[PATCH] net: stmmac: xgmac: report L3/L4 filter match count in ethtool stats

[muhammad.nazim.amirul.nazle.asmade at altera.com]

From: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade at altera.com>

Read the L3FM and L4FM bits from the RX descriptor status word (RDES2)
and increment the corresponding ethtool statistics counters. This allows
users to observe L3/L4 filter hit rates via ethtool -S.

Signed-off-by: Rohan G Thomas <rohan.g.thomas at altera.com>
Signed-off-by: Nazim Amirul <muhammad.nazim.amirul.nazle.asmade at altera.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h       | 2 ++
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
index 51943705a2b0..95fdf3133208 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
@@ -429,6 +429,8 @@
 #define XGMAC_TDES3_VLTV		BIT(16)
 #define XGMAC_TDES3_VT			GENMASK(15, 0)
 #define XGMAC_TDES3_FL			GENMASK(14, 0)
+#define XGMAC_RDES2_L4FM		BIT(28)
+#define XGMAC_RDES2_L3FM		BIT(27)
 #define XGMAC_RDES2_HL			GENMASK(9, 0)
 #define XGMAC_RDES3_OWN			BIT(31)
 #define XGMAC_RDES3_CTXT		BIT(30)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
index b5f200a87484..6719ac6e395b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_descs.c
@@ -27,6 +27,7 @@ static int dwxgmac2_get_rx_status(struct stmmac_extra_stats *x,
 				  struct dma_desc *p)
 {
 	u32 rdes3 = le32_to_cpu(p->des3);
+	u32 rdes2 = le32_to_cpu(p->des2);
 
 	if (unlikely(rdes3 & XGMAC_RDES3_OWN))
 		return dma_own;
@@ -37,6 +38,11 @@ static int dwxgmac2_get_rx_status(struct stmmac_extra_stats *x,
 	if (unlikely((rdes3 & XGMAC_RDES3_ES) && (rdes3 & XGMAC_RDES3_LD)))
 		return discard_frame;
 
+	if (rdes2 & XGMAC_RDES2_L3FM)
+		x->l3_filter_match++;
+	if (rdes2 & XGMAC_RDES2_L4FM)
+		x->l4_filter_match++;
+
 	return good_frame;
 }
 
-- 
2.43.7