)]}'
{"/PATCHSET_LEVEL":[{"author":{"_account_id":1001667,"name":"Jan Matyas","email":"jan.matyas@codasip.com","username":"JanMatCodasip"},"change_message_id":"927a5015dcb8014e1bc85c4c98d6545b0465e041","unresolved":true,"context_lines":[],"source_content_type":"","patch_set":1,"id":"0663cb35_db49ae59","updated":"2024-10-16 06:13:37.000000000","message":"So far I have managed to only take a very quick look at the changes.\n\nI have two early questions, would you have a moment to answer them?\n\n- 1) What are the use cases for these multi-TAP scans?\n- 2) Are any changes needed also in target-dependent code? Do any targets assume that no more than a single TAP can be in non-bypass state?","commit_id":"559b2a6991b060db2d058296e74cf38f866cea89"},{"author":{"_account_id":1002047,"name":"Evgeniy Naydanov","email":"eugnay@gmail.com","username":"en-sc"},"change_message_id":"b14b3035d2ed7c9061b2725b7e538d05b8aeeecb","unresolved":true,"context_lines":[],"source_content_type":"","patch_set":1,"id":"ed6b2788_1ba708f8","in_reply_to":"0663cb35_db49ae59","updated":"2024-10-16 09:46:12.000000000","message":"\u003e What are the use cases for these multi-TAP scans?\n\nThis patch only extends the interface without introducing any uses of the new functionality. You can see the [next patch in the chain](https://review.openocd.org/c/openocd/+/8505/) for an example. That patch extends OpenOCD TCL interface by introducing a new command: `jtag execute ...`. This command allows to execute a multi-TAP scan (among other things).\n\n\u003e Are any changes needed also in target-dependent code? Do any targets assume that no more than a single TAP can be in non-bypass state?\n\nThat is a valid concern. This patch does not require any changes in target-dependent code since the patch only extends library interface without chaning user interface. However, the second patch in the chain(`jtag execute`) does require some changes to target-dependent code (e.g. https://github.com/riscv-collab/riscv-openocd/pull/1146).","commit_id":"559b2a6991b060db2d058296e74cf38f866cea89"},{"author":{"_account_id":1001667,"name":"Jan Matyas","email":"jan.matyas@codasip.com","username":"JanMatCodasip"},"change_message_id":"8aeeb404775561ca12241aa3a8c4e2f9f44376c4","unresolved":false,"context_lines":[],"source_content_type":"","patch_set":1,"id":"0c47679e_06c0af62","in_reply_to":"3b3b0f43_597611f2","updated":"2024-10-17 07:06:59.000000000","message":"Ok, understood. Thanks for explanation.","commit_id":"559b2a6991b060db2d058296e74cf38f866cea89"},{"author":{"_account_id":1002047,"name":"Evgeniy Naydanov","email":"eugnay@gmail.com","username":"en-sc"},"change_message_id":"b0d4300ddb48dfb396653bc7f194f410d93f85a6","unresolved":true,"context_lines":[],"source_content_type":"","patch_set":1,"id":"3b3b0f43_597611f2","in_reply_to":"c6b292b6_b71acfda","updated":"2024-10-16 14:47:52.000000000","message":"\u003e What are the expected use cases?\n\nMulti-TAP scan can be used to achieve near-simultaneous transition of multiple resources to a desired state (e.g. resume multiple harts connected to different TAPs simultaneously).","commit_id":"559b2a6991b060db2d058296e74cf38f866cea89"},{"author":{"_account_id":1001667,"name":"Jan Matyas","email":"jan.matyas@codasip.com","username":"JanMatCodasip"},"change_message_id":"d41b15898bf24ea814acad23a1f4fb5da7fd3adb","unresolved":true,"context_lines":[],"source_content_type":"","patch_set":1,"id":"c6b292b6_b71acfda","in_reply_to":"ed6b2788_1ba708f8","updated":"2024-10-16 12:08:37.000000000","message":"\u003e me: What are the use cases for these multi-TAP scans?\n\n\u003e Evgeniy N.: This patch only extends the interface (...) That [next] patch extends OpenOCD TCL interface by introducing a new command (...)\n\nI mean, once the full feature is in place (including the `jtag execute ...` command), what will the users use it for? What are the expected use cases?","commit_id":"559b2a6991b060db2d058296e74cf38f866cea89"},{"author":{"_account_id":1002047,"name":"Evgeniy Naydanov","email":"eugnay@gmail.com","username":"en-sc"},"change_message_id":"92866bc5f5db65cf187db1ad387a6781f66477ad","unresolved":false,"context_lines":[],"source_content_type":"","patch_set":2,"id":"f08e588b_a9ce3586","updated":"2024-12-20 10:11:35.000000000","message":"Sorry for pinging you all -- I\u0027m not really sure who is the right person to ask for a review here.\n\nPlease take a look at this patch chain when you have the time. Patches return the ability to perform JTAG scans with multiple TAPs active (not in bypass). On some designs this allows to perform an action (e.g. resume) near simultaneously on different cores.\n\nFor now, only TCL interface for the new feature is implemented (the second patch in the chain) in the form of `jtag execute` command. The command also allows to pack multiple scans into a single JTAG queue with the hope of running them with a single USB transaction.","commit_id":"8c37d6fc20fe29766a3efd2f8811d74d7cb3906d"},{"author":{"_account_id":1000853,"name":"zapb","display_name":"Marc Schink","email":"dev@zapb.de","username":"zapb"},"change_message_id":"96b5da8fad254e571b732b09b1644bbdaf301221","unresolved":false,"context_lines":[],"source_content_type":"","patch_set":3,"id":"8fd2a397_6b485b94","updated":"2025-02-26 20:07:23.000000000","message":"@Evgeniy: I would like to test this patch, can you recommend a hardware / setup for testing? I will do some regression testing with existing targets these days.","commit_id":"065a3a2b1fa801781aec3c70b3c28aeccd83caed"},{"author":{"_account_id":1002047,"name":"Evgeniy Naydanov","email":"eugnay@gmail.com","username":"en-sc"},"change_message_id":"8dc98243cc9621a6cf27a7954209076255fe9499","unresolved":false,"context_lines":[],"source_content_type":"","patch_set":3,"id":"a71a57b9_473fe316","in_reply_to":"8fd2a397_6b485b94","updated":"2025-02-28 12:20:39.000000000","message":"Thanks!\n\nYou can use `rbb_daisychain.py` [1] to chain multiple Spike simulators into one JTAG chain (similar to [2]).\n\nAFAIU, you can test this on any setup, chaining TDO to TDI of the next device, though I didn\u0027t try this.\n\nPlease note that to send a multi-TAP scan you will also need the next patch in the chain [2] -- this commit only extends the interface without introducing any new uses of the interface.\n\n[1] https://github.com/riscv-software-src/riscv-tests/blob/master/debug/rbb_daisychain.py\n[2] https://review.openocd.org/c/openocd/+/8070/comments/8c54e2b2_4d41efee\n[3] https://review.openocd.org/c/openocd/+/8505/","commit_id":"065a3a2b1fa801781aec3c70b3c28aeccd83caed"}]}