[PATCH v3 0/3] soc: qcom: qcom_stats: Add DDR stats

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

This series adds support to read various DDR low power mode and frequency
stats. This was added in past with series [1] but reverted with [4] due
to some SoCs boot up failures. This series is more aligned to downstream
implementation and fixes the issues mentioned in [4].

The series [1] tried to add three feature support

A. Reading DDR Frequency and low power stats from MSG RAM
   (targets where DDR stats are readily available in MSG RAM to read)

B. Trigger QMP to ask AOP to populate DDR Frequency and low power stats
   (targets where DDR stats are available but duration field syncing
   requires QMP message to be sent to AOP)

C. Trigger QMP to ask AOP to populate DDR vote table information
   (To read different DRV / Direct Resource Voter, CPUSS, DSPs's votes
   for DDR frequency)

Current series do not include reading the DDR vote table information (C)
part from [1] which is to be separately sent potentially including reading
other resources votes like Cx Rail level vote information. These vote
tables details are not strictly related to DDR Frequency and low power
stats (A) and (B) this series is adding.

This series updates respective SoC devicetree with QMP handle (where DDR
stats syncing is required) and it is backward compatible with older
devicetree as without the QMP handle present, ddr stats can be still be
read (duration field will be read as 0).

Note that [1] was only partially reverted and hence device binding update
for QMP handle [2] is already present along with the fix to have
dependency on AOSS QMP driver in Kconfig [3].

[1] https://lore.kernel.org/all/20231130-topic-ddr_sleep_stats-v1-0-5981c2e764b6@linaro.org/
[2] https://lore.kernel.org/all/20231130-topic-ddr_sleep_stats-v1-2-5981c2e764b6@linaro.org/
[3] https://lore.kernel.org/lkml/20231205-qcom_stats-aoss_qmp-dependency-v1-1-8dabe1b5c32a@quicinc.com/T/
[4] https://lore.kernel.org/all/20231214-topic-undo_ddr_stats-v1-1-1fe32c258e56@linaro.org/

Signed-off-by: Maulik Shah <maulik.shah@oss.qualcomm.com>
---
Changes in v3:
- Use correct format specifiers
- Handle qmp_get() failure cases
- Link to v2: https://lore.kernel.org/r/20250521-ddr_stats_-v2-0-2c54ea4fc071@oss.qualcomm.com

Changes in v2:
- Mention count in decimal instead of hex
- Update read failure cases to return error code instead of success
- Fix typo in comment
- Link to v1: https://lore.kernel.org/r/20250429-ddr_stats_-v1-0-4fc818aab7bb@oss.qualcomm.com

---
Maulik Shah (3):
      soc: qcom: qcom_stats: Add support to read DDR statistic
      soc: qcom: qcom_stats: Add QMP support for syncing ddr stats
      arm64: dts: qcom: Add QMP handle for qcom_stats

 arch/arm64/boot/dts/qcom/sm8450.dtsi |   1 +
 arch/arm64/boot/dts/qcom/sm8550.dtsi |   1 +
 arch/arm64/boot/dts/qcom/sm8650.dtsi |   1 +
 arch/arm64/boot/dts/qcom/sm8750.dtsi |   1 +
 drivers/soc/qcom/qcom_stats.c        | 131 +++++++++++++++++++++++++++++++++++
 5 files changed, 135 insertions(+)
---
base-commit: 393d0c54cae31317deaa9043320c5fd9454deabc
change-id: 20250426-ddr_stats_-391505b3da6a

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