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Subject[PATCH v3 4/8] arm: dma-mapping: add {map,unmap}_resource for iommu ops
Date
Add methods to map/unmap device resources addresses for dma_map_ops that
are IOMMU aware. This is needed to map a device MMIO register from a
physical address.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
---
arch/arm/mm/dma-mapping.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 63 insertions(+)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 0eca381..ae2b175 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1814,6 +1814,63 @@ static void arm_iommu_unmap_page(struct device *dev, dma_addr_t handle,
__free_iova(mapping, iova, len);
}

+/**
+ * arm_iommu_map_resource - map a device resource for DMA
+ * @dev: valid struct device pointer
+ * @phys_addr: physical address of resource
+ * @size: size of resource to map
+ * @dir: DMA transfer direction
+ */
+static dma_addr_t arm_iommu_map_resource(struct device *dev,
+ phys_addr_t phys_addr, size_t size,
+ enum dma_data_direction dir, struct dma_attrs *attrs)
+{
+ struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ dma_addr_t dma_addr;
+ int ret, prot;
+ phys_addr_t addr = phys_addr & PAGE_MASK;
+ int offset = phys_addr & ~PAGE_MASK;
+ int len = PAGE_ALIGN(size + offset);
+
+ dma_addr = __alloc_iova(mapping, size);
+ if (dma_addr == DMA_ERROR_CODE)
+ return dma_addr;
+
+ prot = __dma_direction_to_prot(dir) | IOMMU_MMIO;
+
+ ret = iommu_map(mapping->domain, dma_addr, addr, len, prot);
+ if (ret < 0)
+ goto fail;
+
+ return dma_addr + offset;
+fail:
+ __free_iova(mapping, dma_addr, size);
+ return DMA_ERROR_CODE;
+}
+
+/**
+ * arm_iommu_unmap_resource - unmap a device DMA resource
+ * @dev: valid struct device pointer
+ * @dma_handle: DMA address to resource
+ * @size: size of resource to map
+ * @dir: DMA transfer direction
+ */
+static void arm_iommu_unmap_resource(struct device *dev, dma_addr_t dma_handle,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
+ dma_addr_t iova = dma_handle & PAGE_MASK;
+ int offset = dma_handle & ~PAGE_MASK;
+ int len = PAGE_ALIGN(size + offset);
+
+ if (!iova)
+ return;
+
+ iommu_unmap(mapping->domain, iova, len);
+ __free_iova(mapping, iova, len);
+}
+
static void arm_iommu_sync_single_for_cpu(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
@@ -1858,6 +1915,9 @@ struct dma_map_ops iommu_ops = {
.sync_sg_for_cpu = arm_iommu_sync_sg_for_cpu,
.sync_sg_for_device = arm_iommu_sync_sg_for_device,

+ .map_resource = arm_iommu_map_resource,
+ .unmap_resource = arm_iommu_unmap_resource,
+
.set_dma_mask = arm_dma_set_mask,
};

@@ -1873,6 +1933,9 @@ struct dma_map_ops iommu_coherent_ops = {
.map_sg = arm_coherent_iommu_map_sg,
.unmap_sg = arm_coherent_iommu_unmap_sg,

+ .map_resource = arm_iommu_map_resource,
+ .unmap_resource = arm_iommu_unmap_resource,
+
.set_dma_mask = arm_dma_set_mask,
};

--
2.7.1
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