WIP". I
don't wish to do too much at once (haha!). What is left to do is get
dircache back in the sim and find an implementation for the dircache
indicies in the tagcache and playlist code or do something else that
has the same benefit. Leaving these out for now does not make anything
unusable. All the basics are done.

Phone app code should probably get vetted (and app path handling
just plain rewritten as environment expansions); the SDL app and
Android run well.

Main things addressed:
1) Thread safety: There is none right now in the trunk code. Most of
what currently works is luck when multiple threads are involved or
multiple descriptors to the same file are open.

2) POSIX compliance: Many of the functions behave nothing like their
counterparts on a host system. This leads to inconsistent code or very
different behavior from native to hosted. One huge offender was
rename(). Going point by point would fill a book.

3) Actual running RAM usage: Many targets will use less RAM and less
stack space (some more RAM because I upped the number of cache buffers
for large memory). There's very little memory lying fallow in rarely-used
areas (see 'Key core changes' below). Also, all targets may open the same
number of directory streams whereas before those with less than 8MB RAM
were limited to 8, not 12 implying those targets will save slightly
less.

4) Performance: The test_disk plugin shows markedly improved performance,
particularly in the area of (uncached) directory scanning, due partly to
more optimal directory reading and to a better sector cache algorithm.
Uncached times tend to be better while there is a bit of a slowdown in
dircache due to it being a bit heavier of an implementation. It's not
noticeable by a human as far as I can say.

Key core changes:
1) Files and directories share core code and data structures.

2) The filesystem code knows which descriptors refer to same file.
This ensures that changes from one stream are appropriately reflected
in every open descriptor for that file (fileobj_mgr.c).

3) File and directory cache buffers are borrowed from the main sector
cache. This means that when they are not in use by a file, they are not
wasted, but used for the cache. Most of the time, only a few of them
are needed. It also means that adding more file and directory handles
is less expensive. All one must do in ensure a large enough cache to
borrow from.

4) Relative path components are supported and the namespace is unified.
It does not support full relative paths to an implied current directory;
what is does support is use of "." and "..". Adding the former would
not be very difficult. The namespace is unified in the sense that
volumes may be specified several times along with relative parts, e.g.:
"/<0>/foo/../../<1>/bar" :<=> "/<1>/bar".

5) Stack usage is down due to sharing of data, static allocation and
less duplication of strings on the stack. This requires more
serialization than I would like but since the number of threads is
limited to a low number, the tradoff in favor of the stack seems
reasonable.

6) Separates and heirarchicalizes (sic) the SIM and APP filesystem
code. SIM path and volume handling is just like the target. Some
aspects of the APP file code get more straightforward (e.g. no path
hashing is needed).

Dircache:
Deserves its own section. Dircache is new but pays homage to the old.
The old one was not compatible and so it, since it got redone, does
all the stuff it always should have done such as:

1) It may be update and used at any time during the build process.
No longer has one to wait for it to finish building to do basic file
management (create, remove, rename, etc.).

2) It does not need to be either fully scanned or completely disabled;
it can be incomplete (i.e. overfilled, missing paths), still be
of benefit and be correct.

3) Handles mounting and dismounting of individual volumes which means
a full rebuild is not needed just because you pop a new SD card in the
slot. Now, because it reuses its freed entry data, may rebuild only
that volume.

4) Much more fundamental to the file code. When it is built, it is
the keeper of the master file list whether enabled or not ("disabled"
is just a state of the cache). Its must always to ready to be started
and bind all streams opened prior to being enabled.

5) Maintains any short filenames in OEM format which means that it does
not need to be rebuilt when changing the default codepage.

Miscellaneous Compatibility:
1) Update any other code that would otherwise not work such as the
hotswap mounting code in various card drivers.

2) File management: Clipboard needed updating because of the behavioral
changes. Still needs a little more work on some finer points.

3) Remove now-obsolete functionality such as the mutex's "no preempt"
flag (which was only for the prior FAT driver).

