RE: [PATCH v6 net-next 15/15] net: dsa: netc: add support for ethtool private statistics

> commit 66f17e671c095a381aeff77d1d8c0cae1e43722c
> Author: Wei Fang <[email protected]>
> 
> net: dsa: netc: add support for ethtool private statistics
> 
> Implement the ethtool private statistics interface to expose additional
> port-level and MAC-level counters that are not covered by the standard
> IEEE 802.3 statistics. The pMAC counters are only reported when the port
> supports Frame Preemption (802.1Qbu/802.3br).
> 
> > diff --git a/drivers/net/dsa/netc/netc_ethtool.c
> b/drivers/net/dsa/netc/netc_ethtool.c
> > index ac8940b5a85c6..8d04db534347c 100644
> > --- a/drivers/net/dsa/netc/netc_ethtool.c
> > +++ b/drivers/net/dsa/netc/netc_ethtool.c
> > @@ -19,6 +19,56 @@ static const struct ethtool_rmon_hist_range
> netc_rmon_ranges[] = {
> >  	{ }
> >  };
> >
> > +static const struct netc_port_stat netc_port_counters[] = {
> > +	{ NETC_PTGSLACR,	"port gate late arrival frames" },
> > +	{ NETC_PSDFTCR,	"port SDF transmit frames" },
> > +	{ NETC_PSDFDDCR,	"port SDF drop duplicate frames" },
> > +	{ NETC_PRXDCR,		"port rx discard frames" },
> > +	{ NETC_PRXDCRRR,	"port rx discard read-reset" },
> > +	{ NETC_PRXDCRR0,	"port rx discard reason 0" },
> > +	{ NETC_PRXDCRR1,	"port rx discard reason 1" },
> > +	{ NETC_PTXDCR,		"port tx discard frames" },
> > +	{ NETC_PTXDCRRR,	"port tx discard read-reset" },
> > +	{ NETC_PTXDCRR0,	"port tx discard reason 0" },
> > +	{ NETC_PTXDCRR1,	"port tx discard reason 1" },
> > +	{ NETC_BPDCR,		"bridge port discard frames" },
> > +	{ NETC_BPDCRRR,	"bridge port discard read-reset" },
> > +	{ NETC_BPDCRR0,	"bridge port discard reason 0" },
> > +	{ NETC_BPDCRR1,	"bridge port discard reason 1" },
> > +};
> > +
> > +static const struct netc_port_stat netc_emac_counters[] = {
> > +	{ NETC_PM_ROCT(0),	"eMAC rx octets" },
> > +	{ NETC_PM_RVLAN(0),	"eMAC rx VLAN frames" },
> > +	{ NETC_PM_RERR(0),	"eMAC rx frame errors" },
> > +	{ NETC_PM_RUCA(0),	"eMAC rx unicast frames" },
> > +	{ NETC_PM_RDRP(0),	"eMAC rx dropped packets" },
> > +	{ NETC_PM_RPKT(0),	"eMAC rx packets" },
> > +	{ NETC_PM_TOCT(0),	"eMAC tx octets" },
> > +	{ NETC_PM_TVLAN(0),	"eMAC tx VLAN frames" },
> > +	{ NETC_PM_TFCS(0),	"eMAC tx FCS errors" },
> > +	{ NETC_PM_TUCA(0),	"eMAC tx unicast frames" },
> > +	{ NETC_PM_TPKT(0),	"eMAC tx packets" },
> > +	{ NETC_PM_TUND(0),	"eMAC tx undersized packets" },
> > +	{ NETC_PM_TIOCT(0),	"eMAC tx invalid octets" },
> > +};
> > +
> > +static const struct netc_port_stat netc_pmac_counters[] = {
> > +	{ NETC_PM_ROCT(1),	"pMAC rx octets" },
> > +	{ NETC_PM_RVLAN(1),	"pMAC rx VLAN frames" },
> > +	{ NETC_PM_RERR(1),	"pMAC rx frame errors" },
> > +	{ NETC_PM_RUCA(1),	"pMAC rx unicast frames" },
> > +	{ NETC_PM_RDRP(1),	"pMAC rx dropped packets" },
> > +	{ NETC_PM_RPKT(1),	"pMAC rx packets" },
> > +	{ NETC_PM_TOCT(1),	"pMAC tx octets" },
> > +	{ NETC_PM_TVLAN(1),	"pMAC tx VLAN frames" },
> > +	{ NETC_PM_TFCS(1),	"pMAC tx FCS errors" },
> > +	{ NETC_PM_TUCA(1),	"pMAC tx unicast frames" },
> > +	{ NETC_PM_TPKT(1),	"pMAC tx packets" },
> > +	{ NETC_PM_TUND(1),	"pMAC tx undersized packets" },
> > +	{ NETC_PM_TIOCT(1),	"pMAC tx invalid octets" },
> > +};
> 
> Should these standard MAC statistics be exposed as private ethtool strings?
> 
> Many of the counters defined in netc_emac_counters and netc_pmac_counters,
> such as rx octets, rx packets, rx dropped packets, and tx FCS errors,
> appear to correspond directly to existing standard uAPIs like
> struct rtnl_link_stats64 or struct ethtool_eth_mac_stats.
> 
> Since the driver already implements netc_port_get_eth_mac_stats(), which
> supports both eMAC and pMAC sources, could these standard counters be
> reported through the standard interfaces instead to avoid duplicating
> them in ethtool -S?
> 

For the NETC switch, its ports support preemption, so each port has two MACs
(express MAC and preemptive MAC). The driver-private statistics can help users
obtain statistics for each MAC, just like the standard statistics of ethtool.
However, rtnl_link_stats64 retrieves the combined statistics of the two MACs.

In addition, ethtool_eth_mac_stats only has the FCS error counter for RX,
not TX. what I added to driver-private was TX's FCS error counter.

Please ignore this warning.