Re: [PATCH 07/11] PCI: Add PCIe Device 3 Extended Capability enumeration

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Ilpo Järvinen wrote:
> On Thu, 5 Dec 2024, Dan Williams wrote:
> 
> > PCIe 6.2 Section 7.7.9 Device 3 Extended Capability Structure,
> > enumerates new link capabilities and status added for Gen 6 devices. One
> > of the link details enumerated in that register block is the "Segment
> > Captured" status in the Device Status 3 register. That status is
> > relevant for enabling IDE (Integrity & Data Encryption) whereby
> > Selective IDE streams can be limited to a given requester id range
> > within a given segment.
> > 
> > If a device has captured its Segment value then it knows that PCIe Flit
> > Mode is enabled via all links in the path that a configuration write
> > traversed. IDE establishment requires that "Segment Base" in
> > IDE RID Association Register 2 (PCIe 6.2 Section 7.9.26.5.4.2) be
> > programmed if the RID association mechanism is in effect.
> > 
> > When / if IDE + Flit Mode capable devices arrive, the PCI core needs to
> > setup the segment base when using the RID association facility, but no
> > known deployments today depend on this.
> > 
> > Cc: Lukas Wunner <lukas@xxxxxxxxx>
> > Cc: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> > Cc: Samuel Ortiz <sameo@xxxxxxxxxxxx>
> > Cc: Alexey Kardashevskiy <aik@xxxxxxx>
> > Cc: Xu Yilun <yilun.xu@xxxxxxxxxxxxxxx>
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
[..]
> > @@ -1210,6 +1211,12 @@
> >  #define PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL		0x00ff0000
> >  #define PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX	0xff000000
> >  
> > +/* Device 3 Extended Capability */
> > +#define PCI_DEV3_CAP		0x4	/* Device 3 Capabilities Register */
> > +#define PCI_DEV3_CTL		0x8	/* Device 3 Control Register */
> 
> Should save/restore too be added for DEV3_CTL?

Good point, yes it should.




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