mlxsw: spectrum_acl: Implement basic ERP rehash hits creation

Introduce an initial implementation of rehash logic in ERP code.
Currently, the rehash is considered as needed only in case number of
roots in the hints is smaller than the number of roots actually in use.
In that case return hints pointer and let it be obtained through the
callpath through the Spectrum-2 TCAM op.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 74 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
index 302070a74f2e..013ab43a7727 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_erp.c
@@ -1370,6 +1370,80 @@ mlxsw_sp_acl_erp_region_param_init(struct mlxsw_sp_acl_atcam_region *aregion)
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(pererp), pererp_pl);
 }
 
+static int
+mlxsw_sp_acl_erp_hints_check(struct mlxsw_sp *mlxsw_sp,
+			     struct mlxsw_sp_acl_atcam_region *aregion,
+			     struct objagg_hints *hints, bool *p_rehash_needed)
+{
+	struct objagg *objagg = aregion->erp_table->objagg;
+	const struct objagg_stats *ostats;
+	const struct objagg_stats *hstats;
+	int err;
+
+	*p_rehash_needed = false;
+
+	ostats = objagg_stats_get(objagg);
+	if (IS_ERR(ostats)) {
+		dev_err_ratelimited(mlxsw_sp->bus_info->dev, "Failed to get ERP stats\n");
+		return PTR_ERR(ostats);
+	}
+
+	hstats = objagg_hints_stats_get(hints);
+	if (IS_ERR(hstats)) {
+		dev_err_ratelimited(mlxsw_sp->bus_info->dev, "Failed to get ERP hints stats\n");
+		err = PTR_ERR(hstats);
+		goto err_hints_stats_get;
+	}
+
+	/* Very basic criterion for now. */
+	if (hstats->root_count < ostats->root_count)
+		*p_rehash_needed = true;
+
+	err = 0;
+
+	objagg_stats_put(hstats);
+err_hints_stats_get:
+	objagg_stats_put(ostats);
+	return err;
+}
+
+void *
+mlxsw_sp_acl_erp_rehash_hints_get(struct mlxsw_sp_acl_atcam_region *aregion)
+{
+	struct mlxsw_sp *mlxsw_sp = aregion->region->mlxsw_sp;
+	struct objagg_hints *hints;
+	bool rehash_needed;
+	int err;
+
+	hints = objagg_hints_get(aregion->erp_table->objagg,
+				 OBJAGG_OPT_ALGO_SIMPLE_GREEDY);
+	if (IS_ERR(hints)) {
+		dev_err_ratelimited(mlxsw_sp->bus_info->dev, "Failed to create ERP hints\n");
+		return ERR_CAST(hints);
+	}
+	err = mlxsw_sp_acl_erp_hints_check(mlxsw_sp, aregion, hints,
+					   &rehash_needed);
+	if (err)
+		goto errout;
+
+	if (!rehash_needed) {
+		err = -EAGAIN;
+		goto errout;
+	}
+	return hints;
+
+errout:
+	objagg_hints_put(hints);
+	return ERR_PTR(err);
+}
+
+void mlxsw_sp_acl_erp_rehash_hints_put(void *hints_priv)
+{
+	struct objagg_hints *hints = hints_priv;
+
+	objagg_hints_put(hints);
+}
+
 int mlxsw_sp_acl_erp_region_init(struct mlxsw_sp_acl_atcam_region *aregion)
 {
 	struct mlxsw_sp_acl_erp_table *erp_table;