configs/bananapi_m2_zero: new defconfig

The Banana Pi M2 Zero [1] is a board from Sinovoip, based on the
Allwinner H2+ SoC.

It is similar to the other Banana Pi M2* boards, from which this
configuration is inspired.

[1]: http://www.banana-pi.org/m2z.html

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/bananapi/bananapi-m2-zero/boot.cmd

@@ -0,0 +1,7 @@
+setenv bootargs console=ttyS0,115200 earlyprintk root=/dev/mmcblk0p2 rootwait
+
+mmc dev 0
+fatload mmc 0 $kernel_addr_r zImage
+fatload mmc 0 $fdt_addr_r sun8i-h2-plus-bananapi-m2-zero.dtb
+
+bootz $kernel_addr_r - $fdt_addr_r

board/bananapi/bananapi-m2-zero/genimage.cfg

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+image boot.vfat {
+	vfat {
+		files = {
+			"zImage",
+			"sun8i-h2-plus-bananapi-m2-zero.dtb",
+			"boot.scr"
+		}
+	}
+	size = 64M
+}
+
+image sdcard.img {
+	hdimage {
+	}
+
+	partition u-boot {
+		in-partition-table = "no"
+		image = "u-boot-sunxi-with-spl.bin"
+		offset = 8192
+		size = 1040384 # 1MB - 8192
+	}
+
+	partition boot {
+		partition-type = 0xC
+		bootable = "true"
+		image = "boot.vfat"
+	}
+
+	partition rootfs {
+		partition-type = 0x83
+		image = "rootfs.ext4"
+	}
+}

board/bananapi/bananapi-m2-zero/readme.txt

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+Intro
+=====
+
+This default configuration will allow you to start experimenting with the
+Buildroot environment for the Bananapi M2 Zero. With the current configuration
+it will bring-up the board, and allow access through the serial console.
+
+Bananapi M2 Zero link:
+http://www.banana-pi.org/m2z.html
+
+This configuration uses U-Boot mainline and kernel mainline.
+
+How to build
+============
+
+  $ make bananapi_m2_zero_defconfig
+  $ make
+
+Note: you will need access to the internet to download the required
+sources.
+
+How to write the SD card
+========================
+
+Once the build process is finished you will have an image called "sdcard.img"
+in the output/images/ directory.
+
+Copy the bootable "sdcard.img" onto an SD card with "dd":
+
+  $ sudo dd if=output/images/sdcard.img of=/dev/sdX
+  $ sync
+
+Insert the micro SDcard in your Bananapi M2 Zero and power it up. The console
+is on the Debug UART on the CON3 header, with serial settings 115200 8N1.