[PATCH v6 00/11] CoreSight: Refactor power management for ETMv3/4

[Leo Yan]

This series is extracted from the CoreSight power management fixes and
refactoring [1], focusing on ETMv3/4 power management.

This series has been verified on Juno-r2 platform.

[1] https://lore.kernel.org/linux-arm-kernel/20250915-arm_coresight_power_management_fix-v3-0-ea49e91124ec@arm.com/

---
Changes in v6:
- Added a 'retain_ss_status' flag to indicate if need to restain
  single-shot status (Suzuki).
- Introduced __etm4_disable_hw() without calling
  etm4_cs_{unlock|lock}() pairs, which is convenient for the save
  callback (Suzuki).
- Link to v5: https://lore.kernel.org/r/20251103-arm_coresight_power_management_fix-v5-0-f803c19aa153@arm.com

Changes in v5:
- Added more info for removing redundant DSB in
  etm4_{enable|disable}_trace_unit() (Suzuki/Levi).
- Dropped moving isb() out from etm4_{enable|disable}_trace_unit()
  (Suzuki).
- Reordered patches to move fixes earlier.
- Link to v4: https://lore.kernel.org/r/20251024-arm_coresight_power_management_fix-v4-0-690e69ae6977@arm.com

Changes in v4:
- Added patch 10 for retaining sequencer state in ETMv4 driver (Mike).
- Added Mike's review tags.
- Added James' test tags.
- Link to v3: https://lore.kernel.org/r/20250915-arm_coresight_power_management_fix-v3-0-ea49e91124ec@arm.com

Changes in v3:
- Fixed building failure in ETMv3 driver (kernel test robot).
- Refactoring ETMv3 change for checking CPU ID (Levi).
- Fixed NULL pointer issue during CPU idle (James).
- Fixed lockdep complaint for HARDIRQ-safe and HARDIRA-unsafe (James).
- Fixed acquiring mutex in atomic context (James).
- Rebased on the latest coresight-next branch.
- Link to v2: https://lore.kernel.org/r/20250701-arm_cs_pm_fix_v3-v2-0-23ebb864fcc1@arm.com

Changes in v2:
- Refactored ETMv4 suspend and resume for reusing the normal enabling
  and disabling flows (James).
- Used a per-CPU structure to maintain path pointers (James).
- Supported helpers in CPU PM flows (James).
- Fixed the SMP-safe access to device mode.
- Fixed the context synchronization in ETMv4x driver.
- Link to v1: https://lore.kernel.org/linux-arm-kernel/20250516160742.1200904-1-leo.yan@arm.com/

Signed-off-by: Leo Yan <leo.yan at arm.com>

---
Leo Yan (11):
      coresight: Change device mode to atomic type
      coresight: etm4x: Always set tracer's device mode on target CPU
      coresight: etm3x: Always set tracer's device mode on target CPU
      coresight: etm4x: Correct polling IDLE bit
      coresight: etm4x: Add context synchronization before enabling trace
      coresight: etm4x: Properly control filter in CPU idle with FEAT_TRF
      coresight: etm4x: Remove the redundant DSB
      coresight: etm4x: Remove the state_needs_restore flag
      coresight: etm4x: Add flag to retain single-shot status
      coresight: etm4x: Retain sequencer state
      coresight: etm4x: Reuse normal enable and disable logic in CPU idle

 drivers/hwtracing/coresight/coresight-etm3x-core.c |  59 ++--
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 358 +++++++--------------
 drivers/hwtracing/coresight/coresight-etm4x.h      |  64 +---
 include/linux/coresight.h                          |  25 +-
 4 files changed, 172 insertions(+), 334 deletions(-)
---
base-commit: b139702a889692ec30702534ebb1ae2b11ed1cbf
change-id: 20250909-arm_coresight_power_management_fix-139873f942e8

Best regards,
-- 
Leo Yan <leo.yan at arm.com>