[topgen] Allow named bus interfaces to connect to crossbar

The big change here is in topgen, where we teach it to cope with
wiring up named devices. To do so, incorporate each module's
bus_interfaces field into its instances and then use that field to
figure out how connections should work.

To refer to named interfaces in the crossbar file, use the syntax
"<instance>.<iface_name>" for the name of the entry in the node list
and for entries in the connections lists.

To test this, I edited OTBN's bus_interfaces list to look like this:

   bus_interfaces: [
    { protocol: "tlul", direction: "device", name: "cabbage" }
   ],

and renamed the corresponding ports in otbn.sv accordingly:

    input  tlul_pkg::tl_h2d_t cabbage_tl_i,
    output tlul_pkg::tl_d2h_t cabbage_tl_o,

The only other change needed is to the wiring in xbar_main.hjson (as
you'd expect, since the target has changed). Here we edit the list of
connections to replace "otbn" with "otbn.cabbage". Once everything is
re-generated, we get a load of signals with names involving
"otbn__cabbage" (replacing "." with "__") and everything seems to be
wired up correctly.

Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
13 files changed
tree: 22a26b14d58f2357acf9999f98db4aec588b298f
  1. .github/
  2. ci/
  3. doc/
  4. hw/
  5. site/
  6. sw/
  7. test/
  8. util/
  9. .clang-format
  10. .dockerignore
  11. .flake8
  12. .gitignore
  13. .style.yapf
  14. .svlint.toml
  15. .svls.toml
  16. _index.md
  17. apt-requirements.txt
  18. azure-pipelines.yml
  19. check_tool_requirements.core
  20. CLA
  21. COMMITTERS
  22. CONTRIBUTING.md
  23. LICENSE
  24. meson.build
  25. meson_init.sh
  26. meson_options.txt
  27. python-requirements.txt
  28. README.md
  29. tool_requirements.py
  30. toolchain.txt
  31. topgen-generator.core
  32. topgen-reg-only.core
  33. topgen.core
  34. yum-requirements.txt
README.md

OpenTitan

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About the project

OpenTitan is an open source silicon Root of Trust (RoT) project. OpenTitan will make the silicon RoT design and implementation more transparent, trustworthy, and secure for enterprises, platform providers, and chip manufacturers. OpenTitan is administered by lowRISC CIC as a collaborative project to produce high quality, open IP for instantiation as a full-featured product. See the OpenTitan site and OpenTitan docs for more information about the project.

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