Merge branch '2021-12-23-make-OF_BOARD-a-boolean' into next

Merge v8 of Simon's series to make CONFIG_OF_BOARD a boolean option.
Quoting him:

With Ilias' efforts we have dropped OF_PRIOR_STAGE and OF_HOSTFILE so
there are only three ways to obtain a devicetree:

   - OF_SEPARATE - the normal way, where the devicetree is built and
      appended to U-Boot
   - OF_EMBED - for development purposes, the devicetree is embedded in
      the ELF file (also used for EFI)
   - OF_BOARD - the board figures it out on its own

The last one is currently set up so that no devicetree is needed at all
in the U-Boot tree. Most boards do provide one, but some don't. Some
don't even provide instructions on how to boot on the board.

The problems with this approach were covered in another patch[1], since
removed from this series.

In practice, OF_BOARD is not really distinct from OF_SEPARATE. Any board
can obtain its devicetree at runtime, even it is has a devicetree built
in U-Boot. This is because U-Boot may be a second-stage bootloader and its
caller may have a better idea about the hardware available in the machine.
This is the case with a few QEMU boards, for example.

So it makes no sense to have OF_BOARD as a 'choice'. It should be an
option, available with either OF_SEPARATE or OF_EMBED. This would allow
rpi3, for example, to run with the devicetree provided by the prior
bootloader.

This series makes this change, adding various missing devicetree files
(and placeholders) to make the build work.

To make the 'prior stage' side of things more deterministic, a new
OF_HAS_PRIOR_STAGE is added, which cannot be disabled by updated a board's
defconfig. This should help to prevent mistakes.

It also adds a run-time message showing where the devicetree came from,
as well as warnings if the board's expected flow is not being used. This
comes originally from the 'standard passage' series, which depends on
this series.

It also provides a few qemu clean-ups discovered along the way. The
qemu-riscv64_spl problem is fixed.

Please see [2] for discussion on the v6 series.

I put Heinrich's Tested-by tag[3] for the series onto the three devicetree
patches (ARM and RISC-V) that I think it most affects. It isn't possible
to apply a tag to a whole series at present and in any case there are
changes in v7.

This series is available at u-boot-dm/ofb-working

[1] https://patchwork.ozlabs.org/project/uboot/patch/20211207001209.3467163-2-sjg@chromium.org/
[2] https://lore.kernel.org/u-boot/20211205133207.GW1220664@bill-the-cat/T/#mcd8c0258827fbc1bb3000b7ff9ba0929df1ddcb2
[3] https://lore.kernel.org/u-boot/93913911-4d20-d28f-ee04-739985184c5e@canonical.com/raw

3 files changed, 46 insertions, 1 deletions

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 39f03398ed..b4e63bc0ca 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -175,7 +175,9 @@ u_boot_dtsi_options_raw = $(warning Automatic .dtsi inclusion: options: \
 
 # Uncomment for debugging
 # This shows all the files that were considered and the one that we chose.
-# u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
+ifdef DEVICE_TREE_DEBUG
+u_boot_dtsi_options_debug = $(warning $(u_boot_dtsi_options_raw))
+endif
 
 # We use the first match
 u_boot_dtsi = $(strip $(u_boot_dtsi_options_debug) \
diff --git a/scripts/check-of.sh b/scripts/check-of.sh
new file mode 100755
index 0000000000..0f0bf51664
--- /dev/null
+++ b/scripts/check-of.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+# Copyright 2021 Google LLC
+# Written by Simon Glass <sjg@chromium.org>
+#
+# Check that the .config file provided does not try to disable OF_BOARD for
+# boards that use CONFIG_OF_HAS_PRIOR_STAGE
+#
+# Usage
+#    check-of.sh <path to .config> <path to allowlist file>
+#
+# For example:
+#   scripts/check-of.sh b/chromebook_link/u-boot.cfg kconfig_allowlist.txt
+#
+# Exit code is 0 if OK, 3 if the .config is wrong, as above
+
+set -e
+set -u
+
+PROG_NAME="${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