aports: add fp6-charging-mode (offline charging, charger-boot detection)

Charger-insertion boots (androidboot.mode=charger, ABL-appended) divert to
a minimal charging.target instead of the full UI, ending the dead-battery
bootloop: ADSP charging/USB-PD runs, splash+panel killed ~6-10s in via an
initramfs hook, modem+cdsp stopped, radios/sensors suppressed, CPU capped.
Power key reboots to a normal boot, volume-up shows battery status,
volume-down enables USB ssh, unplug powers off. Measured >= breakeven on a
100mA-classified SDP port, strongly net-positive on real chargers.

Suspend duty-cycling (~13mA floor) exists behind an off-by-default flag:
resume from deep suspend intermittently kills the UFS link (hibern8 exit
failed ret=5) - do not enable until that kernel bug is fixed.

Byte-identical to the deployment verified on the dev phone 2026-08-24
(journal/power: r5 armed tests, crash autopsies, measurements).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

aports/device/fp6-charging-mode/charging-monitor.sh

@@ -0,0 +1,167 @@
+#!/bin/sh
+# Offline charging monitor (prototype r3). Runs only inside charging.target.
+#
+# - waits for the ADSP-backed battmgr supplies (charging + USB-PD live on
+#   the ADSP, which never sleeps — AP suspend does not touch the PD contract)
+# - blanks + powers down the display pipeline, stops modem/cdsp remoteprocs,
+#   caps CPU frequency, nudges UFS auto-hibernate
+# - unplug -> orderly poweroff (debounced ~6 s; a poweroff while plugged
+#   re-wakes via the USB_CHARGER PON trigger)
+# - power key -> logind reboots to a NORMAL boot (generator drop-in)
+# - suspend cycling (rock-bottom mode): only when /etc/charging-mode/
+#   enable-suspend exists AND ssh debug mode is off (/run/charging-mode-ssh,
+#   volume-down) AND the status display is off (/run/charging-mode-display,
+#   volume-up toggle). Arms an RTC wakealarm before every suspend and never
+#   suspends without a verified alarm.
+#
+# Deliberately NO rfkill anywhere: systemd-rfkill would persist a soft-block
+# into normal boots (the 2026-08-23 wifi trap).
+#
+# Failsafe: if battmgr never appears, reboot — that PONs as HARD_RESET, so
+# the phone comes back in a NORMAL boot and is never stuck dark.
+
+BAT=/sys/class/power_supply/qcom-battmgr-bat
+USB=/sys/class/power_supply/qcom-battmgr-usb
+WAKEALARM=/sys/class/rtc/rtc0/wakealarm
+SUSPEND_SECS=45
+
+log() { echo "charging-monitor: $*"; }
+
+log "offline charging mode active (prototype r5)"
+
+i=0
+while [ ! -r "$USB/online" ]; do
+    i=$((i + 1))
+    if [ "$i" -gt 180 ]; then
+        log "battmgr never appeared after ${i}s - failsafe reboot to normal boot"
+        exec systemctl reboot
+    fi
+    sleep 1
+done
+log "battmgr up after ${i}s"
+
+for b in /sys/class/backlight/*/brightness; do
+    [ -w "$b" ] && echo 0 > "$b" 2>/dev/null
+done
+log "panel blanked"
+
+# release the boot splash and power the display pipeline down (best effort —
+# brightness 0 alone leaves the DSI/DPU scanning out a black frame)
+if command -v plymouth >/dev/null 2>&1 && plymouth --ping 2>/dev/null; then
+    plymouth quit 2>/dev/null && log "plymouth quit"
+fi
+for f in /sys/class/graphics/fb*/blank; do
+    [ -w "$f" ] || continue
+    { echo 4 > "$f" || echo 1 > "$f"; } 2>/dev/null && log "fb powerdown via $f"
+done
+
+# radios/compute are pointless while charging — stop modem and cdsp
+# remoteprocs (adsp stays: it IS the charger; wpss left alone near the
+# WCN-combo trap). The stop write can block past a short timeout yet still
+# succeed — judge by the resulting state, not the write's exit code.
+for r in /sys/class/remoteproc/remoteproc*; do
+    name=$(cat "$r/name" 2>/dev/null)
+    case "$name" in
+    *mpss*|*modem*|*mss*|*cdsp*)
+        timeout 25 sh -c "echo stop > '$r/state'" 2>/dev/null
+        if [ "$(cat "$r/state" 2>/dev/null)" = "offline" ]; then
+            log "stopped remoteproc $name"
+        else
+            log "remoteproc $name did not stop (state=$(cat "$r/state" 2>/dev/null)) - continuing"
+        fi
+        ;;
+    esac
+done
+
