Add top_layer/pg_pins_layers/stripe_pins flags to write_ilm for hierarchical flows

[jerryz123]

Related PRs / Issues

Type of change:

• Bug fix
• New feature
• Other enhancement

Impact:

• Change to core Hammer
• Change to a Hammer plugin
• Other

Contributor Checklist:

• Did you set master as the base branch?
• Did you state the type-of-change/impact?
• Did you delete any extraneous prints/debugging code?
• (If applicable) Did you add documentation for the feature?
• (If applicable) Did you update the poetry.lock file if you updated the requirements in pyproject.toml?
• (If applicable) Did you add a unit test demonstrating the PR?
• (If applicable) Did you run this through the e2e integration tests?
• (If applicable) Did you update the submodules in e2e/ if this feature depends on updated plugins?

[harrisonliew]

Hm, can't we just set the stripe pins and top layer arguments based on the power straps pin_layer field?

[jerryz123]

Is that general enough though for all use cases? For instance, If you have a power island in a block that instantiates its own bump, what would the flags to this command need to be?

I figured there will frequently be cases where you'll need some specialized settings to achieve what you want.

[harrisonliew]

In the user guide:

In a bottom-up flow (where the block was not created using the create_partition command), you normally create a simple LEF abstract that contains:

• one obstruction (OBS) shape per routing layer
• signal pins located along the block boundary
• add power pins for the top metal layer PG stripes (see –stripe_pins and –pg_pin_layers options)
• embedded bump pins shapes are also written out as LEF pin shapes

So, it seems like -stripe_pins and -pg_pin_layers is sufficient. If you want more options, that's what a replacement hook is for. Otherwise adding all these keys for command options gets unwieldy.

[jerryz123]

Ok, I'll change this then.

[jerryz123]

Should we at least handle the case where manual power straps are used, in which case the by_tracks.pin_layers option is unset?

[harrisonliew]

No, I think if you're doing manual straps, you're already using hooks and being mindful of stripe pin layers. At most, add an additional comment for the by_tracks.pin_layers key to note that this is used when writing out LEF/DEF of the layout (user can always set this key even if they're using manual straps).