--- name: jetson-derive-carrier description: >- Bootstrap a custom carrier board by forking carrier files and scaffolding a DT overlay from the reference devkit. Use after jetson-init-source; not for module-level or kernel-DTB changes. version: 0.0.1 license: "Apache-2.0" metadata: data-classification: public author: "Jetson Team" tags: - target-platform - custom-carrier - bring-up - setup domain: meta --- # jetson-derive-carrier Customize first-run gate for any `customize-*` skill on a custom carrier. Resolve the active target per [`target-platform-contract.md`](../../context/target-platform-contract.md). **Refuse** if no `custom_carrier:` block, or if `/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](#fork-plan) for the local rule, which overrides the standard pristine + customization split from the [workflow](../../context/bsp-customization-workflow.md#commit-batching-in-the-overlay-tracker)); conf-chain discovery follows [per-board conf dispatch](../../context/bsp-customization-software-layers.md#per-board-conf-dispatch--update_flash_args_common). Kernel base DTB is **not** forked — carrier deltas layer as a DT overlay wired via `OVERLAY_DTB_FILE`. **Identifiers** (from active profile): `` from `reference_devkit.module.id` via [catalogue](../../references/bsp-platforms-catalogue.md) (unknown → warn, fallback `tegra234`); ``/`` from `reference_devkit.module`; ``/`` from `reference_devkit.carrier`; ``/``/ `` from `custom_carrier`. `` = `readlink /Linux_for_Tegra/` (NVIDIA convention `.conf` → `--a.conf`; warn + treat top-level as real + skip symlink-wrapper row if not a symlink). `` 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 `` as `NNNN` only if `` matches `^p[0-9]{4}$`; otherwise use `` 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](../../context/bsp-customization-workflow.md#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 `/Linux_for_Tegra//` to `/Linux_for_Tegra//` with any content edits applied before staging. The reference-named (`-`-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](../../context/bsp-customization-workflow.md#commit-batching-in-the-overlay-tracker). 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](../../context/bsp-customization-workflow.md#commit-batching-in-the-overlay-tracker)) 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 `` 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__*.conf`. nvfancontrol: `nvfancontrol____.conf`. - `nvpower.sh` anchors for (a)–(d): `` cvb branch, `-` SKU `elif`, `tegra` nvpmodel cascade, `tegra` nvfancontrol cascade. | File / category | Discovery | Acceptance | Fork rule | |---|---|---|---| | Board flash conf | `` | Always | Filename sub `-` → `-`. Content sub is **targeted, not blanket**: rewrite RHS only for vars whose file this skill forks — `PINMUX_CONFIG`, `PMC_CONFIG`, `GPIO_CONFIG` / `GPIOINT_CONFIG`, `MISC_CONFIG`, `MB2_BCT`. Other carrier-keyed vars (`DTB_FILE`, `TBCDTB_FILE`, `SCR_CONFIG`, `PMIC_CONFIG`, `DEVICEPROD_CONFIG`, `PROD_CONFIG`, `MINRATCHET_CONFIG`, `UPHY_CONFIG`, dynamic `OVERLAY_DTB_FILE+=`) MUST stay at reference values — their files aren't forked here and a blanket `sed` would point them at nonexistent files. `DTB_FILE` / `TBCDTB_FILE` specifically: base DTB is not forked; the overlay row appends a new `OVERLAY_DTB_FILE+=` line instead. `BPFDTB_FILE`: opt-in extra commit. Never touch ``, ``, `xxxx`. | | Flash-conf symlink | Unconditional | Always (skip if `` not a symlink) | New symlink `` → flash-conf fork | | MB1 BCT pinmux | `PINMUX_CONFIG` + `#include` follow ¶ | Always | Rename rule † | | MB1 BCT GPIO | `GPIO_CONFIG`/`GPIOINT_CONFIG` + `#include` follow ¶ | Always | Rename rule † | | MB1 BCT padvoltage | `PMC_CONFIG` + `#include` follow ¶ | Always | Rename rule † | | MB1 BCT misc | `MISC_CONFIG` + `#include` follow ¶ | Always | Rename rule † | | MB2 BCT misc | `MB2_BCT` + `#include` follow ¶ | Always | Rename rule † | | Kernel DTB + source DTS | (reference only — see header) | Never forked | Base DTB stays at reference. No pristine binary copy in the overlay tracker; no source DTS fork in `bsp_sources/hardware/`. Carrier deltas live entirely in the DT overlay (next row). | | DT overlay skeleton (NEW) | Unconditional | Always | Create `/hardware/nvidia//nv-public/overlay/--+-.dts` (skeleton ‡); commit in `hardware/`, push to origin | | Per-dir Makefile registration | `/bsp_sources/hardware/nvidia//nv-public/overlay/Makefile` | Always | Append `dtbo-y += --+-.dtbo` after the **last literal-named** `dtbo-y +=` entry (BEFORE the `$(addprefix $(makefile-path)/,$(dtbo-y))` prefix block — inserting after `dtbo-y += $(old-dtbo)` silently drops the .dtbo). Same position-sensitive idiom and snippet as the composite slot's Makefile patch in [`../jetson-build-source/references/composite-registration.md#makefile-patch-idempotent-position-sensitive`](../jetson-build-source/references/composite-registration.md#makefile-patch-idempotent-position-sensitive). Commit in `hardware/`. Without this row, `nvidia-dtbs` never produces the `.dtbo` referenced by the next row's `OVERLAY_DTB_FILE+=` line and `flash.sh` aborts mid-flash on the missing file. | | Overlay wire-up | Unconditional | Always | Append `OVERLAY_DTB_FILE+=",--+-.dtbo"` to flash-conf fork (extra commit) | | nvpmodel config | `rootfs/etc/nvpmodel/nvpmodel__.conf` | Always | Filename: append `__` | | nvfancontrol config | `rootfs/etc/nvpower/nvfancontrol/nvfancontrol____.conf` | Always | Filename: substitute carrier portion (append `__` if source is module-keyed only) | | `nvpower.sh` patch | `rootfs/etc/systemd/nvpower.sh` | Always | Pristine + single customization commit with 4 insertions: (a) cvb cascade `elif [[ "${machine}" =~ "" ]]; then cvb=""` before reference; (b) inside module-SKU branch set `machine="---"`; (c) nvpmodel cascade branch for composite machine key → `conf_file=` nvpmodel fork; (d) cvb-keyed nvfancontrol cascade branch → `conf_file=` nvfancontrol fork | | BPMP DTB | prebuilt at `bootloader/generic/` (alt naming: no `p` prefix, `xxxx` SKU) | **Opt-in** y/N, default N — module-level, usually shared with reference | Fork binary: pristine + filename sub `--` → `--` (content unchanged). Extra commit on flash-conf fork rewriting `BPFDTB_FILE` to the renamed binary. | ¶ **`#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 `-` → `-`; 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 `__` (underscore-form) or `--` (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 = " carrier board"` and `compatible = "nvidia,-+-", "nvidia,"`. `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: ```text 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: ```yaml 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`](../../context/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. - **"`` not a symlink"** — NVIDIA convention is a `.conf` symlink to `--a.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](../../references/bsp-platforms-catalogue.md); update the catalogue rather than override in the profile. - **Commit message preview prompt blocks the run** — expected gate per [commit-batching](../../context/bsp-customization-workflow.md#commit-batching-in-the-overlay-tracker); 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.