From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC v1 08/16] arm: mvebu: the core PCIe driver
Date: Thu, 13 Dec 2012 21:46:05 +0000 [thread overview]
Message-ID: <201212132146.05829.arnd@arndb.de> (raw)
In-Reply-To: <20121213201206.69452b8f@skate>
On Thursday 13 December 2012, Thomas Petazzoni wrote:
> Dear Jason Gunthorpe,
>
> On Thu, 13 Dec 2012 10:54:42 -0700, Jason Gunthorpe wrote:
> > On Thu, Dec 13, 2012 at 12:19:39PM +0000, Arnd Bergmann wrote:
> >
> > > Do those ten ports have a shared I/O space window, or does each one
> > > have its own 64K?
> >
> > The smallest mbus routing window size is 64k, and you need to use a
> > mbus routing window per PEX to decode into IO.
>
> Correct.
>
> > Thomas: Note this complicates my earlier suggestion of just using
> > config transactions because this is horribly non-conformant, PCIe
> > requires a much finer granularity for the root port bridge, it would
> > need some kind of specialness to make the standard Linux resource
> > allocator work properly.... :|
>
> Hum, not sure to follow you here. What sort of finer granularity does
> PCIe requires?
It's common for multiple buses to share a single I/O address space,
and just allocate port numbers for each BAR from a global 64KB
window, because x86 only has a single 64KB I/O space in hardware.
Maybe it works correctly if you set up all ten I/O windows to point
to the same addresses? I don't have the documentation, so it might
say that this is unsupported, but otherwise it may be worth trying.
> > By far the easiest thing is to keep them as separate PCI busses and
> > require DT to manage each one individually, address ranges and
> > all. :(
>
> Does that mean that your earlier suggestion of emulating a PCI-to-PCI
> bridge in software is no longer your preferred suggestion?
If the child buses of that virtual bridge can't use the same I/O
space window, that would require significant changes to the Linux
PCI implementation, which does not sound right.
One possibility would be to declare I/O space accesses invalid on this
driver, but that would break support for a number of (older) devices.
Arnd
next prev parent reply other threads:[~2012-12-13 21:46 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-07 22:04 [RFC v1] PCIe support for the Armada 370 and Armada XP SoCs Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 01/16] lib: devres: don't enclose pcim_*() functions in CONFIG_HAS_IOPORT Thomas Petazzoni
2012-12-11 10:43 ` Arnd Bergmann
2012-12-11 16:03 ` Thomas Petazzoni
2012-12-11 16:15 ` Arnd Bergmann
2012-12-11 16:23 ` Russell King - ARM Linux
2012-12-11 16:38 ` Thomas Petazzoni
2012-12-11 16:50 ` Russell King - ARM Linux
2012-12-11 17:29 ` Alan Cox
2012-12-11 22:20 ` Arnd Bergmann
2012-12-11 22:34 ` Arnd Bergmann
2012-12-11 16:30 ` Thomas Petazzoni
2012-12-11 16:46 ` Russell King - ARM Linux
2012-12-11 17:32 ` Alan Cox
2012-12-11 22:28 ` Arnd Bergmann
2012-12-11 16:55 ` Russell King - ARM Linux
2012-12-11 16:26 ` Russell King - ARM Linux
2012-12-11 17:16 ` Alan Cox
2012-12-11 17:34 ` Russell King - ARM Linux
2012-12-11 17:45 ` Alan Cox
2012-12-11 17:51 ` Russell King - ARM Linux
2012-12-07 22:04 ` [RFC v1 02/16] clk: mvebu: create parent-child relation for PCIe clocks on Armada 370 Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 03/16] arm: plat-orion: introduce WIN_CTRL_ENABLE in address mapping code Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 04/16] arm: plat-orion: refactor the orion_disable_wins() function Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 05/16] arm: plat-orion: introduce orion_{alloc, free}_cpu_win() functions Thomas Petazzoni
2012-12-08 11:53 ` [RFC v1 05/16] arm: plat-orion: introduce orion_{alloc,free}_cpu_win() functions Andrew Lunn
