Add arm-generic-fdt machine support in qemu-system-aarch64

[stephanosio]

This commit adds a patch to support the arm-generic-fdt machine type
in qemu-system-aarch64. The arm-generic-fdt machine type is currently
available only in the Xilinx QEMU fork and this patch was generated by
diff-ing the QEMU 4.1 release and the master_next branch of the Xilinx
fork (which is based on the QEMU 4.1 release).

This machine type is required to properly emulate the Xilinx Zynq SoCs
used by the qemu_cortex_r5 platform.

For more details, refer to the issue #132.

Signed-off-by: Stephanos Ioannidis root@stephanos.io

This closes #132.

[galak]

Rather than pulling a huge patch, can we build the arm-generic-fdt as a separate package and point to the xilinx git tree?

I'm concerned about what impact having this huge change has on all the other qemu builds.

[stephanosio]

Rather than pulling a huge patch, can we build the arm-generic-fdt as a separate package and point to the xilinx git tree?

I thought of doing that initially, but it seemed like that would subsequently require quite a few other changes, so I went with this (e.g. updating Zephyr build system to support multiple QEMU versions and potentially restructuring some qemu-related stuff in sdk-ng too).

Most of the changes in the Xilinx repo have to do with only ARM and the peripherals used by the Xilinx SoCs, so the I would expect the impact on other archs to be minimal.

I have run Zephyr test suite for all archs using the patched QEMU and they all seem to be working properly.

If you still prefer to have Xilinx QEMU as a separate package, I will close this PR and create a new one for that.

[galak]

I thought of doing that initially, but it seemed like that would subsequently require quite a few other changes, so I went with this (e.g. updating Zephyr build system to support multiple QEMU versions and potentially restructuring some qemu-related stuff in sdk-ng too).

Most of the changes in the Xilinx repo have to do with only ARM and the peripherals used by the Xilinx SoCs, so the I would expect the impact on other archs to be minimal.

I have run Zephyr test suite for all archs using the patched QEMU and they all seem to be working properly.

I'm also concerned that this couples us to Xilinx release/update cadence for all other qemu platforms. I know there are number of changes Xilinx makes to QEMU that the upstream community hasn't been keen on accepted.

If you still prefer to have Xilinx QEMU as a separate package, I will close this PR and create a new one for that.

If you would that would be appreciated.

[stephanosio]

Superseded by #138.