[PATCH 16/18] dma-mapping: add new {alloc,free}_noncoherent dma_map_ops methods

[Christoph Hellwig <hch@lst.de>]

This will allow IOMMU drivers to allocate non-contigous memory and
return a vmapped virtual address.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 include/linux/dma-mapping.h |  5 +++++
 kernel/dma/mapping.c        | 33 +++++++++++++++++++++++++++------
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index bf592cf0db4acb..b4b5d75260d6dc 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -80,6 +80,11 @@ struct dma_map_ops {
 			gfp_t gfp);
 	void (*free_pages)(struct device *dev, size_t size, struct page *vaddr,
 			dma_addr_t dma_handle, enum dma_data_direction dir);
+	void* (*alloc_noncoherent)(struct device *dev, size_t size,
+			dma_addr_t *dma_handle, enum dma_data_direction dir,
+			gfp_t gfp);
+	void (*free_noncoherent)(struct device *dev, size_t size, void *vaddr,
+			dma_addr_t dma_handle, enum dma_data_direction dir);
 	int (*mmap)(struct device *, struct vm_area_struct *,
 			  void *, dma_addr_t, size_t,
 			  unsigned long attrs);
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 6f86c925b8251d..8614d7d2ee59a9 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -502,19 +502,40 @@ EXPORT_SYMBOL_GPL(dma_free_pages);
 void *dma_alloc_noncoherent(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
 {
-	struct page *page;
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+	void *vaddr;
 
-	page = dma_alloc_pages(dev, size, dma_handle, dir, gfp);
-	if (!page)
-		return NULL;
-	return page_address(page);
+	if (!ops || !ops->alloc_noncoherent) {
+		struct page *page;
+
+		page = dma_alloc_pages(dev, size, dma_handle, dir, gfp);
+		if (!page)
+			return NULL;
+		return page_address(page);
+	}
+
+	size = PAGE_ALIGN(size);
+	vaddr = ops->alloc_noncoherent(dev, size, dma_handle, dir, gfp);
+	if (vaddr)
+		debug_dma_map_page(dev, virt_to_page(vaddr), 0, size, dir,
+				   *dma_handle);
+	return vaddr;
 }
 EXPORT_SYMBOL_GPL(dma_alloc_noncoherent);
 
 void dma_free_noncoherent(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_handle, enum dma_data_direction dir)
 {
-	dma_free_pages(dev, size, virt_to_page(vaddr), dma_handle, dir);
+	const struct dma_map_ops *ops = get_dma_ops(dev);
+
+	if (!ops || !ops->free_noncoherent) {
+		dma_free_pages(dev, size, virt_to_page(vaddr), dma_handle, dir);
+		return;
+	}
+
+	size = PAGE_ALIGN(size);
+	debug_dma_unmap_page(dev, dma_handle, size, dir);
+	ops->free_noncoherent(dev, size, vaddr, dma_handle, dir);
 }
 EXPORT_SYMBOL_GPL(dma_free_noncoherent);
 
-- 
2.28.0