high addresses & cache - VxWorks

This is a discussion on high addresses & cache - VxWorks ; Hello all, I'd like to access PCI memory address space located in memory at addresses like 0xF000 0000. I have some problem to access this memory area and I supose it comes from VxWorks cache management system. Indeed, I've been ...

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Thread: high addresses & cache

  1. high addresses & cache

    Hello all,

    I'd like to access PCI memory address space located in memory at addresses
    like 0xF000 0000.

    I have some problem to access this memory area and I supose it comes from
    VxWorks cache management system. Indeed, I've been told by a friend that
    VxWorks uses the MSB of the address to determine if this space if cachable
    or not.

    Is this right?

    If yes, how can I access memory upper than 0x7FFF FFFF?

    Thanks in advance for your answers



  2. Re: high addresses & cache

    Christophe Couturier wrote:
    > Hello all,
    >
    > I'd like to access PCI memory address space located in memory at addresses
    > like 0xF000 0000.
    >
    > I have some problem to access this memory area and I supose it comes from
    > VxWorks cache management system. Indeed, I've been told by a friend that
    > VxWorks uses the MSB of the address to determine if this space if cachable
    > or not.
    >
    > Is this right?
    >
    > If yes, how can I access memory upper than 0x7FFF FFFF?
    >
    > Thanks in advance for your answers
    >
    >


    Hello,

    You should describe your problem.
    Could you also give us more information on the architecture you are
    working: PPC, x86, SH, MIPS, ARM...

    Anyway, make sure that the PCI area you intend to access is available
    and correctly configured in the sysPhysMemDesc[] table (and/or
    sysBatDescTbl[] is the architecture is PPC) in file sysLib.c of your
    BSP. This is needed when you are working with MMU enable.


    Pat

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