ethtool: Add transceiver module extended state

Add an extended state and sub-state to describe link issues related to
transceiver modules.

The 'ETHTOOL_LINK_EXT_SUBSTATE_MODULE_CMIS_NOT_READY' extended sub-state
tells user space that port is unable to gain a carrier because the CMIS
Module State Machine did not reach the ModuleReady (Fully Operational)
state. For example, if the module is stuck at ModuleLowPwr or
ModuleFault state. In case of the latter, user space can read the fault
reason from the module's EEPROM and potentially reset it.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/networking/ethtool-netlink.rst

@@ -528,6 +528,8 @@ Link extended states:
                                                         power required from cable or module
 
   ``ETHTOOL_LINK_EXT_STATE_OVERHEAT``                   The module is overheated
+
+  ``ETHTOOL_LINK_EXT_STATE_MODULE``                     Transceiver module issue
   ================================================      ============================================
 
 Link extended substates:
@@ -621,6 +623,14 @@ Link extended substates:
   ``ETHTOOL_LINK_EXT_SUBSTATE_CI_CABLE_TEST_FAILURE``   Cable test failure
   ===================================================   ============================================
 
+  Transceiver module issue substates:
+
+  ===================================================   ============================================
+  ``ETHTOOL_LINK_EXT_SUBSTATE_MODULE_CMIS_NOT_READY``   The CMIS Module State Machine did not reach
+                                                        the ModuleReady state. For example, if the
+                                                        module is stuck at ModuleFault state
+  ===================================================   ============================================
+
 DEBUG_GET
 =========
 

include/linux/ethtool.h

@@ -94,6 +94,7 @@ struct ethtool_link_ext_state_info {
 		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;
+		enum ethtool_link_ext_substate_module module;
 		u8 __link_ext_substate;
 	};
 };

include/uapi/linux/ethtool.h

@@ -603,6 +603,7 @@ enum ethtool_link_ext_state {
 	ETHTOOL_LINK_EXT_STATE_CALIBRATION_FAILURE,
 	ETHTOOL_LINK_EXT_STATE_POWER_BUDGET_EXCEEDED,
 	ETHTOOL_LINK_EXT_STATE_OVERHEAT,
+	ETHTOOL_LINK_EXT_STATE_MODULE,
 };
 
 /* More information in addition to ETHTOOL_LINK_EXT_STATE_AUTONEG. */
@@ -649,6 +650,11 @@ enum ethtool_link_ext_substate_cable_issue {
 	ETHTOOL_LINK_EXT_SUBSTATE_CI_CABLE_TEST_FAILURE,
 };
 
+/* More information in addition to ETHTOOL_LINK_EXT_STATE_MODULE. */
+enum ethtool_link_ext_substate_module {
+	ETHTOOL_LINK_EXT_SUBSTATE_MODULE_CMIS_NOT_READY = 1,
+};
+
 #define ETH_GSTRING_LEN		32
 
 /**