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: Mon, 28 Nov 2022 11:11:30 +0100

On Mon, Nov 28, 2022 at 11:21:40AM +0200, Roger Quadros wrote:
> On 25/11/2022 15:21, Maciej Fijalkowski wrote:
> > 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;
> 
> OK.
> 
> > 
> > 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 is the naming convention used throughout the driver.
> Do think it is a good idea to change it at this one place?

No, maybe think of a refactor throughout whole codebase, changing it in a
single place would be odd.

> 
> > 
> >>  
> >> +	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
> >>
> 
> --
> cheers,
> -roger