On Wed, Sep 21, 2011 at 10:41:49AM +0100, Pawel Moll wrote:

quoted

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2. Single DT_MACHINE_START matching (the most generic) "arm,vexpress"
and doing (rougly) this in v2m_map_io:

of_scan_flat_dt(v2m_dt_iotable_init, NULL);

v2m_dt_iotable_init(...)
{
	if (depth != 0)
		return 0;
	if (of_flat_dt_is_compatible(node, "arm,vexpress-legacy"))
		iotable_init(v2m_io_desc_legacy);
	else (of_flat_dt_is_compatible(node, "arm,vexpress-rs1"))
		iotable_init(v2m_io_desc_rs1);
	else
		panic();
}

Neither of them seem particularly appealing... ;-)

But I think both ways would be acceptable in the end. It's not a lot
of extra code either way. In the second case, I would probably have
the legacy case as a special variant of the map_io function and have
all others be the default instead of falling back to panic though.

Ok, I'll go (roughly) that way.

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In my case it's sysreg and sysctl. There are two more users of static
mappings: timer01 and timer23, but they could at some point do ioremap()
on their own (especially with Nico's changes).

Well, I think with Nico's cahnges, you /can/ actually do ioremap for
areas that have been mapped through the iotable before kmalloc is up.
IIRC, omap does this for a number of peripherals.

It's a bit of a hack, but I think it's much better than taking hardcoded
addresses.

Yes, I was thinking about that last night. If you think it's acceptable
I'll do this (killing MMIO_P2V on the way ;-)

quoted

With the combination of the points mentioned above, you should be
able to do:

- map the entire I/O area in map_io(), depending on the board
- have an __iomem pointer for the sysreg
- populate that pointer using of_iomap from the device tree address
  before you first access it.

Do you think that would work?

Yes, I suppose so. The last bit (getting the offset from DT) will be a
little ugly, I think, but let's wait till I get some code done.

I won't attempt to modify the rest of the patch yet, but we can roll
changes in when you've decided on a way forward.

Alternatively, the requisite changes can be done as patches on top of
the basic patch -- since the initial patch doesn't attempt to support
multiple core tiles anyway.

Cheers
---Dave