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

None of the Sony up to A15 seem to support RDS (they use either Si4702 or Si4708),
thus I did not add any code to support RDS.

Change-Id: I64838993b9705b36b94665f8470c7a89c772c961

* Editing a bunch of drivers' thread routines in order to
implement a new feature is tedious.

* No matter the number of storage drivers, they share one thread.
No extra threads needed for CONFIG_STORAGE_MULTI.

* Each has an event callback called by the storage thread.

* A default callback is provided to fake sleeping in order to
trigger idle callbacks. It could also do other default processing.
Changes to it will be part of driver code without editing each
one.

* Drivers may sleep and wake as they please as long as they give
a low pulse on their storage bit to ask to go into sleep mode.
Idle callback is called on its behalf and driver immediately put
into sleep mode.

* Drivers may indicate they are to continue receiving events in
USB mode, otherwise they receve nothing until disconnect (they
do receive SYS_USB_DISCONNECTED no matter what).

* Rework a few things to keep the callback implementation sane
and maintainable. ata.c was dreadful with all those bools; make
it a state machine and easier to follow. Remove last_user_activity;
it has no purpose that isn't served by keeping the disk active
through last_disk_activity instead.

* Even-out stack sizes partly because of a lack of a decent place
to define them by driver or SoC or whatever; it doesn't seem too
critical to do that anyway. Many are simply too large while at
least one isn't really adequate. They may be individually
overridden if necessary (figure out where). The thread uses the
greatest size demanded. Newer file code is much more frugal with
stack space. I barely see use crack 50% after idle callbacks
(usually mid-40s). Card insert/eject doesn't demand much.

* No forcing of idle callbacks. If it isn't necessary for one or
more non-disk storage types, it really isn't any more necessary for
disk storage. Besides, it makes the whole thing easier to implement.

Change-Id: Id30c284d82a8af66e47f2cfe104c52cbd8aa7215

We don't really know what those are supposed to do. They seem to change the
volume curve but it is not very clear what is the intended purpose.

Change-Id: I65f5d18aba139844c23df092277ba17ee8518f96

Change-Id: I335fcdbb652253e777d0d7406545d0d44d98f4f0

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

Change-Id: I54c681a9eb3d5e90ee4aeedc3ec5dbd6243cb208

Many includes of fat.h are pointless. Some includes are just for
SECTOR_SIZE. Add a file 'firmware/include/fs_defines.h' for that
and to define tuneable values that were scattered amongst various
headers.

Remove some local definitions of SECTOR_SIZE since they have to be
in agreement with the rest of the fs code anyway.

(We'll see what's in fact pointless in a moment ;)

Change-Id: I9ba183bf58bd87f5c45eba7bd675c7e2c1c18ed5

Also, use rds_reset() now to clear data on station change since
the rds driver internal buffers are used.

Change-Id: I043b09d661eeec21617381015347f0bcead4f7d4

* fmradio.c needs an implementation of tuner_get_rds_info() for the
sim (kill all the sims).

* Some macro bitflags shouldn't be seen unless HAVE_RDS_CAP is
defined.

Change-Id: Idd00c94ca2fc43cf32f9223aa4530d5a02fb3454