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    SubjectRe: /proc/bus/isa?

    > Some applications need to be able to access the ISA I/O and ISA memory spaces.
    > On Intel, this is easy because you know where those spaces are (at 0 :-).
    > On other architectures that have memory mapped I/O, things are more complex
    > because the addresses are not fixed. They may even be different for different
    > machines within the same architecture. E.g. on Linux/PPC, this is the case for
    > the PReP and CHRP platforms. So the application has to be informed of the base
    > addresses to mmap.
    > One solution would be to add 2 lines to /proc/cpuinfo, like
    > isa_io_base: 0xf8000000
    > isa_mem_base: 0xf7000000
    > (for CHRP LongTrail).
    > Another solution (IMHO better) would be to add /proc/bus/isa/io and
    > /proc/bus/isa/mem. On machines with memory mapped I/O, you can mmap() these, on
    > ordinary PCs you have to use read/write. The advantage of a /proc/bus/isa is
    > that you can add ISA PnP (yuk) device identifation later (cfr. the other
    > /proc/bus/ drivers).
    > Or make them real memory devices (char major 1): /dev/isa_io and /dev/isa_mem?
    > What do you think?

    It would be better to solve these issues for all buses at once. I plan to
    include such thing in my resource manager code I'll work on in those golden and
    long-awaited 2.3 days. I'd also like to add some basic I/O support to glibc or
    create a I/O library, so that processes needing raw I/O will be portable at
    least across different Linux architectures.

    Have a nice fortnight
    Martin `MJ' Mares <>
    Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
    "DOS never says "EXCELLENT command or filename"..."

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