Nios II - Data cache problem

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The problem is due to data cache in Nios II processor because without it my software works :)

I don't use ioremap_nocache. May I change something in my driver if I move from a processor with no data cache to a processor with data cache?

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You have to use ioremap_nocache to get a virtual address from your physical address. Then do all your access using that address. This will work with or without an MMU.