[PATCH net] octeontx2-af: skip absent MCS blocks in PTP configuration

[Slavin Liu]

A successfully probed RPM does not imply a matching MCS block.
Check the independent MCS lookup before accessing PEX registers.

Detected by static analysis and reviewed with AI-assisted source auditing.

Fixes: 65cdc2b637a5 ("octeontx2-af: mcs: Config parser to skip 8B header")
Assisted-by: LLM
Signed-off-by: Slavin Liu <bolin.liu@xxxxxxxxxx>
---
 drivers/net/ethernet/marvell/octeontx2/af/mcs_rvu_if.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/mcs_rvu_if.c b/drivers/net/ethernet/marvell/octeontx2/af/mcs_rvu_if.c
index fce22e314cac..5e24d43d5fc7 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/mcs_rvu_if.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/mcs_rvu_if.c
@@ -50,6 +50,8 @@ void rvu_mcs_ptp_cfg(struct rvu *rvu, u8 rpm_id, u8 lmac_id, bool ena)
 	/* CNF10K-B */
 	if (rvu->mcs_blk_cnt > 1) {
 		mcs = mcs_get_pdata(rpm_id);
+		if (!mcs)
+			return;
 		cfg = mcs_reg_read(mcs, MCSX_PEX_RX_SLAVE_PEX_CONFIGURATION);
 		if (ena)
 			cfg |= BIT_ULL(lmac_id);