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>

Documentation/networking/ethtool-netlink.rst

@@ -443,10 +443,11 @@ supports.
 LINKSTATE_GET
 =============
 
-Requests link state information. At the moment, only link up/down flag (as
-provided by ``ETHTOOL_GLINK`` ioctl command) is provided but some future
-extensions are planned (e.g. link down reason). This request does not have any
-attributes.
+Requests link state information. Link up/down flag (as provided by
+``ETHTOOL_GLINK`` ioctl command) is provided. Optionally, extended state might
+be provided as well. In general, extended state describes reasons for why a port
+is down, or why it operates in some non-obvious mode. This request does not have
+any attributes.
 
 Request contents:
 
@@ -461,16 +462,135 @@ Kernel response contents:
   ``ETHTOOL_A_LINKSTATE_LINK``          bool    link state (up/down)
   ``ETHTOOL_A_LINKSTATE_SQI``           u32     Current Signal Quality Index
   ``ETHTOOL_A_LINKSTATE_SQI_MAX``       u32     Max support SQI value
+  ``ETHTOOL_A_LINKSTATE_EXT_STATE``     u8      link extended state
+  ``ETHTOOL_A_LINKSTATE_EXT_SUBSTATE``  u8      link extended substate
   ====================================  ======  ============================
 
 For most NIC drivers, the value of ``ETHTOOL_A_LINKSTATE_LINK`` returns
 carrier flag provided by ``netif_carrier_ok()`` but there are drivers which
 define their own handler.
 
+``ETHTOOL_A_LINKSTATE_EXT_STATE`` and ``ETHTOOL_A_LINKSTATE_EXT_SUBSTATE`` are
+optional values. ethtool core can provide either both
+``ETHTOOL_A_LINKSTATE_EXT_STATE`` and ``ETHTOOL_A_LINKSTATE_EXT_SUBSTATE``,
+or only ``ETHTOOL_A_LINKSTATE_EXT_STATE``, or none of them.
+
 ``LINKSTATE_GET`` allows dump requests (kernel returns reply messages for all
 devices supporting the request).
 
 
+Link extended states:
+
+  ================================================      ============================================
+  ``ETHTOOL_LINK_EXT_STATE_AUTONEG``                    States relating to the autonegotiation or
+                                                        issues therein
+
+  ``ETHTOOL_LINK_EXT_STATE_LINK_TRAINING_FAILURE``      Failure during link training
+
+  ``ETHTOOL_LINK_EXT_STATE_LINK_LOGICAL_MISMATCH``      Logical mismatch in physical coding sublayer
+                                                        or forward error correction sublayer
+
+  ``ETHTOOL_LINK_EXT_STATE_BAD_SIGNAL_INTEGRITY``       Signal integrity issues
+
+  ``ETHTOOL_LINK_EXT_STATE_NO_CABLE``                   No cable connected
+
+  ``ETHTOOL_LINK_EXT_STATE_CABLE_ISSUE``                Failure is related to cable,
+                                                        e.g., unsupported cable
+
+  ``ETHTOOL_LINK_EXT_STATE_EEPROM_ISSUE``               Failure is related to EEPROM, e.g., failure
+                                                        during reading or parsing the data
+
+  ``ETHTOOL_LINK_EXT_STATE_CALIBRATION_FAILURE``        Failure during calibration algorithm
+
+  ``ETHTOOL_LINK_EXT_STATE_POWER_BUDGET_EXCEEDED``      The hardware is not able to provide the
+                                                        power required from cable or module
+
+  ``ETHTOOL_LINK_EXT_STATE_OVERHEAT``                   The module is overheated
+  =================================================     ============================================
+
+Link extended substates:
+
+  Autoneg substates:
+
+  ==============================================================    ================================
+  ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NO_PARTNER_DETECTED``              Peer side is down
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_AN_ACK_NOT_RECEIVED``                 Ack not received from peer side
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NEXT_PAGE_EXCHANGE_FAILED``        Next page exchange failed
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NO_PARTNER_DETECTED_FORCE_MODE``   Peer side is down during force
+                                                                    mode or there is no agreement of
+                                                                    speed
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_AN_FEC_MISMATCH_DURING_OVERRIDE``     Forward error correction modes
+                                                                    in both sides are mismatched
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_AN_NO_HCD``                           No Highest Common Denominator
+  ==============================================================    ================================
+
+  Link training substates:
+
+  ==========================================================================    ====================
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LT_KR_FRAME_LOCK_NOT_ACQUIRED``                    Frames were not
+                                                                                 recognized, the
+                                                                                 lock failed
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LT_KR_LINK_INHIBIT_TIMEOUT``                       The lock did not
+                                                                                 occur before
+                                                                                 timeout
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LT_KR_LINK_PARTNER_DID_NOT_SET_RECEIVER_READY``    Peer side did not
+                                                                                 send ready signal
+                                                                                 after training
+                                                                                 process
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LT_REMOTE_FAULT``                                  Remote side is not
+                                                                                 ready yet
+  ==========================================================================    ====================
+
+  Link logical mismatch substates:
+
+  ===============================================================    ===============================
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_PCS_DID_NOT_ACQUIRE_BLOCK_LOCK``   Physical coding sublayer was
+                                                                     not locked in first phase -
+                                                                     block lock
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_PCS_DID_NOT_ACQUIRE_AM_LOCK``      Physical coding sublayer was
+                                                                     not locked in second phase -
+                                                                     alignment markers lock
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_PCS_DID_NOT_GET_ALIGN_STATUS``     Physical coding sublayer did
+                                                                     not get align status
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_FC_FEC_IS_NOT_LOCKED``             FC forward error correction is
+                                                                     not locked
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_LLM_RS_FEC_IS_NOT_LOCKED``             RS forward error correction is
+                                                                     not locked
+  ===============================================================    ===============================
+
+  Bad signal integrity substates:
+
+  =================================================================    =============================
+  ``ETHTOOL_LINK_EXT_SUBSTATE_BSI_LARGE_NUMBER_OF_PHYSICAL_ERRORS``    Large number of physical
+                                                                       errors
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_BSI_UNSUPPORTED_RATE``                   The system attempted to
+                                                                       operate the cable at a rate
+                                                                       that is not formally
+                                                                       supported, which led to
+                                                                       signal integrity issues
+  =================================================================    =============================
+
+  Cable issue substates:
+
+  ==================================================    ============================================
+  ``ETHTOOL_LINK_EXT_SUBSTATE_CI_UNSUPPORTED_CABLE``    Unsupported cable
+
+  ``ETHTOOL_LINK_EXT_SUBSTATE_CI_CABLE_TEST_FAILURE``   Cable test failure
+  ==================================================    ============================================
+
 DEBUG_GET
 =========
 

