On Wed, 2024-06-26 at 09:33 +0200, Krzysztof Kozlowski wrote: > > On 20/06/2024 10:48, Matthias Schiffer wrote: > > On Thu, 2024-06-20 at 10:29 +0200, Krzysztof Kozlowski wrote: > > > > > > > > > On 20/06/2024 10:26, Matthias Schiffer wrote: > > > > On Thu, 2024-06-20 at 09:24 +0200, Krzysztof Kozlowski wrote: > > > > > On 19/06/2024 13:24, Matthias Schiffer wrote: > > > > > > While the current Device Trees for TI EVMs configure the PRUSS Ethernet > > > > > > controller as a toplevel node with names like "icssg1-eth", allowing to > > > > > > make it a subnode of the ICSSG has a number of advantages: > > > > > > > > > > What is ICSSG? The sram or ti,prus from the ethernet schema? > > > > > > > > ICSSG (Industrial Communication Subsystem (Group?)) is the main device described by the > > > > ti,pruss.yaml binding (ICSS and PRUSS are different variants of similar IP cores); it is the > > > > container for the individual PRU, TXPRU and RTU cores which are referenced by the ti,prus > > > > node of the Ethernet schema. > > > > > > > > The entirety of PRU, TXPRU and RTU cores of one ICSSG, each with its own firmware, forms one > > > > Ethernet controller, which is not quite a hardware device, but also not a fully virtual software > > > > device. > > > > > > So it is not really child of ICSSG. > > > > > > > > > > > The Ethernet controller only exists through the various ICSS subcores, so it doesn't have an MMIO > > > > address of its own. As described, the existing Device Trees define it as a toplevel non-MMIO node; > > > > we propose to allow it as a non-MMIO child node of the ICSSG container instead. > > > > > > > > If you consider moving the ethernet node into the ICSSG node a bad approach, we will drop this patch > > > > and try to find a different solution to our issue (the Ethernet device staying in deferred state > > > > forever when the ICSSG node is disabled on Linux). > > > > > > Just disable the ethernet. That's the expected behavior, I don't get > > > what is the problem here. > > > > If the disabling happens as a fixup in the bootloader, it needs to know the name of the Ethernet > > controller node (or iterate through the DTB to find references to the disabled ICSSG node). > > Which is already solved for several such cases, including ethernet > devices? Aliases? > > > > > The name is currently not used for anything, and not specified in the binding doc; the example uses > > "ethernet", which is too unspecific, as there can be multiple ICSSG/PRUs, with each running a > > separate Ethernet controller. > > Use existing solutions - aliases. Understood. I'm not entirely happy that the bootloader needs to know that it is an Ethernet controller that is provided by the ICSSG, and there isn't a simple way to say "whatever kind of device that Linux's DTB loads into the ICSSG should be disabled". But I guess for most boards there is only a single kind of ICSSG firmware that is used anyways. So I'm going with the solution you propose for now. Best regards, Matthias > > > > > Existing Device trees use "icssgX-eth" for an Ethernet controller running on the ICSSG with label > > "&icssgX", but labels are a source concept and don't exist in the compiled DTB by default. > > > > I do have an idea for an alternative approach that does not need changes to the DT bindings: The PRU > > Ethernet driver could detect that the referenced ti,prus are disabled and not just waiting to be > > probed and then fail with ENODEV instead of EPROBE_DEFER. > > Sorry, but re-shuffling nodes into incorrect hardware description is not > the workaround for your problem. > > Best regards, > Krzysztof > -- TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany Amtsgericht München, HRB 105018 Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider https://www.tq-group.com/
