[PATCH v1 06/16] iommu/dma: extend iommu_dma_*map_phys API to handle MMIO memory

Leon Romanovsky leon at kernel.org
Mon Aug 4 22:42:40 AEST 2025


From: Leon Romanovsky <leonro at nvidia.com>

Combine iommu_dma_*map_phys with iommu_dma_*map_resource interfaces in
order to allow single phys_addr_t flow.

Signed-off-by: Leon Romanovsky <leonro at nvidia.com>
---
 drivers/iommu/dma-iommu.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 11c5d5f8c0981..0a19ce50938b3 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1193,12 +1193,17 @@ static inline size_t iova_unaligned(struct iova_domain *iovad, phys_addr_t phys,
 dma_addr_t iommu_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size,
 		enum dma_data_direction dir, unsigned long attrs)
 {
-	bool coherent = dev_is_dma_coherent(dev);
-	int prot = dma_info_to_prot(dir, coherent, attrs);
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	struct iova_domain *iovad = &cookie->iovad;
 	dma_addr_t iova, dma_mask = dma_get_mask(dev);
+	bool coherent;
+	int prot;
+
+	if (attrs & DMA_ATTR_MMIO)
+		return __iommu_dma_map(dev, phys, size,
+				dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO,
+				dma_get_mask(dev));
 
 	/*
 	 * If both the physical buffer start address and size are page aligned,
@@ -1211,6 +1216,9 @@ dma_addr_t iommu_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size,
 			return DMA_MAPPING_ERROR;
 	}
 
+	coherent = dev_is_dma_coherent(dev);
+	prot = dma_info_to_prot(dir, coherent, attrs);
+
 	if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		arch_sync_dma_for_device(phys, size, dir);
 
@@ -1223,10 +1231,14 @@ dma_addr_t iommu_dma_map_phys(struct device *dev, phys_addr_t phys, size_t size,
 void iommu_dma_unmap_phys(struct device *dev, dma_addr_t dma_handle,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
-	struct iommu_domain *domain = iommu_get_dma_domain(dev);
 	phys_addr_t phys;
 
-	phys = iommu_iova_to_phys(domain, dma_handle);
+	if (attrs & DMA_ATTR_MMIO) {
+		__iommu_dma_unmap(dev, dma_handle, size);
+		return;
+	}
+
+	phys = iommu_iova_to_phys(iommu_get_dma_domain(dev), dma_handle);
 	if (WARN_ON(!phys))
 		return;
 
-- 
2.50.1



More information about the Linuxppc-dev mailing list