ethtool: add FEC bins histogram report

IEEE 802.3ck-2022 defines counters for FEC bins and 802.3df-2024
clarifies it a bit further. Implement reporting interface through as
addition to FEC stats available in ethtool. Drivers can leave bin
counter uninitialized if per-lane values are provided. In this case the
core will recalculate summ for the bin.

Signed-off-by: Vadim Fedorenko <[e-mail]>
Reviewed-by: Aleksandr Loktionov <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/netlink/specs/ethtool.yaml

···
         type: nest
         nested-attributes: tunnel-udp
   -
+    name: fec-hist
+    attr-cnt-name: --ethtool-a-fec-hist-cnt
+    attributes:
+      -
+        name: pad
+        type: pad
+      -
+        name: bin-low
+        type: u32
+        doc: Low bound of FEC bin (inclusive)
+      -
+        name: bin-high
+        type: u32
+        doc: High bound of FEC bin (inclusive)
+      -
+        name: bin-val
+        type: uint
+        doc: Error count in the bin (optional if per-lane values exist)
+      -
+        name: bin-val-per-lane
+        type: binary
+        sub-type: u64
+        doc: An array of per-lane error counters in the bin (optional)
+  -
     name: fec-stat
     attr-cnt-name: __ethtool-a-fec-stat-cnt
     attributes:
···
         name: corr-bits
         type: binary
         sub-type: u64
+      -
+        name: hist
+        type: nest
+        multi-attr: True
+        nested-attributes: fec-hist
   -
     name: fec
     attr-cnt-name: __ethtool-a-fec-cnt

Documentation/networking/ethtool-netlink.rst

···
 .. kernel-doc:: include/linux/ethtool.h
     :identifiers: ethtool_fec_stats
 
+Statistics may have FEC bins histogram attribute ``ETHTOOL_A_FEC_STAT_HIST``
+as defined in IEEE 802.3ck-2022 and 802.3df-2024. Nested attributes will have
+the range of FEC errors in the bin (inclusive) and the amount of error events
+in the bin.
+
 FEC_SET
 =======
 

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

···
 }
 
 static void bnxt_get_fec_stats(struct net_device *dev,
-			       struct ethtool_fec_stats *fec_stats)
+			       struct ethtool_fec_stats *fec_stats,
+			       struct ethtool_fec_hist *hist)
 {
 	struct bnxt *bp = netdev_priv(dev);
 	u64 *rx;

drivers/net/ethernet/fungible/funeth/funeth_ethtool.c

···
 }
 
 static void fun_get_fec_stats(struct net_device *netdev,
-			      struct ethtool_fec_stats *stats)
+			      struct ethtool_fec_stats *stats,
+			      struct ethtool_fec_hist *hist)
 {
 	const struct funeth_priv *fp = netdev_priv(netdev);
 

drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c

···
 }
 
 static void hns3_get_fec_stats(struct net_device *netdev,
-			       struct ethtool_fec_stats *fec_stats)
+			       struct ethtool_fec_stats *fec_stats,
+			       struct ethtool_fec_hist *hist)
 {
 	struct hnae3_handle *handle = hns3_get_handle(netdev);
 	struct hnae3_ae_dev *ae_dev = hns3_get_ae_dev(handle);

drivers/net/ethernet/intel/ice/ice_ethtool.c

···
  * ice_get_fec_stats - returns FEC correctable, uncorrectable stats per netdev
  * @netdev: network interface device structure
  * @fec_stats: buffer to hold FEC statistics for given port
+ * @hist: buffer to put FEC histogram statistics for given port
  *
  */
 static void ice_get_fec_stats(struct net_device *netdev,
-			      struct ethtool_fec_stats *fec_stats)
+			      struct ethtool_fec_stats *fec_stats,
+			      struct ethtool_fec_hist *hist)
 {
 	struct ice_netdev_priv *np = netdev_priv(netdev);
 	struct ice_port_topology port_topology;

drivers/net/ethernet/marvell/octeontx2/nic/otx2_ethtool.c

···
 }
 
 static void otx2_get_fec_stats(struct net_device *netdev,
-			       struct ethtool_fec_stats *fec_stats)
+			       struct ethtool_fec_stats *fec_stats,
+			       struct ethtool_fec_hist *hist)
 {
 	struct otx2_nic *pfvf = netdev_priv(netdev);
 	struct cgx_fw_data *rsp;

drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c

···
 }
 
 static void mlx5e_get_fec_stats(struct net_device *netdev,
-				struct ethtool_fec_stats *fec_stats)
+				struct ethtool_fec_stats *fec_stats,
+				struct ethtool_fec_hist *hist)
 {
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 

drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c

···
 
 static void
 fbnic_get_fec_stats(struct net_device *netdev,
-		    struct ethtool_fec_stats *fec_stats)
+		    struct ethtool_fec_stats *fec_stats,
+		    struct ethtool_fec_hist *hist)
 {
 	struct fbnic_net *fbn = netdev_priv(netdev);
 	struct fbnic_phy_stats *phy_stats;

