FreeCalypso Tourmaline firmware project
=======================================

In chronological terms, FC Tourmaline is our fourth firmware offering after
Citrine, Magnetite and Selenite.  FC Tourmaline supports the following two
fundamental modes of operation:

* AT-command-controlled modem operation (no UI) is currently unchanged from
  Magnetite hybrid; standard modem operation is supported on Tango/Caramel2,
  FCDEV3B and Openmoko hardware targets.

* The new work being done in Tourmaline is phone handset functionality - the
  goal is to produce firmware that can operate a suitable hardware unit as an
  untethered end user phone.  Only two hardware targets are supported in this
  FC Tourmaline handset UI development venture: FC Luna development platform
  and Motorola C139.

See the following articles under doc for further details:

C139-notes		-- running smallbw version of the UI on Mot C139
Luna-notes		-- running both UI versions on FC Luna
Modem-operation		-- using the modem configuration

Technical details
=================

Just like FC Selenite, Tourmaline is derived from the hybrid config of
Magnetite.  Also in common with Selenite, Tourmaline uses the new source
version of Nucleus.  However, unlike Selenite, Tourmaline retains sole use of
the original TMS470 compiler (runs under Wine), retains the original blob
versions of OSL and OSX glue components of GPF in the default config (see
doc/Blob-status), and includes both modem and handset functional configs.

Purpose and goal
================

As of late 2020, FreeCalypso has achieved everything that needs to be done on
the modem side: our Magnetite hybrid or Tourmaline stdmodem firmware running on
our Tango modem module embodies complete fulfillment of our long-standing desire
for a standard GSM+GPRS modem module with fully published circuit schematics and
firmware source code.  No more significant work beyond maintenance is deemed to
be needed on the modem side.

OTOH, the other need for a FreeCalypso handset that can replace proprietary
phones like Mot C1xx or Pirelli DP-L10 running their original proprietary fw
still remains as unmet as it was when we started back in 2013.  Thus the new
FreeCalypso work direction is to finally produce this FC handset, initially in
the form of FC firmware running on Mot C139 (and on FC Luna to keep up the
bigcolor config) and allowing the possibility of new FreeCalypso handset hw.

Seen from the perspective of handset rather than modem functionality, the
direction taken in Citrine and Selenite (going for 100% blob-free compilation
with gcc) is the wrong way to go.  That direction would make sense if one cared
only about modem functionality rather than handset, but we are currently in the
opposite situation.  In the case of handset functionality, going for a compiler
change to gcc in our current state when so many other parts are broken and in
need of fixing would be pure insanity, and we are not going there.  Let us
first produce a working FreeCalypso handset (with fw compiled with TMS470 under
Wine, keeping the tiny remaining blobs) that can replace Mot/Pirelli's original
proprietary firmwares for daily use, and *then* think about moving to 100%
blob-free gcc - in this order.