configs: add Raspberry Pi 3 defconfig

So far identical to the rpi2 one except for the dts file as the SW runs in
32bit mode.

[Peter: extend commit message]
Signed-off-by: Ubaldo Porcheddu <ubaldo@eja.it>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/raspberrypi/genimage-raspberrypi3.cfg

@@ -0,0 +1,30 @@
+image boot.vfat {
+  vfat {
+    files = {
+      "bcm2710-rpi-3-b.dtb",
+      "rpi-firmware/bootcode.bin",
+      "rpi-firmware/cmdline.txt",
+      "rpi-firmware/config.txt",
+      "rpi-firmware/fixup.dat",
+      "rpi-firmware/start.elf",
+      "kernel-marked/zImage"
+    }
+  }
+  size = 32M
+}
+
+image sdcard.img {
+  hdimage {
+  }
+
+  partition boot {
+    partition-type = 0xC
+    bootable = "true"
+    image = "boot.vfat"
+  }
+
+  partition rootfs {
+    partition-type = 0x83
+    image = "rootfs.ext4"
+  }
+}

board/raspberrypi/readme.txt

@@ -6,7 +6,8 @@ Intro
 These instructions apply to all models of the Raspberry Pi:
   - the original models A and B,
   - the "enhanced" models A+ and B+,
-  - the model B2 (aka Raspberry Pi 2).
+  - the model B2 (aka Raspberry Pi 2)
+  - the model B3 (aka Raspberry Pi 3).
 
 How to build it
 ===============
@@ -21,10 +22,14 @@ For models A, B, A+ or B+:
 
   $ make raspberrypi_defconfig
 
-And for model 2 B:
+For model 2 B:
 
   $ make raspberrypi2_defconfig
 
+For model 3 B:
+
+  $ make raspberrypi3_defconfig
+
 Build the rootfs
 ----------------
 
@@ -46,6 +51,7 @@ After building, you should obtain this tree:
     +-- bcm2708-rpi-b.dtb           [1]
     +-- bcm2708-rpi-b-plus.dtb      [1]
     +-- bcm2709-rpi-2-b.dtb         [1]
+    +-- bcm2710-rpi-3-b.dtb         [1]
     +-- boot.vfat
     +-- kernel-marked/zImage        [2]
     +-- rootfs.ext4

board/raspberrypi3

@@ -0,0 +1 @@
+raspberrypi

configs/raspberrypi3_defconfig

@@ -0,0 +1,36 @@
+BR2_arm=y
+BR2_cortex_a7=y
+BR2_ARM_EABIHF=y
+BR2_ARM_FPU_NEON_VFPV4=y
+
+BR2_TOOLCHAIN_BUILDROOT_CXX=y
+
+BR2_SYSTEM_DHCP="eth0"
+
+# Linux headers same as kernel, a 4.1 series
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_1=y
+
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_GIT=y
+BR2_LINUX_KERNEL_CUSTOM_REPO_URL="https://github.com/raspberrypi/linux.git"
+BR2_LINUX_KERNEL_CUSTOM_REPO_VERSION="20fe468af4bb40fec0f81753da4b20a8bfc259c9"
+BR2_LINUX_KERNEL_DEFCONFIG="bcm2709"
+
+# Build the DTB from the kernel sources
+BR2_LINUX_KERNEL_DTS_SUPPORT=y
+BR2_LINUX_KERNEL_INTREE_DTS_NAME="bcm2710-rpi-3-b"
+
+BR2_PACKAGE_RPI_FIRMWARE=y
+# BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTB_OVERLAYS is not set
+
+# Required tools to create the SD image
+BR2_PACKAGE_HOST_DOSFSTOOLS=y
+BR2_PACKAGE_HOST_GENIMAGE=y
+BR2_PACKAGE_HOST_MTOOLS=y
+
+# Filesystem / image
+BR2_TARGET_ROOTFS_EXT2=y
+BR2_TARGET_ROOTFS_EXT2_4=y
+# BR2_TARGET_ROOTFS_TAR is not set
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/raspberrypi3/post-build.sh"
+BR2_ROOTFS_POST_IMAGE_SCRIPT="board/raspberrypi3/post-image.sh"