jetson-derive-carrier

Customize first-run gate for any customize-* skill on a custom carrier. Resolve the active target per target-platform-contract.md. Refuse if no custom_carrier: block, or if <source.root_path>/Linux_for_Tegra/.git is missing (jetson-init-source first). Template file create/copy rows land in a single overlay-tracker commit and copy directly to the custom-carrier-renamed target path — reference-named pristine files are never staged (see Fork plan for the local rule, which overrides the standard pristine + customization split from the workflow); conf-chain discovery follows per-board conf dispatch. Kernel base DTB is not forked — carrier deltas layer as a DT overlay wired via OVERLAY_DTB_FILE.

Identifiers (from active profile): <chip> from reference_devkit.module.id via catalogue (unknown → warn, fallback tegra234); <module-id>/<module-sku> from reference_devkit.module; <carrier-id>/<carrier-sku> from reference_devkit.carrier; <custom-id>/<custom-sku>/ <custom-flash-conf> from custom_carrier. <real-conf> = readlink <bsp_image.root_path>/Linux_for_Tegra/<reference_devkit.flash_config> (NVIDIA convention <devkit>.conf → <carrier>-<module>-a<rev>.conf; warn + treat top-level as real + skip symlink-wrapper row if not a symlink).

<custom-id> is a custom carrier board token, not necessarily an NVIDIA-style pNNNN ID. Use it verbatim in dash-form filenames and DT compatible strings. When a target file family uses p-stripped numeric tokens, derive <custom-id-file-token> as NNNN only if <custom-id> matches ^p[0-9]{4}$; otherwise use <custom-id> unchanged. Do not reject custom carrier IDs merely because they do not start with p.

Instructions

The fork plan below is the instruction set: one discovery pass, then a row-by-row fork of the per-board fileset, gated by the commit-message preview before each git commit.

Fork plan

Every git commit produced by this skill — in the overlay tracker (Linux_for_Tegra/) or the hardware/ source repo — runs through the commit message preview gate. Surface the staged file list + proposed message to the operator and require accept / edit / cancel before each git commit; on cancel leave the index staged for manual resolution.

Materialize renamed forks even when bytes do not change. For every accepted fork-plan row, create and track the custom-carrier target path; do not skip a missing target because the fork is only a rename/copy or is byte-identical to the reference. This includes BCT forks such as pinmux, GPIO/GPIOINT, padvoltage/PMC, misc, and MB2 misc. Skip only when the Acceptance column allows it, the source is an explicit warn-and-skip miss, or the expected target path is already tracked; in the last case, report it as already derived and do not create an empty commit.

Template file create/copy rows squash into one overlay-tracker commit, and reference-named pristine files are never staged. All rows that materialize a new (template-derived) file in the overlay tracker — board flash-conf, flash-conf symlink, MB1 BCT (pinmux, GPIO/GPIOINT, padvoltage/PMC, misc), MB2 BCT (misc), BPMP DTB (when opted in), nvpmodel, nvfancontrol — copy directly from <bsp_image.root_path>/Linux_for_Tegra/<rel>/<reference-name> to <source.root_path>/Linux_for_Tegra/<rel>/<custom-name> with any content edits applied before staging. The reference-named (<carrier-id>-<carrier-sku>-keyed) filename is never staged or committed in the overlay tracker — only the custom-carrier-renamed file is tracked. This overrides the standard pristine + customization split from commit batching. All such rows land in a single overlay-tracker commit that adds: (i) the custom-carrier-named files at their target paths with content already applied, (ii) the flash-conf symlink, and (iii) the targeted flash-conf content rewrites inside the renamed flash-conf for PINMUX_CONFIG / GPIO_CONFIG / GPIOINT_CONFIG / PMC_CONFIG / MISC_CONFIG / MB2_BCT (plus BPFDTB_FILE when BPMP DTB is opted in). Rows that edit existing upstream files instead of creating templates — the nvpower.sh patch — and the overlay wire-up (OVERLAY_DTB_FILE+= append to the just-created flash-conf fork, treated as a temporally distinct phase per commit batching) remain separate commits per their own rows. The DT overlay skeleton commits in bsp_sources/hardware/, not the overlay tracker, so it is unaffected. The commit message preview gate fires once on the squashed commit; warn-and-skipped rows do not contribute, and if every row in the bundle is already tracked the commit is omitted entirely.

Discovery (single batched pass)

Run one discovery pass; do not interleave with staging. Do not truncate listings — every candidate filename in each scanned directory must be visible to the matcher. head, tail, | head -N, | tail -N, and any other row-limiting filter are out of bounds for this step; use ls -1 / find unclipped, or grep on the full output. Truncating risks false warn-and-skip calls when the matching file sits past the cutoff. Capture:

• Flash-conf vars: DTB_FILE / TBCDTB_FILE / BPFDTB_FILE / PINMUX_CONFIG / PMC_CONFIG / GPIO_CONFIG / GPIOINT_CONFIG. DTB_FILE / TBCDTB_FILE are captured for reference only so the overlay wire-up can derive <dtb-stem> for the overlay filename — they are never rewritten by this skill.
• BCT .dts at bootloader/generic/BCT/; .dtsi siblings live one level up at bootloader/ — NOT alongside.
• nvpmodel: nvpmodel_<module-id>_<module-sku>*.conf. nvfancontrol: nvfancontrol_<module-id>_<module-sku>_<carrier-id>_<carrier-sku>.conf.
• nvpower.sh anchors for (a)–(d): <carrier-id> cvb branch, <module-id>-<module-sku> SKU elif, tegra<chip> nvpmodel cascade, tegra<chip> nvfancontrol cascade.

