Cc: Rob, devicetree ML On 29.05.2020 18:31, Sylwester Nawrocki wrote: > This patchset adds interconnect API support for the Exynos SoC "samsung, > exynos-bus" compatible devices, which already have their corresponding > exynos-bus driver in the devfreq subsystem. Complementing the devfreq driver > with an interconnect functionality allows to ensure the QoS requirements > of devices accessing the system memory (e.g. video processing devices) > are fulfilled and to avoid issues like the one discussed in thread [1]. > > This patch series depends on 3 patches from Artur for the interconnect API > [2], which introduce following changes: > > - exporting of_icc_get_from_provider() to avoid hard coding every graph > edge in the DT or driver source, > - relaxing the requirement on #interconnect-cells, so there is no need > to provide dummy node IDs in the DT, > - adding new field in struct icc_provider to explicitly allow configuring > node pairs from two different providers. > > This series adds implementation of interconnect provider per each "samsung, > exynos-bus" compatible DT node, with one interconnect node per provider. > The interconnect code which was previously added as a part of the devfreq > driver has been converted to a separate platform driver. In the devfreq > a corresponding virtual child platform device is registered. Integration > of devfreq and interconnect frameworks is achieved through the PM QoS API. > > A sample interconnect consumer for exynos-mixer is added in patches 5/6, > 6/6, it is currently added only for exynos4412 and allows to address the > mixer DMA underrun error issues [1]. > > The series has been tested on Odroid U3 board. It is based on icc-next > branch with devfreq-next branch merged and patches [2] applied. > > -- > Regards, > Sylwester > > -- > Changes since v3 [3] (v4 skipped to align with patchset [1]), detailed > changes are listed at each patch: > - conversion to a separate interconnect (platform) driver, > - an update of the DT binding documenting new optional properties: > #interconnect-cells, samsung,interconnect-parent in "samsung,exynos-bus" > nodes, > - new DT properties added to the SoC, rather than to the board specific > files. > > Changes since v2 [5]: > - Use icc_std_aggregate(). > - Implement a different modification of apply_constraints() in > drivers/interconnect/core.c (patch 03). > - Use 'exynos,interconnect-parent-node' in the DT instead of > 'devfreq'/'parent', depending on the bus. > - Rebase on DT patches that deprecate the 'devfreq' DT property. > - Improve error handling, including freeing generated IDs on failure. > - Remove exynos_bus_icc_connect() and add exynos_bus_icc_get_parent(). > > Changes since v1 [4]: > - Rebase on coupled regulators patches. > - Use dev_pm_qos_*() API instead of overriding frequency in > exynos_bus_target(). > - Use IDR for node ID allocation. > - Reverse order of multiplication and division in > mixer_set_memory_bandwidth() (patch 07) to avoid integer overflow. > > > References: > [1] https://patchwork.kernel.org/patch/10861757/ (original issue) > [2] https://www.spinics.net/lists/linux-samsung-soc/msg70014.html > [3] https://lore.kernel.org/linux-pm/20191220115653.6487-1-a.swigon@xxxxxxxxxxx > [4] https://patchwork.kernel.org/cover/11054417/ (v1 of this RFC) > [5] https://patchwork.kernel.org/cover/11152595/ (v2 of this RFC) > > > Artur Świgoń (1): > ARM: dts: exynos: Add interconnects to Exynos4412 mixer > > Marek Szyprowski (1): > drm: exynos: mixer: Add interconnect support > > Sylwester Nawrocki (4): > dt-bindings: exynos-bus: Add documentation for interconnect properties > interconnect: Add generic interconnect driver for Exynos SoCs > PM / devfreq: exynos-bus: Add registration of interconnect child > device > ARM: dts: exynos: Add interconnect properties to Exynos4412 bus nodes > > .../devicetree/bindings/devfreq/exynos-bus.txt | 15 +- > arch/arm/boot/dts/exynos4412.dtsi | 6 + > drivers/devfreq/exynos-bus.c | 17 ++ > drivers/gpu/drm/exynos/exynos_mixer.c | 73 +++++++- > drivers/interconnect/Kconfig | 1 + > drivers/interconnect/Makefile | 1 + > drivers/interconnect/exynos/Kconfig | 6 + > drivers/interconnect/exynos/Makefile | 4 + > drivers/interconnect/exynos/exynos.c | 185 +++++++++++++++++++++ > 9 files changed, 301 insertions(+), 7 deletions(-) > create mode 100644 drivers/interconnect/exynos/Kconfig > create mode 100644 drivers/interconnect/exynos/Makefile > create mode 100644 drivers/interconnect/exynos/exynos.c
