[PATCH v2 0/7] Introduce the Interconnect Subsystem

[Neil Armstrong]

Let's introduce the Interconnect subsystem based on the Linux framework
which is used to vote for bandwidth across multiple SoC busses.

Each bus endpoints are materialised as "nodes" which are linked together,
and the DT will specify a pair of nodes to enable and set a bandwidth
on the route betweeen those endpoints.

The hardware resources that provide those nodes and provides the way
to vote for the bandwidth are called "providers".

The Interconnect uclass code is heavily based on the Linux one, with
some small differences:
- nodes are allocated as udevices instead of Linux idr_alloc()
- tag management is minimal, only normal xlate is supported
- dynamic IDs is not implemented
- getting nodes states at probe is not implemented
- providers are probed on demand while the nodes links are traversed

DM Testsuite is provided, testing all the API and nodes lifetime.

Qcom implementation depends on:
- https://lore.kernel.org/all/20250711143851.1490617-2-aswin.murugan@oss.qualcomm.com/

Signed-off-by: Neil Armstrong <neil.armstrong at linaro.org>
---
Changes in v2:
- Simplified nodes linking, looking for nodes at traversal instead of complexe debice reparent
- Populates nodes at bind time, only probinf nodes and providers when a path if found
- With proper refcounting the node lifetime is safe
- DM test is added, testing with a small graph that calculations are good
- Fixed plenty of typo and errors, and dropped useless code
- Dropped RFC since DM test is available, and code works as expected
- Link to v1: https://lore.kernel.org/r/20251003-topic-interconnect-next-v1-0-955eef068b6e@linaro.org

---
Neil Armstrong (7):
      Introduce the Interconnect Subsystem
      interconnect: add DM test suite
      MAINTAINERS: add myself as Maintainer of Interconnect
      interconnect: add support for the Qualcomm RPMh helpers
      interconnect: add support for the SM8650 SoC
      ufs: qcom: vote for interconnect bandwidth on probe
      qcom_defconfig: enable interconnect for SM8650

 MAINTAINERS                                      |   10 +
 arch/sandbox/dts/test.dts                        |   36 +
 arch/sandbox/include/asm/interconnect.h          |   19 +
 configs/qcom_defconfig                           |    3 +
 configs/sandbox64_defconfig                      |    2 +
 configs/sandbox_defconfig                        |    2 +
 drivers/Kconfig                                  |    2 +
 drivers/Makefile                                 |    1 +
 drivers/interconnect/Kconfig                     |   22 +
 drivers/interconnect/Makefile                    |    8 +
 drivers/interconnect/interconnect-uclass.c       |  548 +++++++
 drivers/interconnect/qcom/Kconfig                |   12 +
 drivers/interconnect/qcom/Makefile               |    7 +
 drivers/interconnect/qcom/bcm-voter.c            |  340 +++++
 drivers/interconnect/qcom/bcm-voter.h            |   19 +
 drivers/interconnect/qcom/icc-rpmh.c             |  222 +++
 drivers/interconnect/qcom/icc-rpmh.h             |  129 ++
 drivers/interconnect/qcom/sm8650.c               | 1664 ++++++++++++++++++++++
 drivers/interconnect/qcom/sm8650.h               |  144 ++
 drivers/interconnect/sandbox-interconnect-test.c |   89 ++
 drivers/interconnect/sandbox-interconnect.c      |  338 +++++
 drivers/ufs/ufs-qcom.c                           |   13 +
 include/dm/uclass-id.h                           |    2 +
 include/interconnect-uclass.h                    |   74 +
 include/interconnect.h                           |   81 ++
 test/dm/Makefile                                 |    1 +
 test/dm/interconnect.c                           |  148 ++
 27 files changed, 3936 insertions(+)
---
base-commit: b8cea886d50e6c09985256e546904d640f600e4d
change-id: 20251003-topic-interconnect-next-4ed75aecc01c

Best regards,
-- 
Neil Armstrong <neil.armstrong at linaro.org>