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SubjectRE: [PATCH] fpga: dfl: pci: gracefully handle misconfigured port entries
Date
> On Wed, 21 Apr 2021, Wu, Hao wrote:
>
> >> Subject: [PATCH] fpga: dfl: pci: gracefully handle misconfigured port entries
> >>
> >> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> >>
> >> Gracefully ignore misconfigured port entries encountered in
> >> incorrect FPGA images.
> >>
> >> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> >> ---
> >> drivers/fpga/dfl-pci.c | 16 +++++++++++++++-
> >> 1 file changed, 15 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> >> index b44523e..660d3b6 100644
> >> --- a/drivers/fpga/dfl-pci.c
> >> +++ b/drivers/fpga/dfl-pci.c
> >> @@ -212,6 +212,7 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
> >> int port_num, bar, i, ret = 0;
> >> resource_size_t start, len;
> >> void __iomem *base;
> >> + int bars = 0;
> >> u32 offset;
> >> u64 v;
> >>
> >> @@ -228,6 +229,7 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
> >> if (dfl_feature_is_fme(base)) {
> >> start = pci_resource_start(pcidev, 0);
> >> len = pci_resource_len(pcidev, 0);
> >> + bars |= BIT(0);
> >>
> >> dfl_fpga_enum_info_add_dfl(info, start, len);
> >>
> >> @@ -253,9 +255,21 @@ 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 (bars & BIT(bar)) {
> >> + dev_warn(&pcidev->dev, "skipping bad port
> >> BAR %d\n", bar);
> >> + continue;
> >> + }
> >
> > Will it be a real problem that multiple ports are inside one BAR but different
> offsets?
> >
> > Hao
>
> I don't think multiple ports within a single BAR is something that has
> been supported in the past. The genesis for this patch was a
> misconfigured port entry pointing to BAR0. BAR0 had already been mapped
> for the FME and remapping BAR0 failed resulting in enumeration failure.

could some products put the port in BAR0? Or multiple ports in one BAR.
As we consider this is a common driver can be reused and maintained for
a long time, so I hope that we don't put limitation setup only for some
specific products.

Hao

>
> Matthew
>
> >
> >> +
> >> start = pci_resource_start(pcidev, bar) + offset;
> >> - len = pci_resource_len(pcidev, bar) - offset;
> >> + len = pci_resource_len(pcidev, bar);
> >> + if (offset >= len) {
> >> + dev_warn(&pcidev->dev, "bad port
> >> offset %u >= %pa\n",
> >> + offset, &len);
> >> + continue;
> >> + }
> >>
> >> + len -= offset;
> >> + bars |= BIT(bar);
> >> dfl_fpga_enum_info_add_dfl(info, start, len);
> >> }
> >> } else if (dfl_feature_is_port(base)) {
> >> --
> >> 1.8.3.1
> >
> >

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