igc: Fix TX Hang issue when QBV Gate is closed

If a user schedules a Gate Control List (GCL) to close one of
the QBV gates while also transmitting a packet to that closed gate,
TX Hang will be happen. HW would not drop any packet when the gate
is closed and keep queuing up in HW TX FIFO until the gate is re-opened.
This patch implements the solution to drop the packet for the closed
gate.

This patch will also reset the adapter to perform SW initialization
for each 1st Gate Control List (GCL) to avoid hang.
This is due to the HW design, where changing to TSN transmit mode
requires SW initialization. Intel Discrete I225/6 transmit mode
cannot be changed when in dynamic mode according to Software User
Manual Section 7.5.2.1. Subsequent Gate Control List (GCL) operations
will proceed without a reset, as they already are in TSN Mode.

Step to reproduce:

DUT:
1) Configure GCL List with certain gate close.

BASE=$(date +%s%N)
tc qdisc replace dev $IFACE parent root handle 100 taprio \
    num_tc 4 \
    map 0 1 2 3 3 3 3 3 3 3 3 3 3 3 3 3 \
    queues 1@0 1@1 1@2 1@3 \
    base-time $BASE \
    sched-entry S 0x8 500000 \
    sched-entry S 0x4 500000 \
    flags 0x2

2) Transmit the packet to closed gate. You may use udp_tai
application to transmit UDP packet to any of the closed gate.

./udp_tai -i <interface> -P 100000 -p 90 -c 1 -t <0/1> -u 30004

Fixes: ec50a9d437f0 ("igc: Add support for taprio offloading")
Co-developed-by: Tan Tee Min <tee.min.tan@linux.intel.com>
Signed-off-by: Tan Tee Min <tee.min.tan@linux.intel.com>
Tested-by: Chwee Lin Choong <chwee.lin.choong@intel.com>
Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 54 insertions, 4 deletions

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 7e22204822ea..e5bfc4000658 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -1572,6 +1572,9 @@ done:
 	first->bytecount = skb->len;
 	first->gso_segs = 1;
 
+	if (adapter->qbv_transition || tx_ring->oper_gate_closed)
+		goto out_drop;
+
 	if (tx_ring->max_sdu > 0) {
 		u32 max_sdu = 0;
 
@@ -3011,8 +3014,8 @@ static bool igc_clean_tx_irq(struct igc_q_vector *q_vector, int napi_budget)
 		    time_after(jiffies, tx_buffer->time_stamp +
 		    (adapter->tx_timeout_factor * HZ)) &&
 		    !(rd32(IGC_STATUS) & IGC_STATUS_TXOFF) &&
-		    (rd32(IGC_TDH(tx_ring->reg_idx)) !=
-		     readl(tx_ring->tail))) {
+		    (rd32(IGC_TDH(tx_ring->reg_idx)) != readl(tx_ring->tail)) &&
+		    !tx_ring->oper_gate_closed) {
 			/* detected Tx unit hang */
 			netdev_err(tx_ring->netdev,
 				   "Detected Tx Unit Hang\n"
@@ -6102,6 +6105,8 @@ static int igc_tsn_clear_schedule(struct igc_adapter *adapter)
 	adapter->base_time = 0;
 	adapter->cycle_time = NSEC_PER_SEC;
 	adapter->qbv_config_change_errors = 0;
+	adapter->qbv_transition = false;
+	adapter->qbv_count = 0;
 
 	for (i = 0; i < adapter->num_tx_queues; i++) {
 		struct igc_ring *ring = adapter->tx_ring[i];
@@ -6109,6 +6114,8 @@ static int igc_tsn_clear_schedule(struct igc_adapter *adapter)
 		ring->start_time = 0;
 		ring->end_time = NSEC_PER_SEC;
 		ring->max_sdu = 0;
+		ring->oper_gate_closed = false;
+		ring->admin_gate_closed = false;
 	}
 
 	return 0;
@@ -6120,6 +6127,7 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 	bool queue_configured[IGC_MAX_TX_QUEUES] = { };
 	struct igc_hw *hw = &adapter->hw;
 	u32 start_time = 0, end_time = 0;
+	struct timespec64 now;
 	size_t n;
 	int i;
 
@@ -6149,6 +6157,8 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 	adapter->cycle_time = qopt->cycle_time;
 	adapter->base_time = qopt->base_time;
 
+	igc_ptp_read(adapter, &now);
+
 	for (n = 0; n < qopt->num_entries; n++) {
 		struct tc_taprio_sched_entry *e = &qopt->entries[n];
 
@@ -6183,7 +6193,10 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 				ring->start_time = start_time;
 			ring->end_time = end_time;
 
-			queue_configured[i] = true;
+			if (ring->start_time >= adapter->cycle_time)
+				queue_configured[i] = false;
+			else
+				queue_configured[i] = true;
 		}
 
 		start_time += e->interval;
@@ -6193,8 +6206,20 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter,
 	 * If not, set the start and end time to be end time.
 	 */
 	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct igc_ring *ring = adapter->tx_ring[i];
+
+		if (!is_base_time_past(qopt->base_time, &now)) {
+			ring->admin_gate_closed = false;
+		} else {
+			ring->oper_gate_closed = false;
+			ring->admin_gate_closed = false;
+		}
+
 		if (!queue_configured[i]) {
-			struct igc_ring *ring = adapter->tx_ring[i];
+			if (!is_base_time_past(qopt->base_time, &now))
+				ring->admin_gate_closed = true;
+			else
+				ring->oper_gate_closed = true;
 
 			ring->start_time = end_time;
 			ring->end_time = end_time;
@@ -6575,6 +6600,27 @@ static const struct xdp_metadata_ops igc_xdp_metadata_ops = {
 	.xmo_rx_timestamp		= igc_xdp_rx_timestamp,
 };
 
+static enum hrtimer_restart igc_qbv_scheduling_timer(struct hrtimer *timer)
+{
+	struct igc_adapter *adapter = container_of(timer, struct igc_adapter,
+						   hrtimer);
+	unsigned int i;
+
+	adapter->qbv_transition = true;
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct igc_ring *tx_ring = adapter->tx_ring[i];
+
+		if (tx_ring->admin_gate_closed) {
+			tx_ring->admin_gate_closed = false;
+			tx_ring->oper_gate_closed = true;
+		} else {
+			tx_ring->oper_gate_closed = false;
+		}
+	}
+	adapter->qbv_transition = false;
+	return HRTIMER_NORESTART;
+}
+
 /**
  * igc_probe - Device Initialization Routine
  * @pdev: PCI device information struct
@@ -6753,6 +6799,9 @@ static int igc_probe(struct pci_dev *pdev,
 	INIT_WORK(&adapter->reset_task, igc_reset_task);
 	INIT_WORK(&adapter->watchdog_task, igc_watchdog_task);
 
+	hrtimer_init(&adapter->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	adapter->hrtimer.function = &igc_qbv_scheduling_timer;
+
 	/* Initialize link properties that are user-changeable */
 	adapter->fc_autoneg = true;
 	hw->mac.autoneg = true;
@@ -6856,6 +6905,7 @@ static void igc_remove(struct pci_dev *pdev)
 
 	cancel_work_sync(&adapter->reset_task);
 	cancel_work_sync(&adapter->watchdog_task);
+	hrtimer_cancel(&adapter->hrtimer);
 
 	/* Release control of h/w to f/w.  If f/w is AMT enabled, this
 	 * would have already happened in close and is redundant.