net: ethtool: add support for forward error correction modes
Forward Error Correction (FEC) modes i.e Base-R
and Reed-Solomon modes are introduced in 25G/40G/100G standards
for providing good BER at high speeds. Various networking devices
which support 25G/40G/100G provides ability to manage supported FEC
modes and the lack of FEC encoding control and reporting today is a
source for interoperability issues for many vendors.
FEC capability as well as specific FEC mode i.e. Base-R
or RS modes can be requested or advertised through bits D44:47 of
base link codeword.
This patch set intends to provide option under ethtool to manage
and report FEC encoding settings for networking devices as per
IEEE 802.3 bj, bm and by specs.
set-fec/show-fec option(s) are designed to provide control and
report the FEC encoding on the link.
SET FEC option:
root@tor: ethtool --set-fec swp1 encoding [off | RS | BaseR | auto]
Encoding: Types of encoding
Off : Turning off any encoding
RS : enforcing RS-FEC encoding on supported speeds
BaseR : enforcing Base R encoding on supported speeds
Auto : IEEE defaults for the speed/medium combination
Here are a few examples of what we would expect if encoding=auto:
- if autoneg is on, we are expecting FEC to be negotiated as on or off
as long as protocol supports it
- if the hardware is capable of detecting the FEC encoding on it's
receiver it will reconfigure its encoder to match
- in absence of the above, the configuration would be set to IEEE
defaults.
>From our understanding , this is essentially what most hardware/driver
combinations are doing today in the absence of a way for users to
control the behavior.
SHOW FEC option:
root@tor: ethtool --show-fec swp1
FEC parameters for swp1:
Active FEC encodings: RS
Configured FEC encodings: RS | BaseR
ETHTOOL DEVNAME output modification:
ethtool devname output:
root@tor:~# ethtool swp1
Settings for swp1:
root@hpe-7712-03:~# ethtool swp18
Settings for swp18:
Supported ports: [ FIBRE ]
Supported link modes: 40000baseCR4/Full
40000baseSR4/Full
40000baseLR4/Full
100000baseSR4/Full
100000baseCR4/Full
100000baseLR4_ER4/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Supported FEC modes: [RS | BaseR | None | Not reported]
Advertised link modes: Not reported
Advertised pause frame use: No
Advertised auto-negotiation: No
Advertised FEC modes: [RS | BaseR | None | Not reported]
<<<< One or more FEC modes
Speed: 100000Mb/s
Duplex: Full
Port: FIBRE
PHYAD: 106
Transceiver: internal
Auto-negotiation: off
Link detected: yes
This patch includes following changes
a) New ETHTOOL_SFECPARAM/SFECPARAM API, handled by
the new get_fecparam/set_fecparam callbacks, provides support
for configuration of forward error correction modes.
b) Link mode bits for FEC modes i.e. None (No FEC mode), RS, BaseR/FC
are defined so that users can configure these fec modes for supported
and advertising fields as part of link autonegotiation.
Signed-off-by: Vidya Sagar Ravipati <vidya.chowdary@gmail.com>
Signed-off-by: Dustin Byford <dustin@cumulusnetworks.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
3 files changed