[media] vb2: add vb2_get_unmapped_area in vb2 core

no mmu system needs get_unmapped_area file operations to do mmap
Signed-off-by: NScott Jiang <scott.jiang.linux@gmail.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/videobuf2-core.c

@@ -1567,6 +1567,37 @@ int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma)
 }
 EXPORT_SYMBOL_GPL(vb2_mmap);
 
+#ifndef CONFIG_MMU
+unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
+				    unsigned long addr,
+				    unsigned long len,
+				    unsigned long pgoff,
+				    unsigned long flags)
+{
+	unsigned long off = pgoff << PAGE_SHIFT;
+	struct vb2_buffer *vb;
+	unsigned int buffer, plane;
+	int ret;
+
+	if (q->memory != V4L2_MEMORY_MMAP) {
+		dprintk(1, "Queue is not currently set up for mmap\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Find the plane corresponding to the offset passed by userspace.
+	 */
+	ret = __find_plane_by_offset(q, off, &buffer, &plane);
+	if (ret)
+		return ret;
+
+	vb = q->bufs[buffer];
+
+	return (unsigned long)vb2_plane_vaddr(vb, plane);
+}
+EXPORT_SYMBOL_GPL(vb2_get_unmapped_area);
+#endif
+
 static int __vb2_init_fileio(struct vb2_queue *q, int read);
 static int __vb2_cleanup_fileio(struct vb2_queue *q);
 

include/media/videobuf2-core.h

@@ -322,6 +322,13 @@ int vb2_streamon(struct vb2_queue *q, enum v4l2_buf_type type);
 int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type);
 
 int vb2_mmap(struct vb2_queue *q, struct vm_area_struct *vma);
+#ifndef CONFIG_MMU
+unsigned long vb2_get_unmapped_area(struct vb2_queue *q,
+				    unsigned long addr,
+				    unsigned long len,
+				    unsigned long pgoff,
+				    unsigned long flags);
+#endif
 unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait);
 size_t vb2_read(struct vb2_queue *q, char __user *data, size_t count,
 		loff_t *ppos, int nonblock);