linux-kernel - Re: [PATCH v2 2/5] media: venus: add a routine to set venus state

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Message-ID: <CAAFQd5Bsh22v7jp8CAO-qQEa6kLk4Qws37DmLZUytAJbUjOCWw@mail.gmail.com>
Date:   Wed, 4 Jul 2018 19:08:59 +0900
From:   Tomasz Figa <tfiga@...omium.org>
To:     vgarodia@...eaurora.org
Cc:     Hans Verkuil <hverkuil@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Andy Gross <andy.gross@...aro.org>, bjorn.andersson@...aro.org,
        Stanimir Varbanov <stanimir.varbanov@...aro.org>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        linux-soc@...r.kernel.org, devicetree@...r.kernel.org,
        Alexandre Courbot <acourbot@...omium.org>,
        linux-media-owner@...r.kernel.org
Subject: Re: [PATCH v2 2/5] media: venus: add a routine to set venus state

On Wed, Jul 4, 2018 at 6:41 PM Vikash Garodia <vgarodia@...eaurora.org> wrote:
>
> On 2018-07-04 14:30, Tomasz Figa wrote:
> > On Wed, Jul 4, 2018 at 4:59 PM Vikash Garodia <vgarodia@...eaurora.org>
> > wrote:
> >> On 2018-06-04 18:24, Tomasz Figa wrote:
> >> > On Sat, Jun 2, 2018 at 6:21 AM Jordan Crouse <jcrouse@...eaurora.org>
> >> > wrote:
> >> >> On Sat, Jun 02, 2018 at 01:56:05AM +0530, Vikash Garodia wrote:
> >> > Given that this function is supposed to substitute existing calls into
> >> > qcom_scm_set_remote_state(), why not just do something like this:
> >> >
> >> >         if (qcom_scm_is_available())
> >> >                 return qcom_scm_set_remote_state(state, 0);
> >> >
> >> >         switch (state) {
> >> >         case TZBSP_VIDEO_SUSPEND:
> >> >                 writel_relaxed(1, reg_base + WRAPPER_A9SS_SW_RESET);
> >> >                 break;
> >> >         case TZBSP_VIDEO_RESUME:
> >> >                 venus_reset_hw(core);
> >> >                 break;
> >> >         }
> >> >
> >> >         return 0;
> >> This will not work as driver will write on the register irrespective
> >> of
> >> scm
> >> availability.
> >
> > I'm sorry, where would it do so? The second line returns from the
> > function inf SCM is available, so the rest of the function wouldn't be
> > executed.
>
> Ah!! you are right. That would work as well.
> I am ok with either way, but would recommend to keep it the existing way
> as it makes it little more readable.

I personally think the early exit is more readable, as it clearly
separates the SCM and non-SCM part.

Best regards,
Tomasz