[RFC,0/8] drm/msm: adreno: add support for DDR bandwidth scaling via GMU

Message

Neil Armstrong Nov. 13, 2024, 3:48 p.m. UTC

The Adreno GMU Management Unit (GMU) can also vote for DDR Bandwidth
along the Frequency and Power Domain level, but by default we leave the
OPP core scale the interconnect ddr path.

While scaling the interconnect path was sufficient, newer GPUs
like the A750 requires specific vote parameters and bandwidth to
achieve full functionnality.

In order to get the vote values to be used by the GPU Management
Unit (GMU), we need to parse all the possible OPP Bandwidths and
create a vote value to be send to the appropriate Bus Control
Modules (BCMs) declared in the GPU info struct.
The added dev_pm_opp_get_bandwidth() is used in this case.

The vote array will then be used to dynamically generate the GMU
bw_table sent during the GMU power-up.

Those entries will then be used by passing the appropriate
bandwidth level when voting for a GPU frequency.

This will make sure all resources are equally voted for a
same OPP, whatever decision is done by the GMU, it will
ensure all resources votes are synchronized.

Tested on SM8650 and SM8550 platforms.

Any feedback is welcome.

Signed-off-by: Neil Armstrong <[e-mail]>
---
Neil Armstrong (8):
      opp: core: implement dev_pm_opp_get_bandwidth
      drm/msm: adreno: add GMU_BW_VOTE quirk
      drm/msm: adreno: add plumbing to generate bandwidth vote table for GMU
      drm/msm: adreno: dynamically generate GMU bw table
      drm/msm: adreno: find bandwidth index of OPP and set it along freq index
      drm/msm: adreno: enable GMU bandwidth for A740 and A750
      arm64: qcom: dts: sm8550: add interconnect and opp-peak-kBps for GPU
      arm64: qcom: dts: sm8650: add interconnect and opp-peak-kBps for GPU

 arch/arm64/boot/dts/qcom/sm8550.dtsi      |  11 ++
 arch/arm64/boot/dts/qcom/sm8650.dtsi      |  14 +++
 drivers/gpu/drm/msm/adreno/a6xx_catalog.c |  26 ++++-
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c     | 180 +++++++++++++++++++++++++++++-
 drivers/gpu/drm/msm/adreno/a6xx_gmu.h     |  14 ++-
 drivers/gpu/drm/msm/adreno/a6xx_gpu.h     |   1 +
 drivers/gpu/drm/msm/adreno/a6xx_hfi.c     |  54 ++++++---
 drivers/gpu/drm/msm/adreno/adreno_gpu.h   |   1 +
 drivers/opp/core.c                        |  25 +++++
 include/linux/pm_opp.h                    |   7 ++
 10 files changed, 314 insertions(+), 19 deletions(-)
---
base-commit: 86313a9cd152330c634b25d826a281c6a002eb77
change-id: 20241113-topic-sm8x50-gpu-bw-vote-f5e022fe7a47

Best regards,