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 <20231206081538.17056-5-yunfei.dong@mediatek.com> <ce2110bf-a16a-45ae-979b-7e41be2896cd@xs4all.nl>
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From: Jeffrey Kardatzke <jkardatzke@google.com>
Date: Thu, 4 Jan 2024 12:05:39 -0800
Message-ID: <CA+ddPcM6nz0ufF5NXUq7E_vF6HnFKrEEag5iUDAknT6=hWTCNQ@mail.gmail.com>
Subject: Re: [PATCH v3,04/21] v4l: add documentation for secure memory flag
To: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Yunfei Dong <yunfei.dong@mediatek.com>, 
	=?UTF-8?B?TsOtY29sYXMgRiAuIFIgLiBBIC4gUHJhZG8=?= <nfraprado@collabora.com>, 
	Nicolas Dufresne <nicolas.dufresne@collabora.com>, 
	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>, 
	Benjamin Gaignard <benjamin.gaignard@collabora.com>, Nathan Hebert <nhebert@chromium.org>, 
	Chen-Yu Tsai <wenst@chromium.org>, Yong Wu <yong.wu@mediatek.com>, 
	Hsin-Yi Wang <hsinyi@chromium.org>, Fritz Koenig <frkoenig@chromium.org>, 
	Daniel Vetter <daniel@ffwll.ch>, Steve Cho <stevecho@chromium.org>, 
	Sumit Semwal <sumit.semwal@linaro.org>, Brian Starkey <Brian.Starkey@arm.com>, 
	John Stultz <jstultz@google.com>, "T . J . Mercier" <tjmercier@google.com>, 
	=?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>, 
	Matthias Brugger <matthias.bgg@gmail.com>, dri-devel@lists.freedesktop.org, 
	linaro-mm-sig@lists.linaro.org, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 
	linux-mediatek@lists.infradead.org, 
	Project_Global_Chrome_Upstream_Group@mediatek.com
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On Mon, Dec 11, 2023 at 3:05=E2=80=AFAM Hans Verkuil <hverkuil-cisco@xs4all=
.nl> wrote:
>
> On 06/12/2023 09:15, Yunfei Dong wrote:
> > From: Jeffrey Kardatzke <jkardatzke@google.com>
> >
> > Adds documentation for V4L2_MEMORY_FLAG_SECURE.
> >
> > Signed-off-by: Jeffrey Kardatzke <jkardatzke@google.com>
> > Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
> > ---
> >  Documentation/userspace-api/media/v4l/buffer.rst | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documen=
tation/userspace-api/media/v4l/buffer.rst
> > index 52bbee81c080..a5a7d1c72d53 100644
> > --- a/Documentation/userspace-api/media/v4l/buffer.rst
> > +++ b/Documentation/userspace-api/media/v4l/buffer.rst
> > @@ -696,7 +696,7 @@ enum v4l2_memory
> >
> >  .. _memory-flags:
> >
> > -Memory Consistency Flags
> > +Memory Flags
> >  ------------------------
> >
> >  .. raw:: latex
> > @@ -728,6 +728,12 @@ Memory Consistency Flags
> >       only if the buffer is used for :ref:`memory mapping <mmap>` I/O a=
nd the
> >       queue reports the :ref:`V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS
> >       <V4L2-BUF-CAP-SUPPORTS-MMAP-CACHE-HINTS>` capability.
> > +    * .. _`V4L2-MEMORY-FLAG-SECURE`:
> > +
> > +      - ``V4L2_MEMORY_FLAG_SECURE``
> > +      - 0x00000002
> > +      - DMA bufs passed into the queue will be validated to ensure the=
y were
> > +     allocated from a secure dma-heap.
>
> Hmm, that needs a bit more work. How about:
>
> - The queued buffers are expected to be in secure memory. If not, an erro=
r will be
>   returned. This flag can only be used with ``V4L2_MEMORY_DMABUF``. Typic=
ally
>   secure buffers are allocated using a secure dma-heap. This flag can onl=
y be
>   specified if the ``V4L2_BUF_CAP_SUPPORTS_SECURE_MEM`` is set.
>

Thanks Hans. Yunfei, can you integrate this change into the patch please?

> In addition, the title of this table is currently "Memory Consistency Fla=
gs": that
> should be renamed to "Memory Flags".

Hans, the patch is already renaming the table as you suggested. :)
(unless there's some other spot I'm missing)
>
> Regards,
>
>         Hans
>
> >
> >  .. raw:: latex
> >
>