diff mbox series

[v2,4/6] net: ocelot: add support for ndo_change_mtu

Message ID 20211103091943.3878621-5-clement.leger@bootlin.com (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series Add FDMA support on ocelot switch driver | expand

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netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 40 lines checked
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netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply, async

Commit Message

Clément Léger Nov. 3, 2021, 9:19 a.m. UTC 
This commit adds support for changing MTU for the ocelot register based
interface. For ocelot, JUMBO frame size can be set up to 25000 bytes
but has been set to 9000 which is a saner value and allow for maximum
gain of performances. Frames larger than 9000 bytes do not yield
a noticeable improvement.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
---
 drivers/net/ethernet/mscc/ocelot.h     |  2 ++
 drivers/net/ethernet/mscc/ocelot_net.c | 14 ++++++++++++++
 2 files changed, 16 insertions(+)

Comments

Vladimir Oltean Nov. 3, 2021, 12:40 p.m. UTC | #1 
On Wed, Nov 03, 2021 at 10:19:41AM +0100, Clément Léger wrote:
> This commit adds support for changing MTU for the ocelot register based
> interface. For ocelot, JUMBO frame size can be set up to 25000 bytes
> but has been set to 9000 which is a saner value and allow for maximum
> gain of performances. Frames larger than 9000 bytes do not yield
> a noticeable improvement.
> 
> Signed-off-by: Clément Léger <clement.leger@bootlin.com>
> ---
>  drivers/net/ethernet/mscc/ocelot.h     |  2 ++
>  drivers/net/ethernet/mscc/ocelot_net.c | 14 ++++++++++++++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/drivers/net/ethernet/mscc/ocelot.h b/drivers/net/ethernet/mscc/ocelot.h
> index e43da09b8f91..ba0dec7dd64f 100644
> --- a/drivers/net/ethernet/mscc/ocelot.h
> +++ b/drivers/net/ethernet/mscc/ocelot.h
> @@ -32,6 +32,8 @@
>  
>  #define OCELOT_PTP_QUEUE_SZ	128
>  
> +#define OCELOT_JUMBO_MTU	9000
> +
>  struct ocelot_port_tc {
>  	bool block_shared;
>  	unsigned long offload_cnt;
> diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c
> index d76def435b23..5916492fd6d0 100644
> --- a/drivers/net/ethernet/mscc/ocelot_net.c
> +++ b/drivers/net/ethernet/mscc/ocelot_net.c
> @@ -482,6 +482,18 @@ static netdev_tx_t ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
>  	return NETDEV_TX_OK;
>  }
>  
> +static int ocelot_change_mtu(struct net_device *dev, int new_mtu)
> +{
> +	struct ocelot_port_private *priv = netdev_priv(dev);
> +	struct ocelot_port *ocelot_port = &priv->port;
> +	struct ocelot *ocelot = ocelot_port->ocelot;
> +
> +	ocelot_port_set_maxlen(ocelot, priv->chip_port, new_mtu);
> +	WRITE_ONCE(dev->mtu, new_mtu);

The WRITE_ONCE seems absolutely gratuitous to me.

> +
> +	return 0;
> +}
> +
>  enum ocelot_action_type {
>  	OCELOT_MACT_LEARN,
>  	OCELOT_MACT_FORGET,
> @@ -768,6 +780,7 @@ static const struct net_device_ops ocelot_port_netdev_ops = {
>  	.ndo_open			= ocelot_port_open,
>  	.ndo_stop			= ocelot_port_stop,
>  	.ndo_start_xmit			= ocelot_port_xmit,
> +	.ndo_change_mtu			= ocelot_change_mtu,
>  	.ndo_set_rx_mode		= ocelot_set_rx_mode,
>  	.ndo_set_mac_address		= ocelot_port_set_mac_address,
>  	.ndo_get_stats64		= ocelot_get_stats64,
> @@ -1699,6 +1712,7 @@ int ocelot_probe_port(struct ocelot *ocelot, int port, struct regmap *target,
>  
>  	dev->netdev_ops = &ocelot_port_netdev_ops;
>  	dev->ethtool_ops = &ocelot_ethtool_ops;
> +	dev->max_mtu = OCELOT_JUMBO_MTU;
>  
>  	dev->hw_features |= NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_RXFCS |
>  		NETIF_F_HW_TC;
> -- 
> 2.33.0
>
Clément Léger Nov. 3, 2021, 1:07 p.m. UTC | #2 
Le Wed, 3 Nov 2021 12:40:55 +0000,
Vladimir Oltean <vladimir.oltean@nxp.com> a écrit :

