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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 13 Jan 2020 12:36:18 +0100
Message-ID: <CAK8P3a2u6s4MAM_9bOqSt5NwVc4XrXs9W36tp-7rWWTXx0+pRg@mail.gmail.com>
Subject: Re: [PATCH V2] firmware: arm_scmi: Make scmi core independent of
 transport type
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Sudeep Holla <sudeep.holla@arm.com>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        cristian.marussi@arm.com, peng.fan@nxp.com,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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On Mon, Jan 13, 2020 at 7:42 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 10-01-20, 12:15, Arnd Bergmann wrote:
> > On Fri, Jan 10, 2020 at 10:43 AM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> >
> > Simply dropping the __iomem isn't much better, now you get other
> > type mismatches.
>
> Right. So what exactly do you suggest I should do now? Drop __iomem
> from the structure's payload field but keep all local variables and
> function arguments with __iomem ?

> > > +struct scmi_chan_info {
> > > +       void *payload;
> > > +       struct device *dev;
> > > +       struct scmi_handle *handle;
> > > +       void *transport_info;
> > > +};
> >
> > Maybe you can wrap the scmi_chan_info inside of another
> > structure that contains  the payload pointer, and use container_of
> > to convert between them?
>
> We don't need to convert between the two of them, isn't it ? Are you
> referring some other field here ?

> > It's not obvious which parts of the structure should be shared and
> > which are transport specific.
>
> All transport specific information is kept in the transport specific
> structure which is saved here in the transport_info field. Is there
> something else that isn't clear ?

To answer all three, what I meant is that the payload pointer appears
to be transport specific and should not be part of the common
structure if there is generic way to access it.

      Arnd