[PATCH v4 net] octeontx2-pf: reset HTB scheduler topology before freeing queues

[Ratheesh Kannoth <rkannoth@marvell.com>]

HTB offload programs NIX_AF_TLxX_TOPOLOGY on QoS-allocated scheduler
queues via otx2_qos_txschq_set_parent_topology(), but teardown freed
those queues without clearing TOPOLOGY.  The AF only restores PARENT and
SCHEDULE on free, so PRIO_ANCHOR/RR_PRIO settings can survive in the
shared scheduler pool and affect later allocations.

Add otx2_qos_reset_schq_topology() and otx2_qos_free_hw_schq() to zero
TL4 through TL2 TOPOLOGY before each schq is returned to the AF during
hierarchy teardown and cfg rollback.  Skip the aggregation level (TL1):
it is a per-tx-link queue shared by the PF, default Tx hierarchy and VFs,
and is not freed back to the AF by nix_txschq_free_one().

Fixes: 5e6808b4c68d ("octeontx2-pf: Add support for HTB offload")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>

---
v3 -> v4: Addressed AI review comments.
	https://lore.kernel.org/netdev/20260902172428.534936-1-horms@kernel.org/
v2 -> v3: Addressed AI review comments.
	https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260824072147.3524339-1-rkannoth@marvell.com?part=1
v1 -> v2: Addressed sashiko comments
        https://sashiko.dev/#/patchset/20260821072812.2890922-1-rkannoth%40marvell.com
---
 .../net/ethernet/marvell/octeontx2/nic/qos.c  | 60 +++++++++++++++++--
 1 file changed, 55 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/qos.c b/drivers/net/ethernet/marvell/octeontx2/nic/qos.c
index 69c0911e28e9..f160b1618efa 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/qos.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/qos.c
@@ -235,13 +235,63 @@ static int otx2_qos_txschq_set_parent_topology(struct otx2_nic *pfvf,
 	return rc;
 }
 
+static int otx2_qos_reset_schq_topology(struct otx2_nic *pfvf, u16 lvl,
+					u16 schq)
+{
+	struct mbox *mbox = &pfvf->mbox;
+	struct nix_txschq_config *cfg;
+	int rc;
+
+	if (lvl < NIX_TXSCH_LVL_TL4 || lvl >= NIX_TXSCH_LVL_TL1)
+		return 0;
+
+	mutex_lock(&mbox->lock);
+
+	cfg = otx2_mbox_alloc_msg_nix_txschq_cfg(mbox);
+	if (!cfg) {
+		mutex_unlock(&mbox->lock);
+		return -ENOMEM;
+	}
+
+	cfg->lvl = lvl;
+	cfg->num_regs = 1;
+
+	if (lvl == NIX_TXSCH_LVL_TL4)
+		cfg->reg[0] = NIX_AF_TL4X_TOPOLOGY(schq);
+	else if (lvl == NIX_TXSCH_LVL_TL3)
+		cfg->reg[0] = NIX_AF_TL3X_TOPOLOGY(schq);
+	else if (lvl == NIX_TXSCH_LVL_TL2)
+		cfg->reg[0] = NIX_AF_TL2X_TOPOLOGY(schq);
+
+	cfg->regval[0] = 0;
+
+	rc = otx2_sync_mbox_msg(mbox);
+
+	mutex_unlock(&mbox->lock);
+
+	return rc;
+}
+
+static void otx2_qos_free_hw_schq(struct otx2_nic *pfvf, u16 lvl, u16 schq)
+{
+	int err;
+
+	err = otx2_qos_reset_schq_topology(pfvf, lvl, schq);
+	if (err)
+		netdev_warn(pfvf->netdev,
+			    "QoS: failed to reset topology for schq %u at level %u: %d\n",
+			    schq, lvl, err);
+
+	otx2_txschq_free_one(pfvf, lvl, schq);
+}
+
 static void otx2_qos_free_hw_node_schq(struct otx2_nic *pfvf,
 				       struct otx2_qos_node *parent)
 {
 	struct otx2_qos_node *node;
 
 	list_for_each_entry_reverse(node, &parent->child_schq_list, list)
-		otx2_txschq_free_one(pfvf, node->level, node->schq);
+		otx2_qos_free_hw_schq(pfvf, node->level, node->schq);
 }
 
 static void otx2_qos_free_hw_node(struct otx2_nic *pfvf,
@@ -252,7 +302,7 @@ static void otx2_qos_free_hw_node(struct otx2_nic *pfvf,
 	list_for_each_entry_safe(node, tmp, &parent->child_list, list) {
 		otx2_qos_free_hw_node(pfvf, node);
 		otx2_qos_free_hw_node_schq(pfvf, node);
-		otx2_txschq_free_one(pfvf, node->level, node->schq);
+		otx2_qos_free_hw_schq(pfvf, node->level, node->schq);
 	}
 }
 
@@ -266,7 +316,7 @@ static void otx2_qos_free_hw_cfg(struct otx2_nic *pfvf,
 	otx2_qos_free_hw_node_schq(pfvf, node);
 
 	/* free node hw mappings */
-	otx2_txschq_free_one(pfvf, node->level, node->schq);
+	otx2_qos_free_hw_schq(pfvf, node->level, node->schq);
 
 	mutex_unlock(&pfvf->qos.qos_lock);
 }
@@ -913,7 +963,7 @@ static void otx2_qos_free_cfg(struct otx2_nic *pfvf, struct otx2_qos_cfg *cfg)
 	for (lvl = 0; lvl < NIX_TXSCH_LVL_CNT; lvl++) {
 		for (idx = 0; idx < cfg->schq[lvl]; idx++) {
 			schq = cfg->schq_list[lvl][idx];
-			otx2_txschq_free_one(pfvf, lvl, schq);
+			otx2_qos_free_hw_schq(pfvf, lvl, schq);
 		}
 	}
 
@@ -921,7 +971,7 @@ static void otx2_qos_free_cfg(struct otx2_nic *pfvf, struct otx2_qos_cfg *cfg)
 		for (idx = 0; idx < cfg->schq_contig[lvl]; idx++) {
 			if (cfg->schq_index_used[lvl][idx]) {
 				schq = cfg->schq_contig_list[lvl][idx];
-				otx2_txschq_free_one(pfvf, lvl, schq);
+				otx2_qos_free_hw_schq(pfvf, lvl, schq);
 			}
 		}
 	}
-- 
2.43.0