> > +static int ocelot_change_mtu(struct net_device *dev, int new_mtu)
> > +{
> > +	struct ocelot_port_private *priv = netdev_priv(dev);
> > +	struct ocelot_port *ocelot_port = &priv->port;
> > +	struct ocelot *ocelot = ocelot_port->ocelot;
> > +
> > +	ocelot_port_set_maxlen(ocelot, priv->chip_port, new_mtu);
> > +	WRITE_ONCE(dev->mtu, new_mtu);  
> 
> The WRITE_ONCE seems absolutely gratuitous to me.

I applied what is recommended in netdevice.h for the mtu field of the
netdev.
(https://elixir.bootlin.com/linux/v5.15/source/include/linux/netdevice.h#L1989)
And used in __dev_set_mtu
(https://elixir.bootlin.com/linux/v5.15/source/net/core/dev.c#L8849)

> 
> > +
> > +	return 0;
> > +}
> > +
> >  enum ocelot_action_type {
> >  	OCELOT_MACT_LEARN,
> >  	OCELOT_MACT_FORGET,
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mscc/ocelot.h b/drivers/net/ethernet/mscc/ocelot.h
index e43da09b8f91..ba0dec7dd64f 100644
--- a/drivers/net/ethernet/mscc/ocelot.h
+++ b/drivers/net/ethernet/mscc/ocelot.h
@@ -32,6 +32,8 @@ 
 
 #define OCELOT_PTP_QUEUE_SZ	128
 
+#define OCELOT_JUMBO_MTU	9000
+
 struct ocelot_port_tc {
 	bool block_shared;
 	unsigned long offload_cnt;
diff --git a/drivers/net/ethernet/mscc/ocelot_net.c b/drivers/net/ethernet/mscc/ocelot_net.c
index d76def435b23..5916492fd6d0 100644
--- a/drivers/net/ethernet/mscc/ocelot_net.c
+++ b/drivers/net/ethernet/mscc/ocelot_net.c
@@ -482,6 +482,18 @@  static netdev_tx_t ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
 	return NETDEV_TX_OK;
 }
 
+static int ocelot_change_mtu(struct net_device *dev, int new_mtu)
+{
+	struct ocelot_port_private *priv = netdev_priv(dev);
+	struct ocelot_port *ocelot_port = &priv->port;
+	struct ocelot *ocelot = ocelot_port->ocelot;
+
+	ocelot_port_set_maxlen(ocelot, priv->chip_port, new_mtu);
+	WRITE_ONCE(dev->mtu, new_mtu);
+
+	return 0;
+}
+
 enum ocelot_action_type {
 	OCELOT_MACT_LEARN,
 	OCELOT_MACT_FORGET,
@@ -768,6 +780,7 @@  static const struct net_device_ops ocelot_port_netdev_ops = {
 	.ndo_open			= ocelot_port_open,
 	.ndo_stop			= ocelot_port_stop,
 	.ndo_start_xmit			= ocelot_port_xmit,
+	.ndo_change_mtu			= ocelot_change_mtu,
 	.ndo_set_rx_mode		= ocelot_set_rx_mode,
 	.ndo_set_mac_address		= ocelot_port_set_mac_address,
 	.ndo_get_stats64		= ocelot_get_stats64,
@@ -1699,6 +1712,7 @@  int ocelot_probe_port(struct ocelot *ocelot, int port, struct regmap *target,
 
 	dev->netdev_ops = &ocelot_port_netdev_ops;
 	dev->ethtool_ops = &ocelot_ethtool_ops;
+	dev->max_mtu = OCELOT_JUMBO_MTU;
 
 	dev->hw_features |= NETIF_F_HW_VLAN_CTAG_FILTER | NETIF_F_RXFCS |
 		NETIF_F_HW_TC;