¶ #include follow. Scan each captured .dts for #include "..." directives anywhere in the file (NVIDIA BSPs put them inside BCT node bodies); carrier-keyed includes join the fork list. Stop at one level.

† Rename rule. Carrier-keyed source (e.g. …-p3834-xxxx-p4071-0000.dts) → filename sub <carrier-id>-<carrier-sku> → <custom-id>-<custom-sku>; rewrite the flash-conf variable (e.g. PINMUX_CONFIG) to the renamed filename in the same customization commit. Module portion is preserved verbatim from pristine — if pristine has p3834-xxxx, fork keeps p3834-xxxx; if pristine has p3834-0008, fork keeps p3834-0008. Never pin module-SKU on your own. Same rule for any other xxxx wildcard in the carrier-SKU position when pristine uses it (e.g. p4071-xxxx → p1234-xxxx). Module-keyed source (e.g. …-p3767-dp-a03.dtsi) → append _<custom-id-file-token>_<custom-sku> (underscore-form) or -<custom-id>-<custom-sku> (dash-form) plus an extra commit on flash-conf fork rewriting the variable (e.g. PINMUX_CONFIG) to the suffixed name. Content never substituted by default; prompt if content holds a literal carrier-id-sku self-reference.

‡ Overlay skeleton. DT plugin overlay (/plugin/;) with one fragment@0 at target-path = "/"; inside __overlay__ set model = "<custom_carrier.name> carrier board" and compatible = "nvidia,<custom-id>-<custom-sku>+<module-id>-<module-sku>", "nvidia,<chip>". nvpower.sh machine narrowing reads compatible.

Edit verification

Re-grep after every sed / patch. sed silently no-ops on miss; exit code 0 proves nothing. Multi-line replacements: use Python str.replace(old, new), not multi-line sed (brittle to whitespace drift, silent no-ops). Refuse to commit on verification miss.

Summary. Print forks per repo (count + commit SHAs), BPMP-DTB decision, warn-and-skipped rows (mandatory source file missing on this BSP — don’t fail the run), overlay path written.

Examples

Trigger phrases the operator might use:

derive custom carrier
bootstrap custom carrier
fork carrier board from reference devkit

Minimal custom_carrier: block in the active profile that the skill expects to find:

custom_carrier:
  id: p1234            # any token; need not be NVIDIA pNNNN style
  sku: 0000
  flash_config: p1234.conf
  name: Acme Custom Carrier

Purpose

Customize the per-board fileset for a new carrier board so downstream customize-* skills, nvpower.sh, and the boot chain land on the custom carrier instead of the reference devkit. Base DTB stays at the reference; carrier deltas live in a DT overlay so a re-derive against a new reference BSP only needs to re-run this skill.

Prerequisites

• Active profile resolved per target-platform-contract.md with a custom_carrier: block (id, sku, flash-conf, friendly name).
• source.root_path/Linux_for_Tegra/.git initialized — run /jetson-init-source first; this skill refuses if the overlay tracker is missing.
• bsp_image.root_path populated by /jetson-init-image so the reference flash-conf symlink can be resolved.
• reference_devkit: populated (module + carrier) so the rename rule has carrier-id/sku tokens to substitute away from.

Limitations

• Kernel base DTB and its source DTS are not forked — carrier deltas must layer through the DT overlay wired via OVERLAY_DTB_FILE.
• BPMP DTB fork is opt-in (default OFF). Most carrier swaps share the reference BPMP DTB; only opt in when board power/clock topology diverges.
• Flash-conf content substitution is targeted, not blanket. Vars whose files this skill does not fork (DTB_FILE, TBCDTB_FILE, SCR_CONFIG, PMIC_CONFIG, DEVICEPROD_CONFIG, PROD_CONFIG, MINRATCHET_CONFIG, UPHY_CONFIG, dynamic OVERLAY_DTB_FILE+=) stay at reference values — rewriting them would point at files that do not exist.
• Custom-carrier IDs need not follow NVIDIA pNNNN style; the p-stripped numeric token is derived only when the ID matches ^p[0-9]{4}$.
• Does not customize module-level files. Use the relevant jetson-customize-* skill for pinmux, clocks, fan curves, nvpmodel, PCIe, UPHY, USB, MGBE, or camera deltas.

Troubleshooting

• Refuses with “no custom_carrier: block” — declare the block in the active profile before re-running; the skill will not infer it.
• Refuses with “.git missing in Linux_for_Tegra/“ — overlay tracker not initialized. Run /jetson-init-source first.
• ”<real-conf> not a symlink” — NVIDIA convention is a <devkit>.conf symlink to <carrier>-<module>-a<rev>.conf; if the top-level is the real conf, the skill warns, treats it as real, and skips the symlink-wrapper row. Not an error.
• sed reported success but the edit is missing — sed silently no-ops on miss. The skill re-greps after every patch and refuses to commit on verification miss; for multi-line replacements switch to Python str.replace.
• “chip: unknown” / fallback to tegra234 — module ID is not in the catalogue; update the catalogue rather than override in the profile.
• Commit message preview prompt blocks the run — expected gate per commit-batching; accept, edit, or cancel. On cancel the index is left staged for manual resolution.
• A mandatory source file is missing on this BSP — the row is recorded as warn-and-skipped in the summary; the rest of the run still completes.