Hi Chun-Kuang,

On Fri, 2020-07-31 at 23:55 +0800, Chun-Kuang Hu wrote:

Hi, Neal:

Neal Liu [off-list ref] 於 2020年7月31日 週五 上午10:52寫道：

quoted

Hi Chun-Kuang,

On Fri, 2020-07-31 at 00:14 +0800, Chun-Kuang Hu wrote:

quoted

Hi, Neal:

Neal Liu [off-list ref] 於 2020年7月29日 週三 下午4:29寫道：

quoted

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 <redacted>
---

[snip]

quoted

+
+/*
+ * devapc_extract_vio_dbg - extract full violation information after doing
+ *                          shift mechanism.
+ */
+static void devapc_extract_vio_dbg(struct mtk_devapc_context *ctx)
+{
+       const struct mtk_devapc_vio_dbgs *vio_dbgs;
+       struct mtk_devapc_vio_info *vio_info;
+       void __iomem *vio_dbg0_reg;
+       void __iomem *vio_dbg1_reg;
+       u32 dbg0;
+
+       vio_dbg0_reg = ctx->devapc_pd_base + ctx->offset->vio_dbg0;
+       vio_dbg1_reg = ctx->devapc_pd_base + ctx->offset->vio_dbg1;
+
+       vio_dbgs = ctx->vio_dbgs;
+       vio_info = ctx->vio_info;
+
+       /* Starts to extract violation information */
+       dbg0 = readl(vio_dbg0_reg);
+       vio_info->vio_addr = readl(vio_dbg1_reg);
+
+       vio_info->master_id = (dbg0 & vio_dbgs->mstid.mask) >>
+                             vio_dbgs->mstid.start;
+       vio_info->domain_id = (dbg0 & vio_dbgs->dmnid.mask) >>
+                             vio_dbgs->dmnid.start;
+       vio_info->write = ((dbg0 & vio_dbgs->vio_w.mask) >>
+                           vio_dbgs->vio_w.start) == 1;
+       vio_info->read = ((dbg0 & vio_dbgs->vio_r.mask) >>
+                         vio_dbgs->vio_r.start) == 1;
+       vio_info->vio_addr_high = (dbg0 & vio_dbgs->addr_h.mask) >>
+                                 vio_dbgs->addr_h.start;

I would like to define the type of ctx->vio_info to be

struct mtk_devapc_vio_dbgs {
    u32 mstid:16;
    u32 dmnid:6;
    u32 vio_w:1;
    u32 vio_r:1;
    u32 addr_h:4;
    u32 resv:4;
};

so the code would like the simple way

ctx->vio_info = (struct mtk_devapc_vio_dbgs)readl(vio_dbg1_reg);

This idea looks great! Is there any possible to pass the bit layout by
DT data, and still make this operation simple?
Why am I asking this question is because this bit layout is platform
dependent.

I doubt these info would be in a single 32-bits register for all
future SoC. If they are not in single 32-bits register, you may create
a vio_dbgs_type in DT data, and the code may be

if (ctx->vio_dbgs_type == VIO_DBGS_TYPE_MTxxxx) {
    ctx->vio_info = (struct mtk_devapc_vio_dbgs)readl(vio_dbg1_reg);
} else if (ctx->vio_dbgs_type == VIO_DBGS_TYPE_MTyyyy) {
    ctx->vio_info->mstid = readl(vio_mstid_reg);
    ctx->vio_info->dmnid = readl(vio_dmnid_reg);
    ctx->vio_info->vio_w = readl(vio_vio_w_reg);
    ctx->vio_info->vio_r = readl(vio_vio_r_reg);
}

I think we need not to consider how the future would be. Once the
second SoC driver is upstreaming, we could find out the best solution
for it.

Okay, I'll apply this on next patch.
Thanks !

Regards,
Chun-Kuang.

quoted

quoted

Regards,
Chun-Kuang.

quoted

+
+       devapc_vio_info_print(ctx);
+}
+

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