dma-mapping: export new dma_*map_phys() interface

Introduce new DMA mapping functions dma_map_phys() and dma_unmap_phys()
that operate directly on physical addresses instead of page+offset
parameters. This provides a more efficient interface for drivers that
already have physical addresses available.

The new functions are implemented as the primary mapping layer, with
the existing dma_map_page_attrs()/dma_map_resource() and
dma_unmap_page_attrs()/dma_unmap_resource() functions converted to simple
wrappers around the phys-based implementations.

In case dma_map_page_attrs(), the struct page is converted to physical
address with help of page_to_phys() function and dma_map_resource()
provides physical address as is together with addition of DMA_ATTR_MMIO
attribute.

The old page-based API is preserved in mapping.c to ensure that existing
code won't be affected by changing EXPORT_SYMBOL to EXPORT_SYMBOL_GPL
variant for dma_*map_phys().

Reviewed-by: Jason Gunthorpe <[e-mail]>
Reviewed-by: Keith Busch <[e-mail]>
Signed-off-by: Leon Romanovsky <[e-mail]>
Signed-off-by: Marek Szyprowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/iommu/dma-iommu.c

···
 		__iommu_dma_unmap(dev, start, end - start);
 }
 
-dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
-		size_t size, enum dma_data_direction dir, unsigned long attrs)
-{
-	return __iommu_dma_map(dev, phys, size,
-			dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO,
-			dma_get_mask(dev));
-}
-
-void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir, unsigned long attrs)
-{
-	__iommu_dma_unmap(dev, handle, size);
-}
-
 static void __iommu_dma_free(struct device *dev, size_t size, void *cpu_addr)
 {
 	size_t alloc_size = PAGE_ALIGN(size);

include/linux/dma-direct.h

···
 		struct page *page, dma_addr_t dma_addr,
 		enum dma_data_direction dir);
 int dma_direct_supported(struct device *dev, u64 mask);
-dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
-		size_t size, enum dma_data_direction dir, unsigned long attrs);
 
 #endif /* _LINUX_DMA_DIRECT_H */

include/linux/dma-mapping.h

···
 		unsigned long attrs);
 void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
 		enum dma_data_direction dir, unsigned long attrs);
+dma_addr_t dma_map_phys(struct device *dev, phys_addr_t phys, size_t size,
+		enum dma_data_direction dir, unsigned long attrs);
+void dma_unmap_phys(struct device *dev, dma_addr_t addr, size_t size,
+		enum dma_data_direction dir, unsigned long attrs);
 unsigned int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
 		int nents, enum dma_data_direction dir, unsigned long attrs);
 void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
···
 	return DMA_MAPPING_ERROR;
 }
 static inline void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+}
+static inline dma_addr_t dma_map_phys(struct device *dev, phys_addr_t phys,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	return DMA_MAPPING_ERROR;
+}
+static inline void dma_unmap_phys(struct device *dev, dma_addr_t addr,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
 }

include/linux/iommu-dma.h

···
 size_t iommu_dma_max_mapping_size(struct device *dev);
 void iommu_dma_free(struct device *dev, size_t size, void *cpu_addr,
 		dma_addr_t handle, unsigned long attrs);
-dma_addr_t iommu_dma_map_resource(struct device *dev, phys_addr_t phys,
-		size_t size, enum dma_data_direction dir, unsigned long attrs);
-void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir, unsigned long attrs);
 struct sg_table *iommu_dma_alloc_noncontiguous(struct device *dev, size_t size,
 		enum dma_data_direction dir, gfp_t gfp, unsigned long attrs);
 void iommu_dma_free_noncontiguous(struct device *dev, size_t size,

include/trace/events/dma.h

···
 	TP_ARGS(dev, phys_addr, dma_addr, size, dir, attrs))
 
 DEFINE_MAP_EVENT(dma_map_phys);
-DEFINE_MAP_EVENT(dma_map_resource);
 
 DECLARE_EVENT_CLASS(dma_unmap,
 	TP_PROTO(struct device *dev, dma_addr_t addr, size_t size,
···
 	TP_ARGS(dev, addr, size, dir, attrs))
 
 DEFINE_UNMAP_EVENT(dma_unmap_phys);
-DEFINE_UNMAP_EVENT(dma_unmap_resource);
 
