[sw/silicon_creator] Implement ROM_EXT bootstrap library

[dmcardle]

No description provided.

[alphan]

Thanks a lot for putting this together @dmcardle ! I'm just not sure about the following points:

• Can we try splitting this into two implementations like rom and rom_ext so that we don't have to cache and pass protect_rom_ext to the functions?
• I think we should enhance the flash_ctrl.c driver and add a function for setting mp_region_cfg registers for enabling erase over an arbitrary region instead of enabling it for a bank -- this would handle protecting rom_ext as well.
• We should double-check with rom_ext is at a page boundary. If not, we will need to read-modify-write since we can only erase at page boundaries.

I'll send an invite to chat about this tomorrow.

[alphan]

Suggested change

OT_DISCARD(rom_printf("Entering ROM_EXT bootstrap\r\n"));

[dmcardle]

So this printf is not strictly necessary, but I figured it simplifies testing rom_ext_bootstrap_enabled() via a functest, since we can set the exit_success to "Entering ROM_EXT bootstrap\r\n".

Deleting is fine as well — e2e tests can just test the observable behavior, such as whether the requested pages were written to flash.

[alphan]

So this printf is not strictly necessary, but I figured it simplifies testing rom_ext_bootstrap_enabled() via a functest, since we can set the exit_success to "Entering ROM_EXT bootstrap\r\n".

I see.

Deleting is fine as well — e2e tests can just test the observable behavior, such as whether the requested pages were written to flash.

I think we can also send jedec_id or read_sfdp commands and check the response.

If you prefer to include this please feel free to add a fpga-specific function implementation in device_fpga_cw310.c. You might also want to convert the existing function to a generic fpga_rom_printf(). But please note that if you use it in tests those tests would pass only on FPGA.

[dmcardle]

Hey @alphan, this is ready to review whenever you get a chance!

• Can we try splitting this into two implementations like rom and rom_ext so that we don't have to cache and pass protect_rom_ext to the functions?

Done.

• I think we should enhance the flash_ctrl.c driver and add a function for setting mp_region_cfg registers for enabling erase over an arbitrary region instead of enabling it for a bank -- this would handle protecting rom_ext as well.

Per our chat, I'll enhance the flash_ctrl driver in a followup PR. This PR has unit tests that verify/document the non-bounds-checking behavior. I've left TODO comments (linking to #19151) about making use of the flash_ctrl memory protection features. I'll sweep through and clean out those TODOs in the followup PR.

• We should double-check with rom_ext is at a page boundary. If not, we will need to read-modify-write since we can only erase at page boundaries.

Good point. The ROM_EXT regions in slot A and slot B definitely lie on page boundaries. I'll plan on adding a static_assert in the followup PR.

• CHIP_ROM_EXT_SIZE_MAX is 0x10000
• FLASH_CTRL_PARAM_BYTES_PER_BANK is 524288
• FLASH_CTRL_PARAM_BYTES_PER_PAGE is 2048

$ python
>>> 524288 % 2048
0
>>> 0x10000 % 2048
0
>>> (524288 + 0x10000) % 2048
0

[alphan]

Thanks @dmcardle ! LGTM mod some minor nits.