[PATCH net-next 1/5] net: gemini: Look up L3 maxlen from table

[PATCH net-next 1/5] net: gemini: Look up L3 maxlen from table

[Linus Walleij]

The code to calculate the hardware register enumerator
for the maximum L3 length isn't entirely simple to read.
Use the existing defines and rewrite the function into a
table look-up.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 61 ++++++++++++++++++++-------
 1 file changed, 46 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 6d7404f66f84..8fc31723f700 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -401,26 +401,57 @@ static int gmac_setup_phy(struct net_device *netdev)
 	return 0;
 }
 
-static int gmac_pick_rx_max_len(int max_l3_len)
-{
-	/* index = CONFIG_MAXLEN_XXX values */
-	static const int max_len[8] = {
-		1536, 1518, 1522, 1542,
-		9212, 10236, 1518, 1518
-	};
-	int i, n = 5;
+/* The maximum frame length is not logically enumerated in the
+ * hardware, so we do a table lookup to find the applicable max
+ * frame length.
+ */
+struct gmac_max_framelen {
+	unsigned int max_l3_len;
+	u8 val;
+};
 
-	max_l3_len += ETH_HLEN + VLAN_HLEN;
+static const struct gmac_max_framelen gmac_maxlens[] = {
+	{
+		.max_l3_len = 1518,
+		.val = CONFIG0_MAXLEN_1518,
+	},
+	{
+		.max_l3_len = 1522,
+		.val = CONFIG0_MAXLEN_1522,
+	},
+	{
+		.max_l3_len = 1536,
+		.val = CONFIG0_MAXLEN_1536,
+	},
+	{
+		.max_l3_len = 1542,
+		.val = CONFIG0_MAXLEN_1542,
+	},
+	{
+		.max_l3_len = 9212,
+		.val = CONFIG0_MAXLEN_9k,
+	},
+	{
+		.max_l3_len = 10236,
+		.val = CONFIG0_MAXLEN_10k,
+	},
+};
+
+static int gmac_pick_rx_max_len(unsigned int max_l3_len)
+{
+	const struct gmac_max_framelen *maxlen;
+	int maxtot;
+	int i;
 
-	if (max_l3_len > max_len[n])
-		return -1;
+	maxtot = max_l3_len + ETH_HLEN + VLAN_HLEN;
 
-	for (i = 0; i < 5; i++) {
-		if (max_len[i] >= max_l3_len && max_len[i] < max_len[n])
-			n = i;
+	for (i = 0; i < ARRAY_SIZE(gmac_maxlens); i++) {
+		maxlen = &gmac_maxlens[i];
+		if (maxtot <= maxlen->max_l3_len)
+			return maxlen->val;
 	}
 
-	return n;
+	return -1;
 }
 
 static int gmac_init(struct net_device *netdev)
-- 
2.17.1

[PATCH net-next 1/5] net: gemini: Look up L3 maxlen from table

[Linus Walleij]

The code to calculate the hardware register enumerator
for the maximum L3 length isn't entirely simple to read.
Use the existing defines and rewrite the function into a
table look-up.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 61 ++++++++++++++++++++-------
 1 file changed, 46 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 6d7404f66f84..8fc31723f700 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -401,26 +401,57 @@ static int gmac_setup_phy(struct net_device *netdev)
 	return 0;
 }
 
-static int gmac_pick_rx_max_len(int max_l3_len)
-{
-	/* index = CONFIG_MAXLEN_XXX values */
-	static const int max_len[8] = {
-		1536, 1518, 1522, 1542,
-		9212, 10236, 1518, 1518
-	};
-	int i, n = 5;
+/* The maximum frame length is not logically enumerated in the
+ * hardware, so we do a table lookup to find the applicable max
+ * frame length.
+ */
+struct gmac_max_framelen {
+	unsigned int max_l3_len;
+	u8 val;
+};
 
