On Tue, Jun 26, 2012 at 11:41:43AM -0600, Stephen Warren wrote:

On 06/26/2012 08:02 AM, Terje Bergström wrote:

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On 26.06.2012 16:41, Thierry Reding wrote:

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On Tue, Jun 26, 2012 at 04:01:05PM +0300, Terje Bergström wrote:

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We also assign certain host1x common resources per device by convention,
f.ex. sync points, channels etc. We currently encode that information in
the device node (3D uses sync point number X, 2D uses numbers Y and Z).
The information is not actually describing hardware, as it just
describes the convention, so I'm not sure if device tree is the proper
place for it.

Are they configurable? If so I think we should provide for them being
specified in the device tree. They are still hardware resources being
assigned to devices.

Yes, they're configurable, and there's nothing hardware specific in the
assignment of a sync point to a particular use. It's all just a software
agreement. That's why I'm a bit hesitant on putting it in device trees,
which are supposed to only describe hardware.

So I think that the DT can describe the existence of sync-points
(presumably include a node for the sync-point HW device if it's
separate). However, since the usage of each sync-point is entirely
arbitrary, that seems like something which should be either assigned
dynamically at run-time, or at least managed/assigned in SW at runtime
somehow, rather than hard-coded into DT; it's more policy than HW.

The sync-points are part of the host1x device as I understand it. If
their usage is truly generic, then we can probably ignore them safely.
Maybe it'd make sense to carry a property that defines the number of
sync points available for the host1x hardware represented by the DT?

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Either way is fine for me. The full addresses are more familiar to me as
we tend to use them internally.

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Using the OF mechanism for translating the host1x bus addresses,
relative to the host1x base address, to CPU addresses seems "purer", but
either way should work fine.

I'll let you decide, as I don't have a strong opinion either way. I
guess whatever is the more common way wins.

I'd certainly prefer all the nodes to use the full/absolute address.
That way, the DT will exactly match the addresses in the documentation.

Okay, I'll leave the ranges property as it is now.

Thierry