Subject: Re: [patch 1/1] phy/marvell: fix 88e1121 support

From: Cyril Chemparathy <[email-masked]>
Date: Mon, 18 Oct 2010 18:02:36 -0400

Hi,

On 10/18/2010 05:44 PM, Arnaud Patard wrote:
> Commit c477d0447db08068a497e7beb892b2b2a7bff64b added support for RGMII
> rx/tx delays except that it ends up clearing rx/tx delays bit for modes
> differents that RGMII*ID. Due to this, ethernet is not working anymore
> on my guruplug server +. This patch is fixing that.
> 
> Signed-off-by: Arnaud Patard <[email-masked]>
> Index: linux-2.6/drivers/net/phy/marvell.c
> ===================================================================
> --- linux-2.6.orig/drivers/net/phy/marvell.c	2010-10-18 22:46:09.000000000 +0200
> +++ linux-2.6/drivers/net/phy/marvell.c	2010-10-18 23:19:14.000000000 +0200
> @@ -199,13 +199,13 @@
>  	mscr = phy_read(phydev, MII_88E1121_PHY_MSCR_REG) &
>  		MII_88E1121_PHY_MSCR_DELAY_MASK;
>  
> -	if (phydev->interface == PHY_INTERFACE_MODE_RGMII_ID)
> -		mscr |= (MII_88E1121_PHY_MSCR_RX_DELAY |
> -			 MII_88E1121_PHY_MSCR_TX_DELAY);
> -	else if (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID)
> +	if (phydev->interface == PHY_INTERFACE_MODE_RGMII_RXID)
>  		mscr |= MII_88E1121_PHY_MSCR_RX_DELAY;
>  	else if (phydev->interface == PHY_INTERFACE_MODE_RGMII_TXID)
>  		mscr |= MII_88E1121_PHY_MSCR_TX_DELAY;
> +	else
> +		mscr |= (MII_88E1121_PHY_MSCR_RX_DELAY |
> +			 MII_88E1121_PHY_MSCR_TX_DELAY);
>  
>  	err = phy_write(phydev, MII_88E1121_PHY_MSCR_REG, mscr);
>  	if (err < 0)

This doesn't look right.  This change makes it impossible to configure
the phy without interface delays, i.e., PHY_INTERFACE_MODE_RGMII ends up
behaving the same as PHY_INTERFACE_MODE_RGMII_ID.

I think the correct fix would be to modify guruplug's interface mode to
PHY_INTERFACE_MODE_RGMII_ID if both TX and RX side delays are desired.

Regards
Cyril.