[PATCH iwl-next v5 8/9] igc: Add support to get frame preemption statistics via ethtool

[Faizal Rahim <faizal.abdul.rahim@linux.intel.com>]

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 <vinicius.gomes@intel.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
---
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 36 ++++++++++++++++++++
 drivers/net/ethernet/intel/igc/igc_regs.h    | 16 +++++++++
 2 files changed, 52 insertions(+)

diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index 7f0052e0d50c..97a1194399b1 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1819,6 +1819,41 @@ 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.
+ * @dev: Pointer to the net_device structure.
+ * Return: The count of frame assembly errors.
+ */
+static u64 igc_ethtool_get_frame_ass_error(struct net_device *dev)
+{
+	struct igc_adapter *adapter = netdev_priv(dev);
+	u32 ooo_smdc, ooo_frame_cnt, ooo_frag_cnt; /* Out of order statistics */
+	struct igc_hw *hw = &adapter->hw;
+	u32 miss_frame_frag_cnt;
+	u32 reg_value;
+
+	reg_value = rd32(IGC_PRMEXPRCNT);
+	ooo_smdc = FIELD_GET(IGC_PRMEXPRCNT_OOO_SMDC, reg_value);
+	ooo_frame_cnt = FIELD_GET(IGC_PRMEXPRCNT_OOO_FRAME_CNT, reg_value);
+	ooo_frag_cnt = FIELD_GET(IGC_PRMEXPRCNT_OOO_FRAG_CNT, reg_value);
+	miss_frame_frag_cnt = FIELD_GET(IGC_PRMEXPRCNT_MISS_FRAME_FRAG_CNT,
+					reg_value);
+
+	return ooo_smdc + ooo_frame_cnt + ooo_frag_cnt + miss_frame_frag_cnt;
+}
+
+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;
+
+	stats->MACMergeFrameAssErrorCount = igc_ethtool_get_frame_ass_error(dev);
+	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)
 {
@@ -2108,6 +2143,7 @@ static const struct ethtool_ops igc_ethtool_ops = {
 	.get_channels		= igc_ethtool_get_channels,
 	.get_mm			= igc_ethtool_get_mm,
 	.set_mm			= igc_ethtool_set_mm,
+	.get_mm_stats		= igc_ethtool_get_mm_stats,
 	.set_channels		= igc_ethtool_set_channels,
 	.get_priv_flags		= igc_ethtool_get_priv_flags,
 	.set_priv_flags		= igc_ethtool_set_priv_flags,
diff --git a/drivers/net/ethernet/intel/igc/igc_regs.h b/drivers/net/ethernet/intel/igc/igc_regs.h
index 12ddc5793651..41dbfb07eb2f 100644
--- a/drivers/net/ethernet/intel/igc/igc_regs.h
+++ b/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_PRMEXPRCNT					0x42A0
+/* Received out of order packets with SMD-C */
+#define IGC_PRMEXPRCNT_OOO_SMDC				0x000000FF
+/* Received out of order packets with SMD-C and wrong Frame CNT */
+#define IGC_PRMEXPRCNT_OOO_FRAME_CNT			0x0000FF00
+/* Received out of order packets with SMD-C and wrong Frag CNT */
+#define IGC_PRMEXPRCNT_OOO_FRAG_CNT			0x00FF0000
+/* Received packets with SMD-S and wrong Frag CNT and Frame CNT */
+#define IGC_PRMEXPRCNT_MISS_FRAME_FRAG_CNT		0xFF000000
+
 /* Transmit Scheduling Registers */
 #define IGC_TQAVCTRL		0x3570
 #define IGC_TXQCTL(_n)		(0x3344 + 0x4 * (_n))
-- 
2.34.1