Initial: BESser umbrella for BES2600 driver mainlining

Sets up the BES2600 mainlining work tree with:

- README: project overview, hardware target, driver lineage
  (CW1200 -> Bestechnic -> arjan-vlek -> Mobian/danctnix), patch series
  status, repo map, build/deploy workflow.

- patches/: c1 patch generated by git format-patch from
  marfrit/bes2600-dkms branch bes2600/factory-request-firmware
  (checkpatch.pl --no-tree --strict: 0 errors / 0 warnings / 0 checks).

- scripts/: build-bes2600-on-ohm.sh, deploy-c1-to-ohm.sh,
  backup-ohm-kernel.sh - reproducible build + deploy + backup.

- fw-analysis/: per-blob strings.txt + fnnames.txt extracted from the
  4 firmware blobs pulled from ohm 2026-04-21. Source binaries NOT
  committed (Bestechnic-proprietary).

- notes/: observed-bugs.md (4 known bug surfaces with file:line +
  patch-series cross-reference), source-map.md (every public driver
  source variant + their canonical role).

Companion work tree: marfrit/bes2600-dkms (Mobian DKMS fork) at
git.reauktion.de.

Signed-off-by: Markus Fritsche <fritsche.markus@gmail.com>

scripts/backup-ohm-kernel.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+# Snapshot kernel + modules + bes2600 firmware from ohm into ~/backup/.
+#
+# Per feedback_backup_before_replace.md: always backup before replacing
+# kernel/modules/configs, with versioned labels.
+
+set -e
+
+TS=$(date +%Y%m%d-%H%M%S)
+KVER=$(uname -r)
+DEST=/home/mfritsche/backup
+mkdir -p ${DEST}
+
+OUT=${DEST}/ohm-kernel-${KVER}-${TS}.tar.zst
+
+echo "=== Sizes ==="
+sudo du -sh /boot /lib/modules/${KVER} /lib/firmware/bes2600
+
+echo "=== Tar ==="
+sudo tar --use-compress-program='zstd -3' \
+    -cf "${OUT}" \
+    -C / boot lib/modules/${KVER} lib/firmware/bes2600
+sudo chown $(id -un):$(id -gn) "${OUT}"
+
+echo "=== Result ==="
+ls -lah "${OUT}"
+zstd -t "${OUT}" 2>&1 | tail -1

scripts/build-bes2600-on-ohm.sh

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+#!/bin/bash
+# Native aarch64 build of bes2600 driver on ohm.
+#
+# Requires linux-pinetab2-headers package installed:
+#   sudo pacman -S --noconfirm linux-pinetab2-headers
+#
+# Source tree expected at /home/mfritsche/bes2600-build/ — populate via:
+#   tar -C ~/src/besser/linux-pinetab2/drivers/staging/bes2600 -cf - . | \
+#     ssh mfritsche@ohm.vpn 'mkdir -p ~/bes2600-build && tar -C ~/bes2600-build -xf -'
+#
+# (Mobian DKMS layout works too if you point at the bes2600/ subdir.)
+
+set -e
+
+cd /home/mfritsche/bes2600-build || { echo "no source tree at /home/mfritsche/bes2600-build"; exit 1; }
+[ -f Makefile ] || { echo "no Makefile in source tree"; exit 1; }
+
+# Clean stale root-owned files (in case sudo-make left some)
+sudo -n chown -R mfritsche:mfritsche . 2>/dev/null || true
+make clean
+
+# Native parallel build (4 cores on ohm)
+make -j4
+
+# Strip to manageable size + report
+strip --strip-debug bes2600.ko -o bes2600.stripped.ko
+ls -lh *.ko
+modinfo bes2600.stripped.ko | grep -E 'srcversion|vermagic'

scripts/deploy-c1-to-ohm.sh

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+#!/bin/bash
+# Deploy a built bes2600 module to /lib/modules/<ver>/extra/ on ohm.
+#
+# This is the SAFE deploy path: no live module reload (which can wedge
+# the chip per Pine64 known issues), just persistent install + reboot.
+#
+# Run on ohm. Modules expected built at /home/mfritsche/bes2600-build/.
+
+set -e
+
+KVER=$(uname -r)
+EXTRA=/lib/modules/${KVER}/extra
+STAGING=/lib/modules/${KVER}/kernel/drivers/staging/bes2600
+
+cd /home/mfritsche/bes2600-build
+[ -f bes2600.stripped.ko ] || [ -f bes2600.ko ] || { echo "no bes2600.ko built"; exit 1; }
+
+NEW=$( [ -f bes2600.stripped.ko ] && echo bes2600.stripped.ko || echo bes2600.ko )
+
+echo "=== Backup originals (idempotent) ==="
+sudo cp -np ${STAGING}/bes2600.ko.zst ${STAGING}/bes2600.ko.zst.pre-deploy.bak 2>&1 || true
+sudo cp -np ${STAGING}/bes2600_btuart.ko.zst ${STAGING}/bes2600_btuart.ko.zst.pre-deploy.bak 2>&1 || true
+ls -la ${STAGING}/
+
+echo "=== Install patched modules to /extra/ ==="
+sudo install -D -m644 ${NEW} ${EXTRA}/bes2600.ko
+[ -f bes2600_btuart.ko ] && sudo install -D -m644 bes2600_btuart.ko ${EXTRA}/bes2600_btuart.ko
+sudo depmod -a
+ls -la ${EXTRA}/
+
+echo "=== Verify modprobe will pick our build ==="
+modinfo bes2600 | grep -E 'filename|srcversion'
+modinfo bes2600_btuart | grep -E 'filename|srcversion'
+
+echo
+echo "Deploy complete. Reboot to load the new module:"
+echo "  sudo reboot"
+echo
+echo "Rollback if anything breaks:"
+echo "  sudo rm ${EXTRA}/bes2600*.ko && sudo depmod -a && sudo reboot"