Re: [PATCH v2 3/3] firmware: scpi: add device power domain support using genpd

From: Sudeep Holla
Date: Fri Jun 17 2016 - 04:38:33 EST




On 17/06/16 09:19, Jon Medhurst (Tixy) wrote:
On Thu, 2016-06-16 at 18:59 +0100, Sudeep Holla wrote:

On 16/06/16 18:47, Jon Medhurst (Tixy) wrote:
On Thu, 2016-06-16 at 11:38 +0100, Sudeep Holla wrote:
[...]
+enum scpi_power_domain_state {
+ SCPI_PD_STATE_ON = 0,
+ SCPI_PD_STATE_OFF = 3,
+};

The SCPI doc defines the meaning of these numbers (0 and 3) in the 'Juno
specifics' chapter. So does these values need to come from device-tree
to allow for other hardware or SCP implementations?


Ah unfortunately true :(. I had not noticed that. But I would like to
check if this can be made as part of the standard protocol. Adding such
details to DT seems overkill and defeat of the whole purpose of the
standard protocol.

Well. it seems to me the 'standard protocol' is whatever the current
implementation of ARM's closed source SCP firmware is. It also seems to
me that people are making things up as they go along, without a clue as
to how to make things generic, robust and future proof.

Totally agree. There's an effort to come up with more standard version
of this involving partners/users soon. It's still under discussion and
the aim is to make it as good as PSCI. Let's see where it goes...

--
Regards,
Sudeep