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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Date: Tue, 16 Apr 2024 15:32:02 +0300
Message-ID: <CAA8EJpqHOWCLg65TSrpy6eh2kFL2=5uu8Kp+WKqu8dLZdowfZA@mail.gmail.com>
Subject: Re: [PATCH v2 2/4] dt-bindings: arm: Document reboot mode magic
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: Elliot Berman <quic_eberman@quicinc.com>, Bjorn Andersson <andersson@kernel.org>, 
	Konrad Dybcio <konrad.dybcio@linaro.org>, Sebastian Reichel <sre@kernel.org>, Rob Herring <robh@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Vinod Koul <vkoul@kernel.org>, Andy Yan <andy.yan@rock-chips.com>, 
	Lorenzo Pieralisi <lpieralisi@kernel.org>, Mark Rutland <mark.rutland@arm.com>, 
	Bartosz Golaszewski <bartosz.golaszewski@linaro.org>, 
	Satya Durga Srinivasu Prabhala <quic_satyap@quicinc.com>, Melody Olvera <quic_molvera@quicinc.com>, 
	Shivendra Pratap <quic_spratap@quicinc.com>, devicetree@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, 
	Florian Fainelli <florian.fainelli@broadcom.com>, linux-pm@vger.kernel.org, 
	linux-arm-msm@vger.kernel.org
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On Tue, 16 Apr 2024 at 12:30, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
> On Sun, Apr 14, 2024 at 12:30:25PM -0700, Elliot Berman wrote:
> > Add bindings to describe vendor-specific reboot modes. Values here
> > correspond to valid parameters to vendor-specific reset types in PSCI
> > SYSTEM_RESET2 call.
> >
>
> IIUC, PSCI SYSTEM_RESET will be always supported, so the choice of using
> SYSTEM_RESET2 sounds like a system policy and must not have any information
> in the device tree. All required support from PSCI is discoverable and
> the policy choice must be userspace driven. That's my opinion.

Well, we are talking about the vendor-specific resets, which are not
discoverable. The spec defines them as "implementation defined".
For example, PCSI spec doesn't define a way to add "reset to
bootloader" or "reset to recovery" kinds of resets.

I think the bindings at least should make it clear that the vendor bit
it being set automatically. I won't comment whether this is a good
decision or not.

-- 
With best wishes
Dmitry