Hi, Arnd Bergmann <arnd@xxxxxxxx> writes: [...] > Regarding the DMA configuration that you mention in ci_hdrc_add_device(), > I think we should replace > > pdev->dev.dma_mask = dev->dma_mask; > pdev->dev.dma_parms = dev->dma_parms; > dma_set_coherent_mask(&pdev->dev, dev->coherent_dma_mask); > > with of_dma_configure(), which has the chance to configure more than > just those three, as the dma API might look into different aspects: > > - iommu specific configuration > - cache coherency information > - bus type > - dma offset > - dma_map_ops pointer > > We try to handle everything in of_dma_configure() at configuration > time, and that would be the place to add anything else that we might > need in the future. There are a couple problems with this: 1) won't work for PCI-based systems. DWC3 is used in production PCI-based HW and also in Synopsys HAPS DX platform (FPGA that appears like a PCI card to host PC) 2) not very robust solution of_dma_configure() will hardcode 32-bit DMA dmask for xhci-plat because that's not created by DT. The only reason why this works at all is because of the default 32-bit dma mask thing :-) So, how is it any different than copying 32-bit dma mask from parent? -- balbi
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