From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Tue, 7 Jun 2016 19:15:59 -0500 From: Bjorn Helgaas To: Tomasz Nowicki Subject: Re: [PATCH V8 5/9] pci, acpi: add acpi hook to assign domain number. Message-ID: <20160608001559.GD4759@localhost> References: <1464621262-26770-1-git-send-email-tn@semihalf.com> <1464621262-26770-6-git-send-email-tn@semihalf.com> MIME-Version: 1.0 In-Reply-To: <1464621262-26770-6-git-send-email-tn@semihalf.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: rafael@kernel.org, linux-pci@vger.kernel.org, will.deacon@arm.com, okaya@codeaurora.org, wangyijing@huawei.com, andrea.gallo@linaro.org, Lorenzo.Pieralisi@arm.com, linaro-acpi@lists.linaro.org, ddaney@caviumnetworks.com, linux-acpi@vger.kernel.org, robert.richter@caviumnetworks.com, liudongdong3@huawei.com, catalin.marinas@arm.com, Liviu.Dudau@arm.com, arnd@arndb.de, jcm@redhat.com, msalter@redhat.com, cov@codeaurora.org, mw@semihalf.com, linux-arm-kernel@lists.infradead.org, jchandra@broadcom.com, dhdang@apm.com, linux-kernel@vger.kernel.org, jeremy.linton@arm.com, hanjun.guo@linaro.org, Suravee.Suthikulpanit@amd.com Content-Type: text/plain; charset="us-ascii" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+bjorn=helgaas.com@lists.infradead.org List-ID: Hi Tomasz, On Mon, May 30, 2016 at 05:14:18PM +0200, Tomasz Nowicki wrote: > PCI core code provides a config option (CONFIG_PCI_DOMAINS_GENERIC) > that allows assigning the PCI bus domain number generically by > relying on device tree bindings, and falling back to a simple counter > when the respective DT properties (ie "linux,pci-domain") are not > specified in the host bridge device tree node. > > In a similar way, when a system is booted through ACPI, architectures > that are selecting CONFIG_PCI_DOMAINS_GENERIC (ie ARM64) require kernel > hooks to retrieve the domain number so that the PCI bus domain number > set-up can be handled seamlessly with DT and ACPI in generic core code > when CONFIG_PCI_DOMAINS_GENERIC is selected. > > Since currently it is not possible to retrieve a pointer to the PCI > host bridge ACPI device backing the host bridge from core PCI code > (which would allow retrieving the domain number in an arch agnostic > way through the ACPI _SEG method), an arch specific ACPI hook has to > be declared and implemented by all arches that rely on > CONFIG_PCI_DOMAINS_GENERIC to retrieve the domain number and set it > up in core PCI code. > > For the aforementioned reasons, this patch introduces a dummy > acpi_pci_bus_domain_nr() hook in preparation for per-arch implementation > of the same to retrieve the domain number on a per-arch basis when > the system boots through ACPI. > > For the sake of code clarity the current code implementing generic > domain number assignment (ie pci_bus_assign_domain_nr(), selected by > CONFIG_PCI_DOMAINS_GENERIC) is reshuffled so that the code implementing > the DT domain assignment function is stubbed out into a corresponding > helper, so that DT and ACPI functions are clearly separated in > preparation for arches acpi_pci_bus_domain_nr() implementations. > > Signed-off-by: Tomasz Nowicki > Signed-off-by: Lorenzo Pieralisi > --- > drivers/pci/pci.c | 11 +++++++++-- > include/linux/pci.h | 1 + > 2 files changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index eb431b5..2b52178 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -7,6 +7,7 @@ > * Copyright 1997 -- 2000 Martin Mares > */ > > +#include > #include > #include > #include > @@ -4941,7 +4942,7 @@ int pci_get_new_domain_nr(void) > } > > #ifdef CONFIG_PCI_DOMAINS_GENERIC > -void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) > +static int of_pci_bus_domain_nr(struct device *parent) Can we do a little cleanup before this patch? - pci_bus_assign_domain_nr() is only used inside drivers/pci, so maybe we move the prototype to drivers/pci/pci.h? - I don't really like the style of calling a function that internally assigns bus->domain_nr. Could we do something like this instead? int pci_bus_domain_nr(...) { ... return domain; } ... pci_create_root_bus(...) { ... b->domain_nr = pci_bus_domain_nr(...); That would be two new patches, if this makes sense. And this patch would only rename pci_bus_assign_domain_nr() to of_pci_bus_domain_nr() and add the pci_bus_domain_nr() wrapper. > { > static int use_dt_domains = -1; > int domain = -1; > @@ -4985,7 +4986,13 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) > domain = -1; > } > > - bus->domain_nr = domain; > + return domain; > +} > + > +void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) > +{ > + bus->domain_nr = acpi_disabled ? of_pci_bus_domain_nr(parent) : > + acpi_pci_bus_domain_nr(bus); > } > #endif > #endif > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 12349de..bba4053 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1390,6 +1390,7 @@ static inline int pci_domain_nr(struct pci_bus *bus) > { > return bus->domain_nr; > } > +static inline int acpi_pci_bus_domain_nr(struct pci_bus *bus) { return -1; } I would split the addition of acpi_pci_bus_domain_nr() to a separate patch and include the ARM64 definition in that same patch. That patch would only add this stub definition, the ARM64 definition, and the new call in pci_bus_domain_nr(). > void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent); > #else > static inline void pci_bus_assign_domain_nr(struct pci_bus *bus, > -- > 1.9.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel