igc: add support to get frame preemption statistics via ethtool

Implemented "ethtool --include-statistics --show-mm" callback for IGC.

Tested preemption scenario to check preemption statistics:
1) Trigger verification handshake on both boards:
    $ sudo ethtool --set-mm enp1s0 pmac-enabled on
    $ sudo ethtool --set-mm enp1s0 tx-enabled on
    $ sudo ethtool --set-mm enp1s0 verify-enabled on
2) Set preemptible or express queue in taprio for tx board:
    $ sudo tc qdisc replace dev enp1s0 parent root handle 100 taprio \
      num_tc 4 map 3 2 1 0 3 3 3 3 3 3 3 3 3 3 3 3 \
      queues 1@0 1@1 1@2 1@3 base-time 0 sched-entry S F 100000 \
      fp E E P P
3) Send large size packets on preemptible queue
4) Send small size packets on express queue to preempt packets in
   preemptible queue
5) Show preemption statistics on the receiving board:
   $ ethtool --include-statistics --show-mm enp1s0
     MAC Merge layer state for enp1s0:
     pMAC enabled: on
     TX enabled: on
     TX active: on
     TX minimum fragment size: 64
     RX minimum fragment size: 60
     Verify enabled: on
     Verify time: 128
     Max verify time: 128
     Verification status: SUCCEEDED
     Statistics:
      MACMergeFrameAssErrorCount: 0
      MACMergeFrameSmdErrorCount: 0
      MACMergeFrameAssOkCount: 511
      MACMergeFragCountRx: 764
      MACMergeFragCountTx: 0
      MACMergeHoldCount: 0

Co-developed-by: Vinicius Costa Gomes <[email protected]>
Signed-off-by: Vinicius Costa Gomes <[email protected]>
Co-developed-by: Chwee-Lin Choong <[email protected]>
Signed-off-by: Chwee-Lin Choong <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Signed-off-by: Faizal Rahim <[email protected]>
Tested-by: Mor Bar-Gabay <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: Faizal Rahim

drivers/net/ethernet/intel/igc/igc_ethtool.c

@@ -1819,6 +1819,46 @@ static int igc_ethtool_set_mm(struct net_device *netdev,
 	return igc_tsn_offload_apply(adapter);
 }
 
+/**
+ * igc_ethtool_get_frame_ass_error - Get the frame assembly error count.
+ * @reg_value: Register value for IGC_PRMEXCPRCNT
+ * Return: The count of frame assembly errors.
+ */
+static u64 igc_ethtool_get_frame_ass_error(u32 reg_value)
+{
+	/* Out of order statistics */
+	u32 ooo_frame_cnt, ooo_frag_cnt;
+	u32 miss_frame_frag_cnt;
+
+	ooo_frame_cnt = FIELD_GET(IGC_PRMEXCPRCNT_OOO_FRAME_CNT, reg_value);
+	ooo_frag_cnt = FIELD_GET(IGC_PRMEXCPRCNT_OOO_FRAG_CNT, reg_value);
+	miss_frame_frag_cnt = FIELD_GET(IGC_PRMEXCPRCNT_MISS_FRAME_FRAG_CNT,
+					reg_value);
+
+	return ooo_frame_cnt + ooo_frag_cnt + miss_frame_frag_cnt;
+}
+
+static u64 igc_ethtool_get_frame_smd_error(u32 reg_value)
+{
+	return FIELD_GET(IGC_PRMEXCPRCNT_OOO_SMDC, reg_value);
+}
+
+static void igc_ethtool_get_mm_stats(struct net_device *dev,
+				     struct ethtool_mm_stats *stats)
+{
+	struct igc_adapter *adapter = netdev_priv(dev);
+	struct igc_hw *hw = &adapter->hw;
+	u32 reg_value;
+
+	reg_value = rd32(IGC_PRMEXCPRCNT);
+
+	stats->MACMergeFrameAssErrorCount = igc_ethtool_get_frame_ass_error(reg_value);
+	stats->MACMergeFrameSmdErrorCount = igc_ethtool_get_frame_smd_error(reg_value);
+	stats->MACMergeFrameAssOkCount = rd32(IGC_PRMPTDRCNT);
+	stats->MACMergeFragCountRx = rd32(IGC_PRMEVNTRCNT);
+	stats->MACMergeFragCountTx = rd32(IGC_PRMEVNTTCNT);
+}
+
 static int igc_ethtool_get_link_ksettings(struct net_device *netdev,
 					  struct ethtool_link_ksettings *cmd)
 {
@@ -2115,6 +2155,7 @@ static const struct ethtool_ops igc_ethtool_ops = {
 	.set_link_ksettings	= igc_ethtool_set_link_ksettings,
 	.self_test		= igc_ethtool_diag_test,
 	.get_mm			= igc_ethtool_get_mm,
+	.get_mm_stats		= igc_ethtool_get_mm_stats,
 	.set_mm			= igc_ethtool_set_mm,
 };
 

drivers/net/ethernet/intel/igc/igc_regs.h

@@ -222,6 +222,22 @@
 
 #define IGC_FTQF(_n)	(0x059E0 + (4 * (_n)))  /* 5-tuple Queue Fltr */
 
+/* Time sync registers - preemption statistics */
+#define IGC_PRMPTDRCNT		0x04284	/* Good RX Preempted Packets */
+#define IGC_PRMEVNTTCNT		0x04298	/* TX Preemption event counter */
+#define IGC_PRMEVNTRCNT		0x0429C	/* RX Preemption event counter */
+
+ /* Preemption Exception Counter */
+ #define IGC_PRMEXCPRCNT				0x42A0
+/* Received out of order packets with SMD-C */
+#define IGC_PRMEXCPRCNT_OOO_SMDC			0x000000FF
+/* Received out of order packets with SMD-C and wrong Frame CNT */
+#define IGC_PRMEXCPRCNT_OOO_FRAME_CNT			0x0000FF00
+/* Received out of order packets with SMD-C and wrong Frag CNT */
+#define IGC_PRMEXCPRCNT_OOO_FRAG_CNT			0x00FF0000
+/* Received packets with SMD-S and wrong Frag CNT and Frame CNT */
+#define IGC_PRMEXCPRCNT_MISS_FRAME_FRAG_CNT		0xFF000000
+
 /* Transmit Scheduling Registers */
 #define IGC_TQAVCTRL		0x3570
 #define IGC_TXQCTL(_n)		(0x3344 + 0x4 * (_n))