linux-kernel - Re: [PATCH net-next v5 2/7] net: stmmac: Add dedicated XPCS cleanup method

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Message-ID: <4wdcmcb2yxneynxtppestl6cp25z5xge3hfv7o47bxwpafn4cg@mtvc3ls2cxij>
Date: Fri, 3 May 2024 01:33:43 +0300
From: Serge Semin <fancer.lancer@...il.com>
To: Romain Gantois <romain.gantois@...tlin.com>
Cc: "David S. Miller" <davem@...emloft.net>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Geert Uytterhoeven <geert+renesas@...der.be>, Magnus Damm <magnus.damm@...il.com>, 
	Alexandre Torgue <alexandre.torgue@...s.st.com>, Jose Abreu <joabreu@...opsys.com>, 
	Maxime Coquelin <mcoquelin.stm32@...il.com>, Russell King <linux@...linux.org.uk>, 
	Clément Léger <clement.leger@...tlin.com>, Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
	netdev@...r.kernel.org, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-renesas-soc@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com, 
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH net-next v5 2/7] net: stmmac: Add dedicated XPCS cleanup
 method

Hi Romain

On Tue, Apr 30, 2024 at 09:29:42AM +0200, Romain Gantois wrote:
> From: Serge Semin <fancer.lancer@...il.com>
> 
> Currently the XPCS handler destruction is performed in the
> stmmac_mdio_unregister() method. It doesn't look good because the handler
> isn't originally created in the corresponding protagonist
> stmmac_mdio_unregister(), but in the stmmac_xpcs_setup() function. In
> order to have more coherent MDIO and XPCS setup/cleanup procedures,
> let's move the DW XPCS destruction to the dedicated stmmac_pcs_clean()
> method.
> 
> This method will also be used to cleanup PCS hardware using the
> pcs_exit() callback that will be introduced to stmmac in a subsequent
> patch.
> 
> Signed-off-by: Serge Semin <fancer.lancer@...il.com>
> Co-developed-by: Romain Gantois <romain.gantois@...tlin.com>
> Signed-off-by: Romain Gantois <romain.gantois@...tlin.com>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac.h      |  1 +
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |  6 +++++-
>  drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 12 +++++++++---
>  3 files changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> index dddcaa9220cc3..7e0d727ed795b 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
> @@ -361,6 +361,7 @@ int stmmac_mdio_unregister(struct net_device *ndev);
>  int stmmac_mdio_register(struct net_device *ndev);
>  int stmmac_mdio_reset(struct mii_bus *mii);
>  int stmmac_xpcs_setup(struct mii_bus *mii);
> +void stmmac_pcs_clean(struct stmmac_priv *priv);
>  void stmmac_set_ethtool_ops(struct net_device *netdev);
>  
>  int stmmac_init_tstamp_counter(struct stmmac_priv *priv, u32 systime_flags);
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 59bf83904b62d..2a55c5d07f6b8 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -7789,8 +7789,9 @@ int stmmac_dvr_probe(struct device *device,
>  
>  error_netdev_register:
>  	phylink_destroy(priv->phylink);
> -error_xpcs_setup:
>  error_phy_setup:
> +	stmmac_pcs_clean(priv);
> +error_xpcs_setup:
>  	if (priv->hw->pcs != STMMAC_PCS_TBI &&
>  	    priv->hw->pcs != STMMAC_PCS_RTBI)
>  		stmmac_mdio_unregister(ndev);
> @@ -7832,6 +7833,9 @@ void stmmac_dvr_remove(struct device *dev)
>  	if (priv->plat->stmmac_rst)
>  		reset_control_assert(priv->plat->stmmac_rst);
>  	reset_control_assert(priv->plat->stmmac_ahb_rst);
> +
> +	stmmac_pcs_clean(priv);
> +
>  	if (priv->hw->pcs != STMMAC_PCS_TBI &&
>  	    priv->hw->pcs != STMMAC_PCS_RTBI)
>  		stmmac_mdio_unregister(ndev);
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> index 0542cfd1817e6..508bd39cbe2b3 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> @@ -523,6 +523,15 @@ int stmmac_xpcs_setup(struct mii_bus *bus)
>  	return 0;
>  }
>  

> +void stmmac_pcs_clean(struct stmmac_priv *priv)

Ideally it would have been great to have the entire driver fixed to
accept the stmmac_priv pointer as the functions argument. But this
would be too tiresome. Anyway seeing the PCS-setup protagonist method
has the net_device pointer passed I would implement the same prototype
for the antagonist even though it would require an additional local
variable. That will make the MDIO and PCS local interface-functions
looking alike and as if unified. That is the reason of why I made
stmmac_xpcs_clean() accepting the net_device pointer. 

Alternatively both stmmac_pcs_setup() and stmmac_pcs_clean() could be
converted to just accepting a pointer to the stmmac_priv instance.

-Serge(y)

> +{
> +	if (!priv->hw->xpcs)
> +		return;
> +
> +	xpcs_destroy(priv->hw->xpcs);
> +	priv->hw->xpcs = NULL;
> +}
> +
>  /**
>   * stmmac_mdio_register
>   * @ndev: net device structure
> @@ -679,9 +688,6 @@ int stmmac_mdio_unregister(struct net_device *ndev)
>  	if (!priv->mii)
>  		return 0;
>  
> -	if (priv->hw->xpcs)
> -		xpcs_destroy(priv->hw->xpcs);
> -
>  	mdiobus_unregister(priv->mii);
>  	priv->mii->priv = NULL;
>  	mdiobus_free(priv->mii);
> 
> -- 
> 2.44.0
>