[net-next PATCH v3 1/6] net: dsa: qca8k: drop MTU tracking from qca8k_priv

Ansuel Smith
2022-04-15T23:30:28Z

DSA set the CPU port based on the largest MTU of all the slave ports.
Based on this we can drop the MTU array from qca8k_priv and set the
port_change_mtu logic on DSA changing MTU of the CPU port as the switch
have a global MTU settingfor each port.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
---
drivers/net/dsa/qca8k.c | 26 +++++++++-----------------
drivers/net/dsa/qca8k.h | 1 -
2 files changed, 9 insertions(+), 18 deletions(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index d3ed0a7f8077..4e27d9803a5f 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -2367,16 +2367,18 @@ static int
qca8k_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
{
struct qca8k_priv *priv = ds->priv;
- int i, mtu = 0;

- priv->port_mtu[port] = new_mtu;
-
- for (i = 0; i < QCA8K_NUM_PORTS; i++)
- if (priv->port_mtu[i] > mtu)
- mtu = priv->port_mtu[i];
+ /* We have only have a general MTU setting.
+ * DSA always set the CPU port's MTU to the largest MTU of the slave
+ * ports.
+ * Setting MTU just for the CPU port is sufficient to correctly set a
+ * value for every port.
+ */
+ if (!dsa_is_cpu_port(ds, port))
+ return 0;

/* Include L2 header / FCS length */
- return qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, mtu + ETH_HLEN + ETH_FCS_LEN);
+ return qca8k_write(priv, QCA8K_MAX_FRAME_SIZE, new_mtu + ETH_HLEN + ETH_FCS_LEN);
}

static int
@@ -3033,16 +3035,6 @@ qca8k_setup(struct dsa_switch *ds)
QCA8K_PORT_HOL_CTRL1_WRED_EN,
mask);
}
-
- /* Set initial MTU for every port.
- * We have only have a general MTU setting. So track
- * every port and set the max across all port.
- * Set per port MTU to 1500 as the MTU change function
- * will add the overhead and if its set to 1518 then it
- * will apply the overhead again and we will end up with
- * MTU of 1536 instead of 1518
- */
- priv->port_mtu[i] = ETH_DATA_LEN;
}

/* Special GLOBAL_FC_THRESH value are needed for ar8327 switch */
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index f375627174c8..562d75997e55 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -398,7 +398,6 @@ struct qca8k_priv {
struct device *dev;
struct dsa_switch_ops ops;
struct gpio_desc *reset_gpio;
- unsigned int port_mtu[QCA8K_NUM_PORTS];
struct net_device *mgmt_master; /* Track if mdio/mib Ethernet is available */
struct qca8k_mgmt_eth_data mgmt_eth_data;
struct qca8k_mib_eth_data mib_eth_data;
--
2.34.1