feat: check pin G13 for host boot complete

[eigen-value]

No description provided.

[sebromero]

Maybe we should consider extracting this from begin() into its own function e.g. ready(). That way the bridge could be started using begin() and the time during which Linux boots could be used to prepare other peripherals etc. instead of wasting it and then when that is done, the sketch can wait for Linux using ready(). @facchinm

[eigen-value]

@sebromero I understand your point, but I have mixed feelings about it.
That way we can't always make sure Bridge is used before the other side is ready (eg somebody could try and use Monitor to println during peripherals setup).
Besides we complicate the UX adding yet another call before exiting setup.

[sebromero]

@eigen-value What if we do the following: begin() can stay blocking as it currently is waiting for Linux to boot, but we extract that check into its own non-blocking function e.g. ready(). The user has the option of preparing as much peripherals, buffering sensor data etc. as they can while Linux is being booted and just check periodically if Linux is ready and then start the bridge using begin(). That way the boot up time optionally be used for something useful without compromising the UX. As soon as begin() is called the user HAS to (busy)-wait for the boot-up to finish. In other words, advanced users have the option of calling the begin() function only when they know for sure the system has booted.

[eigen-value]

Hi @sebromero, @pennam
It makes sense so check the latest commit please.
It works with the bricks, but must be tested in the "Startup mode->Immediate" scenario

Before marking the PR as ready I need to check If G13 is raised from a specific RC onward and if a timeout is needed for backwards compat

[sebromero]

Correct me if I'm wrong but I think ready also needs to call init, otherwise mpu_boot_pin won't be configured correctly if ready is being called standalone. The mutex wouldn't necessarily be required by ready, so maybe the pin needs its own init function?

[github-actions]

Memory usage change @ 1b14cf9

Board	flash	%	RAM for global variables	%
arduino:zephyr:unoq	🔺 +184 - +248	+0.01 - +0.01	🔺 +16 - +16	0.0 - 0.0

Click for full report table

Board	examples/client flash	%	examples/client RAM for global variables	%	examples/clientSSL flash	%	examples/clientSSL RAM for global variables	%	examples/hci flash	%	examples/hci RAM for global variables	%	examples/monitor flash	%	examples/monitor RAM for global variables	%	examples/server flash	%	examples/server RAM for global variables	%	examples/simple_bridge flash	%	examples/simple_bridge RAM for global variables	%	examples/test flash	%	examples/test RAM for global variables	%
arduino:zephyr:unoq	236	0.01	16	0.0	236	0.01	16	0.0	244	0.01	16	0.0	248	0.01	16	0.0	236	0.01	16	0.0	184	0.01	16	0.0	244	0.01	16	0.0

Click for full report CSV

Board,examples/client<br>flash,%,examples/client<br>RAM for global variables,%,examples/clientSSL<br>flash,%,examples/clientSSL<br>RAM for global variables,%,examples/hci<br>flash,%,examples/hci<br>RAM for global variables,%,examples/monitor<br>flash,%,examples/monitor<br>RAM for global variables,%,examples/server<br>flash,%,examples/server<br>RAM for global variables,%,examples/simple_bridge<br>flash,%,examples/simple_bridge<br>RAM for global variables,%,examples/test<br>flash,%,examples/test<br>RAM for global variables,%
arduino:zephyr:unoq,236,0.01,16,0.0,236,0.01,16,0.0,244,0.01,16,0.0,248,0.01,16,0.0,236,0.01,16,0.0,184,0.01,16,0.0,244,0.01,16,0.0