-	max_l3_len += ETH_HLEN + VLAN_HLEN;
+static const struct gmac_max_framelen gmac_maxlens[] = {
+	{
+		.max_l3_len = 1518,
+		.val = CONFIG0_MAXLEN_1518,
+	},
+	{
+		.max_l3_len = 1522,
+		.val = CONFIG0_MAXLEN_1522,
+	},
+	{
+		.max_l3_len = 1536,
+		.val = CONFIG0_MAXLEN_1536,
+	},
+	{
+		.max_l3_len = 1542,
+		.val = CONFIG0_MAXLEN_1542,
+	},
+	{
+		.max_l3_len = 9212,
+		.val = CONFIG0_MAXLEN_9k,
+	},
+	{
+		.max_l3_len = 10236,
+		.val = CONFIG0_MAXLEN_10k,
+	},
+};
+
+static int gmac_pick_rx_max_len(unsigned int max_l3_len)
+{
+	const struct gmac_max_framelen *maxlen;
+	int maxtot;
+	int i;
 
-	if (max_l3_len > max_len[n])
-		return -1;
+	maxtot = max_l3_len + ETH_HLEN + VLAN_HLEN;
 
-	for (i = 0; i < 5; i++) {
-		if (max_len[i] >= max_l3_len && max_len[i] < max_len[n])
-			n = i;
+	for (i = 0; i < ARRAY_SIZE(gmac_maxlens); i++) {
+		maxlen = &gmac_maxlens[i];
+		if (maxtot <= maxlen->max_l3_len)
+			return maxlen->val;
 	}
 
-	return n;
+	return -1;
 }
 
 static int gmac_init(struct net_device *netdev)
-- 
2.17.1

[PATCH net-next 2/5] net: gemini: Improve connection prints

[Linus Walleij]

Instead of just specify that a PHY is connected at some
speed, also specify which one. This is helpful with several
PHYs on the system.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 8fc31723f700..b49ed8964026 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -300,23 +300,26 @@ static void gmac_speed_set(struct net_device *netdev)
 		status.bits.speed = GMAC_SPEED_1000;
 		if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
 			status.bits.mii_rmii = GMAC_PHY_RGMII_1000;
-		netdev_info(netdev, "connect to RGMII @ 1Gbit\n");
+		netdev_info(netdev, "connect %s to RGMII @ 1Gbit\n",
+			    phydev_name(phydev));
 		break;
 	case 100:
 		status.bits.speed = GMAC_SPEED_100;
 		if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
 			status.bits.mii_rmii = GMAC_PHY_RGMII_100_10;
-		netdev_info(netdev, "connect to RGMII @ 100 Mbit\n");
+		netdev_info(netdev, "connect %s to RGMII @ 100 Mbit\n",
+			    phydev_name(phydev));
 		break;
 	case 10:
 		status.bits.speed = GMAC_SPEED_10;
 		if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
 			status.bits.mii_rmii = GMAC_PHY_RGMII_100_10;
-		netdev_info(netdev, "connect to RGMII @ 10 Mbit\n");
+		netdev_info(netdev, "connect %s to RGMII @ 10 Mbit\n",
+			    phydev_name(phydev));
 		break;
 	default:
-		netdev_warn(netdev, "Not supported PHY speed (%d)\n",
-			    phydev->speed);
+		netdev_warn(netdev, "Unsupported PHY speed (%d) on %s\n",
+			    phydev->speed, phydev_name(phydev));
 	}
 
 	if (phydev->duplex == DUPLEX_FULL) {
-- 
2.17.1

[PATCH net-next 2/5] net: gemini: Improve connection prints

[Linus Walleij]

Instead of just specify that a PHY is connected at some
speed, also specify which one. This is helpful with several
PHYs on the system.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 8fc31723f700..b49ed8964026 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -300,23 +300,26 @@ static void gmac_speed_set(struct net_device *netdev)
 		status.bits.speed = GMAC_SPEED_1000;
 		if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
 			status.bits.mii_rmii = GMAC_PHY_RGMII_1000;
-		netdev_info(netdev, "connect to RGMII @ 1Gbit\n");
+		netdev_info(netdev, "connect %s to RGMII @ 1Gbit\n",
+			    phydev_name(phydev));
 		break;
 	case 100:
 		status.bits.speed = GMAC_SPEED_100;
 		if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
 			status.bits.mii_rmii = GMAC_PHY_RGMII_100_10;
-		netdev_info(netdev, "connect to RGMII @ 100 Mbit\n");
+		netdev_info(netdev, "connect %s to RGMII @ 100 Mbit\n",
+			    phydev_name(phydev));
 		break;
 	case 10:
 		status.bits.speed = GMAC_SPEED_10;
 		if (phydev->interface == PHY_INTERFACE_MODE_RGMII)
 			status.bits.mii_rmii = GMAC_PHY_RGMII_100_10;
-		netdev_info(netdev, "connect to RGMII @ 10 Mbit\n");
+		netdev_info(netdev, "connect %s to RGMII @ 10 Mbit\n",
+			    phydev_name(phydev));
 		break;
 	default:
-		netdev_warn(netdev, "Not supported PHY speed (%d)\n",
-			    phydev->speed);
+		netdev_warn(netdev, "Unsupported PHY speed (%d) on %s\n",
+			    phydev->speed, phydev_name(phydev));
 	}
 
