linux-kernel - Re: [PATCH v13 3/5] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes before flushing new data

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Date:   Mon, 9 Mar 2020 16:42:30 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Maulik Shah <mkshah@...eaurora.org>
Cc:     Stephen Boyd <swboyd@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Evan Green <evgreen@...omium.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Andy Gross <agross@...nel.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Lina Iyer <ilina@...eaurora.org>, lsrao@...eaurora.org
Subject: Re: [PATCH v13 3/5] soc: qcom: rpmh: Invalidate SLEEP and WAKE TCSes
 before flushing new data

Hi,

On Mon, Mar 9, 2020 at 2:31 AM Maulik Shah <mkshah@...eaurora.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.
>
> With this there is no need to invoke rpmh_rsc_invalidate() call from
> rpmh_invalidate().
>
> Simplify rpmh_invalidate() by moving invalidate_batch() inside.
>
> Fixes: 600513dfeef3 ("drivers: qcom: rpmh: cache sleep/wake state requests")
> Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
> ---
>  drivers/soc/qcom/rpmh.c | 36 +++++++++++++++---------------------
>  1 file changed, 15 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c
> index 03630ae..5bed8f4 100644
> --- a/drivers/soc/qcom/rpmh.c
> +++ b/drivers/soc/qcom/rpmh.c
> @@ -317,19 +317,6 @@ static int flush_batch(struct rpmh_ctrlr *ctrlr)
>         return ret;
>  }
>
> -static void invalidate_batch(struct rpmh_ctrlr *ctrlr)
> -{
> -       struct batch_cache_req *req, *tmp;
> -       unsigned long flags;
> -
> -       spin_lock_irqsave(&ctrlr->cache_lock, flags);
> -       list_for_each_entry_safe(req, tmp, &ctrlr->batch_cache, list)
> -               kfree(req);
> -       INIT_LIST_HEAD(&ctrlr->batch_cache);
> -       ctrlr->dirty = true;
> -       spin_unlock_irqrestore(&ctrlr->cache_lock, flags);
> -}
> -
>  /**
>   * rpmh_write_batch: Write multiple sets of RPMH commands and wait for the
>   * batch to finish.
> @@ -467,6 +454,11 @@ 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);
> +

You forgot to actually check the return value.

if (ret)
  return ret;


>         /* First flush the cached batch requests */
>         ret = flush_batch(ctrlr);
>         if (ret)
> @@ -503,19 +495,21 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr)
>   *
>   * @dev: The device making the request
>   *
> - * Invalidate the sleep and active values in the TCS blocks.
> + * Invalidate the sleep and wake values in batch_cache.

Thanks for updating this.  It was on my todo list.  Can you also
update the function description, which still says "Invalidate all
sleep and active sets sets."  While you're at it, remove the double
"sets".