On Apr 7, 2008, at 11:20 AM, Scott Wood wrote:
On Mon, Apr 07, 2008 at 08:09:57AM -0500, Kumar Gala wrote:
On Apr 6, 2008, at 6:48 PM, Paul Mackerras wrote:
More generally, I think we need to take an overall look at what
things
we are using fixed virtual addresses for, and why they need to be
fixed. If there are indeed several such things then we can
introduce
the fixmap stuff.
The list as I see it:
* kmap
* pci-e config for 4xx/83xx
* kexec/kdump (ben commented on this when Dale posted his patches for
ppc32 support)
future:
* possible usage by HV
since we already have three users and a possible fourth it seems
like a
useful change.
Another possible use is a BAT/TLB1 mapping for SoC registers (or
anything
else on the board which is frequently accessed), which can be reused
by
ioremap() to avoid wasting normal TLB entries, and to facilitate early
debugging.
x86 has an early ioremap() that is implemented on top of their fixmap
usage that we could also steal if desired :)
- k
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