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241 lines
13 KiB
Markdown
241 lines
13 KiB
Markdown
# Building ForgeFIRM with kas
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The **forgefirm** repo is the base of the project: it controls the build,
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the resulting firmware images land here, and all build/install docs live here.
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It uses [**kas**](https://kas.readthedocs.io/) to manage Yocto layers and drive
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the build.
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## Baseline
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|---|---|
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| Yocto release | **Scarthgap 5.0 LTS** |
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| Kernel | **linux-fslc 6.12** (mainline LTS, from meta-freescale) |
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| Machine | `glowforge` (i.MX6 Solo SOM — Basic/Plus/Pro) |
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| Distro | `forgefirm` |
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| Image | `forgefirm-image` |
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## Layout
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```
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openglow-forgefirm/
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├── forgefirm/ ← THIS repo, the base
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│ ├── kas/
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│ │ ├── forgefirm-glowforge.yml ← build entry point
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│ │ └── README.md ← this file
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│ ├── meta-forgefirm/ ← the forgefirm layer (this repo)
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│ ├── BUILD.md / INSTALL.md / SERIAL.md
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│ ├── layers/ ← kas-cloned upstreams (gitignored)
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│ ├── build/ ← bitbake output incl. images (gitignored)
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│ ├── downloads/ sstate-cache/ ← caches (gitignored)
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│ └── .gitignore
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└── meta-openglow/ ← Glowforge BSP layers (local sibling checkout)
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```
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`meta-openglow` is referenced as a **local sibling** (`../meta-openglow`), so
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its in-place edits are what gets built. The commented pinned-remote block in
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`forgefirm-glowforge.yml` makes the forgefirm repo fully self-contained when
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flipped on. The source repos the recipes build (`kernel-module-glowforge`,
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`grblHAL-glowforge`, `forgectrl`, `python3-gfhardware`, `Glowforge-Utilities`)
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are fetched by pinned `SRCREV` and are not needed as local checkouts.
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## Prerequisites
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A Linux build host, or **WSL2** on Windows (officially supported by Yocto).
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> **WSL2 note:** keep this whole tree on the WSL2 *native* ext4 filesystem
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> (e.g. `~/dev/openglow-forgefirm`), **not** under `/mnt/c/...`. The Windows
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> mount breaks case-sensitivity/permissions and is very slow for Yocto. Give the
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> WSL2 VM plenty of RAM and disk in `.wslconfig`.
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```bash
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pipx install kas # or: pip install kas
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```
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## Build
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Run from the **forgefirm repo root** so outputs land inside it:
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```bash
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cd forgefirm
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kas build kas/forgefirm-glowforge.yml # fetch layers + full build
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kas shell kas/forgefirm-glowforge.yml # interactive bitbake environment
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kas dump kas/forgefirm-glowforge.yml # print the resolved config
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```
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The bootable image lands in `build/tmp/deploy/images/glowforge/`. Flashing /
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dual-boot install steps are in [`../INSTALL.md`](../INSTALL.md).
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### Container build (optional, reproducible host)
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```bash
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cd forgefirm
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kas-container build kas/forgefirm-glowforge.yml
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```
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## Pinning exact versions (reproducible builds)
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The config tracks the `scarthgap` **branch** of each upstream layer. To lock
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every layer to an exact commit:
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```bash
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kas lock kas/forgefirm-glowforge.yml # writes kas/forgefirm-glowforge.lock.yml
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```
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kas auto-loads the lockfile on subsequent runs. Commit it; refresh deliberately.
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## Push & release order (source-of-truth sequencing)
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The build is only reproducible when recipe pins, layer branches, and the kas
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config move in the right order. The sequence, with current status:
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1. **Source repos pushed & pinned** — **DONE.** Every source repo
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(`kernel-module-glowforge`, `python3-gfhardware`, `Glowforge-Utilities`,
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`grblHAL-glowforge`, `forgectrl`) is on GitHub and its recipe pins an exact
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`SRCREV` — no `AUTOREV` anywhere. Whenever a source repo changes: push it,
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then bump the recipe `SRCREV` deliberately (BSP recipes in meta-openglow,
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ForgeFIRM components in meta-forgefirm) and re-verify with
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`bitbake -c fetch <recipe>`.
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2. **meta-openglow pushed** — **DONE.** The Scarthgap port lives on
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the **`scarthgap` branch** (Yocto layer convention; the Dunfell-era `master`
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is untouched). Development continues on the local sibling checkout; push /
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fast-forward `scarthgap` as work lands.
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3. **forgefirm pushed** with the kas config and a `kas lock` lockfile pinning
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the upstream layers (poky, meta-openembedded, meta-freescale,
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meta-freescale-distro).
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4. **At release time**:
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- flip `meta-openglow` in `forgefirm-glowforge.yml` from the local-sibling
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block to the pinned-remote block (commented FUTURE block in the file);
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- refresh `kas lock`, tag all repos, and prove self-containment by building
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from a **fresh clone**.
