system/boot: Begin factoring gFDT out of non-u-boot code

Change-Id: Ibe010c6c7ed71a20fc852ce6c72c6f32b98dfad2
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2292
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

sparc: boot mmu support

Get enough of the mmu working to be able to allocate memory.

Unlike on PowerPC, we get both address and size as 64bit values. So
adjust of_region to allow this.

Also unlike the PPC port, we do not drive the hardware directly, instead we
rely on the openboot primitives to manage the translation table. This
allows staying independant of the hardware, which is a good idea at
least for the bootloader (we can do actual hardware things in the
kernel)

Change-Id: Ifa57619d3a09b8f707e1f8640d8b4f71bb717e2a
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1482
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>

u-boot: PPC: Fix warnings

More small C++11 tweaks.

Whitespace cleanup

U-Boot: PPC: Implement Book-E MMU support in bootloader

Unlike Classic PPC, Book-E CPUs do not have hardware page-table walk,
rather only a limited set of software-managed TLBs. Also, translation
is never disabled even when page-faulting.

The Linux Book-E port pins part of the RAM in one or more TLBs, and
allocates kernel memory from it for the kernel itself and exception
vectors, as well as page tables.
cf. http://kernel.org/doc/ols/2003/ols2003-pages-340-350.pdf

We take a similar approach, but instead of using a tree-like page
directory we reserve a large part of this mapped range for an
hashed page table similar to the Classic one, to later allow
factoring code out. The kernel and boot modules will also be
allocated there, and the rest should be used as SLAB areas.

Note doing so will not allow implementing proper permissions for
the areas allocated there since they are all handled by a single TLB.

Also note Book-E does not standardize the MMU implementation itself.
For now only AMCC440 type MMU is supported. This will need to be
cleaned up later on.

U-Boot: PPC: Copy the memory sizing code from OF

Just an exercise to see how well the OF wrapper works.
Had to adjust cause the FDT I had had /memory node,
but no memory prop on /chosen.

u-boot: PPC: Fix warnings

More small C++11 tweaks.

Whitespace cleanup

U-Boot: PPC: Implement Book-E MMU support in bootloader

Unlike Classic PPC, Book-E CPUs do not have hardware page-table walk,
rather only a limited set of software-managed TLBs. Also, translation
is never disabled even when page-faulting.

The Linux Book-E port pins part of the RAM in one or more TLBs, and
allocates kernel memory from it for the kernel itself and exception
vectors, as well as page tables.
cf. http://kernel.org/doc/ols/2003/ols2003-pages-340-350.pdf

We take a similar approach, but instead of using a tree-like page
directory we reserve a large part of this mapped range for an
hashed page table similar to the Classic one, to later allow
factoring code out. The kernel and boot modules will also be
allocated there, and the rest should be used as SLAB areas.

Note doing so will not allow implementing proper permissions for
the areas allocated there since they are all handled by a single TLB.

Also note Book-E does not standardize the MMU implementation itself.
For now only AMCC440 type MMU is supported. This will need to be
cleaned up later on.

U-Boot: PPC: Copy the memory sizing code from OF

Just an exercise to see how well the OF wrapper works.
Had to adjust cause the FDT I had had /memory node,
but no memory prop on /chosen.