* [RFC PATCH v2] net: ethtool: add support for forward error correction modes
@ 2017-02-10 11:43 Vidya Sagar Ravipati
2017-02-15 17:38 ` Casey Leedom
0 siblings, 1 reply; 2+ messages in thread
From: Vidya Sagar Ravipati @ 2017-02-10 11:43 UTC (permalink / raw)
To: netdev, leedom, linville, jeffrey.t.kirsher, davem
Cc: roopa, dustin, odedw, ariela, Yuval.Mintz, galp, vidya.chowdary
From: Vidya Sagar Ravipati <vidya@cumulusnetworks.com>
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 itneroperability 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@cumulusnetworks.com>
---
include/linux/ethtool.h | 4 ++++
include/uapi/linux/ethtool.h | 48 +++++++++++++++++++++++++++++++++++++++++++-
net/core/ethtool.c | 34 +++++++++++++++++++++++++++++++
3 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 9ded8c6..79a0bab 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -372,5 +372,9 @@ struct ethtool_ops {
struct ethtool_link_ksettings *);
int (*set_link_ksettings)(struct net_device *,
const struct ethtool_link_ksettings *);
+ int (*get_fecparam)(struct net_device *,
+ struct ethtool_fecparam *);
+ int (*set_fecparam)(struct net_device *,
+ struct ethtool_fecparam *);
};
#endif /* _LINUX_ETHTOOL_H */
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 3dc91a4..a7ab49e 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -1238,6 +1238,47 @@ struct ethtool_per_queue_op {
char data[];
};
+/**
+ * struct ethtool_fecparam - Ethernet forward error correction(fec) parameters
+ * @cmd: Command number = %ETHTOOL_GFECPARAM or %ETHTOOL_SFECPARAM
+ * @active_fec: FEC mode which is active on porte
+ * @fec: Bitmask of supported/configured FEC modes
+ * @rsvd: Reserved for future extensions. i.e FEC bypass feature.
+ *
+ * Drivers should reject a non-zero setting of @autoneg when
+ * autoneogotiation is disabled (or not supported) for the link.
+ *
+ */
+struct ethtool_fecparam {
+ __u32 cmd;
+ /* bitmask of FEC modes */
+ __u32 active_fec;
+ __u32 fec;
+ __u32 reserved;
+};
+
+/**
+ * enum ethtool_fec_config_bits - flags definition of ethtool_fec_configuration
+ * @ETHTOOL_FEC_NONE: FEC mode configuration is not supported
+ * @ETHTOOL_FEC_AUTO: Default/Best FEC mode provided by driver
+ * @ETHTOOL_FEC_OFF: No FEC Mode
+ * @ETHTOOL_FEC_RS: Reed-Solomon Forward Error Detection mode
+ * @ETHTOOL_FEC_BASER: Base-R/Reed-Solomon Forward Error Detection mode
+ */
+enum ethtool_fec_config_bits {
+ ETHTOOL_FEC_NONE_BIT,
+ ETHTOOL_FEC_AUTO_BIT,
+ ETHTOOL_FEC_OFF_BIT,
+ ETHTOOL_FEC_RS_BIT,
+ ETHTOOL_FEC_BASER_BIT,
+};
+
+#define ETHTOOL_FEC_NONE (1 << ETHTOOL_FEC_NONE_BIT)
+#define ETHTOOL_FEC_AUTO (1 << ETHTOOL_FEC_AUTO_BIT)
+#define ETHTOOL_FEC_OFF (1 << ETHTOOL_FEC_OFF_BIT)
+#define ETHTOOL_FEC_RS (1 << ETHTOOL_FEC_RS_BIT)
+#define ETHTOOL_FEC_BASER (1 << ETHTOOL_FEC_BASER_BIT)
+
/* CMDs currently supported */
#define ETHTOOL_GSET 0x00000001 /* DEPRECATED, Get settings.
