Hi Yong Wu, On Thu, Jul 16, 2015 at 10:04:34AM +0100, Yong Wu wrote: > This patch adds support for mediatek m4u (MultiMedia Memory Management > Unit). [...] > +static void mtk_iommu_tlb_flush_all(void *cookie) > +{ > + struct mtk_iommu_domain *domain = cookie; > + void __iomem *base; > + > + base = domain->data->base; > + writel(F_INVLD_EN1 | F_INVLD_EN0, base + REG_MMU_INV_SEL); > + writel(F_ALL_INVLD, base + REG_MMU_INVALIDATE); This needs to be synchronous, so you probably want to call mtk_iommu_tlb_sync at the end. > +} > + > +static void mtk_iommu_tlb_add_flush(unsigned long iova, size_t size, > + bool leaf, void *cookie) > +{ > + struct mtk_iommu_domain *domain = cookie; > + void __iomem *base = domain->data->base; > + unsigned int iova_start = iova, iova_end = iova + size - 1; > + > + writel(F_INVLD_EN1 | F_INVLD_EN0, base + REG_MMU_INV_SEL); > + > + writel(iova_start, base + REG_MMU_INVLD_START_A); > + writel(iova_end, base + REG_MMU_INVLD_END_A); > + writel(F_MMU_INV_RANGE, base + REG_MMU_INVALIDATE); Why are you using writel instead of writel_relaxed? I asked this before but I don't think you replied. Will -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html