From 24f073d4009e4a35091c676aff83c03dac5c1a6b Mon Sep 17 00:00:00 2001
From: Simon Glass <sjg@chromium.org>
Date: Thu, 16 Dec 2021 20:59:37 -0700
Subject: fdt: Makefile: Ensure that OF_BOARD is used when needed

Boards which define OF_HAS_PRIOR_STAGE must define OF_BOARD at present,
since a custom function is the only way to obtain the devicetree at
runtime.

Add a build error when this requirement is not met, to avoid accepting
any patches which break this requirement.

Add an allowlist for boards which use it, currently none. This allowlist
can be updated for local development, if needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: change of_whitelist to of_allowlist]
Signed-off-by: Tom Rini <trini@konsulko.com>
---
 Makefile                 |  7 +++++++
 scripts/check-of.sh      | 42 ++++++++++++++++++++++++++++++++++++++++++
 scripts/of_allowlist.txt |  1 +
 3 files changed, 50 insertions(+)
 create mode 100755 scripts/check-of.sh
 create mode 100644 scripts/of_allowlist.txt

diff --git a/Makefile b/Makefile
index 633e038ffa..a4f267c2db 100644
--- a/Makefile
+++ b/Makefile
@@ -1053,6 +1053,10 @@ quiet_cmd_cfgcheck = CFGCHK  $2
 cmd_cfgcheck = $(srctree)/scripts/check-config.sh $2 \
 		$(srctree)/scripts/config_whitelist.txt $(srctree)
 
+quiet_cmd_ofcheck = OFCHK   $2
+cmd_ofcheck = $(srctree)/scripts/check-of.sh $2 \
+		$(srctree)/scripts/of_allowlist.txt
+
 # Concat the value of all the CONFIGs (result is 'y' or 'yy', etc. )
 got = $(foreach cfg,$(1),$($(cfg)))
 
@@ -1127,6 +1131,9 @@ endif
 	@# know about unless they are in Kconfig. All the existing CONFIG
 	@# options are whitelisted, so new ones should not be added.
 	$(call cmd,cfgcheck,u-boot.cfg)
+	@# Check that this build does not override OF_HAS_PRIOR_STAGE by
+	@# disabling OF_BOARD.
+	$(call cmd,ofcheck,$(KCONFIG_CONFIG))
 
 PHONY += dtbs
 dtbs: dts/dt.dtb
diff --git a/scripts/check-of.sh b/scripts/check-of.sh
new file mode 100755
index 0000000000..0f0bf51664
--- /dev/null
+++ b/scripts/check-of.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+# Copyright 2021 Google LLC
+# Written by Simon Glass <sjg@chromium.org>
+#
+# Check that the .config file provided does not try to disable OF_BOARD for
+# boards that use CONFIG_OF_HAS_PRIOR_STAGE
+#
+# Usage
+#    check-of.sh <path to .config> <path to allowlist file>
+#
+# For example:
+#   scripts/check-of.sh b/chromebook_link/u-boot.cfg kconfig_allowlist.txt
+#
+# Exit code is 0 if OK, 3 if the .config is wrong, as above
+
+set -e
+set -u
+
+PROG_NAME="${0##*/}"
+
+usage() {
+	echo "$PROG_NAME <path to .config> <path to allowlist file>"
+	exit 1
+}
+
+[ $# -ge 2 ] || usage
+
+path="$1"
+allowlist="$2"
+
+sys_config="$(sed -n 's/CONFIG_SYS_CONFIG_NAME="\(.*\)"$/\1/p' "${path}")"
+
+if grep -q OF_HAS_PRIOR_STAGE=y "${path}"; then
+	if ! grep -lq CONFIG_OF_BOARD=y "${path}"; then
+		echo >&2 "This board uses a prior stage to provide the device tree."
+		echo >&2 "Please enable CONFIG_OF_BOARD to ensure that it works correctly."
+		if grep -q "${sys_config}" "${allowlist}"; then
+			exit 0
+		fi
+		exit 3
+	fi
+fi
diff --git a/scripts/of_allowlist.txt b/scripts/of_allowlist.txt
new file mode 100644
index 0000000000..e82cf557bb
--- /dev/null
+++ b/scripts/of_allowlist.txt
@@ -0,0 +1 @@
+# List of boards which are permitted to use OF_HAS_PRIOR_STAGE without OF_BOARD
-- 
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