* Please use ETHTOOL_GLINKSETTINGS
@@ -1330,6 +1371,8 @@ struct ethtool_per_queue_op {
#define ETHTOOL_SLINKSETTINGS 0x0000004d /* Set ethtool_link_settings */
#define ETHTOOL_PHY_GTUNABLE 0x0000004e /* Get PHY tunable configuration */
#define ETHTOOL_PHY_STUNABLE 0x0000004f /* Set PHY tunable configuration */
+#define ETHTOOL_GFECPARAM 0x0000004e /* Get FEC settings */
+#define ETHTOOL_SFECPARAM 0x0000004f /* Set FEC settings */
/* compatibility with older code */
#define SPARC_ETH_GSET ETHTOOL_GSET
@@ -1387,6 +1430,9 @@ enum ethtool_link_mode_bit_indices {
ETHTOOL_LINK_MODE_2500baseT_Full_BIT = 47,
ETHTOOL_LINK_MODE_5000baseT_Full_BIT = 48,
+ ETHTOOL_LINK_MODE_FEC_NONE_BIT = 49,
+ ETHTOOL_LINK_MODE_FEC_RS_BIT = 50,
+ ETHTOOL_LINK_MODE_FEC_BASER_BIT = 51,
/* Last allowed bit for __ETHTOOL_LINK_MODE_LEGACY_MASK is bit
* 31. Please do NOT define any SUPPORTED_* or ADVERTISED_*
@@ -1395,7 +1441,7 @@ enum ethtool_link_mode_bit_indices {
*/
__ETHTOOL_LINK_MODE_LAST
- = ETHTOOL_LINK_MODE_5000baseT_Full_BIT,
+ = ETHTOOL_LINK_MODE_FEC_BASER_BIT,
};
#define __ETHTOOL_LINK_MODE_LEGACY_MASK(base_name) \
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index be7bab1..98fd78c 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -2519,6 +2519,33 @@ static int set_phy_tunable(struct net_device *dev, void __user *useraddr)
return ret;
}
+static int ethtool_get_fecparam(struct net_device *dev, void __user *useraddr)
+{
+ struct ethtool_fecparam fecparam = { ETHTOOL_GFECPARAM };
+
+ if (!dev->ethtool_ops->get_fecparam)
+ return -EOPNOTSUPP;
+
+ dev->ethtool_ops->get_fecparam(dev, &fecparam);
+
+ if (copy_to_user(useraddr, &fecparam, sizeof(fecparam)))
+ return -EFAULT;
+ return 0;
+}
+
+static int ethtool_set_fecparam(struct net_device *dev, void __user *useraddr)
+{
+ struct ethtool_fecparam fecparam;
+
+ if (!dev->ethtool_ops->set_fecparam)
+ return -EOPNOTSUPP;
+
+ if (copy_from_user(&fecparam, useraddr, sizeof(fecparam)))
+ return -EFAULT;
+
+ return dev->ethtool_ops->set_fecparam(dev, &fecparam);
+}
+
/* The main entry point in this file. Called from net/core/dev_ioctl.c */
int dev_ethtool(struct net *net, struct ifreq *ifr)
@@ -2578,6 +2605,7 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
case ETHTOOL_GTUNABLE:
case ETHTOOL_PHY_GTUNABLE:
case ETHTOOL_GLINKSETTINGS:
+ case ETHTOOL_GFECPARAM:
break;
default:
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
@@ -2789,6 +2817,12 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
case ETHTOOL_PHY_STUNABLE:
rc = set_phy_tunable(dev, useraddr);
break;
+ case ETHTOOL_GFECPARAM:
+ rc = ethtool_get_fecparam(dev, useraddr);
+ break;
+ case ETHTOOL_SFECPARAM:
+ rc = ethtool_set_fecparam(dev, useraddr);
+ break;
default:
rc = -EOPNOTSUPP;
}
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [RFC PATCH v2] net: ethtool: add support for forward error correction modes
2017-02-10 11:43 [RFC PATCH v2] net: ethtool: add support for forward error correction modes Vidya Sagar Ravipati
@ 2017-02-15 17:38 ` Casey Leedom
0 siblings, 0 replies; 2+ messages in thread
From: Casey Leedom @ 2017-02-15 17:38 UTC (permalink / raw)
To: Vidya Sagar Ravipati, netdev, linville, jeffrey.t.kirsher, davem
Cc: roopa, dustin, odedw, ariela, Yuval.Mintz, galp, vidya.chowdary
Vidya and I have been in communication on how to support Forward Error Correction Management on Links. My own thoughts are that we should consider using the new Get/Set Link Ksettiongs API because FEC is a low-level Link parameter which is either negotiated at the same time as Link Speed if Auto-Negotiation is in use, or must be set identically on both Link Peers is AN is not in use. I'm not convinced that FEC Management should use a separate ethtool/Kernel Driver API ala Pause Frame settings.
I'm hoping to meet with Vidya and his collaborators at Cumulus Networks in the very near term to hash these issues out.
Casey
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2017-02-10 11:43 [RFC PATCH v2] net: ethtool: add support for forward error correction modes Vidya Sagar Ravipati
2017-02-15 17:38 ` Casey Leedom
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