[PATCH v3 1/7] ARM: Align machine_desc.phys_io to a 1MB section

[Catalin Marinas]

On Mon, 2010-06-21 at 10:35 +0100, Russell King - ARM Linux wrote:
> On Mon, Jun 21, 2010 at 10:13:31AM +0100, Catalin Marinas wrote:
> > Platforms like RealView don't pass a section-aligned pointer via the
> > machine_desc structure. This patch aligns the pointer in the
> > __create_page_tables function. Reported by Tony Thompson.
> 
> I still say this is the wrong way.  As I've said before, please fix it
> at the machine_desc initialization point.  

This requirement doesn't seem to be well documented and platforms don't
follow it (e.g. RealView and VExpress). Since it's the head.S code
responsible for this temporary mapping, the platform code wouldn't need
to know whether sections or pages or something else are used to map it.
But io_pg_offst already makes the assumption about sections.

> If you want, pass it as the
> section frame number itself (address >> 20) rather than the address to
> allow for more addressing space.

I would rather go for a PFN to allow more addressing space (but doesn't
solve the section alignment).

For now, I'll send a couple of patches to fix RealView and VExpress
boards.

-- 
Catalin