+# cap CPU frequency to the minimum, then offline every core except cpu0
+# (a little @ 441.6 MHz) — emptying the two big clusters (cpu4-6, cpu7)
+# lets their cluster rails power-collapse entirely. Charging mode always
+# ends in a reboot, so no undo needed.
+for p in /sys/devices/system/cpu/cpufreq/policy*; do
+    cat "$p/cpuinfo_min_freq" > "$p/scaling_max_freq" 2>/dev/null
+done
+for c in /sys/devices/system/cpu/cpu[1-9]*; do
+    [ -w "$c/online" ] && echo 0 > "$c/online" 2>/dev/null
+done
+log "cpu freq capped to min, online cpus: $(cat /sys/devices/system/cpu/online 2>/dev/null)"
+# NOTE: do NOT touch UFS auto_hibern8 — the 2026-08-24 PD-boot crash
+# (ufshcd hibern8 exit failed, dead rootfs at t=34s) happened with our
+# auto_hibern8=5000 write + suspend-thrash; the write is the prime suspect
+# and its benefit was never measured.
+
+# battmgr power_supply events are wakeup sources, and a PPS charger streams
+# telemetry ~1/s — that turned suspend cycling into 1.2 s suspend-thrash on
+# the PD brick. Drop the psy wakeup flags: the RTC alarm is our only
+# intended waker (unplug is then detected at the next wake, <=45 s).
+for w in /sys/class/power_supply/qcom-battmgr-*/device/power/wakeup \
+         /sys/class/power_supply/qcom-battmgr-*/power/wakeup; do
+    [ -w "$w" ] && echo disabled > "$w" 2>/dev/null && log "wakeup disabled: $w"
+done
+
+suspend_enabled=false
+[ -e /etc/charging-mode/enable-suspend ] && suspend_enabled=true
+log "suspend cycling: $suspend_enabled (flag /etc/charging-mode/enable-suspend)"
+
+check_unplug() {
+    # debounced: three reads ~3 s apart must all say offline
+    n=0
+    while [ "$(cat "$USB/online" 2>/dev/null || echo 1)" = "0" ]; do
+        n=$((n + 1))
+        if [ "$n" -ge 3 ]; then
+            log "charger removed (capacity $(cat "$BAT/capacity" 2>/dev/null)%) - powering off"
+            exec systemctl poweroff
+        fi
+        sleep 3
+    done
+}
+
+sample() {
+    log "sample: cap $(cat "$BAT/capacity" 2>/dev/null)% status $(cat "$BAT/status" 2>/dev/null) bat $(cat "$BAT/current_now" 2>/dev/null)uA cc $(cat "$BAT/charge_counter" 2>/dev/null)uAh usb $(cat "$USB/voltage_now" 2>/dev/null)uV $(cat "$USB/current_now" 2>/dev/null)uA icl $(cat "$USB/input_current_limit" 2>/dev/null)uA online $(cat "$USB/online" 2>/dev/null)"
+}
+
+suspending() {
+    $suspend_enabled && [ ! -e /run/charging-mode-ssh ] && [ ! -e /run/charging-mode-display ]
+}
+
+tick=0
+thrash=0
+while :; do
+    check_unplug
+    # when suspend-cycling, log a full sample at EVERY wake — the persistent
+    # journal is the offline logger for charger tests where no ssh path
+    # exists (e.g. the PD brick occupying the USB port); in awake mode log
+    # once a minute
+    if suspending || [ $((tick % 12)) -eq 0 ]; then
+        sample
+    fi
+    tick=$((tick + 1))
+
+    if suspending && [ -w "$WAKEALARM" ]; then
+        echo 0 > "$WAKEALARM" 2>/dev/null
+        echo "+$SUSPEND_SECS" > "$WAKEALARM" 2>/dev/null
+        if [ -n "$(cat "$WAKEALARM" 2>/dev/null)" ]; then
+            t0=$(date +%s)
+            echo mem > /sys/power/state 2>/dev/null || { log "suspend write failed - falling back to sleep"; sleep 30; }
+            dur=$(( $(date +%s) - t0 ))
+            log "slept ${dur}s"
+            # thrash guard: instant resumes back-to-back nearly killed UFS
+            # on the PD brick (2026-08-24) — three short cycles in a row
+            # means something wakes us constantly; stop suspending and stay
+            # in awake mode (still fine: any real charger out-supplies it)
+            if [ "$dur" -lt 10 ]; then
+                thrash=$((thrash + 1))
+                if [ "$thrash" -ge 3 ]; then
+                    log "suspend thrash (3 consecutive <10s cycles) - disabling suspend cycling this session"
+                    suspend_enabled=false
+                fi
+            else
+                thrash=0
+            fi
+        else
+            log "could not arm RTC wakealarm - NOT suspending (sleep fallback)"
+            sleep 30
+        fi
+    else
+        sleep 5
+    fi
+done