From: Boqun Feng <boqun.feng@gmail.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: "Bjorn Helgaas" <bhelgaas@google.com>,
"Arnd Bergmann" <arnd@arndb.de>, "Marc Zyngier" <maz@kernel.org>,
"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>,
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: Re: [RFC v5 1/8] PCI: Introduce domain_nr in pci_host_bridge
Date: Wed, 21 Jul 2021 08:57:17 +0800 [thread overview]
Message-ID: <YPdw7YMXyFoHDhq4@boqun-archlinux> (raw)
In-Reply-To: <20210720224925.GA137627@bjorn-Precision-5520>
On Tue, Jul 20, 2021 at 05:49:25PM -0500, Bjorn Helgaas wrote:
> On Tue, Jul 20, 2021 at 09:44:22PM +0800, Boqun Feng wrote:
> > Currently we retrieve the PCI domain number of the host bridge from the
> > bus sysdata (or pci_config_window if PCI_DOMAINS_GENERIC=y). Actually
> > we have the information at PCI host bridge probing time, and it makes
> > sense that we store it into pci_host_bridge. One benefit of doing so is
> > the requirement for supporting PCI on Hyper-V for ARM64, because the
> > host bridge of Hyper-V doesn't have pci_config_window, whereas ARM64 is
> > a PCI_DOMAINS_GENERIC=y arch, so we cannot retrieve the PCI domain
> > number from pci_config_window on ARM64 Hyper-V guest.
> >
> > As the preparation for ARM64 Hyper-V PCI support, we introduce the
> > domain_nr in pci_host_bridge and a sentinel value to allow drivers to
> > set domain numbers properly at probing time. Currently
> > CONFIG_PCI_DOMAINS_GENERIC=y archs are only users of this
> > newly-introduced field.
> >
> > Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
>
> Once all the issues are ironed out, Lorenzo should probably merge this
> since it's primarily Hyper-V stuff, but I'm OK with this part:
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>
Thanks!
> But fix the comment issue below.
>
Just send a v5.1 for this patch with the comment fixed and your
Acked-by.
Regards,
Boqun
> > ---
> > drivers/pci/probe.c | 6 +++++-
> > include/linux/pci.h | 10 ++++++++++
> > 2 files changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 79177ac37880..60c50d4f156f 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -594,6 +594,7 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
> > bridge->native_pme = 1;
> > bridge->native_ltr = 1;
> > bridge->native_dpc = 1;
> > + bridge->domain_nr = PCI_DOMAIN_NR_NOT_SET;
> >
> > device_initialize(&bridge->dev);
> > }
> > @@ -898,7 +899,10 @@ static int pci_register_host_bridge(struct pci_host_bridge *bridge)
> > bus->ops = bridge->ops;
> > bus->number = bus->busn_res.start = bridge->busnr;
> > #ifdef CONFIG_PCI_DOMAINS_GENERIC
> > - bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
> > + if (bridge->domain_nr == PCI_DOMAIN_NR_NOT_SET)
> > + bus->domain_nr = pci_bus_find_domain_nr(bus, parent);
> > + else
> > + bus->domain_nr = bridge->domain_nr;
> > #endif
> >
> > b = pci_find_bus(pci_domain_nr(bus), bridge->busnr);
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index 540b377ca8f6..2c413a64d168 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -526,6 +526,15 @@ static inline int pci_channel_offline(struct pci_dev *pdev)
> > return (pdev->error_state != pci_channel_io_normal);
> > }
> >
> > +/*
> > +* Currently in ACPI spec, for each PCI host bridge, PCI Segment Group number is
> > +* limited to a 16-bit value, therefore (int)-1 is not a valid PCI domain number,
> > +* and can be used as a sentinel value indicating >domain_nr is not set by the
> > +* driver (and CONFIG_PCI_DOMAINS_GENERIC=y archs will set it with
> > +* pci_bus_find_domain_nr()).
> > +*/
>
> Fix comment indentation (follow style of other comments in this file).
>
> s/>domain_nr/->domain_nr/
>
> > +#define PCI_DOMAIN_NR_NOT_SET (-1)
> > +
> > struct pci_host_bridge {
> > struct device dev;
> > struct pci_bus *bus; /* Root bus */
> > @@ -533,6 +542,7 @@ struct pci_host_bridge {
> > struct pci_ops *child_ops;
> > void *sysdata;
> > int busnr;
> > + int domain_nr;
> > struct list_head windows; /* resource_entry */
> > struct list_head dma_ranges; /* dma ranges resource list */
> > u8 (*swizzle_irq)(struct pci_dev *, u8 *); /* Platform IRQ swizzler */
> > --
> > 2.30.2
> >
next prev parent reply other threads:[~2021-07-21 0:59 UTC|newest]
Thread overview: 14+ 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 ` [RFC v5 1/8] PCI: Introduce domain_nr in pci_host_bridge Boqun Feng
2021-07-20 22:49 ` Bjorn Helgaas
2021-07-21 0:57 ` Boqun Feng [this message]
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 ` [RFC v5 3/8] arm64: PCI: Restructure pcibios_root_bridge_prepare() Boqun Feng
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 ` [RFC v5 6/8] PCI: hv: Set ->domain_nr of pci_host_bridge at probing time 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 ` [RFC v5 8/8] PCI: hv: Turn on the host bridge probing on ARM64 Boqun Feng
2021-07-20 14:38 ` Marc Zyngier
2021-07-20 14:59 ` Boqun Feng
2021-07-20 15:53 ` Marc Zyngier
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