Improve meta-virt-xen.inc by moving all the Raspberry Pi 4 config
settings to a new xen-raspberrypi4-64.inc file in the raspberrypi
dynamic layer.

The new .inc file is included only for the raspberrypi4-64 MACHINE,
so the config settings no longer need to be applied using overrides.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

The 5.10 version of the Linux Yocto kernel supports running Xen on the
Raspberry Pi 4, so the previous preference for linux-yocto-dev can be
replaced.

Use the ?= operator to set the kernel preference now since
meta-raspberrypi commit e0b4b8c5d introduced use of the weak default
for kernel preference in that layer to allow this here.

KERNEL_DEVICETREE needs to be set to match the build outputs of the
selected kernel, in this case: "broadcom/bcm2711-rpi-4-b.dtb"

Tested with kernel version:
 SRCREV_machine = "cf5b0320cf4544d3db9ce3ddd6ddb7553a610651"
 SRCREV_meta="031f6c76e488a3563f35258c72ff1de3e25a512e"

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

Enable linux-yocto-dev as the Linux kernel for Xen on the
Raspberry Pi 4, with the bcm-2xxx-rpi4 KMACHINE and KBRANCH.

Set a Raspberry Pi SD card variable to increase the size of the boot
partition to accommodate both the kernel and the Xen hypervisor.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

Retiring use of the downstream vendor kernel for use with Xen.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

The GIC that is needed by Xen can be enabled via the rpi-config recipe
variable. Fixes the build after the upstream recipe changed recently.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

The sdcard class in the meta-raspberrypi layer is now extensible with
support for adding files such as hypervisor binaries to the boot
partition, so this layer can switch to use that and drop the custom
sdcard bbclass.

Uses the new RPI_SDIMG_EXTRA_DEPENDS and DEPLOYPAYLOAD variables,
and: IMAGE_CLASS: sdcard_image-rpi-xen => sdcard_image-rpi
    IMAGE_FSTYPE: rpi-xen-sdimg => rpi-sdimg

Please note that the filename suffix of the image is changed by this.

Also apply _raspberrypi4-64 scoping to the Raspberry Pi settings.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

These settings are not needed here. Serial configuration is done
in the bsp layer. Tested and working on the Raspberry Pi 4.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

Aligns with Yocto's current kernel version.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

At the moment the regular meta-raspberrypi SD card class does not allow
for optional inclusion of extra files in the SD card boot partition
without requiring those same files be present in the root filesystem.
This affects hypervisor binaries, such as Xen, which do not necessarily
belong within the guest filesystem.

As a workaround, inherit the sdcard_image-rpi.bbclass and clone the
main IMAGE_CMD function, adding the Xen-specific deploy that is needed.
This can be retired when the parent class has extensibility added.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

These settings are necessary for Xen and enabling them here, using the
same mechanism that is used by k8s in this layer, simplifies building
images for Xen.

- Ensure that Xen mode is enabled in QEMU.
- On ARM platforms: enable Flattened Device Tree (FDT) support.

Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>