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    Subjectgeneric page.h problem
    I'm working with a new architecture port (nommu) and was wanting to use
    the generic page.h but there is a problem. I'm using CONFIG_FLATMEM with
    a non-zero CONFIG_KERNEL_RAM_BASE_ADDRESS. The hardware uses this same
    address to access RAM from code and for DMA purposes. The generic page.h

    #define PAGE_OFFSET (0)

    #ifndef __ASSEMBLY__

    #define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
    #define __pa(x) ((unsigned long) (x) - PAGE_OFFSET)

    The problem I have is that __va(x) and __pa(x) should do nothing on
    this architecture. If I use the following, then everything seems to
    work as it should.

    diff --git a/include/asm-generic/page.h b/include/asm-generic/page.h
    index 75fec18..4dc4a81 100644
    --- a/include/asm-generic/page.h
    +++ b/include/asm-generic/page.h
    @@ -73,8 +73,8 @@ extern unsigned long memory_end;

    #ifndef __ASSEMBLY__

    -#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
    -#define __pa(x) ((unsigned long) (x) - PAGE_OFFSET)
    +#define __va(x) ((void *)((unsigned long) (x)))
    +#define __pa(x) ((unsigned long) (x))

    #define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
    #define pfn_to_virt(pfn) __va((pfn) << PAGE_SHIFT)

    Am I missing something here? The only other arch using the generic
    page.h is blackfin, but it uses a zero PAGE_OFFSET, so my patch
    would have no effect there.


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      Last update: 2011-03-23 20:15    [W:0.019 / U:13.340 seconds]
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