Hi Hans,

On Thu, Jun 17, 2021 at 5:58 PM Hans Verkuil [off-list ref] wrote:

On 20/05/2021 13:05, dillon.minfei@gmail.com wrote:

quoted

From: Dillon Min <redacted>

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);

Okay, I will add the "--strict" check to my regular patch submission.
Thanks for the reminder.

Best Regards
Dillon

Regards,

        Hans

quoted

Signed-off-by: Dillon Min <redacted>
---
 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
  *

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