3 files changed, 39 insertions, 0 deletions

diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index db5db02e885f..3fbedc75e7c5 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -218,6 +218,24 @@ void dmam_release_declared_memory(struct device *dev)
 }
 EXPORT_SYMBOL(dmam_release_declared_memory);
 
+/*
+ * Create scatter-list for the already allocated DMA buffer.
+ */
+int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
+                 void *cpu_addr, dma_addr_t handle, size_t size)
+{
+        struct page *page = virt_to_page(cpu_addr);
+        int ret;
+
+        ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+        if (unlikely(ret))
+                return ret;
+
+        sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+        return 0;
+}
+EXPORT_SYMBOL(dma_common_get_sgtable);
+
 #endif
 
 /*
diff --git a/include/asm-generic/dma-mapping-common.h b/include/asm-generic/dma-mapping-common.h
index 9073aeb3bb1a..de8bf89940f8 100644
--- a/include/asm-generic/dma-mapping-common.h
+++ b/include/asm-generic/dma-mapping-common.h
@@ -213,4 +213,22 @@ static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struc
         return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
 }
 
+int
+dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
+                       void *cpu_addr, dma_addr_t dma_addr, size_t size);
+
+static inline int
+dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
+                      dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs)
+{
+        struct dma_map_ops *ops = get_dma_ops(dev);
+        BUG_ON(!ops);
+        if (ops->get_sgtable)
+                return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size,
+                                        attrs);
+        return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size);
+}
+
+#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, NULL)
+
 #endif
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index dfc099e56a66..94af41858513 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -18,6 +18,9 @@ struct dma_map_ops {
         int (*mmap)(struct device *, struct vm_area_struct *,
                           void *, dma_addr_t, size_t, struct dma_attrs *attrs);
 
+        int (*get_sgtable)(struct device *dev, struct sg_table *sgt, void *,
+                           dma_addr_t, size_t, struct dma_attrs *attrs);
+
         dma_addr_t (*map_page)(struct device *dev, struct page *page,
                                unsigned long offset, size_t size,
                                enum dma_data_direction dir,