[v3,0/3] Add interconnect sync state support

Message

Georgi Djakov Aug. 25, 2020, 5:01 p.m. UTC

Bootloaders often leave some system resources enabled such as clocks,
regulators, interconnects etc. We want to keep these resources enabled
until all their consumers are probed. These resources are often shared,
so we must wait for all the consumers to come up, before deciding
whether to turn them off or change the configuration. This patchset is
trying to solve the above problem just for the on-chip interconnects.

The problem is solved by allowing the providers to implement the get_bw()
function which should return the current average/peak bandwidth. These are
used as floor values, that are enforced during boot while the requests from
all consumers are being collected. Then the sync_state() callback is used
to signal that all consumers have been probed, meaning that the floor
bandwidth is not needed anymore and the framework is ready to re-aggregate
and process all requests. If get_bw() is not implemented, the framework
will use INT_MAX as default bandwidth value.

v3:
* Go back to introducing the get_bw() function as in v1. (Saravana)
* If querying the current bandwidth is not supported, max out the
  bandwidth. (Saravana)
* Use icc_sync_state also for sc7180.

v2: https://lore.kernel.org/r/[e-mail]/
* Support initial values for both average and peak bandwidth (Mike)
* Skip aggregating/setting for nodes that don't specify initial bw (Mike)
* Drop patch 2/4: Add get_bw() callback (Mike)
* Squash patches 3 and 4.

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

Georgi Djakov (3):
  interconnect: Add get_bw() callback
  interconnect: Add sync state support
  interconnect: qcom: Use icc_sync_state

 drivers/interconnect/core.c           | 67 +++++++++++++++++++++++++++
 drivers/interconnect/qcom/osm-l3.c    |  1 +
 drivers/interconnect/qcom/sc7180.c    |  1 +
 drivers/interconnect/qcom/sdm845.c    |  1 +
 include/linux/interconnect-provider.h |  7 +++
 5 files changed, 77 insertions(+)

Comments

Saravana Kannan Sept. 18, 2020, 12:43 a.m. UTC | #1

Reviewed-by: Saravana Kannan <[e-mail]>

to all 3 patches in the series.

-Saravana

On Tue, Aug 25, 2020 at 10:01 AM Georgi Djakov <[e-mail]> wrote:
>
> Bootloaders often leave some system resources enabled such as clocks,
> regulators, interconnects etc. We want to keep these resources enabled
> until all their consumers are probed. These resources are often shared,
> so we must wait for all the consumers to come up, before deciding
> whether to turn them off or change the configuration. This patchset is
> trying to solve the above problem just for the on-chip interconnects.
>
> The problem is solved by allowing the providers to implement the get_bw()
> function which should return the current average/peak bandwidth. These are
> used as floor values, that are enforced during boot while the requests from
> all consumers are being collected. Then the sync_state() callback is used
> to signal that all consumers have been probed, meaning that the floor
> bandwidth is not needed anymore and the framework is ready to re-aggregate
> and process all requests. If get_bw() is not implemented, the framework
> will use INT_MAX as default bandwidth value.
>
> v3:
> * Go back to introducing the get_bw() function as in v1. (Saravana)
> * If querying the current bandwidth is not supported, max out the
>   bandwidth. (Saravana)
> * Use icc_sync_state also for sc7180.
>
> v2: https://lore.kernel.org/r/[e-mail]/
> * Support initial values for both average and peak bandwidth (Mike)
> * Skip aggregating/setting for nodes that don't specify initial bw (Mike)
> * Drop patch 2/4: Add get_bw() callback (Mike)
> * Squash patches 3 and 4.
>
> v1: https://lore.kernel.org/lkml/[e-mail]/
>
> Georgi Djakov (3):
>   interconnect: Add get_bw() callback
>   interconnect: Add sync state support
>   interconnect: qcom: Use icc_sync_state
>
>  drivers/interconnect/core.c           | 67 +++++++++++++++++++++++++++
>  drivers/interconnect/qcom/osm-l3.c    |  1 +
>  drivers/interconnect/qcom/sc7180.c    |  1 +
>  drivers/interconnect/qcom/sdm845.c    |  1 +
>  include/linux/interconnect-provider.h |  7 +++
>  5 files changed, 77 insertions(+)
>