why we are adding BAR address to sysPhysMemDesc[] table ? - VxWorks

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Thread: why we are adding BAR address to sysPhysMemDesc[] table ?

  1. why we are adding BAR address to sysPhysMemDesc[] table ?


    Hai all,

    Why we are adding our BAR address to sysPhysMemDesc[] table ?.Can't we
    access those memory with out adding?.


  2. Re: why we are adding BAR address to sysPhysMemDesc[] table ?

    Where would this code be? Is the PCI bus somehow involved?

    I'd guess the answer might be in Wind River "WTN-49".

    lc

    Raja wrote:
    > Hai all,
    >
    > Why we are adding our BAR address to sysPhysMemDesc[] table ?.Can't we
    > access those memory with out adding?.



  3. Re: why we are adding BAR address to sysPhysMemDesc[] table ?

    On 16 Jun 2006, mraja@datapatterns.co.in wrote:

    > Why we are adding our BAR address to sysPhysMemDesc[] table ?.Can't
    > we access those memory with out adding?.


    You have full access to all physical memory before you turn the MMU
    on. After the MMU is turned on, you need to have the BAR mapped.

    Your question is extremely vague. What is a BAR? My guess is the
    "Base Address Register" either on a Motorola embedded chip, like the
    PPC 860 or a 68k 68360, etc. Not to pick on you, as a lot of posters
    seem to offer little information around here lately.

    vxWorks (5.x, another guess as you didn't say what version of vxWorks
    you are using) will turn the MMU on in file usrConfig.c or possibly
    very early if you have a bootable image [romInit.s].

    hth,
    Bill Pringlemeir.

    --
    The birds of leaving call to us. Yet here we stand endowed with the
    fear of flight. - Dead can Dance

    vxWorks FAQ, "http://www.xs4all.nl/~borkhuis/vxworks/vxworks.html"

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