Re: [PATCH net-next v4 2/5] net: stmmac: introduce pcs_init/pcs_exit stmmac operations

[Serge Semin]

Hi Romain

On Wed, Apr 24, 2024 at 11:06:20AM +0200, Romain Gantois wrote:
> From: "Russell King (Oracle)" <rmk+kernel@xxxxxxxxxxxxxxx>
> 
> Introduce a mechanism whereby platforms can create their PCS instances
> prior to the network device being published to userspace, but after
> some of the core stmmac initialisation has been completed. This means
> that the data structures that platforms need will be available.
> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
> Reviewed-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
> [rgantois: removed second parameters of new callbacks]
> Signed-off-by: Romain Gantois <romain.gantois@xxxxxxxxxxx>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 14 ++++++++++++++
>  include/linux/stmmac.h                            |  2 ++
>  2 files changed, 16 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 59bf83904b62d..bee9c9ab31a88 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -7200,6 +7200,12 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
>  	if (ret)
>  		return ret;
>  
> +	if (priv->plat->pcs_init) {
> +		ret = priv->plat->pcs_init(priv);
> +		if (ret)
> +			return ret;
> +	}
> +

Once again. There is a ready-to-use stmmac_xpcs_setup() method. Which
is currently intended for the XPCS setups. Let's collect all the
PCS-related stuff in a single place there. That will make code cleaner
and easier to read. This was discussed on v3:

https://lore.kernel.org/netdev/42chuecdt7dpgm6fcrtt2crifvv5hflmtnmdrw5fvk3r7pwjgu@hlcv56dbeosf/

You agreed to do that, but just ignored in result. I'll repeat what I
said in v3:

On Tue, 16 Apr 2024 16:41:33 +0300, Serge Semin wrote:
> I am currently working on my Memory-mapped DW XPCS patchset cooking:
> https://lore.kernel.org/netdev/20231205103559.9605-1-fancer.lancer@xxxxxxxxx/
> The changes in this series seems to intersect to what is/will be
> introduced in my patchset. In particular as before I am going to
> use the "pcs-handle" property for getting the XPCS node. If so what
> about collecting PCS-related things in a single place. Like this:
>
> int stmmac_xpcs_setup(struct net_device *ndev)
> {
> 	...
> 
> 	if (priv->plat->pcs_init) {
> 		return priv->plat->pcs_init(priv); /* Romain' part */
> 	} else if (fwnode_property_present(priv->plat->port_node, "pcs-handle")) {
> 		/* My DW XPCS part */
> 	} else if (priv->plat->mdio_bus_data && priv->plat->mdio_bus_data->has_xpcs) {
> 		/* Currently implemented procedure */
> 	}
> 
> 	...
> }
>
> void stmmac_xpcs_clean(struct net_device *ndev)
> {
> 	...
> 
> 	if (priv->plat->pcs_exit) {
> 		priv->plat->pcs_exit(priv);
> 		return;
> 
> 	}
> 
> 	xpcs_destroy(priv->hw->xpcs);
> 	priv->hw->xpcs = NULL;
> }
> 
> Please see the last two patches in my series:
> https://lore.kernel.org/netdev/20231205103559.9605-16-fancer.lancer@xxxxxxxxx/
> https://lore.kernel.org/netdev/20231205103559.9605-17-fancer.lancer@xxxxxxxxx/
> as a reference of how the changes could be provided.

You replied it was a good idea, but the function names should be
renamed. That's not a problem. Just create a pre-requisite patch which
does that. So the patch in the subject could be replaced with four
subsequent patches:

1. Move the conditional XPCS-setup execution into the
stmmac_xpcs_setup() method. This change is partly implemented here
https://lore.kernel.org/netdev/20231205103559.9605-17-fancer.lancer@xxxxxxxxx/

2. Rename stmmac_xpcs_setup() method to just stmmac_pcs_setup() as a
preparation before adding the platform-specific PCS init()/exit()
callbacks.

3. Introduce the PCS-cleanup method. You can pick it up from here, but
use the stmmac_pcs_clean() name:
https://lore.kernel.org/netdev/20231205103559.9605-16-fancer.lancer@xxxxxxxxx/

4. Add pcc_init()/pcs_exit() callbacks as it's done in this patch but
call them in the stmmac_pcs_setup()/stmmac_pcs_clean() methods
instead of open-coding in the more generic
stmmac_hw_init()/stmmac_hw_exit() functions.

It doesn't look as that much hard thing to do, but will cause having a
better readable code by providing a single coherent function for all
PCS'es.

-Serge(y)

>  	/* Get the HW capability (new GMAC newer than 3.50a) */
>  	priv->hw_cap_support = stmmac_get_hw_features(priv);
>  	if (priv->hw_cap_support) {
> @@ -7282,6 +7288,12 @@ static int stmmac_hw_init(struct stmmac_priv *priv)
>  	return 0;
>  }
>  
> +static void stmmac_hw_exit(struct stmmac_priv *priv)
> +{
> +	if (priv->plat->pcs_exit)
> +		priv->plat->pcs_exit(priv);
> +}
> +
>
> [...]