drivers/net/ethernet/sfc/ethtool.c

···
 }
 
 static void efx_ethtool_get_fec_stats(struct net_device *net_dev,
-				      struct ethtool_fec_stats *fec_stats)
+				      struct ethtool_fec_stats *fec_stats,
+				      struct ethtool_fec_hist *hist)
 {
 	struct efx_nic *efx = efx_netdev_priv(net_dev);
 

drivers/net/ethernet/sfc/siena/ethtool.c

···
 }
 
 static void efx_ethtool_get_fec_stats(struct net_device *net_dev,
-				      struct ethtool_fec_stats *fec_stats)
+				      struct ethtool_fec_stats *fec_stats,
+				      struct ethtool_fec_hist *hist)
 {
 	struct efx_nic *efx = netdev_priv(net_dev);
 

drivers/net/netdevsim/ethtool.c

···
 	return 0;
 }
 
+static const struct ethtool_fec_hist_range netdevsim_fec_ranges[] = {
+	{ 0, 0},
+	{ 1, 3},
+	{ 4, 7},
+	{ 0, 0}
+};
+
 static void
-nsim_get_fec_stats(struct net_device *dev, struct ethtool_fec_stats *fec_stats)
+nsim_get_fec_stats(struct net_device *dev, struct ethtool_fec_stats *fec_stats,
+		   struct ethtool_fec_hist *hist)
 {
+	struct ethtool_fec_hist_value *values = hist->values;
+
+	hist->ranges = netdevsim_fec_ranges;
+
 	fec_stats->corrected_blocks.total = 123;
 	fec_stats->uncorrectable_blocks.total = 4;
+
+	values[0].per_lane[0] = 125;
+	values[0].per_lane[1] = 120;
+	values[0].per_lane[2] = 100;
+	values[0].per_lane[3] = 100;
+	values[1].sum = 12;
+	values[2].sum = 2;
+	values[2].per_lane[0] = 2;
+	values[2].per_lane[1] = 0;
+	values[2].per_lane[2] = 0;
+	values[2].per_lane[3] = 0;
 }
 
 static int nsim_get_ts_info(struct net_device *dev,

include/linux/ethtool.h

···
 };
 
 #define ETHTOOL_MAX_LANES	8
+/**
+ * IEEE 802.3ck/df defines 16 bins for FEC histogram plus one more for
+ * the end-of-list marker, total 17 items
+ */
+#define ETHTOOL_FEC_HIST_MAX	17
+/**
+ * struct ethtool_fec_hist_range - error bits range for FEC histogram
+ * statistics
+ * @low: low bound of the bin (inclusive)
+ * @high: high bound of the bin (inclusive)
+ */
+struct ethtool_fec_hist_range {
+	u16 low;
+	u16 high;
+};
 
+struct ethtool_fec_hist {
+	struct ethtool_fec_hist_value {
+		u64 sum;
+		u64 per_lane[ETHTOOL_MAX_LANES];
+	} values[ETHTOOL_FEC_HIST_MAX];
+	const struct ethtool_fec_hist_range *ranges;
+};
 /**
  * struct ethtool_fec_stats - statistics for IEEE 802.3 FEC
  * @corrected_blocks: number of received blocks corrected by FEC
···
 	int	(*set_link_ksettings)(struct net_device *,
 				      const struct ethtool_link_ksettings *);
 	void	(*get_fec_stats)(struct net_device *dev,
-				 struct ethtool_fec_stats *fec_stats);
+				 struct ethtool_fec_stats *fec_stats,
+				 struct ethtool_fec_hist *hist);
 	int	(*get_fecparam)(struct net_device *,
 				      struct ethtool_fecparam *);
 	int	(*set_fecparam)(struct net_device *,

include/uapi/linux/ethtool_netlink_generated.h

···
 };
 
 enum {
+	ETHTOOL_A_FEC_HIST_PAD = 1,
+	ETHTOOL_A_FEC_HIST_BIN_LOW,
+	ETHTOOL_A_FEC_HIST_BIN_HIGH,
+	ETHTOOL_A_FEC_HIST_BIN_VAL,
+	ETHTOOL_A_FEC_HIST_BIN_VAL_PER_LANE,
+
+	__ETHTOOL_A_FEC_HIST_CNT,
+	ETHTOOL_A_FEC_HIST_MAX = (__ETHTOOL_A_FEC_HIST_CNT - 1)
+};
+
+enum {
 	ETHTOOL_A_FEC_STAT_UNSPEC,
 	ETHTOOL_A_FEC_STAT_PAD,
 	ETHTOOL_A_FEC_STAT_CORRECTED,
 	ETHTOOL_A_FEC_STAT_UNCORR,
 	ETHTOOL_A_FEC_STAT_CORR_BITS,
+	ETHTOOL_A_FEC_STAT_HIST,
 
