On Apr 7, 2008, at 6:51 PM, Benjamin Herrenschmidt wrote:
On Mon, 2008-04-07 at 11:20 -0500, Scott Wood wrote:
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.
As far as the above is concerned, I'm not too fan of fixed virtual
addresses. I'd rather dynamically assign it. But we can do it.
I'm in agreement with Ben here. On Freescale parts that could mean
using up to 16M of virtual address space while in reality we may only
need a handful of 4k pages to cover SoC registers that we are truly
accessing at runtime.
However I think there might be some utility to have an early ioremap
mappings for debug.
- k
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