[PATCH 0/5]arm64: Add multiboot support (via fdt) for Xen boot

[Fu Wei <fu.wei@linaro.org>]

- This multiboot support is built into linux module for aarch64.
    
- The implementation for Xen is following  <Multiboot on ARM Specification>:
http://wiki.xen.org/wiki/Xen_ARM_with_Virtualization_Extensions/Multiboot
and xen/docs/misc/arm/device-tree/booting.txt in Xen source code.

- The example of this support is <How to boot Xen with GRUB on AArch64 the Foundation FVP model>
https://wiki.linaro.org/LEG/Engineering/Grub2/Xen_booting_on_Foundation_FVP_model_by_GRUB
    
- This adds support for the Xen Multiboot on ARM specification for arm64,
enabling config file portability across the architectures.
    
- The multiboot command is currently x86-only, so reusing these command names
should not conflict with any future additions of ARM support to multiboot2.
    
- The reason of adding this functionality to the existing "linux" module
rather than "multiboot(2)"
  (1)multiboot is x86 only
  (2)Multiboot is added to "linux" module because it reuses existing code.

- Some changes in original linux module code
  Move some #define from grub-core/loader/arm64/linux.c to include/grub/arm64/linux.h 
  Make some shared functions for multiboot.c
  Remove "loaded" checking in the grub_cmd_devicetree of linux.c

- Add grub_fdt_set_reg64 macro into fdt.h header file for inserting "reg" properiy,
while #address-cells = <0x2> and  #size-cells = <0x2>

- Add the introduction of multiboot/module command in docs/grub.texi

This multiboot support will be built in linux module for aarch64,
and can not be used alone.

 docs/grub.texi                     |  10 +
 grub-core/Makefile.core.def        |   1 +
 grub-core/loader/arm64/linux.c     |  72 ++---
 grub-core/loader/arm64/multiboot.c | 593 +++++++++++++++++++++++++++++++++++++
 include/grub/arm64/linux.h         |  11 +
 include/grub/arm64/multiboot.h     | 115 +++++++
 include/grub/fdt.h                 |  12 +
 7 files changed, 778 insertions(+), 36 deletions(-)
 create mode 100644 grub-core/loader/arm64/multiboot.c
 create mode 100644 include/grub/arm64/multiboot.h


Signed-off-by: Fu Wei <fu.wei@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
-- 
1.8.3.1