This is a prerequisite for duke3d running on monochrome targets. It should
probably be made more fine-grained before it is merged, since I'm pretty
sure there were good reasons to limit it as before.

Change-Id: Ic4c90bd4e7071f82973bb4704b3d4dfb9ad15311

This ports Fabien Sanglard's Chocolate Duke to run on a version of SDL
for Rockbox.

Change-Id: I8f2c4c78af19de10c1633ed7bb7a997b43256dd9

Instead of checking ticks, set a sticky dirty flag that indicates
that the RTC needs to be read. This gives a timely update and more
accurate readout without actually reading the RTC until it changes.
The implementation should atomically read the flag and clear it.
Setting the flag would typically happen in an RTC tick ISR.

Change-Id: I6fd325f22845029a485c502c884812d3676026ea

Adds the ability to load firmware from other drives on MULTIVOLUME targets
Mihail Zenkov <mihail.zenkov@gmail.com> had posted a hard coded patch
to allow this on several Sansa players, I made it more universal

Redirect file rockbox_main.<name> should placed in root of
drive you would like to be main, if this file empty or there a single
slash '/' firmware will be loaded from /.rockbox in root of this drive
If instead a /<*DIRECTORY*> is supplied in rockbox_main.<name> then
firmware will be loaded from /<dir>/.rockbox/

NOTES*

The directory can have multiple levels however..
leading slash MUST be included
trailing slash can be omitted
(eg. /test/.rockbox would be simply '/test' in the redirect file)

Redirect file will not work on internal drive (whatever is default boot drive)

Volume with the highest index containing redirect file will be loaded
first.

Firmware file is checked for boot data region, if missing, firmware
image will not be loaded.

On failure or if no redirect file is found load will fallback to
internal drive

Currently only Sansa Fuze+, Sansa Clip+,
Sansa Clip Zip, Sansa Fuzev2, and Sansa Fuzev1 are implemented.

Players (with HAVE_MULTIVOLUME)
will need #define HAVE_BOOTDATA and #define BOOT_REDIR "rockbox_main.<name>"
added to their config file

boot_data is implemented in crt0.s file (See g#1552)
ARM and IMX233 have aleady been implemented

Once these conditions are met <HAVE_MULTIBOOT> will be defined by config.h

Partitions on the drives are able to have a redirect as
well.

Change-Id: Iada3263919f6bcad7d0d7d8279b4239aafa07ee9

Strangely it has the SAME encryption key as the E450. Either they didn't bother
changing it or more likely they have exactly the same internals and a slightly
different case.

Change-Id: I39ab88845b3e40db34160c2e61dde421f391df44

Change-Id: I9050129949809b3dbe9f4f9e816f8980c4f3a904

Change-Id: Ibf0c5168ac31d4ba2aeaa86cbeca37a1011b75fa

Add original author to CREDITS

Change-Id: I7a0159635c7896e2b5521c078ef62618f568d89e

SUPPORTED SERIES:
- NWZ-E450
- NWZ-E460
- NWZ-E470
- NWZ-E580
- NWZ-A10

NOTES:
- bootloader makefile convert an extra font to be installed alongside the bootloader
  since sysfont is way too small
- the toolsicon bitmap comes from the Oxygen iconset
- touchscreen driver is untested

TODO:
- implement audio routing driver (pcm is handled by pcm-alsa)
- fix playback: it crashes on illegal instruction in DEBUG builds
- find out why the browser starts at / instead of /contents
- implement radio support
- implement return to OF for usb handling
- calibrate battery curve (NB: of can report a battery level on a 0-5 scale but
  probabl don't want to use that ?)
- implement simulator build (we need a nice image of the player)
- figure out if we can detect jack removal

POTENTIAL TODOS:
- try to build a usb serial gadget and gdbserver

Change-Id: Ic77d71e0651355d47cc4e423a40fb64a60c69a80

* Remove unused bits like the radio event and simplify basic
radio interface. It can be more self-contained with rds.h only
required by radio and tuner code.

* Add post-processing to text a-la Silicon Labs AN243. The chip's
error correction can only do so much; additional checks are highly
recommended. Simply testing for two identical messages in a row
is extremely effective and I've never seen corrupted text since
doing that, even with mediocre reception.

Groups segments must arrive in order, not randomly; logic change
only accepts them in order, starting at 0.

Time readout was made a bit better but really we'd need to use
verbose mode and ensure that no errors were seen during receiving
of time and more checks would be need to have a stable PI. The
text is the important bit anyway.

* Time out of stale text.

* Text is no longer updated until a complete group has been
received, as is specified in the standard. Perhaps go back to
scrolling text lines in the radio screen?

* Add proper character conversion to UTF-8. Only the default G0
table for the moment. The other two could be added in.

* Add variants "RDS_CFG_PROCESS" and "RDS_CFG_PUSH" to allow
the option for processed RDS data to be pushed to the driver and
still do proper post-processing (only text conversion for now for
the latter).

Change-Id: I4d83f8b2e89a209a5096d15ec266477318c66925