[PATCH V5 - RESEND 0/3] coresight: etm: Make cycle count threshold user configurable

[Anshuman Khandual]

This series makes ETM TRCCCCTRL based 'cc_threshold' user configurable via
the perf event attribute. But first, this implements an errata work around
affecting ETM TRCIDR3.CCITMIN value on certain cpus, overriding the field.

This series applies on coresight/for-next/queue.

Cc: Catalin Marinas <catalin.marinas at arm.com> 
Cc: Will Deacon <will at kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose at arm.com> 
Cc: Mike Leach <mike.leach at linaro.org>
Cc: James Clark <james.clark at arm.com>
Cc: Leo Yan <leo.yan at linaro.org>
Cc: Jonathan Corbet <corbet at lwn.net>
Cc: linux-doc at vger.kernel.org
Cc: coresight at lists.linaro.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org

Changes in V5:

https://lore.kernel.org/all/20230821045216.641499-1-anshuman.khandual@arm.com/

- Replaced 'where as' with single word 'whereas'
- Reworked 'cc_threshold' fallback to ETM_CYC_THRESHOLD_DEFAULT

Changes in V4:

https://lore.kernel.org/all/20230818112051.594986-1-anshuman.khandual@arm.com/

- Fixed a typo s/rangess/ranges,
- Renamed etm4_work_around_wrong_ccitmin() as etm4_core_reads_wrong_ccitmin()
- Moved drvdata->ccitmin value check for 256 inside etm4_core_reads_wrong_ccitmin()
- Moved the comment inside etm4_core_reads_wrong_ccitmin()

Changes in V3:

https://lore.kernel.org/all/20230811034600.944386-1-anshuman.khandual@arm.com/

- Added errata work around affecting TRCIDR3.CCITMIN
- Split the document update into a separate patch

Changes in V2:

https://lore.kernel.org/all/20230808074533.380537-1-anshuman.khandual@arm.com/

- s/treshhold/threshold

Changes in V1:

https://lore.kernel.org/all/20230804044720.1478900-1-anshuman.khandual@arm.com/

Anshuman Khandual (3):
  coresight: etm: Override TRCIDR3.CCITMIN on errata affected cpus
  coresight: etm: Make cycle count threshold user configurable
  Documentation: coresight: Add cc_threshold tunable

 Documentation/arch/arm64/silicon-errata.rst   | 10 +++++
 Documentation/trace/coresight/coresight.rst   |  4 ++
 .../hwtracing/coresight/coresight-etm-perf.c  |  2 +
 .../coresight/coresight-etm4x-core.c          | 45 ++++++++++++++++++-
 4 files changed, 59 insertions(+), 2 deletions(-)

-- 
2.25.1