On 10/23/2024 11:27 PM, Krzysztof Kozlowski wrote: > On 23/10/2024 14:22, Raj Kumar Bhagat wrote: >> The above three blocks represent the QCN9274 WiFi devices connected to their >> respective PCI slots. The dotted line represents the WSI connection that connects >> these three devices together. Hence, the WSI interface is part of the QCN9274 device. >> >> To describe this WSI hardware connection in the device tree, we are adding three >> properties inside the WSI object: >> >> 1. qcom,wsi-group-id: >> In the above diagram, we have one WSI connection connecting all three devices. >> Hence, “qcom,wsi-group-id” for all three devices can be 0. >> >> This cannot be implied by the compatible property, as explained below: >> Let’s take the case of a platform that can have four QCN9274 WiFi devices. Below >> is one possibility of a WSI connection: >> >> +-------+ +-------+ +-------+ +-------+ >> | pcie2 | | pcie3 | | pcie1 | | pcie0 | >> | | | | | | | | >> +---->| wsi |------>| wsi |--+ +-->| wsi |----->| wsi |----+ >> | | idx 0 | | idx 1 | | | | idx 0 | | idx 1 | | >> | +-------+ +-------+ | | +-------+ +-------+ | >> +--------------------------------+ +-------------------------------+ >> >> In this case, QCN9274 devices connected in PCIe2 and PCIe3 will have the same >> “qcom,wsi-group-id”. This group-id will be different from the “qcom,wsi-group-id” >> of QCN9274 devices connected at PCIe1 and PCIe0. > Thanks, this explains why group-id cannot be same... > >> 2. qcom,wsi-index: >> This is a unique identifier of the device within the same group. The value of >> wsi-idx is represented in both the above cases (RDP433 and the 4 WiFi device >> platform) in the diagram itself. > But still any device-indexing is in general not accepted (and was > mentioned during reviews multiple times). > > This looks like circular list, so phandle will be enough. You only need > to mark devices being part of the same chain. > > Actually graph with endpoints would be more suitable, assuming above > diagram represents connections. > Thanks for suggesting "graph will endpoints" approach for representing WSI connections. I will check on this and come back. > Please include that diagram in binding description. > Sure will include the above diagram in next version. >> 3. qcom,wsi-num-devices: >> Represents the number of devices connected through WSI within the same WSI group to >> which the device belongs. >> >> In the case of RDP433, all devices will have this number as 3. >> For the second example with four WiFi devices but with two WSI connections, the >> value of “qcom,wsi-num-devices” for each device will be 2. > Not needed, just iterate over the graph children. Thanks, based on "graph with endpoints" implementation will have this as well.
