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    SubjectRE: DMA and Cache coherency on machines without hardware enforced
    Date
    Pete Zaitcev [mailto:zaitcev@metabyte.com] wrote:
    > Also note that if one wants to produce the bus address to
    > program a DMA master he/she must use virt_to_bus(page), and NOT
    > virt_to_bus(ptr).

    Where did you get this requirement from? That isn't what
    Documentation/IO-mapping.txt appears to indicate.

    It gives a prototype of
    bus_addr = virt_to_bus(virt_addr);
    and even the examples don't seem to indicate that it is anything other than
    an address that is passed in.

    When you say you must use virt_to_bus(page), I'm guessing you mean that the
    address must be page aligned.

    -Bret

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