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From: Arnd Bergmann <arnd@arndb.de>
To: Marc Zyngier <maz@kernel.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
	linux-pci <linux-pci@vger.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>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Rob Herring <robh@kernel.org>, Clint Sbisa <csbisa@amazon.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	Sunil Muthuswamy <sunilmut@microsoft.com>
Subject: Re: [RFC 1/2] arm64: PCI: Allow use arch-specific pci sysdata
Date: Sat, 20 Mar 2021 15:24:06 +0100	[thread overview]
Message-ID: <CAK8P3a2qATr7qAkPqkZW4aifb3rq6CPrrsEX=8XcjTk0j5aW0A@mail.gmail.com> (raw)
In-Reply-To: <87sg4qgdrd.wl-maz@kernel.org>

On Sat, Mar 20, 2021 at 2:23 PM Marc Zyngier <maz@kernel.org> wrote:
>
> On Sat, 20 Mar 2021 13:03:13 +0000,
> Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > On Sat, Mar 20, 2021 at 1:54 PM Marc Zyngier <maz@kernel.org> wrote:
> > > On Fri, 19 Mar 2021 21:12:46 +0000,
> > >
> > > Having an optional callback to host bridges to obtain the MSI domain
> > > may be possible in some cases though (there might be a chicken/egg
> > > problem for some drivers though...).
> >
> > I would expect that the host bridge driver can find the MSI domain
> > at probe time and just add a pointer into the pci_host_bridge
> > structure.
>
> In most cases, it doesn't implement it itself, and I'd be reluctant to
> duplicate information that can already be retrieved from somewhere
> else in a generic way (i.e. no PCI specific).

At the moment, the information is retried through a maze of different
functions, and already duplicated in both the pci_host_bridge and the
pci_bus structures.  If we can change everything to use
CONFIG_GENERIC_MSI_IRQ_DOMAIN, then most of that code
can probably just go away, leaving only the part in the phb.

       Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Marc Zyngier <maz@kernel.org>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	 Bjorn Helgaas <bhelgaas@google.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	 Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
	linux-pci <linux-pci@vger.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>,
	 Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Rob Herring <robh@kernel.org>,  Clint Sbisa <csbisa@amazon.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	 Sunil Muthuswamy <sunilmut@microsoft.com>
Subject: Re: [RFC 1/2] arm64: PCI: Allow use arch-specific pci sysdata
Date: Sat, 20 Mar 2021 15:24:06 +0100	[thread overview]
Message-ID: <CAK8P3a2qATr7qAkPqkZW4aifb3rq6CPrrsEX=8XcjTk0j5aW0A@mail.gmail.com> (raw)
In-Reply-To: <87sg4qgdrd.wl-maz@kernel.org>

On Sat, Mar 20, 2021 at 2:23 PM Marc Zyngier <maz@kernel.org> wrote:
>
> On Sat, 20 Mar 2021 13:03:13 +0000,
> Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > On Sat, Mar 20, 2021 at 1:54 PM Marc Zyngier <maz@kernel.org> wrote:
> > > On Fri, 19 Mar 2021 21:12:46 +0000,
> > >
> > > Having an optional callback to host bridges to obtain the MSI domain
> > > may be possible in some cases though (there might be a chicken/egg
> > > problem for some drivers though...).
> >
> > I would expect that the host bridge driver can find the MSI domain
> > at probe time and just add a pointer into the pci_host_bridge
> > structure.
>
> In most cases, it doesn't implement it itself, and I'd be reluctant to
> duplicate information that can already be retrieved from somewhere
> else in a generic way (i.e. no PCI specific).

At the moment, the information is retried through a maze of different
functions, and already duplicated in both the pci_host_bridge and the
pci_bus structures.  If we can change everything to use
CONFIG_GENERIC_MSI_IRQ_DOMAIN, then most of that code
can probably just go away, leaving only the part in the phb.

       Arnd

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-03-20 14:25 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19 16:19 [RFC 0/2] PCI: Introduce pci_ops::use_arch_sysdata Boqun Feng
2021-03-19 16:19 ` Boqun Feng
2021-03-19 16:19 ` [RFC 1/2] arm64: PCI: Allow use arch-specific pci sysdata Boqun Feng
2021-03-19 16:19   ` Boqun Feng
2021-03-19 21:12   ` Bjorn Helgaas
2021-03-19 21:12     ` Bjorn Helgaas
2021-03-20 12:54     ` Marc Zyngier
2021-03-20 12:54       ` Marc Zyngier
2021-03-20 13:03       ` Arnd Bergmann
2021-03-20 13:03         ` Arnd Bergmann
2021-03-20 13:23         ` Marc Zyngier
2021-03-20 13:23           ` Marc Zyngier
2021-03-20 14:24           ` Arnd Bergmann [this message]
2021-03-20 14:24             ` Arnd Bergmann
2021-03-20 17:14             ` Marc Zyngier
2021-03-20 17:14               ` Marc Zyngier
2021-03-20 12:54     ` Arnd Bergmann
2021-03-20 12:54       ` Arnd Bergmann
2021-03-20 16:09       ` Arnd Bergmann
2021-03-20 16:09         ` Arnd Bergmann
2021-03-29 14:32         ` Boqun Feng
2021-03-29 14:32           ` Boqun Feng
2021-03-29 14:43           ` Arnd Bergmann
2021-03-29 14:43             ` Arnd Bergmann
2021-03-20 12:52   ` Arnd Bergmann
2021-03-20 12:52     ` Arnd Bergmann
2021-03-19 16:19 ` [RFC 2/2] PCI: hv: Tell PCI core arch-specific sysdata is used Boqun Feng
2021-03-19 16:19   ` Boqun Feng
2021-03-19 19:04 ` [RFC 0/2] PCI: Introduce pci_ops::use_arch_sysdata Bjorn Helgaas
2021-03-19 19:04   ` Bjorn Helgaas

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