| Message ID | 20220221084328.3661250-1-o.rempel@pengutronix.de (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v1,1/1] net: dsa: microchip: ksz9477: implement MTU configuration | expand |
On Mon, 21 Feb 2022 09:43:28 +0100 Oleksij Rempel wrote: > This chips supports two ways to configure max MTU size: > - by setting SW_LEGAL_PACKET_DISABLE bit: if this bit is 0 allowed packed size > will be between 64 and bytes 1518. If this bit is 1, it will accept > packets up to 2000 bytes. > - by setting SW_JUMBO_PACKET bit. If this bit is set, the chip will > ignore SW_LEGAL_PACKET_DISABLE value and use REG_SW_MTU__2 register to > configure MTU size. > > Current driver has disabled SW_JUMBO_PACKET bit and activates > SW_LEGAL_PACKET_DISABLE. So the switch will pass all packets up to 2000 without > any way to configure it. > > By providing port_change_mtu we are switch to SW_JUMBO_PACKET way and will > be able to configure MTU up to ~9000. And it has no negative side affects to always have jumbo enabled? Maybe the internal buffer will be carved up in a different way? > +static int ksz9477_change_mtu(struct dsa_switch *ds, int port, int mtu) > +{ > + struct ksz_device *dev = ds->priv; > + u16 new_mtu, max_mtu = 0; > + int i; > + > + new_mtu = mtu + ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN; > + > + if (dsa_is_cpu_port(ds, port)) > + new_mtu += KSZ9477_INGRESS_TAG_LEN; > + > + /* Cache the per-port MTU setting */ > + dev->ports[port].max_mtu = new_mtu; > + > + for (i = 0; i < dev->port_cnt; i++) { > + if (dev->ports[i].max_mtu > max_mtu) > + max_mtu = dev->ports[i].max_mtu; > + } nit: for (...) max_mtu = max(max_mtu, dev->ports[i].max_mtu) > @@ -41,6 +41,7 @@ struct ksz_port { > > struct ksz_port_mib mib; > phy_interface_t interface; > + unsigned int max_mtu; > }; max_mtu already has two meanings in this patch, let's call this max_frame or max_len etc, instead of adding a third meaning.
On Tue, Feb 22, 2022 at 04:52:17PM -0800, Jakub Kicinski wrote: > On Mon, 21 Feb 2022 09:43:28 +0100 Oleksij Rempel wrote: > > This chips supports two ways to configure max MTU size: > > - by setting SW_LEGAL_PACKET_DISABLE bit: if this bit is 0 allowed packed size > > will be between 64 and bytes 1518. If this bit is 1, it will accept > > packets up to 2000 bytes. > > - by setting SW_JUMBO_PACKET bit. If this bit is set, the chip will > > ignore SW_LEGAL_PACKET_DISABLE value and use REG_SW_MTU__2 register to > > configure MTU size. > > > > Current driver has disabled SW_JUMBO_PACKET bit and activates > > SW_LEGAL_PACKET_DISABLE. So the switch will pass all packets up to 2000 without > > any way to configure it. > > > > By providing port_change_mtu we are switch to SW_JUMBO_PACKET way and will > > be able to configure MTU up to ~9000. > > And it has no negative side affects to always have jumbo enabled? > Maybe the internal buffer will be carved up in a different way? Hm I tested it with iperf3 on 4 of 7 ports on this switch without noticeable changes before and after this patch. My setup looks as following: ----` | /- iperf -s = port0 | \- iperf3 -c 172.17.0.11 -t 100 | | = port1 ... same as port0, ... -c 172.17.0.10 = port2 ... same as port0, ... -c 172.17.0.13 = port3 ... same as port0, ... -c 172.17.0.12 Each port was sending and receiving. Each instance reported 938 Mbits/sec > > +static int ksz9477_change_mtu(struct dsa_switch *ds, int port, int mtu) > > +{ > > + struct ksz_device *dev = ds->priv; > > + u16 new_mtu, max_mtu = 0; > > + int i; > > + > > + new_mtu = mtu + ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN; > > + > > + if (dsa_is_cpu_port(ds, port)) > > + new_mtu += KSZ9477_INGRESS_TAG_LEN; > > + > > + /* Cache the per-port MTU setting */ > > + dev->ports[port].max_mtu = new_mtu; > > + > > + for (i = 0; i < dev->port_cnt; i++) { > > + if (dev->ports[i].max_mtu > max_mtu) > > + max_mtu = dev->ports[i].max_mtu; > > + } > > nit: > > for (...) > max_mtu = max(max_mtu, dev->ports[i].max_mtu) > > > @@ -41,6 +41,7 @@ struct ksz_port { > > > > struct ksz_port_mib mib; > > phy_interface_t interface; > > + unsigned int max_mtu; > > }; > > max_mtu already has two meanings in this patch, let's call this > max_frame or max_len etc, instead of adding a third meaning. Ok, thx. Will update the patch. Regards, Oleksij
diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c index 18ffc8ded7ee..ae5ce7e71d4c 100644 --- a/drivers/net/dsa/microchip/ksz9477.c +++ b/drivers/net/dsa/microchip/ksz9477.c @@ -11,6 +11,7 @@ #include <linux/platform_data/microchip-ksz.h> #include <linux/phy.h> #include <linux/if_bridge.h> +#include <linux/if_vlan.h> #include <net/dsa.h> #include <net/switchdev.h> @@ -182,6 +183,35 @@ static void ksz9477_port_cfg32(struct ksz_device *dev, int port, int offset, bits, set ? bits : 0); } +static int ksz9477_change_mtu(struct dsa_switch *ds, int port, int mtu) +{ + struct ksz_device *dev = ds->priv; + u16 new_mtu, max_mtu = 0; + int i; + + new_mtu = mtu + ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN; + + if (dsa_is_cpu_port(ds, port)) + new_mtu += KSZ9477_INGRESS_TAG_LEN; + + /* Cache the per-port MTU setting */ + dev->ports[port].max_mtu = new_mtu; + + for (i = 0; i < dev->port_cnt; i++) { + if (dev->ports[i].max_mtu > max_mtu) + max_mtu = dev->ports[i].max_mtu; + } + + return regmap_update_bits(dev->regmap[1], REG_SW_MTU__2, + REG_SW_MTU_MASK, max_mtu); +} + +static int ksz9477_max_mtu(struct dsa_switch *ds, int port) +{ + return KSZ9477_MAX_MTU - ETH_HLEN - ETH_FCS_LEN - VLAN_HLEN - + KSZ9477_INGRESS_TAG_LEN; +} + static int ksz9477_wait_vlan_ctrl_ready(struct ksz_device *dev) { unsigned int val; @@ -1412,8 +1442,14 @@ static int ksz9477_setup(struct dsa_switch *ds) /* Do not work correctly with tail tagging. */ ksz_cfg(dev, REG_SW_MAC_CTRL_0, SW_CHECK_LENGTH, false); - /* accept packet up to 2000bytes */ - ksz_cfg(dev, REG_SW_MAC_CTRL_1, SW_LEGAL_PACKET_DISABLE, true); + /* Enable REG_SW_MTU__2 reg by setting SW_JUMBO_PACKET */ + ksz_cfg(dev, REG_SW_MAC_CTRL_1, SW_JUMBO_PACKET, true); + + /* Now we can configure default MTU value */ + ret = regmap_update_bits(dev->regmap[1], REG_SW_MTU__2, REG_SW_MTU_MASK, + VLAN_ETH_FRAME_LEN + ETH_FCS_LEN); + if (ret) + return ret; ksz9477_config_cpu_port(ds); @@ -1460,6 +1496,8 @@ static const struct dsa_switch_ops ksz9477_switch_ops = { .port_mirror_add = ksz9477_port_mirror_add, .port_mirror_del = ksz9477_port_mirror_del, .get_stats64 = ksz9477_get_stats64, + .port_change_mtu = ksz9477_change_mtu, + .port_max_mtu = ksz9477_max_mtu, }; static u32 ksz9477_get_port_addr(int port, int offset) diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h b/drivers/net/dsa/microchip/ksz9477_reg.h index 16939f29faa5..34c368d3676c 100644 --- a/drivers/net/dsa/microchip/ksz9477_reg.h +++ b/drivers/net/dsa/microchip/ksz9477_reg.h @@ -176,6 +176,7 @@ #define REG_SW_MAC_ADDR_5 0x0307 #define REG_SW_MTU__2 0x0308 +#define REG_SW_MTU_MASK GENMASK(13, 0) #define REG_SW_ISP_TPID__2 0x030A @@ -1662,4 +1663,7 @@ /* 148,800 frames * 67 ms / 100 */ #define BROADCAST_STORM_VALUE 9969 +#define KSZ9477_INGRESS_TAG_LEN 2 +#define KSZ9477_MAX_MTU 9000 + #endif /* KSZ9477_REGS_H */ diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h index c6fa487fb006..edf4a442de57 100644 --- a/drivers/net/dsa/microchip/ksz_common.h +++ b/drivers/net/dsa/microchip/ksz_common.h @@ -41,6 +41,7 @@ struct ksz_port { struct ksz_port_mib mib; phy_interface_t interface; + unsigned int max_mtu; }; struct ksz_device {
This chips supports two ways to configure max MTU size: - by setting SW_LEGAL_PACKET_DISABLE bit: if this bit is 0 allowed packed size will be between 64 and bytes 1518. If this bit is 1, it will accept packets up to 2000 bytes. - by setting SW_JUMBO_PACKET bit. If this bit is set, the chip will ignore SW_LEGAL_PACKET_DISABLE value and use REG_SW_MTU__2 register to configure MTU size. Current driver has disabled SW_JUMBO_PACKET bit and activates SW_LEGAL_PACKET_DISABLE. So the switch will pass all packets up to 2000 without any way to configure it. By providing port_change_mtu we are switch to SW_JUMBO_PACKET way and will be able to configure MTU up to ~9000. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> --- drivers/net/dsa/microchip/ksz9477.c | 42 +++++++++++++++++++++++-- drivers/net/dsa/microchip/ksz9477_reg.h | 4 +++ drivers/net/dsa/microchip/ksz_common.h | 1 + 3 files changed, 45 insertions(+), 2 deletions(-)