Merge pull request #971 from shyam77git/patch-1

Added feature enablement workflow to enable/disable 400G Interface link bring-up sequence

doc/sfp-cmis/Interface-Link-bring-up-sequence.md

@@ -23,15 +23,17 @@ Deterministic Approach for Interface Link bring-up sequence
   * [Table 2: References](#table-2-references)
 
 # Revision
-| Rev |     Date    |       Author                       | Change Description                |
-|:---:|:-----------:|:----------------------------------:|-----------------------------------|
+| Rev |     Date    |       Author                       | Change Description                  |
+|:---:|:-----------:|:----------------------------------:|-------------------------------------|
 | 0.1 | 08/16/2021  | Shyam Kumar                        | Initial version                       
 | 0.2 | 12/13/2021  | Shyam Kumar,  Jaganathan Anbalagan | Added uses-cases, workflows  
 | 0.3 | 01/19/2022  | Shyam Kumar,  Jaganathan Anbalagan | Addressed review-comments    
 | 0.4 | 01/26/2022  | Shyam Kumar,  Jaganathan Anbalagan | Addressed further review-comments 
 | 0.5 | 01/28/2022  | Shyam Kumar,  Jaganathan Anbalagan | Addressed further review-comments
 | 0.6 | 02/02/2022  | Shyam Kumar                        | Added feature-enablement workflow 
 | 0.7 | 02/02/2022  | Jaganathan Anbalagan               | Added Breakout Handling 
+| 0.8 | 02/16/2022  | Shyam Kumar                        | Updated feature-enablement workflow
+| 0.9 | 04/05/2022  | Shyam Kumar                        | Addressed review comments           |
 
 
 # About this Manual
@@ -149,11 +151,18 @@ Please refer to the  flow/sequence diagrams which covers the following required
 # Feature enablement
   This feature (optics Interface Link bring-up sequence) would be enabled on per platform basis.
   There could be cases where vendor(s)/platform(s) may take time to shift from existing codebase to the model (work-flows) described in this document.
-  In order to avoid any breakage and ensure gradual migration of different platforms/vendors to this model, there would be new field (flag) in xcvrd to enable/disable this feature. 
-  When xcvrd spawns on LC/board, it would invoke platform plugin to check with the platform (hwsku) whether this feature is yet supported on underlying platform (board/LC) or not
+  In order to avoid any breakage and ensure gradual migration of different platforms/vendors to this model, will add this new workflow to enable/disable this feature:
+
+  In order to enable this feature, the platform would set ‘skip_xcvrd_cmis_mgr’ to ‘false’ in their respective pmon_daemon_control.json as part of platform bootstrap. When xcvrd would spawn on that hwsku (LC/board), it would parse ‘skip_xcvrd_cmis_mgr’ and if found 'false', it would launch CMIS task manager. This implies enabling this feature. 
+
+Else, if ‘skip_xcvrd_cmis_mgr’ is set/found 'true' by xcvrd, it would skip launching CMIS task manager and this feature would remain disabled.
+If a platform/vendor does not specify/set ‘skip_xcvrd_cmis_mgr’, xcvrd would exercise the default workflow (i.e. when xcvrd detects QSFP-DD, it would luanch CMIS task manager and initialize the module per CMIS specification). 
+
+Note: This feature flag (skip_xcvrd_cmis_mgr) was added as a flexibility in case vendor/platform intend to disable this feature and not use CMIS task manager. However, techinically, as mentioned in this document, that should not be the case.
 
   Workflow :
-  ![Enabling 'Interface link bring-up sequence' feature(3)](https://user-images.githubusercontent.com/69485234/152266723-050377ce-d4de-4c67-a405-5acc66474d46.png)
+  ![Enabling 'Interface link bring-up sequence' feature(2)](https://user-images.githubusercontent.com/69485234/154403945-654b49d7-e85f-4a7a-bb4d-e60a16b826a7.png)
+
 
 
 # Transceiver Initialization