Help me!

You're not giving us much to work with. For example, what is this "wrong result?"

There is a bit more to doing a DMA transfer than just setting up the DMA registers.

o Does the transfer complete (without errors?) according to the register interface? o Are you expecting/receiving an interrupt? o If the register interface indicates completion, is the expected data incorrect?

Working with PCI can be ... interesting, and there are many details that need to be correct. On top of that, processors that operate with PCI buses can add a few layers of fun themselves (e.g. interrupt controllers, virtual addresses and caches.)

If you want help, you need to give details.

Oh, I am sorry.I did not say that clearly.

My driver can transfer data, and I can handle these data after I received a DMA DONE interrupt.The data in the FIFO are like these:

Into a DMA source buffer?

What do you mean by "I can handle these data?"

Do you mean that you can still "see" the data in the DMA source buffer after the transfer is complete?

What FIFO? Is the FIFO part of a peripheral?

That sounds like a typical operation to perform on the receive FIFO of a peripheral.

In other words, you can read the FIFO and copy the contents to a receive buffer just fine with no DMA. Correct?

I assume the DMA controller indicates that it completed the transfer and that the DMA destination buffer contains these values.

If that is the case, and if you have setup the DMA controller correctly (source address, destination address, count, etc.), and you have done your physical-virtual-bus address mapping correctly that the most likely problem is one of cache coherency.

You have not said anything about the type of processor you are using or about its cache coherency protocol with respect to the DMA controller.

Does the processor's data cache snoop the DMA destination memory? If not you may need to manually invalidate cache associated with the DMA destination buffer.

IOW, what you may be seeing is stale data in your cache.