[lkml]   [2002]   [Sep]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRE: Calculating kernel logical address ..
    On Mon, 9 Sep 2002, Imran Badr wrote:

    > So, what you gurus suggest me to do? How can I get physical address of a
    > user buffer (which was originally mmap'ed() from a kmalloc() allocation) and
    > which would also be protable across multiple platforms?
    > Thanks.
    > Imran.

    I think there is a virt_to_bus() macro and its inverse. The 'bus' address
    is what you need to give to bus-masters that do DMA. This is different
    than virt_to_phys(), which happens to be the same on some platforms
    but would not be the same on those, like PPC (Motorola), which have
    separate address spaces for different things (RAM, I/O, etc).

    Isn't this what you want?

    Dick Johnson
    Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
    The US military has given us many words, FUBAR, SNAFU, now ENRON.
    Yes, top management were graduates of West Point and Annapolis.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:28    [W:0.024 / U:0.072 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site