net: systemport: Fix RUNT MIB counter register offset calculation

In UniMAC hardware, there is a 0xC byte gap between the RX MIB counters
and the TX MIB counters, and a second 0xC byte gap between the TX MIB
counters and the RX RUNT MIB counters.

In bcm_sysport_update_mib_counters(), 'offset' was only set to
UMAC_MIB_STAT_OFFSET (0xC) for all non-RX counters, omitting the second
0xC gap for BCM_SYSPORT_STAT_RUNT counters. As a result, all 4 RUNT MIB
counters were read from unmapped gap register space.

Fix this by setting offset to 2 * UMAC_MIB_STAT_OFFSET (0x18) when
reading BCM_SYSPORT_STAT_RUNT counters.

Fixes: 80105befdb ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver")
Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20260922232440.598918-6-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Florian Fainelli 2026-09-22 16:24:35 -07:00 • committed by Jakub Kicinski
commit 242935adfe