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From: Doug Anderson <dianders@chromium.org>
To: Maulik Shah <mkshah@codeaurora.org>
Cc: Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Rajendra Nayak <rnayak@codeaurora.org>,
	Evan Green <evgreen@chromium.org>,
	Lina Iyer <ilina@codeaurora.org>,
	Stephen Boyd <swboyd@chromium.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFT PATCH v2 07/10] drivers: qcom: rpmh-rsc: Warning if tcs_write() used for non-active
Date: Thu, 2 Apr 2020 13:19:38 -0700
Message-ID: <CAD=FV=VMt+jQPX8hXBJkNGafEr_+r2p1hbFkG3LHeX9JjPCvrg@mail.gmail.com> (raw)
In-Reply-To: <339a7a7b-af4e-d6a9-4b48-2a603ea10172@codeaurora.org>

Hi,

On Wed, Apr 1, 2020 at 5:40 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> Hi,
>
> On 3/12/2020 4:43 AM, Douglas Anderson wrote:
> > tcs_write() is documented to only be useful for writing
> > RPMH_ACTIVE_ONLY_STATE.  Let's be loud if someone messes up.
> >
> > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > ---
> >
> > Changes in v2: None
> >
> >   drivers/soc/qcom/rpmh-rsc.c | 6 ++++++
> >   1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> > index 93f5d1fb71ca..ba489d18c20e 100644
> > --- a/drivers/soc/qcom/rpmh-rsc.c
> > +++ b/drivers/soc/qcom/rpmh-rsc.c
> > @@ -573,6 +573,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
> >       unsigned long flags;
> >       int ret;
> >
> > +     /*
> > +      * It only makes sense to grab a whole TCS for ourselves if we're
> > +      * triggering right away, which we only do for ACTIVE_ONLY.
> > +      */
> > +     WARN_ON(msg->state != RPMH_ACTIVE_ONLY_STATE);
> > +
>
> Unnecessary check, we will never hit this warning. Lets not add such check.

That's fine.  I can drop it, especially now that comments explain that
this is only for ACTIVE_ONLY.  Personally I like having extra
assertion failures like this that indicate a serious internal logic
error in the code, but I won't push strongly for it.


> Saying that you can modify this change to drop below check  from
> rpmh_rsc_write_ctrl_data() as that never hit.
>
>          /* Data sent to this API will not be sent immediately */
>          if (msg->state == RPMH_ACTIVE_ONLY_STATE)
>                  return -EINVAL;
>
> we always call rpmh_rsc_write_ctrl_data() for RPMH_SLEEP_STATE and
> RPMH_WAKE_ONLY_STATE.

Sure.  My preference would have been to change it to a WARN_ON() too
(because it signifies an internal error within the RPMH driver, not an
external error that a client of RPMH could trigger), but I can just
drop it entirely.


-Doug

  reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-11 23:13 [RFT PATCH v2 00/10] drivers: qcom: rpmh-rsc: Cleanup / add lots of comments Douglas Anderson
2020-03-11 23:13 ` [RFT PATCH v2 01/10] drivers: qcom: rpmh-rsc: Clean code reading/writing regs/cmds Douglas Anderson
2020-04-01  8:12   ` Maulik Shah
2020-03-11 23:13 ` [RFT PATCH v2 02/10] drivers: qcom: rpmh-rsc: Document the register layout better Douglas Anderson
2020-04-01  8:14   ` Maulik Shah
2020-04-02 20:15     ` Doug Anderson
2020-03-11 23:13 ` [RFT PATCH v2 03/10] drivers: qcom: rpmh-rsc: Fold tcs_ctrl_write() into its single caller Douglas Anderson
2020-04-01  8:17   ` Maulik Shah
2020-03-11 23:13 ` [RFT PATCH v2 04/10] drivers: qcom: rpmh-rsc: Remove get_tcs_of_type() abstraction Douglas Anderson
2020-04-01  8:18   ` Maulik Shah
2020-03-11 23:13 ` [RFT PATCH v2 05/10] drivers: qcom: rpmh-rsc: A lot of comments Douglas Anderson
2020-04-01 11:29   ` Maulik Shah
2020-04-02 20:18     ` Doug Anderson
2020-04-08 11:10       ` Maulik Shah
2020-03-11 23:13 ` [RFT PATCH v2 06/10] drivers: qcom: rpmh-rsc: Comment tcs_is_free() + warn if state mismatch Douglas Anderson
2020-04-01 11:38   ` Maulik Shah
2020-04-02 20:19     ` Doug Anderson
2020-03-11 23:13 ` [RFT PATCH v2 07/10] drivers: qcom: rpmh-rsc: Warning if tcs_write() used for non-active Douglas Anderson
2020-04-01 12:40   ` Maulik Shah
2020-04-02 20:19     ` Doug Anderson [this message]
2020-03-11 23:13 ` [RFT PATCH v2 08/10] drivers: qcom: rpmh-rsc: spin_lock_irqsave() for tcs_invalidate() Douglas Anderson
2020-03-26 21:44   ` Doug Anderson
2020-03-11 23:13 ` [RFT PATCH v2 09/10] drivers: qcom: rpmh-rsc: Kill cmd_cache and find_match() with fire Douglas Anderson
2020-03-11 23:13 ` [RFT PATCH v2 10/10] drivers: qcom: rpmh-rsc: Always use -EAGAIN, never -EBUSY Douglas Anderson

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