RE: [PATCH net-next] net: stmmac: xgmac3+: add FPE handshaking support

[Jianheng Zhang]

Hi Vladimir,

> -----Original Message-----
> From: Vladimir Oltean <olteanv@xxxxxxxxx>
> Sent: Monday, December 11, 2023 9:40 PM
> To: Jianheng Zhang <jianheng@xxxxxxxxxxxx>
> Cc: Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx>; Jose Abreu <joabreu@xxxxxxxxxxxx>; David S.
> Miller <davem@xxxxxxxxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski
> <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; Maxime Coquelin
> <mcoquelin.stm32@xxxxxxxxx>; open list:STMMAC ETHERNET DRIVER <netdev@xxxxxxxxxxxxxxx>;
> moderated list:ARM/STM32 ARCHITECTURE <linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>;
> moderated list:ARM/STM32 ARCHITECTURE <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx>; open list
> <linux-kernel@xxxxxxxxxxxxxxx>; James Li <lijames@xxxxxxxxxxxx>; Martin McKenny
> <mmckenny@xxxxxxxxxxxx>
> Subject: Re: [PATCH net-next] net: stmmac: xgmac3+: add FPE handshaking support
> 
> Hi Jianheng,
> 
> On Mon, Dec 11, 2023 at 06:13:21AM +0000, Jianheng Zhang wrote:
> > Adds the HW specific support for Frame Preemption handshaking on XGMAC3+
> > cores.
> >
> > Signed-off-by: Jianheng Zhang <Jianheng.Zhang@xxxxxxxxxxxx>
> > ---
> 
> It's nice to see contributions from Synopsys!
> 
> Have you seen the (relatively newly introduced) common framework for
> Frame Preemption and the MAC Merge layer?
> https://urldefense.com/v3/__https://docs.kernel.org/networking/ethtool-netlink.html*mm-get__;Iw!!A
> 4F2R9G_pg!Z461fiVMBqXVlpgdD8t9ey1qGp6_hZg9jNlY__TljPgVHZcYbqtzqQhbI9IpjDoHBoOCX14vZOf2J
> hZgsW_fnQ$
> https://urldefense.com/v3/__https://man7.org/linux/man-pages/man8/ethtool.8.html__;!!A4F2R9G_pg
> !Z461fiVMBqXVlpgdD8t9ey1qGp6_hZg9jNlY__TljPgVHZcYbqtzqQhbI9IpjDoHBoOCX14vZOf2JhbkJXuqTA$
> https://urldefense.com/v3/__https://man7.org/linux/man-pages/man8/tc-mqprio.8.html__;!!A4F2R9G_
> pg!Z461fiVMBqXVlpgdD8t9ey1qGp6_hZg9jNlY__TljPgVHZcYbqtzqQhbI9IpjDoHBoOCX14vZOf2JhbEBQbq
> ZQ$  # "fp" option
> https://urldefense.com/v3/__https://man7.org/linux/man-pages/man8/tc-taprio.8.html__;!!A4F2R9G_p
> g!Z461fiVMBqXVlpgdD8t9ey1qGp6_hZg9jNlY__TljPgVHZcYbqtzqQhbI9IpjDoHBoOCX14vZOf2JhbOMeXO
> UQ$  # "fp" option
> 
> I think it would be valuable if the stmmac driver would also use it, so
> it could support openlldp and pass the selftest at
> https://urldefense.com/v3/__https://github.com/torvalds/linux/blob/master/tools/testing/selftests/net/f
> orwarding/ethtool_mm.sh__;!!A4F2R9G_pg!Z461fiVMBqXVlpgdD8t9ey1qGp6_hZg9jNlY__TljPgVHZcYb
> qtzqQhbI9IpjDoHBoOCX14vZOf2JhasMiyt2w$

Thanks for mentioning the common framework for Frame Preemption and the MAC 
Merge layer. I think it is essential to let the stmmac driver support it next.
And it is also needed to avoid the code duplication mentioned by Serge.

Jianheng