Re: [PATCH v2 0/7] of: setup dma parameters using dma-ranges and dma-coherent

[Rob Herring]

On Sat, Apr 19, 2014 at 9:32 AM, Santosh Shilimkar
<santosh.shilimkar@xxxxxx> wrote:
> Here is an updated version of [2] based on discussion. Series introduces
> support for setting up dma parameters based on device tree properties
> like 'dma-ranges' and 'dma-coherent' and also update to ARM 32 bit port.
> Earlier version of the same series is here [1].
>
> The 'dma-ranges' helps to take care of few DMAable system memory restrictions
> by use of dma_pfn_offset which we maintain now per device. Arch code then
> uses it for dma address translations for such cases. We update the
> dma_pfn_offset accordingly during DT the device creation process.The
> 'dma-coherent' property is used to setup arch's coherent dma_ops.
>
> After some off-list discussion with RMK and Arnd, I have now dropped the
> controversial dma_mask setup code from the series which actually isn't blocking
> me as such. Considering rest of the parts of the series are already aligned,
> am hoping to get this version merged for 3.16 merge window.

Can you briefly describe what the h/w looks like in terms of addresses
for the problem you are trying to solve? Something like: Cpu view of
RAM is X to Y address, X corresponds to DMA address Z. Max DMA address
is ?

Rob
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