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From: Rob Clark <robdclark@gmail.com>
Date: Tue, 19 Dec 2017 10:21:01 -0500
Message-ID: <CAF6AEGsMKMfDz=C6n5Fw0Fo92nu6qHXMV1w4rvE+6EhfTW6huA@mail.gmail.com>
Subject: Re: [PATCH v3 1/3] interconnect: Add generic on-chip interconnect API
To: Georgi Djakov <georgi.djakov@linaro.org>
Cc: linux-pm@vger.kernel.org, Greg KH <gregkh@linuxfoundation.org>,
        Rafael Wysocki <rjw@rjwysocki.net>, Rob Herring <robh+dt@kernel.org>,
        Kevin Hilman <khilman@baylibre.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Saravana Kannan <skannan@codeaurora.org>,
        Stephen Boyd <sboyd@codeaurora.org>,
        Andy Gross <andy.gross@linaro.org>, seansw@qti.qualcomm.com,
        davidai@quicinc.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-kernel@lists.infradead.org,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Mark Rutland <mark.rutland@arm.com>, lorenzo.pieralisi@arm.com
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On Fri, Sep 8, 2017 at 1:18 PM, Georgi Djakov <georgi.djakov@linaro.org> wrote:
> This patch introduce a new API to get requirements and configure the
> interconnect buses across the entire chipset to fit with the current demand.
>
> The API is using a consumer/provider-based model, where the providers are
> the interconnect buses and the consumers could be various drivers.
> The consumers request interconnect resources (path) between endpoints and
> set the desired constraints on this data flow path. The providers receive
> requests from consumers and aggregate these requests for all master-slave
> pairs on that path. Then the providers configure each participating in the
> topology node according to the requested data flow path, physical links and
> constraints. The topology could be complicated and multi-tiered and is SoC
> specific.
>
> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
> ---
>  Documentation/interconnect/interconnect.rst |  93 +++++++
>  drivers/Kconfig                             |   2 +
>  drivers/Makefile                            |   1 +
>  drivers/interconnect/Kconfig                |  10 +
>  drivers/interconnect/Makefile               |   1 +
>  drivers/interconnect/interconnect.c         | 382 ++++++++++++++++++++++++++++
>  include/linux/interconnect-consumer.h       |  73 ++++++
>  include/linux/interconnect-provider.h       | 119 +++++++++
>  8 files changed, 681 insertions(+)
>  create mode 100644 Documentation/interconnect/interconnect.rst
>  create mode 100644 drivers/interconnect/Kconfig
>  create mode 100644 drivers/interconnect/Makefile
>  create mode 100644 drivers/interconnect/interconnect.c
>  create mode 100644 include/linux/interconnect-consumer.h
>  create mode 100644 include/linux/interconnect-provider.h
>
>

[snip]

> +/**
> + * interconnect_set() - set constraints on a path between two endpoints
> + * @path: reference to the path returned by interconnect_get()
> + * @creq: request from the consumer, containing its requirements
> + *
> + * This function is used by an interconnect consumer to express its own needs
> + * in term of bandwidth and QoS for a previously requested path between two
> + * endpoints. The requests are aggregated and each node is updated accordingly.
> + *
> + * Returns 0 on success, or an approproate error code otherwise.
> + */
> +int interconnect_set(struct interconnect_path *path,
> +                    struct interconnect_creq *creq)

drive-by comment... afaict creq could be 'const'

BR,
-R