We enumerate devices by attempting config reads to the Vendor ID of each
possible device. On conventional PCI, if no device responds, the read
terminates with a Master Abort (PCI r3.0, sec 6.1). On PCIe, the config
read is terminated as an Unsupported Request (PCIe r6.0, sec 2.3.2,
7.5.1.3.7). In either case, if the read addressed a device below a bridge,
it is logged by setting "Received Master Abort" in the bridge Secondary
Status register.
Clear any errors logged in the Secondary Status register after enumeration.
Link: https://lore.kernel.org/r/20240116143258.483235-1-vidyas@nvidia.com
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
[bhelgaas: simplify commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
7bf9d2af7e