netdev - Re: [PATCH] net: sky2: allow mac to come from dt

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Date:	Wed, 5 Mar 2014 07:38:22 -0800
From:	Tim Harvey <tharvey@...eworks.com>
To:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Cc:	Stephen Hemminger <stephen@...workplumber.org>,
	netdev <netdev@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH] net: sky2: allow mac to come from dt

On Wed, Mar 5, 2014 at 6:15 AM, Sergei Shtylyov
<sergei.shtylyov@...entembedded.com> wrote:
> Hello.

Hi Sergei,

>
>
> On 05-03-2014 10:22, Tim Harvey wrote:
>
>> The driver reads the mac address from the device registers which would
>> need to have been programmed by the bootloader.  This patch adds
>> the ability to pull the mac from devicetree via the pci device dt node.
>
>
>    I highly doubt that "[local-]mac-address" prop would be added to
> (autodiscovered) PCI device node.

I wouldn't have done this if I didn't need it ;)

The u-boot bootloader will do this for boards supporting devicetree.
Specifically, it will take the ethaddr/eth<n<addr/etc env vars and
apply a local-mac-address property to the devicetree using ethernet<n>
devicetree aliases.  This is to support MAC addresses coming from
EEPROM, eFUSE, etc.  The key here is that it doesn't need to know
where in the tree the eth devices are because it makes use of the
aliases node.

This of course requires that you do have an ethernet<n> alias to your
PCI based network device in your dt which I agree may seem strange for
an auto-probed bus, but in the case of a bootloader without PCI
support and/or sky2 support this seems the proper way to get the MAC
address from the bootloader to the driver.

>
> [...]
>
>> @@ -4805,8 +4808,27 @@ static struct net_device *sky2_init_netdev(struct
>> sky2_hw *hw, unsigned port,
>>
>>         dev->features |= dev->hw_features;
>>
>> +       /* try to get mac address in the following order:
>> +        * 1) from device tree data
>> +        * 2) from internal registers set by bootloader
>> +        */
>> +       iap = NULL;
>> +       if (IS_ENABLED(CONFIG_OF)) {
>> +               struct device_node *np = hw->pdev->dev.of_node;
>> +               if (np)
>> +                       iap = (unsigned char *) of_get_mac_address(np);
>> +       }
>> +
>> +       /* 2) mac registers set by bootloader
>> +        */
>> +       if (!iap || !is_valid_ether_addr(iap)) {
>> +               memcpy_fromio(&tmpaddr, hw->regs + B2_MAC_1 + port * 8,
>> +                       ETH_ALEN);
>
>
>    This line should start right under & on the previous line.

agreed - not sure why checkpatch.pl didn't catch that

>
>
>> +               iap = &tmpaddr[0];

agreed - I will change this as its more readable

>
>
>    Why not just 'tmpaddr'?
>
>> +       }
>> +
>
>
> WBR, Sergei
>

Thanks for the review!

Tim
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