[PATCH] net: bcmgenet: Don't set ID_MODE_DIS when not using RGMII

[Florian Fainelli]

On 2/20/20 8:36 AM, Nicolas Saenz Julienne wrote:
> As per Linux's driver, ID_MODE_DIS is only set when the PHY interface is
> RGMII. Don't enable it for the rest of setups.
> 
> This has been seen to misconfigure RPi4's PHY when booting Linux.
> 
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne at suse.de>

Does the failure look like the following: you have a driver for the
Broadcom PHY used on the Pi4 in u-boot, and the phy_dev->interface value
is being used to configure the Ethernet PHY chip in a certain way.

Later when you boot Linux, you do not have CONFIG_BROADCOM_PHY enabled
so the Generic PHY driver gets used instead, and there is a disagreement
between the AMAC and PHY as to whom should be adding the delays?

At any rate:

Reviewed-by: Florian Fainelli <f.fainelli at gmail.com>

> ---
>  drivers/net/bcmgenet.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/bcmgenet.c b/drivers/net/bcmgenet.c
> index 8f4848aec6..e971b556ac 100644
> --- a/drivers/net/bcmgenet.c
> +++ b/drivers/net/bcmgenet.c
> @@ -448,7 +448,10 @@ static int bcmgenet_adjust_link(struct bcmgenet_eth_priv *priv)
>  	}
>  
>  	clrsetbits_32(priv->mac_reg + EXT_RGMII_OOB_CTRL, OOB_DISABLE,
> -			RGMII_LINK | RGMII_MODE_EN | ID_MODE_DIS);
> +			RGMII_LINK | RGMII_MODE_EN);
> +
> +	if (phy_dev->interface == PHY_INTERFACE_MODE_RGMII)
> +		setbits_32(priv->mac_reg + EXT_RGMII_OOB_CTRL, ID_MODE_DIS);
>  
>  	writel(speed << CMD_SPEED_SHIFT, (priv->mac_reg + UMAC_CMD));
>  
> 


-- 
Florian