Subject: Re: [PATCH v5 net-next 2/2] net: airoha: Introduce ethernet support for EN7581 SoC

From: Lorenzo Bianconi <[email-masked]>
Date: Sat, 6 Jul 2024 10:27:00 +0200

> On Thu, Jul 04, 2024 at 10:08:11AM +0200, Lorenzo Bianconi wrote:
> > Add airoha_eth driver in order to introduce ethernet support for
> > Airoha EN7581 SoC available on EN7581 development board (en7581-evb).
> > en7581-evb networking architecture is composed by airoha_eth as mac
> > controller (cpu port) and a mt7530 dsa based switch.
> > EN7581 mac controller is mainly composed by Frame Engine (FE) and
> > QoS-DMA (QDMA) modules. FE is used for traffic offloading (just basic
> > functionalities are supported now) while QDMA is used for DMA operation
> > and QOS functionalities between mac layer and the dsa switch (hw QoS is
> > not available yet and it will be added in the future).
> > Currently only hw lan features are available, hw wan will be added with
> > subsequent patches.
> > 
> > Tested-by: Benjamin Larsson <[email-masked]>
> > Signed-off-by: Lorenzo Bianconi <[email-masked]>
> 
> ...
> 
> > +static const char * const airoha_ethtool_stats_name[] = {
> > +	"tx_eth_pkt_cnt",
> > +	"tx_eth_byte_cnt",
> > +	"tx_ok_pkt_cnt",
> > +	"tx_ok_byte_cnt",
> > +	"tx_eth_drop_cnt",
> > +	"tx_eth_bc_cnt",
> > +	"tx_eth_mc_cnt",
> > +	"tx_eth_lt64_cnt",
> > +	"tx_eth_eq64_cnt",
> > +	"tx_eth_65_127_cnt",
> > +	"tx_eth_128_255_cnt",
> > +	"tx_eth_256_511_cnt",
> > +	"tx_eth_512_1023_cnt",
> > +	"tx_eth_1024_1518_cnt",
> > +	"tx_eth_gt1518_cnt",
> > +	"rx_eth_pkt_cnt",
> > +	"rx_eth_byte_cnt",
> > +	"rx_ok_pkt_cnt",
> > +	"rx_ok_byte_cnt",
> > +	"rx_eth_drop_cnt",
> > +	"rx_eth_bc_cnt",
> > +	"rx_eth_mc_cnt",
> > +	"rx_eth_crc_drop_cnt",
> > +	"rx_eth_frag_cnt",
> > +	"rx_eth_jabber_cnt",
> > +	"rx_eth_lt64_cnt",
> > +	"rx_eth_eq64_cnt",
> > +	"rx_eth_65_127_cnt",
> > +	"rx_eth_128_255_cnt",
> > +	"rx_eth_256_511_cnt",
> > +	"rx_eth_512_1023_cnt",
> > +	"rx_eth_1024_1518_cnt",
> > +	"rx_eth_gt1518_cnt",
> > +};
> 
> Hi Lorenzo,
> 
> Sorry for not noticing this earlier.

Hi Simon,

no worries :)

> It seems to me that some of the stats above could
> use standard stats, which is preferred.

Please correct me if I am wrong but it seems quite a common approach to have
same stats in both .ndo_get_stats64() and .get_ethtool_stats():
- https://github.com/torvalds/linux/blob/master/drivers/net/ethernet/mediatek/mtk_eth_soc.c#L212
- https://github.com/torvalds/linux/blob/master/drivers/net/ethernet/marvell/mvneta.c#L435
- https://github.com/torvalds/linux/blob/master/drivers/net/ethernet/intel/i40e/i40e_ethtool.c#L243
- https://github.com/torvalds/linux/blob/master/net/mac80211/ethtool.c#L52
- ...

Do you mean I should just report common stats (e.g. tx_packets or tx_bytes) in
.ndo_get_stats64()? Or it is fine to just add .ndo_get_stats64() callback (not
supported at the moment)?

> 
> Basically, my understanding is that one should:
> 1. Implement .ndo_get_stats64
>    (that seems relevant here)
> 2. As appropriate implement ethtool_stats non-extended stats operations
>    (perhaps not relevant here)

Can you please provide me a pointer for it?

Regards,
Lorenzo

> 3. Then implement get_ethtool_stats for what is left over
> 
> ...