[PATCH v2 0/3] media: qcom: Skip SCM secure memory protection with OP-TEE PAS backend

[Sumit Garg]

The Qualcomm peripheral authentication service (PAS) can be serviced by
either the SCM (TrustZone) backend or, on OP-TEE based platforms, by the
OP-TEE backend. qcom_scm_mem_protect_video_var() is only implemented by
the SCM backend; with OP-TEE the TEE itself owns secure memory
protection and does not service this call. Issuing it unconditionally on
an OP-TEE backend fails firmware bring-up for the venus and iris video
codecs.

Patch 1 adds an optional PAS op along with a generic
qcom_pas_mem_protect_video_var() wrapper. The SCM backend maps it to the
existing SCM call, while backends that leave it unset get a no-op.
Patch 2 switches the venus and iris drivers to the new API, so that they
stay agnostic of the active PAS backend, and drops their Kconfig
dependency on QCOM_SCM. Patch 3 folds the SCM call into the SCM PAS
backend and drops its export.

No functional change is intended for the SCM backend.

Changes in v2:
- Dropped the qcom_pas_get_backend() helper and the backend name
  matching in the video drivers, as suggested by Konrad and Vikash.
- Stubbed the video memory protection call via the generic PAS layer
  instead, with the SCM backend reusing the existing abstraction.
- Dropped the QCOM_SCM Kconfig selection from the venus and iris drivers.
- Added patch 3 to drop the export of qcom_scm_mem_protect_video_var().
- Link to v1: https://lore.kernel.org/all/20260911-video-optee-pas-v1-v1-0-7bbddaaac5ba@xxxxxxxxxx/

---
Sumit Garg (3):
      firmware: qcom: pas: Add optional video memory protection op
      media: qcom: Use PAS API for video memory protection
      firmware: qcom: scm: Drop export of qcom_scm_mem_protect_video_var()

 drivers/firmware/qcom/qcom_pas.c                 | 27 +++++++++++++
 drivers/firmware/qcom/qcom_pas.h                 |  5 +++
 drivers/firmware/qcom/qcom_scm.c                 | 48 ++++++++++++------------
 drivers/media/platform/qcom/iris/Kconfig         |  1 -
 drivers/media/platform/qcom/iris/iris_firmware.c |  5 +--
 drivers/media/platform/qcom/venus/Kconfig        |  1 -
 drivers/media/platform/qcom/venus/firmware.c     |  3 +-
 include/linux/firmware/qcom/qcom_pas.h           |  2 +
 include/linux/firmware/qcom/qcom_scm.h           |  2 -
 9 files changed, 61 insertions(+), 33 deletions(-)
---
base-commit: 75a4de0d94f62bce938ebcacd8a7a8ed35a0439b
change-id: 20261027-pas-video-65c73f482b20

Best regards,
-- 
Sumit Garg <sumit.garg@xxxxxxxxxxxxxxxx>