PC system memory and PCI masters

[fink@post.tau.ac.il (Udi Finkelstein)]

Hello everyone,

I have designed a PCI based DRAM card containing 128MB/256MB, and I want to
know wether I can try mapping it as a normal system memory under NT. I realize
that:
1. The memory latency time is longer than the on board memory.
2. It will not be cached by the L2 cache.

For performance reasons I want the L1 cache to cache my memory (I assume a
device driver will have to be written to add the memory into the NT memory
pool and to enable the L1 cache for that range).

What I am not sure is whether it is safe to turn on the L1 cache for my
memory. What happenes when a PCI master writes data to my card to an address
that is already cached? What happenes under NT when a Bus master tries to
write to an address in the on-board memory that is in the L1 or L2 cache?
Is this handled by hardware or by software?

thanks,
Udi
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