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5. **GitHub release**: run `scripts/release.sh <version>` on the build
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host. It gates (version single-source, rootfs-vs-slot size,
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installer-embedded pubkey vs the signing key, factory-era fwup
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verification), builds, packs and signs `forgefirm.fw`, stages the
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assets with `sha256sums.txt`, and prints the `gh release create`
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command. Assets and their exact names (the installer and the update
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manager download them verbatim): `forgefirm.fw`, `sha256sums.txt`,
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`forgefirm-image-glowforge.rootfs.wic.gz`. The release tag
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`v<version>` = `FORGEFIRM_RELEASE` = the rootfs `/etc/forgefirm-version`
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= the `.fw` meta-version; `release.sh` enforces the agreement.
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All recipes fetch their pinned revision from GitHub, so an image build is
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reproducible from the repos alone. For fast iteration on a source repo, bump
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its pin per iteration, or add a **local, untracked** `externalsrc` bbappend
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pointing at a working checkout — never commit one, or released images stop
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matching the pins.
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## Scarthgap migration backlog
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The kas scaffold + `LAYERSERIES_COMPAT` bumps let the layers be *selected* under
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Scarthgap, but the legacy (Dunfell/Gatesgarth) layers won't build clean until:
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1. ~~**Override-syntax migration**~~ — **DONE.** All `_append`/`_prepend`/
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`_remove`/`_${PN}` override syntax converted to the colon form across
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`meta-forgefirm`, `meta-openglow-core`, and `meta-glowforge-bsp` (22
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occurrences).
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2. **Kernel forward-port (4.14 → linux-fslc 6.12.20)** — the factory NXP vendor
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kernel (linux-imx 4.14.98) carried 7 out-of-tree changes; these are re-derived
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against mainline 6.12 in `meta-glowforge-bsp/recipes-kernel/linux/linux-fslc_%.bbappend`
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(the forward-port landing zone), **not** re-applied as the 4.14 patches.
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- **Foundation — DONE.** `linux-fslc` 6.12.20 builds for `glowforge` with a
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ported device tree (`glowforge.dts` + `openglow_common.dtsi` overlaid into
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`arch/arm/boot/dts/nxp/imx/`, registered via a Makefile patch) and deploys
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`zImage` + `glowforge.dtb`. Boot-core + mainline-bound peripherals only.
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- **Free wins — DONE.** bus-freq disable *dropped* (no mainline busfreq);
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`st,lis2hh12` ×3 + `national,lm75b` + `ti,wl1805` + gpio keys/leds bind to
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mainline drivers; `reg-userspace-consumer` enabled via `glowforge.cfg`.
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(SPI-delay / PWM-prescaler dispositions are under Motion polish below.)
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- **Motion path — DONE and hardware-validated** (live-fed pulse stream,
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real gantry motion, laser fire). The whole chain forward-ports and
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compiles on 6.12:
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- **EPIT API**: `epit_api.c` in `arch/arm/mach-imx` (`CONFIG_MXC_EPIT_API`),
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in vmlinux, symbols exported; `&epit1/&epit2` in the DT.
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- **SDMA-expose**: re-created `dma-imx-sdma.h` + `0003-imx-sdma-*.patch`
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(un-static survivors, re-added the glowforge helpers, custom int-callback
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hook); expose symbols in `Module.symvers`.
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- **`glowforge.ko`**: ported across many 6.12 API changes
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(`tasklet_hrtimer`→soft hrtimer, `timer_setup`, LED-trigger API,
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`pwm_get`, `spi_delay`/`controller`, `filelock.h`, void `.remove`,
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1-arg i2c probe). Compiles + links, 0 undefined symbols; the recipe
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fetches the module by pinned `SRCREV`.
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- **DT**: `glowforge,cnc/thermal/pic/head` re-added with `pwms`/`pwm-names`
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phandles; `glowforge.dtb` compiles with all motion nodes.
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Motion polish: PWM prescaler (factory 1001) is **obsolete** — 6.12
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`pwm-imx27` auto-computes the prescaler from the requested period. The PIC
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inter-word SPI delay (factory 1005) is a **hardware-bring-up TODO**: 6.12
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`spi-imx.c` has no `PERIODREG`/`word_delay` programming, so re-derive it in
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`spi_imx_setupxfer` (write `MX51_ECSPI_PERIODREG` from `t->word_delay`,
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guarded to ECSPI) and verify the wait-states on a scope. pic.c keeps the
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inter-transfer delay meanwhile. The factory `glowforge,imx-pwm-audio`
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(buzzer) driver is not part of ForgeFIRM.
