Subject: Re: [PATCH net-next 2/2] mlxsw: spectrum_buffers: Add the ability to query the CPU port's shared buffer

From: Jiri Pirko <[email-masked]>
Date: Fri, 13 Sep 2019 10:17:36 +0200

Thu, Sep 12, 2019 at 03:07:40PM CEST, [email-masked] wrote:
>From: Shalom Toledo <[email-masked]>
>
>While debugging packet loss towards the CPU, it is useful to be able to
>query the CPU port's shared buffer quotas and occupancy.
>
>Since the CPU port has no ingress buffers, all the shared buffers ingress
>information will be cleared.
>
>Signed-off-by: Shalom Toledo <[email-masked]>
>Signed-off-by: Ido Schimmel <[email-masked]>
>---
> .../mellanox/mlxsw/spectrum_buffers.c         | 51 ++++++++++++++++---
> 1 file changed, 43 insertions(+), 8 deletions(-)
>
>diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
>index 888ba4300bcc..b9eeae37a4dc 100644
>--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
>+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
>@@ -250,6 +250,10 @@ static int mlxsw_sp_sb_pm_occ_clear(struct mlxsw_sp *mlxsw_sp, u8 local_port,
> 		&mlxsw_sp->sb_vals->pool_dess[pool_index];
> 	char sbpm_pl[MLXSW_REG_SBPM_LEN];
> 
>+	if (local_port == MLXSW_PORT_CPU_PORT &&
>+	    des->dir == MLXSW_REG_SBXX_DIR_INGRESS)
>+		return 0;
>+
> 	mlxsw_reg_sbpm_pack(sbpm_pl, local_port, des->pool, des->dir,
> 			    true, 0, 0);
> 	return mlxsw_reg_trans_query(mlxsw_sp->core, MLXSW_REG(sbpm), sbpm_pl,
>@@ -273,6 +277,10 @@ static int mlxsw_sp_sb_pm_occ_query(struct mlxsw_sp *mlxsw_sp, u8 local_port,
> 	char sbpm_pl[MLXSW_REG_SBPM_LEN];
> 	struct mlxsw_sp_sb_pm *pm;
> 
>+	if (local_port == MLXSW_PORT_CPU_PORT &&
>+	    des->dir == MLXSW_REG_SBXX_DIR_INGRESS)
>+		return 0;
>+
> 	pm = mlxsw_sp_sb_pm_get(mlxsw_sp, local_port, pool_index);
> 	mlxsw_reg_sbpm_pack(sbpm_pl, local_port, des->pool, des->dir,
> 			    false, 0, 0);
>@@ -1085,6 +1093,11 @@ int mlxsw_sp_sb_port_pool_set(struct mlxsw_core_port *mlxsw_core_port,
> 	u32 max_buff;
> 	int err;
> 
>+	if (local_port == MLXSW_PORT_CPU_PORT) {
>+		NL_SET_ERR_MSG_MOD(extack, "Changing CPU port's threshold is forbidden");
>+		return -EINVAL;
>+	}
>+
> 	err = mlxsw_sp_sb_threshold_in(mlxsw_sp, pool_index,
> 				       threshold, &max_buff, extack);
> 	if (err)
>@@ -1130,6 +1143,11 @@ int mlxsw_sp_sb_tc_pool_bind_set(struct mlxsw_core_port *mlxsw_core_port,
> 	u32 max_buff;
> 	int err;
> 
>+	if (local_port == MLXSW_PORT_CPU_PORT) {
>+		NL_SET_ERR_MSG_MOD(extack, "Changing CPU port's binding is forbidden");

I believe you need to add this check before the previous patch that
introduces the cpu port.

