From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Pankaj Bansal <pankaj.bansal@nxp.com>
Cc: Marc Zyngier <maz@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Makarand Pawagi <makarand.pawagi@nxp.com>,
Calvin Johnson <calvin.johnson@nxp.com>,
"stuyoder@gmail.com" <stuyoder@gmail.com>,
"nleeder@codeaurora.org" <nleeder@codeaurora.org>,
Ioana Ciornei <ioana.ciornei@nxp.com>,
Cristi Sovaiala <cristian.sovaiala@nxp.com>,
Hanjun Guo <guohanjun@huawei.com>, Will Deacon <will@kernel.org>,
"jon@solid-run.com" <jon@solid-run.com>,
Russell King <linux@armlinux.org.uk>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
Len Brown <lenb@kernel.org>, Jason Cooper <jason@lakedaemon.net>,
Andy Wang <Andy.Wang@arm.com>, Varun Sethi <V.Sethi@nxp.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Laurentiu Tudor <laurentiu.tudor@nxp.com>,
Paul Yang <Paul.Yang@arm.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [EXT] Re: [PATCH] bus: fsl-mc: Add ACPI support for fsl-mc
Date: Fri, 14 Feb 2020 17:49:49 +0000 [thread overview]
Message-ID: <20200214174949.GA30484@e121166-lin.cambridge.arm.com> (raw)
In-Reply-To: <VI1PR0401MB2496800C88A3A2CF912959E6F1150@VI1PR0401MB2496.eurprd04.prod.outlook.com>
On Fri, Feb 14, 2020 at 04:35:10PM +0000, Pankaj Bansal wrote:
[...]
> > -----Original Message-----
> > From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> > Sent: Friday, February 14, 2020 9:50 PM
> > To: Pankaj Bansal <pankaj.bansal@nxp.com>
> > Cc: Marc Zyngier <maz@kernel.org>; Ard Biesheuvel
> > <ard.biesheuvel@linaro.org>; Makarand Pawagi <makarand.pawagi@nxp.com>;
> > Calvin Johnson <calvin.johnson@nxp.com>; stuyoder@gmail.com;
> > nleeder@codeaurora.org; Ioana Ciornei <ioana.ciornei@nxp.com>; Cristi
> > Sovaiala <cristian.sovaiala@nxp.com>; Hanjun Guo <guohanjun@huawei.com>;
> > Will Deacon <will@kernel.org>; jon@solid-run.com; Russell King
> > <linux@armlinux.org.uk>; ACPI Devel Maling List <linux-acpi@vger.kernel.org>;
> > Len Brown <lenb@kernel.org>; Jason Cooper <jason@lakedaemon.net>; Andy
> > Wang <Andy.Wang@arm.com>; Varun Sethi <V.Sethi@nxp.com>; Thomas
> > Gleixner <tglx@linutronix.de>; linux-arm-kernel <linux-arm-
> > kernel@lists.infradead.org>; Laurentiu Tudor <laurentiu.tudor@nxp.com>; Paul
> > Yang <Paul.Yang@arm.com>; netdev@vger.kernel.org; Rafael J. Wysocki
> > <rjw@rjwysocki.net>; Linux Kernel Mailing List <linux-kernel@vger.kernel.org>;
> > Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>;
> > Sudeep Holla <sudeep.holla@arm.com>; Robin Murphy
> > <robin.murphy@arm.com>
> > Subject: Re: [EXT] Re: [PATCH] bus: fsl-mc: Add ACPI support for fsl-mc
Side note: would you mind removing the email headers (as above) in your
replies please ?
> > On Fri, Feb 14, 2020 at 03:58:14PM +0000, Pankaj Bansal wrote:
> >
> > [...]
> >
> > > > Why should the device know about its own ID? That's a bus/interconnect
> > thing.
> > > > And nothing should be passed *to* IORT. IORT is the source.
> > >
> > > IORT is translation between Input IDs <-> Output IDs. The Input ID is still
> > expected to be passed to parse IORT table.
