Re: [PATCH] ACPI: use ioremap_cache()

From: H. Peter Anvin
Date: Mon Dec 27 2010 - 22:35:52 EST


On 12/27/2010 07:21 PM, Shaohua Li wrote:
> RCRB is a memory mapped io. In ICH, it's chipset configuration
> registers. this range can't be cached.
> I thought we should add a check like
> if page is E820_RAM or E820_ACPI then
> cached_map
> else
> uncached_map
> we have page_is_ram() API which just checks E820_RAM, I thought we can
> add a new API to check E820_ACPI.

For x86, that is handled by the MTRRs; for ia64, I would assume
ioremap() handles that somehow, otherwise it wouldn't be able to handle
existing drivers with ioremap() in them.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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