drivers/net/ethernet/mellanox/mlxsw/Makefile

@@ -30,7 +30,8 @@ mlxsw_spectrum-objs		:= spectrum.o spectrum_buffers.o \
 				   spectrum_mr_tcam.o spectrum_mr.o \
 				   spectrum_qdisc.o spectrum_span.o \
 				   spectrum_nve.o spectrum_nve_vxlan.o \
-				   spectrum_dpipe.o spectrum_trap.o
+				   spectrum_dpipe.o spectrum_trap.o \
+				   spectrum_ethtool.o
 mlxsw_spectrum-$(CONFIG_MLXSW_SPECTRUM_DCB)	+= spectrum_dcb.o
 mlxsw_spectrum-$(CONFIG_PTP_1588_CLOCK)		+= spectrum_ptp.o
 obj-$(CONFIG_MLXSW_MINIMAL)	+= mlxsw_minimal.o

drivers/net/ethernet/mellanox/mlxsw/reg.h

@@ -5438,6 +5438,56 @@ static inline void mlxsw_reg_pplr_pack(char *payload, u8 local_port,
 				 MLXSW_REG_PPLR_LB_TYPE_BIT_PHY_LOCAL : 0);
 }
 
+/* PDDR - Port Diagnostics Database Register
+ * -----------------------------------------
+ * The PDDR enables to read the Phy debug database
+ */
+#define MLXSW_REG_PDDR_ID 0x5031
+#define MLXSW_REG_PDDR_LEN 0x100
+
+MLXSW_REG_DEFINE(pddr, MLXSW_REG_PDDR_ID, MLXSW_REG_PDDR_LEN);
+
+/* reg_pddr_local_port
+ * Local port number.
+ * Access: Index
+ */
+MLXSW_ITEM32(reg, pddr, local_port, 0x00, 16, 8);
+
+enum mlxsw_reg_pddr_page_select {
+	MLXSW_REG_PDDR_PAGE_SELECT_TROUBLESHOOTING_INFO = 1,
+};
+
+/* reg_pddr_page_select
+ * Page select index.
+ * Access: Index
+ */
+MLXSW_ITEM32(reg, pddr, page_select, 0x04, 0, 8);
+
+enum mlxsw_reg_pddr_trblsh_group_opcode {
+	/* Monitor opcodes */
+	MLXSW_REG_PDDR_TRBLSH_GROUP_OPCODE_MONITOR,
+};
+
+/* reg_pddr_group_opcode
+ * Group selector.
+ * Access: Index
+ */
+MLXSW_ITEM32(reg, pddr, trblsh_group_opcode, 0x08, 0, 16);
+
+/* reg_pddr_status_opcode
+ * Group selector.
+ * Access: RO
+ */
+MLXSW_ITEM32(reg, pddr, trblsh_status_opcode, 0x0C, 0, 16);
+
+static inline void mlxsw_reg_pddr_pack(char *payload, u8 local_port,
+				       u8 page_select)
+{
+	MLXSW_REG_ZERO(pddr, payload);
+	mlxsw_reg_pddr_local_port_set(payload, local_port);
+	mlxsw_reg_pddr_page_select_set(payload, page_select);
+}
+
 /* PMTM - Port Module Type Mapping Register
  * ----------------------------------------
  * The PMTM allows query or configuration of module types.
@@ -10758,6 +10808,7 @@ static const struct mlxsw_reg_info *mlxsw_reg_infos[] = {
 	MLXSW_REG(pbmc),
 	MLXSW_REG(pspa),
 	MLXSW_REG(pplr),
+	MLXSW_REG(pddr),
 	MLXSW_REG(pmtm),
 	MLXSW_REG(htgt),
 	MLXSW_REG(hpkt),