diff options
| author | Vincent Whitchurch <vincent.whitchurch@axis.com> | 2021-11-26 18:51:15 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-08 11:04:49 +0300 |
| commit | 823ae758c0f3f787811b57c13e359f1b3d3877b5 (patch) | |
| tree | d7f91e044befeb6f4d76579ae5dd97885ac4ccf4 /drivers/net/ethernet/stmicro/stmmac | |
| parent | a927f9dfd0d92b74800fe634b383851b58fa3b62 (diff) | |
| download | linux-823ae758c0f3f787811b57c13e359f1b3d3877b5.tar.xz | |
net: stmmac: Avoid DMA_CHAN_CONTROL write if no Split Header support
commit f8e7dfd6fdabb831846ab1970a875746559d491b upstream.
The driver assumes that split headers can be enabled/disabled without
stopping/starting the device, so it writes DMA_CHAN_CONTROL from
stmmac_set_features(). However, on my system (IP v5.10a without Split
Header support), simply writing DMA_CHAN_CONTROL when DMA is running
(for example, with the commands below) leads to a TX watchdog timeout.
host$ socat TCP-LISTEN:1024,fork,reuseaddr - &
device$ ethtool -K eth0 tso off
device$ ethtool -K eth0 tso on
device$ dd if=/dev/zero bs=1M count=10 | socat - TCP4:host:1024
<tx watchdog timeout>
Note that since my IP is configured without Split Header support, the
driver always just reads and writes the same value to the
DMA_CHAN_CONTROL register.
I don't have access to any platforms with Split Header support so I
don't know if these writes to the DMA_CHAN_CONTROL while DMA is running
actually work properly on such systems. I could not find anything in
the databook that says that DMA_CHAN_CONTROL should not be written when
the DMA is running.
But on systems without Split Header support, there is in any case no
need to call enable_sph() in stmmac_set_features() at all since SPH can
never be toggled, so we can avoid the watchdog timeout there by skipping
this call.
Fixes: 8c6fc097a2f4acf ("net: stmmac: gmac4+: Add Split Header support")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net/ethernet/stmicro/stmmac')
| -rw-r--r-- | drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 1cf94248c221..3422f0746d82 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -5531,8 +5531,6 @@ static int stmmac_set_features(struct net_device *netdev, netdev_features_t features) { struct stmmac_priv *priv = netdev_priv(netdev); - bool sph_en; - u32 chan; /* Keep the COE Type in case of csum is supporting */ if (features & NETIF_F_RXCSUM) @@ -5544,10 +5542,13 @@ static int stmmac_set_features(struct net_device *netdev, */ stmmac_rx_ipc(priv, priv->hw); - sph_en = (priv->hw->rx_csum > 0) && priv->sph; + if (priv->sph_cap) { + bool sph_en = (priv->hw->rx_csum > 0) && priv->sph; + u32 chan; - for (chan = 0; chan < priv->plat->rx_queues_to_use; chan++) - stmmac_enable_sph(priv, priv->ioaddr, sph_en, chan); + for (chan = 0; chan < priv->plat->rx_queues_to_use; chan++) + stmmac_enable_sph(priv, priv->ioaddr, sph_en, chan); + } return 0; } |