From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liviu Dudau Subject: Re: [PATCH v8 6/9] pci: Introduce a domain number for pci_host_bridge. Date: Fri, 11 Jul 2014 10:30:07 +0100 Message-ID: <20140711093007.GN6501@e106497-lin.cambridge.arm.com> References: <1404240214-9804-1-git-send-email-Liviu.Dudau@arm.com> <1404240214-9804-7-git-send-email-Liviu.Dudau@arm.com> <20140708005954.GC22939@google.com> <20140708104655.GC6501@e106497-lin.cambridge.arm.com> <20140708224847.GC4980@e106497-lin.cambridge.arm.com> <20140710094758.GA6501@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: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bjorn Helgaas Cc: linux-pci , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Arnd Bergmann , linaro-kernel , Tanmay Inamdar , Grant Likely , Sinan Kaya , Jingoo Han , Kukjin Kim , Suravee Suthikulanit , LKML , Device Tree ML , LAKML List-Id: devicetree@vger.kernel.org On Thu, Jul 10, 2014 at 11:36:10PM +0100, Bjorn Helgaas wrote: > On Thu, Jul 10, 2014 at 3:47 AM, Liviu Dudau wr= ote: >=20 > > I don't see a way out of adding new PCI interfaces if we want to ha= ve support in > > the PCI framework for unifying existing architectures. Of course, t= here is the painful > > alternative of changing the existing APIs and fixing arches in one = go, but like you've > > said is going to be messy. I don't think I (or the people and compa= nies wanting PCIe > > on arm64) should cop out and pick a quick fix that adds sysdata str= ucture into arm64 > > just to avoid new APIs, as this is not going to help anyone in long= term. What I can > > do is to create a set of parallel APIs for pci_{scan,create}_root_b= us() that take > > a pci_host_bridge pointer and start converting architectures one by= one to that API > > while deprecating the existing one. That way we can add arm64 easil= y as it would be > > the first architecture to use new code without breaking things *and= * we provide a > > migration path. >=20 > A lot of the v7 discussion was about pci_register_io_range(). I > apologize, because I think I really derailed things there and it was > unwarranted. Arnd was right that migrating other arches should be a > separate effort. I *think* I was probably thinking about the proposa= l > of adding pci_create_root_bus_in_domain(), and my reservations about > that got transferred to the pci_register_io_range() discussion. In > any case, I'm completely fine with pci_register_io_range() now. >=20 > Most of the rest of the v7 discussion was about "Introduce a domain > number for pci_host_bridge." I think we should add arm64 using the > existing pci_scan_root_bus() and keep the domain number in the arm64 > sysdata structure like every other arch does. Isn't that feasible? > We can worry about domain unification later. Thanks! I'm really not that keen to add sysdata support in the arch code as it requires initialisation code that I have tried to eliminate. What I'm going to suggest for my v9 is a parallel set of APIs that arm64 will be the first to use without changing the existing pci_{scan,create}_bus= () functions and then the conversion process will migrate arches to the ne= w API. Best regards, Liviu >=20 > I haven't followed closely enough to know what other objections peopl= e had. >=20 > Bjorn >=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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html