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From: Brian Norris <computersforpeace@gmail.com>
To: Robert Marko <robimarko@gmail.com>
Cc: Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	agross@kernel.org, andersson@kernel.org,
	konrad.dybcio@linaro.org, krzysztof.kozlowski+dt@linaro.org,
	conor+dt@kernel.org, quic_gurus@quicinc.com,
	linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/5] dt-bindings: firmware: qcom,scm: Document SDI disable
Date: Mon, 21 Aug 2023 12:44:41 -0700	[thread overview]
Message-ID: <CAN8TOE96PjH67+vmi7mksSvqeMdLNBd8MH3m=1Ft_h+TXbk4BA@mail.gmail.com> (raw)
In-Reply-To: <CAOX2RU6be+eeTPT7HbC8_-C7d7oVhspsXWOmwtgg6s=QMe6QEg@mail.gmail.com>

On Mon, Aug 21, 2023 at 12:35 PM Robert Marko <robimarko@gmail.com> wrote:
> On Mon, 21 Aug 2023 at 21:31, Rob Herring <robh@kernel.org> wrote:
> > Why can't you just disable SDI unconditionally when going into debug
> > mode? Is doing that when not enabled going to crash the system or
> > something?

I asked the same, to resounding silence:

https://lore.kernel.org/all/20200721080054.2803881-1-computersforpeace@gmail.com/
https://lore.kernel.org/all/ZNlhSdh0qDMieTAS@localhost/

> Because if not disabled you will enter the Secure Debug mode even on a
> regular reboot and then you have to pull the power in order to boot again.
> Even according to QCA docs they intended for the Linux to disable SDI as
> TZ/QSEE will always enable it as part of booting.

NB: I've never read such docs. Presumably they're internal/private to
Qualcomm and/or its direct partners? I'd love to see them.

But, I think you (robinmarko) are not really answering the same
question that Rob (robh) is asking. Rob is asking why you ever *don't*
want to disable SDI. You're answering why we ever need to disable it
at all. I don't think the latter question is controversial.

FWIW, your description of those docs sounds like we should
unconditionally *disable* SDI (like my first RFC above), which would
answer Rob's question, and would agree with my RFC above :) And as a
bonus, no Device Tree change would be required.

Brian

  reply	other threads:[~2023-08-21 19:45 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-15 13:59 [PATCH v2 1/5] dt-bindings: firmware: qcom,scm: Document SDI disable Robert Marko
2023-08-15 13:59 ` [PATCH v2 2/5] firmware: qcom: scm: Add SDI disable support Robert Marko
2023-08-16  6:15   ` Krzysztof Kozlowski
2023-08-15 13:59 ` [PATCH v2 3/5] firmware: qcom_scm: disable SDI if required Robert Marko
2023-08-15 13:59 ` [PATCH v2 4/5] dt-bindings: firmware: qcom,scm: document IPQ5018 compatible Robert Marko
2023-08-16  6:10   ` Krzysztof Kozlowski
2023-09-15 12:23     ` Sricharan Ramabadhran
2023-09-15 12:31       ` Krzysztof Kozlowski
2023-08-15 13:59 ` [PATCH v2 5/5] arm64: dts: qcom: ipq5018: indicate that SDI should be disabled Robert Marko
2023-08-16  6:15 ` [PATCH v2 1/5] dt-bindings: firmware: qcom,scm: Document SDI disable Krzysztof Kozlowski
2023-08-21 19:31   ` Rob Herring
2023-08-21 19:35     ` Robert Marko
2023-08-21 19:44       ` Brian Norris [this message]
2023-08-21 20:39         ` Robert Marko

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