idpf: add TX splitq napi poll support

Add support to handle the interrupts for the TX completion queue and
process the various completion types.

In the flow scheduling mode, the driver processes primarily buffer
completions as well as descriptor completions occasionally. This mode
supports out of order TX completions. To do so, HW generates one buffer
completion per packet. Each of those completions contains the unique tag
provided during the TX encoding which is used to locate the packet either
on the TX buffer ring or in a hash table. The hash table is used to track
TX buffer information so the descriptor(s) for a given packet can be
reused while the driver is still waiting on the buffer completion(s).

Packets end up in the hash table in one of 2 ways: 1) a packet was
stashed during descriptor completion cleaning, or 2) because an out of
order buffer completion was processed. A descriptor completion arrives
only every so often and is primarily used to guarantee the TX descriptor
ring can be reused without having to wait on the individual buffer
completions. E.g. a descriptor completion for N+16 guarantees HW read all
of the descriptors for packets N through N+15, therefore all of the
buffers for packets N through N+15 are stashed into the hash table and the
descriptors can be reused for more TX packets. Similarly, a packet can be
stashed in the hash table because an out an order buffer completion was
processed. E.g. processing a buffer completion for packet N+3 implies that
HW read all of the descriptors for packets N through N+3 and they can be
reused. However, the HW did not do the DMA yet. The buffers for packets N
through N+2 cannot be freed, so they are stashed in the hash table.
In either case, the buffer completions will eventually be processed for
all of the stashed packets, and all of the buffers will be cleaned from
the hash table.

In queue based scheduling mode, the driver processes primarily descriptor
completions and cleans the TX ring the conventional way.

Finally, the driver triggers a TX queue drain after sending the disable
queues virtchnl message. When the HW completes the queue draining, it
sends the driver a queue marker packet completion. The driver determines
when all TX queues have been drained and proceeds with the disable flow.

With this, the driver can send TX packets and clean up the resources
properly.

Signed-off-by: Joshua Hay <joshua.a.hay@intel.com>
Co-developed-by: Alan Brady <alan.brady@intel.com>
Signed-off-by: Alan Brady <alan.brady@intel.com>
Co-developed-by: Madhu Chittim <madhu.chittim@intel.com>
Signed-off-by: Madhu Chittim <madhu.chittim@intel.com>
Co-developed-by: Phani Burra <phani.r.burra@intel.com>
Signed-off-by: Phani Burra <phani.r.burra@intel.com>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Co-developed-by: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
Signed-off-by: Pavan Kumar Linga <pavan.kumar.linga@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 51 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
index 3208a613305c..d1f549fe7d6b 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
@@ -646,6 +646,36 @@ static int idpf_wait_for_event(struct idpf_adapter *adapter,
 }
 
 /**
+ * idpf_wait_for_marker_event - wait for software marker response
+ * @vport: virtual port data structure
+ *
+ * Returns 0 success, negative on failure.
+ **/
+static int idpf_wait_for_marker_event(struct idpf_vport *vport)
+{
+	int event;
+	int i;
+
+	for (i = 0; i < vport->num_txq; i++)
+		set_bit(__IDPF_Q_SW_MARKER, vport->txqs[i]->flags);
+
+	event = wait_event_timeout(vport->sw_marker_wq,
+				   test_and_clear_bit(IDPF_VPORT_SW_MARKER,
+						      vport->flags),
+				   msecs_to_jiffies(500));
+
+	for (i = 0; i < vport->num_txq; i++)
+		clear_bit(__IDPF_Q_POLL_MODE, vport->txqs[i]->flags);
+
+	if (event)
+		return 0;
+
+	dev_warn(&vport->adapter->pdev->dev, "Failed to receive marker packets\n");
+
+	return -ETIMEDOUT;
+}
+
+/**
  * idpf_send_ver_msg - send virtchnl version message
  * @adapter: Driver specific private structure
  *
@@ -1936,7 +1966,23 @@ int idpf_send_enable_queues_msg(struct idpf_vport *vport)
  */
 int idpf_send_disable_queues_msg(struct idpf_vport *vport)
 {
-	return idpf_send_ena_dis_queues_msg(vport, VIRTCHNL2_OP_DISABLE_QUEUES);
+	int err, i;
+
+	err = idpf_send_ena_dis_queues_msg(vport, VIRTCHNL2_OP_DISABLE_QUEUES);
+	if (err)
+		return err;
+
+	/* switch to poll mode as interrupts will be disabled after disable
+	 * queues virtchnl message is sent
+	 */
+	for (i = 0; i < vport->num_txq; i++)
+		set_bit(__IDPF_Q_POLL_MODE, vport->txqs[i]->flags);
+
+	/* schedule the napi to receive all the marker packets */
+	for (i = 0; i < vport->num_q_vectors; i++)
+		napi_schedule(&vport->q_vectors[i].napi);
+
+	return idpf_wait_for_marker_event(vport);
 }
 
 /**
@@ -2813,6 +2859,7 @@ void idpf_vport_init(struct idpf_vport *vport, struct idpf_vport_max_q *max_q)
 	struct idpf_adapter *adapter = vport->adapter;
 	struct virtchnl2_create_vport *vport_msg;
 	struct idpf_vport_config *vport_config;
+	u16 tx_itr[] = {2, 8, 64, 128, 256};
 	struct idpf_rss_data *rss_data;
 	u16 idx = vport->idx;
 
@@ -2837,6 +2884,9 @@ void idpf_vport_init(struct idpf_vport *vport, struct idpf_vport_max_q *max_q)
 	ether_addr_copy(vport->default_mac_addr, vport_msg->default_mac_addr);
 	vport->max_mtu = le16_to_cpu(vport_msg->max_mtu) - IDPF_PACKET_HDR_PAD;
 
+	/* Initialize Tx profiles for Dynamic Interrupt Moderation */
+	memcpy(vport->tx_itr_profile, tx_itr, IDPF_DIM_PROFILE_SLOTS);
+
 	idpf_vport_init_num_qs(vport, vport_msg);
 	idpf_vport_calc_num_q_desc(vport);
 	idpf_vport_calc_num_q_groups(vport);