mlxsw: spectrum: Allocate LAG table when in SW LAG mode

In this patch, if the LAG mode is SW, allocate the LAG table and configure
SGCR to indicate where it was allocated.

We use the default "DDD" (for dynamic data duplication) layout of the LAG
table. In the DDD mode, the membership information for each LAG is copied
in 8 PGT entries. This is done for performance reasons. The LAG table then
needs to be allocated on an address aligned to 8. Deal with this by
moving the LAG init ahead so that the LAG table is allocated at address 0.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

@@ -2692,6 +2692,63 @@ static void mlxsw_sp_traps_fini(struct mlxsw_sp *mlxsw_sp)
 	kfree(mlxsw_sp->trap);
 }
 
+static int mlxsw_sp_lag_pgt_init(struct mlxsw_sp *mlxsw_sp)
+{
+	char sgcr_pl[MLXSW_REG_SGCR_LEN];
+	u16 max_lag;
+	int err;
+
+	if (mlxsw_core_lag_mode(mlxsw_sp->core) !=
+	    MLXSW_CMD_MBOX_CONFIG_PROFILE_LAG_MODE_SW)
+		return 0;
+
+	err = mlxsw_core_max_lag(mlxsw_sp->core, &max_lag);
+	if (err)
+		return err;
+
+	/* In DDD mode, which we by default use, each LAG entry is 8 PGT
+	 * entries. The LAG table address needs to be 8-aligned, but that ought
+	 * to be the case, since the LAG table is allocated first.
+	 */
+	err = mlxsw_sp_pgt_mid_alloc_range(mlxsw_sp, &mlxsw_sp->lag_pgt_base,
+					   max_lag * 8);
+	if (err)
+		return err;
+	if (WARN_ON_ONCE(mlxsw_sp->lag_pgt_base % 8)) {
+		err = -EINVAL;
+		goto err_mid_alloc_range;
+	}
+
+	mlxsw_reg_sgcr_pack(sgcr_pl, mlxsw_sp->lag_pgt_base);
+	err = mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(sgcr), sgcr_pl);
+	if (err)
+		goto err_mid_alloc_range;
+
+	return 0;
+
+err_mid_alloc_range:
+	mlxsw_sp_pgt_mid_free_range(mlxsw_sp, mlxsw_sp->lag_pgt_base,
+				    max_lag * 8);
+	return err;
+}
+
+static void mlxsw_sp_lag_pgt_fini(struct mlxsw_sp *mlxsw_sp)
+{
+	u16 max_lag;
+	int err;
+
+	if (mlxsw_core_lag_mode(mlxsw_sp->core) !=
+	    MLXSW_CMD_MBOX_CONFIG_PROFILE_LAG_MODE_SW)
+		return;
+
+	err = mlxsw_core_max_lag(mlxsw_sp->core, &max_lag);
+	if (err)
+		return;
+
+	mlxsw_sp_pgt_mid_free_range(mlxsw_sp, mlxsw_sp->lag_pgt_base,
+				    max_lag * 8);
+}
+
 #define MLXSW_SP_LAG_SEED_INIT 0xcafecafe
 
 static int mlxsw_sp_lag_init(struct mlxsw_sp *mlxsw_sp)
@@ -2723,16 +2780,27 @@ static int mlxsw_sp_lag_init(struct mlxsw_sp *mlxsw_sp)
 	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, MAX_LAG_MEMBERS))
 		return -EIO;
 
+	err = mlxsw_sp_lag_pgt_init(mlxsw_sp);
+	if (err)
+		return err;
+
 	mlxsw_sp->lags = kcalloc(max_lag, sizeof(struct mlxsw_sp_upper),
 				 GFP_KERNEL);
-	if (!mlxsw_sp->lags)
-		return -ENOMEM;
+	if (!mlxsw_sp->lags) {
+		err = -ENOMEM;
+		goto err_kcalloc;
+	}
 
 	return 0;
+
+err_kcalloc:
+	mlxsw_sp_lag_pgt_fini(mlxsw_sp);
+	return err;
 }
 
 static void mlxsw_sp_lag_fini(struct mlxsw_sp *mlxsw_sp)
 {
+	mlxsw_sp_lag_pgt_fini(mlxsw_sp);
 	kfree(mlxsw_sp->lags);
 }
 
@@ -3113,6 +3181,15 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 		goto err_pgt_init;
 	}
 
+	/* Initialize before FIDs so that the LAG table is at the start of PGT
+	 * and 8-aligned without overallocation.
+	 */
+	err = mlxsw_sp_lag_init(mlxsw_sp);
+	if (err) {
+		dev_err(mlxsw_sp->bus_info->dev, "Failed to initialize LAG\n");
+		goto err_lag_init;
+	}
+
 	err = mlxsw_sp_fids_init(mlxsw_sp);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to initialize FIDs\n");
@@ -3143,12 +3220,6 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 		goto err_buffers_init;
 	}
 
-	err = mlxsw_sp_lag_init(mlxsw_sp);
-	if (err) {
-		dev_err(mlxsw_sp->bus_info->dev, "Failed to initialize LAG\n");
-		goto err_lag_init;
-	}
-
 	/* Initialize SPAN before router and switchdev, so that those components
 	 * can call mlxsw_sp_span_respin().
 	 */
@@ -3300,8 +3371,6 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 err_switchdev_init:
 	mlxsw_sp_span_fini(mlxsw_sp);
 err_span_init:
-	mlxsw_sp_lag_fini(mlxsw_sp);
-err_lag_init:
 	mlxsw_sp_buffers_fini(mlxsw_sp);
 err_buffers_init:
 	mlxsw_sp_devlink_traps_fini(mlxsw_sp);
@@ -3312,6 +3381,8 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 err_policers_init:
 	mlxsw_sp_fids_fini(mlxsw_sp);
 err_fids_init:
+	mlxsw_sp_lag_fini(mlxsw_sp);
+err_lag_init:
 	mlxsw_sp_pgt_fini(mlxsw_sp);
 err_pgt_init:
 	mlxsw_sp_kvdl_fini(mlxsw_sp);
@@ -3477,12 +3548,12 @@ static void mlxsw_sp_fini(struct mlxsw_core *mlxsw_core)
 	mlxsw_sp_counter_pool_fini(mlxsw_sp);
 	mlxsw_sp_switchdev_fini(mlxsw_sp);
 	mlxsw_sp_span_fini(mlxsw_sp);
-	mlxsw_sp_lag_fini(mlxsw_sp);
 	mlxsw_sp_buffers_fini(mlxsw_sp);
 	mlxsw_sp_devlink_traps_fini(mlxsw_sp);
 	mlxsw_sp_traps_fini(mlxsw_sp);
 	mlxsw_sp_policers_fini(mlxsw_sp);
 	mlxsw_sp_fids_fini(mlxsw_sp);
+	mlxsw_sp_lag_fini(mlxsw_sp);
 	mlxsw_sp_pgt_fini(mlxsw_sp);
 	mlxsw_sp_kvdl_fini(mlxsw_sp);
 	mlxsw_sp_parsing_fini(mlxsw_sp);

drivers/net/ethernet/mellanox/mlxsw/spectrum.h

@@ -212,6 +212,7 @@ struct mlxsw_sp {
 	struct mutex ipv6_addr_ht_lock; /* Protects ipv6_addr_ht */
 	struct mlxsw_sp_pgt *pgt;
 	bool pgt_smpe_index_valid;
+	u16 lag_pgt_base;
 };
 
 struct mlxsw_sp_ptp_ops {