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From:   Doug Anderson <dianders@chromium.org>
Date:   Thu, 5 Mar 2020 14:20:38 -0800
Message-ID: <CAD=FV=U8zaZCTrZvtipSmaQL8NGg+4aNpyP=KhQ5EYioKovnYA@mail.gmail.com>
Subject: Re: [PATCH v12 4/4] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes
 before flushing new data
To:     Maulik Shah <mkshah@codeaurora.org>
Cc:     Stephen Boyd <swboyd@chromium.org>,
        Matthias Kaehlcke <mka@chromium.org>,
        Evan Green <evgreen@chromium.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Andy Gross <agross@kernel.org>,
        Rajendra Nayak <rnayak@codeaurora.org>,
        Lina Iyer <ilina@codeaurora.org>, lsrao@codeaurora.org
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Sender: linux-kernel-owner@vger.kernel.org
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Hi,

On Thu, Mar 5, 2020 at 9:07 AM Maulik Shah <mkshah@codeaurora.org> wrote:
>
> TCSes have previously programmed data when rpmh_flush is called.
> This can cause old data to trigger along with newly flushed.
>
> Fix this by cleaning SLEEP and WAKE TCSes before new data is flushed.
>
> Fixes: 600513dfeef3 ("drivers: qcom: rpmh: cache sleep/wake state requests")
> Signed-off-by: Maulik Shah <mkshah@codeaurora.org>
> ---
>  drivers/soc/qcom/rpmh.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
> index 1951f6a..63364ce 100644
> --- a/drivers/soc/qcom/rpmh.c
> +++ b/drivers/soc/qcom/rpmh.c
> @@ -472,6 +472,11 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
>                 return 0;
>         }
>
> +       /* Invalidate the TCSes first to avoid stale data */
> +       do {
> +               ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr));
> +       } while (ret == -EAGAIN);
> +
>         /* First flush the cached batch requests */
>         ret = flush_batch(ctrlr);
>         if (ret)

I think you should make this patch 3/4 instead of 4/4, and then:

1. In this patch remove the call to rpmh_rsc_invalidate() in
rpmh_invalidate().  You've already marked things "dirty" in
invalidate_batch() so no need to actually program the hardware--it'll
happen in the flush.

2. In patch 4/4 (the flushing patch) add a call to rpmh_flush() to
rpmh_invalidate() if you're in non-OSI mode.  Presumably you'll need a
spinlock around the rpmh_flush() call?


The end result of that will be that rpmh_invalidate() will properly
leave the non-batch sleep/wake sets programmed.


-Doug