[v4,0/3] interconnect: Add path tagging support

Message

Georgi Djakov Aug. 13, 2019, 2:53 p.m. UTC

SoCs that have multiple coexisting CPUs and DSPs, may have shared
interconnect buses between them. In such cases, each CPU/DSP may have
different bandwidth needs, depending on whether it is active or sleeping.
This means that we have to keep different bandwidth configurations for
the CPU (active/sleep). In such systems, usually there is a way to
communicate and synchronize this information with some firmware or pass
it to another processor responsible for monitoring and switching the
interconnect configurations based on the state of each CPU/DSP.

The above problem can be solved by introducing the path tagging concept,
that allows consumers to optionally attach a tag to each path they use.
This tag is used to differentiate between the aggregated bandwidth values
for each state. The tag is generic and how it's handled is up to the
platform specific interconnect provider drivers.

v4:
- Picked Reviewed-by tags (Thanks Evan!)
- Addressed comments on patch 3.

v3: https://lore.kernel.org/lkml/[e-mail]/
- New patch to add a pre_aggregate() callback.

v2: https://lore.kernel.org/lkml/[e-mail]/
- Store tag with the request. (Evan)
- Reorganize the code to save bandwidth values into buckets and use the
  tag as a bitfield. (Evan)
- Clear the aggregated values after icc_set().

v1: https://lore.kernel.org/lkml/[e-mail]/


David Dai (1):
  interconnect: qcom: Add tagging and wake/sleep support for sdm845

Georgi Djakov (2):
  interconnect: Add support for path tags
  interconnect: Add pre_aggregate() callback

 drivers/interconnect/core.c           |  27 ++++-
 drivers/interconnect/qcom/sdm845.c    | 141 ++++++++++++++++++++------
 include/linux/interconnect-provider.h |   7 +-
 include/linux/interconnect.h          |   5 +
 4 files changed, 145 insertions(+), 35 deletions(-)