4) struct dirinfo uses time_t rather than raw FAT directory entry
time fields. I plan to follow up on genericizing everything there
(i.e. no FAT attributes).

5) unicode.c needed some redoing so that the file code does not try
try to load codepages during a scan, which is actually a problem with
the current code. The default codepage, if any is required, is now
kept in RAM separarately (bufalloced) from codepages specified to
iso_decode() (which must not be bufalloced because the conversion
may be done by playback threads).

Brings with it some additional reusable core code:
1) Revised file functions: Reusable code that does things such as
safe path concatenation and parsing without buffer limitations or
data duplication. Variants that copy or alter the input path may be
based off these.

To do:
1) Put dircache functionality back in the sim. Treating it internally
as a different kind of file system seems the best approach at this
time.

2) Restore use of dircache indexes in the playlist and database or
something effectively the same. Since the cache doesn't have to be
complete in order to be used, not getting a hit on the cache doesn't
unambiguously say if the path exists or not.

Change-Id: Ia30f3082a136253e3a0eae0784e3091d138915c8
Reviewed-on: http://gerrit.rockbox.org/566
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested: Michael Sevakis <jethead71@rockbox.org>

* Seal away private thread and kernel definitions and declarations
into the internal headers in order to better hide internal structure.

* Add a thread-common.c file that keeps shared functions together.
List functions aren't messed with since that's about to be changed to
different ones.

* It is necessary to modify some ARM/PP stuff since GCC was complaining
about constant pool distance and I would rather not force dump it. Just
bl the cache calls in the startup and exit code and let it use veneers
if it must.

* Clean up redundant #includes in relevant areas and reorganize them.

* Expunge useless and dangerous stuff like remove_thread().

Change-Id: I6e22932fad61a9fac30fd1363c071074ee7ab382

The code was broken in a subtle but crucial way: storage idle
callbacks are oneshot so after the first flush everything would
stay in the buffer forever and would never be written to the disk
thus resulting into many events being lost. This changed correctly
registers the idle callback each time the buffer is not empty.
Note that the idle storage code checks if a callback
has is in the queue already so we don't register twice.

Change-Id: Ifdf331d4b757e05b8a6902bf5926cbc7689f5109

* Remove explicit tracking of elapsed time of previous track.
* Remove function to obtain auto skip flag.
* Most playback events now carry the extra information instead and
  pass 'struct track_event *' for data.
* Tweak scrobbler to use PLAYBACK_EVENT_TRACK_FINISH, which makes
  it cleaner and removes the struct mp3entry.

Change-Id: I500d2abb4056a32646496efc3617406e36811ec5

Change-Id: I4adb8a152e9b99fcd26d95da7334d7d0cbe2a036

Eliminates the pcmrec thread and keeps playback and recording engine
operation mutually-exclusive.

audio_thread.c contains the audio thread which branches to the
correct engine depending upon the request. It also handles the main
audio initialization.

Moves pcm_init into main.c just before dsp_init because I don't want
that one in audio_init in the new file.

(Also makes revision df6e1bc pointless ;)

Change-Id: Ifc1db24404e6d8dd9ac42d9f4dfbc207aa9a26e1

Logs information, errors, etc to disk using the register_storage_idle_func
mechanism to write to the disk when available.  Currently, this is disabled
in normal builds, but can be enabled by adding ROCKBOX_HAS_LOGDISKF to the
config file.  By default, it uses a 2KB buffer and drops text if the buffer
overflows.

The system includes a simple warning level mechanism that can be used to by
default exclude non-serious errors from logging on release builds.

Change-Id: I0a3d186a93625c7c93dae37b993a0d37e5a3a925
Reviewed-on: http://gerrit.rockbox.org/288
Reviewed-by: Jonathan Gordon <rockbox@jdgordon.info>
Tested-by: Michael Giacomelli <mgiacomelli@gmail.com>
Reviewed-by: Michael Giacomelli <mgiacomelli@gmail.com>