Extend the ethtool netlink cable testing interface by adding support for
specifying the source of cable testing results. This allows users to
differentiate between results obtained through different diagnostic
methods.

For example, some TI 10BaseT1L PHYs provide two variants of cable
diagnostics: Time Domain Reflectometry (TDR) and Active Link Cable
Diagnostic (ALCD). By introducing `ETHTOOL_A_CABLE_RESULT_SRC` and
`ETHTOOL_A_CABLE_FAULT_LENGTH_SRC` attributes, this update enables
drivers to indicate whether the result was derived from TDR or ALCD,
improving the clarity and utility of diagnostic information.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
changes v2:
- update Documentation/netlink/specs/ethtool.yaml
- use u8 instead of u32 for _src
- update comments
---
 Documentation/netlink/specs/ethtool.yaml     |  6 ++++++
 Documentation/networking/ethtool-netlink.rst |  5 +++++
 include/uapi/linux/ethtool_netlink.h         | 11 +++++++++++
 3 files changed, 22 insertions(+)

diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
index 1bbeaba5c6442..af999ccd0adf8 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml
@@ -659,6 +659,9 @@ attribute-sets:
       -
         name: code
         type: u8
+      -
+        name: src
+        type: u8
   -
     name: cable-fault-length
     attributes:
@@ -668,6 +671,9 @@ attribute-sets:
       -
         name: cm
         type: u32
+      -
+        name: src
+        type: u8
   -
     name: cable-nest
     attributes:
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index 3f6c6880e7c48..295e75619abdf 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -1307,12 +1307,17 @@ information.
  +-+-+-----------------------------------------+--------+---------------------+
  | | | ``ETHTOOL_A_CABLE_RESULTS_CODE``        | u8     | result code         |
  +-+-+-----------------------------------------+--------+---------------------+
+ | | | ``ETHTOOL_A_CABLE_RESULT_SRC``          | u8     | information source  |
+ +-+-+-----------------------------------------+--------+---------------------+
  | | ``ETHTOOL_A_CABLE_NEST_FAULT_LENGTH``     | nested | cable length        |
  +-+-+-----------------------------------------+--------+---------------------+
  | | | ``ETHTOOL_A_CABLE_FAULT_LENGTH_PAIR``   | u8     | pair number         |
  +-+-+-----------------------------------------+--------+---------------------+
  | | | ``ETHTOOL_A_CABLE_FAULT_LENGTH_CM``     | u32    | length in cm        |
  +-+-+-----------------------------------------+--------+---------------------+
+ | | | ``ETHTOOL_A_CABLE_FAULT_LENGTH_SRC``    | u8     | information source  |
+ +-+-+-----------------------------------------+--------+---------------------+
+
 
 CABLE_TEST TDR
 ==============
diff --git a/include/uapi/linux/ethtool_netlink.h b/include/uapi/linux/ethtool_netlink.h
index 9074fa309bd6d..445e2d434686f 100644
--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h
@@ -569,10 +569,20 @@ enum {
 	ETHTOOL_A_CABLE_PAIR_D,
 };
 
+/* Information source for specific results. */
+enum {
+	ETHTOOL_A_CABLE_INF_SRC_UNSPEC,
+	/* Results provided by the Time Domain Reflectometry (TDR) */
+	ETHTOOL_A_CABLE_INF_SRC_TDR,
+	/* Results provided by the Active Link Cable Diagnostic (ALCD) */
+	ETHTOOL_A_CABLE_INF_SRC_ALCD,
+};
+
 enum {
 	ETHTOOL_A_CABLE_RESULT_UNSPEC,
 	ETHTOOL_A_CABLE_RESULT_PAIR,		/* u8 ETHTOOL_A_CABLE_PAIR_ */
 	ETHTOOL_A_CABLE_RESULT_CODE,		/* u8 ETHTOOL_A_CABLE_RESULT_CODE_ */
+	ETHTOOL_A_CABLE_RESULT_SRC,		/* u8 ETHTOOL_A_CABLE_INF_SRC_ */
 
 	__ETHTOOL_A_CABLE_RESULT_CNT,
 	ETHTOOL_A_CABLE_RESULT_MAX = (__ETHTOOL_A_CABLE_RESULT_CNT - 1)
@@ -582,6 +592,7 @@ enum {
 	ETHTOOL_A_CABLE_FAULT_LENGTH_UNSPEC,
 	ETHTOOL_A_CABLE_FAULT_LENGTH_PAIR,	/* u8 ETHTOOL_A_CABLE_PAIR_ */
 	ETHTOOL_A_CABLE_FAULT_LENGTH_CM,	/* u32 */
+	ETHTOOL_A_CABLE_FAULT_LENGTH_SRC,	/* u8 ETHTOOL_A_CABLE_INF_SRC_ */
 
 	__ETHTOOL_A_CABLE_FAULT_LENGTH_CNT,
 	ETHTOOL_A_CABLE_FAULT_LENGTH_MAX = (__ETHTOOL_A_CABLE_FAULT_LENGTH_CNT - 1)
-- 
2.39.2

On Tue, 20 Aug 2024 12:12:54 +0200 Oleksij Rempel wrote:
> +      -
> +        name: src
> +        type: u8

If you have to respin please s/u8/u32/

Netlink rounds up all fields sizes to u32, u8 ends up being the same
size as u32 "on the wire" but 3 out of the 4 bytes are unusable.

On Tue, Aug 20, 2024 at 12:12:54PM +0200, Oleksij Rempel wrote:
> Extend the ethtool netlink cable testing interface by adding support for
> specifying the source of cable testing results. This allows users to
> differentiate between results obtained through different diagnostic
> methods.
> 
> For example, some TI 10BaseT1L PHYs provide two variants of cable
> diagnostics: Time Domain Reflectometry (TDR) and Active Link Cable
> Diagnostic (ALCD). By introducing `ETHTOOL_A_CABLE_RESULT_SRC` and
> `ETHTOOL_A_CABLE_FAULT_LENGTH_SRC` attributes, this update enables
> drivers to indicate whether the result was derived from TDR or ALCD,
> improving the clarity and utility of diagnostic information.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew