Re: [PATCH 2/2] arm64: dts: realtek: Add RTD1319 SoC and Realtek PymParticle EVB

From: Robin Murphy <robin.murphy@arm.com>
To: "Andreas Färber" <afaerber@suse.de>, "James Tai" <james.tai@realtek.com>
Cc: mark.rutland@arm.com, devicetree@vger.kernel.org,
	linux-realtek-soc@lists.infradead.org,
	linux-kernel@vger.kernel.org, robh+dt@kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Subject: Re: [PATCH 2/2] arm64: dts: realtek: Add RTD1319 SoC and Realtek PymParticle EVB
Date: Thu, 5 Dec 2019 12:10:35 +0000	[thread overview]
Message-ID: <c2703787-2d0b-4d78-f4e3-8b77ba636bb4@arm.com> (raw)
In-Reply-To: <4040ffcf-5c54-fb44-b0a8-ce0c8c21b93f@suse.de>

On 2019-12-05 10:58 am, Andreas Färber wrote:
[...]
>> +	arm_pmu: pmu {
>> +		compatible = "arm,armv8-pmuv3";
>> +		interrupts = <GIC_PPI 7 IRQ_TYPE_LEVEL_LOW>;
>> +		interrupt-affinity = <&cpu0>, <&cpu1>, <&cpu2>,
>> +			<&cpu3>;
>> +	};
> 
> @Robin, is this single PPI interrupt better than previous single SPI?

Yes, a PPI is ideal (since it allows core to see its own local interrupt).

> Is "arm,armv8-pmuv3" the correct one to use for Cortex-A55? There's no
> "arm,cortex-a55-pmu" binding - is that still in the works?

Hmm, I had thought that had been done already, but apparently not. Looks 
like it's high time for another round of event map updates for the 
latest Cortex and Neoverse cores, so I guess I'll add that to our 
backlog internally - although the PMU events should be in the public 
TRMs so if anyone else *did* fancy ploughing through them to spin 
patches they're always welcome to :)

In the meantime the generic PMUv3 compatible will at least expose the 
subset of mandatory architectural events, which is arguably more useful 
than nothing.

>> +
>> +	psci {
>> +		compatible = "arm,psci-1.0";
> 
> @Lorenzo: Same question as left unanswered for RTD1619:
> Should this be "arm,psci-1.0", "arm-psci-0.2"?
> 
> The YAML schema allows both, without clearly documenting which one shall
> be used in new DTs, and there's no psci-1.0 example either.

FWIW the age of the DT shouldn't really be relevant - it's a question of 
whether the platform's EL3 firmware actually implements the PSCI 1.0 (or 
later) spec, or is some fossilised binary based on the older version.

Robin.