net: fs_enet: make rx_copybreak value configurable

Measurement shows that on a MPC8xx running at 132MHz, the optimal
limit is 112:
* 114 bytes packets are processed in 147 TB ticks with higher copybreak
* 114 bytes packets are processed in 148 TB ticks with lower copybreak
* 128 bytes packets are processed in 154 TB ticks with higher copybreak
* 128 bytes packets are processed in 148 TB ticks with lower copybreak
* 238 bytes packets are processed in 172 TB ticks with higher copybreak
* 238 bytes packets are processed in 148 TB ticks with lower copybreak

However it might be different on other processors
and/or frequencies. So it is useful to make it configurable.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
index f2a60cd1feed81022b893c53a37ae00bc86419a0..dc120c148d9766fcf511f100396cb51f4b61a73b 100644 (file)
--- a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
+++ b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
@@ -830,6 +830,44 @@ static void fs_set_msglevel(struct net_device *dev, u32 value)
        fep->msg_enable = value;
 }
 
+static int fs_get_tunable(struct net_device *dev,
+                         const struct ethtool_tunable *tuna, void *data)
+{
+       struct fs_enet_private *fep = netdev_priv(dev);
+       struct fs_platform_info *fpi = fep->fpi;
+       int ret = 0;
+
+       switch (tuna->id) {
+       case ETHTOOL_RX_COPYBREAK:
+               *(u32 *)data = fpi->rx_copybreak;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+       return ret;
+}
+
+static int fs_set_tunable(struct net_device *dev,
+                         const struct ethtool_tunable *tuna, const void *data)
+{
+       struct fs_enet_private *fep = netdev_priv(dev);
+       struct fs_platform_info *fpi = fep->fpi;
+       int ret = 0;
+
+       switch (tuna->id) {
+       case ETHTOOL_RX_COPYBREAK:
+               fpi->rx_copybreak = *(u32 *)data;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+       return ret;
+}
+
 static const struct ethtool_ops fs_ethtool_ops = {
        .get_drvinfo = fs_get_drvinfo,
        .get_regs_len = fs_get_regs_len,
@@ -841,6 +879,8 @@ static const struct ethtool_ops fs_ethtool_ops = {
        .get_ts_info = ethtool_op_get_ts_info,
        .get_link_ksettings = phy_ethtool_get_link_ksettings,
        .set_link_ksettings = phy_ethtool_set_link_ksettings,
+       .get_tunable = fs_get_tunable,
+       .set_tunable = fs_set_tunable,
 };
 
 static int fs_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)