How to define sysMemTop and sysPhysMemTop for 2 discontinous RAM - VxWorks

This is a discussion on How to define sysMemTop and sysPhysMemTop for 2 discontinous RAM - VxWorks ; Hi, We are using MPC8572 processor. We are actually porting the system from older processor to new 1. We are using 2GB of SDRAM which we cannot map continuously. 1st RAM map : 0x0 to 1GB 2nd RAM map : ...

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Thread: How to define sysMemTop and sysPhysMemTop for 2 discontinous RAM

  1. How to define sysMemTop and sysPhysMemTop for 2 discontinous RAM

    Hi,

    We are using MPC8572 processor. We are actually porting the system
    from older processor to new 1. We are using 2GB of SDRAM which we
    cannot map continuously.

    1st RAM map : 0x0 to 1GB
    2nd RAM map : 0x8000 0000 to 0xC000 0000.

    How can define my sysMemTop and sysPhysMemTop. How to handle this
    mapping.

    Thanks and Regards,
    Tyler

  2. Re: How to define sysMemTop and sysPhysMemTop for 2 discontinous RAM

    On Jun 9, 6:29*pm, sundar.c...@gmail.com wrote:
    > Hi,
    >
    > * We are usingMPC8572processor. We are actually porting the system
    > from older processor to new 1. We are using 2GB of SDRAM which we
    > cannot map continuously.
    >
    > 1st RAM map : 0x0 to 1GB
    > 2nd RAM map : 0x8000 0000 to 0xC000 0000.
    >
    > How can define my sysMemTop and sysPhysMemTop. How to handle this
    > mapping.
    >
    > Thanks and Regards,
    > Tyler


    ????

  3. Re: How to define sysMemTop and sysPhysMemTop for 2 discontinous RAM

    Hello,

    I may be wrong here so take my advice with a grain of salt.

    If I am not mistaken at boot time VxWorks can handle only contiguous
    physical memory for its text and data/bss segments as well as for its
    heap. So this is what your first bank of RAM should be for. The second
    bank of RAM can be used in the system but you'll have to use the
    memAddToPool() API to get it added to the system's heap.

    Of course, the second bank of RAM must be described in your BSP's
    'sysPhysMemDesc' array.

    Hope this helps,

    --
    PAD

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