Hi CK,

Thanks for the reviews.

[snip]

quoted

We'll use cmdq_sec_pkt_set_data() to bring the secure scenario,
secure
engine flags and some secure metadata to TEE world. Then will used
these information to make sure the pipeline is secure.

We don't have the secure output feature currently, such as WiFi
display, so we'll do it after we have to support the feature.

Also there are HDMITX_HDCP and DPTX_HDCP TA will check the HDCP
statue
in secure world and then CMDQ TA will get that status by calling
their
API in TEE.
If CMDQ TA get a HDCP checking failed sstatus, it will insert some
instructions in the secure cmd buffer to mute the DISP HW for each
frames.

You enable secure path by crtc pipeline. That means it may be primary
display is secure and secondary display is non-secure. In
drivers/soc/mediatek/mt8195-mmsys.h, the primary display input could
be
routed to secondary display output. Is mmsys protected when display
is
secure? The whole mmsys is protected or partial mmsys is protected? 

VDOSYS0 has 2 pipelines and considering the scenario of using VDOSYS0-0 
as secure and VDOSYS0-0 as normal, we can not protect mmsys path mux
register.

If
the whole mmsys is protected, the non-secure display pipeline would
be
malfunctioned because the control of non-secure display is in normal
world and it may access mmsys. Please describe how this work?

For this case, we'll use CMDQ PTA to block the invalid instructions and
re-configure current mmsys path mux registers in every vblank interval
by GCE.

But we still have some works to do.
The main idea would be moving mmsys configure operation to the ATF.
Then protected the whole mmsys registers by DAPC.
So normal world can't write mmsys registers without passing smc call
cmd to ATF. ATF would check mux configure cmd is valid to current
scenario, then configures the valid mmsys mux registers.

Regards,
Jason-JH.Lin

Regards,
CK

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