ot_spi_device: Implement the TPM mode

[engdoreis]

ThIs PR does not cover all the TPM implementation, the HW registers will be covered by a follow up PR.

To test use the Opentitan PR lowRISC/opentitan#28542 and run:

bazel test --test_output=streamed --build_tests_only \
    $(bazel query //sw/device/tests:all | grep qemu | grep spi_device) \
    --test_tag_filters="qemu" --override_repository="+qemu+qemu_opentitan=$qemu_repo"

[rivos-eblot]

I'll review it soon; I've noticed there are a couple of type mismatches (e.g. bool x; ... x = 1;) and missing unsigned constant suffixes (u)

[rivos-eblot]

see also the PR title, as they now follow the

`component`: ...

formatting, i.e. ot_spi_device: Implement the TPM mode

[AlexJones0]

I got part way through reviewing but then @engdoreis told me this is still being actively worked on as a draft. I'll leave the comments I had for now though to aid development, but I haven't looked at any of the TPM logic itself yet.

[rivos-eblot]

Note: I would recommend to add new trace_ot_spi_device_...
Traces are very useful for debugging the emulation itself, but they are also very useful when developping guest SW (RISC-V code) and remote host peer SW. Thanks.

[rivos-eblot]

Two remaining items:

• static assertion location
• emptying TPM FIFO @ reset.

[rivos-eblot]

see also the PR title, as they now follow the

`component`: ...

formatting, i.e. ot_spi_device: Implement the TPM mode

nit pick: you still need to update your PR titke

[rivos-eblot]

LGTM

[AlexJones0]

Thanks, this generally LGTM after addressing my final comments. I haven't cross-referenced the implementation against the TPM spec, but a passing TPM test provides confidence.

On that note, when I checkout your OpenTitan PR and run the provided command the test does not pass, it just gets stuck after Iteration 0 and times out. Is there something I'm missing, was there a regression while making the fixes or is there something else happening? Nevermind, I didn't realize that my override path was different. It works when I override QEMU properly 😅 I'm happy after these 2 comments are addressed.

[rivos-eblot]

See SPI device regression introduced with this PR: #266