[U-Boot] [PATCH 2/2] sun7i: Add PSCI v0.2 support

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2014-12-15 12:44, Hans de Goede wrote:
> Hi,
> 
> On 15-12-14 12:37, Jan Kiszka wrote:
>> This extends the PSCI support for the A20 to a dual v0.2 and v0.1
>> interface. Recent OSes will prefer v0.2, olders will still find the
>> original interface, just at v0.2 service IDs.
>>
>> In addition to the existing services, v0.2 requires us to implement both
>> system off and reset. At least Linux will make use of them in favor of
>> its own implementations and, thus, fail if they do not work.
> 
> Ugh, that may be a problem, as at least power off is highly SoC specific
> (different pmics, and newer pmics have a different bus) and somewhat board
> specific.

Yes, that was my first thought as well.

> 
> I think we may avoid adding any board specific stuff for now, since we
> only want PSCI support on A20 and later and the only boards I know
> of which are not using the standard axp pmics are all A10 / A13 boards,
> but this might come back to bite us in the future.

Good - so this is a conceptual ack for this patch?

> 
> Can't we just return -ENOTSUPPORTED or some such ?

Unfortunately not. I don't know what was the intention of the designed
of this spec regarding mandatory SYSTEM_OFF and SYSTEM_RESET support.
Both functions are not supposed to return at all, and the kernel panics
when you return from SYSTEM_OFF.

Jan

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