RE: [PATCH] fsldma: use PCI Read Multiple command

Liu Dave-R63238
2009-04-28T01:31:40Z

> > You are assuming the PCI memory space is prefetchable( no
> > side effect) for DMA.
> > Is it possible that DMA is from non-prefetchable memory space?
>
> This should be a safe assumption for this driver. Remember, this
> driver just does offload memcpy, from one region to another. So the
> PCI memory that you are reading from should be just a buffer of data,
> and there should be side-effect of reading it.
>
> However, I would like to see a comment at the top of the file warning
> people that copying from PCI memory will result in prefetched reads.

How about FIFO RAM case?