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Date: Thu, 25 Apr 2013 11:12:54 +0100
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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To: Will Deacon <will.deacon@arm.com>
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Subject: Re: [PATCH v8 1/2] arm: introduce psci_smp_ops
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On Thu, 25 Apr 2013, Will Deacon wrote:
> > +/*
> > + * cpu_suspend   Suspend the execution on a CPU
> > + * @state        we don't currently describe affinity levels, so just pass 0.
> > + * @entry_point  the first instruction to be executed on return
> > + * returns 0  success, < 0 on failure
> > + *
> > + * cpu_off       Power down a CPU
> > + * @state        we don't currently describe affinity levels, so just pass 0.
> > + * no return on successful call
> > + *
> > + * cpu_on        Power up a CPU
> > + * @cpuid        cpuid of target CPU, as from MPIDR
> > + * @entry_point  the first instruction to be executed on return
> > + * returns 0  success, < 0 on failure
> > + *
> > + * migrate       Migrate the context to a different CPU
> > + * @cpuid        cpuid of target CPU, as from MPIDR
> > + * returns 0  success, < 0 on failure
> > + *
> > + */
> 
> Can you move these comments into psci-smp.c please? They're really specific
> to the implementation there, and if we put them in a header we're lying to
> ourselves about the parameters actually described by the PSCI specification.

You have a good point about the PSCI spec.

However from the Linux POV these comments should regard the functions
exported by psci_operations, not the firmware interface, this is why I
think it makes sense to keep them in psci.h.
What we are saying is for example that psci_operations.cpu_on returns 0
on success and < 0 on failure, and it takes a cpuid and an entry point
as parameters. We are not saying anything about the firmware interface.

Maybe I should add at the top:

"psci_operations functions and parameters, might different from the
firmware interface:"