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Message-ID: <CAGVrzcYnLjRRfakaEsJvHGdEEJrD5xpgBu4D9qOX4iYac+i=YA@mail.gmail.com>
Date: Wed, 25 Sep 2013 09:24:34 +0100
From: Florian Fainelli <f.fainelli@...il.com>
To: Gary Thomas <gary@...assoc.com>
Cc: Ben Hutchings <bhutchings@...arflare.com>,
netdev <netdev@...r.kernel.org>
Subject: Re: SMSC 9303 support
2013/9/24 Gary Thomas <gary@...assoc.com>:
> On 2013-09-24 12:29, Florian Fainelli wrote:
>>
>> Hello,
>>
>> 2013/9/24 Gary Thomas <gary@...assoc.com>:
>>>
>>> On 2013-09-24 10:51, Ben Hutchings wrote:
>>>>
>>>>
>>>> On Tue, 2013-09-24 at 06:21 -0600, Gary Thomas wrote:
>>>>>
>>>>>
>>>>> I need to support the SMSC9303 in an embedded system. I'm not
>>>>> finding any [explicit] support for this device in the latest
>>>>> mainline kernel. Did I miss something?
>>>>>
>>>>> To be clear, the SMSC9303 is a 3-port managed ethernet switch
>>>>> capable of supporting 802.1D/802.1Q directly. This switch is
>>>>> driven by a single MAC via MII/RMII and exposes the other two
>>>>> ports via physical PHYs. What I need it to do is behave like
>>>>> two external, separate devices. I was thinking that what I need
>>>>> to do is treat these as VLAN devices since the switch can manage
>>>>> the routing.
>>>>>
>>>>> Does this seem like a reasonable approach?
>>>>
>>>>
>>>>
>>>> Linux has 'DSA' (Distributed Switch Architecture) which supports tagging
>>>> of packets to indicate which switch port they are sent or received
>>>> through. This was originally added to support some Marvell switch chips
>>>> and I don't know whether it would be suitable or extensible for this
>>>> one.
>>>
>>>
>>>
>>> I've used the DSA stuff for years (worked directly with the Marvell folks
>>> when it was being developed). It might work for this device, I'll think
>>> some more about using it although I was hoping for a lighter weight
>>> solution.
>>
>>
>> I do not think DSA is suitable for pure 802.1q switches such as this
>> one. OpenWrt has an out of tree patch which adds some switch-specific
>> operations that can be controlled over netlink (currently trying to
>> get them in a shape where they can be submitted for mainline
>> inclusion) [1], which I think is much more suitable than DSA or any
>> other proprietary switch tagging mechanism.
>>
>> [1]:
>> https://dev.openwrt.org/browser/trunk/target/linux/generic/files/drivers/net/phy/swconfig.c
>>
>
> This looks interesting. Do you have any more information on how to
> integrate this and/or use it?
Here are a couple of drivers that implement these "switch ops", my
favorite being b53 because it shows nicely how SPI, MDIO or MMIO
switch can be supported within the same core:
https://dev.openwrt.org/browser/trunk/target/linux/generic/files/drivers/net/phy/b53
adm6996 is also pretty straight forward:
https://dev.openwrt.org/browser/trunk/target/linux/generic/files/drivers/net/phy/adm6996.c
and here is the user-space command line tool to query/control these
(needs libnl):
https://dev.openwrt.org/browser/trunk/package/network/config/swconfig/src
--
Florian
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