[PATCH net-next v3 3/4] net: dsa: motorcomm: Enable ACL on demand

[David Yang <mmyangfl@gmail.com>]

Track the usage of ACL rules and enable it per port only when it is
actually used. This is aligned with ODM recommendations and helps reduce
latency.

Signed-off-by: David Yang <mmyangfl@gmail.com>
---
 drivers/net/dsa/motorcomm/chip.h |  2 +
 drivers/net/dsa/motorcomm/tc.c   | 70 ++++++++++++++++++++++++++++----
 2 files changed, 64 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/motorcomm/chip.h b/drivers/net/dsa/motorcomm/chip.h
index 012de4f444f5..7047ad98f431 100644
--- a/drivers/net/dsa/motorcomm/chip.h
+++ b/drivers/net/dsa/motorcomm/chip.h
@@ -462,6 +462,8 @@ struct yt921x_port {
 	/* BR_ISOLATED */
 	bool isolated:1;
 
+	unsigned short acl_cnt;
+
 #if IS_ENABLED(CONFIG_NET_DSA_YT921X_LEDS)
 	unsigned char led_duty;
 	unsigned short led_cycle;
diff --git a/drivers/net/dsa/motorcomm/tc.c b/drivers/net/dsa/motorcomm/tc.c
index be3321df8868..a302016912b5 100644
--- a/drivers/net/dsa/motorcomm/tc.c
+++ b/drivers/net/dsa/motorcomm/tc.c
@@ -1055,6 +1055,19 @@ yt921x_acl_rule_ext_parse_flow(struct yt921x_acl_rule_ext *ruleext, int port,
 	return 0;
 }
 
+/* Ports that _should_ have ACL activated on. ACL_PORT \succeq activated_ports()
+ */
+static u16 yt921x_acl_activated_ports(const struct yt921x_priv *priv)
+{
+	u16 mask = 0;
+
+	for (int port = 0; port < YT921X_PORT_NUM; port++)
+		if (priv->ports[port].acl_cnt)
+			mask |= BIT(port);
+
+	return mask;
+}
+
 static unsigned int
 yt921x_acl_find(const struct yt921x_priv *priv, enum tc_setup_type type,
 		unsigned long tag)
@@ -1199,10 +1212,15 @@ yt921x_acl_del(struct yt921x_priv *priv, enum tc_setup_type type,
 {
 	struct yt921x_acl_rule *aclrule;
 	struct yt921x_acl_blk *aclblk;
+	bool refresh_en = false;
 	unsigned int binid;
 	unsigned int blkid;
 	unsigned int entid;
+	unsigned long m;
+	unsigned int o;
+	u32 ctrl;
 	int res;
+	int ret;
 
 	entid = yt921x_acl_find(priv, type, tag);
 	if (entid == UINT_MAX)
@@ -1214,9 +1232,27 @@ yt921x_acl_del(struct yt921x_priv *priv, enum tc_setup_type type,
 	aclrule = aclblk->rules[binid];
 
 	aclblk->rules[binid] = NULL;
-	res = yt921x_acl_commit(priv, entid, aclrule->mask);
+	ret = yt921x_acl_commit(priv, entid, aclrule->mask);
 	/* the kernel never rolls back on failure */
 
+	m = FIELD_GET(YT921X_ACL_KEYb_SPORTS_M, aclrule->entries[0].key[1]);
+	for_each_set_bit(o, &m, YT921X_PORT_NUM) {
+		struct yt921x_port *pp = &priv->ports[o];
+
+		if (!WARN_ON(!pp->acl_cnt)) {
+			pp->acl_cnt--;
+			if (pp->acl_cnt)
+				continue;
+		}
+		refresh_en = true;
+	}
+	if (refresh_en) {
+		ctrl = yt921x_acl_activated_ports(priv);
+		res = yt921x_reg_write(priv, YT921X_ACL_PORT, ctrl);
+		if (res)
+			ret = res;
+	}
+
 	if (aclrule->action[0] & YT921X_ACL_ACTa_METER_EN)
 		clear_bit(FIELD_GET(YT921X_ACL_ACTa_METER_ID_M,
 				    aclrule->action[0]),
@@ -1227,7 +1263,7 @@ yt921x_acl_del(struct yt921x_priv *priv, enum tc_setup_type type,
 		kvfree(aclblk);
 		priv->acl_blks[blkid] = NULL;
 	}
-	return res;
+	return ret;
 }
 
