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@xxxxxxxxx>
---
v6: no change.
drivers/media/v4l2-core/v4l2-mem2mem.c | 21 +++++++++++++++++++++
include/media/v4l2-mem2mem.h | 5 +++++
2 files changed, 26 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
index e7f4bf5bc8dd..e2654b422334 100644
--- 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 5a91b548ecc0..fdbd5257e020 100644
--- 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
*
--
2.7.4
