I am implementing IDMA, 2 channels(rx/tx), between the 8250
and a slow device attached to the local bus. I seem
to have a transmit problem that could be explained
by the dcache holding the packet, its very small, and
the buffer being transmitted having old data or zeros
in it.
I have been reading through the archives regarding :
invalidating the dcache - it's a nop for 8260
snooping - tried enabling it on tx DGBL, no difference
SIUMCR - ESE is enabled
using local bus memory instead of 603 memory for buffers
I would rather use 603 memory
the 8260 is fully cache coherent so you don't have
to invalidate the dcache.
Now I am at the point of needing some clarification.
1. Do I have to invalidate dcache and if so how?
2. Has anyone used the IDMA with 603 memory or must
I use local bus memory?
John Penn
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