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Message-ID: <b17c6124-0b84-40b2-a254-cce617f73cf2@tuxon.dev>
Date: Sun, 17 Dec 2023 14:54:18 +0200
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Subject: Re: [PATCH net-next v2 11/21] net: ravb: Move DBAT configuration to
 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>
 <20231214114600.2451162-12-claudiu.beznea.uj@bp.renesas.com>
 <a93c0673-2876-5bb2-29aa-0d0208b97b10@omp.ru>
 <4721c4e6-cc0f-48bd-8b14-4a8217ada1fd@omp.ru>
From: claudiu beznea <claudiu.beznea@tuxon.dev>
In-Reply-To: <4721c4e6-cc0f-48bd-8b14-4a8217ada1fd@omp.ru>
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On 15.12.2023 22:01, Sergey Shtylyov wrote:
> On 12/15/23 12:03 AM, Sergey Shtylyov wrote:
> [...]
> 
>>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>>
>>> DBAT setup was done in the driver's probe API. As some IP variants switch
>>> to reset mode (and thus registers' content is lost) when setting clocks
>>> (due to module standby functionality) to be able to implement runtime PM
>>> move the DBAT configuration in the driver's ndo_open API.
>>>
>>> This commit prepares the code for the addition of runtime PM.
>>>
>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>
>> Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
>>
>> [...]
>>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>>> index 04eaa1967651..6b8ca08be35e 100644
>>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
>>> @@ -1822,6 +1822,7 @@ static int ravb_open(struct net_device *ndev)
>>>  		napi_enable(&priv->napi[RAVB_NC]);
>>>  
>>>  	ravb_set_delay_mode(ndev);
>>> +	ravb_write(ndev, priv->desc_bat_dma, DBAT);
> 
>    Looking at it again, I suspect this belong in ravb_dmac_init()...

ravb_dmac_init() is called from multiple places in this driver, e.g.,
ravb_set_ringparam(), ravb_tx_timeout_work(). I'm afraid we may broke the
behavior of these if DBAT setup is moved in ravb_dmac_init(). This is also
valid for setting delay (see patch 10/12).

> 
>>>  
>>>  	/* Device init */
>>>  	error = ravb_dmac_init(ndev);
> [...]
> 
> MBR, Sergey