On Tue, Jun 26, 2012 at 11:41:43AM -0600, Stephen Warren wrote: > On 06/26/2012 08:02 AM, Terje Bergström wrote: > > On 26.06.2012 16:41, Thierry Reding wrote: > > > >> On Tue, Jun 26, 2012 at 04:01:05PM +0300, Terje Bergström wrote: > >>> 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? > >>> Either way is fine for me. The full addresses are more familiar to me as > >>> we tend to use them internally. > > > >> 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
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