[PATCH net-next 0/2] net: stmmac: Disable EEE RX clock stop when VLAN is enabled

[PATCH net-next 0/2] net: stmmac: Disable EEE RX clock stop when VLAN is enabled

[Ovidiu Panait]

Hi,

This series fixes a couple of VLAN issues observed on the Renesas RZ/V2H
EVK platform (stmmac + Microchip KSZ9131RNXI PHY):

- The first patch fixes a bug where VLAN ID 0 would not be properly removed
due to how vlan_del_hw_rx_fltr() matched entries in the VLAN filter table.

- The second patch addresses RX clock gating issues that occur during VLAN
creation and deletion when EEE is enabled with RX clock-stop active (the
default configuration). For example:

    # ip link add link end1 name end1.5 type vlan id 5
    15c40000.ethernet end1: Timeout accessing MAC_VLAN_Tag_Filter
    RTNETLINK answers: Device or resource busy

The stmmac hardware requires the receive clock to be running when writing
certain registers, including VLAN registers. However, by default the driver
enables Energy Efficient Ethernet (EEE) and allows the PHY to stop the
receive clock when the link is idle. As a result, the RX clock might be
stopped when attempting to access these registers, leading to timeouts.

A more comprehensive overview of receive clock related issues in the
stmmac driver can be found here:
https://lore.kernel.org/all/Z9ySeo61VYTClIJJ@shell.armlinux.org.uk/

Most of the issues were resolved by commit dd557266cf5fb ("net: stmmac:
block PHY RXC clock-stop"), which wraps register accesses with
phylink_rx_clk_stop_block()/unblock() calls. However, VLAN add/delete
operations are invoked with bottom halves disabled, where sleeping is
not permitted, so those helpers cannot be used.

To avoid these VLAN timeouts, the second patch disables the EEE RX
clock-stop feature when VLAN support is enabled. This ensures the receive
clock remains active, allowing VLAN operations to complete successfully.

Best regards,
Ovidiu

Ovidiu Panait (2):
  net: stmmac: Fix VLAN 0 deletion in vlan_del_hw_rx_fltr()
  net: stmmac: Disable EEE RX clock stop when VLAN is enabled

 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 ++-
 drivers/net/ethernet/stmicro/stmmac/stmmac_vlan.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

-- 
2.51.0

[PATCH net-next 1/2] net: stmmac: Fix VLAN 0 deletion in vlan_del_hw_rx_fltr()

[Ovidiu Panait]

When the "rx-vlan-filter" feature is enabled on a network device, the 8021q
module automatically adds a VLAN 0 hardware filter when the device is
brought administratively up.

For stmmac, this causes vlan_add_hw_rx_fltr() to create a new entry for
VID 0 in the mac_device_info->vlan_filter array, in the following format:

    VLAN_TAG_DATA_ETV | VLAN_TAG_DATA_VEN | vid

Here, VLAN_TAG_DATA_VEN indicates that the hardware filter is enabled for
that VID.

However, on the delete path, vlan_del_hw_rx_fltr() searches the vlan_filter
array by VID only, without verifying whether a VLAN entry is enabled. As a
result, when the 8021q module attempts to remove VLAN 0, the function may
mistakenly match a zero-initialized slot rather than the actual VLAN 0
entry, causing incorrect deletions and leaving stale entries in the
hardware table.

Fix this by verifying that the VLAN entry's enable bit (VLAN_TAG_DATA_VEN)
is set before matching and deleting by VID. This ensures only active VLAN
entries are removed and avoids leaving stale entries in the VLAN filter
table, particularly for VLAN ID 0.

Fixes: ed64639bc1e08 ("net: stmmac: Add support for VLAN Rx filtering")
Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_vlan.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_vlan.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_vlan.c
index 0b6f6228ae35..fd97879a8740 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_vlan.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_vlan.c
@@ -122,7 +122,8 @@ static int vlan_del_hw_rx_fltr(struct net_device *dev,
 
 	/* Extended Rx VLAN Filter Enable */
 	for (i = 0; i < hw->num_vlan; i++) {
-		if ((hw->vlan_filter[i] & VLAN_TAG_DATA_VID) == vid) {
+		if ((hw->vlan_filter[i] & VLAN_TAG_DATA_VEN) &&
+		    ((hw->vlan_filter[i] & VLAN_TAG_DATA_VID) == vid)) {
 			ret = vlan_write_filter(dev, hw, i, 0);
 
 			if (!ret)
-- 
2.51.0

Re: [PATCH net-next 1/2] net: stmmac: Fix VLAN 0 deletion in vlan_del_hw_rx_fltr()

[Simon Horman]

