Re: [PATCH V12 01/12] PCI: Add #defines for some of PCIe spec r4.0 features

[Vidya Sagar]

On 7/9/2019 7:44 PM, Bjorn Helgaas wrote:
> On Mon, Jul 01, 2019 at 06:09:59PM +0530, Vidya Sagar wrote:
> > Add #defines only for the Data Link Feature and Physical Layer 16.0 GT/s
> > features.
> >
> > Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
> > Reviewed-by: Thierry Reding <treding@xxxxxxxxxx>
>
> Please include spec references in the commit log, e.g., PCIe r5.0, sec
> 7.7.4, for Data Link Feature and sec 7.7.5 for Physical Layer 16 GT/s.
Done.

> >   include/uapi/linux/pci_regs.h | 22 +++++++++++++++++++++-
> >   1 file changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> > index f28e562d7ca8..1c79f6a097d2 100644
> > --- a/include/uapi/linux/pci_regs.h
> > +++ b/include/uapi/linux/pci_regs.h
> > @@ -713,7 +713,9 @@
> >   #define PCI_EXT_CAP_ID_DPC	0x1D	/* Downstream Port Containment */
> >   #define PCI_EXT_CAP_ID_L1SS	0x1E	/* L1 PM Substates */
> >   #define PCI_EXT_CAP_ID_PTM	0x1F	/* Precision Time Measurement */
> > -#define PCI_EXT_CAP_ID_MAX	PCI_EXT_CAP_ID_PTM
> > +#define PCI_EXT_CAP_ID_DLF	0x25	/* Data Link Feature */
> > +#define PCI_EXT_CAP_ID_PL	0x26	/* Physical Layer 16.0 GT/s */
>
> Maybe PCI_EXT_CAP_ID_PL_16GT so there's a little more hint of what
> this is for?
Ok. I'll add 16GT.

> > +#define PCI_EXT_CAP_ID_MAX	PCI_EXT_CAP_ID_PL
> >   
> >   #define PCI_EXT_CAP_DSN_SIZEOF	12
> >   #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
> > @@ -1053,4 +1055,22 @@
> >   #define  PCI_L1SS_CTL1_LTR_L12_TH_SCALE	0xe0000000  /* LTR_L1.2_THRESHOLD_Scale */
> >   #define PCI_L1SS_CTL2		0x0c	/* Control 2 Register */
> >   
> > +/* Data Link Feature */
> > +#define PCI_DLF_CAP		0x04	/* Capabilities Register */
> > +#define  PCI_DLF_LOCAL_DLF_SUP_MASK	0x007fffff  /* Local Data Link Feature Supported */
> > +#define  PCI_DLF_EXCHANGE_ENABLE	0x80000000  /* Data Link Feature Exchange Enable */
> > +#define PCI_DLF_STS		0x08	/* Status Register */
> > +#define  PCI_DLF_REMOTE_DLF_SUP_MASK	0x007fffff  /* Remote Data Link Feature Supported */
> > +#define  PCI_DLF_REMOTE_DLF_SUP_VALID	0x80000000  /* Remote Data Link Feature Support Valid */
>
> I'm a little bit ambivalent about adding #defines that aren't used.  I
> personally would probably just add the things we use, so the header
> file gives a clue about what's currently implemented.  But I guess
> either way is fine.
Fine. I'll remove all unused defines in the next patch.

> > +/* Physical Layer 16.0 GT/s */
> > +#define PCI_PL_16GT_CAP		0x04	/* Capabilities Register */
> > +#define PCI_PL_16GT_CTRL	0x08	/* Control Register */
> > +#define PCI_PL_16GT_STS		0x0c	/* Status Register */
> > +#define PCI_PL_16GT_LDPM_STS	0x10	/* Local Data Parity Mismatch Status Register */
> > +#define PCI_PL_16GT_FRDPM_STS	0x14	/* First Retimer Data Parity Mismatch Status Register */
> > +#define PCI_PL_16GT_SRDPM_STS	0x18	/* Second Retimer Data Parity Mismatch Status Register */
> > +#define PCI_PL_16GT_RSVD	0x1C	/* Reserved */
>
> Use lower-case hex consistently here.  There's no global consistency
> in this file, but we can at least be consistent in each section.  But
> I'm even more hesitant about included unused #defines for "reserved"
> fields, so if you drop this it would take care of both :)
Done.

> > +#define PCI_PL_16GT_LE_CTRL	0x20	/* Lane Equalization Control Register */
>
> This is the only register you actually use.  You defined a local
> PL16G_CAP_OFF_DSP_16G_TX_PRESET_MASK for this register.  Shouldn't
> that be defined here instead of in
> drivers/pci/controller/dwc/pcie-tegra194.c?
I'll take care of it in the next patch.

> >   #endif /* LINUX_PCI_REGS_H */
> > --
> > 2.17.1