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Message-ID: <DB7PR04MB4986A8A3427DBA096628D6FBEBDB0@DB7PR04MB4986.eurprd04.prod.outlook.com>
Date: Wed, 15 Apr 2020 05:42:03 +0000
From: Makarand Pawagi <makarand.pawagi@....com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Laurentiu Tudor <laurentiu.tudor@....com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
"robin.murphy@....com" <robin.murphy@....com>,
"ard.biesheuvel@...aro.org" <ard.biesheuvel@...aro.org>,
Ioana Ciornei <ioana.ciornei@....com>,
"Diana Madalina Craciun (OSS)" <diana.craciun@....nxp.com>,
"maz@...nel.org" <maz@...nel.org>,
"jon@...id-run.com" <jon@...id-run.com>,
Pankaj Bansal <pankaj.bansal@....com>,
Calvin Johnson <calvin.johnson@....com>,
Varun Sethi <V.Sethi@....com>,
Cristi Sovaiala <cristian.sovaiala@....com>,
"Stuart.Yoder@....com" <Stuart.Yoder@....com>,
"jeremy.linton@....com" <jeremy.linton@....com>,
"joro@...tes.org" <joro@...tes.org>,
"tglx@...utronix.de" <tglx@...utronix.de>,
"jason@...edaemon.net" <jason@...edaemon.net>
Subject: RE: [EXT] Re: [RFC PATCH 1/4] bus: fsl-mc: add custom .dma_configure
implementation
> -----Original Message-----
> From: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
> Sent: Tuesday, April 14, 2020 8:02 PM
> To: Laurentiu Tudor <laurentiu.tudor@....com>
> Cc: linux-kernel@...r.kernel.org; iommu@...ts.linux-foundation.org; linux-arm-
> kernel@...ts.infradead.org; linux-acpi@...r.kernel.org;
> robin.murphy@....com; ard.biesheuvel@...aro.org; Ioana Ciornei
> <ioana.ciornei@....com>; Diana Madalina Craciun (OSS)
> <diana.craciun@....nxp.com>; maz@...nel.org; jon@...id-run.com; Pankaj
> Bansal <pankaj.bansal@....com>; Makarand Pawagi
> <makarand.pawagi@....com>; Calvin Johnson <calvin.johnson@....com>;
> Varun Sethi <V.Sethi@....com>; Cristi Sovaiala <cristian.sovaiala@....com>;
> Stuart.Yoder@....com; jeremy.linton@....com; joro@...tes.org;
> tglx@...utronix.de; jason@...edaemon.net
> Subject: [EXT] Re: [RFC PATCH 1/4] bus: fsl-mc: add custom .dma_configure
> implementation
>
> Caution: EXT Email
>
> On Wed, Mar 25, 2020 at 06:48:55PM +0200, Laurentiu Tudor wrote:
> > Hi Lorenzo,
> >
> > On 3/25/2020 2:51 PM, Lorenzo Pieralisi wrote:
> > > On Thu, Feb 27, 2020 at 12:05:39PM +0200, laurentiu.tudor@....com wrote:
> > >> From: Laurentiu Tudor <laurentiu.tudor@....com>
> > >>
> > >> The devices on this bus are not discovered by way of device tree
> > >> but by queries to the firmware. It makes little sense to trick the
> > >> generic of layer into thinking that these devices are of related so
> > >> that we can get our dma configuration. Instead of doing that, add
> > >> our custom dma configuration implementation.
> > >>
> > >> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@....com>
> > >> ---
> > >> drivers/bus/fsl-mc/fsl-mc-bus.c | 31
> > >> ++++++++++++++++++++++++++++++-
> > >> 1 file changed, 30 insertions(+), 1 deletion(-)
> > >>
> > >> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c
> > >> b/drivers/bus/fsl-mc/fsl-mc-bus.c index 36eb25f82c8e..eafaa0e0b906
> > >> 100644
> > >> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c
> > >> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
> > >> @@ -132,11 +132,40 @@ static int fsl_mc_bus_uevent(struct device
> > >> *dev, struct kobj_uevent_env *env) static int
> > >> fsl_mc_dma_configure(struct device *dev) {
> > >> struct device *dma_dev = dev;
> > >> + struct iommu_fwspec *fwspec;
> > >> + const struct iommu_ops *iommu_ops; struct fsl_mc_device *mc_dev
> > >> + = to_fsl_mc_device(dev); int ret;
> > >> + u32 icid;
> > >>
> > >> while (dev_is_fsl_mc(dma_dev))
> > >> dma_dev = dma_dev->parent;
> > >>
> > >> - return of_dma_configure(dev, dma_dev->of_node, 0);
> > >> + fwspec = dev_iommu_fwspec_get(dma_dev); if (!fwspec)
> > >> + return -ENODEV;
> > >> + iommu_ops = iommu_ops_from_fwnode(fwspec->iommu_fwnode);
> > >> + if (!iommu_ops)
> > >> + return -ENODEV;
> > >> +
> > >> + ret = iommu_fwspec_init(dev, fwspec->iommu_fwnode, iommu_ops);
> > >> + if (ret)
> > >> + return ret;
> > >> +
> > >> + icid = mc_dev->icid;
> > >> + ret = iommu_fwspec_add_ids(dev, &icid, 1);
> > >
> > > I see. So with this patch we would use the MC named component only
> > > to retrieve the iommu_ops
> >
> > Right. I'd also add that the implementation tries to follow the
> > existing standard .dma_configure implementations, e.g.
> > of_dma_configure + of_iommu_configure. I'd also note that similarly to
> > the ACPI case, this MC FW device is probed as a platform device in the
> > DT scenario, binding here [1].
> > A similar approach is used for the retrieval of the msi irq domain,
> > see following patch.
> >
> > > - the streamid are injected directly here bypassing OF/IORT bindings
> translations altogether.
> >
> > Actually I've submitted a v2 [2] that calls into .of_xlate() to allow
> > the smmu driver to do some processing on the raw streamid coming from
> > the firmware. I have not yet tested this with ACPI but expect it to
> > work, however, it's debatable how valid is this approach in the
> > context of ACPI.
>
> Actually, what I think you need is of_map_rid() (and an IORT equivalent, that I
> am going to write - generalizing iort_msi_map_rid()).
>
That would help.
> Would that be enough to enable IORT "normal" mappings in the MC bus named
> components ?
>
But still the question remain unanswered that how we are going to represent MC? As Platform device with single ID mapping flag?
> Thanks,
> Lorenzo
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