Subject: Re: [PATCH] stmmac: Add support for SIMATIC IOT2000 platform
To: Andy Shevchenko <andy.shevchenko@gmail.com>
References: <8c536123-6189-e0b6-1977-dc7a521718dd@siemens.com>
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Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        netdev <netdev@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Sascha Weisenberger <sascha.weisenberger@siemens.com>
From: Jan Kiszka <jan.kiszka@siemens.com>
Message-ID: <d7216317-e749-1347-972f-28dfe57038c0@siemens.com>
Date: Tue, 25 Apr 2017 11:00:47 +0200
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On 2017-04-25 09:30, Andy Shevchenko wrote:
> On Tue, Apr 25, 2017 at 8:44 AM, Jan Kiszka <jan.kiszka@siemens.com> wrote:
>> On 2017-04-24 23:27, Andy Shevchenko wrote:
>>> On Mon, Apr 24, 2017 at 10:27 PM, Jan Kiszka <jan.kiszka@siemens.com> wrote:
>>>> The IOT2000 is industrial controller platform, derived from the Intel
>>>> Galileo Gen2 board. The variant IOT2020 comes with one LAN port, the
>>>> IOT2040 has two of them. They can be told apart based on the board asset
>>>> tag in the DMI table.
> 
>>>> +       const char *asset_tag;
>>>
>>> I guess this is redundant. See below.
>>>
>>>> +       {
>>>> +               .name = "SIMATIC IOT2000",
>>>> +               .asset_tag = "6ES7647-0AA00-0YA2",
>>>> +               .func = 6,
>>>> +               .phy_addr = 1,
>>>> +       },
>>>
>>> The below has same definition disregard on asset_tag.
>>>
>>
>> There is a small difference in the asset tag, just not at the last digit
>> where one may expect it, look:
>>
>> ...-0YA2 -> IOT2020
>> ...-1YA2 -> IOT2040
> 
> Yes. And how does it change my statement? You may use one record here
> instead of two.

How? Please be more verbose in your comments.

> 
>>
>>>> +       {
>>>> +               .name = "SIMATIC IOT2000",
>>>> +               .asset_tag = "6ES7647-0AA00-1YA2",
>>>> +               .func = 6,
>>>> +               .phy_addr = 1,
>>>> +       },
> 
>>>> +       {
>>>> +               .name = "SIMATIC IOT2000",
>>>> +               .asset_tag = "6ES7647-0AA00-1YA2",
>>>> +               .func = 7,
>>>> +               .phy_addr = 1,
>>>> +       },
>>>
>>> How this supposed to work if phy_addr is the same?
>> That address space is MAC-local, and we have two different MACs here.
> 
> Got it, though asset_tag here is redundant as well.
> 

It's not as it is the only differentiating criteria to tell the
two-ports variant apart from the one-port (and to avoid confusing it
with any potential future variant). We could leave out the name, but I
kept it for documentation purposes.

Jan

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