 	if (phydev->duplex == DUPLEX_FULL) {
-- 
2.17.1

[PATCH net-next 3/5] net: gemini: Allow multiple ports to instantiate

[Linus Walleij]

The code was not tested with two ports actually in use at
the same time. (I blame this on lack of actual hardware using
that feature.) Now after locating a system using both ports,
add necessary fix to make both ports come up.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index b49ed8964026..8d192fcd51c8 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -1787,7 +1787,10 @@ static int gmac_open(struct net_device *netdev)
 	phy_start(netdev->phydev);
 
 	err = geth_resize_freeq(port);
-	if (err) {
+	/* It's fine if it's just busy, the other port has set up
+	 * the freeq in that case.
+	 */
+	if (err && (err != -EBUSY)) {
 		netdev_err(netdev, "could not resize freeq\n");
 		goto err_stop_phy;
 	}
-- 
2.17.1

[PATCH net-next 3/5] net: gemini: Allow multiple ports to instantiate

[Linus Walleij]

The code was not tested with two ports actually in use at
the same time. (I blame this on lack of actual hardware using
that feature.) Now after locating a system using both ports,
add necessary fix to make both ports come up.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index b49ed8964026..8d192fcd51c8 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -1787,7 +1787,10 @@ static int gmac_open(struct net_device *netdev)
 	phy_start(netdev->phydev);
 
 	err = geth_resize_freeq(port);
-	if (err) {
+	/* It's fine if it's just busy, the other port has set up
+	 * the freeq in that case.
+	 */
+	if (err && (err != -EBUSY)) {
 		netdev_err(netdev, "could not resize freeq\n");
 		goto err_stop_phy;
 	}
-- 
2.17.1

[PATCH net-next 4/5] net: gemini: Move main init to port

[Linus Walleij]

The initialization sequence for the ethernet, setting up
interrupt routing and such things, need to be done after
both the ports are clocked and reset. Before this the
config will not "take". Move the initialization to the
port probe function and keep track of init status in
the state.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 8d192fcd51c8..79324bbfd768 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -146,6 +146,7 @@ struct gemini_ethernet {
 	void __iomem *base;
 	struct gemini_ethernet_port *port0;
 	struct gemini_ethernet_port *port1;
+	bool initialized;
 
 	spinlock_t	irq_lock; /* Locks IRQ-related registers */
 	unsigned int	freeq_order;
@@ -2301,6 +2302,14 @@ static void gemini_port_remove(struct gemini_ethernet_port *port)
 
 static void gemini_ethernet_init(struct gemini_ethernet *geth)
 {
+	/* Only do this once both ports are online */
+	if (geth->initialized)
+		return;
+	if (geth->port0 && geth->port1)
+		geth->initialized = true;
+	else
+		return;
+
 	writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);
 	writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);
 	writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_2_REG);
@@ -2447,6 +2456,10 @@ static int gemini_ethernet_port_probe(struct platform_device *pdev)
 		geth->port0 = port;
 	else
 		geth->port1 = port;
+
+	/* This will just be done once both ports are up and reset */
+	gemini_ethernet_init(geth);
+
 	platform_set_drvdata(pdev, port);
 
 	/* Set up and register the netdev */
@@ -2564,7 +2577,6 @@ static int gemini_ethernet_probe(struct platform_device *pdev)
 
 	spin_lock_init(&geth->irq_lock);
 	spin_lock_init(&geth->freeq_lock);
-	gemini_ethernet_init(geth);
 
