mlxsw: spectrum: Use guaranteed buffer size as pool size limit

There are two resources associated with shared buffer size:
cap_total_buffer_size, and cap_guaranteed_shared_buffer. So far, mlxsw has
been using the former as a limit to determine how large a pool size is
allowed to be. However, the total size also includes headrooms and reserved
space, which really cannot be used for shared buffer pools.

Therefore convert mlxsw to use the latter resource as a limit. Adjust
hard-coded pool sizes to be the guaranteed size minus 256000 bytes for CPU
port pool. On Spectrum-1 that actually leads to an increase. A follow-up
patch will have this size calculated automatically.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -26,7 +26,7 @@ enum mlxsw_res_id {
 	MLXSW_RES_ID_MAX_LAG_MEMBERS,
 	MLXSW_RES_ID_LOCAL_PORTS_IN_1X,
 	MLXSW_RES_ID_LOCAL_PORTS_IN_2X,
-	MLXSW_RES_ID_MAX_BUFFER_SIZE,
+	MLXSW_RES_ID_GUARANTEED_SHARED_BUFFER,
 	MLXSW_RES_ID_CELL_SIZE,
 	MLXSW_RES_ID_MAX_HEADROOM_SIZE,
 	MLXSW_RES_ID_ACL_MAX_TCAM_REGIONS,
@@ -82,7 +82,7 @@ static u16 mlxsw_res_ids[] = {
 	[MLXSW_RES_ID_MAX_LAG_MEMBERS] = 0x2521,
 	[MLXSW_RES_ID_LOCAL_PORTS_IN_1X] = 0x2610,
 	[MLXSW_RES_ID_LOCAL_PORTS_IN_2X] = 0x2611,
-	[MLXSW_RES_ID_MAX_BUFFER_SIZE] = 0x2802,	/* Bytes */
+	[MLXSW_RES_ID_GUARANTEED_SHARED_BUFFER] = 0x2805,	/* Bytes */
 	[MLXSW_RES_ID_CELL_SIZE] = 0x2803,	/* Bytes */
 	[MLXSW_RES_ID_MAX_HEADROOM_SIZE] = 0x2811,	/* Bytes */
 	[MLXSW_RES_ID_ACL_MAX_TCAM_REGIONS] = 0x2901,

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

@@ -421,8 +421,8 @@ static void mlxsw_sp_sb_ports_fini(struct mlxsw_sp *mlxsw_sp)
 		.freeze_size = _freeze_size,				\
 	}
 
-#define MLXSW_SP1_SB_PR_INGRESS_SIZE	12440000
-#define MLXSW_SP1_SB_PR_EGRESS_SIZE	13232000
+#define MLXSW_SP1_SB_PR_INGRESS_SIZE	13768608
+#define MLXSW_SP1_SB_PR_EGRESS_SIZE	13768608
 #define MLXSW_SP1_SB_PR_CPU_SIZE	(256 * 1000)
 
 /* Order according to mlxsw_sp1_sb_pool_dess */
@@ -445,8 +445,8 @@ static const struct mlxsw_sp_sb_pr mlxsw_sp1_sb_prs[] = {
 			   MLXSW_SP1_SB_PR_CPU_SIZE, true, false),
 };
 
-#define MLXSW_SP2_SB_PR_INGRESS_SIZE	35297568
-#define MLXSW_SP2_SB_PR_EGRESS_SIZE	35297568
+#define MLXSW_SP2_SB_PR_INGRESS_SIZE	34084800
+#define MLXSW_SP2_SB_PR_EGRESS_SIZE	34084800
 #define MLXSW_SP2_SB_PR_CPU_SIZE	(256 * 1000)
 
 /* Order according to mlxsw_sp2_sb_pool_dess */
@@ -904,7 +904,7 @@ int mlxsw_sp_buffers_init(struct mlxsw_sp *mlxsw_sp)
 	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, CELL_SIZE))
 		return -EIO;
 
-	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, MAX_BUFFER_SIZE))
+	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, GUARANTEED_SHARED_BUFFER))
 		return -EIO;
 
 	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, MAX_HEADROOM_SIZE))
@@ -915,7 +915,7 @@ int mlxsw_sp_buffers_init(struct mlxsw_sp *mlxsw_sp)
 		return -ENOMEM;
 	mlxsw_sp->sb->cell_size = MLXSW_CORE_RES_GET(mlxsw_sp->core, CELL_SIZE);
 	mlxsw_sp->sb->sb_size = MLXSW_CORE_RES_GET(mlxsw_sp->core,
-						   MAX_BUFFER_SIZE);
+						   GUARANTEED_SHARED_BUFFER);
 	max_headroom_size = MLXSW_CORE_RES_GET(mlxsw_sp->core,
 					       MAX_HEADROOM_SIZE);
 	/* Round down, because this limit must not be overstepped. */
@@ -1013,7 +1013,8 @@ int mlxsw_sp_sb_pool_set(struct mlxsw_core *mlxsw_core,
 	mode = (enum mlxsw_reg_sbpr_mode) threshold_type;
 	pr = &mlxsw_sp->sb_vals->prs[pool_index];
 
-	if (size > MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_BUFFER_SIZE)) {
+	if (size > MLXSW_CORE_RES_GET(mlxsw_sp->core,
+				      GUARANTEED_SHARED_BUFFER)) {
 		NL_SET_ERR_MSG_MOD(extack, "Exceeded shared buffer size");
 		return -EINVAL;
 	}

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

@@ -305,7 +305,8 @@ mlxsw_sp_qdisc_red_check_params(struct mlxsw_sp_port *mlxsw_sp_port,
 			p->max);
 		return -EINVAL;
 	}
-	if (p->max > MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_BUFFER_SIZE)) {
+	if (p->max > MLXSW_CORE_RES_GET(mlxsw_sp->core,
+					GUARANTEED_SHARED_BUFFER)) {
 		dev_err(mlxsw_sp->bus_info->dev,
 			"spectrum: RED: max value %u is too big\n", p->max);
 		return -EINVAL;