[PATCH v2 0/2] soc: qcom: rpmh-rsc: Updates for RPMh read requests

[Maulik Shah <maulik.shah@oss.qualcomm.com>]

This series carries two RPMh read request updates.

RSC v4.5 and newer expect read commands to use a 4-byte message payload,
while write commands continue to use 8 bytes. Update the message length
used for read requests on those controllers.

Some platforms either do not support RPMh read requests or AOSS does not
respond to them. Issuing a read there can occupy an ACTIVE TCS indefinitely
and block subsequent write requests. Skip read commands on sm8150 and
sc8180x [1] returning a zero resource level so callers avoid error handling
for an unsupported read path.

Patch 1 has no dependency. A Fixes tag is not required because existing
upstream SoCs use RSC versions older than v4.5. Patch 1 can be applied as
preparation for Hawi SoC support.

Patch 2 carries a Fixes tag. I do not have sm8150 or sc8180x hardware to
verify patch 2. If there are reports like [1] of read requests not working
on past SoCs, the list can be expanded in rpmh_rsc_no_rpmh_read().

[1] https://lore.kernel.org/linux-arm-msm/0a73bc50-71f4-43f8-9d95-14a763d63c61@oss.qualcomm.com/

Signed-off-by: Maulik Shah <maulik.shah@oss.qualcomm.com>
---
Changes in v2:
- Define CMD_MSGID_LEN as a field and use FIELD_PREP() for lengths.
- Keep the read length selection explicit for RSC v4.5 and newer.
- Keep Tested-by for patch-1.
- No changes to patch-2.
- Link to v1: https://patch.msgid.link/20260910-rsc_read-v1-0-c9b7fa3cdde2@oss.qualcomm.com

To: Bjorn Andersson <andersson@kernel.org>
To: Konrad Dybcio <konradybcio@kernel.org>
To: Maulik Shah <maulik.shah@oss.qualcomm.com>
To: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
To: Mark Brown <broonie@kernel.org>
To: Kamal Wadhwa <kamal.wadhwa@oss.qualcomm.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

---
Maulik Shah (2):
      soc: qcom: rpmh-rsc: Update CMD_MSGID_LEN to 4 bytes for read request
      soc: qcom: rpmh-rsc: Skip read requests on unsupported platforms

 drivers/soc/qcom/rpmh-internal.h |  2 ++
 drivers/soc/qcom/rpmh-rsc.c      | 21 ++++++++++++++++++---
 drivers/soc/qcom/rpmh.c          |  6 ++++++
 3 files changed, 26 insertions(+), 3 deletions(-)
---
base-commit: c68a982815dcce5464e3bf2a31ac94f5146c04ca
change-id: 20260910-rsc_read-27d689e37cb5

Best regards,
--  
Maulik Shah <maulik.shah@oss.qualcomm.com>