diff mbox series

[net-next] net: dsa: lantiq_gswip: enable jumbo frames on GSWIP

Message ID 20220308230457.1599237-1-olek2@wp.pl (mailing list archive)
State Accepted
Commit c40bb4fedcd6b8b6a714da5dd466eb88ed2652d1
Delegated to: Netdev Maintainers
Headers show
Series [net-next] net: dsa: lantiq_gswip: enable jumbo frames on GSWIP | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
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
netdev/cc_maintainers success CCed 9 of 9 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 83 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Aleksander Jan Bajkowski March 8, 2022, 11:04 p.m. UTC 
This enables non-standard MTUs on a per-port basis, with the overall
frame size set based on the CPU port.

When the MTU is not changed, this should have no effect.

Long packets crash the switch with MTUs of greater than 2526, so the
maximum is limited for now. Medium packets are sometimes dropped (e.g.
TCP over 2477, UDP over 2516-2519, ICMP over 2526), Hence an MTU value
of 2400 seems safe.

Signed-off-by: Thomas Nixon <tom@tomn.co.uk>
Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
---
 drivers/net/dsa/lantiq_gswip.c | 53 +++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 4 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org March 11, 2022, 4:30 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Wed,  9 Mar 2022 00:04:57 +0100 you wrote:
> This enables non-standard MTUs on a per-port basis, with the overall
> frame size set based on the CPU port.
> 
> When the MTU is not changed, this should have no effect.
> 
> Long packets crash the switch with MTUs of greater than 2526, so the
> maximum is limited for now. Medium packets are sometimes dropped (e.g.
> TCP over 2477, UDP over 2516-2519, ICMP over 2526), Hence an MTU value
> of 2400 seems safe.
> 
> [...]

Here is the summary with links:
  - [net-next] net: dsa: lantiq_gswip: enable jumbo frames on GSWIP
    https://git.kernel.org/netdev/net-next/c/c40bb4fedcd6

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c
index 8a7a8093a156..f7059ab3b014 100644
--- a/drivers/net/dsa/lantiq_gswip.c
+++ b/drivers/net/dsa/lantiq_gswip.c
@@ -213,6 +213,7 @@ 
 #define  GSWIP_MAC_CTRL_0_GMII_MII	0x0001
 #define  GSWIP_MAC_CTRL_0_GMII_RGMII	0x0002
 #define GSWIP_MAC_CTRL_2p(p)		(0x905 + ((p) * 0xC))
+#define GSWIP_MAC_CTRL_2_LCHKL		BIT(2) /* Frame Length Check Long Enable */
 #define GSWIP_MAC_CTRL_2_MLEN		BIT(3) /* Maximum Untagged Frame Lnegth */
 
 /* Ethernet Switch Fetch DMA Port Control Register */
@@ -239,6 +240,15 @@ 
 
 #define XRX200_GPHY_FW_ALIGN	(16 * 1024)
 
+/* Maximum packet size supported by the switch. In theory this should be 10240,
+ * but long packets currently cause lock-ups with an MTU of over 2526. Medium
+ * packets are sometimes dropped (e.g. TCP over 2477, UDP over 2516-2519, ICMP
+ * over 2526), hence an MTU value of 2400 seems safe. This issue only affects
+ * packet reception. This is probably caused by the PPA engine, which is on the
+ * RX part of the device. Packet transmission works properly up to 10240.
+ */
+#define GSWIP_MAX_PACKET_LENGTH	2400
+
 struct gswip_hw_info {
 	int max_ports;
 	int cpu_port;
@@ -863,10 +873,6 @@  static int gswip_setup(struct dsa_switch *ds)
 	gswip_switch_mask(priv, 0, GSWIP_PCE_PCTRL_0_INGRESS,
 			  GSWIP_PCE_PCTRL_0p(cpu_port));
 
-	gswip_switch_mask(priv, 0, GSWIP_MAC_CTRL_2_MLEN,
-			  GSWIP_MAC_CTRL_2p(cpu_port));
-	gswip_switch_w(priv, VLAN_ETH_FRAME_LEN + 8 + ETH_FCS_LEN,
-		       GSWIP_MAC_FLEN);
 	gswip_switch_mask(priv, 0, GSWIP_BM_QUEUE_GCTRL_GL_MOD,
 			  GSWIP_BM_QUEUE_GCTRL);
 
@@ -883,6 +889,8 @@  static int gswip_setup(struct dsa_switch *ds)
 		return err;
 	}
 
+	ds->mtu_enforcement_ingress = true;
+
 	gswip_port_enable(ds, cpu_port, NULL);
 
 	ds->configure_vlan_while_not_filtering = false;
@@ -1446,6 +1454,39 @@  static int gswip_port_fdb_dump(struct dsa_switch *ds, int port,
 	return 0;
 }
 
+static int gswip_port_max_mtu(struct dsa_switch *ds, int port)
+{
+	/* Includes 8 bytes for special header. */
+	return GSWIP_MAX_PACKET_LENGTH - VLAN_ETH_HLEN - ETH_FCS_LEN;
+}
+
+static int gswip_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
+{
+	struct gswip_priv *priv = ds->priv;
+	int cpu_port = priv->hw_info->cpu_port;
+
+	/* CPU port always has maximum mtu of user ports, so use it to set
+	 * switch frame size, including 8 byte special header.
+	 */
+	if (port == cpu_port) {
+		new_mtu += 8;
+		gswip_switch_w(priv, VLAN_ETH_HLEN + new_mtu + ETH_FCS_LEN,
+			       GSWIP_MAC_FLEN);
+	}
+
+	/* Enable MLEN for ports with non-standard MTUs, including the special
+	 * header on the CPU port added above.
+	 */
+	if (new_mtu != ETH_DATA_LEN)
+		gswip_switch_mask(priv, 0, GSWIP_MAC_CTRL_2_MLEN,
+				  GSWIP_MAC_CTRL_2p(port));
+	else
+		gswip_switch_mask(priv, GSWIP_MAC_CTRL_2_MLEN, 0,
+				  GSWIP_MAC_CTRL_2p(port));
+
+	return 0;
+}
+
 static void gswip_xrx200_phylink_get_caps(struct dsa_switch *ds, int port,
 					  struct phylink_config *config)
 {
@@ -1791,6 +1832,8 @@  static const struct dsa_switch_ops gswip_xrx200_switch_ops = {
 	.port_fdb_add		= gswip_port_fdb_add,
 	.port_fdb_del		= gswip_port_fdb_del,
 	.port_fdb_dump		= gswip_port_fdb_dump,
+	.port_change_mtu	= gswip_port_change_mtu,
+	.port_max_mtu		= gswip_port_max_mtu,
 	.phylink_get_caps	= gswip_xrx200_phylink_get_caps,
 	.phylink_mac_config	= gswip_phylink_mac_config,
 	.phylink_mac_link_down	= gswip_phylink_mac_link_down,
@@ -1815,6 +1858,8 @@  static const struct dsa_switch_ops gswip_xrx300_switch_ops = {
 	.port_fdb_add		= gswip_port_fdb_add,
 	.port_fdb_del		= gswip_port_fdb_del,
 	.port_fdb_dump		= gswip_port_fdb_dump,
+	.port_change_mtu	= gswip_port_change_mtu,
+	.port_max_mtu		= gswip_port_max_mtu,
 	.phylink_get_caps	= gswip_xrx300_phylink_get_caps,
 	.phylink_mac_config	= gswip_phylink_mac_config,
 	.phylink_mac_link_down	= gswip_phylink_mac_link_down,