Merge branch 'Add-ethtool-extended-link-state'

Ido Schimmel says:

====================
Add ethtool extended link state

Amit says:

Currently, device drivers can only indicate to user space if the network
link is up or down, without additional information.

This patch set provides an infrastructure that allows these drivers to
expose more information to user space about the link state. The
information can save users' time when trying to understand why a link is
not operationally up, for example.

The above is achieved by extending the existing ethtool LINKSTATE_GET
command with attributes that carry the extended state.

For example, no link due to missing cable:

$ ethtool ethX
...
Link detected: no (No cable)

Beside the general extended state, drivers can pass additional
information about the link state using the sub-state field. For example:

$ ethtool ethX
...
Link detected: no (Autoneg, No partner detected)

In the future the infrastructure can be extended - for example - to
allow PHY drivers to report whether a downshift to a lower speed
occurred. Something like:

$ ethtool ethX
...
Link detected: yes (downshifted)

Patch set overview:

Patches #1-#3 move mlxsw ethtool code to a separate file
Patches #4-#5 add the ethtool infrastructure for extended link state
Patches #6-#7 add support of extended link state in the mlxsw driver
Patches #8-#10 add test cases

Changes since v1:

* In documentation, show ETHTOOL_LINK_EXT_STATE_* and
  ETHTOOL_LINK_EXT_SUBSTATE_* constants instead of user-space strings
* Add `_CI_` to cable_issue substates to be consistent with
  other substates
* Keep the commit messages within 75 columns
* Use u8 variable for __link_ext_substate
* Document the meaning of -ENODATA in get_link_ext_state() callback
  description
* Do not zero data->link_ext_state_provided after getting an error
* Use `ret` variable for error value

Changes since RFC:

* Move documentation patch before ethtool patch
* Add nla_total_size() instead of sizeof() directly
* Return an error code from linkstate_get_ext_state()
* Remove SHORTED_CABLE, add CABLE_TEST_FAILURE instead
* Check if the interface is administratively up before setting ext_state
* Document all sub-states
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index a23b26eab479..48ad3b6a0150 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -86,6 +86,22 @@ struct net_device;
 u32 ethtool_op_get_link(struct net_device *dev);
 int ethtool_op_get_ts_info(struct net_device *dev, struct ethtool_ts_info *eti);
 
+
+/**
+ * struct ethtool_link_ext_state_info - link extended state and substate.
+ */
+struct ethtool_link_ext_state_info {
+	enum ethtool_link_ext_state link_ext_state;
+	union {
+		enum ethtool_link_ext_substate_autoneg autoneg;
+		enum ethtool_link_ext_substate_link_training link_training;
+		enum ethtool_link_ext_substate_link_logical_mismatch link_logical_mismatch;
+		enum ethtool_link_ext_substate_bad_signal_integrity bad_signal_integrity;
+		enum ethtool_link_ext_substate_cable_issue cable_issue;
+		u8 __link_ext_substate;
+	};
+};
+
 /**
  * ethtool_rxfh_indir_default - get default value for RX flow hash indirection
  * @index: Index in RX flow hash indirection table
@@ -245,6 +261,11 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
  * @get_link: Report whether physical link is up.  Will only be called if
  *	the netdev is up.  Should usually be set to ethtool_op_get_link(),
  *	which uses netif_carrier_ok().
+ * @get_link_ext_state: Report link extended state. Should set link_ext_state and
+ *	link_ext_substate (link_ext_substate of 0 means link_ext_substate is unknown,
+ *	do not attach ext_substate attribute to netlink message). If link_ext_state
+ *	and link_ext_substate are unknown, return -ENODATA. If not implemented,
+ *	link_ext_state and link_ext_substate will not be sent to userspace.
  * @get_eeprom: Read data from the device EEPROM.
  *	Should fill in the magic field.  Don't need to check len for zero
  *	or wraparound.  Fill in the data argument with the eeprom values
@@ -384,6 +405,8 @@ struct ethtool_ops {
 	void	(*set_msglevel)(struct net_device *, u32);
 	int	(*nway_reset)(struct net_device *);
 	u32	(*get_link)(struct net_device *);
+	int	(*get_link_ext_state)(struct net_device *,
+				      struct ethtool_link_ext_state_info *);
 	int	(*get_eeprom_len)(struct net_device *);
 	int	(*get_eeprom)(struct net_device *,
 			      struct ethtool_eeprom *, u8 *);