linux-kernel - Re: [PATCH net-next v3 2/2] net: dsa: mt7530: simplify core operations

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Date: Tue, 23 Apr 2024 10:40:47 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Arınç ÜNAL <arinc.unal@...nc9.com>, Daniel
 Golle <daniel@...rotopia.org>, DENG Qingfang <dqfext@...il.com>, Sean Wang
 <sean.wang@...iatek.com>, Andrew Lunn <andrew@...n.ch>, Florian Fainelli
 <f.fainelli@...il.com>, Vladimir Oltean <olteanv@...il.com>, "David S.
 Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub
 Kicinski <kuba@...nel.org>, Matthias Brugger <matthias.bgg@...il.com>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Cc: Bartel Eerdekens <bartel.eerdekens@...stell8.be>,
 mithat.guner@...ont.com,  erkin.bozoglu@...ont.com, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org,  linux-arm-kernel@...ts.infradead.org,
 linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH net-next v3 2/2] net: dsa: mt7530: simplify core
 operations

On Thu, 2024-04-18 at 08:35 +0300, Arınç ÜNAL wrote:
> The core_rmw() function calls core_read_mmd_indirect() to read the
> requested register, and then calls core_write_mmd_indirect() to write the
> requested value to the register. Because Clause 22 is used to access Clause
> 45 registers, some operations on core_write_mmd_indirect() are
> unnecessarily run. Get rid of core_read_mmd_indirect() and
> core_write_mmd_indirect(), and run only the necessary operations on
> core_write() and core_rmw().
> 
> Reviewed-by: Daniel Golle <daniel@...rotopia.org>
> Tested-by: Daniel Golle <daniel@...rotopia.org>
> Signed-off-by: Arınç ÜNAL <arinc.unal@...nc9.com>
> ---
>  drivers/net/dsa/mt7530.c | 108 +++++++++++++++++++----------------------------
>  1 file changed, 43 insertions(+), 65 deletions(-)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 64b1f6320b9a..e0cb194019f8 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -74,116 +74,94 @@ static const struct mt7530_mib_desc mt7530_mib[] = {
>  	MIB_DESC(1, 0xb8, "RxArlDrop"),
>  };
>  
> -/* Since phy_device has not yet been created and
> - * phy_{read,write}_mmd_indirect is not available, we provide our own
> - * core_{read,write}_mmd_indirect with core_{clear,write,set} wrappers
> - * to complete this function.
> - */
> -static int
> -core_read_mmd_indirect(struct mt7530_priv *priv, int prtad, int devad)
> +static void
> +mt7530_mutex_lock(struct mt7530_priv *priv)
> +{
> +	if (priv->bus)
> +		mutex_lock_nested(&priv->bus->mdio_lock, MDIO_MUTEX_NESTED);
> +}
> +
> +static void
> +mt7530_mutex_unlock(struct mt7530_priv *priv)
> +{
> +	if (priv->bus)
> +		mutex_unlock(&priv->bus->mdio_lock);
> +}
> +
> +static void
> +core_write(struct mt7530_priv *priv, u32 reg, u32 val)
>  {
>  	struct mii_bus *bus = priv->bus;
> -	int value, ret;
> +	int ret;
> +
> +	mt7530_mutex_lock(priv);
>  
>  	/* Write the desired MMD Devad */
>  	ret = bus->write(bus, MT753X_CTRL_PHY_ADDR(priv->mdiodev->addr),
> -			 MII_MMD_CTRL, devad);
> +			 MII_MMD_CTRL, MDIO_MMD_VEND2);
>  	if (ret < 0)
>  		goto err;
>  
>  	/* Write the desired MMD register address */
>  	ret = bus->write(bus, MT753X_CTRL_PHY_ADDR(priv->mdiodev->addr),
> -			 MII_MMD_DATA, prtad);
> +			 MII_MMD_DATA, reg);
>  	if (ret < 0)
>  		goto err;
>  
>  	/* Select the Function : DATA with no post increment */
>  	ret = bus->write(bus, MT753X_CTRL_PHY_ADDR(priv->mdiodev->addr),
> -			 MII_MMD_CTRL, devad | MII_MMD_CTRL_NOINCR);
> +			 MII_MMD_CTRL, MDIO_MMD_VEND2 | MII_MMD_CTRL_NOINCR);
>  	if (ret < 0)
>  		goto err;

What about a possible follow-up, moving the above writes in a separate
helper (say, 'core_select_register' or the like) and reusing it here
and in core_rmw() ?

Not blocking this series, I'm applying it.

Thanks,

Paolo