2012-12-08 12:15 ` Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 06/16] arm: mvebu: add functions to alloc/free PCIe decoding windows Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 07/16] arm: plat-orion: make common PCIe code usable on mvebu Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 08/16] arm: mvebu: the core PCIe driver Thomas Petazzoni
2012-12-10 8:28 ` Andrew Lunn
2012-12-10 8:45 ` Thomas Petazzoni
2012-12-10 19:08 ` Jason Gunthorpe
2012-12-11 10:56 ` Arnd Bergmann
2012-12-12 15:58 ` Thomas Petazzoni
2012-12-12 21:51 ` Jason Gunthorpe
2012-12-13 14:58 ` Arnd Bergmann
2012-12-13 17:40 ` Jason Gunthorpe
2012-12-13 19:09 ` Thomas Petazzoni
2012-12-14 19:34 ` Rob Herring
2012-12-13 12:19 ` Arnd Bergmann
2012-12-13 17:54 ` Jason Gunthorpe
2012-12-13 19:12 ` Thomas Petazzoni
2012-12-13 21:46 ` Arnd Bergmann [this message]
2012-12-13 22:27 ` Jason Gunthorpe
2012-12-07 22:04 ` [RFC v1 09/16] arm: mvebu: PCIe support is now available on mvebu Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 10/16] arm: mvebu: add PCIe Device Tree informations for Armada 370 Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 11/16] arm: mvebu: add PCIe Device Tree informations for Armada XP Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 12/16] arm: mvebu: PCIe Device Tree informations for OpenBlocks AX3-4 Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 13/16] arm: mvebu: PCIe Device Tree informations for Armada XP DB Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 14/16] arm: mvebu: PCIe Device Tree informations for Armada 370 Mirabox Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 15/16] arm: mvebu: PCIe Device Tree informations for Armada 370 DB Thomas Petazzoni
2012-12-07 22:04 ` [RFC v1 16/16] arm: mvebu: update defconfig with PCI and USB support Thomas Petazzoni
2012-12-07 23:33 ` [RFC v1] PCIe support for the Armada 370 and Armada XP SoCs Jason Gunthorpe
2012-12-10 17:52 ` Stephen Warren
2012-12-10 18:05 ` Thomas Petazzoni
2012-12-10 18:16 ` Stephen Warren
2012-12-10 18:59 ` Thomas Petazzoni
2012-12-10 19:07 ` Jason Gunthorpe
2012-12-10 20:08 ` Stephen Warren
2012-12-10 18:44 ` Jason Gunthorpe
2012-12-10 19:03 ` Thomas Petazzoni
2012-12-10 19:18 ` Jason Gunthorpe
2012-12-12 16:04 ` Thomas Petazzoni
2012-12-12 20:09 ` Jason Gunthorpe
2012-12-16 13:02 ` Thierry Reding
2012-12-11 7:52 ` Thierry Reding
2012-12-11 21:21 ` Stephen Warren
2012-12-12 20:34 ` Thierry Reding
2012-12-12 22:30 ` Stephen Warren
2012-12-13 7:03 ` Thierry Reding
2012-12-13 8:04 ` Jason Gunthorpe
2012-12-13 8:23 ` Thierry Reding
2012-12-13 18:12 ` Stephen Warren
2012-12-13 20:42 ` Thierry Reding
2012-12-13 20:47 ` Jason Gunthorpe
2012-12-13 21:16 ` Thierry Reding
2012-12-14 10:05 ` Thierry Reding
2012-12-14 15:10 ` Thierry Reding
2012-12-14 17:27 ` Jason Gunthorpe
2012-12-16 12:33 ` Thierry Reding
2012-12-17 18:29 ` Jason Gunthorpe
2012-12-17 19:41 ` Thierry Reding
2012-12-18 2:10 ` Stephen Warren
2012-12-18 2:51 ` Jason Gunthorpe
2012-12-18 17:03 ` Stephen Warren
2012-12-20 15:32 ` Thierry Reding
2012-12-21 13:38 ` Jay Agarwal
2012-12-21 14:03 ` Thierry Reding
2012-12-22 14:50 ` Thomas Petazzoni
2012-12-28 21:06 ` Thierry Reding
2012-12-28 21:16 ` Thomas Petazzoni
2012-12-28 23:49 ` Stephen Warren
2012-12-29 8:09 ` Thomas Petazzoni
2012-12-31 16:40 ` Stephen Warren
2012-12-29 9:33 ` Thierry Reding
2012-12-31 16:44 ` Stephen Warren
2013-01-02 20:09 ` Jason Gunthorpe
2013-01-03 14:20 ` Thierry Reding
2012-12-28 23:51 ` Stephen Warren
2012-12-18 7:32 ` Thierry Reding
2013-01-03 14:39 ` Thierry Reding
2013-01-03 15:00 ` Bjorn Helgaas
2013-01-03 15:11 ` Thierry Reding
2013-01-03 15:09 ` Thomas Petazzoni
2013-01-03 15:56 ` Arnd Bergmann
2013-01-03 16:01 ` Thierry Reding
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