[PATCH net-next 09/10] net: airoha: Do not stop GDM port if it is shared

[Lorenzo Bianconi <lorenzo@kernel.org>]

Theoretically, in the current codebase, two independent net_devices can
be connected to the same GDM port so we need to check the GDM port is not
used by any other running net_device before setting the forward
configuration to FE_PSE_PORT_DROP.

Tested-by: Xuegang Lu <xuegang.lu@airoha.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/airoha/airoha_eth.c | 9 ++++++---
 drivers/net/ethernet/airoha/airoha_eth.h | 2 ++
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 11b6dbf3fa80c0c7620fc912b4db904eb5711b2c..3926866e711e51bb20665dfda464c5283b7616fa 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -1662,6 +1662,7 @@ static int airoha_dev_open(struct net_device *netdev)
 	}
 	airoha_set_gdm_port_fwd_cfg(qdma->eth, REG_GDM_FWD_CFG(port->id),
 				    pse_port);
+	atomic_inc(&port->users);
 
 	return 0;
 }
@@ -1681,9 +1682,6 @@ static int airoha_dev_stop(struct net_device *netdev)
 	for (i = 0; i < ARRAY_SIZE(qdma->q_tx); i++)
 		netdev_tx_reset_subqueue(netdev, i);
 
-	airoha_set_gdm_port_fwd_cfg(qdma->eth, REG_GDM_FWD_CFG(port->id),
-				    FE_PSE_PORT_DROP);
-
 	if (atomic_dec_and_test(&qdma->users)) {
 		airoha_qdma_clear(qdma, REG_QDMA_GLOBAL_CFG,
 				  GLOBAL_CFG_TX_DMA_EN_MASK |
@@ -1697,6 +1695,11 @@ static int airoha_dev_stop(struct net_device *netdev)
 		}
 	}
 
+	if (atomic_dec_and_test(&port->users))
+		airoha_set_gdm_port_fwd_cfg(qdma->eth,
+					    REG_GDM_FWD_CFG(port->id),
+					    FE_PSE_PORT_DROP);
+
 	return 0;
 }
 
diff --git a/drivers/net/ethernet/airoha/airoha_eth.h b/drivers/net/ethernet/airoha/airoha_eth.h
index 7549960fc37c68a5df73c49eace0aa57fda98030..c076e36b741ce691cf309850435c352fc1fd7986 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.h
+++ b/drivers/net/ethernet/airoha/airoha_eth.h
@@ -546,6 +546,8 @@ struct airoha_gdm_port {
 	struct airoha_gdm_dev *devs[AIROHA_MAX_NUM_GDM_DEVS];
 	int id;
 
+	atomic_t users;
+
 	struct airoha_hw_stats stats;
 
 	DECLARE_BITMAP(qos_sq_bmap, AIROHA_NUM_QOS_CHANNELS);

-- 
2.53.0