Caliptra 1.x watchdog config

[bgilsrudHPE]

Hi,
How is the SoC expected to configure the Caliptra watchdog? Also, why does the SoC configure this rather than the Caliptra boot ROM configuring it on it's own?

[dbids]

@mhatrevi What is the value expected or recommended to be for the watchdog timer?

[mhatrevi]

The duration required for the SOC to transmit a firmware image to the ROM via the mailbox interface is highly dependent on the specific SoC environment. A single value cannot adequately accommodate the variability across different SoC configurations. Therefore, it is recommended to test with a sufficiently large timeout value and subsequently fine-tune this parameter to optimize it for the particular SoC integration.

[bgilsrudHPE]

Is the purpose of the watchdog just to ensure the firmware download process completes within the configured time? It's not clear how the SoC can influence the Caliptra's ability to service its own watchdog timer. Should we just set this to something large (10 seconds? 100 seconds?) leave it be if we don't see Caliptra report watchdog timeouts?