[PATCH v2 3/4] media: videobuf2-dma-contig: use dma_mmap_coherent if available

[Hideki EIRAKU]

Previously the vb2_dma_contig_mmap() function was using a dma_addr_t as a
physical address.  The two addressses are not necessarily the same.
For example, when using the IOMMU funtion on certain platforms, dma_addr_t
addresses are not directly mappable physical address.
dma_mmap_coherent() maps the address correctly.
It is available on ARM platforms.

Signed-off-by: Hideki EIRAKU <hdk at igel.co.jp>
---
 drivers/media/video/videobuf2-dma-contig.c |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/videobuf2-dma-contig.c b/drivers/media/video/videobuf2-dma-contig.c
index 4b71326..4dc85ab 100644
--- a/drivers/media/video/videobuf2-dma-contig.c
+++ b/drivers/media/video/videobuf2-dma-contig.c
@@ -101,14 +101,32 @@ static unsigned int vb2_dma_contig_num_users(void *buf_priv)
 static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
 {
 	struct vb2_dc_buf *buf = buf_priv;
+#ifdef ARCH_HAS_DMA_MMAP_COHERENT
+	int ret;
+#endif
 
 	if (!buf) {
 		printk(KERN_ERR "No buffer to map\n");
 		return -EINVAL;
 	}
 
+#ifdef ARCH_HAS_DMA_MMAP_COHERENT
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	ret = dma_mmap_coherent(buf->conf->dev, vma, buf->vaddr, buf->dma_addr,
+				buf->size);
+	if (ret) {
+		pr_err("Remapping memory failed, error: %d\n", ret);
+		return ret;
+	}
+	vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
+	vma->vm_private_data = &buf->handler;
+	vma->vm_ops = &vb2_common_vm_ops;
+	vma->vm_ops->open(vma);
+	return 0;
+#else
 	return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
 				  &vb2_common_vm_ops, &buf->handler);
+#endif
 }
 
 static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
-- 
1.7.0.4