2.5 or 2.4 kernel profiling
Dan Malek
dan at mvista.com
Wed Dec 13 08:03:19 EST 2000
Brian Ford wrote:
> Does your statement mean that 60x bus memory is mapped
> _PAGE_COHERENT? What is the exact meaning of the GBL bit in the FCRx
> register?
The GBL flag in the FCRx is orthogonal to the PAGE_COHERENT (M in WIMG)
of the processor. Since the CPM is a bus master, the GBL flag is used
to indicate whether it should announce memory updates in the cache
protocol. The CPM shared memory is mapped uncached to the processor,
and I don't see any reason to do that differently. For some reason,
I believe the GBL flag also ensures the CPM DMA will snoop the processor
cache, and setting PAGE_COHERENT isn't necessary. I don't know why
I think this, except it appears to work that way :-). Logically, we
should be required to set PAGE_COHERENT......It's a note on my board,
I'll keep looking at it.
Thanks.
-- Dan
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