On Tue, Aug 13, 2002 at 06:00:43PM -0700, Imran Badr wrote:
> Please advise if following sequence of operations are going to help:
>
> alloc memory
> reserve the page
> flush every cache
That's an extremly expensive operation on some platforms and there's no
portable kernel API to do it.
Note that the flush_cache_*() functions are not suitable for I/O as you
want to do it. Many platforms such as i386 implement these functions
as empty functions.
> call ioremap_nocache
You said you intend to remap memory, that is RAM. The ioremap*() functions
will refuse to remap RAM; they're only suitable for other types of memory
such as PCI boards. If the latter was your intension then ioremap_nocache()
will work as intended.
Again, unless your hardware is fucked beyond recognition it'll do a better
job at keeping cache coherence than software.
Ralf
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This archive was generated by hypermail 2b29 : Thu Aug 15 2002 - 22:00:36 EST