net: enetc: remove redundant num_vsi field from enetc_port_caps

The num_vsi field in struct enetc_port_caps is populated by reading the
NUM_VSI field of the ECAPR1 register, which reports the number of VSIs
supported by the ENETC4 port. When CONFIG_PCI_IOV is enabled, this value
always matches pf->total_vfs, which is obtained from the read-only
PCI_SRIOV_TOTAL_VF register via pci_sriov_get_totalvfs() during probe.
Both ECAPR1[NUM_VSI] and PCI_SRIOV_TOTAL_VF are derived from the same
IERB register EaVFRIDAR[NUM_VF] (a 4-bit field), so they are guaranteed
to be equal. When CONFIG_PCI_IOV is disabled, pci_sriov_get_totalvfs()
returns 0, but this is benign since pci_enable_sriov() is also stubbed
to return -ENODEV, so no VF can be created, and enetc4_enable_all_si()
only enables the PF SI (PSI).

Since pf->total_vfs already reflects the number of VFs that can actually
be used, and is the established convention in the sibling FSL_ENETC PF
driver, there is no need to read and cache num_vsi separately in the port
capabilities structure. Remove the num_vsi field from enetc_port_caps,
and replace all uses of pf->caps.num_vsi with pf->total_vfs in the ring
allocation, SI enable, and debugfs code paths. Note that in the MSI-X
configuration, it is still necessary to obtain the actual number of VSIs
from ECAPR1.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Link: https://patch.msgid.link/20260720014317.1059359-13-wei.fang@oss.nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Wei Fang 2026-07-20 09:43:14 +08:00 • committed by Jakub Kicinski
commit 75b136cf0f
3 changed files with 68 additions and 32 deletions