On Wed, Feb 11, 2015 at 3:29 AM, Mark Rutland [off-list ref] wrote:

On Thu, Jan 29, 2015 at 03:58:42AM +0000, Suman Anna wrote:

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On 01/22/2015 12:56 PM, Mark Rutland wrote:

[..]

quoted

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That's the only way I would expect this to possibly remain a stable
over time, and it's the entire reason for #hwlock-cells, no?

How do you expect the other components sharing the hwspinlocks to be
described?

Yes indeed, this is what any of the clients will use on Linux. But
this is not necessarily the semantics for exchanging hwlocks with the
other processor(s) which is where the global id space comes into
picture.

I did try to consider that above. Rather than thinking about the
numbering as "global", think of it as unique within the a given pool
shared between processors. That's what the "poolN" names are about
above.

That way you can dynamically allocate within the pool and know that
Linux and the SW on the other processors will use the same ID. You can
have pools that span multiple hwlock hardware blocks, and you can have
multiple separate pools in operation at once.

Surely that covers the cases you care about?

If using names is clunky, we could instead have a pool-hwlocks property
for that purpose.

Just to make I understand your suggestion.

We would have the communication entity list all the potential hwlocks
(and gpios etc) that it can share and the key to be communicated would
then basically be the index in that list?

Like:
awesome-hub {
    pool-hwlocks = <&a 1>, <&a 3>, <&b 5>;
};

And a communicated "lock 2" would mean lock 3 from block a?


This would make it possible to describe what locks are available in
this "allocation pool" and would keep such allocation logic out from
the hwlock core - as the awesome-hub driver could simply trial and
error (with some logic) through the list.

Is this understanding correct?

Regards,
Bjorn