From: Boqun Feng <boqun.feng@gmail.com> To: Bjorn Helgaas <bhelgaas@google.com>, Arnd Bergmann <arnd@arndb.de>, Marc Zyngier <maz@kernel.org> Cc: "Catalin Marinas" <catalin.marinas@arm.com>, "Will Deacon" <will@kernel.org>, "K. Y. Srinivasan" <kys@microsoft.com>, "Haiyang Zhang" <haiyangz@microsoft.com>, "Stephen Hemminger" <sthemmin@microsoft.com>, "Wei Liu" <wei.liu@kernel.org>, "Dexuan Cui" <decui@microsoft.com>, "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>, "Rob Herring" <robh@kernel.org>, "Krzysztof Wilczyński" <kw@linux.com>, "Boqun Feng" <boqun.feng@gmail.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, "Sunil Muthuswamy" <sunilmut@microsoft.com>, "Mike Rapoport" <rppt@kernel.org> Subject: [RFC v5 4/8] arm64: PCI: Support root bridge preparation for Hyper-V Date: Tue, 20 Jul 2021 21:44:25 +0800 [thread overview] Message-ID: <20210720134429.511541-5-boqun.feng@gmail.com> (raw) In-Reply-To: <20210720134429.511541-1-boqun.feng@gmail.com> Currently at root bridge preparation, the corresponding ACPI device will be set as the companion, however for a Hyper-V virtual PCI root bridge, there is no corresponding ACPI device, because a Hyper-V virtual PCI root bridge is discovered via VMBus rather than ACPI table. In order to support this, we need to make pcibios_root_bridge_prepare() work with cfg->parent being NULL. Use a NULL pointer as the ACPI device if there is no corresponding ACPI device, and this is fine because: 1) ACPI_COMPANION_SET() can work with the second parameter being NULL, 2) semantically, if a NULL pointer is set via ACPI_COMPANION_SET(), ACPI_COMPANION() (the read API for this field) will return NULL, and since ACPI_COMPANION() may return NULL, so users must have handled the cases where it returns NULL, and 3) since there is no corresponding ACPI device, it would be wrong to use any other value here. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> --- arch/arm64/kernel/pci.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index 5148ae242780..2276689b5411 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -90,7 +90,17 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge) return 0; cfg = bridge->bus->sysdata; - adev = to_acpi_device(cfg->parent); + + /* + * On Hyper-V there is no corresponding ACPI device for a root bridge, + * therefore ->parent is set as NULL by the driver. And set 'adev' as + * NULL in this case because there is no proper ACPI device. + */ + if (!cfg->parent) + adev = NULL; + else + adev = to_acpi_device(cfg->parent); + bus_dev = &bridge->bus->dev; ACPI_COMPANION_SET(&bridge->dev, adev); -- 2.30.2
WARNING: multiple messages have this Message-ID (diff)
From: Boqun Feng <boqun.feng@gmail.com> To: Bjorn Helgaas <bhelgaas@google.com>, Arnd Bergmann <arnd@arndb.de>, Marc Zyngier <maz@kernel.org> Cc: "Catalin Marinas" <catalin.marinas@arm.com>, "Will Deacon" <will@kernel.org>, "K. Y. Srinivasan" <kys@microsoft.com>, "Haiyang Zhang" <haiyangz@microsoft.com>, "Stephen Hemminger" <sthemmin@microsoft.com>, "Wei Liu" <wei.liu@kernel.org>, "Dexuan Cui" <decui@microsoft.com>, "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>, "Rob Herring" <robh@kernel.org>, "Krzysztof Wilczyński" <kw@linux.com>, "Boqun Feng" <boqun.feng@gmail.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org, "Sunil Muthuswamy" <sunilmut@microsoft.com>, "Mike Rapoport" <rppt@kernel.org> Subject: [RFC v5 4/8] arm64: PCI: Support root bridge preparation for Hyper-V Date: Tue, 20 Jul 2021 21:44:25 +0800 [thread overview] Message-ID: <20210720134429.511541-5-boqun.feng@gmail.com> (raw) In-Reply-To: <20210720134429.511541-1-boqun.feng@gmail.com> Currently at root bridge preparation, the corresponding ACPI device will be set as the companion, however for a Hyper-V virtual PCI root bridge, there is no corresponding ACPI device, because a Hyper-V virtual PCI root bridge is discovered via VMBus rather than ACPI table. In order to support this, we need to make pcibios_root_bridge_prepare() work with cfg->parent being NULL. Use a NULL pointer as the ACPI device if there is no corresponding ACPI device, and this is fine because: 1) ACPI_COMPANION_SET() can work with the second parameter being NULL, 2) semantically, if a NULL pointer is set via ACPI_COMPANION_SET(), ACPI_COMPANION() (the read API for this field) will return NULL, and since ACPI_COMPANION() may return NULL, so users must have handled the cases where it returns NULL, and 3) since there is no corresponding ACPI device, it would be wrong to use any other value here. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> --- arch/arm64/kernel/pci.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c index 5148ae242780..2276689b5411 100644 --- a/arch/arm64/kernel/pci.c +++ b/arch/arm64/kernel/pci.c @@ -90,7 +90,17 @@ int pcibios_root_bridge_prepare(struct pci_host_bridge *bridge) return 0; cfg = bridge->bus->sysdata; - adev = to_acpi_device(cfg->parent); + + /* + * On Hyper-V there is no corresponding ACPI device for a root bridge, + * therefore ->parent is set as NULL by the driver. And set 'adev' as + * NULL in this case because there is no proper ACPI device. + */ + if (!cfg->parent) + adev = NULL; + else + adev = to_acpi_device(cfg->parent); + bus_dev = &bridge->bus->dev; ACPI_COMPANION_SET(&bridge->dev, adev); -- 2.30.2 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-07-20 14:02 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-20 13:44 [RFC v5 0/8] PCI: hv: Support host bridge probing on ARM64 Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 13:44 ` [RFC v5 1/8] PCI: Introduce domain_nr in pci_host_bridge Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 22:49 ` Bjorn Helgaas 2021-07-20 22:49 ` Bjorn Helgaas 2021-07-21 0:57 ` Boqun Feng 2021-07-21 0:57 ` Boqun Feng 2021-07-20 13:44 ` [RFC v5 2/8] PCI: Support populating MSI domains of root buses via bridges Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 13:44 ` [RFC v5 3/8] arm64: PCI: Restructure pcibios_root_bridge_prepare() Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 13:44 ` Boqun Feng [this message] 2021-07-20 13:44 ` [RFC v5 4/8] arm64: PCI: Support root bridge preparation for Hyper-V Boqun Feng 2021-07-20 13:44 ` [RFC v5 5/8] PCI: hv: Generify PCI probing Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 13:44 ` [RFC v5 6/8] PCI: hv: Set ->domain_nr of pci_host_bridge at probing time Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 13:44 ` [RFC v5 7/8] PCI: hv: Set up MSI domain at bridge " Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 13:44 ` [RFC v5 8/8] PCI: hv: Turn on the host bridge probing on ARM64 Boqun Feng 2021-07-20 13:44 ` Boqun Feng 2021-07-20 14:38 ` Marc Zyngier 2021-07-20 14:38 ` Marc Zyngier 2021-07-20 14:59 ` Boqun Feng 2021-07-20 14:59 ` Boqun Feng 2021-07-20 15:53 ` Marc Zyngier 2021-07-20 15:53 ` Marc Zyngier
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