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Subject: Re: [PATCH net-next v2 11/21] net: ravb: Move DBAT configuration to
 the driver's ndo_open API
To: claudiu beznea <claudiu.beznea@tuxon.dev>, <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>
 <b17c6124-0b84-40b2-a254-cce617f73cf2@tuxon.dev>
From: Sergey Shtylyov <s.shtylyov@omp.ru>
Organization: Open Mobile Platform
Message-ID: <59ba595a-ab79-cc5d-feff-dad60e80c44f@omp.ru>
Date: Tue, 19 Dec 2023 21:54:49 +0300
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On 12/17/23 3:54 PM, claudiu beznea 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.,

   It's purpose is to configure AVB-DMAC and DBAT is the AVB-DMAC register,
right?

> ravb_set_ringparam(), ravb_tx_timeout_work().

   I know. Its value is only calculated once, in ravb_probe(), right?

> I'm afraid we may broke the behavior of these if DBAT setup is moved

   Do not be afraid! :-)

> in ravb_dmac_init(). This is also
> valid for setting delay (see patch 10/12).

   I don't think there will be a problem either... but maybe we
should call it in ravb_emac_init() indeed.

[...]

MBR, Sergey