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From:   Jassi Brar <jassisinghbrar@gmail.com>
Date:   Thu, 29 Sep 2022 12:37:12 -0500
Message-ID: <CABb+yY1qpMdvfEwAFphYJJVvAQiNj7_gRmkRk38xx_QXr_qPBA@mail.gmail.com>
Subject: Re: [PATCH v4 09/14] mailbox: Add Gunyah message queue mailbox
To:     Bjorn Andersson <andersson@kernel.org>
Cc:     Elliot Berman <quic_eberman@quicinc.com>,
        Bjorn Andersson <quic_bjorande@quicinc.com>,
        Murali Nalajala <quic_mnalajal@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>,
        Carl van Schaik <quic_cvanscha@quicinc.com>,
        Andy Gross <agross@kernel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        linux-arm-kernel@lists.infradead.org,
        Mark Rutland <mark.rutland@arm.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Marc Zyngier <maz@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Will Deacon <will@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
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On Thu, Sep 29, 2022 at 11:59 AM Bjorn Andersson <andersson@kernel.org> wrote:
>
> On Wed, Sep 28, 2022 at 12:56:28PM -0700, Elliot Berman wrote:
> [..]
> > diff --git a/drivers/mailbox/gunyah-msgq.c b/drivers/mailbox/gunyah-msgq.c
> [..]
> > +static int gh_msgq_send_data(struct mbox_chan *chan, void *data)
> > +{
> > +     struct gunyah_msgq *msgq = mbox_chan_to_msgq(chan);
> > +     struct gunyah_msgq_tx_data *msgq_data = data;
>
> The mailbox framework abstracts hardware mailboxes and @data
> should be the data to be written to the hardware.
>
> Using the void * to pass composite data types means that the client and
> provider are tightly coupled and as such the mailbox framework does not
> provide you any abstraction.
>
It is so for every platform, because there is no "standard format" in
which data is to be exchanged between endpoints.
Mailbox api is used mainly to avoid redoing message queuing and
response handling.

cheers.