Bug 520 - Need a way to disable WB interface in core in case it gets stuck active
Summary: Need a way to disable WB interface in core in case it gets stuck active
Status: CONFIRMED
Alias: None
Product: Libre-SOC's first SoC
Classification: Unclassified
Component: Source Code (show other bugs)
Version: unspecified
Hardware: PC Linux
: Highest major
Deadline: 2020-10-30
Assignee: Luke Kenneth Casson Leighton
URL:
Depends on:
Blocks: 383
  Show dependency treegraph
 
Reported: 2020-10-22 00:06 BST by Cole Poirier
Modified: 2020-10-22 17:02 BST (History)
2 users (show)

See Also:
NLnet milestone: NLNet.2019.10.Wishbone
total budget (EUR) for completion of task and all subtasks: 0
budget (EUR) for this task, excluding subtasks' budget: 0
parent task for budget allocation: 383
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Description Cole Poirier 2020-10-22 00:06:38 BST
a means is needed to be able to disable the wishbone interfaces via JTAG.
Comment 1 Luke Kenneth Casson Leighton 2020-10-22 14:13:51 BST
commit 9e4b927a1ab37f5b17038af05731004a3654f56f (HEAD -> master)
Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date:   Thu Oct 22 14:13:11 2020 +0100

    add means to JTAG interface to enable/disable "stuff"  currently just WB
Comment 2 Luke Kenneth Casson Leighton 2020-10-22 16:50:54 BST
commit 36b156d4df4fb94615b0c7134b191ceaa7f82678 (HEAD -> master)
Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date:   Thu Oct 22 16:50:37 2020 +0100

    add detection and disable of Instruction Wishbone based on JTAG command

commit 7db34597c3888b7aa19afb918aecf5f52fe7b590
Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date:   Thu Oct 22 16:49:11 2020 +0100

    add detection and disable of LoadStore Wishbone based on JTAG command

commit c578a8ef645d55a3bde21a3abf530dd9016687ab
Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date:   Thu Oct 22 16:47:23 2020 +0100

    add JTAG enable/disable of wishbone to TestIssuer
Comment 3 Luke Kenneth Casson Leighton 2020-10-22 16:58:44 BST
TODO: resolve if we care about cross-domain clock synchronisation on the
jtag-controlled wb-en signals
Comment 4 Jacob Lifshay 2020-10-22 17:02:08 BST
I'd imagine we'd reset everything but jtag after disabling wb interfaces, so, probably not, though it wouldn't hurt to have cross-domain synchronization anyway.