configs/imx8mn_bsh_smm_s2_pro_defconfig: new defconfig

BSH SMM S2 PRO (SystemMaster S2 Pro) Board is an add-on board which
provide input and output interfaces to a dedicated carrier board. It is
designed mainly to provide graphical/video and connectivity interfaces
to the appliance.

Board support package includes the following components:
- mainline Linux kernel 6.1.6
- mainline U-Boot 2022-07
- Default packages from buildroot

https://www.apertis.org/reference_hardware/imx8mn_bsh_smm_s2pro_setup/

Add Ariel D'Alessandro and Dario Binacchi as co-maintainer, we work
together on platform mainline

Build and tested using:
docker pull registry.gitlab.com/buildroot.org/buildroot/base:20220105.2314

Cc: Ariel D'Alessandro <ariel.dalessandro@collabora.com>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Heiko Thiery <heiko.thiery@gmail.com>
Cc: Giulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: Heiko Thiery <heiko.thiery@gmail.com>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Tested-by: Ariel D'Alessandro <ariel.dalessandro@collabora.com>
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/bsh/imx8mn-bsh-smm-s2-pro/extlinux.conf

@@ -0,0 +1,4 @@
+label buildroot
+  kernel /boot/Image
+  devicetree /boot/freescale/imx8mn-bsh-smm-s2pro.dtb
+  append root=PARTUUID=%PARTUUID% rootwait rw

board/bsh/imx8mn-bsh-smm-s2-pro/flash.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+if [ $# -eq 0 ]; then
+    OUTPUT_DIR=output
+else
+    OUTPUT_DIR=$1
+fi
+
+if ! test -d "${OUTPUT_DIR}" ; then
+    echo "ERROR: no output directory specified."
+    echo "Usage: $0 OUTPUT_DIR"
+    echo ""
+    echo "Arguments:"
+    echo "    OUTPUT_DIR    The Buildroot output directory."
+    exit 1
+fi
+
+IMAGES_DIR=${OUTPUT_DIR}/images
+
+${OUTPUT_DIR}/host/bin/uuu -v -b emmc_all \
+  ${IMAGES_DIR}/flash.bin \
+  ${IMAGES_DIR}/sdcard.img
+

board/bsh/imx8mn-bsh-smm-s2-pro/genimage.cfg

@@ -0,0 +1,17 @@
+image sdcard.img {
+	hdimage {
+		partition-table-type = "gpt"
+	}
+
+	partition imx-boot {
+		in-partition-table = "no"
+		image = "flash.bin"
+		offset = 32K
+	}
+
+	partition rootfs {
+		offset = 8M
+		image = "rootfs.ext4"
+		partition-uuid = %PARTUUID%
+	}
+}

board/bsh/imx8mn-bsh-smm-s2-pro/post-build.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+BOARD_DIR="$(dirname $0)"
+PARTUUID="$($HOST_DIR/bin/uuidgen)"
+
+install -d "$TARGET_DIR/boot/extlinux/"
+sed "s/%PARTUUID%/$PARTUUID/g" "$BOARD_DIR/extlinux.conf" > "$TARGET_DIR/boot/extlinux/extlinux.conf"
+sed "s/%PARTUUID%/$PARTUUID/g" "$BOARD_DIR/genimage.cfg" > "$BINARIES_DIR/genimage.cfg"

board/bsh/imx8mn-bsh-smm-s2-pro/post-image.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+support/scripts/genimage.sh -c ${BINARIES_DIR}/genimage.cfg

board/bsh/imx8mn-bsh-smm-s2-pro/readme.txt

@@ -0,0 +1,73 @@
+i.MX8MN BSH SMM S2 PRO
+======================
+
+How to build it
+---------------
+
+Configure buildroot:
+
+  $ make imx8mn_bsh_smm_s2_pro_defconfig
+
+Change settings to fit your needs (optional):
+
+  $ make menuconfig
+
+Compile everything and build the rootfs image:
+
+  $ make
+
+
+Result of the build
+-------------------
+
+After building, the output/images directory contains:
+
+  output/images/
+    ├── bl31.bin
+    ├── Image
+    ├── flash.bin
+    ├── ddr3*
+    ├── rootfs.ext2
+    ├── rootfs.ext4 -> rootfs.ext2
+    ├── rootfs.tar
+    ├── sdcard.img
+    ├── u-boot.bin
+    ├── u-boot-nodtb.bin
+    └── u-boot-spl.bin
+
+
+Preparing the board
+-------------------
+
+Plug the USB type A to micro B cable into the USB Debug
+Connector (DBG UART). Use serial port settings 115200 8N1
+to access the debug console.
+
+Plug another USB type A to micro B cable into the USB-OTG
+Connector (USB1). This connection is used to flash the board
+firmware using the Freescale/NXP UUU tool.
+
+Connect the power supply/adaptor to the DC Power Jack (labelled
++5V).
+
+
+Flashing the emmc card image
+----------------------------
+
+Power up the board by switching on the Power ON Switch, which is
+placed right next to the DC Jack.
+
+Enter the following U-Boot commands on the debug serial console:
+
+  $ fastboot usb 0
+
+Flash the images on eMMC. On your computer, run:
+
+  $ board/bsh/imx8mn-bsh-smm-s2-pro/flash.sh output/
+
+
+Booting the board
+-----------------
+
+By default the bootloader will search for the first valid image,
+starting with the internal eMMC.