 	__ETHTOOL_A_FEC_STAT_CNT,
 	ETHTOOL_A_FEC_STAT_MAX = (__ETHTOOL_A_FEC_STAT_CNT - 1)

net/ethtool/fec.c

···
 		u64 stats[1 + ETHTOOL_MAX_LANES];
 		u8 cnt;
 	} corr, uncorr, corr_bits;
+	struct ethtool_fec_hist fec_stat_hist;
 };
 
 #define FEC_REPDATA(__reply_base) \
···
 		struct ethtool_fec_stats stats;
 
 		ethtool_stats_init((u64 *)&stats, sizeof(stats) / 8);
-		dev->ethtool_ops->get_fec_stats(dev, &stats);
+		ethtool_stats_init((u64 *)data->fec_stat_hist.values,
+				   sizeof(data->fec_stat_hist.values) / 8);
+		dev->ethtool_ops->get_fec_stats(dev, &stats,
+						&data->fec_stat_hist);
 
 		fec_stats_recalc(&data->corr, &stats.corrected_blocks);
 		fec_stats_recalc(&data->uncorr, &stats.uncorrectable_blocks);
···
 	len += nla_total_size(sizeof(u8)) +	/* _FEC_AUTO */
 	       nla_total_size(sizeof(u32));	/* _FEC_ACTIVE */
 
-	if (req_base->flags & ETHTOOL_FLAG_STATS)
+	if (req_base->flags & ETHTOOL_FLAG_STATS) {
 		len += 3 * nla_total_size_64bit(sizeof(u64) *
 						(1 + ETHTOOL_MAX_LANES));
+		/* add FEC bins information */
+		len += (nla_total_size(0) +  /* _A_FEC_HIST */
+			nla_total_size(4) +  /* _A_FEC_HIST_BIN_LOW */
+			nla_total_size(4) +  /* _A_FEC_HIST_BIN_HI */
+			/* _A_FEC_HIST_BIN_VAL + per-lane values */
+			nla_total_size_64bit(sizeof(u64)) +
+			nla_total_size_64bit(sizeof(u64) * ETHTOOL_MAX_LANES)) *
+			ETHTOOL_FEC_HIST_MAX;
+	}
 
 	return len;
+}
+
+static int fec_put_hist(struct sk_buff *skb,
+			const struct ethtool_fec_hist *hist)
+{
+	const struct ethtool_fec_hist_range *ranges = hist->ranges;
+	const struct ethtool_fec_hist_value *values = hist->values;
+	struct nlattr *nest;
+	int i, j;
+	u64 sum;
+
+	if (!ranges)
+		return 0;
+
+	for (i = 0; i < ETHTOOL_FEC_HIST_MAX; i++) {
+		if (i && !ranges[i].low && !ranges[i].high)
+			break;
+
+		if (WARN_ON_ONCE(values[i].sum == ETHTOOL_STAT_NOT_SET &&
+				 values[i].per_lane[0] == ETHTOOL_STAT_NOT_SET))
+			break;
+
+		nest = nla_nest_start(skb, ETHTOOL_A_FEC_STAT_HIST);
+		if (!nest)
+			return -EMSGSIZE;
+
+		if (nla_put_u32(skb, ETHTOOL_A_FEC_HIST_BIN_LOW,
+				ranges[i].low) ||
+		    nla_put_u32(skb, ETHTOOL_A_FEC_HIST_BIN_HIGH,
+				ranges[i].high))
+			goto err_cancel_hist;
+		sum = 0;
+		for (j = 0; j < ETHTOOL_MAX_LANES; j++) {
+			if (values[i].per_lane[j] == ETHTOOL_STAT_NOT_SET)
+				break;
+			sum += values[i].per_lane[j];
+		}
+		if (nla_put_uint(skb, ETHTOOL_A_FEC_HIST_BIN_VAL,
+				 values[i].sum == ETHTOOL_STAT_NOT_SET ?
+				 sum : values[i].sum))
+			goto err_cancel_hist;
+		if (j && nla_put_64bit(skb, ETHTOOL_A_FEC_HIST_BIN_VAL_PER_LANE,
+				       sizeof(u64) * j,
+				       values[i].per_lane,
+				       ETHTOOL_A_FEC_HIST_PAD))
+			goto err_cancel_hist;
+
+		nla_nest_end(skb, nest);
+	}
+
+	return 0;
+
+err_cancel_hist:
+	nla_nest_cancel(skb, nest);
+	return -EMSGSIZE;
 }
 
 static int fec_put_stats(struct sk_buff *skb, const struct fec_reply_data *data)
···
 	    nla_put_64bit(skb, ETHTOOL_A_FEC_STAT_CORR_BITS,
 			  sizeof(u64) * data->corr_bits.cnt,
 			  data->corr_bits.stats, ETHTOOL_A_FEC_STAT_PAD))
+		goto err_cancel;
+
+	if (fec_put_hist(skb, &data->fec_stat_hist))
 		goto err_cancel;
 
 	nla_nest_end(skb, nest);