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Message-ID: <5b6eaff5-5358-46ff-8072-8a70af1e5d5f@tuxon.dev>
Date: Wed, 20 Dec 2023 14:02:57 +0200
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Subject: Re: [PATCH net-next v2 10/21] net: ravb: Move delay mode set in the
 driver's ndo_open API
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To: Sergey Shtylyov <s.shtylyov@omp.ru>, davem@davemloft.net,
 edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
 richardcochran@gmail.com, p.zabel@pengutronix.de,
 yoshihiro.shimoda.uh@renesas.com, wsa+renesas@sang-engineering.com,
 geert+renesas@glider.be
Cc: netdev@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
 linux-kernel@vger.kernel.org,
 Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
References: <20231214114600.2451162-1-claudiu.beznea.uj@bp.renesas.com>
 <20231214114600.2451162-11-claudiu.beznea.uj@bp.renesas.com>
 <421c684d-7092-d7a8-e00a-6abe40c557c5@omp.ru>
 <58b11076-3e8e-42a0-864f-7ad16abaccd6@tuxon.dev>
 <c00db758-54ca-80a9-7ba3-9a6ce61f9224@omp.ru>
From: claudiu beznea <claudiu.beznea@tuxon.dev>
In-Reply-To: <c00db758-54ca-80a9-7ba3-9a6ce61f9224@omp.ru>
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On 19.12.2023 20:40, Sergey Shtylyov wrote:
> On 12/17/23 3:49 PM, claudiu beznea wrote:
> 
> [...]
>>>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>>>
>>>> Delay parse and set were done in the driver's probe API. As some IP
>>>
>>>    Parsing and setting?
>>>
>>>> variants switch to reset mode (and thus registers' content is lost) when
>>>
>>>    Register.
>>>
>>>> setting clocks (due to module standby functionality) to be able to
>>>> implement runtime PM keep the delay parsing in the driver's probe function
>>>> and move the delay apply function to the driver's ndo_open API.
>>>
>>>    Applying?
>>>
>>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>> [...]
>>>
>>>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>>>> index 5e01e03e1b43..04eaa1967651 100644
>>>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>>>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>>> [...]
>>>> @@ -1806,6 +1821,8 @@ static int ravb_open(struct net_device *ndev)
>>>>  	if (info->nc_queues)
>>>>  		napi_enable(&priv->napi[RAVB_NC]);
>>>>  
>>>> +	ravb_set_delay_mode(ndev);
>>>> +
>>>
>>>    I suspect this belongs in ravb_dmac_init() now...
>>
>> I'm confused... Why? To me this seems more like MAC-PHY interface related.
> 
>    APSR's full name is AVB-DMAC product specific register. :-)

As ravb_dmac_init() is called in multiple places I don't think it worth
configuring delays more than once in ravb_open().

Moreover TX/RX delay is something specific to the MAC-PHY interface (and
could be influenced also by the wiring length b/w MAC and PHY).

Just because it is in the DMAC address space I don't think it worth having
it in ravb_dmac_init() (for the above mentioned reasons).

> 
>> Though I'm not sure what ravb_dmac_init() purpose is.
> 
>    To configure and start the AVB-DMAC, apparently. :-)
> 
> [...]
> 
> MRB, Sergey