The following Bourne shell variables can be set on the ./configure.sh command
line to tweak the firmware build configuration:

ALLOW_CSIM_GSM

	Per TI's original design, the AT+CSIM command does not allow GSM APDUs
	of class 0xA0.  Openmoko found some need for them, and they patched
	their modem fw to allow these APDUs with AT+CSIM.  With our new hybrid
	modem fw this policy setting is configurable at build time; the default
	is ALLOW_CSIM_GSM=1 (GSM APDUs allowed).

DISABLE_SLEEP

	The general default is DISABLE_SLEEP=0, and the firmware automatically
	enables all of the chipset's available sleep modes on boot.  Setting
	DISABLE_SLEEP=1 causes all sleep modes to be disabled by default on
	boot (they can still be enabled with the AT%SLEEP command); this
	setting is needed for FCDEV3B V1 boards that have a hardware bug that
	causes breakage when sleep modes are enabled.

DSAMPLE_FULL_COLOR

	When the firmware's R2D component (normally present only in UI-enabled
	builds) is built for any target other than c139, one of TI's D-Sample
	framebuffer drivers is enabled: either color or B&W.  (The actual
	hardware pokes are omitted when the build target is anything other than
	dsample, but the framebuffer is still maintained in RAM.)  By default
	the color framebuffer driver is enabled; setting DSAMPLE_FULL_COLOR=0
	switches to the B&W framebuffer driver.  Both configurations are
	supported on FC Luna.

L1_DYN_DSP_DWNLD

	This setting enables TI's dynamic DSP patch download mechanism.  When
	the firmware is built for a Calypso target with DSP ROM version 36 in
	the silicon (all FreeCalypso-made hw and most of the supported legacy
	targets), L1_DYN_DSP_DWNLD is enabled by default and needs to be kept
	enabled for correct operation: the patch code we got from TI for this
	ROM is the dynamic download version, and the ARM-side L1 code expects
	all of these patches to be present, both the static part and the
	dynamic parts.  However, one can build our fw with L1_DYN_DSP_DWNLD=0
	for experimental testing, to see what breaks when the dynamic patches
	are omitted.

L1_VOICE_MEMO_AMR

	This setting enables or disables support in L1 and in the RiViera Audio
	Service for AMR voice memo recording and playback.  This code has not
	been properly studied yet and no test AT commands are provided for it,
	but it is enabled by default like in TI's original TCS211 fw.

MELODY_E2

	This setting enables or disables support in L1 and in the RiViera Audio
	Service for playing E2-format melodies.  The default is MELODY_E2=1
	like in TI's original TCS211 fw.  Note that Melody E1 support is always
	enabled; setting MELODY_E2=0 disables only Melody E2, but not E1.

RVTMUX_ON_MODEM

	This setting configures the usage of Calypso UARTs.  RVTMUX_ON_MODEM=0
	puts the AT command interface on the MODEM UART and RVTMUX on the IrDA
	UART (TI's intended config and the default on sensible hw targets);
	RVTMUX_ON_MODEM=1 (default on the crippled C1xx targets) puts RVTMUX on
	the MODEM UART, sacrificing the standard AT command interface.

SERIAL_DYNAMIC_SWITCH

	TI's TCS211 fw includes a provision (only for Bluetooth-enabled fw in
	TI's original) to switch one UART between the AT command interface and
	RVTMUX while the other UART is fixed for Bluetooth.  In FreeCalypso we
	have changed this code to work without Bluetooth, for the purpose of
	switching the user-facing MODEM UART between AT commands and RVTMUX,
	but the mechanism does not work properly yet and is disabled by default.
	Enable it with SERIAL_DYNAMIC_SWITCH=1 if you would like to play with
	it.

SPEECH_RECO

	This setting enables or disables support in L1 and in the RiViera Audio
	Service for TI's speech recognition mechanism.  This code and the
	underlying DSP facility itself have not been properly studied yet and
	no test AT commands are provided for it, but it is enabled by default
	like in TI's original TCS211 fw.

SUFFIX

	This setting is solely for configuration management.  If you make a
	build with any of the settings described in this document changed from
	the default, you should also pass a SUFFIX=-xxx argument so your special
	build will be appropriately identified in the build directory name and
	in the firmware version ID string compiled into the image.  The naming
	of suffixes is up to you, but here are some examples:

	DISABLE_SLEEP=1 SUFFIX=-nosleep
	DSAMPLE_FULL_COLOR=0 UI_CONFIG=bigbw SUFFIX=-bw
	L1_DYN_DSP_DWNLD=0 SUFFIX=-nodyn
	MELODY_E2=0 SUFFIX=-noe2
	SERIAL_DYNAMIC_SWITCH=1 SUFFIX=-sds
	SPEECH_RECO=0 SUFFIX=-nosr
	TI_PROFILER=1 SUFFIX=-prf
	TR_BAUD_CONFIG=TR_BAUD_812500 SUFFIX=-812500
	USE_STR2IND=1 SUFFIX=-s2i

TI_PROFILER

	TI's original firmware architecture had a built-in profiler (program
	counter sampler) enabled with TI_PROFILER=1; we (FreeCalypso) are just
	beginning to experiment with this debug feature in late 2020.

TRACEMASK_IN_FFS

	TI's Test Interface (TIF) component in the GPF realm includes an
	optional feature for saving trace masks in FFS, but TI's production
	firmwares had it disabled.  We have now switched to recompiling the
	component in question from source, but we still keep this
	TRACEMASK_IN_FFS code disabled by default, at least for now.
	Set TRACEMASK_IN_FFS=1 to enable this code in GPF.

TR_BAUD_CONFIG

	The value of this symbol is an alphanumeric keyword of the form
	TR_BAUD_xxxxxx; the default is TR_BAUD_115200.  See
	src/cs/drivers/drv_core/uart/traceswitch.h for the available baud rate
	choices; the most practical use is setting TR_BAUD_CONFIG=TR_BAUD_812500
	when you need to run the RVTMUX serial channel at the maximum possible
	baud rate.

UI_CONFIG

	The 3 allowed values for this setting are bigcolor, bigbw and 84x48,
	selecting one of the 3 UI configurations supported by TI's code.  The
	default is 84x48 when the firmware is built for target c139, otherwise
	(particularly for dsample, luna1 and luna2 targets) the default is
	bigcolor.

USE_STR2IND

	Unlike TI's original firmwares, we build without str2ind by default.
	You can enable str2ind with USE_STR2IND=1, but the time to build the fw
	will be significantly longer as the compiler has to be run twice for
	each C source file, with str2ind sandwiched in between.

The following Bourne shell variables are used inside the build system in the
individual component build recipes (components/*) but cannot be set on the
./configure.sh line because they are fixed in the overall fw build recipes
(configs/*):

GPRS

	Self-explanatory: enables or disables GPRS.

MMI

	TI's original config variable: MMI=0 for the AT-command-controlled
	modem configuration or MMI=2 for the UI-enabled configuration with
	BMI and MFW.

SRVC

	TI's original config variable, selects the presence or absence of data
	services other than GPRS as follows:

	SRVC=0: voice and SMS only
	SRVC=1: CSD and fax enabled
	SRVC=2: CSD enabled, but not fax

Finally, CHIPSET, DSP, RF and AMR variables reflect the physical configuration
of the selected target hw that no amount of software hacking can change.
(The AMR variable indicates the presence or absence of AMR support in the DSP.)