 	/* The children will use this */
 	platform_set_drvdata(pdev, geth);
@@ -2577,8 +2589,8 @@ static int gemini_ethernet_remove(struct platform_device *pdev)
 {
 	struct gemini_ethernet *geth = platform_get_drvdata(pdev);
 
-	gemini_ethernet_init(geth);
 	geth_cleanup_freeq(geth);
+	geth->initialized = false;
 
 	return 0;
 }
-- 
2.17.1

[PATCH net-next 4/5] net: gemini: Move main init to port

[Linus Walleij]

The initialization sequence for the ethernet, setting up
interrupt routing and such things, need to be done after
both the ports are clocked and reset. Before this the
config will not "take". Move the initialization to the
port probe function and keep track of init status in
the state.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 8d192fcd51c8..79324bbfd768 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -146,6 +146,7 @@ struct gemini_ethernet {
 	void __iomem *base;
 	struct gemini_ethernet_port *port0;
 	struct gemini_ethernet_port *port1;
+	bool initialized;
 
 	spinlock_t	irq_lock; /* Locks IRQ-related registers */
 	unsigned int	freeq_order;
@@ -2301,6 +2302,14 @@ static void gemini_port_remove(struct gemini_ethernet_port *port)
 
 static void gemini_ethernet_init(struct gemini_ethernet *geth)
 {
+	/* Only do this once both ports are online */
+	if (geth->initialized)
+		return;
+	if (geth->port0 && geth->port1)
+		geth->initialized = true;
+	else
+		return;
+
 	writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_0_REG);
 	writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_1_REG);
 	writel(0, geth->base + GLOBAL_INTERRUPT_ENABLE_2_REG);
@@ -2447,6 +2456,10 @@ static int gemini_ethernet_port_probe(struct platform_device *pdev)
 		geth->port0 = port;
 	else
 		geth->port1 = port;
+
+	/* This will just be done once both ports are up and reset */
+	gemini_ethernet_init(geth);
+
 	platform_set_drvdata(pdev, port);
 
 	/* Set up and register the netdev */
@@ -2564,7 +2577,6 @@ static int gemini_ethernet_probe(struct platform_device *pdev)
 
 	spin_lock_init(&geth->irq_lock);
 	spin_lock_init(&geth->freeq_lock);
-	gemini_ethernet_init(geth);
 
 	/* The children will use this */
 	platform_set_drvdata(pdev, geth);
@@ -2577,8 +2589,8 @@ static int gemini_ethernet_remove(struct platform_device *pdev)
 {
 	struct gemini_ethernet *geth = platform_get_drvdata(pdev);
 
-	gemini_ethernet_init(geth);
 	geth_cleanup_freeq(geth);
+	geth->initialized = false;
 
 	return 0;
 }
-- 
2.17.1

[PATCH net-next 5/5] net: gemini: Indicate that we can handle jumboframes

[Linus Walleij]

The hardware supposedly handles frames up to 10236 bytes and
implements .ndo_change_mtu() so accept 10236 minus the ethernet
header for a VLAN tagged frame on the netdevices.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 79324bbfd768..ae475393e4ac 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -2473,6 +2473,11 @@ static int gemini_ethernet_port_probe(struct platform_device *pdev)
 
 	netdev->hw_features = GMAC_OFFLOAD_FEATURES;
 	netdev->features |= GMAC_OFFLOAD_FEATURES | NETIF_F_GRO;
+	/* We can handle jumbo frames up to 10236 bytes so, let's accept
+	 * payloads of 10236 bytes minus VLAN and ethernet header
+	 */
+	netdev->min_mtu = 256;
+	netdev->max_mtu = 10236 - VLAN_ETH_HLEN;
 
 	port->freeq_refill = 0;
 	netif_napi_add(netdev, &port->napi, gmac_napi_poll,
-- 
2.17.1

[PATCH net-next 5/5] net: gemini: Indicate that we can handle jumboframes

[Linus Walleij]