 DECLARE_EVENT_CLASS(dma_alloc_class,
 	TP_PROTO(struct device *dev, void *virt_addr, dma_addr_t dma_addr,

kernel/dma/debug.c

···
 	dma_debug_single,
 	dma_debug_sg,
 	dma_debug_coherent,
-	dma_debug_resource,
 	dma_debug_noncoherent,
 	dma_debug_phy,
 };
···
 	[dma_debug_single] = "single",
 	[dma_debug_sg] = "scatter-gather",
 	[dma_debug_coherent] = "coherent",
-	[dma_debug_resource] = "resource",
 	[dma_debug_noncoherent] = "noncoherent",
 	[dma_debug_phy] = "phy",
 };
···
 		return;
 
 	ref.paddr = virt_to_paddr(virt);
-
-	if (unlikely(dma_debug_disabled()))
-		return;
-
-	check_unmap(&ref);
-}
-
-void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
-			    int direction, dma_addr_t dma_addr,
-			    unsigned long attrs)
-{
-	struct dma_debug_entry *entry;
-
-	if (unlikely(dma_debug_disabled()))
-		return;
-
-	entry = dma_entry_alloc();
-	if (!entry)
-		return;
-
-	entry->type		= dma_debug_resource;
-	entry->dev		= dev;
-	entry->paddr		= addr;
-	entry->size		= size;
-	entry->dev_addr		= dma_addr;
-	entry->direction	= direction;
-	entry->map_err_type	= MAP_ERR_NOT_CHECKED;
-
-	add_dma_entry(entry, attrs);
-}
-
-void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
-			      size_t size, int direction)
-{
-	struct dma_debug_entry ref = {
-		.type           = dma_debug_resource,
-		.dev            = dev,
-		.dev_addr       = dma_addr,
-		.size           = size,
-		.direction      = direction,
-	};
 
 	if (unlikely(dma_debug_disabled()))
 		return;

kernel/dma/debug.h

···
 extern void debug_dma_free_coherent(struct device *dev, size_t size,
 				    void *virt, dma_addr_t addr);
 
-extern void debug_dma_map_resource(struct device *dev, phys_addr_t addr,
-				   size_t size, int direction,
-				   dma_addr_t dma_addr,
-				   unsigned long attrs);
-
-extern void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
-				     size_t size, int direction);
-
 extern void debug_dma_sync_single_for_cpu(struct device *dev,
 					  dma_addr_t dma_handle, size_t size,
 					  int direction);
···
 
 static inline void debug_dma_free_coherent(struct device *dev, size_t size,
 					   void *virt, dma_addr_t addr)
-{
-}
-
-static inline void debug_dma_map_resource(struct device *dev, phys_addr_t addr,
-					  size_t size, int direction,
-					  dma_addr_t dma_addr,
-					  unsigned long attrs)
-{
-}
-
-static inline void debug_dma_unmap_resource(struct device *dev,
-					    dma_addr_t dma_addr, size_t size,
-					    int direction)
 {
 }
 

kernel/dma/direct.c

···
 	return ret;
 }
 
-dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
-		size_t size, enum dma_data_direction dir, unsigned long attrs)
-{
-	dma_addr_t dma_addr = paddr;
-
-	if (unlikely(!dma_capable(dev, dma_addr, size, false))) {
-		dev_err_once(dev,
-			     "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
-			     &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
-		WARN_ON_ONCE(1);
-		return DMA_MAPPING_ERROR;
-	}
-
-	return dma_addr;
-}
-
 int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
 		void *cpu_addr, dma_addr_t dma_addr, size_t size,
 		unsigned long attrs)

kernel/dma/mapping.c

···
 	return dma_go_direct(dev, *dev->dma_mask, ops);
 }
 
-dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
-		size_t offset, size_t size, enum dma_data_direction dir,
-		unsigned long attrs)
+dma_addr_t dma_map_phys(struct device *dev, phys_addr_t phys, size_t size,
+		enum dma_data_direction dir, unsigned long attrs)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
-	phys_addr_t phys = page_to_phys(page) + offset;
 	bool is_mmio = attrs & DMA_ATTR_MMIO;
 	dma_addr_t addr;
 
