Subject: Re: [PATCH v3 net-next 5/6] net: ethernet: ti: am65-cpsw: retain PORT_VLAN_REG after suspend/resume

From: Maciej Fijalkowski <[email-masked]>
Date: Fri, 25 Nov 2022 14:21:17 +0100

On Wed, Nov 23, 2022 at 02:48:34PM +0200, Roger Quadros wrote:
> During suspend resume the context of PORT_VLAN_REG is lost so
> save it during suspend and restore it during resume for
> host port and slave ports.
> 
> Signed-off-by: Roger Quadros <[email-masked]>
> Signed-off-by: David S. Miller <[email-masked]>
> ---
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 7 +++++++
>  drivers/net/ethernet/ti/am65-cpsw-nuss.h | 4 ++++
>  2 files changed, 11 insertions(+)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index 0b59088e3728..f5357afde527 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -2875,7 +2875,9 @@ static int am65_cpsw_nuss_suspend(struct device *dev)
>  	struct am65_cpsw_port *port;
>  	struct net_device *ndev;
>  	int i, ret;
> +	struct am65_cpsw_host *host_p = am65_common_get_host(common);

Nit: I see that retrieving host pointer depends on getting the common
pointer first from dev_get_drvdata(dev) so pure RCT is not possible to
maintain here but nonetheless I would move this line just below the common
pointer:

	struct am65_cpsw_common *common = dev_get_drvdata(dev);
	struct am65_cpsw_host *host = am65_common_get_host(common);
	struct am65_cpsw_port *port;
	struct net_device *ndev;
	int i, ret;

Also I think plain 'host' for variable name is just fine, no need for _p
suffix to indicate it is a pointer. in that case you should go with
common_p etc.

>  
> +	host_p->vid_context = readl(host_p->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
>  	for (i = 0; i < common->port_num; i++) {
>  		port = &common->ports[i];
>  		ndev = port->ndev;
> @@ -2883,6 +2885,7 @@ static int am65_cpsw_nuss_suspend(struct device *dev)
>  		if (!ndev)
>  			continue;
>  
> +		port->vid_context = readl(port->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
>  		netif_device_detach(ndev);
>  		if (netif_running(ndev)) {
>  			rtnl_lock();
> @@ -2909,6 +2912,7 @@ static int am65_cpsw_nuss_resume(struct device *dev)
>  	struct am65_cpsw_port *port;
>  	struct net_device *ndev;
>  	int i, ret;
> +	struct am65_cpsw_host *host_p = am65_common_get_host(common);
>  
>  	ret = am65_cpsw_nuss_init_tx_chns(common);
>  	if (ret)
> @@ -2941,8 +2945,11 @@ static int am65_cpsw_nuss_resume(struct device *dev)
>  		}
>  
>  		netif_device_attach(ndev);
> +		writel(port->vid_context, port->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
>  	}
>  
> +	writel(host_p->vid_context, host_p->port_base + AM65_CPSW_PORT_VLAN_REG_OFFSET);
> +
>  	return 0;
>  }
>  #endif /* CONFIG_PM_SLEEP */
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.h b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
> index 2c9850fdfcb6..e95cc37a7286 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.h
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
> @@ -55,12 +55,16 @@ struct am65_cpsw_port {
>  	bool				rx_ts_enabled;
>  	struct am65_cpsw_qos		qos;
>  	struct devlink_port		devlink_port;
> +	/* Only for suspend resume context */
> +	u32				vid_context;
>  };
>  
>  struct am65_cpsw_host {
>  	struct am65_cpsw_common		*common;
>  	void __iomem			*port_base;
>  	void __iomem			*stat_base;
> +	/* Only for suspend resume context */
> +	u32				vid_context;
>  };
>  
>  struct am65_cpsw_tx_chn {
> -- 
> 2.17.1
>