On Wed, Nov 06, 2024 at 10:17:47AM +0000, Matt Coster wrote: > On 05/11/2024 18:13, Conor Dooley wrote: > > On Tue, Nov 05, 2024 at 03:58:07PM +0000, Matt Coster wrote: > >> The current compatible strings are not specific enough to constrain the > >> hardware in devicetree. For example, the current "img,img-axe" string > >> refers to the entire family of Series AXE GPUs. The more specific > >> "img,img-axe-1-16m" string refers to the AXE-1-16M GPU which, unlike the > >> rest of its family, only uses a single power domain. > > > > That's not true, you could apply the rules using the ti,am62-gpu > > compatible, no? > > The intent here is to draw a line between properties inherent to the IP > core and choices made by the silicon vendor at integration time. The > number of power domains is a property of the IP core, whereas the > decision to use one or three clocks (next patch) is a vendor choice. That's a different argument than the one in your commit message, but I will accept it. > >> Work is currently underway to add support for volcanic-based Imagination > >> GPUs; also add a generic top-level "img,img-rogue" compatible string to > >> allow for simpler differentiation in devicetrees. > > > > This makes no sense, how does adding another fallback compatible make > > it simpler? I have to assume that this means there will be geothermally > > powered axes in the future and you want to tell the difference between > > them and those pesky rogue axes that chop the heads off of naughty > > children? > > The intent is to add Volcanic bindings in img,powervr-volcanic.yaml, but > the split between Rogue and Volcanic is... a bit weird. The BXS-4-64 > we're adding support for here is Rogue but, for example, the BXS-32-1024 > is Volcanic. I figured it would be nice to be able to grok from the > devicetree which architecture a core is using without having to refer > back to the bindings. So not geothermally powered axes, but it was the rationale. > The primary differentiator from a dt perspective is power topology. In > Rogue, there are few (poorly named) power domains. Volcanic has (a) > better domain names and (b) typically more granularity in domains, > leading to actual dependency trees we need to care about besides the > trivial A->B->... in Rogue. Please add that detail to the commit message. Not all of it, but the bits in the first paragraph. Cheers, Conor.
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