linux-kernel - Re: [PATCH net-next v3 13/19] net: ravb: Set config mode in ndo_open and reset mode in ndo

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Date: Tue, 9 Jan 2024 07:42:52 +0200
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Sergey Shtylyov <s.shtylyov@....ru>, davem@...emloft.net,
 edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
 richardcochran@...il.com, p.zabel@...gutronix.de,
 yoshihiro.shimoda.uh@...esas.com, wsa+renesas@...g-engineering.com
Cc: netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
 linux-kernel@...r.kernel.org, geert+renesas@...der.be,
 Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH net-next v3 13/19] net: ravb: Set config mode in ndo_open
 and reset mode in ndo_close



On 08.01.2024 21:28, Sergey Shtylyov wrote:
> On 1/5/24 11:23 AM, Claudiu wrote:
> 
>> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>>
>> 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 and save more power, set the IP's operating mode to
>> reset at the end of the probe. Along with it, in the ndo_open API the IP
>> will be switched to configuration, then operation mode. In the ndo_close
>> API, the IP will be switched back to reset mode. This allows implementing
>> runtime PM and, along with it, save more power when the IP is not used.
>>
>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>> ---
>>
>> Changes in v3:
>> - fixed typos in patch description
>> - in ravb_probe() switch the hardware to reset mode just after phy
>>   initialization
>>
>> Changes in v2:
>> - none; this patch is new
>>
>>
>>  drivers/net/ethernet/renesas/ravb_main.c | 78 ++++++++++++++----------
>>  1 file changed, 46 insertions(+), 32 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
>> index 1cc1ecd8d6a8..434b4777de5e 100644
>> --- a/drivers/net/ethernet/renesas/ravb_main.c
>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> [...]
>> @@ -2746,11 +2755,6 @@ static int ravb_probe(struct platform_device *pdev)
>>  	ndev->netdev_ops = &ravb_netdev_ops;
>>  	ndev->ethtool_ops = &ravb_ethtool_ops;
>>  
>> -	/* Set AVB config mode */
>> -	error = ravb_set_config_mode(ndev);
>> -	if (error)
>> -		goto out_rpm_put;
>> -
>>  	error = ravb_compute_gti(ndev);
>>  	if (error)
>>  		goto out_rpm_put;
>> @@ -2785,13 +2789,23 @@ static int ravb_probe(struct platform_device *pdev)
>>  		eth_hw_addr_random(ndev);
>>  	}
>>  
>> +	/* Set config mode as this is needed for PHY initialization. */
>> +	error = ravb_set_opmode(ndev, CCC_OPC_CONFIG);
> 
>    Hm... don't you need this at laest before calling ravb_read_mac_address()
> just above?

I asked myself this, haven't experienced issues w/ it while working on this
patch thus I kept it as is. In theory, yes, it should be above that call.
I'll move it there.

Thank you,
Claudiu Beznea

> 
>> +	if (error)
>> +		goto out_rpm_put;
>> +
>>  	/* MDIO bus init */
>>  	error = ravb_mdio_init(priv);
>>  	if (error) {
>>  		dev_err(&pdev->dev, "failed to initialize MDIO\n");
>> -		goto out_dma_free;
>> +		goto out_reset_mode;
>>  	}
>>  
>> +	/* Undo previous switch to config opmode. */
>> +	error = ravb_set_opmode(ndev, CCC_OPC_RESET);
>> +	if (error)
>> +		goto out_mdio_release;
>> +
>>  	netif_napi_add(ndev, &priv->napi[RAVB_BE], ravb_poll);
>>  	if (info->nc_queues)
>>  		netif_napi_add(ndev, &priv->napi[RAVB_NC], ravb_poll);
> [...]
> 
> MBR, Sergey