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

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Date:   Tue, 10 Mar 2020 16:39:38 +0530
From:   Maulik Shah <mkshah@...eaurora.org>
To:     Doug Anderson <dianders@...omium.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


On 3/10/2020 5:12 AM, Doug Anderson wrote:
> 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;
Done.
>
>>         /* 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".

Done.

Thanks,
Maulik

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