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From:   "Aakarsh Jain" <aakarsh.jain@samsung.com>
To:     "'Hans Verkuil'" <hverkuil-cisco@xs4all.nl>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-media@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
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        <mchehab@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <robh+dt@kernel.org>, <conor+dt@kernel.org>,
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        <gost.dev@samsung.com>, <alim.akhtar@samsung.com>,
        <aswani.reddy@samsung.com>, <pankaj.dubey@samsung.com>,
        <ajaykumar.rs@samsung.com>, <linux-fsd@tesla.com>,
        "'Smitha T Murthy'" <smithatmurthy@gmail.com>
In-Reply-To: <2c9b85dc-ebd7-43a7-bb66-d96ba9a28082@xs4all.nl>
Subject: RE: [Patch v5 09/11] media: s5p-mfc: Load firmware for each run in
 MFCv12.
Date:   Wed, 13 Dec 2023 13:29:49 +0530
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> -----Original Message-----
> From: Hans Verkuil <hverkuil-cisco=40xs4all.nl>
> Sent: 06 December 2023 18:28
> To: Aakarsh Jain <aakarsh.jain=40samsung.com>; linux-arm-
> kernel=40lists.infradead.org; linux-media=40vger.kernel.org; linux-
> kernel=40vger.kernel.org; devicetree=40vger.kernel.org
> Cc: m.szyprowski=40samsung.com; andrzej.hajda=40intel.com;
> mchehab=40kernel.org; krzysztof.kozlowski+dt=40linaro.org;
> robh+dt=40kernel.org; conor+dt=40kernel.org; linux-samsung-
> soc=40vger.kernel.org; andi=40etezian.org; gost.dev=40samsung.com;
> alim.akhtar=40samsung.com; aswani.reddy=40samsung.com;
> pankaj.dubey=40samsung.com; ajaykumar.rs=40samsung.com; linux-
> fsd=40tesla.com; Smitha T Murthy <smithatmurthy=40gmail.com>
> Subject: Re: =5BPatch v5 09/11=5D media: s5p-mfc: Load firmware for each =
run in
> MFCv12.
>=20
> On 06/12/2023 07:30, Aakarsh Jain wrote:
> > In MFCv12, some section of firmware gets updated at each MFC run.
> > Hence we need to reload original firmware for each run at the start.
> >
> > Cc: linux-fsd=40tesla.com
> > Signed-off-by: Smitha T Murthy <smithatmurthy=40gmail.com>
> > Signed-off-by: Aakarsh Jain <aakarsh.jain=40samsung.com>
> > ---
> >  drivers/media/platform/samsung/s5p-mfc/s5p_mfc_ctrl.c =7C 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_ctrl.c
> > b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_ctrl.c
> > index b49159142c53..24dd40ae71ec 100644
> > --- a/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_ctrl.c
> > +++ b/drivers/media/platform/samsung/s5p-mfc/s5p_mfc_ctrl.c
> > =40=40 -51,8 +51,10 =40=40 int s5p_mfc_load_firmware(struct s5p_mfc_dev
> *dev)
> >  	 * into kernel. */
> >  	mfc_debug_enter();
> >
> > -	if (dev->fw_get_done)
> > -		return 0;
> > +	/* Load MFC v12 firmware for each run when MFC runs sequentially
> */
>=20
> You had a much longer explanation in your reply to my original question.
>=20
> I think it is better if that longer explanation is added here.
>=20
okay sure. Will add that explanation here.

> Things that are weird and unexpected need good comments, explaining why
> it is done, and also what you know and do not know about this.
>=20
> E.g. you know through trial and error that it is needed (or perhaps you g=
ot
> information on this some the fw team), but there might be open questions
> that are not yet answered.
>=20
> This is all information that you can't get from the source code since it =
has to
> do with the black box firmware. So putting all you know in a comment is t=
he
> best way of communicating this to future readers of the source code.
>=20

Thanks for the review=21

> Regards,
>=20
> 	Hans
>=20
> > +	if (=21IS_MFCV12(dev))
> > +		if (dev->fw_get_done)
> > +			return 0;
> >
> >  	for (i =3D MFC_FW_MAX_VERSIONS - 1; i >=3D 0; i--) =7B
> >  		if (=21dev->variant->fw_name=5Bi=5D)