> -----Original Message-----
> From: Xu, Yilun <yilun.xu@xxxxxxxxx>
> Sent: Monday, April 25, 2022 4:20 PM
> To: Zhang, Tianfei <tianfei.zhang@xxxxxxxxx>
> Cc: Wu, Hao <hao.wu@xxxxxxxxx>; trix@xxxxxxxxxx; mdf@xxxxxxxxxx; linux-
> fpga@xxxxxxxxxxxxxxx; Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH v2] fpga: dfl: Allow Port to be linked to FME's DFL
>
> On Tue, Apr 19, 2022 at 03:52:24AM -0400, Tianfei Zhang wrote:
> > From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> >
> > Currently we use PORTn_OFFSET to locate PORT DFLs, and PORT DFLs are
> > not connected FME DFL. But for some cases (e.g. Intel Open FPGA Stack
> > device), PORT DFLs are connected to FME DFL directly, so we don't need
> > to search PORT DFLs via PORTn_OFFSET again. If BAR value of
> > PORTn_OFFSET is 0x7
> > (FME_PORT_OFST_BAR_SKIP) then driver will skip searching the DFL for
> > that port. If BAR value is invalid, return -EINVAL.
> >
> > Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> > Signed-off-by: Tianfei Zhang <tianfei.zhang@xxxxxxxxx>
> > ---
> > v2: return -EINVAL if bar number invalid.
> > ---
> > drivers/fpga/dfl-pci.c | 11 +++++++++++
> > drivers/fpga/dfl.h | 1 +
> > 2 files changed, 12 insertions(+)
> >
> > diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c index
> > 86ed9e4223d3..5bd6ef231ccc 100644
> > --- a/drivers/fpga/dfl-pci.c
> > +++ b/drivers/fpga/dfl-pci.c
> > @@ -263,6 +263,17 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
> > */
> > bar = FIELD_GET(FME_PORT_OFST_BAR_ID, v);
> > offset = FIELD_GET(FME_PORT_OFST_DFH_OFST, v);
> > + if (bar == FME_PORT_OFST_BAR_SKIP) {
> > + dev_dbg(&pcidev->dev, "skipping search DFL
> for port %d on BAR %d\n",
> > + i, bar);
>
> I suggest we remove the dev_dbg, it's a normal case in DFL walking.
I agree.
>
> > + continue;
> > + } else if (bar >= PCI_STD_NUM_BARS) {
> > + dev_err(&pcidev->dev, "bad BAR %d for port
> %d\n",
> > + bar, i);
> > + ret = -EINVAL;
> > + break;
>
> The code is workable, but I suggest we use goto instead of break for error out.
Ok, use goto is fine, I will change for next patch.
>
> Thanks,
> Yilun
>
> > + }
> > +
> > start = pci_resource_start(pcidev, bar) + offset;
> > len = pci_resource_len(pcidev, bar) - offset;
> >
> > diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h index
> > 53572c7aced0..e0f0abfbeb8c 100644
> > --- a/drivers/fpga/dfl.h
> > +++ b/drivers/fpga/dfl.h
> > @@ -91,6 +91,7 @@
> > #define FME_HDR_PORT_OFST(n) (0x38 + ((n) * 0x8))
> > #define FME_HDR_BITSTREAM_ID 0x60
> > #define FME_HDR_BITSTREAM_MD 0x68
> > +#define FME_PORT_OFST_BAR_SKIP 7
> >
> > /* FME Fab Capability Register Bitfield */
> > #define FME_CAP_FABRIC_VERID GENMASK_ULL(7, 0) /* Fabric
> version ID */
> > --
> > 2.26.2