On Tue, Nov 11, 2025 at 09:29:59AM +0000, Ovidiu Panait wrote:
> When the "rx-vlan-filter" feature is enabled on a network device, the 8021q
> module automatically adds a VLAN 0 hardware filter when the device is
> brought administratively up.
> 
> For stmmac, this causes vlan_add_hw_rx_fltr() to create a new entry for
> VID 0 in the mac_device_info->vlan_filter array, in the following format:
> 
>     VLAN_TAG_DATA_ETV | VLAN_TAG_DATA_VEN | vid
> 
> Here, VLAN_TAG_DATA_VEN indicates that the hardware filter is enabled for
> that VID.
> 
> However, on the delete path, vlan_del_hw_rx_fltr() searches the vlan_filter
> array by VID only, without verifying whether a VLAN entry is enabled. As a
> result, when the 8021q module attempts to remove VLAN 0, the function may
> mistakenly match a zero-initialized slot rather than the actual VLAN 0
> entry, causing incorrect deletions and leaving stale entries in the
> hardware table.
> 
> Fix this by verifying that the VLAN entry's enable bit (VLAN_TAG_DATA_VEN)
> is set before matching and deleting by VID. This ensures only active VLAN
> entries are removed and avoids leaving stale entries in the VLAN filter
> table, particularly for VLAN ID 0.
> 
> Fixes: ed64639bc1e08 ("net: stmmac: Add support for VLAN Rx filtering")
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

Reviewed-by: Simon Horman <horms@kernel.org>

[PATCH net-next 2/2] net: stmmac: Disable EEE RX clock stop when VLAN is enabled

[Ovidiu Panait]

On the Renesas RZ/V2H EVK platform, where the stmmac MAC is connected to a
Microchip KSZ9131RNXI PHY, creating or deleting VLAN interfaces may fail
with timeouts:

    # ip link add link end1 name end1.5 type vlan id 5
    15c40000.ethernet end1: Timeout accessing MAC_VLAN_Tag_Filter
    RTNETLINK answers: Device or resource busy

Disabling EEE at runtime avoids the problem:

    # ethtool --set-eee end1 eee off
    # ip link add link end1 name end1.5 type vlan id 5
    # ip link del end1.5

The stmmac hardware requires the receive clock to be running when writing
certain registers, such as those used for MAC address configuration or
VLAN filtering. However, by default the driver enables Energy Efficient
Ethernet (EEE) and allows the PHY to stop the receive clock when the link
is idle. As a result, the RX clock might be stopped when attempting to
access these registers, leading to timeouts and other issues.

Commit dd557266cf5fb ("net: stmmac: block PHY RXC clock-stop")
addressed this issue for most register accesses by wrapping them in
phylink_rx_clk_stop_block()/phylink_rx_clk_stop_unblock() calls.
However, VLAN add/delete operations may be invoked with bottom halves
disabled, where sleeping is not allowed, so using these helpers is not
possible.

Therefore, to fix this, disable the RX clock stop feature in the phylink
configuration if VLAN features are set. This ensures the RX clock remains
active and register accesses succeed during VLAN operations.

Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index ba4eeba14baa..0d3fb4fa5e12 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1245,7 +1245,8 @@ static int stmmac_phylink_setup(struct stmmac_priv *priv)
 	/* Stmmac always requires an RX clock for hardware initialization */
 	config->mac_requires_rxc = true;
 
-	if (!(priv->plat->flags & STMMAC_FLAG_RX_CLK_RUNS_IN_LPI))
+	if (!(priv->plat->flags & STMMAC_FLAG_RX_CLK_RUNS_IN_LPI) &&
+	    !(priv->dev->features & NETIF_F_VLAN_FEATURES))
 		config->eee_rx_clk_stop_enable = true;
 
 	/* Set the default transmit clock stop bit based on the platform glue */
-- 
2.51.0

Re: [PATCH net-next 2/2] net: stmmac: Disable EEE RX clock stop when VLAN is enabled

[Russell King (Oracle)]

On Tue, Nov 11, 2025 at 09:30:00AM +0000, Ovidiu Panait wrote:
> On the Renesas RZ/V2H EVK platform, where the stmmac MAC is connected to a
> Microchip KSZ9131RNXI PHY, creating or deleting VLAN interfaces may fail
> with timeouts:
> 
>     # ip link add link end1 name end1.5 type vlan id 5
>     15c40000.ethernet end1: Timeout accessing MAC_VLAN_Tag_Filter
>     RTNETLINK answers: Device or resource busy
> 
> Disabling EEE at runtime avoids the problem:
> 
>     # ethtool --set-eee end1 eee off
>     # ip link add link end1 name end1.5 type vlan id 5
>     # ip link del end1.5
> 
> The stmmac hardware requires the receive clock to be running when writing
> certain registers, such as those used for MAC address configuration or
> VLAN filtering. However, by default the driver enables Energy Efficient
> Ethernet (EEE) and allows the PHY to stop the receive clock when the link
> is idle. As a result, the RX clock might be stopped when attempting to
> access these registers, leading to timeouts and other issues.
> 
> Commit dd557266cf5fb ("net: stmmac: block PHY RXC clock-stop")
> addressed this issue for most register accesses by wrapping them in
> phylink_rx_clk_stop_block()/phylink_rx_clk_stop_unblock() calls.
> However, VLAN add/delete operations may be invoked with bottom halves
> disabled, where sleeping is not allowed, so using these helpers is not
> possible.
> 
> Therefore, to fix this, disable the RX clock stop feature in the phylink
> configuration if VLAN features are set. This ensures the RX clock remains
> active and register accesses succeed during VLAN operations.
> 
> Signed-off-by: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

Thanks for the patch. I guess there is no other way around this, since
as I've previously noted (and as you say above) we can't sleep in the
VLAN ops to access the PHY.

I would like a comment in the code above this if() to state that EEE
RX clock stop is disabled to allow access to VLAN registers to work.
With that added, please add:

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

-- 
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