[PATCH v3 06/16] net/ice/base: allow init without TC class sched nodes

[Bruce Richardson <bruce.richardson@intel.com>]

If DCB support is disabled via DDP image, there will not be any traffic
class (TC) nodes in the scheduler tree immediately above the root level.
To allow the driver to work with this scenario, we allow use of the root
node as a dummy TC0 node in case where there are no TC nodes in the
tree. For use of any other TC other than 0 (used by default in the
driver), existing behaviour of returning NULL pointer is maintained.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 drivers/net/ice/base/ice_sched.c | 6 ++++++
 drivers/net/ice/base/ice_type.h  | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/net/ice/base/ice_sched.c b/drivers/net/ice/base/ice_sched.c
index 373c32a518..f75e5ae599 100644
--- a/drivers/net/ice/base/ice_sched.c
+++ b/drivers/net/ice/base/ice_sched.c
@@ -292,6 +292,10 @@ struct ice_sched_node *ice_sched_get_tc_node(struct ice_port_info *pi, u8 tc)
 
 	if (!pi || !pi->root)
 		return NULL;
+	/* if no TC nodes, use root as TC node 0 */
+	if (pi->has_tc == 0)
+		return tc == 0 ? pi->root : NULL;
+
 	for (i = 0; i < pi->root->num_children; i++)
 		if (pi->root->children[i]->tc_num == tc)
 			return pi->root->children[i];
@@ -1306,6 +1310,8 @@ int ice_sched_init_port(struct ice_port_info *pi)
 			    ICE_AQC_ELEM_TYPE_ENTRY_POINT)
 				hw->sw_entry_point_layer = j;
 
+			if (buf[0].generic[j].data.elem_type == ICE_AQC_ELEM_TYPE_TC)
+				pi->has_tc = 1;
 			status = ice_sched_add_node(pi, j, &buf[i].generic[j], NULL);
 			if (status)
 				goto err_init_port;
diff --git a/drivers/net/ice/base/ice_type.h b/drivers/net/ice/base/ice_type.h
index 598a80155b..a70e4a8afa 100644
--- a/drivers/net/ice/base/ice_type.h
+++ b/drivers/net/ice/base/ice_type.h
@@ -1260,6 +1260,7 @@ struct ice_port_info {
 	struct ice_qos_cfg qos_cfg;
 	u8 is_vf:1;
 	u8 is_custom_tx_enabled:1;
+	u8 has_tc:1;
 };
 
 struct ice_switch_info {
-- 
2.43.0