netdev - RE: [PATCH v2] fsl/fman: Use random MAC address when none is given

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Message-ID: <DB8PR04MB6985F8A2EB05F426F2CF8C0AECE20@DB8PR04MB6985.eurprd04.prod.outlook.com>
Date:   Thu, 5 Mar 2020 13:38:01 +0000
From:   Madalin Bucur <madalin.bucur@....com>
To:     Sascha Hauer <s.hauer@...gutronix.de>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH v2] fsl/fman: Use random MAC address when none is given

> -----Original Message-----
> From: Sascha Hauer <s.hauer@...gutronix.de>
> Sent: Thursday, March 5, 2020 2:34 PM
> To: netdev@...r.kernel.org
> Cc: Madalin Bucur <madalin.bucur@....com>; Sascha Hauer
> <s.hauer@...gutronix.de>
> Subject: [PATCH v2] fsl/fman: Use random MAC address when none is given
> 
> There's no need to fail probing when no MAC address is given in the
> device tree, just use a random MAC address.
> 
> Signed-off-by: Sascha Hauer <s.hauer@...gutronix.de>
> ---
> 
> Changes since v1:
> - Remove printing of permanent MAC address
> 
>  drivers/net/ethernet/freescale/dpaa/dpaa_eth.c   | 11 +++++++++--
>  drivers/net/ethernet/freescale/fman/fman_memac.c |  4 ----
>  drivers/net/ethernet/freescale/fman/mac.c        | 10 ++--------
>  3 files changed, 11 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> index fd93d542f497..fc117eab788d 100644
> --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> @@ -233,8 +233,15 @@ static int dpaa_netdev_init(struct net_device
> *net_dev,
>  	net_dev->features |= net_dev->hw_features;
>  	net_dev->vlan_features = net_dev->features;
> 
> -	memcpy(net_dev->perm_addr, mac_addr, net_dev->addr_len);
> -	memcpy(net_dev->dev_addr, mac_addr, net_dev->addr_len);
> +	if (is_valid_ether_addr(mac_addr)) {
> +		dev_info(dev, "FMan MAC address: %pM\n", mac_addr);
> +		memcpy(net_dev->perm_addr, mac_addr, net_dev->addr_len);
> +		memcpy(net_dev->dev_addr, mac_addr, net_dev->addr_len);
> +	} else {
> +		eth_hw_addr_random(net_dev);
> +		dev_info(dev, "Using random MAC address: %pM\n",
> +			 net_dev->dev_addr);
> +	}

To make the HW MAC aware of the new random address you set in the dpaa_eth,
you also need to call mac_dev->change_addr() after eth_hw_addr_random(), like
it's done in dpaa_set_mac_address():

        err = mac_dev->change_addr(mac_dev->fman_mac,
                                   (enet_addr_t *)net_dev->dev_addr);

This will write the new MAC address in the MAC HW registers.

> 
>  	net_dev->ethtool_ops = &dpaa_ethtool_ops;
> 
> diff --git a/drivers/net/ethernet/freescale/fman/fman_memac.c
> b/drivers/net/ethernet/freescale/fman/fman_memac.c
> index e1901874c19f..9e2372688405 100644
> --- a/drivers/net/ethernet/freescale/fman/fman_memac.c
> +++ b/drivers/net/ethernet/freescale/fman/fman_memac.c
> @@ -596,10 +596,6 @@ static void setup_sgmii_internal_phy_base_x(struct
> fman_mac *memac)
> 
>  static int check_init_parameters(struct fman_mac *memac)
>  {
> -	if (memac->addr == 0) {
> -		pr_err("Ethernet MAC must have a valid MAC address\n");
> -		return -EINVAL;
> -	}
>  	if (!memac->exception_cb) {
>  		pr_err("Uninitialized exception handler\n");
>  		return -EINVAL;
> diff --git a/drivers/net/ethernet/freescale/fman/mac.c
> b/drivers/net/ethernet/freescale/fman/mac.c
> index 55f2122c3217..9de76bc4ebde 100644
> --- a/drivers/net/ethernet/freescale/fman/mac.c
> +++ b/drivers/net/ethernet/freescale/fman/mac.c
> @@ -724,12 +724,8 @@ static int mac_probe(struct platform_device
> *_of_dev)
> 
>  	/* Get the MAC address */
>  	mac_addr = of_get_mac_address(mac_node);
> -	if (IS_ERR(mac_addr)) {
> -		dev_err(dev, "of_get_mac_address(%pOF) failed\n", mac_node);
> -		err = -EINVAL;
> -		goto _return_of_get_parent;
> -	}
> -	ether_addr_copy(mac_dev->addr, mac_addr);
> +	if (!IS_ERR(mac_addr))
> +		ether_addr_copy(mac_dev->addr, mac_addr);
> 
>  	/* Get the port handles */
>  	nph = of_count_phandle_with_args(mac_node, "fsl,fman-ports", NULL);
> @@ -855,8 +851,6 @@ static int mac_probe(struct platform_device *_of_dev)
>  	if (err < 0)
>  		dev_err(dev, "fman_set_mac_active_pause() = %d\n", err);
> 
> -	dev_info(dev, "FMan MAC address: %pM\n", mac_dev->addr);
> -
>  	priv->eth_dev = dpaa_eth_add_device(fman_id, mac_dev);
>  	if (IS_ERR(priv->eth_dev)) {
>  		dev_err(dev, "failed to add Ethernet platform device for MAC
> %d\n",
> --
> 2.25.1