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    SubjectRe: readl/writel: swap or not to swap
    Yasushi SHOJI wrote:
    > At Sat, 13 Nov 2004 21:20:03 +0900,
    > yashi wrote:
    > [...]
    >
    >>>Why not just use __raw_readl/__raw_writel?
    >>>
    >>>That's what they exist for, and they still do any IO accesses correctly,
    >>>which a direct store does not do (it would seriously break on older
    >>>alphas, for example).
    >>
    >>sorry for a dumb question but should readl/writel on big endian system
    >>swap like ppc does?
    >
    >
    > I guess everyone is busy hacking. but can at least someone give me a
    > hit?
    >
    > I'm worring about this issue because I'm about to use two deferent
    > linux arch on same board. it's based on reconfigurable device so I
    > can configure to have deferent cpu on it.
    >
    > if you are using two deferent arch of linux, it's natual to think you
    > want to share all device drivers. but if one arch swap with readl and
    > the other doesn't, I have to abstruct these low level access
    > methods. (given that those to arch are same endian and connected with
    > same bus and to the same devices)
    >
    > is there any rule we should follow? Is the ppc way the right
    > direction to follow? I can ifdef anytime for my own use but I just
    > want to know what _should_ be done.


    readl()/writel() are defined as being for the PCI bus (little endian).
    As such, they should swap on big endian platforms.

    Jeff


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