Re: [PATCH net-next v2 6/8] ravb: Add net_features and net_hw_features to struct ravb_hw_info

From: Sergei Shtylyov <sergei.shtylyov@gmail.com>
To: Biju Das <biju.das.jz@bp.renesas.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
	Sergey Shtylyov <s.shtylyov@omprussia.ru>,
	Adam Ford <aford173@gmail.com>, Andrew Lunn <andrew@lunn.ch>,
	Yuusuke Ashizuka <ashiduka@fujitsu.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH net-next v2 6/8] ravb: Add net_features and net_hw_features to struct ravb_hw_info
Date: Fri, 6 Aug 2021 23:20:31 +0300	[thread overview]
Message-ID: <d038bed9-def6-9035-18fa-28ee527a149c@gmail.com> (raw)
In-Reply-To: <OS0PR01MB5922C5EE008113DEA3354BFA86F29@OS0PR01MB5922.jpnprd01.prod.outlook.com>

Hello!

On 8/5/21 10:18 PM, Biju Das wrote:

[...]
>>> On R-Car the checksum calculation on RX frames is done by the E-MAC
>>> module, whereas on RZ/G2L it is done by the TOE.
>>>
>>> TOE calculates the checksum of received frames from E-MAC and outputs
>>> it to DMAC. TOE also calculates the checksum of transmission frames
>>> from DMAC and outputs it E-MAC.
>>>
>>> Add net_features and net_hw_features to struct ravb_hw_info, to
>>> support subsequent SoCs without any code changes in the ravb_probe
>> function.
>>>
>>> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
>>> Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>>
>> [...]
>>> diff --git a/drivers/net/ethernet/renesas/ravb.h
>>> b/drivers/net/ethernet/renesas/ravb.h
>>> index b765b2b7d9e9..3df813b2e253 100644
>>> --- a/drivers/net/ethernet/renesas/ravb.h
>>> +++ b/drivers/net/ethernet/renesas/ravb.h
>>> @@ -991,6 +991,8 @@ enum ravb_chip_id {  struct ravb_hw_info {
>>>  	const char (*gstrings_stats)[ETH_GSTRING_LEN];
>>>  	size_t gstrings_size;
>>> +	netdev_features_t net_hw_features;
>>> +	netdev_features_t net_features;
>>
>>    Do we really need both of these here? 
> 
> R-Car has only Rx Checksum on E-Mac, where as Geth supports Rx Check Sum on E-Mac or Rx/Tx CheckSum on TOE.
> So there is a hw difference. Please let me know what is the best way to handle this?

   I meant that we could go with only one field of the net_features... Alternatively, we could use our own
feature bits...

>> It seems like the 'feartures'
>> mirrors the enabled features?
> 
> Can you please explain this little bit?

   Looks like I was wrong. :-)

[...]

> Regards,
> Biju

[...]

MBR, Sergei