[Integration spec] Document full cold boot flow from integrator perspective

[jhand2]

I wasn't able to find documentation of the things an integrator is supposed to do to boot Caliptra. Steps like:

1. Assert CPTRA_POWER_GOOD
2. Populate fuse registers
3. Write fuse_write_done register
4. Write BOOTFSM_GO register

Is this something that would make sense to document in the hardware integration spec.

[Nitsirks]

I think this figure in that doc is meant to detail that.

Figure 3: Reset rules and timing diagram

@bharatpillilli maybe we can be more explicit in the spec so the information is easier to find?

[jhand2]

Got it, that diagram is helpful. Ya I think it would be good to explicitly list what is expected from the SoC. In particular, I don't think it says the SoC needs to assert BOOTFSM_GO.

[bharatpillilli]

I think this figure in that doc is meant to detail that.

Figure 3: Reset rules and timing diagram

@bharatpillilli maybe we can be more explicit in the spec so the information is easier to find?

Ack Mike!

[bharatpillilli]

BootFSM Go is only required when HW Break point is set -otherwise it should not be gating

[jhand2]

BootFSM Go is only required when HW Break point is set -otherwise it should not be gating

Ah, I didn't know that. Thanks for the clarification.