media: v4l2-mem2mem: add v4l2_m2m_get_unmapped_area for no-mmu platform

For platforms without MMU the m2m provides a helper method
v4l2_m2m_get_unmapped_area(), The mmap() routines will call
this to get a proposed address for the mapping.

More detailed information about get_unmapped_area can be found in
Documentation/nommu-mmap.txt

Signed-off-by: Dillon Min <dillon.minfei@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
index e7f4bf5..e2654b4 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-mem2mem.c
+++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
@@ -966,6 +966,27 @@ int v4l2_m2m_mmap(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 }
 EXPORT_SYMBOL(v4l2_m2m_mmap);
 
+#ifndef CONFIG_MMU
+unsigned long v4l2_m2m_get_unmapped_area(struct file *file, unsigned long addr,
+                                        unsigned long len, unsigned long pgoff,
+                                        unsigned long flags)
+{
+       struct v4l2_fh *fh = file->private_data;
+       unsigned long offset = pgoff << PAGE_SHIFT;
+       struct vb2_queue *vq;
+
+       if (offset < DST_QUEUE_OFF_BASE) {
+               vq = v4l2_m2m_get_src_vq(fh->m2m_ctx);
+       } else {
+               vq = v4l2_m2m_get_dst_vq(fh->m2m_ctx);
+               pgoff -= (DST_QUEUE_OFF_BASE >> PAGE_SHIFT);
+       }
+
+       return vb2_get_unmapped_area(vq, addr, len, pgoff, flags);
+}
+EXPORT_SYMBOL_GPL(v4l2_m2m_get_unmapped_area);
+#endif
+
 #if defined(CONFIG_MEDIA_CONTROLLER)
 void v4l2_m2m_unregister_media_controller(struct v4l2_m2m_dev *m2m_dev)
 {

diff --git a/include/media/v4l2-mem2mem.h b/include/media/v4l2-mem2mem.h
index 5a91b54..fdbd525 100644 (file)
--- a/include/media/v4l2-mem2mem.h
+++ b/include/media/v4l2-mem2mem.h
@@ -495,6 +495,11 @@ __poll_t v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
 int v4l2_m2m_mmap(struct file *file, struct v4l2_m2m_ctx *m2m_ctx,
                  struct vm_area_struct *vma);
 
+#ifndef CONFIG_MMU
+unsigned long v4l2_m2m_get_unmapped_area(struct file *file, unsigned long addr,
+                                        unsigned long len, unsigned long pgoff,
+                                        unsigned long flags);
+#endif
 /**
  * v4l2_m2m_init() - initialize per-driver m2m data
  *