[v4,0/6] Describe CoreSight topology using sysfs links.

Message

Mike Leach Feb. 11, 2020, 10:58 a.m. UTC

The connections between CoreSight sources, links and sinks is not obvious
without documentation or access to the device tree / ACPI definitions for
the platform.

This patchset provides sysfs links to enable the user to follow the trace
patch from source to sink.

Components in the trace path are updated to have a connections sysfs
group, which collates all the links for that component.

The CTI components which exist aside from the main trace patch, also
have an added connections directory showing connections to other
CoreSight devices.

This patchset applies on top of the recent CTI v9 patchset [1].

Adaptation of an original patchset [2] from Suzuki, reusing 2 patches
unchanged with update to 3rd adapt to the new common code for trace
path and CTI component links & add a default connections group.

Tested on Juno r1, DB410c; kernel 5.6-rc1

[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2020-February/709923.html
[2] https://lists.linaro.org/pipermail/coresight/2019-May/002803.html

Changes since v3:
1) Rebased onto 5.6-rc1 kernel with CTI set[1].

Changes since v2:
1) Fixed issues with signature ordering noted by Suzuki.
2) Alterations to main CTI set[1] to overcome issue noted by Matthieu.

Changes since v1:
1) Code from original v4 CTI set moved here so that all connections related
code in this set.
2) Connections directory mandatory for all CoreSight components and
generated as part of the registration process.

Mike Leach (3):
  coresight: Add generic sysfs link creation functions.
  coresight: cti: Add in sysfs links to other coresight devices.
  coresight: docs: Add information about the topology representations.

Suzuki K Poulose (3):
  coresight: Pass coresight_device for coresight_release_platform_data
  coresight: add return value for fixup connections
  coresight: Expose device connections via sysfs

 .../trace/coresight/coresight-ect.rst         |   5 +-
 Documentation/trace/coresight/coresight.rst   |  85 ++++++++
 drivers/hwtracing/coresight/Makefile          |   3 +-
 drivers/hwtracing/coresight/coresight-cti.c   |  41 +++-
 .../hwtracing/coresight/coresight-platform.c  |   2 +-
 drivers/hwtracing/coresight/coresight-priv.h  |  12 +-
 drivers/hwtracing/coresight/coresight-sysfs.c | 204 ++++++++++++++++++
 drivers/hwtracing/coresight/coresight.c       |  75 ++++---
 include/linux/coresight.h                     |  22 ++
 9 files changed, 420 insertions(+), 29 deletions(-)
 create mode 100644 drivers/hwtracing/coresight/coresight-sysfs.c