[PATCH v4 0/4] PM: QoS/pmdomains: support resume latencies for system-wide PM

Currently QoS resume latencies are only considered for runtime PM
transitions of pmdomains, which remains the default.

In order to also support QoS resume latencies during system-wide PM,
add a new flag to indicate a resume latency should be used for
system-wide PM *in addition to* runtime PM.

If a user requires a different latency value for system-wide PM
compared to runtime PM, then the runtime PM value can be set for
normal operations, and the system-wide value (and flag) can be set by
during suspend (for example in a drivers ->prepare() hook) and the
runtime PM value can be restored after resume (for example, in a
driver's ->complete() hook.)

To: Rafael J. Wysocki <[email protected]>
To: Ulf Hansson <[email protected]>
To: [email protected]

Signed-off-by: Kevin Hilman (TI) <[email protected]>
---
Changes in v4:
- added corresponding WRITE_ONCE() to match READ_ONCE()
- rebase to v7.2
- Link to v3: https://patch.msgid.link/20260611-topic-lpm-pmdomain-device-constraints-v3-0-75d69438518b@baylibre.com

Changes in v3:
- rebased to v7.0
- fix PREEMPT_RT: add new helper for lockless read of flags for atomic contexts 
- update kerneldoc for genpd_for_each_child() as requested by Ulf
- Link to v2: https://patch.msgid.link/20260205-topic-lpm-pmdomain-device-constraints-v2-0-61f7be7d35ac@baylibre.com

Changes in v2:
- drop the userspace interface
- add genpd helper to iterate over all devices in domain and child domains
- new flag means latency applies to runtime PM *and* system-wide PM
- Link to v1: https://patch.msgid.link/20260120-topic-lpm-pmdomain-device-constraints-v1-0-108fc4cfafce@baylibre.com

---
Kevin Hilman (TI) (4):
      PM / QoS: add flag to indicate latency applies system-wide
      PM / QoS: add lockless read for flags
      pmdomain: core: add genpd_for_each_child() helper
      pmdomain: add support system-wide resume latency constraints

 drivers/pmdomain/core.c     | 45 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/pmdomain/core.h     | 17 +++++++++++++++++
 drivers/pmdomain/governor.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pm_qos.h      |  9 +++++++++
 kernel/power/qos.c          |  4 ++--
 5 files changed, 129 insertions(+), 2 deletions(-)
---
base-commit: 237a1c39e8dfd3e1c6f1f023eea37a48ec04cc63
change-id: 20260120-topic-lpm-pmdomain-device-constraints-e5e78ce48502

Best regards,
--  
Kevin Hilman (TI) <[email protected]>