From: Lorenzo Bianconi <lorenzo@kernel•org>
To: Andrew Lunn <andrew+netdev@lunn•ch>,
"David S. Miller" <davem@davemloft•net>,
Eric Dumazet <edumazet@google•com>,
Jakub Kicinski <kuba@kernel•org>,
Paolo Abeni <pabeni@redhat•com>, Rob Herring <robh@kernel•org>,
Krzysztof Kozlowski <krzk+dt@kernel•org>,
Conor Dooley <conor+dt@kernel•org>,
Lorenzo Bianconi <lorenzo@kernel•org>
Cc: Christian Marangi <ansuelsmth@gmail•com>,
Benjamin Larsson <benjamin.larsson@genexis•eu>,
linux-arm-kernel@lists•infradead.org,
linux-mediatek@lists•infradead.org, netdev@vger•kernel.org,
devicetree@vger•kernel.org, Xuegang Lu <xuegang.lu@airoha•com>
Subject: [PATCH net-next v9 4/6] net: airoha: Do not stop GDM port if it is shared
Date: Wed, 03 Jun 2026 08:00:18 +0200 [thread overview]
Message-ID: <20260603-airoha-eth-multi-serdes-v9-4-5d476bc2f426@kernel.org> (raw)
In-Reply-To: <20260603-airoha-eth-multi-serdes-v9-0-5d476bc2f426@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.
Moreover, always set in GDM_LONG_LEN_MASK field of REG_GDM_LEN_CFG
register the maximum MTU of all running net_devices connected to the same
GDM port.
Tested-by: Xuegang Lu <xuegang.lu@airoha•com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel•org>
---
drivers/net/ethernet/airoha/airoha_eth.c | 59 +++++++++++++++++++++++++-------
drivers/net/ethernet/airoha/airoha_eth.h | 1 +
2 files changed, 48 insertions(+), 12 deletions(-)
diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 1d088d95d5fb..44b77a5cc4c5 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -1720,8 +1720,8 @@ static int airoha_dev_open(struct net_device *netdev)
int err, len = ETH_HLEN + netdev->mtu + ETH_FCS_LEN;
struct airoha_gdm_dev *dev = netdev_priv(netdev);
struct airoha_gdm_port *port = dev->port;
+ u32 cur_len, pse_port = FE_PSE_PORT_PPE1;
struct airoha_qdma *qdma = dev->qdma;
- u32 pse_port = FE_PSE_PORT_PPE1;
netif_tx_start_all_queues(netdev);
err = airoha_set_vip_for_gdm_port(dev, true);
@@ -1735,10 +1735,20 @@ static int airoha_dev_open(struct net_device *netdev)
airoha_fe_clear(qdma->eth, REG_GDM_INGRESS_CFG(port->id),
GDM_STAG_EN_MASK);
- airoha_fe_rmw(qdma->eth, REG_GDM_LEN_CFG(port->id),
- GDM_SHORT_LEN_MASK | GDM_LONG_LEN_MASK,
- FIELD_PREP(GDM_SHORT_LEN_MASK, 60) |
- FIELD_PREP(GDM_LONG_LEN_MASK, len));
+ cur_len = airoha_fe_get(qdma->eth, REG_GDM_LEN_CFG(port->id),
+ GDM_LONG_LEN_MASK);
+ if (!port->users || len > cur_len) {
+ /* Opening a sibling net_device with a larger MTU updates the
+ * MTU of already running devices. This is required to allow
+ * multiple net_devices with different MTUs to share the same
+ * GDM port.
