RE: [PATCH] PCI: layerscape: Add the SRIOV support in host side

[Laurentiu Tudor <laurentiu.tudor@nxp.com>]

Hi Xiaowei,

> -----Original Message-----
> From: linux-arm-kernel <linux-arm-kernel-bounces@lists.infradead.org> On
> Behalf Of Xiaowei Bao
> 
> > -----Original Message-----
> > From: Marc Zyngier <maz@misterjones.org>
> > Sent: 2019年12月2日 20:48
> > To: Xiaowei Bao <xiaowei.bao@nxp.com>
> > Cc: robh+dt@kernel.org; frowand.list@gmail.com; M.h. Lian
> > <minghuan.lian@nxp.com>; Mingkai Hu <mingkai.hu@nxp.com>; Roy Zang
> > <roy.zang@nxp.com>; lorenzo.pieralisi@arm.com; andrew.murray@arm.com;
> > bhelgaas@google.com; devicetree@vger.kernel.org;
> > linux-kernel@vger.kernel.org; linux-pci@vger.kernel.org;
> > linux-arm-kernel@lists.infradead.org; Z.q. Hou <zhiqiang.hou@nxp.com>
> > Subject: Re: [PATCH] PCI: layerscape: Add the SRIOV support in host side
> >
> > On 2019-12-02 10:45, Xiaowei Bao wrote:
> > > GIC get the map relations of devid and stream id from the msi-map
> > > property of DTS, our platform add this property in u-boot base on the
> > > PCIe device in the bus, but if enable the vf device in kernel, the vf
> > > device msi-map will not set, so the vf device can't work, this patch
> > > purpose is that manage the stream id and device id map relations
> > > dynamically in kernel, and make the new PCIe device work in kernel.
> > >
> > > Signed-off-by: Xiaowei Bao <xiaowei.bao@nxp.com>
> > > ---
> > >  drivers/of/irq.c                            |  9 +++
> > >  drivers/pci/controller/dwc/pci-layerscape.c | 94
> > > +++++++++++++++++++++++++++++
> > >  drivers/pci/probe.c                         |  6 ++
> > >  drivers/pci/remove.c                        |  6 ++
> > >  4 files changed, 115 insertions(+)
> > >
> > > diff --git a/drivers/of/irq.c b/drivers/of/irq.c index
> > > a296eaf..791e609 100644
> > > --- a/drivers/of/irq.c
> > > +++ b/drivers/of/irq.c
> > > @@ -576,6 +576,11 @@ void __init of_irq_init(const struct of_device_id
> > > *matches)
> > >  	}
> > >  }
> > >
> > > +u32 __weak ls_pcie_streamid_fix(struct device *dev, u32 rid) {
> > > +	return rid;
> > > +}
> > > +
> > >  static u32 __of_msi_map_rid(struct device *dev, struct device_node
> > > **np,
> > >  			    u32 rid_in)
> > >  {
> > > @@ -590,6 +595,10 @@ static u32 __of_msi_map_rid(struct device *dev,
> > > struct device_node **np,
> > >  		if (!of_map_rid(parent_dev->of_node, rid_in, "msi-map",
> > >  				"msi-map-mask", np, &rid_out))
> > >  			break;
> > > +
> > > +	if (rid_out == rid_in)
> > > +		rid_out = ls_pcie_streamid_fix(parent_dev, rid_in);
> >
> > Over my dead body. Get your firmware to properly program the LUT so that
> it
> > presents the ITS with a reasonable topology. There is absolutely no way
> this
> > kind of change makes it into the kernel.
> 
> Sorry for this, I know it is not reasonable, but I have no other way, as I
> know, ARM
> get the mapping of stream ID to request ID from the msi-map property of
> DTS, if
> add a new device which need the stream ID and try to get it from the msi-
> map of DTS,
> it will failed and not work, yes? So could you give me a better advice to
> fix this issue,
> I would really appreciate any comments or suggestions, thanks a lot.
> 

I agree with the community that this should be tackled in firmware. I actually submitted (by mistake, but let's disregard that :-)) a simple proposal in u-boot [1] that should take care of it. We can discuss further on it, if you wish.

[1] https://patchwork.ozlabs.org/patch/1033466/

---
Best Regards, Laurentiu
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