Re: [RFC v1 PATCH 1/2] of/pci: add of_pci_dma_configure() update dma configuration

[Arnd Bergmann]

On Monday 22 December 2014 16:40:43 Murali Karicheri wrote:
> >> +++ b/arch/arm/mm/dma-mapping.c
> >> @@ -2052,9 +2052,10 @@ void arch_setup_dma_ops(struct device *dev, u64
> >> dma_base, u64 size,
> >>                           struct iommu_ops *iommu, bool coherent)
> >>    {
> >>           struct dma_map_ops *dma_ops;
> >> +       u64 temp_size = min((*(dev->dma_mask) + 1), size);
> >>
> >>           dev->archdata.dma_coherent = coherent;
> >> -       if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu))
> >> +       if (arm_setup_iommu_dma_ops(dev, dma_base, temp_size, iommu))
> >>
> >> If you agree, I will post v1 of the patch with these updates. Let me
> >> know. I did some basic tests on Keystone with these changes and it works
> >> fine.
> >
> > It's not exactly what I meant. My main point was that we need to limit
> > dev->dma_mask to (size-1) here, but you are not touching that.
> 
> if you mean overriding the dev->dma_mask to min((*dev->dma_mask), 
> size-1), then I am getting the error "Coherent DMA mask 0x7fffffff (pfn 
> 0x780000-0x800000) covers a smaller range of system memory than the DMA 
> zone pfn 0x0-0x880000) when the devices on Keystone tries to set the dma 
> mask. Something wrong and I need to look into the code.

Right, it sounds like the offset was applied incorrectly at some point.

What are the DMA zone size and the phys-offset?

	Arnd
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