Re: [RFC} arm architecture board/feature deprecation timeline
- To: Arnd Bergmann <arnd@arndb.de>
- Cc: "Jeremy J. Peper" <jeremy@jeremypeper.com>, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Russell King <linux@armlinux.org.uk>, Linus Walleij <linus.walleij@linaro.org>, Richard Earnshaw <richard.earnshaw@arm.com>, Richard Sandiford <richard.sandiford@arm.com>, Ramana Radhakrishnan <ramanara@nvidia.com>, Nicolas Pitre <nico@fluxnic.net>, Krzysztof Kozlowski <krzk@kernel.org>, Mark Brown <broonie@kernel.org>, Kristoffer Ericson <kristoffer.ericson@gmail.com>, Robert Jarzmik <robert.jarzmik@free.fr>, Aaro Koskinen <aaro.koskinen@iki.fi>, Janusz Krzysztofik <jmkrzyszt@gmail.com>, Tony Lindgren <tony@atomide.com>, Linux-OMAP <linux-omap@vger.kernel.org>, Nikita Shubin <nikita.shubin@maquefel.me>, linux-samsung-soc@vger.kernel.org, Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>, Gregory Clement <gregory.clement@bootlin.com>, debian-arm@lists.debian.org, Dmitry Torokhov <dmitry.torokhov@gmail.com>, Alexandre Torgue <alexandre.torgue@foss.st.com>
- Subject: Re: [RFC} arm architecture board/feature deprecation timeline
- From: Andrew Lunn <andrew@lunn.ch>
- Date: Mon, 19 Aug 2024 16:23:16 +0200
- Message-id: <[🔎] a6316f7c-4064-4145-aa6a-d34197a3981a@lunn.ch>
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On Mon, Aug 19, 2024 at 04:12:10PM +0200, Arnd Bergmann wrote:
> Two small additions:
>
> On Mon, Aug 19, 2024, at 11:17, Arnd Bergmann wrote:
> > On Thu, Aug 15, 2024, at 21:53, jeremy@jeremypeper.com wrote:
> > I expect that the terastation pro2 is going to be fairly easy to
> > convert to DT as there is already support for similar Orion5x
> > machines. In this case I would just remove all the Orion5x board
> > files and you can add a dts file later on. The bit I'm unsure
> > about here is legacy PCI support. I see that the board file enables
> > both PCI and PCIe, but I don't know if both are actually used,
> > or if everything is on PCIe.
> >
> > I have some old patches for separating orion legacy PCI from
> > PCIe support, as only the latter has a modern driver (shared
> > with kirkwood and armadaxp). If you can confirm that the machine
> > actually uses PCI, I can dig those out from my backups.
>
> I did find this myself later, the machine does use an on-board
> PCI connected SATA controller, which is obviously required to
> make the machine useful.
>
> Doing a PCI host bridge driver with DT support correctly is
> a lot of work, especially if there is only a single machine
> using it. Since this uses the same drivers/ata/sata-mv.c
> driver as the other orion/kirkwood machines, I wonder if we
> can just pretend that this is a platform device and skip
> all of the PCI probing. I think this only needs a few
> small changes to the sata-mv.c driver, but it does require
> that the PCI bus is left in a known state by the boot loader.
It is a long time since i looked at Orion, so i could be wrong....
As far as i remember, it has a PCI controller and a PCIe
controller. They are slightly different. The PCIe part is i think
simpler to support, it follows the standards better. I _think_ the PCI
controller uses a GPIO for interrupt support, which causes a mess.
If only PCIe is needed, it should not be too hard to make work. I
would try to avoid the PCI controller is possible.
Andrew
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