 static int
@@ -1240,11 +1276,12 @@ yt921x_acl_add(struct yt921x_priv *priv,
 	struct yt921x_acl_blk *aclblk;
 	bool use_trap = false;
 	unsigned int meterid;
-	unsigned long mask;
 	unsigned int binid;
 	unsigned int blkid;
 	unsigned int entid;
+	unsigned long m;
 	unsigned int o;
+	u32 ctrl;
 	int res;
 
 	/* Allocate resources */
@@ -1293,8 +1330,8 @@ yt921x_acl_add(struct yt921x_priv *priv,
 
 	/* Replace the placeholder resource IDs */
 	aclrule->mask = 0;
-	mask = priv->acl_masks[blkid];
-	for_each_clear_bit(o, &mask, YT921X_ACL_ENT_PER_BLK) {
+	m = priv->acl_masks[blkid];
+	for_each_clear_bit(o, &m, YT921X_ACL_ENT_PER_BLK) {
 		aclrule->mask |= BIT(o);
 		entscnt--;
 		if (!entscnt)
@@ -1312,21 +1349,39 @@ yt921x_acl_add(struct yt921x_priv *priv,
 	else
 		aclrule->action[0] &= ~YT921X_ACL_ACTa_METER_EN;
 
+	/* Activate ACL if needed */
+	ctrl = 0;
+	m = FIELD_GET(YT921X_ACL_KEYb_SPORTS_M, ruleext->r.entries[0].key[1]);
+	for_each_set_bit(o, &m, YT921X_PORT_NUM)
+		if (!priv->ports[o].acl_cnt)
+			ctrl |= YT921X_ACL_PORT_PORTn(o);
+	if (ctrl) {
+		ctrl |= yt921x_acl_activated_ports(priv);
+		res = yt921x_reg_write(priv, YT921X_ACL_PORT, ctrl);
+		if (res)
+			goto err;
+	}
+
 	/* Write rules */
 	aclblk->rules[binid] = aclrule;
 	res = yt921x_acl_commit(priv, entid, aclrule->mask);
 	if (res) {
 		aclblk->rules[binid] = NULL;
-		kvfree(aclrule);
 		goto err;
 	}
 
+	/* Bookkeeping */
+	m = FIELD_GET(YT921X_ACL_KEYb_SPORTS_M, ruleext->r.entries[0].key[1]);
+	for_each_set_bit(o, &m, YT921X_PORT_NUM)
+		priv->ports[o].acl_cnt++;
+
 	if (meterid < YT921X_METER_NUM)
 		set_bit(meterid, priv->meters_map);
 	priv->acl_masks[blkid] |= aclrule->mask;
 	return 0;
 
 err:
+	kvfree(aclrule);
 	if (!priv->acl_masks[blkid]) {
 		kvfree(aclblk);
 		priv->acl_blks[blkid] = NULL;
@@ -1487,8 +1542,7 @@ int yt921x_chip_setup_acl(struct yt921x_priv *priv)
 	if (res)
 		return res;
 
-	ctrl = YT921X_ACL_PORT_PORTS_M;
-	res = yt921x_reg_write(priv, YT921X_ACL_PORT, ctrl);
+	res = yt921x_reg_write(priv, YT921X_ACL_PORT, 0);
 	if (res)
 		return res;
 
-- 
2.53.0