[PATCH v2 5/6] iommu/mediatek: Add mt8173 IOMMU driver
From: Will Deacon <hidden>
Date: 2015-06-05 13:30:49
Also in:
linux-devicetree, linux-iommu, linux-mediatek, lkml
On Fri, May 15, 2015 at 10:43:28AM +0100, Yong Wu wrote:
This patch adds support for mediatek m4u (MultiMedia Memory Management Unit).
After looking at the page table code, I thought I'd come and check your TLB invalidate code here.
quoted hunk ↗ jump to hunk
+static void mtk_iommu_tlb_flush_all(void *cookie) +{ + struct mtk_iommu_domain *domain = cookie; + u32 val; + + val = F_INVLD_EN1 | F_INVLD_EN0; + writel(val, domain->imuinfo->base + REG_MMU_INV_SEL); + writel(F_ALL_INVLD, domain->imuinfo->base + REG_MMU_INVALIDATE); +} + +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 *m4u_base = domain->imuinfo->base; + unsigned int iova_start = iova, iova_end = iova + size - 1; + int ret; + u32 val; + + val = F_INVLD_EN1 | F_INVLD_EN0; + writel(val, m4u_base + REG_MMU_INV_SEL); + + writel(iova_start, m4u_base + REG_MMU_INVLD_START_A); + writel(iova_end, m4u_base + REG_MMU_INVLD_END_A); + writel(F_MMU_INV_RANGE, m4u_base + REG_MMU_INVALIDATE); + + ret = readl_poll_timeout_atomic(m4u_base + REG_MMU_CPE_DONE, val, + val != 0, 10, 1000000); + if (ret) { + dev_warn(domain->imuinfo->dev, "Invalid tlb don't done\n"); + mtk_iommu_tlb_flush_all(cookie); + } + writel(0, m4u_base + REG_MMU_CPE_DONE); +}
You don't need to wait for completion here if you can implement a proper ->tlb_sync callback.
quoted hunk ↗ jump to hunk
+static void mtk_iommu_flush_pgtable(void *ptr, size_t size, void *cookie) +{ + /* + * After delete arch_setup_dma_ops, + * This will be replaced with dma_map_page + */ + __dma_flush_range(ptr, ptr + size); +}
This should give you the necessary barriers to ensure visibility of the updated page tables, so you can use the _relaxed io accessors for the other TLB functions.
quoted hunk ↗ jump to hunk
+static struct iommu_gather_ops mtk_iommu_gather_ops = { + .tlb_flush_all = mtk_iommu_tlb_flush_all, + .tlb_add_flush = mtk_iommu_tlb_add_flush, + .tlb_sync = mtk_iommu_tlb_flush_all,
sync isn't required to flush anything; it's just supposed to wait for any outstanding invalidation (i.e. from tlb_add_flush) to complete. Will