Re: [PATCH 1/1] add ethtool loopback support

[Laurent Chavey <chavey@google.com>]

On Thu, Apr 8, 2010 at 11:29 AM, Ben Hutchings
<bhutchings@solarflare.com> wrote:
> On Thu, 2010-04-08 at 10:35 -0700, chavey@google.com wrote:
>> From: Ranjit Manomohan <ranjitm@google.com>
>> Date: Wed, 7 Apr 2010 15:19:48 -0700
>>
>> Add an ethtool option to use internal loopback mode for testing.
>> This feature is used for component and driver test coverage by putting
>> the device in hardware loopback mode and sending / receiving network
>> traffic from a user application to test the hardware and driver
>> transmit / receive paths.
>>
>> Signed-off-by: laurent chavey <chavey@google.com>
>> ---
>>  include/linux/ethtool.h |   16 ++++++++++++++++
>>  net/core/ethtool.c      |   40 ++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 56 insertions(+), 0 deletions(-)
>>
>> diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
>> index b33f316..df1dcc7 100644
>> --- a/include/linux/ethtool.h
>> +++ b/include/linux/ethtool.h
>> @@ -292,6 +292,18 @@ struct ethtool_stats {
>>       __u64   data[0];
>>  };
>>
>> +/* for setting the NIC into loopback mode */
>> +struct ethtool_loopback {
>> +     u32 cmd;                /* ETHTOOL_SLOOPBACK */
>> +     u32 type;               /* ethtool_loopback_type */
>> +};
>> +
>> +enum ethtool_loopback_type {
>> +     ETH_MAC                 = 0x00000001,
>> +     ETH_PHY_INT             = 0x00000002,
>> +     ETH_PHY_EXT             = 0x00000004
>> +};
> [...]
>
> There are many different places you can loop back within a MAC or PHY,
> not to mention bypassing the MAC altogether.  See
> drivers/net/sfc/mcdi_pcol.h, starting from the line
> '#define MC_CMD_LOOPBACK_NONE 0'.  I believe we implement all of those
> loopback modes on at least one board.
>
> Also are these supposed to be an enumeration or flags?  In theory you
those are enums that can be or together.
> could use wire-side and host-side loopback at the same time if they
> don't overlap, but it's probably too much trouble to bother with.  Any
> other combination is meaningless.

>
> Ben.
>
> --
> Ben Hutchings, Senior Software Engineer, Solarflare Communications
> Not speaking for my employer; that's the marketing department's job.
> They asked us to note that Solarflare product names are trademarked.
>
>