8250 idma problem - cache?

[Penn, John]

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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