net: mvneta: read MAC address from hardware when available

This patch improves the logic used by the mvneta driver to find a MAC
address for a particular interface. Until now, it was only looking at
the Device Tree, and if no address was found, was falling back to
generating a random MAC address.

This patch adds the intermediate solution of reading the MAC address
from the hardware registers, in case it has been set by the
bootloader. So the order is now:

 1) MAC address from the Device Tree
 2) MAC address from the hardware registers
 3) Random MAC address

This requires moving the MAC address initialization a little bit later
in the ->probe() code, because it now requires the hardware registers
to be remapped.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 drivers/net/ethernet/marvell/mvneta.c | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

Hello.

On 06/03/2013 08:41 PM, Thomas Petazzoni wrote:

> This patch improves the logic used by the mvneta driver to find a MAC
> address for a particular interface. Until now, it was only looking at
> the Device Tree, and if no address was found, was falling back to
> generating a random MAC address.
>
> This patch adds the intermediate solution of reading the MAC address
> from the hardware registers, in case it has been set by the
> bootloader. So the order is now:
>
>   1) MAC address from the Device Tree
>   2) MAC address from the hardware registers
>   3) Random MAC address
>
> This requires moving the MAC address initialization a little bit later
> in the ->probe() code, because it now requires the hardware registers
> to be remapped.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
>   drivers/net/ethernet/marvell/mvneta.c | 35 +++++++++++++++++++++++++++--------
>   1 file changed, 27 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index c966785..8c05cc5 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -2251,6 +2251,20 @@ static int mvneta_change_mtu(struct net_device *dev, int mtu)
>   	return 0;
>   }
>   
> +/* Get mac address */
> +static void mvneta_get_mac_addr(struct mvneta_port *pp, unsigned char *addr)
> +{
> +	u32 mac_addr_l, mac_addr_h;

    Empty line wouldn't hurt here, after declaration.

> +	mac_addr_l = mvreg_read(pp, MVNETA_MAC_ADDR_LOW);
> +	mac_addr_h = mvreg_read(pp, MVNETA_MAC_ADDR_HIGH);
> +	addr[0] = (mac_addr_h >> 24) & 0xFF;
> +	addr[1] = (mac_addr_h >> 16) & 0xFF;
> +	addr[2] = (mac_addr_h >> 8) & 0xFF;
> +	addr[3] = mac_addr_h & 0xFF;
> +	addr[4] = (mac_addr_l >> 8) & 0xFF;
> +	addr[5] = mac_addr_l & 0xFF;
> +}
> +
>   /* Handle setting mac address */
>   static int mvneta_set_mac_addr(struct net_device *dev, void *addr)
>   {
>   
[...]
> @@ -2740,6 +2748,17 @@ static int mvneta_probe(struct platform_device *pdev)
>   
>   	clk_prepare_enable(pp->clk);
>   
> +	dt_mac_addr = of_get_mac_address(dn);
> +	if (dt_mac_addr && is_valid_ether_addr(dt_mac_addr))
> +		memcpy(dev->dev_addr, dt_mac_addr, ETH_ALEN);
> +	else {
> +		mvneta_get_mac_addr(pp, hw_mac_addr);
> +		if (is_valid_ether_addr(hw_mac_addr))
> +			memcpy(dev->dev_addr, hw_mac_addr, ETH_ALEN);
> +		else
> +			eth_hw_addr_random(dev);
> +	}

    {} should be on both arms of the *if* statement.

WBR, Sergei

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On Mon, 2013-06-03 at 18:41 +0200, Thomas Petazzoni wrote:
> This patch improves the logic used by the mvneta driver to find a MAC
> address for a particular interface. Until now, it was only looking at
> the Device Tree, and if no address was found, was falling back to
> generating a random MAC address.
[]
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
[]
> @@ -2740,6 +2748,17 @@ static int mvneta_probe(struct platform_device *pdev)
[]
> +	dt_mac_addr = of_get_mac_address(dn);
> +	if (dt_mac_addr && is_valid_ether_addr(dt_mac_addr))
> +		memcpy(dev->dev_addr, dt_mac_addr, ETH_ALEN);
> +	else {
> +		mvneta_get_mac_addr(pp, hw_mac_addr);
> +		if (is_valid_ether_addr(hw_mac_addr))
> +			memcpy(dev->dev_addr, hw_mac_addr, ETH_ALEN);
> +		else
> +			eth_hw_addr_random(dev);
> +	}

maybe there could be a dmesg line like:

	const char *mac_from;
[...]
		mac_from = "device tree"
	else
[...]
			mac_from = "hardware"
		else
			mac_from = "random"
[...]
	netdev_info(dev, "Using %s mac address %pM\n",
		    mac_from, dev->dev_addr);


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