On Fri, 2021-05-21 at 16:06 +0800, Tzung-Bi Shih wrote: > On Fri, May 21, 2021 at 3:02 PM Irui Wang <irui.wang@xxxxxxxxxxxx> wrote: > > + if (of_get_property(pdev->dev.of_node, "dma-ranges", NULL)) > > + dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(34)); > > + > > From your previous dt-bindings patch[1], it has 4 banks. > > 0~4G; 4G~8G; 8G~12G; 12G~16G. > > But, the code treats it as a boolean. I.e. 0~4GB if non-existent; > otherwise, 4GB~8GB. Here DMA_BIT_MASK(34) means dma address support 34bits(16GB). The code is ok for me. Only the commit message should not say 4G-8G. it could be something like: Use the dma_set_mask_and_coherent helper to set venc DMA bit mask to support 34bits iova space(16GB) that the mt8192 iommu HW support. Whole the iova range separate to 0~4G/4G~8G/8G~12G/12G~16G, Regarding which iova range VENC actually locate, it depend on the dma-ranges property of the venc dtsi node. > > [1]: https://patchwork.linuxtv.org/project/linux-media/patch/20210521070139.20644-3-irui.wang@xxxxxxxxxxxx/ > > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-mediatek
