octeontx2-af: RPM: fix stale RSFEC counters

The earlier patch sets the 'Stats control register' for RPM
receive/transmit statistics instead of RSFEC statistics,
causing the driver to return stale FEC counters.

Fixes: 84ad364 ("octeontx2-af: Add FEC stats for RPM/RPM_USX block")
Signed-off-by: Hariprasad Kelam <hkelam@marvell.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Hariprasad Kelam

drivers/net/ethernet/marvell/octeontx2/af/rpm.c

@@ -699,6 +699,10 @@ int rpm_get_fec_stats(void *rpmd, int lmac_id, struct cgx_fec_stats_rsp *rsp)
 	if (rpm->lmac_idmap[lmac_id]->link_info.fec == OTX2_FEC_NONE)
 		return 0;
 
+	/* latched registers FCFECX_CW_HI/RSFEC_STAT_FAST_DATA_HI_CDC are common
+	 * for all counters. Acquire lock to ensure serialized reads
+	 */
+	mutex_lock(&rpm->lock);
 	if (rpm->lmac_idmap[lmac_id]->link_info.fec == OTX2_FEC_BASER) {
 		val_lo = rpm_read(rpm, lmac_id, RPMX_MTI_FCFECX_VL0_CCW_LO);
 		val_hi = rpm_read(rpm, lmac_id, RPMX_MTI_FCFECX_CW_HI);
@@ -725,20 +729,21 @@ int rpm_get_fec_stats(void *rpmd, int lmac_id, struct cgx_fec_stats_rsp *rsp)
 		}
 	} else {
 		/* enable RS-FEC capture */
-		cfg = rpm_read(rpm, 0, RPMX_MTI_STAT_STATN_CONTROL);
+		cfg = rpm_read(rpm, 0, RPMX_MTI_RSFEC_STAT_STATN_CONTROL);
 		cfg |= RPMX_RSFEC_RX_CAPTURE | BIT(lmac_id);
-		rpm_write(rpm, 0, RPMX_MTI_STAT_STATN_CONTROL, cfg);
+		rpm_write(rpm, 0, RPMX_MTI_RSFEC_STAT_STATN_CONTROL, cfg);
 
 		val_lo = rpm_read(rpm, 0,
 				  RPMX_MTI_RSFEC_STAT_COUNTER_CAPTURE_2);
-		val_hi = rpm_read(rpm, 0, RPMX_MTI_STAT_DATA_HI_CDC);
+		val_hi = rpm_read(rpm, 0, RPMX_MTI_RSFEC_STAT_FAST_DATA_HI_CDC);
 		rsp->fec_corr_blks = (val_hi << 32 | val_lo);
 
 		val_lo = rpm_read(rpm, 0,
 				  RPMX_MTI_RSFEC_STAT_COUNTER_CAPTURE_3);
-		val_hi = rpm_read(rpm, 0, RPMX_MTI_STAT_DATA_HI_CDC);
+		val_hi = rpm_read(rpm, 0, RPMX_MTI_RSFEC_STAT_FAST_DATA_HI_CDC);
 		rsp->fec_uncorr_blks = (val_hi << 32 | val_lo);
 	}
+	mutex_unlock(&rpm->lock);
 
 	return 0;
 }

drivers/net/ethernet/marvell/octeontx2/af/rpm.h

@@ -84,9 +84,11 @@
 /* FEC stats */
 #define RPMX_MTI_STAT_STATN_CONTROL			0x10018
 #define RPMX_MTI_STAT_DATA_HI_CDC			0x10038
-#define RPMX_RSFEC_RX_CAPTURE				BIT_ULL(27)
+#define RPMX_RSFEC_RX_CAPTURE				BIT_ULL(28)
 #define RPMX_CMD_CLEAR_RX				BIT_ULL(30)
 #define RPMX_CMD_CLEAR_TX				BIT_ULL(31)
+#define RPMX_MTI_RSFEC_STAT_STATN_CONTROL               0x40018
+#define RPMX_MTI_RSFEC_STAT_FAST_DATA_HI_CDC            0x40000
 #define RPMX_MTI_RSFEC_STAT_COUNTER_CAPTURE_2		0x40050
 #define RPMX_MTI_RSFEC_STAT_COUNTER_CAPTURE_3		0x40058
 #define RPMX_MTI_FCFECX_VL0_CCW_LO			0x38618