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- **Camera — DONE and hardware-validated.** The factory
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`ov5648_mipi.c` (NXP's removed `v4l2_int_device`/`mxc_v4l2_capture`) is
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replaced by the mainline `ovti,ov5648` subdev + imx6 `imx-media` (IPU CSI)
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+ `imx6-mipi-csi2` receiver. The factory CAM_SEL MIPI switch is modeled
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with the mainline `video-mux` (gpio-mux on `gpio7 10`): both sensors →
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video-mux → `mipi_csi` → IPU CSI. Sensor `xvclk` is the board's 24 MHz
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fixed oscillator (matching the factory DTB); avdd/dovdd/dvdd rails are in
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the DT. Both cameras stream live through forgectrl (MJPEG at 15 fps with
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VPU JPEG encode, full-resolution snapshots, mux arbitration).
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**HD-unit caveat:** the DT lists both `ovti,ov5648` (5 MP) and
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`ovti,ov8856` (8 MP) at 0x36 so one image covers both, and the driver
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matching the chip ID wins — but mainline `ov8856` expects a 19.2 MHz
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xvclk and only warns at 24 MHz, and the capture path is written to
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ov5648's SBGGR8 2592×1944 format set. 8 MP "HD" modules therefore bind
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but do not capture; adding 24 MHz PLL modes plus a sensor-aware capture
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path is the open work.
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3. **u-boot** — **DONE.** The `glowforge` u-boot is
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a standalone `u-boot_2020.01.bb` (Scarthgap's poky has no u-boot 2020.01
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base recipe to extend). It reuses poky's
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`u-boot-common.inc`/`u-boot.inc`, pins `SRCREV` to the upstream **v2020.01**
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tag with the matching `Licenses/README` md5, and overlays the glowforge board
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support + arch-Kconfig patch. **Builds clean under Scarthgap (GCC 13, no
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source fixes) and deploys `u-boot-glowforge.imx`.** Remaining: move
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`fw_printenv`/`fw_setenv` from `u-boot-fw-utils` to `libubootenv`
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(`PREFERRED_PROVIDER_u-boot-fw-utils` in `glowforge.inc`) when the rootfs needs
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them.
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4. **Device tree — DONE.** The `glowforge` `.dts` is validated against the
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linux-fslc 6.12 bindings and against the running board (motion, safety
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readbacks, cameras, sensors all bind and work).
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5. **Real-time strategy — decided.** The kernel runs
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`CONFIG_PREEMPT=y` (factory behavior; `imx_v6_v7_defconfig` alone gives only
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`PREEMPT_VOLUNTARY`). **PREEMPT_RT is not selectable on arm32 6.12** (no
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`ARCH_SUPPORTS_RT`) and is **not needed for the pulse feeder**. The
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argument is about queue depth, not ring size: the ring drains at 1 byte
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per EPIT tick (≤200 KB/s even at the 200 kHz ceiling), so the live
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feeder's bounded queue depth of ~150 ms — a few KB in flight — already
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rides out worst-case scheduling latency with orders of magnitude to spare
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(measured: 0.2 ms worst write latency under full CPU + I/O load; the
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underrun bench ran 100 kHz for 120 s with zero underruns). The ring
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itself is 16 MiB (the `ring_mb` module parameter, backed by the 16 MiB
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reserved pool): ~84 s of stream at 200 kHz, ~28 min at the 10 kHz
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cloud-mode tick — a capacity that matters for the whole-job preload of
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cloud mode, not for latency. Bounded queue depth + `SCHED_FIFO` for the
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feeder is the design; revisit RT only if the underrun bench ever
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contradicts this arithmetic.
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6. **gfui-client → forgectrl — DONE.** The stock `gfui-client` is excluded
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from `forgefirm-image` (`IMAGE_INSTALL:remove = "gfui-client"` in
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`meta-forgefirm/recipes-forgefirm/images/forgefirm-image.bb`). Its slot is
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filled by `forgectrl` (github.com/ScottW514/forgectrl — the machine-services
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daemon: web control panel, cameras, telemetry, settings, diagnostics,
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cooling engine, updates, and controller-mode supervision) plus the two
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controllers it supervises, `grblhal-glowforge` (Grbl over TCP:23) and
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`gfcloud` (the optional Glowforge web-service client, off unless selected).
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---
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**Image status:** `forgefirm-image` **builds end-to-end** on the forward-ported
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stack and deploys `forgefirm-image-glowforge.rootfs.wic.gz` (+ `zImage`,
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`glowforge.dtb`, `u-boot-glowforge.imx`) under `build/tmp/deploy/images/glowforge/`.
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Build-time prerequisites baked into the config: `ACCEPT_FSL_EULA = "1"` (NXP
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firmware-imx — the image also installs `firmware-imx-lic` so the EULA text
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ships beside the blobs) and the kernel default in `glowforge.conf`. Every
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`LICENSE` string in the layers (`meta-forgefirm`, `meta-glowforge-bsp`,
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`meta-openglow-core`) is SPDX, and the recipes for third-party components
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that carry more than one license (`wlconf`, `python3-gfhardware`) declare
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each of them with a checksum on its license text. The stack
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is hardware-validated end to end: motion timing, the laser and safety chain,
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the camera pipeline, both controller modes, and the A/B install path.
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