imx95-pqc-demo: switch the boot chain from the board itself, and say how at the end of the demo

imx95-pqc-demo/demo/demo-uart.sh

@@ -252,4 +252,11 @@ echo " Demo complete. Both cores booted firmware verified with ML-DSA-87:"
 echo "   Cortex-A55  wolfBoot -> Linux    (above, before this stream)"
 echo "   Cortex-M7   wolfBoot -> Zephyr   [M7 ]"
 echo " Power-cycle the board to run it again."
+echo
+# Printed here because the serial console is the only input at a show, and
+# this is the last thing on it.
+echo " Switch the boot chain, then power-cycle:"
+echo "   sudo ~/switch-boot.sh 0      # stock U-Boot chain"
+echo "   sudo ~/switch-boot.sh 1      # wolfBoot chain"
+echo "   sudo ~/switch-boot.sh --show # which one is selected now"
 echo "=================================================================="

imx95-pqc-demo/demo/switch-boot.sh

@@ -0,0 +1,69 @@
+#!/usr/bin/env bash
+# Switch the board between the stock U-Boot chain and the wolfBoot chain.
+# Runs ON THE BOARD, so it needs no host, no network and no ssh:
+#
+#   sudo bash ~/demo/switch-boot.sh          # flip to the other chain
+#   sudo bash ~/demo/switch-boot.sh 0        # force stock U-Boot (boot0)
+#   sudo bash ~/demo/switch-boot.sh 1        # force wolfBoot (boot1)
+#   sudo bash ~/demo/switch-boot.sh --show   # report only, change nothing
+#
+# The i.MX95 boot ROM takes its AHAB container set from whichever eMMC boot
+# partition EXT_CSD selects, so this is an EXT_CSD write plus a reboot. Both
+# chains share the eMMC rootfs, so this script is present either way and the
+# switch works in both directions.
+set -uo pipefail
+
+MMC=/dev/mmcblk0
+# PARTITION_CONFIG bits [5:3]: 1 = boot0, 2 = boot1. mmc-utils uses the same
+# numbering for "mmc bootpart enable".
+name_of() { case "$1" in 1) echo "boot0 (stock U-Boot chain)" ;; 2) echo "boot1 (wolfBoot chain)" ;; *) echo "unknown ($1)" ;; esac; }
+
+if [ "$(id -u)" != "0" ]; then
+    echo "needs root: sudo bash $0 $*" >&2
+    exit 1
+fi
+
+current() {
+    local v
+    v=$(mmc extcsd read $MMC 2>/dev/null \
+        | grep -i "PARTITION_CONFIG" | grep -o "0x[0-9a-fA-F]*" | head -1)
+    [ -n "$v" ] || return 1
+    echo $(( (v >> 3) & 7 ))
+}
+
+CUR=$(current) || { echo "cannot read PARTITION_CONFIG" >&2; exit 1; }
+echo "current: $(name_of "$CUR")"
+
+case "${1:-}" in
+    --show|-s) exit 0 ;;
+    0) NEW=1 ;;
+    1) NEW=2 ;;
+    "") NEW=$(( CUR == 1 ? 2 : 1 )) ;;
+    *)  echo "usage: $0 [0|1|--show]" >&2; exit 1 ;;
+esac
+
+if [ "$NEW" = "$CUR" ]; then
+    echo "already on $(name_of "$CUR") - nothing to do"
+    exit 0
+fi
+
+# Refuse to switch into a partition with no container. The ROM would find
+# nothing to boot, and recovering from that needs the B4 button and uuu.
+DEV=/dev/mmcblk0boot$(( NEW - 1 ))
+TAG=$(dd if=$DEV bs=1 skip=32771 count=1 2>/dev/null | od -An -tx1 | tr -d ' \n')
+if [ "$TAG" != "87" ]; then
+    echo "$DEV has no AHAB container at 0x8000 (tag 0x$TAG) - refusing" >&2
+    exit 1
+fi
+
+echo "switching to: $(name_of "$NEW")"
+mmc bootpart enable "$NEW" 1 $MMC || { echo "mmc bootpart failed" >&2; exit 1; }
+AFTER=$(current)
+if [ "$AFTER" != "$NEW" ]; then
+    echo "PARTITION_CONFIG did not take (still $(name_of "$AFTER"))" >&2
+    exit 1
+fi
+sync
+echo "now set to: $(name_of "$AFTER")"
+echo
+echo "Power-cycle the board to boot it. Run this again to switch back."

imx95-pqc-demo/demo/whichbutton.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+"""Print any button/switch event from the carrier. No root needed (group input).
+Run on the board, press every button you can find, Ctrl-C when done."""
+import struct, sys, select
+FMT = 'llHHi'; SZ = struct.calcsize(FMT)
+TYPES = {1: 'KEY', 5: 'SWITCH'}
+devs = {}
+for n in (0, 1):
+    try:
+        devs[open(f'/dev/input/event{n}', 'rb', buffering=0)] = f'event{n}'
+    except OSError as e:
+        print(f'event{n}: {e}')
+if not devs:
+    sys.exit('no readable input devices')
+print('watching:', ', '.join(devs.values()), '- press buttons now')
+try:
+    while True:
+        r, _, _ = select.select(list(devs), [], [], 60)
+        if not r:
+            print('(60s with no events)')
+            continue
+        for f in r:
+            sec, usec, typ, code, val = struct.unpack(FMT, f.read(SZ))
+            if typ in TYPES:
+                print(f'  {devs[f]}  {TYPES[typ]} code={code} value={val}'
+                      f'  {"PRESS" if val else "release"}')
+except KeyboardInterrupt:
+    print('\ndone')