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

[Marc Zyngier]

On 2019-12-03 01:42, Xiaowei Bao wrote:
> > -----Original Message-----
> > From: Marc Zyngier <maz@xxxxxxxxxxxxxxx>
> > Sent: 2019å12æ2æ 20:48
> > To: Xiaowei Bao <xiaowei.bao@xxxxxxx>
> > Cc: robh+dt@xxxxxxxxxx; frowand.list@xxxxxxxxx; M.h. Lian
> > <minghuan.lian@xxxxxxx>; Mingkai Hu <mingkai.hu@xxxxxxx>; Roy Zang
> > <roy.zang@xxxxxxx>; lorenzo.pieralisi@xxxxxxx; 
> > andrew.murray@xxxxxxx;
> > bhelgaas@xxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> > linux-kernel@xxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx;
> > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Z.q. Hou 
> > <zhiqiang.hou@xxxxxxx>
> > 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@xxxxxxx>
> > > ---
> > >  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.

Why can't firmware expose an msi-map/msi-map-mask that has a large
enough range to ensure mapping of VFs? What are the limitations of
the LUT that would prevent this from being configured before the
kernel boots?

Thanks,

        M.
--
Jazz is not dead. It just smells funny...