igc: set the RX packet buffer size for TSN mode

In preparation for supporting frame preemption, when entering TSN mode,
set the receive packet buffer to 15KB for the Express MAC, 15KB for
the Preemptible MAC and 2KB for the BMC.

References:
I225/I226 SW User Manual, Section 4.7.9, Section 7.1.3.2, Section 8.3.1

The newly introduced macros follow the naming from the i226 SW User Manual
for easy reference.

Co-developed-by: Vinicius Costa Gomes <[email protected]>
Signed-off-by: Vinicius Costa Gomes <[email protected]>
Signed-off-by: Faizal Rahim <[email protected]>
Tested-by: Mor Bar-Gabay <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c
index 498741d83ca6..2254f255cc3b 100644
--- a/drivers/net/ethernet/intel/igc/igc_tsn.c
+++ b/drivers/net/ethernet/intel/igc/igc_tsn.c
@@ -125,6 +125,29 @@ static void igc_tsn_tx_arb(struct igc_adapter *adapter, u16 *queue_per_tc)
 	wr32(IGC_TXARB, txarb);
 }
 
+/**
+ * igc_tsn_set_rxpbsize - Set the receive packet buffer size
+ * @adapter: Pointer to the igc_adapter structure
+ * @rxpbs_exp_bmc_be: Value to set the receive packet buffer size, including
+ *                    express buffer, BMC buffer, and Best Effort buffer
+ *
+ * The IGC_RXPBS register value may include allocations for the Express buffer,
+ * BMC buffer, Best Effort buffer, and the timestamp descriptor buffer
+ * (IGC_RXPBS_CFG_TS_EN).
+ */
+static void igc_tsn_set_rxpbsize(struct igc_adapter *adapter,
+				 u32 rxpbs_exp_bmc_be)
+{
+	struct igc_hw *hw = &adapter->hw;
+	u32 rxpbs = rd32(IGC_RXPBS);
+
+	rxpbs &= ~(IGC_RXPBSIZE_EXP_MASK | IGC_BMC2OSPBSIZE_MASK |
+		   IGC_RXPBSIZE_BE_MASK);
+	rxpbs |= rxpbs_exp_bmc_be;
+
+	wr32(IGC_RXPBS, rxpbs);
+}
+
 /* Returns the TSN specific registers to their default values after
  * the adapter is reset.
  */
@@ -139,6 +162,8 @@ static int igc_tsn_disable_offload(struct igc_adapter *adapter)
 	wr32(IGC_TXPBS, IGC_TXPBSIZE_DEFAULT);
 	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_DEFAULT);
 
+	igc_tsn_set_rxpbsize(adapter, IGC_RXPBSIZE_EXP_BMC_DEFAULT);
+
 	if (igc_is_device_id_i226(hw))
 		igc_tsn_restore_retx_default(adapter);
 
@@ -202,6 +227,8 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter)
 	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_TSN);
 	wr32(IGC_TXPBS, IGC_TXPBSIZE_TSN);
 
+	igc_tsn_set_rxpbsize(adapter, IGC_RXPBSIZE_EXP_BMC_BE_TSN);
+
 	if (igc_is_device_id_i226(hw))
 		igc_tsn_set_retx_qbvfullthreshold(adapter);