The dma_sync_* operations are now the only difference between the
coherent and non-coherent IOMMU ops. Some minor tweaks to make those
safe for coherent devices with minimal overhead, and we can condense
down to a single set of DMA ops.

Signed-off-by: Robin Murphy <robin.mur...@arm.com>
---
 arch/arm/mm/dma-mapping.c | 41 +++++++++++++--------------------------
 1 file changed, 13 insertions(+), 28 deletions(-)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 1bb7e9608f75..0537c97cebe1 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1677,6 +1677,9 @@ static void arm_iommu_sync_sg_for_cpu(struct device *dev,
        struct scatterlist *s;
        int i;
 
+       if (dev->dma_coherent)
+               return;
+
        for_each_sg(sg, s, nents, i)
                __dma_page_dev_to_cpu(sg_page(s), s->offset, s->length, dir);
 
@@ -1696,6 +1699,9 @@ static void arm_iommu_sync_sg_for_device(struct device 
*dev,
        struct scatterlist *s;
        int i;
 
+       if (dev->dma_coherent)
+               return;
+
        for_each_sg(sg, s, nents, i)
                __dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir);
 }
@@ -1829,12 +1835,13 @@ static void arm_iommu_sync_single_for_cpu(struct device 
*dev,
 {
        struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
        dma_addr_t iova = handle & PAGE_MASK;
-       struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, 
iova));
+       struct page *page;
        unsigned int offset = handle & ~PAGE_MASK;
 
-       if (!iova)
+       if (dev->dma_coherent || !iova)
                return;
 
+       page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
        __dma_page_dev_to_cpu(page, offset, size, dir);
 }
 
@@ -1843,12 +1850,13 @@ static void arm_iommu_sync_single_for_device(struct 
device *dev,
 {
        struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
        dma_addr_t iova = handle & PAGE_MASK;
-       struct page *page = phys_to_page(iommu_iova_to_phys(mapping->domain, 
iova));
+       struct page *page;
        unsigned int offset = handle & ~PAGE_MASK;
 
-       if (!iova)
+       if (dev->dma_coherent || !iova)
                return;
 
+       page = phys_to_page(iommu_iova_to_phys(mapping->domain, iova));
        __dma_page_cpu_to_dev(page, offset, size, dir);
 }
 
@@ -1872,22 +1880,6 @@ static const struct dma_map_ops iommu_ops = {
        .unmap_resource         = arm_iommu_unmap_resource,
 };
 
-static const struct dma_map_ops iommu_coherent_ops = {
-       .alloc          = arm_iommu_alloc_attrs,
-       .free           = arm_iommu_free_attrs,
-       .mmap           = arm_iommu_mmap_attrs,
-       .get_sgtable    = arm_iommu_get_sgtable,
-
-       .map_page       = arm_iommu_map_page,
-       .unmap_page     = arm_iommu_unmap_page,
-
-       .map_sg         = arm_iommu_map_sg,
-       .unmap_sg       = arm_iommu_unmap_sg,
-
-       .map_resource   = arm_iommu_map_resource,
-       .unmap_resource = arm_iommu_unmap_resource,
-};
-
 /**
  * arm_iommu_create_mapping
  * @bus: pointer to the bus holding the client device (for IOMMU calls)
@@ -2067,11 +2059,6 @@ void arm_iommu_detach_device(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(arm_iommu_detach_device);
 
-static const struct dma_map_ops *arm_get_iommu_dma_map_ops(bool coherent)
-{
-       return coherent ? &iommu_coherent_ops : &iommu_ops;
-}
-
 static bool arm_setup_iommu_dma_ops(struct device *dev, u64 dma_base, u64 size,
                                    const struct iommu_ops *iommu)
 {
@@ -2118,8 +2105,6 @@ static bool arm_setup_iommu_dma_ops(struct device *dev, 
u64 dma_base, u64 size,
 
 static void arm_teardown_iommu_dma_ops(struct device *dev) { }
 
-#define arm_get_iommu_dma_map_ops arm_get_dma_map_ops
-
 #endif /* CONFIG_ARM_DMA_USE_IOMMU */
 
 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
@@ -2141,7 +2126,7 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, 
u64 size,
                return;
 
        if (arm_setup_iommu_dma_ops(dev, dma_base, size, iommu))
-               dma_ops = arm_get_iommu_dma_map_ops(coherent);
+               dma_ops = &iommu_ops;
        else
                dma_ops = arm_get_dma_map_ops(coherent);
 
-- 
2.28.0.dirty

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