Implement support for allocating a non-contiguous DMA region.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/iommu/dma-iommu.c | 47 +++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 65af875ba8495c..938a2856b4a455 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -756,6 +756,49 @@ static void *iommu_dma_alloc_remap(struct device *dev, size_t size,
return NULL;
}
+#ifdef CONFIG_DMA_REMAP
+static struct sg_table *iommu_dma_alloc_noncontiguous(struct device *dev,
+ size_t size, dma_addr_t *dma_handle,
+ enum dma_data_direction dir, gfp_t gfp)
+{
+ unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+ struct dma_sgt_handle *sh;
+
+ sh = kmalloc(sizeof(*sh), gfp);
+ if (!sh)
+ return NULL;
+
+ sh->pages = __iommu_dma_alloc_noncontiguous(dev, size, &sh->sgt,
+ dma_handle, gfp,
+ PAGE_KERNEL, 0);
+ if (!sh->pages)
+ goto out_free_sh;
+
+ if (sg_alloc_table_from_pages(&sh->sgt, sh->pages, count, 0, size,
+ GFP_KERNEL))
+ goto out_free_pages;
+
+ return &sh->sgt;
+
+out_free_pages:
+ __iommu_dma_free_pages(sh->pages, count);
+out_free_sh:
+ kfree(sh);
+ return NULL;
+}
+
+static void iommu_dma_free_noncontiguous(struct device *dev, size_t size,
+ struct sg_table *sgt, dma_addr_t dma_handle,
+ enum dma_data_direction dir)
+{
+ struct dma_sgt_handle *sh = sgt_handle(sgt);
+
+ __iommu_dma_unmap(dev, dma_handle, size);
+ __iommu_dma_free_pages(sh->pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
+ sg_free_table(&sh->sgt);
+}
+#endif /* CONFIG_DMA_REMAP */
+
static void iommu_dma_sync_single_for_cpu(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{
@@ -1271,6 +1314,10 @@ static const struct dma_map_ops iommu_dma_ops = {
.free = iommu_dma_free,
.alloc_pages = dma_common_alloc_pages,
.free_pages = dma_common_free_pages,
+#ifdef CONFIG_DMA_REMAP
+ .alloc_noncontiguous = iommu_dma_alloc_noncontiguous,
+ .free_noncontiguous = iommu_dma_free_noncontiguous,
+#endif
.mmap = iommu_dma_mmap,
.get_sgtable = iommu_dma_get_sgtable,
.map_page = iommu_dma_map_page,
--
2.29.2
