[RFC net-next 1/4] ethtool: module: Define CMIS loopback YAML spec and UAPI

[Björn Töpel]

Add the netlink YAML specification for module loopback attributes used
to query and control diagnostic loopback modes on CMIS-compliant
transceiver modules.

Define the module-loopback-types flags enum with four loopback types
from CMIS 5.2 Section 8.4.11 ("Diagnostic Loopback Capabilities"):
  - media-side-output (Rx to Tx)
  - media-side-input  (Tx to Rx)
  - host-side-output  (Rx to Tx)
  - host-side-input   (Tx to Rx)

Add two new attributes to the module attribute-set:
  - loopback-capabilities: bitmask of supported loopback types
  - loopback-enabled:      bitmask of currently enabled loopback types

Include both attributes in the module-get reply (and by YAML anchor
reuse, in the module-set request). Regenerate the UAPI header.

Signed-off-by: Björn Töpel <bjorn@xxxxxxxxxx>
---
 Documentation/netlink/specs/ethtool.yaml      | 27 +++++++++++++++++++
 .../uapi/linux/ethtool_netlink_generated.h    | 22 +++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml
index 0a2d2343f79a..88dfd5f05b3c 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml
@@ -11,6 +11,23 @@ c-family-name: ethtool-genl-name
 c-version-name: ethtool-genl-version
 
 definitions:
+  -
+    name: module-loopback-types
+    type: flags
+    doc: Defines the loopback types (host/electrical or media/optical side) and the signal's path direction (input/near-end or output/far-end).
+    entries:
+      -
+        name: media-side-output
+        doc: Media Side Output Loopback (Rx to Tx)
+      -
+        name: media-side-input
+        doc: Media Side Input Loopback (Tx to Rx)
+      -
+        name: host-side-output
+        doc: Host Side Output Loopback (Rx to Tx)
+      -
+        name: host-side-input
+        doc: Host Side Input Loopback (Tx to Rx)
   -
     name: udp-tunnel-type
     enum-name:
@@ -1438,6 +1455,14 @@ attribute-sets:
       -
         name: power-mode
         type: u8
+      -
+        name: loopback-capabilities
+        type: uint
+        enum: module-loopback-types
+      -
+        name: loopback-enabled
+        type: uint
+        enum: module-loopback-types
   -
     name: c33-pse-pw-limit
     attr-cnt-name: __ethtool-a-c33-pse-pw-limit-cnt
@@ -2501,6 +2526,8 @@ operations:
             - header
             - power-mode-policy
             - power-mode
+            - loopback-capabilities
+            - loopback-enabled
       dump: *module-get-op
     -
       name: module-set
diff --git a/include/uapi/linux/ethtool_netlink_generated.h b/include/uapi/linux/ethtool_netlink_generated.h
index 556a0c834df5..d94b75b27718 100644
--- a/include/uapi/linux/ethtool_netlink_generated.h
+++ b/include/uapi/linux/ethtool_netlink_generated.h
@@ -10,6 +10,26 @@
 #define ETHTOOL_GENL_NAME	"ethtool"
 #define ETHTOOL_GENL_VERSION	1
 
+/**
+ * enum ethtool_module_loopback_types - Defines the loopback types
+ *   (host/electrical or media/optical side) and the signal's path direction
+ *   (input/near-end or output/far-end).
+ * @ETHTOOL_MODULE_LOOPBACK_TYPES_MEDIA_SIDE_OUTPUT: Media Side Output Loopback
+ *   (Rx to Tx)
+ * @ETHTOOL_MODULE_LOOPBACK_TYPES_MEDIA_SIDE_INPUT: Media Side Input Loopback
+ *   (Tx to Rx)
+ * @ETHTOOL_MODULE_LOOPBACK_TYPES_HOST_SIDE_OUTPUT: Host Side Output Loopback
+ *   (Rx to Tx)
+ * @ETHTOOL_MODULE_LOOPBACK_TYPES_HOST_SIDE_INPUT: Host Side Input Loopback (Tx
+ *   to Rx)
+ */
+enum ethtool_module_loopback_types {
+	ETHTOOL_MODULE_LOOPBACK_TYPES_MEDIA_SIDE_OUTPUT = 1,
+	ETHTOOL_MODULE_LOOPBACK_TYPES_MEDIA_SIDE_INPUT = 2,
+	ETHTOOL_MODULE_LOOPBACK_TYPES_HOST_SIDE_OUTPUT = 4,
+	ETHTOOL_MODULE_LOOPBACK_TYPES_HOST_SIDE_INPUT = 8,
+};
+
 enum {
 	ETHTOOL_UDP_TUNNEL_TYPE_VXLAN,
 	ETHTOOL_UDP_TUNNEL_TYPE_GENEVE,
@@ -654,6 +674,8 @@ enum {
 	ETHTOOL_A_MODULE_HEADER,
 	ETHTOOL_A_MODULE_POWER_MODE_POLICY,
 	ETHTOOL_A_MODULE_POWER_MODE,
+	ETHTOOL_A_MODULE_LOOPBACK_CAPABILITIES,
+	ETHTOOL_A_MODULE_LOOPBACK_ENABLED,
 
 	__ETHTOOL_A_MODULE_CNT,
 	ETHTOOL_A_MODULE_MAX = (__ETHTOOL_A_MODULE_CNT - 1)
-- 
2.53.0