[PATCH net-next v2 4/4] net/mlx5e: Report RS-FEC histogram statistics via ethtool

[Vadim Fedorenko <vadim.fedorenko@linux.dev>]

From: Carolina Jubran <cjubran@nvidia.com>

Add support for reporting RS-FEC histogram counters by reading them
from the RS_FEC_HISTOGRAM_GROUP in the PPCNT register.

Co-developed-by: Yael Chemla <ychemla@nvidia.com>
Signed-off-by: Yael Chemla <ychemla@nvidia.com>
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Yael Chemla <ychemla@nvidia.com>
Signed-off-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
---
 .../ethernet/mellanox/mlx5/core/en_stats.c    | 33 ++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
index 476689cb0c1f..1da439dda323 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
@@ -1529,15 +1529,46 @@ fec_rs_histogram_fill_ranges(struct mlx5e_priv *priv,
 	return num_of_bins;
 }
 
+static void fec_rs_histogram_fill_stats(struct mlx5e_priv *priv,
+					u8 num_of_bins,
+					struct ethtool_fec_hist *hist)
+{
+	struct mlx5_core_dev *mdev = priv->mdev;
+	u32 out[MLX5_ST_SZ_DW(ppcnt_reg)] = {0};
+	u32 in[MLX5_ST_SZ_DW(ppcnt_reg)] = {0};
+	int sz = MLX5_ST_SZ_BYTES(ppcnt_reg);
+	void *rs_histogram_cntrs;
+
+	MLX5_SET(ppcnt_reg, in, local_port, 1);
+	MLX5_SET(ppcnt_reg, in, grp, MLX5_RS_FEC_HISTOGRAM_GROUP);
+	if (mlx5_core_access_reg(mdev, in, sz, out, sz, MLX5_REG_PPCNT, 0, 0))
+		return;
+
+	rs_histogram_cntrs = MLX5_ADDR_OF(ppcnt_reg, out,
+					  counter_set.rs_histogram_cntrs);
+	/* Guaranteed that num_of_bins is less than MLX5E_FEC_RS_HIST_MAX
+	 * by fec_rs_histogram_fill_ranges().
+	 */
+	for (int i = 0; i < num_of_bins; i++) {
+		hist->values[i].bin_value = MLX5_GET64(rs_histogram_cntrs,
+						       rs_histogram_cntrs,
+						       hist[i]);
+	}
+}
+
 static void fec_set_histograms_stats(struct mlx5e_priv *priv, int mode,
 				     struct ethtool_fec_hist *hist)
 {
+	u8 num_of_bins;
+
 	switch (mode) {
 	case MLX5E_FEC_RS_528_514:
 	case MLX5E_FEC_RS_544_514:
 	case MLX5E_FEC_LLRS_272_257_1:
 	case MLX5E_FEC_RS_544_514_INTERLEAVED_QUAD:
-		fec_rs_histogram_fill_ranges(priv, &hist->ranges);
+		num_of_bins = fec_rs_histogram_fill_ranges(priv, &hist->ranges);
+		if (num_of_bins)
+			fec_rs_histogram_fill_stats(priv, num_of_bins, hist);
 		break;
 	default:
 		return;
-- 
2.47.3