From: Chun-Kuang Hu <chunkuang.hu@kernel.org>
To: Neal Liu <neal.liu@mediatek.com>
Cc: Chun-Kuang Hu <chunkuang.hu@kernel.org>,
wsd_upstream <wsd_upstream@mediatek.com>,
devicetree@vger.kernel.org, lkml <linux-kernel@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 2/2] soc: mediatek: add mtk-devapc driver
Date: Tue, 4 Aug 2020 23:55:57 +0800 [thread overview]
Message-ID: <CAAOTY_-ndxjR1UQ4NQvxN3tVgT8t-cZb27j0U9Y7Q9CufUDc8Q@mail.gmail.com> (raw)
In-Reply-To: <1596506892.17917.2.camel@mtkswgap22>
Neal Liu <neal.liu@mediatek.com> 於 2020年8月4日 週二 上午10:08寫道:
>
> On Tue, 2020-08-04 at 00:04 +0800, Chun-Kuang Hu wrote:
> > Hi, Neal:
> >
> > Neal Liu <neal.liu@mediatek.com> 於 2020年8月3日 週一 下午12:01寫道:
> > >
> > > Hi Chun-Kuang,
> > >
> > > On Sat, 2020-08-01 at 08:12 +0800, Chun-Kuang Hu wrote:
> > > > Hi, Neal:
> > > >
> > > > This patch is for "mediatek,mt6779-devapc", so I think commit title
> > > > should show the SoC ID.
> > >
> > > Okay, I'll change title to 'soc:mediatek: add mt6779 devapc driver'.
> > >
> > > >
> > > > Neal Liu <neal.liu@mediatek.com> 於 2020年7月29日 週三 下午4:29寫道:
> > > > >
> > > > > MediaTek bus fabric provides TrustZone security support and data
> > > > > protection to prevent slaves from being accessed by unexpected
> > > > > masters.
> > > > > The security violation is logged and sent to the processor for
> > > > > further analysis or countermeasures.
> > > > >
> > > > > Any occurrence of security violation would raise an interrupt, and
> > > > > it will be handled by mtk-devapc driver. The violation
> > > > > information is printed in order to find the murderer.
> > > > >
> > > > > Signed-off-by: Neal Liu <neal.liu@mediatek.com>
> > > > > ---
> > > >
> > > > [snip]
> > > >
> > > > > +
> > > > > +struct mtk_devapc_context {
> > > > > + struct device *dev;
> > > > > + u32 vio_idx_num;
> > > > > + void __iomem *devapc_pd_base;
> > > > > + struct mtk_devapc_vio_info *vio_info;
> > > > > + const struct mtk_devapc_pd_offset *offset;
> > > > > + const struct mtk_devapc_vio_dbgs *vio_dbgs;
> > > > > +};
> > > >
> > > > I think this structure should separate the constant part. The constant part is:
> > > >
> > > > struct mtk_devapc_data {
> > > > const u32 vio_idx_num;
> > > > const struct mtk_devapc_pd_offset *offset; /* I would like to
> > > > remove struct mtk_devapc_pd_offset and directly put its member into
> > > > this structure */
> > > > const struct mtk_devapc_vio_dbgs *vio_dbgs; /* This may disappear */
> > > > };
> > > >
> > > > And the context is:
> > > >
> > > > struct mtk_devapc_context {
> > > > struct device *dev;
> > > > void __iomem *devapc_pd_base;
> > > > const struct mtk_devapc_data *data;
> > > > };
> > > >
> > > > So when you define this, you would not waste memory to store non-constant data.
> > > >
> > > > static const struct mtk_devapc_data devapc_mt6779 = {
> > > > .vio_idx_num = 510,
> > > > .offset = &mt6779_pd_offset,
> > > > .vio_dbgs = &mt6779_vio_dbgs,
> > > > };
> > > >
> > >
> > > Sorry, I still don't understand why this refactoring will not waste
> > > memory to store non-constant data. Could you explain more details?
> > > To my understanding, we still also have to allocate memory to store dev
> > > & devapc_pd_base.
> >
> > In some situation, it is. You make the non-constant data a global
> > variable. I think the context data should be dynamic allocated. If
> > this driver is not probed, the non-constant data occupy the memory.
> >
>
> I got your point! In this case, we can save these 2 data structure
> space, right?
>
> struct device *dev;
> void __iomem *devapc_pd_base;
Right.
>
> I'll refactoring this data structures on next patch. Thanks !
>
> > Regards,
> > Chun-Kuang.
> >
> > >
> > > > Regards,
> > > > Chun-Kuang.
> > > >
> > > > > +
> > > > > +#endif /* __MTK_DEVAPC_H__ */
> > > > > --
> > > > > 1.7.9.5
> > > > > _______________________________________________
> > > > > Linux-mediatek mailing list
> > > > > Linux-mediatek@lists.infradead.org
> > > > > http://lists.infradead.org/mailman/listinfo/linux-mediatek
> > >
>
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next prev parent reply other threads:[~2020-08-04 15:57 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 8:18 [PATCH v4] Add MediaTek MT6779 devapc driver Neal Liu
2020-07-29 8:18 ` [PATCH v4 1/2] dt-bindings: devapc: add bindings for mtk-devapc Neal Liu
2020-07-29 8:18 ` [PATCH v4 2/2] soc: mediatek: add mtk-devapc driver Neal Liu
2020-07-29 16:38 ` Chun-Kuang Hu
2020-07-31 2:44 ` Neal Liu
2020-07-31 15:03 ` Chun-Kuang Hu
2020-08-03 3:32 ` Neal Liu
2020-08-03 16:13 ` Chun-Kuang Hu
2020-08-04 2:18 ` Neal Liu
2020-08-04 15:27 ` Chun-Kuang Hu
2020-07-29 22:47 ` Chun-Kuang Hu
2020-07-31 2:47 ` Neal Liu
2020-07-30 16:14 ` Chun-Kuang Hu
2020-07-31 2:52 ` Neal Liu
2020-07-31 15:55 ` Chun-Kuang Hu
2020-08-03 3:41 ` Neal Liu
2020-08-01 0:12 ` Chun-Kuang Hu
2020-08-03 4:01 ` Neal Liu
2020-08-03 16:04 ` Chun-Kuang Hu
2020-08-04 2:08 ` Neal Liu
2020-08-04 15:55 ` Chun-Kuang Hu [this message]
2020-08-01 23:50 ` Chun-Kuang Hu
2020-08-03 4:05 ` Neal Liu
2020-08-03 15:38 ` Chun-Kuang Hu
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