Re: [PATCH v4 7/7] arm64: dts: exynos: Add initial device tree support for Exynos7885 SoC

From: Marc Zyngier <maz@kernel.org>
To: David Virag <virag.david003@gmail.com>
Cc: Sam Protsenko <semen.protsenko@linaro.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	Rob Herring <robh+dt@kernel.org>,
	Sylwester Nawrocki <s.nawrocki@samsung.com>,
	Tomasz Figa <tomasz.figa@gmail.com>,
	Chanwoo Choi <cw00.choi@samsung.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org
Subject: Re: [PATCH v4 7/7] arm64: dts: exynos: Add initial device tree support for Exynos7885 SoC
Date: Mon, 20 Dec 2021 08:44:37 +0000	[thread overview]
Message-ID: <87o85bwtqi.wl-maz@kernel.org> (raw)
In-Reply-To: <cc27e22d9945b1ab5ccc7ef20eb36af63402ef54.camel@gmail.com>

On Sun, 19 Dec 2021 14:36:20 +0000,
David Virag <virag.david003@gmail.com> wrote:
> 
> On Tue, 2021-12-07 at 19:42 +0000, Marc Zyngier wrote:
> > On 2021-12-06 15:31, David Virag wrote:
> > > Add initial Exynos7885 device tree nodes with dts for the Samsung 
> > > Galaxy
> > > A8 (2018), a.k.a. "jackpotlte", with model number "SM-A530F".
> > > Currently this includes some clock support, UART support, and I2C 
> > > nodes.
> > > 
> > > Signed-off-by: David Virag <virag.david003@gmail.com>
> > 
> > [...]
> > 
> > > +       psci {
> > > +               compatible = "arm,psci";
> > > +               method = "smc";
> > > +               cpu_suspend = <0xc4000001>;
> > > +               cpu_off = <0x84000002>;
> > > +               cpu_on = <0xc4000003>;
> > 
> > Aren't these the standard PSCI 0.2 function numbers? Can't you
> > make the compatible "arm,psci-0.2" instead?
> 
> This is not a proper PSCI 0.2 implementation. For example 0.2 has a get
> version call which is definitely not implemented properly as after
> setting the compatible to 0.2 I get the following:
> 
> [    0.000000] psci: PSCIv65535.65535 detected in firmware.
> 
> Which is obviously not right.

Indeed. That's a bloody -1 returned by the firmware. Quality
implementation, as usual...

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.