[SRU][J:linux-bluefield][PATCH v1 1/1] UBUNTU: SAUCE: mlxbf_gige: add RX_DMA disable to NAPI poll routine

[David Thompson]

BugLink: https://bugs.launchpad.net/bugs/2049930

After configuring many IP interfaces, including oob_net0 managed by
mlxbf_gige driver, there are periodic connectivity problems to the
oob_net0 IP address.  This issue is a regression that started after
including these two commits into the kernel:
   revert "UBUNTU: SAUCE: Fix OOB handling RX packets in heavy traffic"
   addition of upstream "mlxbf_gige: fix receive packet race condition"
The fix is to modify the mlxbf_gige driver to include the RX_DMA disable
logic in its NAPI poll routine.  This logic was part of
   "UBUNTU: SAUCE: Fix OOB handling RX packets in heavy traffic"
but not part of
   upstream "mlxbf_gige: fix receive packet race condition"

Reviewed-by: Asmaa Mnebhi <asmaa at nvidia.com>
Signed-off-by: David Thompson <davthompson at nvidia.com>
---
 drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c
index 1a1eca08bfb9..a18fa860e5cc 100644
--- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c
+++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c
@@ -308,6 +308,10 @@ int mlxbf_gige_poll(struct napi_struct *napi, int budget)
 
 	mlxbf_gige_handle_tx_complete(priv);
 
+	data = readq(priv->base + MLXBF_GIGE_RX_DMA);
+	data &= ~MLXBF_GIGE_RX_DMA_EN;
+	writeq(data, priv->base + MLXBF_GIGE_RX_DMA);
+
 	do {
 		remaining_pkts = mlxbf_gige_rx_packet(priv, &work_done);
 	} while (remaining_pkts && work_done < budget);
@@ -323,6 +327,10 @@ int mlxbf_gige_poll(struct napi_struct *napi, int budget)
 		data = readq(priv->base + MLXBF_GIGE_INT_MASK);
 		data &= ~MLXBF_GIGE_INT_MASK_RX_RECEIVE_PACKET;
 		writeq(data, priv->base + MLXBF_GIGE_INT_MASK);
+
+		data = readq(priv->base + MLXBF_GIGE_RX_DMA);
+		data |= MLXBF_GIGE_RX_DMA_EN;
+		writeq(data, priv->base + MLXBF_GIGE_RX_DMA);
 	}
 
 	return work_done;
-- 
2.30.1