···
 
 		addr = ops->map_resource(dev, phys, size, dir, attrs);
 	} else {
+		struct page *page = phys_to_page(phys);
+		size_t offset = offset_in_page(phys);
+
 		/*
 		 * The dma_ops API contract for ops->map_page() requires
 		 * kmappable memory, while ops->map_resource() does not.
···
 
 	return addr;
 }
+EXPORT_SYMBOL_GPL(dma_map_phys);
+
+dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page,
+		size_t offset, size_t size, enum dma_data_direction dir,
+		unsigned long attrs)
+{
+	phys_addr_t phys = page_to_phys(page) + offset;
+
+	if (unlikely(attrs & DMA_ATTR_MMIO))
+		return DMA_MAPPING_ERROR;
+
+	if (IS_ENABLED(CONFIG_DMA_API_DEBUG) &&
+	    WARN_ON_ONCE(is_zone_device_page(page)))
+		return DMA_MAPPING_ERROR;
+
+	return dma_map_phys(dev, phys, size, dir, attrs);
+}
 EXPORT_SYMBOL(dma_map_page_attrs);
 
-void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
+void dma_unmap_phys(struct device *dev, dma_addr_t addr, size_t size,
 		enum dma_data_direction dir, unsigned long attrs)
 {
 	const struct dma_map_ops *ops = get_dma_ops(dev);
···
 		ops->unmap_page(dev, addr, size, dir, attrs);
 	trace_dma_unmap_phys(dev, addr, size, dir, attrs);
 	debug_dma_unmap_phys(dev, addr, size, dir);
+}
+EXPORT_SYMBOL_GPL(dma_unmap_phys);
+
+void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr, size_t size,
+		 enum dma_data_direction dir, unsigned long attrs)
+{
+	if (unlikely(attrs & DMA_ATTR_MMIO))
+		return;
+
+	dma_unmap_phys(dev, addr, size, dir, attrs);
 }
 EXPORT_SYMBOL(dma_unmap_page_attrs);
 
···
 dma_addr_t dma_map_resource(struct device *dev, phys_addr_t phys_addr,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-	dma_addr_t addr = DMA_MAPPING_ERROR;
-
-	BUG_ON(!valid_dma_direction(dir));
-
-	if (WARN_ON_ONCE(!dev->dma_mask))
+	if (IS_ENABLED(CONFIG_DMA_API_DEBUG) &&
+	    WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
 		return DMA_MAPPING_ERROR;
 
-	if (dma_map_direct(dev, ops))
-		addr = dma_direct_map_resource(dev, phys_addr, size, dir, attrs);
-	else if (use_dma_iommu(dev))
-		addr = iommu_dma_map_resource(dev, phys_addr, size, dir, attrs);
-	else if (ops->map_resource)
-		addr = ops->map_resource(dev, phys_addr, size, dir, attrs);
-
-	trace_dma_map_resource(dev, phys_addr, addr, size, dir, attrs);
-	debug_dma_map_resource(dev, phys_addr, size, dir, addr, attrs);
-	return addr;
+	return dma_map_phys(dev, phys_addr, size, dir, attrs | DMA_ATTR_MMIO);
 }
 EXPORT_SYMBOL(dma_map_resource);
 
 void dma_unmap_resource(struct device *dev, dma_addr_t addr, size_t size,
 		enum dma_data_direction dir, unsigned long attrs)
 {
-	const struct dma_map_ops *ops = get_dma_ops(dev);
-
-	BUG_ON(!valid_dma_direction(dir));
-	if (dma_map_direct(dev, ops))
-		; /* nothing to do: uncached and no swiotlb */
-	else if (use_dma_iommu(dev))
-		iommu_dma_unmap_resource(dev, addr, size, dir, attrs);
-	else if (ops->unmap_resource)
-		ops->unmap_resource(dev, addr, size, dir, attrs);
-	trace_dma_unmap_resource(dev, addr, size, dir, attrs);
-	debug_dma_unmap_resource(dev, addr, size, dir);
+	dma_unmap_phys(dev, addr, size, dir, attrs | DMA_ATTR_MMIO);
 }
 EXPORT_SYMBOL(dma_unmap_resource);