[patch 1/1] powerpc: enable ARCH_DMA_ADDR_T_64BIT with ARCH_PHYS_ADDR_T_64BIT

[Josh Boyer]

On Fri, Oct 1, 2010 at 5:12 PM,  <akpm at linux-foundation.org> wrote:
> From: FUJITA Tomonori <fujita.tomonori at lab.ntt.co.jp>
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori at lab.ntt.co.jp>
> Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> ---
>
>  arch/powerpc/Kconfig |    3 +++
>  1 file changed, 3 insertions(+)
>
> diff -puN arch/powerpc/Kconfig~powerpc-enable-arch_dma_addr_t_64bit-with-arch_phys_addr_t_64bit arch/powerpc/Kconfig
> --- a/arch/powerpc/Kconfig~powerpc-enable-arch_dma_addr_t_64bit-with-arch_phys_addr_t_64bit
> +++ a/arch/powerpc/Kconfig
> @@ -16,6 +16,9 @@ config WORD_SIZE
>  config ARCH_PHYS_ADDR_T_64BIT
>        def_bool PPC64 || PHYS_64BIT
>
> +config ARCH_DMA_ADDR_T_64BIT
> +       def_bool ARCH_PHYS_ADDR_T_64BIT
> +

I seemed to have missed what this is about entirely.  Is there some
place I can look that describes what that is supposed to do?  The PPC
4xx boards set PHYS_ADDR_T_64BIT because the MMU uses 36 bit
addressing, but the CPU is only 32 bits.  I want to make sure this DMA
thing isn't going to cause problems.

josh