On Mon, Mar 10, 2025 at 01:10:25PM +0000, Matt Coster wrote: > The first compatible strings added for the AXE-1-16M are not sufficient to > accurately describe all the IMG Rogue GPUs. The current "img,img-axe" > string refers to the entire family of Series AXE GPUs, but this is > primarily a marketing term and does not denote a level of hardware > similarity any greater than just "Rogue". > > The more specific "img,img-axe-1-16m" string refers to individual AXE-1-16M > GPU. For example, unlike the rest of the Series AXE GPUs, the AXE-1-16M > only uses a single power domain. > > The situation is actually slightly worse than described in the first > paragraph, since many "series" (such as Series BXS found in the TI AM68 > among others and added later in this series) contain cores with both Rogue > and Volcanic architectures. > > Besides attempting to move away from vague groupings defined only > by marketing terms, we want to draw a line between properties inherent to > the IP core and choices made by the silicon vendor at integration time. > For instance, the number of power domains is a property of the IP core, > whereas the decision to use one or multiple clocks is a vendor one. > > In the original compatible strings, we must use "ti,am62-gpu" to constrain > both of these properties since the number of power domains cannot be fixed > for "img,img-axe". > > Work is currently underway to add support for volcanic-based Imagination > GPUs, for which bindings will be added in "img,powervr-volcanic.yaml". > As alluded to previously, the split between rogue and volcanic cores is > non-obvious at times, so add a generic top-level "img,img-rogue" compatible > string here to allow for simpler differentiation in devicetrees without > referring back to the bindings. > > The currently supported GPU (AXE-1-16M) only requires a single power > domain. Subsequent patches will add support for BXS-4-64 MC1, which has > two power domains. Add infrastructure now to allow for this. > > Also allow the dma-coherent property to be added to IMG Rogue GPUs, which > are DMA devices. The decision for coherency is made at integration time and > this property should be applied wherever it accurately describes the > vendor integration. > > Note that the new required properties for power domains are conditional on > the new base compatible string to avoid an ABI break. > > Signed-off-by: Matt Coster <matt.coster@xxxxxxxxxx> > --- > Changes in v3: > - Remove unnecessary example > - Remove second power domain details, add these where they're used instead > - Avoid ABI breaks by limiting new required properties to new compatible > strings and making all binding changes in a single patch. > - Links to v2: > https://lore.kernel.org/r/20241118-sets-bxs-4-64-patch-v1-v2-1-3fd45d9fb0cf@xxxxxxxxxx > https://lore.kernel.org/r/20241118-sets-bxs-4-64-patch-v1-v2-3-3fd45d9fb0cf@xxxxxxxxxx > https://lore.kernel.org/r/20241118-sets-bxs-4-64-patch-v1-v2-4-3fd45d9fb0cf@xxxxxxxxxx > --- > .../devicetree/bindings/gpu/img,powervr-rogue.yaml | 43 ++++++++++++++++++---- > 1 file changed, 36 insertions(+), 7 deletions(-) > > diff --git a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml > index 256e252f8087fa0d6081f771a01601d34b66fe19..5c16b2881447c9cda78e5bb46569e2f675d740c4 100644 > --- a/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml > +++ b/Documentation/devicetree/bindings/gpu/img,powervr-rogue.yaml > @@ -12,10 +12,20 @@ maintainers: > > properties: > compatible: > - items: > - - enum: > - - ti,am62-gpu > - - const: img,img-axe # IMG AXE GPU model/revision is fully discoverable > + oneOf: > + - items: > + - enum: > + - ti,am62-gpu > + - const: img,img-axe-1-16m > + - const: img,img-rogue That's still ABI break. You got here NAK. You ust preserve img,img-axe. Your marketing troubles do not concern Linux. > + > + # This legacy combination of compatible strings was introduced early on > + # before the more specific GPU identifiers were used. > + - items: > + - enum: > + - ti,am62-gpu > + - const: img,img-axe > + deprecated: true > > reg: > maxItems: 1 > @@ -34,8 +44,13 @@ properties: > interrupts: > maxItems: 1 > > - power-domains: > - maxItems: 1 > + power-domains: true No, widest constraints always stay here. > + > + power-domain-names: > + items: > + - const: a That's not a useful name. Are you sure that datasheet calls it power domain A? > + > + dma-coherent: true Best regards, Krzysztof