>+		return -EINVAL;
>+	}
>+
> 	if (dir != mlxsw_sp->sb_vals->pool_dess[pool_index].dir) {
> 		NL_SET_ERR_MSG_MOD(extack, "Binding egress TC to ingress pool and vice versa is forbidden");
> 		return -EINVAL;
>@@ -1187,6 +1205,11 @@ static void mlxsw_sp_sb_sr_occ_query_cb(struct mlxsw_core *mlxsw_core,
> 	     local_port < mlxsw_core_max_ports(mlxsw_core); local_port++) {
> 		if (!mlxsw_sp->ports[local_port])
> 			continue;
>+		if (local_port == MLXSW_PORT_CPU_PORT) {
>+			/* Ingress quotas are not supported for the CPU port */
>+			masked_count++;
>+			continue;
>+		}
> 		for (i = 0; i < MLXSW_SP_SB_ING_TC_COUNT; i++) {
> 			cm = mlxsw_sp_sb_cm_get(mlxsw_sp, local_port, i,
> 						MLXSW_REG_SBXX_DIR_INGRESS);
>@@ -1222,7 +1245,7 @@ int mlxsw_sp_sb_occ_snapshot(struct mlxsw_core *mlxsw_core,
> 	char *sbsr_pl;
> 	u8 masked_count;
> 	u8 local_port_1;
>-	u8 local_port = 0;
>+	u8 local_port;
> 	int i;
> 	int err;
> 	int err2;
>@@ -1231,8 +1254,8 @@ int mlxsw_sp_sb_occ_snapshot(struct mlxsw_core *mlxsw_core,
> 	if (!sbsr_pl)
> 		return -ENOMEM;
> 
>+	local_port = MLXSW_PORT_CPU_PORT;
> next_batch:
>-	local_port++;
> 	local_port_1 = local_port;
> 	masked_count = 0;
> 	mlxsw_reg_sbsr_pack(sbsr_pl, false);
>@@ -1243,7 +1266,11 @@ int mlxsw_sp_sb_occ_snapshot(struct mlxsw_core *mlxsw_core,
> 	for (; local_port < mlxsw_core_max_ports(mlxsw_core); local_port++) {
> 		if (!mlxsw_sp->ports[local_port])
> 			continue;
>-		mlxsw_reg_sbsr_ingress_port_mask_set(sbsr_pl, local_port, 1);
>+		if (local_port != MLXSW_PORT_CPU_PORT) {
>+			/* Ingress quotas are not supported for the CPU port */
>+			mlxsw_reg_sbsr_ingress_port_mask_set(sbsr_pl,
>+							     local_port, 1);
>+		}
> 		mlxsw_reg_sbsr_egress_port_mask_set(sbsr_pl, local_port, 1);
> 		for (i = 0; i < mlxsw_sp->sb_vals->pool_count; i++) {
> 			err = mlxsw_sp_sb_pm_occ_query(mlxsw_sp, local_port, i,
>@@ -1264,8 +1291,10 @@ int mlxsw_sp_sb_occ_snapshot(struct mlxsw_core *mlxsw_core,
> 				    cb_priv);
> 	if (err)
> 		goto out;
>-	if (local_port < mlxsw_core_max_ports(mlxsw_core))
>+	if (local_port < mlxsw_core_max_ports(mlxsw_core)) {
>+		local_port++;
> 		goto next_batch;
>+	}
> 
> out:
> 	err2 = mlxsw_reg_trans_bulk_wait(&bulk_list);
>@@ -1282,7 +1311,7 @@ int mlxsw_sp_sb_occ_max_clear(struct mlxsw_core *mlxsw_core,
> 	LIST_HEAD(bulk_list);
> 	char *sbsr_pl;
> 	unsigned int masked_count;
>-	u8 local_port = 0;
>+	u8 local_port;
> 	int i;
> 	int err;
> 	int err2;
>@@ -1291,8 +1320,8 @@ int mlxsw_sp_sb_occ_max_clear(struct mlxsw_core *mlxsw_core,
> 	if (!sbsr_pl)
> 		return -ENOMEM;
> 
>+	local_port = MLXSW_PORT_CPU_PORT;
> next_batch:
>-	local_port++;
> 	masked_count = 0;
> 	mlxsw_reg_sbsr_pack(sbsr_pl, true);
> 	for (i = 0; i < MLXSW_SP_SB_ING_TC_COUNT; i++)
>@@ -1302,7 +1331,11 @@ int mlxsw_sp_sb_occ_max_clear(struct mlxsw_core *mlxsw_core,
> 	for (; local_port < mlxsw_core_max_ports(mlxsw_core); local_port++) {
> 		if (!mlxsw_sp->ports[local_port])
> 			continue;
>-		mlxsw_reg_sbsr_ingress_port_mask_set(sbsr_pl, local_port, 1);
>+		if (local_port != MLXSW_PORT_CPU_PORT) {
>+			/* Ingress quotas are not supported for the CPU port */
>+			mlxsw_reg_sbsr_ingress_port_mask_set(sbsr_pl,
>+							     local_port, 1);
>+		}
> 		mlxsw_reg_sbsr_egress_port_mask_set(sbsr_pl, local_port, 1);
> 		for (i = 0; i < mlxsw_sp->sb_vals->pool_count; i++) {
> 			err = mlxsw_sp_sb_pm_occ_clear(mlxsw_sp, local_port, i,
>@@ -1319,8 +1352,10 @@ int mlxsw_sp_sb_occ_max_clear(struct mlxsw_core *mlxsw_core,
> 				    &bulk_list, NULL, 0);
> 	if (err)
> 		goto out;
>-	if (local_port < mlxsw_core_max_ports(mlxsw_core))
>+	if (local_port < mlxsw_core_max_ports(mlxsw_core)) {
>+		local_port++;
> 		goto next_batch;
>+	}
> 
> out:
> 	err2 = mlxsw_reg_trans_bulk_wait(&bulk_list);
>-- 
>2.21.0
>