linux-kernel - Re: [PATCH v4 6/8] soc: mediatek: Add programming flow for unsupported subsys ID hardware

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Message-ID: <ddcf01c82f92ee461875e1122b009b7fca691127.camel@mediatek.com>
Date: Wed, 5 Mar 2025 16:12:39 +0000
From: Jason-JH Lin (林睿祥) <Jason-JH.Lin@...iatek.com>
To: "robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
	<krzk+dt@...nel.org>, AngeloGioacchino Del Regno
	<angelogioacchino.delregno@...labora.com>, "conor+dt@...nel.org"
	<conor+dt@...nel.org>, "mchehab@...nel.org" <mchehab@...nel.org>,
	"chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>,
	"jassisinghbrar@...il.com" <jassisinghbrar@...il.com>
CC: "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
	Sirius Wang (王皓昱) <Sirius.Wang@...iatek.com>,
	Moudy Ho (何宗原) <Moudy.Ho@...iatek.com>,
	Nancy Lin (林欣螢) <Nancy.Lin@...iatek.com>,
	Xiandong Wang (王先冬)
	<Xiandong.Wang@...iatek.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, Project_Global_Chrome_Upstream_Group
	<Project_Global_Chrome_Upstream_Group@...iatek.com>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
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	Singo Chang (張興國) <Singo.Chang@...iatek.com>,
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	Xavier Chang (張獻文) <Xavier.Chang@...iatek.com>,
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	<treapking@...omium.org>
Subject: Re: [PATCH v4 6/8] soc: mediatek: Add programming flow for
 unsupported subsys ID hardware

On Tue, 2025-03-04 at 10:41 +0100, AngeloGioacchino Del Regno wrote:
> 
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
> 
> 
> Il 18/02/25 06:41, Jason-JH Lin ha scritto:
> > To support hardware without subsys IDs on new SoCs, add a
> > programming
> > flow that checks whether the subsys ID is valid. If the subsys ID
> > is
> > invalid, the flow will call 2 alternative CMDQ APIs:
> > cmdq_pkt_assign() and cmdq_pkt_write_s_value() to achieve the same
> > functionality.
> > 
> > Signed-off-by: Jason-JH Lin <jason-jh.lin@...iatek.com>
> > ---
> >   drivers/soc/mediatek/mtk-mmsys.c | 14 +++++++++++---
> >   drivers/soc/mediatek/mtk-mutex.c | 11 +++++++++--
> >   2 files changed, 20 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/soc/mediatek/mtk-mmsys.c
> > b/drivers/soc/mediatek/mtk-mmsys.c
> > index bb4639ca0b8c..ce949b863b05 100644
> > --- a/drivers/soc/mediatek/mtk-mmsys.c
> > +++ b/drivers/soc/mediatek/mtk-mmsys.c
> > @@ -167,9 +167,17 @@ static void mtk_mmsys_update_bits(struct
> > mtk_mmsys *mmsys, u32 offset, u32 mask,
> >       u32 tmp;
> > 
> >       if (mmsys->cmdq_base.size && cmdq_pkt) {
> > -             ret = cmdq_pkt_write_mask(cmdq_pkt, mmsys-
> > >cmdq_base.subsys,
> > -                                       mmsys->cmdq_base.offset +
> > offset, val,
> > -                                       mask);
> > +             offset += mmsys->cmdq_base.offset;
> > +             if (mmsys->cmdq_base.subsys != CMDQ_SUBSYS_INVALID) {
> 
> You're still anyway passing the subsys to cmdq_pkt_write_mask(),
> right?!
> Why don't you just handle this in cmdq_pkt_write_mask() then? ;-)
> 
> I can see this pattern being repeated over and over in both
> drm/mediatek and MDP3
> drivers, and it's not necessary to duplicate this many times when you
> can write it
> just once.
> 
> Would've also been faster for you to implement... :-D
> 

I think did it in the series V1:
https://patchwork.kernel.org/project/linux-mediatek/patch/20241121042602.32730-5-jason-jh.lin@mediatek.com/

Because it'll need to passing the base_pa and that will need to change
the interface for original APIs.

And CK think that's not a necessary to change the APIs. It can be done
by cmdq_pkt_assign() + cmdq_pkt_write_s_mask_value() in the client
drivers. Then you can see this pattern in everywhere. :-)

Regards,
Jason-JH Lin

> Cheers,
> Angelo