pdk: keep single patched standard cell model

Author: phsauter

.gitattributes

@@ -1,2 +1,2 @@
 # Preserve formatting in imported generated collateral.
-ihp13/pdk/verilog/sg13g2_stdcell_verilator.v whitespace=-trailing-space
+ihp13/pdk/verilog/sg13g2_stdcell.v whitespace=-trailing-space

ihp13/pdk/ORIGINS.md

@@ -18,12 +18,11 @@ Full license copies are in `licenses/LICENSE.sg13g2` and `licenses/LICENSE.sg13c
 | `lef/sg13cmos5l_tech.lef` | [IHP CMOS5L PDK: standard cells](https://github.com/IHP-GmbH/ihp-sg13cmos5l/tree/5958eb38973d5c56e7a26f65fc23d9f3a740ccd2/libs.ref/sg13cmos5l_stdcell) | Copyright IHP PDK Authors, Apache-2.0 |
 | `lef/bondpad*.lef`, `verilog/bondpad*.v`, and `gds/bondpad*.gds` | Croc-local collateral in this directory | Copyright 2024-2026 ETH Zurich and University of Bologna, SHL-0.51; see the repository [license](../../LICENSE.md) |
 
-`verilog/sg13g2_stdcell_upstream.v` is the unmodified IHP standard-cell model.
-`verilog/sg13g2_stdcell_verilator.v` is the checked-in derivative used for
+`verilog/sg13g2_stdcell.v` is the patched IHP standard-cell model used for
 public Verilator simulations. It is generated by applying
 [`ihp13/patches/0002-add-verilator-standard-cell-compatibility.patch`](../patches/0002-add-verilator-standard-cell-compatibility.patch)
-to the upstream model. `scripts/setup_technology.sh` repeats this generation
-and selects the derivative through `verilog/sg13g2_stdcell.v`.
+to the pinned upstream source. `scripts/update_pdk.sh` performs this update;
+the runtime setup script does not modify checked-in collateral.
 
 The two Croc-local bondpad GDS files are committed in `gds/`. IHP GDS files are
 not committed due to their size; `scripts/download_pdk_gds.sh` downloads the

ihp13/pdk/README.md

@@ -19,3 +19,8 @@ See `ORIGINS.md` for the source, pinned revision, copyright, and license of
 every collateral family. The IHP source repositories used for KLayout support
 remain in `ihp13/sg13g2` and `ihp13/sg13cmos5l`; they are not flow input paths
 for Liberty, LEF, Verilog, or GDS.
+
+Maintainers refresh generated public collateral with
+`scripts/update_pdk.sh`. It downloads the pinned SG13G2 standard-cell model
+and applies Croc's Verilator compatibility patch before replacing the
+committed model.