On 7 June 2016 at 16:43, Arnd Bergmann <[email protected]> wrote: > On Tuesday, June 7, 2016 4:29:21 PM CEST Baolin Wang wrote: >> Now on ARM64 platform, it will set 'dummy_dma_ops' for device dma_ops if >> it did not call 'arch_setup_dma_ops' at device creation time by issuing >> platform_device_alloc() function, that will cause failure when setting >> the dma mask for device. >> >> Hence We need to hook the archdata to setup proper dma_ops for these devices. >> >> Signed-off-by: Baolin Wang <[email protected]> >> --- >> arch/arm64/mm/dma-mapping.c | 21 +++++++++++++++++++++ >> 1 file changed, 21 insertions(+) >> >> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c >> index c566ec8..04e057b 100644 >> --- a/arch/arm64/mm/dma-mapping.c >> +++ b/arch/arm64/mm/dma-mapping.c >> @@ -26,6 +26,7 @@ >> #include <linux/dma-contiguous.h> >> #include <linux/vmalloc.h> >> #include <linux/swiotlb.h> >> +#include <linux/platform_device.h> >> >> #include <asm/cacheflush.h> >> >> @@ -961,3 +962,23 @@ void arch_setup_dma_ops(struct device *dev, u64 >> dma_base, u64 size, >> dev->archdata.dma_coherent = coherent; >> __iommu_setup_dma_ops(dev, dma_base, size, iommu); >> } >> + >> +void arch_setup_pdev_archdata(struct platform_device *pdev) >> +{ >> + if (!pdev->dev.archdata.dma_ops) >> + pdev->dev.archdata.dma_ops = &swiotlb_dma_ops; > > You need to check the DT here to see if these are the right ops, > or if you have to go through an IOMMU. Also, you have to set up the > other fields that are controlled by arch_setup_dma_ops: whether > it's coherent and what the offset is.
That's right. This is just set the platform device arch data, after that the dma ops will be re-setup by issuing arch_setup_dma_ops(). But some platform devices created by platform_device_alloc() will not issue the arch_setup_dma_ops() function to setup the dma ops. So I want to set the default dma ops by arch_setup_pdev_archdata(), but that is not reasonable according to Robin's explanation. > >> + /* >> + * Set default coherent_dma_mask to 32 bit. Drivers are expected to >> + * setup the correct supported mask. >> + */ >> + if (!pdev->dev.coherent_dma_mask) >> + pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); >> + >> + /* >> + * Set it to coherent_dma_mask by default if the architecture >> + * code has not set it. >> + */ >> + if (!pdev->dev.dma_mask) >> + pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; >> +} > > We still have an open bug about the dma_set_mask() function on ARM64: > we have to check the dma-ranges property to ensure that no device can > set a mask wider than what its parent bus can support. > > What is your plan for this in case of these devices? I think these are just default setup for dma mask. I suppose the checking you mentioned should be added in of_dma_configure()? -- Baolin.wang Best Regards
