From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liviu Dudau Subject: Re: [PATCH] PCI: add missing DT binding for linux,pci-domain property Date: Thu, 6 Nov 2014 15:30:51 +0000 Message-ID: <20141106153051.GU8916@e106497-lin.cambridge.arm.com> References: <1415101660-26450-1-git-send-email-l.stach@pengutronix.de> <20141105231743.GI6168@google.com> <20141106100518.GI8916@e106497-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Content-Disposition: inline Sender: linux-pci-owner@vger.kernel.org To: Rob Herring Cc: Bjorn Helgaas , Lucas Stach , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , "devicetree@vger.kernel.org" , "linux-pci@vger.kernel.org" List-Id: devicetree@vger.kernel.org On Thu, Nov 06, 2014 at 02:57:35PM +0000, Rob Herring wrote: > On Thu, Nov 6, 2014 at 4:05 AM, Liviu Dudau wro= te: > > On Wed, Nov 05, 2014 at 11:17:43PM +0000, Bjorn Helgaas wrote: > >> On Tue, Nov 04, 2014 at 12:47:40PM +0100, Lucas Stach wrote: > >> > This property was added by 41e5c0f81d3e > >> > (of/pci: Add pci_get_new_domain_nr() and of_get_pci_domain_nr()) > >> > without the required binding documentation. As this property > >> > will be supported by a number of host bridge drivers going forwa= rd, > >> > add it to the common PCI binding doc. > >> > > >> > Signed-off-by: Lucas Stach > >> > >> I merged 41e5c0f81d3e through my tree, and I could merge something= like > >> this if a consensus develops with some acks. But I'll just let yo= u guys > >> handle it unless you poke me again. > > > > While I think the "linux,pci-domain" property *must* be documented,= I > > would like to get a consensus first on the usage. If we agree that > > the property is mandatory to all host bridge drivers that use OF th= en > > we need to patch existing drivers (partially done through Lorenzo's > > patches, but other arches are ignoring it). If we say all *new* dri= vers > > need to use it then we also need to come up with a strategy on how = to > > deal with old vs new school drivers. > > > > My preferred approach is the 3rd way: "linux,pci-domain" becomes pa= rt of > > the core PCI infrastructure (and we find the common ground with ACP= I). > > That way the host bridge drivers don't have to do anything, but the= DT > > creators have to specify a value. >=20 > I'm okay with it being in the core. It was the mixture of using the > property and automatic numbering that I had issues with. Any mixture > whether in DT or in drivers should be an error. Also, I think having = a > mixture of root bus host drivers would be rare, so I'm not too > concerned about some drivers supporting the property and others not. > In any case, these issues are all with the kernel and not really the > concern for the binding. For the binding, simply all hosts set the > domain or none of them do. Repeating what you've said to verify my understanding: you are OK with the "linux,pci-domain" being handled in the PCI framework and mandatory to all OF-based host bridges and architectures. Failure to include the property should be an error and no host bridge driver should defaul= t to the auto-generation of domain numbers. Is that correct? Thanks, Liviu >=20 > Rob >=20 --=20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- =C2=AF\_(=E3=83=84)_/=C2=AF