The hardware supposedly handles frames up to 10236 bytes and
implements .ndo_change_mtu() so accept 10236 minus the ethernet
header for a VLAN tagged frame on the netdevices.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/net/ethernet/cortina/gemini.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
index 79324bbfd768..ae475393e4ac 100644
--- a/drivers/net/ethernet/cortina/gemini.c
+++ b/drivers/net/ethernet/cortina/gemini.c
@@ -2473,6 +2473,11 @@ static int gemini_ethernet_port_probe(struct platform_device *pdev)
 
 	netdev->hw_features = GMAC_OFFLOAD_FEATURES;
 	netdev->features |= GMAC_OFFLOAD_FEATURES | NETIF_F_GRO;
+	/* We can handle jumbo frames up to 10236 bytes so, let's accept
+	 * payloads of 10236 bytes minus VLAN and ethernet header
+	 */
+	netdev->min_mtu = 256;
+	netdev->max_mtu = 10236 - VLAN_ETH_HLEN;
 
 	port->freeq_refill = 0;
 	netif_napi_add(netdev, &port->napi, gmac_napi_poll,
-- 
2.17.1

Re: [PATCH net-next 2/5] net: gemini: Improve connection prints

[Andrew Lunn]

On Sat, Jun 30, 2018 at 06:18:03PM +0200, Linus Walleij wrote:
> Instead of just specify that a PHY is connected at some
> speed, also specify which one. This is helpful with several
> PHYs on the system.

Hi Linus

Could you just use phy_print_status()

      Andrew

[PATCH net-next 2/5] net: gemini: Improve connection prints

[Andrew Lunn]

On Sat, Jun 30, 2018 at 06:18:03PM +0200, Linus Walleij wrote:
> Instead of just specify that a PHY is connected at some
> speed, also specify which one. This is helpful with several
> PHYs on the system.

Hi Linus

Could you just use phy_print_status()

      Andrew

Re: [PATCH net-next 5/5] net: gemini: Indicate that we can handle jumboframes

[Andrew Lunn]

On Sat, Jun 30, 2018 at 06:18:06PM +0200, Linus Walleij wrote:
> The hardware supposedly handles frames up to 10236 bytes and
> implements .ndo_change_mtu() so accept 10236 minus the ethernet
> header for a VLAN tagged frame on the netdevices.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  drivers/net/ethernet/cortina/gemini.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
> index 79324bbfd768..ae475393e4ac 100644
> --- a/drivers/net/ethernet/cortina/gemini.c
> +++ b/drivers/net/ethernet/cortina/gemini.c
> @@ -2473,6 +2473,11 @@ static int gemini_ethernet_port_probe(struct platform_device *pdev)
>  
>  	netdev->hw_features = GMAC_OFFLOAD_FEATURES;
>  	netdev->features |= GMAC_OFFLOAD_FEATURES | NETIF_F_GRO;
> +	/* We can handle jumbo frames up to 10236 bytes so, let's accept
> +	 * payloads of 10236 bytes minus VLAN and ethernet header
> +	 */
> +	netdev->min_mtu = 256;
> +	netdev->max_mtu = 10236 - VLAN_ETH_HLEN;

Hi Linus

The commit message does not mention the min mtu you set here. Where
does 256 come from?

Thanks
     Andrew

[PATCH net-next 5/5] net: gemini: Indicate that we can handle jumboframes

[Andrew Lunn]

On Sat, Jun 30, 2018 at 06:18:06PM +0200, Linus Walleij wrote:
> The hardware supposedly handles frames up to 10236 bytes and
> implements .ndo_change_mtu() so accept 10236 minus the ethernet
> header for a VLAN tagged frame on the netdevices.
> 
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  drivers/net/ethernet/cortina/gemini.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c
> index 79324bbfd768..ae475393e4ac 100644
> --- a/drivers/net/ethernet/cortina/gemini.c
> +++ b/drivers/net/ethernet/cortina/gemini.c
> @@ -2473,6 +2473,11 @@ static int gemini_ethernet_port_probe(struct platform_device *pdev)
>  
>  	netdev->hw_features = GMAC_OFFLOAD_FEATURES;
>  	netdev->features |= GMAC_OFFLOAD_FEATURES | NETIF_F_GRO;
> +	/* We can handle jumbo frames up to 10236 bytes so, let's accept
> +	 * payloads of 10236 bytes minus VLAN and ethernet header
> +	 */
> +	netdev->min_mtu = 256;
> +	netdev->max_mtu = 10236 - VLAN_ETH_HLEN;

Hi Linus

The commit message does not mention the min mtu you set here. Where
does 256 come from?

Thanks
     Andrew