configs/mx6udoo: Add initial support

Add the initial support for mx6q/dl udoo boards.

For information about these boards, please visit:
http://www.udoo.org/

In linux.fragment we disable USB support for now because kernel 4.8
hangs on udoo board.

This is been addressed by Peter Chen's kernel patch series that provides
a standard way to reset a USB hub.

When such series hit mainline, then we can bump the kernel and remove
linux.fragment.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

board/udoo/genimage.cfg

@@ -0,0 +1,48 @@
+# Minimal microSD card image for Udoo MX6Q/DL boards
+#
+# We mimic the .sdcard Freescale's image format for i.MX6:
+# * the microSD card must have 1 kB free space at the beginning,
+# * U-Boot is dumped as is,
+# * a FAT partition at offset 16 MB is containing zImage and dtbs,
+# * a single root filesystem partition is required (Ext4 in this case).
+#
+
+image boot.vfat {
+	vfat {
+		files = {
+			"imx6q-udoo.dtb",
+			"imx6dl-udoo.dtb",
+			"zImage"
+		}
+	}
+	size = 16M
+}
+
+image sdcard.img {
+	hdimage {
+	}
+
+	partition SPL {
+		in-partition-table = "no"
+		image = "SPL"
+		offset = 1K
+	}
+
+	partition u-boot {
+		in-partition-table = "no"
+		image = "u-boot.img"
+		offset = 69K
+	}
+
+	partition boot {
+		partition-type = 0xC
+		bootable = "true"
+		image = "boot.vfat"
+		offset = 16M
+	}
+
+	partition rootfs {
+		partition-type = 0x83
+		image = "rootfs.ext4"
+	}
+}

board/udoo/linux.fragment

@@ -0,0 +1 @@
+CONFIG_USB=n

board/udoo/post-image.sh

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+#!/usr/bin/env bash
+
+BOARD_DIR="$(dirname $0)"
+GENIMAGE_CFG="${BOARD_DIR}/genimage.cfg"
+GENIMAGE_TMP="${BUILD_DIR}/genimage.tmp"
+
+rm -rf "${GENIMAGE_TMP}"
+
+genimage \
+  --rootpath "${TARGET_DIR}" \
+  --tmppath "${GENIMAGE_TMP}" \
+  --inputpath "${BINARIES_DIR}" \
+  --outputpath "${BINARIES_DIR}" \
+  --config "${GENIMAGE_CFG}"

board/udoo/readme.txt

@@ -0,0 +1,17 @@
+Udoo MX6Q/DL board
+
+For information about MX6 Udoo boards:
+http://www.udoo.org/
+
+To build a minimal support for these boards:
+
+    $ make mx6udoo_defconfig
+    $ make
+
+Buildroot prepares a bootable "sdcard.img" image in the output/images/
+directory, ready to be dumped on a micro SD card:
+
+dd if=output/images/sdcard.img of=/dev/<your-microsd-device>
+
+For details about the medium image layout, see the definition in
+board/udoo/genimage.cfg.