+ */
+ airoha_fe_rmw(qdma->eth, REG_GDM_LEN_CFG(port->id),
+ GDM_SHORT_LEN_MASK | GDM_LONG_LEN_MASK,
+ FIELD_PREP(GDM_SHORT_LEN_MASK, 60) |
+ FIELD_PREP(GDM_LONG_LEN_MASK, len));
+ }
+ port->users++;
airoha_qdma_set(qdma, REG_QDMA_GLOBAL_CFG,
GLOBAL_CFG_TX_DMA_EN_MASK |
@@ -1754,6 +1764,30 @@ static int airoha_dev_open(struct net_device *netdev)
return 0;
}
+static void airoha_set_port_mtu(struct airoha_eth *eth,
+ struct airoha_gdm_port *port)
+{
+ u32 len = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(port->devs); i++) {
+ struct airoha_gdm_dev *dev = port->devs[i];
+ struct net_device *netdev;
+
+ if (!dev)
+ continue;
+
+ netdev = netdev_from_priv(dev);
+ if (netif_running(netdev))
+ len = max_t(u32, len, netdev->mtu);
+ }
+ len += ETH_HLEN + ETH_FCS_LEN;
+
+ airoha_fe_rmw(eth, REG_GDM_LEN_CFG(port->id),
+ GDM_LONG_LEN_MASK,
+ FIELD_PREP(GDM_LONG_LEN_MASK, len));
+}
+
static int airoha_dev_stop(struct net_device *netdev)
{
struct airoha_gdm_dev *dev = netdev_priv(netdev);
@@ -1766,8 +1800,12 @@ static int airoha_dev_stop(struct net_device *netdev)
for (i = 0; i < netdev->num_tx_queues; 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 (--port->users)
+ airoha_set_port_mtu(dev->eth, port);
+ else
+ 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,
@@ -1922,13 +1960,10 @@ static int airoha_dev_change_mtu(struct net_device *netdev, int mtu)
{
struct airoha_gdm_dev *dev = netdev_priv(netdev);
struct airoha_gdm_port *port = dev->port;
- u32 len = ETH_HLEN + mtu + ETH_FCS_LEN;
- struct airoha_eth *eth = dev->eth;
- airoha_fe_rmw(eth, REG_GDM_LEN_CFG(port->id),
- GDM_LONG_LEN_MASK,
- FIELD_PREP(GDM_LONG_LEN_MASK, len));
WRITE_ONCE(netdev->mtu, mtu);
+ if (port->users)
+ airoha_set_port_mtu(dev->eth, port);
return 0;
}
diff --git a/drivers/net/ethernet/airoha/airoha_eth.h b/drivers/net/ethernet/airoha/airoha_eth.h
index 92fd81bb9269..666e9246e70e 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.h
+++ b/drivers/net/ethernet/airoha/airoha_eth.h
@@ -554,6 +554,7 @@ struct airoha_gdm_dev {
struct airoha_gdm_port {
struct airoha_gdm_dev *devs[AIROHA_MAX_NUM_GDM_DEVS];
int id;
+ int users;
struct airoha_hw_stats stats;
--
2.54.0
next prev parent reply other threads:[~2026-06-03 6:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-03 6:00 [PATCH net-next v9 0/6] net: airoha: Support multiple net_devices connected to the same GDM port Lorenzo Bianconi
2026-06-03 6:00 ` [PATCH net-next v9 1/6] dt-bindings: net: airoha: Add GDM port ethernet child node Lorenzo Bianconi
2026-06-03 6:00 ` [PATCH net-next v9 2/6] net: airoha: Remove private net_device pointer in airoha_gdm_dev struct Lorenzo Bianconi
2026-06-03 6:00 ` [PATCH net-next v9 3/6] net: airoha: Support multiple net_devices for a single FE GDM port Lorenzo Bianconi
2026-06-04 8:41 ` Lorenzo Bianconi
2026-06-03 6:00 ` Lorenzo Bianconi [this message]
2026-06-03 6:00 ` [PATCH net-next v9 5/6] net: airoha: Introduce WAN device flag Lorenzo Bianconi
2026-06-03 6:00 ` [PATCH net-next v9 6/6] net: airoha: Support multiple LAN/WAN interfaces for hw MAC address configuration Lorenzo Bianconi
2026-06-04 9:20 ` Lorenzo Bianconi
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