igc: Add support for ETF offloading

This adds support for ETF offloading for the i225 controller.

For i225, the LaunchTime feature is almost a subset of the Qbv
feature. The main change from the i210 is that the launchtime of each
packet is specified as an offset applied to the BASET register. BASET
is automatically incremented each cycle.

For i225, the approach chosen is to re-use most of the setup used for
taprio offloading. With a few changes:

 - The more or less obvious one is that when ETF is enabled, we should
 set add the expected launchtime to the (advanced) transmit
 descriptor;

 - The less obvious, is that when taprio offloading is not enabled, we
 add a dummy schedule (all queues are open all the time, with a cycle
 time of 1 second).

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Reviewed-by: Andre Guedes <andre.guedes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index 257fe970afe8..174103c4bea6 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -4,6 +4,20 @@
 #include "igc.h"
 #include "igc_tsn.h"
 
+static bool is_any_launchtime(struct igc_adapter *adapter)
+{
+	int i;
+
+	for (i = 0; i < adapter->num_tx_queues; i++) {
+		struct igc_ring *ring = adapter->tx_ring[i];
+
+		if (ring->launchtime_enable)
+			return true;
+	}
+
+	return false;
+}
+
 /* Returns the TSN specific registers to their default values after
  * TSN offloading is disabled.
  */
@@ -88,6 +102,9 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 				IGC_TXQCTL_STRICT_END;
 		}
 
+		if (ring->launchtime_enable)
+			txqctl |= IGC_TXQCTL_QUEUE_MODE_LAUNCHT;
+
 		wr32(IGC_TXQCTL(i), txqctl);
 	}
 
@@ -115,7 +132,7 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 
 int igc_tsn_offload_apply(struct igc_adapter *adapter)
 {
-	bool is_any_enabled = adapter->base_time;
+	bool is_any_enabled = adapter->base_time || is_any_launchtime(adapter);
 
 	if (!(adapter->flags & IGC_FLAG_TSN_QBV_ENABLED) && !is_any_enabled)
 		return 0;