BFE Engineering
42fb386f60
Replace every em dash with real punctuation (rewrites, not hyphen swaps) in docs, code comments, scripts, configs, and the port records; convert en dashes, curly quotes, ellipsis glyphs, arrows, and section signs to ASCII; drop machine-writing tell phrases from living docs. ADR titles now use a colon. The M2 bring-up DTS model string carried an em dash into the patch series and its record echoes; fixed at both, and the full series re-verified to apply cleanly onto pristine 6.18.46. One comment in freshness.h deliberately names the em dash glyph the UI renders as the unknown mark; that is data, kept as prose naming it. Verified: cargo tests (sim, config-lint, rs485-bridge), shellcheck, both driver MC/DC harnesses, patches-apply.
45 lines
2.6 KiB
Markdown
45 lines
2.6 KiB
Markdown
# AIC8800 wifi: VERIFIED on warden-c8a3 (self-built 6.18.46), 2026-08-25
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**Result: wifi works end-to-end on our self-built Linux 6.18.46.** Modules built
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from the ported source (vermagic `6.18.46 SMP mod_unload ARMv7 p2v8`), loaded on
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the panel, downloaded firmware to the AIC8800DC, created `wlan0`, and completed a
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live RF scan.
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## Evidence (serial console, _b slot = our 6.18 kernel)
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- `insmod aic8800_bsp.ko` -> firmware download OK: `aicwf_patch_config_8800dc done`,
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`Start app: 00120000`, BSP_RC=0.
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- `insmod aic8800_fdrv.ko` -> `ieee80211 phy0: HT supp 1, VHT supp 1, HE supp 1`,
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FDRV_RC=0.
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- `wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> ... link/ether <device MAC>`
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- `iw dev wlan0 scan` found real APs (SSIDs/BSSIDs redacted for publication):
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- **the site AP at 2412 MHz, -43 dBm**
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- a neighboring guest AP at 2412 MHz, -73 dBm
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- +several more, correct signal strengths -> RF path fully functional.
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## Why MODULES, not built-in (=y)
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Built-in device_initcalls run BEFORE the dw_mmc/SDIO controller probes. Initcalls
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are sequential: `aicbsp_init` blocked 3.3-7.5 s doing the eager chip bring-up, and
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the mmc controller only probed at 7.9 s (SDIO card at 8.2 s), AFTER aicbsp had
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already given up (`aicsdio.c:597` 2 s `down_timeout` -> `sdio_unregister_driver`).
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Extending the timeout can't help (aicbsp blocks the very mmc probe that would
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enumerate the card, a deadlock). Loaded as modules AFTER boot (mmc up, card at
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4 s), `insmod aic8800_bsp` registers the SDIO driver against an already-present
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card -> probe fires immediately -> firmware download -> fdrv -> wlan0. This is the
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vendor-proven flow.
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## Kernel-size fix (needed to boot the wifi kernel at all)
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The wifi kernel grew the gzip zImage to 12.12 MB; rockchip U-Boot loads the kernel
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blob at 0x8000 and relocates the DTB to 0xc00000 (12 MB), so a >~11.95 MB zImage
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overruns the FDT at U-Boot load time (`Sysmem Error: KERNEL overlap with FDT`) and
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FLARE-AB falls back to _a. Switched `CONFIG_KERNEL_GZIP` -> `CONFIG_KERNEL_XZ`:
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zImage 12.12 MB -> 8.15 MB (module build), ~4 MB headroom under the FDT. Also the
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right call for a firmware kernel. (Uncompressed Image is ~30 MB; the ARM
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decompressor relocates the FDT at runtime, so only the U-Boot LOAD-time overlap
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mattered: proven by the kernel booting once the zImage fit.)
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## Boot-time auto-load (follow-up, deployment layer, not the kernel port)
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Modules were insmod'd manually for this verify. Production auto-load needs a
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loader that inserts `aic8800_bsp.ko` -> `aic8800_fdrv.ko` (-> `aic8800_btlpm.ko`) in
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order from wherever they're staged; the vendor `insmod_wifi.sh` references a
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different variant (`aic_load_fw.ko`/`bcmdhd.ko`, absent here). Track in the rootfs.
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