On Tue, Feb 20, 2024 at 08:41:25AM +0100, Johan Hovold wrote: > On Fri, Feb 16, 2024 at 10:24:06PM +0530, Manivannan Sadhasivam wrote: > > msi-map-mask is definitely needed as it would allow all the devices under the > > same bus to reuse the MSI identifier. Currently, excluding this property will > > not cause any issue since there is a single device under each bus. But we cannot > > assume that is going to be the case on all boards. > > Are you saying that there is never a use case for an identity mapping? > Just on Qualcomm hardware or in general? > > It looks like we have a fairly large number of mainline devicetrees that > do use an identity mapping here (i.e. do not specify 'msi-map-mask') and > the binding document also has an explicit example of this. > > Documentation/devicetree/bindings/pci/pci-msi.txt The above should have said "linear mapping" as the msi-base is not always identical to the rid-base, but you get the point. Johan
