[PATCH v2 0/7] slimbus: qcom-ngd-ctrl: Fix some race conditions and deadlocks

[Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>]

When the qcom-ngd-ctrl driver is probed after the ADSP remoteproc, the
SSR notifier will fire immediately, which results in
qcom_slim_ngd_ssr_pdr_notify() attempting to schedule_work() on an
unitialized work_struct.

The concrete result of this is that my db845c/RB3 now fails to boot 100%
of the time.

In reviewing the problematic code, a few other problems where
discovered, such that platform_driver_unregister() is used to unregister
the child device.

Lastly, with the db845c booting, it was determined that attempting to
stop the ADSP remoteproc causes the slimbus driver to deadlock.

Note that while this solves the problems described above, and unblock
boot as well as restart of the remoteproc, this stack needs more love.

Upon tearing down the slimbus controller (when the ADSP goes down), the
slimbus devices attempts to access their slimbus devices - which is
prevented by the controller being runtime suspended. This results in a
wall of errors in the log, about failing transactions.

Signed-off-by: Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>
---
Changes in v2:
- Left devm_request_irq() in its old place, added IRQF_NO_AUTOEN
  instead.
- Changed order of platform_driver_register, to avoid the possible issue
  that controller probe completes without the NGD being present.
- Cleaned up commit message of the "slimbus: qcom-ngd-ctrl: Correct PDR
  and SSR cleanup ownership" patch.
- Link to v1: https://lore.kernel.org/r/20260309-slim-ngd-dev-v1-0-5843e3ed62a3@oss.qualcomm.com

---
Bjorn Andersson (7):
      slimbus: qcom-ngd-ctrl: Fix up platform_driver registration
      slimbus: qcom-ngd-ctrl: Fix probe error path ordering
      slimbus: qcom-ngd-ctrl: Correct PDR and SSR cleanup ownership
      slimbus: qcom-ngd-ctrl: Register callbacks after creating the ngd
      slimbus: qcom-ngd-ctrl: Initialize controller resources in controller
      slimbus: qcom-ngd-ctrl: Balance pm_runtime enablement for NGD
      slimbus: qcom-ngd-ctrl: Avoid ABBA on tx_lock/ctrl->lock

 drivers/slimbus/qcom-ngd-ctrl.c | 120 +++++++++++++++++++++++++---------------
 1 file changed, 76 insertions(+), 44 deletions(-)
---
base-commit: 36ece9697e89016181e5ae87510e40fb31d86f2b
change-id: 20260211-slim-ngd-dev-74166f29f035

Best regards,
-- 
Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>