linux-kernel - Re: [PATCH v8 10/10] drivers: qcom: rpmh-rsc: allow active requests from wake TCS

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Date:   Wed, 23 May 2018 19:51:05 +0530
From:   Raju P L S S S N <rplsssn@...eaurora.org>
To:     Doug Anderson <dianders@...omium.org>,
        Lina Iyer <ilina@...eaurora.org>
Cc:     Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        linux-arm-msm@...r.kernel.org,
        "open list:ARM/QUALCOMM SUPPORT" <linux-soc@...r.kernel.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        msivasub@...eaurora.org, mkshah@...eaurora.org,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Evan Green <evgreen@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>
Subject: Re: [PATCH v8 10/10] drivers: qcom: rpmh-rsc: allow active requests
 from wake TCS

Hi,

On 5/12/2018 1:47 AM, Doug Anderson wrote:
> Hi,
> 
> On Wed, May 9, 2018 at 10:01 AM, Lina Iyer <ilina@...eaurora.org> wrote:
>> Some RSCs may only have sleep and wake TCS, i.e, there is no dedicated
>> TCS for active mode request, but drivers may still want to make active
>> requests from these RSCs. In such cases re-purpose the wake TCS to send
>> active state requests.
>>
>> The requirement for this is that the driver is aware that the wake TCS
>> is being repurposed to send active request, hence the sleep and wake
>> TCSes be invalidated before the active request is sent.
>>
>> Signed-off-by: Lina Iyer <ilina@...eaurora.org>
>> Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
>> ---
>>   drivers/soc/qcom/rpmh-rsc.c | 18 +++++++++++++++++-
>>   1 file changed, 17 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
>> index 68c25ebbbe09..369b9b3eedc5 100644
>> --- a/drivers/soc/qcom/rpmh-rsc.c
>> +++ b/drivers/soc/qcom/rpmh-rsc.c
>> @@ -153,6 +153,7 @@ static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>>                                           const struct tcs_request *msg)
>>   {
>>          int type;
>> +       struct tcs_group *tcs;
>>
>>          switch (msg->state) {
>>          case RPMH_ACTIVE_ONLY_STATE:
>> @@ -168,7 +169,22 @@ static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>>                  return ERR_PTR(-EINVAL);
>>          }
>>
>> -       return get_tcs_of_type(drv, type);
>> +       /*
>> +        * If we are making an active request on a RSC that does not have a
>> +        * dedicated TCS for active state use, then re-purpose a wake TCS to
>> +        * send active votes.
>> +        * NOTE: The driver must be aware that this RSC does not have a
>> +        * dedicated AMC, and therefore would invalidate the sleep and wake
>> +        * TCSes before making an active state request.
>> +        */
>> +       tcs = get_tcs_of_type(drv, type);
>> +       if (msg->state == RPMH_ACTIVE_ONLY_STATE && IS_ERR(tcs)) {
>> +               tcs = get_tcs_of_type(drv, WAKE_TCS);
>> +               if (!IS_ERR(tcs))
>> +                       rpmh_rsc_invalidate(drv);
> 
> I noticed that rpmh_rsc_invalidate() can return -EAGAIN.  Do you need
> to deal with that here?

Yes. will add the check here.

Thanks,
Raju.

> 
> 
> -Doug
>