From: Neal Liu <neal.liu@mediatek.com>
To: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Cc: Neal Liu <neal.liu@mediatek.com>,
Rob Herring <robh+dt@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
<devicetree@vger.kernel.org>,
wsd_upstream <wsd_upstream@mediatek.com>,
lkml <linux-kernel@vger.kernel.org>,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 2/2] soc: mediatek: add mtk-devapc driver
Date: Fri, 10 Jul 2020 11:23:43 +0800 [thread overview]
Message-ID: <1594351423.4670.18.camel@mtkswgap22> (raw)
In-Reply-To: <CAAOTY_-7PwoPG_0ce2p4BCNQ3rundg40Bsni14XSmVETExkKkw@mail.gmail.com>
Hi Chun-Kuang,
Thanks for your review.
On Thu, 2020-07-09 at 21:01 +0800, Chun-Kuang Hu wrote:
> Hi, Neal:
>
> Neal Liu <neal.liu@mediatek.com> 於 2020年7月9日 週四 下午5:13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]
>
> > +
> > +static u32 get_shift_group(struct mtk_devapc_context *devapc_ctx,
> > + int slave_type, int vio_idx)
>
> vio_idx is useless, so remove it.
>
yes, my mistake. I'll remove it on next patch.
> > +{
> > + u32 vio_shift_sta;
> > + void __iomem *reg;
> > + int bit;
> > +
> > + reg = mtk_devapc_pd_get(devapc_ctx, slave_type, VIO_SHIFT_STA, 0);
> > + vio_shift_sta = readl(reg);
> > +
> > + for (bit = 0; bit < 32; bit++) {
> > + if ((vio_shift_sta >> bit) & 0x1)
> > + break;
> > + }
> > +
> > + return bit;
> > +}
> > +
>
> [snip]
>
> > +
> > +/*
> > + * devapc_violation_irq - the devapc Interrupt Service Routine (ISR) will dump
> > + * violation information including which master violates
> > + * access slave.
> > + */
> > +static irqreturn_t devapc_violation_irq(int irq_number,
> > + struct mtk_devapc_context *devapc_ctx)
> > +{
> > + const struct mtk_device_info **device_info;
> > + int slave_type_num;
> > + int vio_idx = -1;
> > + int slave_type;
> > +
> > + slave_type_num = devapc_ctx->slave_type_num;
> > + device_info = devapc_ctx->device_info;
> > +
> > + for (slave_type = 0; slave_type < slave_type_num; slave_type++) {
>
> If slave_type_num is 1, I think the code should be simpler.
slave_type_num is depends on DT data, it's not always 1.
>
> > + if (!mtk_devapc_dump_vio_dbg(devapc_ctx, slave_type, &vio_idx))
> > + continue;
> > +
> > + /* Ensure that violation info are written before
> > + * further operations
> > + */
> > + smp_mb();
> > +
> > + mask_module_irq(devapc_ctx, slave_type, vio_idx, true);
>
> Why do you mask irq?
It has to mask slave's irq before clear violation status.
It's one of hardware design.
>
> > +
> > + clear_vio_status(devapc_ctx, slave_type, vio_idx);
> > +
> > + mask_module_irq(devapc_ctx, slave_type, vio_idx, false);
> > + }
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +/*
> > + * start_devapc - initialize devapc status and start receiving interrupt
> > + * while devapc violation is triggered.
> > + */
>
> [snip]
>
> > +
> > +struct mtk_device_info {
> > + int sys_index;
>
> Useless, so remove it.
We need to print it as our debug information.
But I did not apply it on this patch, I'll add it on next patch.
>
> > + int ctrl_index;
>
> Ditto.
>
> Regards,
> Chun-Kuang.
>
> > + int vio_index;
> > +};
> > +
next prev parent reply other threads:[~2020-07-10 3:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 9:12 [PATCH v2] Add MediaTek MT6779 devapc driver Neal Liu
2020-07-09 9:12 ` [PATCH v2 1/2] dt-bindings: devapc: add bindings for mtk-devapc Neal Liu
2020-07-10 10:41 ` Matthias Brugger
2020-07-14 3:17 ` Neal Liu
2020-07-09 9:12 ` [PATCH v2 2/2] soc: mediatek: add mtk-devapc driver Neal Liu
2020-07-09 13:01 ` Chun-Kuang Hu
2020-07-10 3:23 ` Neal Liu [this message]
2020-07-10 14:21 ` Chun-Kuang Hu
2020-07-13 8:27 ` Neal Liu
2020-07-13 14:20 ` Chun-Kuang Hu
2020-07-14 3:06 ` Neal Liu
2020-07-10 12:14 ` Matthias Brugger
2020-07-13 7:45 ` Neal Liu
2020-07-13 11:16 ` Matthias Brugger
2020-07-14 2:45 ` Neal Liu
2020-07-15 23:46 ` Chun-Kuang Hu
2020-07-16 3:42 ` Neal Liu
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