> >
> > Named components use an array of single mappings (as in entries with single
> > mapping flag set) - Input ID is irrelevant.
> >
> > Not sure what your named component is though and what you want to do with
> > it, the fact that IORT allows mapping for named components do not necessarily
> > mean that it can describe what your system really is, on that you need to
> > elaborate for us to be able to help.
>
> Details about MC bus can be read from here:
> https://elixir.bootlin.com/linux/latest/source/Documentation/networking/device_drivers/freescale/dpaa2/overview.rst#L324
>
> As stated above, in Linux MC is a bus (just like PCI bus, AMBA bus etc)
> There can be multiple devices attached to this bus. Moreover, we can dynamically create/destroy these devices.
> Now, we want to represent this BUS (not individual devices connected to bus) in IORT table.
> The only possible way right now we see is that we describe it as Named components having a pool of ID mappings.
> As and when devices are created and attached to bus, we sift through this pool to correctly determine the output ID for the device.
> Now the input ID that we provide, can come from device itself.
> Then we can use the Platform MSI framework for MC bus devices.
So are you asking me if that's OK ? Or there is something you can't
describe with IORT ?
Side note: can you explain to me please how the MSI allocation flow
and kernel data structures/drivers are modeled in DT ? I had a quick
look at:
drivers/irqchip/irq-gic-v3-its-fsl-mc-msi.c
and to start with, does that code imply that we create a
DOMAIN_BUS_FSL_MC_MSI on ALL DT systems with an ITS device node ?
I *think* you have a specific API to allocate MSIs for MC devices:
fsl_mc_msi_domain_alloc_irqs()
which hook into the IRQ domain created in the file above that handles
the cascading to an ITS domain, correct ?
Thanks,
Lorenzo
next prev parent reply other threads:[~2020-02-14 17:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 8:08 [PATCH] bus: fsl-mc: Add ACPI support for fsl-mc Makarand Pawagi
2020-01-28 10:58 ` Marc Zyngier
2020-01-28 11:09 ` Lorenzo Pieralisi
2020-01-31 10:35 ` [EXT] " Makarand Pawagi
2020-01-31 11:06 ` Lorenzo Pieralisi
2020-01-31 11:06 ` Marc Zyngier
2020-01-31 12:01 ` Ard Biesheuvel
2020-01-31 12:28 ` Jon Nettleton
2020-01-31 12:48 ` Robin Murphy
2020-01-31 13:11 ` Jon Nettleton
2020-01-31 13:29 ` Ard Biesheuvel
2020-01-31 13:39 ` Robin Murphy
2020-01-31 14:29 ` Andrew Lunn
2020-01-31 14:47 ` Will Deacon
2020-01-31 15:09 ` Andrew Lunn
2020-01-31 15:14 ` Jon Nettleton
2020-01-31 15:41 ` Andrew Lunn
2020-01-31 15:39 ` Russell King - ARM Linux admin
2020-01-31 15:15 ` Russell King - ARM Linux admin
2020-01-31 15:40 ` Jakub Kicinski
2020-02-01 11:49 ` Russell King - ARM Linux admin
2020-02-01 17:36 ` Jakub Kicinski
2020-02-14 15:05 ` Pankaj Bansal
2020-02-14 15:54 ` Marc Zyngier
2020-02-14 15:58 ` Pankaj Bansal
2020-02-14 16:19 ` Lorenzo Pieralisi
2020-02-14 16:35 ` Pankaj Bansal
2020-02-14 17:49 ` Lorenzo Pieralisi [this message]
2020-02-17 12:35 ` Pankaj Bansal
2020-02-17 15:25 ` Lorenzo Pieralisi
2020-02-17 15:35 ` Marc Zyngier
2020-02-17 16:26 ` Lorenzo Pieralisi
2020-02-18 8:02 ` Pankaj Bansal (OSS)
2020-02-14 16:29 ` Robin Murphy
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