[RFC PATCH 00/11] Simple QoS for exynos-bus driver using interconnect

[Chanwoo Choi]

Hi Artur.

The patch1-4 in this series depend on other patches[1] on mainline.
On next v2 version, please make some patches based on patches[1]
in order to prevent the merge conflict. 

[1] [RESEND PATCH v5 0/4] add coupled regulators for Exynos5422/5800
- https://lkml.org/lkml/2019/8/8/217

Also, as I commented, we better to discuss it before sending the v2.

On 19. 7. 23. 오후 9:20, Artur Świgoń wrote:
> The following patchset adds interconnect[1][2] framework support to the
> exynos-bus devfreq driver. Extending the devfreq driver with interconnect
> capabilities started as a response to the issue referenced in [3]. The
> patches can be subdivided into four logical groups:
> 
> (a) Refactoring the existing devfreq driver in order to improve readability
> and accommodate for adding new code (patches 01--04/11).
> 
> (b) Tweaking the interconnect framework to support the exynos-bus use case
> (patches 05--07/11). Exporting of_icc_get_from_provider() allows us to
> avoid hardcoding every single graph edge in the DT or driver source, and
> relaxing the requirement contained in that function removes the need to
> provide dummy node IDs in the DT. Adjusting the logic in
> apply_constraints() (drivers/interconnect/core.c) accounts for the fact
> that every bus is a separate entity and therefore a separate interconnect
> provider, albeit constituting a part of a larger hierarchy.
> 
> (c) Implementing interconnect providers in the exynos-bus devfreq driver
> and adding required DT properties for one selected platform, namely
> Exynos4412 (patches 08--09/11). Due to the fact that this aims to be a
> generic driver for various Exynos SoCs, node IDs are generated dynamically
> rather than hardcoded. This has been determined to be a simpler approach,
> but depends on changes described in (b).
> 
> (d) Implementing a sample interconnect consumer for exynos-mixer targeted
> at the issue referenced in [3], again with DT info only for Exynos4412
> (patches 10--11/11).
> 
> Integration of devfreq and interconnect functionalities comes down to one
> extra line in the devfreq target() callback, which selects either the
> frequency calculated by the devfreq governor, or the one requested with the
> interconnect API, whichever is higher. All new code works equally well when
> CONFIG_INTERCONNECT is 'n' (as in exynos_defconfig) in which case all
> interconnect API functions are no-ops.
> 
> ---
> Artur Świgoń
> Samsung R&D Institute Poland
> Samsung Electronics
> 
> ---
> References:
> [1] Documentation/interconnect/interconnect.rst
> [2] Documentation/devicetree/bindings/interconnect/interconnect.txt
> [3] https://patchwork.kernel.org/patch/10861757
> 
> Artur Świgoń (10):
>   devfreq: exynos-bus: Extract exynos_bus_profile_init()
>   devfreq: exynos-bus: Extract exynos_bus_profile_init_passive()
>   devfreq: exynos-bus: Change goto-based logic to if-else logic
>   devfreq: exynos-bus: Clean up code
>   icc: Export of_icc_get_from_provider()
>   icc: Relax requirement in of_icc_get_from_provider()
>   icc: Relax condition in apply_constraints()
>   arm: dts: exynos: Add parents and #interconnect-cells to Exynos4412
>   devfreq: exynos-bus: Add interconnect functionality to exynos-bus
>   arm: dts: exynos: Add interconnects to Exynos4412 mixer
> 
> Marek Szyprowski (1):
>   drm: exynos: mixer: Add interconnect support
> 
>  .../boot/dts/exynos4412-odroid-common.dtsi    |   1 +
>  arch/arm/boot/dts/exynos4412.dtsi             |  10 +
>  drivers/devfreq/exynos-bus.c                  | 296 ++++++++++++++----
>  drivers/gpu/drm/exynos/exynos_mixer.c         |  68 +++-
>  drivers/interconnect/core.c                   |  12 +-
>  include/linux/interconnect-provider.h         |   6 +
>  6 files changed, 314 insertions(+), 79 deletions(-)
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics