Hi Rafael, Sorry once again on the delays...My email hygiene has been getting bad, so mail gets buried. On Fri, Jan 05, 2018 at 02:13:33AM +0100, Rafael J. Wysocki wrote: > On Friday, January 5, 2018 1:41:31 AM CET Brian Norris wrote: > > On Wed, Dec 27, 2017 at 01:57:07AM +0100, Rafael J. Wysocki wrote: > > > On Tuesday, December 26, 2017 2:06:47 AM CET JeffyChen wrote: > > > > On 12/26/2017 08:11 AM, Rafael J. Wysocki wrote: > > > > >> >+ > > > > >> >+ dn = pci_device_to_OF_node(ppdev); > > > > >> >+ if (!dn) > > > > >> >+ return 0; > > > > >> >+ > > > > >> >+ irq = of_irq_get_byname(dn, "wakeup"); > > > > > Why is this a property of the bridge and not of the device itself? > > > > Wait, isn't 'dn' the port node, not the bridge node? > > I may be confused about the structure you have in DT. Probably :) And my DT structure may not be correct. But it's easily available to review. See arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi: http://elixir.free-electrons.com/linux/v4.14.2/source/arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi#L705 It has a bridge->port->device nesting hierarchy. I'm not actually sure where this came from exactly, but I *thought* it was derived from the standard documentation: Documentation/devicetree/bindings/pci/pci.txt PCI Bus Binding to: IEEE Std 1275-1994 http://www.devicetree.org/open-firmware/bindings/pci/pci2_1.pdf I'm not so sure now... > In the device hierarchy PCIe ports are represented as bridges. But device hierarchy can be slightly different than DT hierarchy. In our case, pcie@0,0 seems to correspond to the port, but has no companion "device". Or maybe I'm really off-base. > > > > That is suggested by Brian, because in that way, the wakeup pin would > > > > not "tied to what exact device is installed (or no device, if it's a slot)." > > > > I believe my thinking has evolved a bit over time, and I definitely am > > not the one true authority on this. I'll explain my main concerns, and > > whatever solution resolves these concerns is fine with me. > > > > * I was primarily interested in avoiding handling WAKE# in the endpoint > > drivers (e.g., as mwifiex is today). > > OK, everybody on this thread is interested in that. :-) Sure :) > > * I was also interested in not having to redefine a new DT device > > node (with new "pciABCD,1234" compatible property) for each new device > > attached. That just won't work for removable cards. > > So if you make it the property of a bridge, it should be fine (as long > as the bridge itself is not removable). OK...in that case you've answered your question at the top: "Why is this a property of the bridge and not of the device itself?" I think Jeffy answered similarly, but this walked you through how *I* got to that conclusion, at least. > > I need to reread the rest of this thread a few times to really > > understand what Rafael and Tony are discussing. But I feel like some of > > this is still moving away from the second point above. > > > > > But I don't think it works when there are two devices using different WAKE# > > > interrupt lines under the same bridge. Or how does it work then? > > We seem to have agreed that this case needs to be neglected here. OK, I guess that's a reasonable conclusion. > The "wakeup-interrupt" property at the bridge level basically has to be defined > as the wakeup interrupt for all devices on the bus under the bridge. The only thing I'm at a loss for is whether this goes in (referring to rk3399-gru.dtsi) &pcie or &pci_rootport. I think some versions of this series have been aiming for the former, and some the latter. Brian
