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[v3,0/3] interconnect: Add path tagging support

Message ID 20190809121325.8138-1-georgi.djakov@linaro.org
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Series interconnect: Add path tagging support | expand

Message

Georgi Djakov Aug. 9, 2019, 12:13 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.

v3:
- New patch to add a pre_aggregate() callback.

v2: https://lore.kernel.org/lkml/20190618091724.28232-1-georgi.djakov@linaro.org/
- 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/20190208172152.1807-1-georgi.djakov@linaro.org/


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    | 136 ++++++++++++++++++++------
 include/linux/interconnect-provider.h |   7 +-
 include/linux/interconnect.h          |   5 +
 4 files changed, 140 insertions(+), 35 deletions(-)

Comments

Evan Green Aug. 9, 2019, 9:17 p.m. UTC | #1 
On Fri, Aug 9, 2019 at 5:13 AM Georgi Djakov <georgi.djakov@linaro.org> wrote:
>

> Introduce an optional callback in interconnect provider drivers. It can be

> used for implementing actions, that need to be executed before the actual

> aggregation of the bandwidth requests has started.

>

> The benefit of this for now is that it will significantly simplify the code

> in provider drivers.

>

> Suggested-by: Evan Green <evgreen@chromium.org>

> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>


Reviewed-by: Evan Green <evgreen@chromium.org>