configs/raspberrypi2_64: new defconfig

This configuration builds an image for the Raspberry Pi 2 Rev 1.2
(64-bit).

Note: Raspberry Pi 2 Model B Rev 1.2[1] switched from BCM2836[2] to
BCM2837[3] that is 64-bit.

	BCM2836[2]

	The Broadcom chip used in the Raspberry Pi 2 Model B. The
	underlying architecture in BCM2836 is identical to BCM2835. The
	only significant difference is the removal of the ARM1176JZF-S
	processor and replacement with a quad-core Cortex-A7 cluster.

	BCM2837[3]

	This is the Broadcom chip used in the Raspberry Pi 3 Model B,
	later models of the Raspberry Pi 2 Model B, and the Raspberry Pi
	Compute Module 3. The underlying architecture of the BCM2837 is
	identical to the BCM2836. The only significant difference is the
	replacement of the ARMv7 quad core cluster with a quad-core ARM
	Cortex A53 (ARMv8) cluster.

	The ARM cores run at 1.2GHz, making the device about 50% faster
	than the Raspberry Pi 2. The VideoCore IV runs at 400MHz.

[1]: https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#flagship-series
[2]: https://www.raspberrypi.com/documentation/computers/processors.html#bcm2836
[3]: https://www.raspberrypi.com/documentation/computers/processors.html#bcm2837

Signed-off-by: Gaël PORTAY <gael.portay+rtone@gmail.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

board/raspberrypi/config_2_64bit.txt

@@ -0,0 +1,26 @@
+# Please note that this is only a sample, we recommend you to change it to fit
+# your needs.
+# You should override this file using BR2_PACKAGE_RPI_FIRMWARE_CONFIG_FILE.
+# See http://buildroot.org/manual.html#rootfs-custom
+# and http://elinux.org/RPiconfig for a description of config.txt syntax
+
+start_file=start.elf
+fixup_file=fixup.dat
+
+kernel=Image
+
+# To use an external initramfs file
+#initramfs rootfs.cpio.gz
+
+# Disable overscan assuming the display supports displaying the full resolution
+# If the text shown on the screen disappears off the edge, comment this out
+disable_overscan=1
+
+# How much memory in MB to assign to the GPU on Pi models having
+# 256, 512 or 1024 MB total memory
+gpu_mem_256=100
+gpu_mem_512=100
+gpu_mem_1024=100
+
+# enable 64bits support
+arm_64bit=1

board/raspberrypi/readme.txt

@@ -54,6 +54,10 @@ For model 2 B:
 
   $ make raspberrypi2_defconfig
 
+or for model 2 B (Rev 1.2, model B3 without wireless LAN and Bluetooth, 64 bit):
+
+  $ make raspberrypi2_64_defconfig
+
 For model 3 B, B+, CM3 and CM3+:
 
   $ make raspberrypi3_defconfig

board/raspberrypi2-64

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

configs/raspberrypi2_64_defconfig

@@ -0,0 +1,34 @@
+BR2_aarch64=y
+BR2_ARM_FPU_VFPV4=y
+BR2_TOOLCHAIN_EXTERNAL=y
+BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y
+BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_AARCH64_GLIBC_STABLE=y
+BR2_GLOBAL_PATCH_DIR="board/raspberrypi/patches"
+BR2_DOWNLOAD_FORCE_CHECK_HASHES=y
+BR2_SYSTEM_DHCP="eth0"
+BR2_ROOTFS_POST_BUILD_SCRIPT="board/raspberrypi2-64/post-build.sh"
+BR2_ROOTFS_POST_IMAGE_SCRIPT="board/raspberrypi2-64/post-image.sh"
+BR2_LINUX_KERNEL=y
+BR2_LINUX_KERNEL_CUSTOM_TARBALL=y
+BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="$(call github,raspberrypi,linux,cd231d4775b14f228606c09f219b48308f6ab3aa)/linux-cd231d4775b14f228606c09f219b48308f6ab3aa.tar.gz"
+BR2_LINUX_KERNEL_DEFCONFIG="bcm2711"
+BR2_LINUX_KERNEL_DTS_SUPPORT=y
+BR2_LINUX_KERNEL_INTREE_DTS_NAME="broadcom/bcm2710-rpi-2-b"
+BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
+BR2_PACKAGE_BUSYBOX_SHOW_OTHERS=y
+BR2_PACKAGE_XZ=y
+BR2_PACKAGE_RPI_FIRMWARE=y
+BR2_PACKAGE_RPI_FIRMWARE_BOOTCODE_BIN=y
+BR2_PACKAGE_RPI_FIRMWARE_VARIANT_PI=y
+BR2_PACKAGE_RPI_FIRMWARE_CONFIG_FILE="board/raspberrypi2-64/config_2_64bit.txt"
+# BR2_PACKAGE_RPI_FIRMWARE_INSTALL_DTB_OVERLAYS is not set
+BR2_PACKAGE_KMOD=y
+BR2_PACKAGE_KMOD_TOOLS=y
+BR2_TARGET_ROOTFS_EXT2=y
+BR2_TARGET_ROOTFS_EXT2_4=y
+BR2_TARGET_ROOTFS_EXT2_SIZE="120M"
+# BR2_TARGET_ROOTFS_TAR is not set
+BR2_PACKAGE_HOST_DOSFSTOOLS=y
+BR2_PACKAGE_HOST_GENIMAGE=y
+BR2_PACKAGE_HOST_KMOD_XZ=y
+BR2_PACKAGE_HOST_MTOOLS=y