From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marc Zyngier <marc.zyngier@arm.com>
Date: Mon, 10 Nov 2014 13:36:49 +0000
Subject: [U-Boot] ARM: PSCI 0.1 vs 0.2
In-Reply-To: <5460BCE0.2020301@siemens.com>
References: <5460B4B5.2060602@siemens.com> <5460B8E8.9070706@arm.com>
	<5460BCE0.2020301@siemens.com>
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On 10/11/14 13:25, Jan Kiszka wrote:
> On 2014-11-10 14:08, Marc Zyngier wrote:
>> On 10/11/14 12:51, Jan Kiszka wrote:
>>> Hi Marc,
>>>
>>> what is the motivation to expose a PSCI 0.1 interface in U-boot, instead
>>> of 0.2? Support for preexisting users of 0.1? The kernel seems to be
>>> happy with both, and I'm now wondering if we should actually add the
>>> legacy version to Jailhouse as well (I hope we can avoid this).
>>
>> The initial rational was simple: at the time this code was written, the
>> 0.2 spec still in review, and nobody was implementing it. Supporting 0.1
>> was the only viable use-case.
>>
>>> Still studying the logic: Is it possible to provide both interfaces, and
>>> would it make sense?
>>
>> Supporting both is very easy. Just output the 0.2 function numbers that
>> actually make sense for 0.1 and have both compatible strings.
> 
> Ah, cool - parameters and return values of, say, CPU_ON/OFF are
> compatible across both versions?

That was the idea of the spec (broadly compatible across revisions...).

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...