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[v7,0/3] SCM: Support latest version of waitq-aware firmware

Message ID 20250523-multi_waitq_scm-v7-0-5b51b60ed396@oss.qualcomm.com
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Series SCM: Support latest version of waitq-aware firmware | expand

Message

Unnathi Chalicheemala May 23, 2025, 7:07 p.m. UTC 
This series adds support for the latest improvements made in SCM
firmware that allow for multiple wait-queues in firmware.

To support multi VM synchronization when VMs make SMC calls on same CPU,
waitqueue mechanism is added in firmware which runs at EL2 & EL3 exception
levels.

P.S. While at Qualcomm, Guru Das Srinagesh authored the initial version of
these patches.
Thanks Guru!

---
Changes in v7:
- Assume failing scm call to mean WAITQ_GET_INFO is not supported on target
  as qcom_scm_is_call_available() is handled in Qualcomm firmware's TZ (EL3),
  which doesn’t implement WAITQ_GET_INFO, and therefore always returns 0.
- Link to v6: https://lore.kernel.org/r/20250425-multi_waitq_scm-v6-0-cba8ca5a6d03@oss.qualcomm.com

Changes in v6:
- Added R-b tag from Bartosz for first patch.
- Check if QCOM_SCM_WAITQ_GET_INFO is available before making scm call,
instead of assuming failing scm call to mean WAITQ_GET_INFO is not
supported on target.
- Add a new patch to check for waitq idle state in wait_for_wq_completion(). 
- Link to v5: https://lore.kernel.org/all/20250227-multi_waitq_scm-v5-0-16984ea97edf@oss.qualcomm.com/ 

Changes in v5:
- Use GIC_SPI and GIC_ESPI macros from dt-bindings instead of redefining
- Modified qcom_scm_query_waitq_count to take struct qcom_scm as
argument; scm is anyway stored to global struct __scm after
smp_store_and_release().
- Tested on SM8650 which has multi-waitq support and SM8550, which
doesn't. No error logs are seen.
-Link to v4: https://lore.kernel.org/all/cover.1730742637.git.quic_uchalich@quicinc.com/

Changes in v4:
- Moving back to redefining GIC_IRQ_TYPE_SPI and GIC_IRQ_TYPE_ESPI macros
in qcom_scm as seeing compilation issues in linux/irq.h when including
arm-gic header. Will send a fixes patch and move to dt-bindings in next patchset.
- Fixed a few compilation errors.
- Link to v3: https://lore.kernel.org/all/cover.1730735881.git.quic_uchalich@quicinc.com/

Changes in v3:
- Use GIC_SPI and GIC_ESPI macros from dt-bindings instead of redefining
- Prettified qcom_scm_fill_irq_fwspec_params()
- Moved waitq initialization before smp_store_release()
- There is no Gunyah hypercall API that can be used to fetch IRQ information hence
introducing new SCM call.
- Link to v2: https://lore.kernel.org/all/cover.1724968351.git.quic_uchalich@quicinc.com/

Changes in v2:
- Dropped "Initialize waitq before setting global __scm" as it was merged here:
https://lore.kernel.org/r/1711034642-22860-4-git-send-email-quic_mojha@quicinc.com
- Decoupled "Remove QCOM_SMC_WAITQ_FLAG_WAKE_ALL" from series
- Converted xarray to a statically sized array
- Initialize waitq array in probe function
- Remove reinit of waitq completion struct in scm_get_completion()
- Introduced new APIs to get no. of waitqueue contexts and waitqueue IRQ no.
directly from firmware.
- Link to v1: https://lore.kernel.org/all/20240228-multi_waitq-v1-0-ccb096419af0@quicinc.com/

---
Unnathi Chalicheemala (3):
      firmware: qcom_scm: Add API to get waitqueue IRQ info
      firmware: qcom_scm: Support multiple waitq contexts
      firmware: qcom_scm: Check for waitq state in wait_for_wq_completion()

 drivers/firmware/qcom/qcom_scm.c | 127 +++++++++++++++++++++++++++++++++------
 drivers/firmware/qcom/qcom_scm.h |   1 +
 2 files changed, 109 insertions(+), 19 deletions(-)
---
base-commit: e85dea591fbf900330c796579314bfb7cc399d31
change-id: 20250227-multi_waitq_scm-5bf05480b7b1

Best regards,