Re: [PATCH net-next v2 13/21] net: ravb: Set config mode in ndo_open and reset mode in ndo_close

[Sergey Shtylyov]

On 12/14/23 2:45 PM, Claudiu wrote:

> From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
> 
> As some IP variants switch to reset mode (and thus registers' content is

   Register.

> lost) when setting clocks (due to module standby functionality) to be able
> to implement runtime PM and save more power, set the IP's operation mode to

   Operating.

> reset at the end of the probe. Along with it, in the ndo_open API the IP
> will be switched to configuration, then operational 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@xxxxxxxxxxxxxx>
[..]

> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index db9222fc57c2..31a1f8a83652 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
[...]
> @@ -1821,13 +1845,19 @@ static int ravb_open(struct net_device *ndev)
>  	if (info->nc_queues)
>  		napi_enable(&priv->napi[RAVB_NC]);
>  
> +	/* Set AVB config mode */
> +	error = ravb_set_config_mode(ndev);
> +	if (error)
> +		goto out_napi_off;
> +

   I suspect this too belongs in ravb_dmac_init() now...

[...]
> @@ -2875,19 +2886,30 @@ static int ravb_probe(struct platform_device *pdev)
>  
>  	device_set_wakeup_capable(&pdev->dev, 1);
>  
> +	/* Reset MAC as the module will be runtime disabled at this moment.
> +	 * This saves power. MAC will be switched back to configuration mode
> +	 * in ravb_open().
> +	 */
> +	error = ravb_set_reset_mode(ndev);
> +	if (error)
> +		goto out_netdev_unregister;
> +

   I think this now races with the register_netdev() call above (the device
can be opened before it returns)! Should be called before register_netdev()...

[...]

MBR, Sergey