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    SubjectRe: PowerPC PCI DMA issues (prefetch/coherency?)
    On Wed, 2009-06-17 at 02:56 +0200, Leon Woestenberg wrote:
    > I use pci_map_sg(), have the device perform either DMA master reads or
    > writes to the bus address using PCIe.
    > After that, I use pci_unmap_sg().
    > My assumption is that pci_unmap_sg() either makes the cache coherent
    > or invalidated and thus I do not need to take further actions.
    > This is on a MPC83xx or 85xx system.
    > Is this assumption correct?

    It is, as far as I understand things :-) Those APIs are fun.

    You should only need the explicit sync calls if you are going to peek or
    poke at the DMA mapped memory before you unmap it.


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