> > -----Original Message----- > > From: Xu, Yilun <yilun.xu@xxxxxxxxx> > > Sent: Sunday, April 17, 2022 12:18 AM > > 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 v1] fpga: dfl: Allow Port to be linked to FME's DFL > > > > On Wed, Apr 13, 2022 at 05:15:19AM -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. > > > > > > Link: > > > https://lore.kernel.org/linux-fpga/20220316070814.1916017-2-tianfei.zh > > > ang@xxxxxxxxx/ > > > Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx> > > > Signed-off-by: Tianfei Zhang <tianfei.zhang@xxxxxxxxx> > > > --- > > > drivers/fpga/dfl-pci.c | 7 +++++++ > > > drivers/fpga/dfl.h | 1 + > > > 2 files changed, 8 insertions(+) > > > > > > diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c index > > > 717ac9715970..6347f31058f0 100644 > > > --- a/drivers/fpga/dfl-pci.c > > > +++ b/drivers/fpga/dfl-pci.c > > > @@ -259,6 +259,13 @@ 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 >= PCI_STD_NUM_BARS || > > > + bar == FME_PORT_OFST_BAR_SKIP) { > > > > Seems the second judgement will never be triggered? > > The value is overlap, but there are different meaning, " bar >= > PCI_STD_NUM_BARS" means that the bar was invalid during the PCIe spec, > "bar == FME_PORT_OFST_BAR_SKIP" means that the HW tell us that the SW > should skip searching the DFL for the port. So first case is a HW bug we should return error, and second case is a valid case to skip searching DFL, right? > > > > > Thanks > > Yilun > > > > > + dev_dbg(&pcidev->dev, "skipping search DFL > > for port %d on BAR %d\n", > > > + i, bar); > > > + continue; > > > + } > > > + > > > 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
