net: dsa: sja1105: implement a common frame memory partitioning function

There are 2 different features that require some reserved frame memory
space: VLAN retagging and virtual links. Create a central function that
modifies the static config and ensures frame memory is never
overcommitted.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/sja1105/sja1105.h

@@ -244,6 +244,8 @@ enum sja1105_reset_reason {
 int sja1105_static_config_reload(struct sja1105_private *priv,
 				 enum sja1105_reset_reason reason);
 
+void sja1105_frame_memory_partitioning(struct sja1105_private *priv);
+
 /* From sja1105_spi.c */
 int sja1105_xfer_buf(const struct sja1105_private *priv,
 		     sja1105_spi_rw_mode_t rw, u64 reg_addr,

drivers/net/dsa/sja1105/sja1105_main.c

@@ -432,6 +432,41 @@ static int sja1105_init_l2_forwarding_params(struct sja1105_private *priv)
 	return 0;
 }
 
+void sja1105_frame_memory_partitioning(struct sja1105_private *priv)
+{
+	struct sja1105_l2_forwarding_params_entry *l2_fwd_params;
+	struct sja1105_vl_forwarding_params_entry *vl_fwd_params;
+	struct sja1105_table *table;
+	int max_mem;
+
+	/* VLAN retagging is implemented using a loopback port that consumes
+	 * frame buffers. That leaves less for us.
+	 */
+	if (priv->vlan_state == SJA1105_VLAN_BEST_EFFORT)
+		max_mem = SJA1105_MAX_FRAME_MEMORY_RETAGGING;
+	else
+		max_mem = SJA1105_MAX_FRAME_MEMORY;
+
+	table = &priv->static_config.tables[BLK_IDX_L2_FORWARDING_PARAMS];
+	l2_fwd_params = table->entries;
+	l2_fwd_params->part_spc[0] = max_mem;
+
+	/* If we have any critical-traffic virtual links, we need to reserve
+	 * some frame buffer memory for them. At the moment, hardcode the value
+	 * at 100 blocks of 128 bytes of memory each. This leaves 829 blocks
+	 * remaining for best-effort traffic. TODO: figure out a more flexible
+	 * way to perform the frame buffer partitioning.
+	 */
+	if (!priv->static_config.tables[BLK_IDX_VL_FORWARDING].entry_count)
+		return;
+
+	table = &priv->static_config.tables[BLK_IDX_VL_FORWARDING_PARAMS];
+	vl_fwd_params = table->entries;
+
+	l2_fwd_params->part_spc[0] -= SJA1105_VL_FRAME_MEMORY;
+	vl_fwd_params->partspc[0] = SJA1105_VL_FRAME_MEMORY;
+}
+
 static int sja1105_init_general_params(struct sja1105_private *priv)
 {
 	struct sja1105_general_params_entry default_general_params = {
@@ -2213,6 +2248,8 @@ static int sja1105_vlan_filtering(struct dsa_switch *ds, int port, bool enabled)
 	l2_lookup_params = table->entries;
 	l2_lookup_params->shared_learn = want_tagging;
 
+	sja1105_frame_memory_partitioning(priv);
+
 	rc = sja1105_static_config_reload(priv, SJA1105_VLAN_FILTERING);
 	if (rc)
 		dev_err(ds->dev, "Failed to change VLAN Ethertype\n");

drivers/net/dsa/sja1105/sja1105_static_config.h

@@ -108,6 +108,7 @@ enum sja1105_blk_idx {
 
 #define SJA1105_MAX_FRAME_MEMORY			929
 #define SJA1105_MAX_FRAME_MEMORY_RETAGGING		910
+#define SJA1105_VL_FRAME_MEMORY				100
 
 #define SJA1105E_DEVICE_ID				0x9C00000Cull
 #define SJA1105T_DEVICE_ID				0x9E00030Eull

drivers/net/dsa/sja1105/sja1105_vl.c

@@ -5,7 +5,6 @@
 #include <linux/dsa/8021q.h>
 #include "sja1105.h"
 
-#define SJA1105_VL_FRAME_MEMORY			100
 #define SJA1105_SIZE_VL_STATUS			8
 
 /* The switch flow classification core implements TTEthernet, which 'thinks' in
@@ -141,8 +140,6 @@ static bool sja1105_vl_key_lower(struct sja1105_vl_lookup_entry *a,
 static int sja1105_init_virtual_links(struct sja1105_private *priv,
 				      struct netlink_ext_ack *extack)
 {
-	struct sja1105_l2_forwarding_params_entry *l2_fwd_params;
-	struct sja1105_vl_forwarding_params_entry *vl_fwd_params;
 	struct sja1105_vl_policing_entry *vl_policing;
 	struct sja1105_vl_forwarding_entry *vl_fwd;
 	struct sja1105_vl_lookup_entry *vl_lookup;
@@ -153,10 +150,6 @@ static int sja1105_init_virtual_links(struct sja1105_private *priv,
 	int max_sharindx = 0;
 	int i, j, k;
 
-	table = &priv->static_config.tables[BLK_IDX_L2_FORWARDING_PARAMS];
-	l2_fwd_params = table->entries;
-	l2_fwd_params->part_spc[0] = SJA1105_MAX_FRAME_MEMORY;
-
 	/* Figure out the dimensioning of the problem */
 	list_for_each_entry(rule, &priv->flow_block.rules, list) {
 		if (rule->type != SJA1105_RULE_VL)
@@ -308,17 +301,6 @@ static int sja1105_init_virtual_links(struct sja1105_private *priv,
 	if (!table->entries)
 		return -ENOMEM;
 	table->entry_count = 1;
-	vl_fwd_params = table->entries;
-
-	/* Reserve some frame buffer memory for the critical-traffic virtual
-	 * links (this needs to be done). At the moment, hardcode the value
-	 * at 100 blocks of 128 bytes of memory each. This leaves 829 blocks
-	 * remaining for best-effort traffic. TODO: figure out a more flexible
-	 * way to perform the frame buffer partitioning.
-	 */
-	l2_fwd_params->part_spc[0] = SJA1105_MAX_FRAME_MEMORY -
-				     SJA1105_VL_FRAME_MEMORY;
-	vl_fwd_params->partspc[0] = SJA1105_VL_FRAME_MEMORY;
 
 	for (i = 0; i < num_virtual_links; i++) {
 		unsigned long cookie = vl_lookup[i].flow_cookie;
@@ -342,6 +324,8 @@ static int sja1105_init_virtual_links(struct sja1105_private *priv,
 		}
 	}
 
+	sja1105_frame_memory_partitioning(priv);
+
 	return 0;
 }