On 20/05/2021 13:05, dillon.minfei@xxxxxxxxx wrote: > From: Dillon Min <dillon.minfei@xxxxxxxxx> > > 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 I'm getting checkpatch.pl --strict warnings: CHECK: Alignment should match open parenthesis #31: FILE: drivers/media/v4l2-core/v4l2-mem2mem.c:971: +unsigned long v4l2_m2m_get_unmapped_area(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, unsigned long flags) CHECK: Alignment should match open parenthesis #62: FILE: include/media/v4l2-mem2mem.h:500: +unsigned long v4l2_m2m_get_unmapped_area(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, unsigned long flags); Regards, Hans > > Signed-off-by: Dillon Min <dillon.minfei@xxxxxxxxx> > --- > drivers/media/v4l2-core/v4l2-mem2mem.c | 20 ++++++++++++++++++++ > include/media/v4l2-mem2mem.h | 4 ++++ > 2 files changed, 24 insertions(+) > > diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c > index e7f4bf5bc8dd..f82a18ecab2f 100644 > --- a/drivers/media/v4l2-core/v4l2-mem2mem.c > +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c > @@ -966,6 +966,26 @@ 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..91269227c265 100644 > --- a/include/media/v4l2-mem2mem.h > +++ b/include/media/v4l2-mem2mem.h > @@ -495,6 +495,10 @@ __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 > * >