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 is achieved by using dev_pm_qos_*() API[5]. 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. This patchset depends on [5]. --- Changes since v1 [6]: * Rebase on [4] (coupled regulators). * Rebase on [5] (dev_pm_qos for devfreq). * Use dev_pm_qos_*() API[5] instead of overriding frequency in exynos_bus_target(). * Use IDR for node ID allocation. * Avoid goto in functions extracted in patches 01 & 02 (cf. patch 04). * Reverse order of multiplication and division in mixer_set_memory_bandwidth() (patch 11) to avoid integer overflow. --- 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/ (original issue) [4] https://patchwork.kernel.org/cover/11083663/ (coupled regulators; merged) [5] https://patchwork.kernel.org/cover/11149497/ (dev_pm_qos for devfreq) [6] https://patchwork.kernel.org/cover/11054417/ (v1 of this RFC) 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 interconnect: Export of_icc_get_from_provider() interconnect: Relax requirement in of_icc_get_from_provider() interconnect: 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 | 319 +++++++++++++----- drivers/gpu/drm/exynos/exynos_mixer.c | 71 +++- drivers/interconnect/core.c | 12 +- include/linux/interconnect-provider.h | 6 + 6 files changed, 327 insertions(+), 92 deletions(-) -- 2.17.1
