From: Andrew Murray <andrew.murray@arm.com>
To: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Arnd Bergmann <arnd@arndb.de>,
Stephen Warren <swarren@wwwdotorg.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
Grant Likely <grant.likely@secretlab.ca>,
"rob.herring@calxeda.com" <rob.herring@calxeda.com>,
Russell King <linux@arm.linux.org.uk>,
Bjorn Helgaas <bhelgaas@google.com>,
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
"devicetree-discuss@lists.ozlabs.org"
<devicetree-discuss@lists.ozlabs.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: [PATCH 10/14] PCI: tegra: Move PCIe driver to drivers/pci/host
Date: Mon, 14 Jan 2013 09:57:07 +0000 [thread overview]
Message-ID: <20130114095706.GA23467@arm.com> (raw)
In-Reply-To: <20130113095806.GA31966@avionic-0098.adnet.avionic-design.de>
On Sun, Jan 13, 2013 at 09:58:06AM +0000, Thierry Reding wrote:
> On Sat, Jan 12, 2013 at 09:12:25PM +0000, Arnd Bergmann wrote:
> > On Saturday 12 January 2013, Thierry Reding wrote:
> > > > I already hinted at that in one of the other subthreads. Having such a
> > > > multiplex would also allow the driver to be built as a module. I had
> > > > already thought about this when I was working on an earlier version of
> > > > these patches. Basically these would be two ops attached to the host
> > > > bridge, and the generic arch_setup_msi_irq() could then look that up
> > > > given the struct pci_dev that is passed to it and call this new per-
> > > > host bridge .setup_msi_irq().
> > >
> > > struct pci_ops looks like a good place to put these. They'll be
> > > available from each struct pci_bus, so should be easy to call from
> > > arch_setup_msi_irq().
> > >
> > > Any objections?
> > >
> >
> > struct pci_ops has a long history of being specifically about
> > config space read/write operations, so on the one hand it does
> > not feel like the right place to put interrupt specific operations,
> > but on the other hand, the name sounds appropriate and I cannot
> > think of any other place to put this, so it's fine with me.
> >
> > The only alternative I can think of is to introduce a new
> > structure next to it in struct pci_bus, but that feels a bit
> > pointless. Maybe Bjorn has a preference one way or the other.
>
> The name pci_ops is certainly generic enough. Also the comment above the
> structure declaration says "Low-level architecture-dependent routines",
> which applies to the MSI functions as well.
I've previously looked into this. It seems that architectures handle this
in different ways, some use vector tables, others use a multiplex and others
just let the end user implement the callback directly.
I've made an attempt to find a more common way. Though my implementation, which
I will try to share later today for reference provides a registration function
in drivers/pci/msi.c to provide implementations of the
(setup|teardown)_msi_irq(s) ops. This seems slightly better than the current
approach and doesn't break existing users - but is still ugly.
At present the PCI and MSI frameworks are largely uncoupled from each other and
so I was keen to not pollute PCI structures (e.g. pci_ops) with MSI ops. Just
because most PCI host bridges also provide MSI support I don't think there is a
reason why they should always come as a pair or be provided by the same chip.
Perhaps the solution is to support MSI controller drivers and a means to
associate them with PCI host controller drivers?
Andrew Murray
next prev parent reply other threads:[~2013-01-14 9:57 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-09 20:43 [PATCH 00/14] Rewrite Tegra PCIe driver Thierry Reding
2013-01-09 20:43 ` [PATCH 01/14] of/pci: Provide support for parsing PCI DT ranges property Thierry Reding
2013-01-11 0:06 ` Stephen Warren
2013-01-11 4:02 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 02/14] of/pci: Add of_pci_get_devfn() function Thierry Reding
2013-01-11 0:09 ` Stephen Warren
2013-01-11 4:06 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 03/14] of/pci: Add of_pci_get_bus() function Thierry Reding
2013-01-09 20:43 ` [PATCH 04/14] of/pci: Add of_pci_parse_bus_range() function Thierry Reding
2013-01-09 20:43 ` [PATCH 05/14] lib: Add I/O map cache implementation Thierry Reding
2013-01-09 21:19 ` Arnd Bergmann
2013-01-09 21:54 ` Thierry Reding
2013-01-09 22:10 ` Arnd Bergmann
2013-01-09 23:12 ` Stephen Warren
2013-01-09 23:17 ` Jason Gunthorpe
2013-01-10 7:19 ` Thierry Reding
2013-01-10 9:17 ` Arnd Bergmann
2013-01-10 10:25 ` Thierry Reding
2013-01-10 18:20 ` Jason Gunthorpe
2013-01-10 18:55 ` Thierry Reding
2013-01-10 19:03 ` Thierry Reding
2013-01-10 19:24 ` Jason Gunthorpe
2013-01-10 20:20 ` Thierry Reding
2013-01-10 21:06 ` Jason Gunthorpe
2013-01-16 10:18 ` Thierry Reding
2013-01-16 11:25 ` Russell King - ARM Linux
2013-01-16 11:52 ` Thierry Reding
2013-01-10 18:26 ` Arnd Bergmann
2013-01-10 18:57 ` Thierry Reding
2013-01-10 7:10 ` Thierry Reding
2013-01-09 21:28 ` Russell King - ARM Linux
2013-01-09 21:57 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 06/14] ARM: pci: Keep pci_common_init() around after init Thierry Reding
2013-02-05 20:41 ` Thierry Reding
2013-02-06 16:30 ` Russell King - ARM Linux
2013-02-06 19:35 ` Thierry Reding
2013-02-06 8:36 ` Thomas Petazzoni
2013-02-06 16:38 ` Linus Walleij
2013-02-07 0:54 ` Arnd Bergmann
2013-02-06 17:07 ` Linus Walleij
2013-02-07 1:20 ` Arnd Bergmann
2013-01-09 20:43 ` [PATCH 07/14] ARM: pci: Allow passing per-controller private data Thierry Reding
2013-01-09 20:43 ` [PATCH 08/14] ARM: tegra: Move tegra_pcie_xclk_clamp() to PMC Thierry Reding
2013-01-09 20:43 ` [PATCH 09/14] ARM: tegra: Move pmc.h to include/mach Thierry Reding
2013-01-11 0:15 ` Stephen Warren
2013-01-11 4:08 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 10/14] PCI: tegra: Move PCIe driver to drivers/pci/host Thierry Reding
2013-01-09 21:22 ` Arnd Bergmann
2013-01-09 21:58 ` Thierry Reding
2013-01-09 22:03 ` Arnd Bergmann
2013-01-10 23:54 ` Stephen Warren
2013-01-11 3:40 ` Thierry Reding
2013-01-11 15:36 ` Arnd Bergmann
2013-01-11 15:45 ` Thierry Reding
2013-01-12 12:36 ` Thierry Reding
2013-01-12 21:12 ` Arnd Bergmann
2013-01-13 9:58 ` Thierry Reding
2013-01-14 9:57 ` Andrew Murray [this message]
2013-01-15 12:08 ` Thierry Reding
2013-01-15 12:44 ` Arnd Bergmann
2013-01-15 15:40 ` Andrew Murray
2013-01-15 21:14 ` Thierry Reding
2013-01-16 14:00 ` Arnd Bergmann
2013-01-16 16:17 ` Andrew Murray
2013-01-16 18:31 ` Thierry Reding
2013-01-17 15:42 ` Andrew Murray
2013-01-17 16:05 ` Thierry Reding
2013-01-17 16:22 ` Andrew Murray
2013-01-17 20:30 ` Thierry Reding
2013-01-18 9:18 ` Andrew Murray
2013-01-22 19:29 ` Jason Gunthorpe
2013-01-29 13:31 ` Andrew Murray
2013-01-11 0:48 ` Stephen Warren
2013-01-11 3:52 ` Thierry Reding
2013-01-11 20:34 ` Stephen Warren
2013-01-18 9:56 ` Andrew Murray
2013-01-18 10:09 ` Thierry Reding
2013-02-13 23:11 ` Thomas Petazzoni
2013-01-09 20:43 ` [PATCH 11/14] ARM: tegra: tamonten: Add PCIe support Thierry Reding
2013-01-09 21:23 ` Arnd Bergmann
2013-01-10 20:21 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 12/14] ARM: tegra: tec: " Thierry Reding
2013-01-11 0:22 ` Stephen Warren
2013-01-11 4:34 ` Thierry Reding
2013-01-09 20:43 ` [PATCH 13/14] ARM: tegra: harmony: Initialize PCIe from DT Thierry Reding
2013-01-10 23:58 ` Stephen Warren
2013-01-09 20:43 ` [PATCH 14/14] ARM: tegra: trimslice: " Thierry Reding
2013-01-10 23:56 ` Stephen Warren
2013-01-11 18:48 ` Thierry Reding
2013-01-09 21:25 ` [PATCH 00/14] Rewrite Tegra PCIe driver Thomas Petazzoni
2013-01-10 6:55 ` Thierry Reding
2013-01-10 8:34 ` Thomas Petazzoni
2013-01-28 18:15 ` Bjorn Helgaas
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