[PATCH iwl-next v8 11/11] igc: add support to get frame preemption statistics via ethtool

Faizal Rahim
2025-03-05T13:24:50Z

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>
Co-developed-by: Chwee-Lin Choong <chwee.lin.choong@intel.com>
Signed-off-by: Chwee-Lin Choong <chwee.lin.choong@intel.com>
Signed-off-by: Faizal Rahim <faizal.abdul.rahim@linux.intel.com>
---
drivers/net/ethernet/intel/igc/igc_ethtool.c | 39 ++++++++++++++++++++
drivers/net/ethernet/intel/igc/igc_regs.h | 16 ++++++++
2 files changed, 55 insertions(+)

diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index fd4b4b332309..1ed08a3fa78b 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1819,6 +1819,44 @@ 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)
+{
+ u32 ooo_frame_cnt, ooo_frag_cnt; /* Out of order statistics */
+ 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)
{
@@ -2116,6 +2154,7 @@ static const struct ethtool_ops igc_ethtool_ops = {
.self_test = igc_ethtool_diag_test,
.get_mm = igc_ethtool_get_mm,
.set_mm = igc_ethtool_set_mm,
+ .get_mm_stats = igc_ethtool_get_mm_stats,
};

void igc_ethtool_set_ops(struct net_device *netdev)
diff --git a/drivers/net/ethernet/intel/igc/igc_regs.h b/drivers/net/ethernet/intel/igc/igc_regs.h
index 12ddc5793651..f343c6bfc6be 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_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))
--
2.34.1