diff mbox

[v10,10/10] drivers: qcom: rpmh-rsc: allow active requests from wake TCS

Message ID 1528737949-17495-11-git-send-email-rplsssn@codeaurora.org (mailing list archive)
State Superseded, archived
Delegated to: Andy Gross
Headers show

Commit Message

Raju P.L.S.S.S.N June 11, 2018, 5:25 p.m. UTC 
From: Lina Iyer <ilina@codeaurora.org>

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@codeaurora.org>
Signed-off-by: Raju P.L.S.S.S.N <rplsssn@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
---
Changes in v10:
	- return ERR_PTR if invalidate fails
Changes in v9:
	- invalidate again if -EAGAIN is returned by rpmh_rsc_invalidate
---
 drivers/soc/qcom/rpmh-rsc.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

Comments

Doug Anderson June 13, 2018, 9:09 p.m. UTC | #1 
Hi,

On Mon, Jun 11, 2018 at 10:25 AM, Raju P L S S S N
<rplsssn@codeaurora.org> wrote:
> @@ -148,7 +148,8 @@ int rpmh_rsc_invalidate(struct rsc_drv *drv)
>  static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>                                          const struct tcs_request *msg)
>  {
> -       int type;
> +       int type, ret;
> +       struct tcs_group *tcs;
>
>         switch (msg->state) {
>         case RPMH_ACTIVE_ONLY_STATE:
> @@ -164,7 +165,25 @@ 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)) {
> +                       ret = rpmh_rsc_invalidate(drv);
> +                       if (ret)
> +                               return ERR_PTR(ret);

In v9 you looped as long as the "ret" was -EAGAIN.  Now you're not.
Are all the callers setup to handle -EAGAIN or should you keep the
loop in for -EAGAIN?  I don't think callers handle this well.

...or is there some reason that EAGAIN can't happen in this call to
rpmh_rsc_invalidate()?


-Doug
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Lina Iyer June 14, 2018, 5:18 p.m. UTC | #2 
On Wed, Jun 13 2018 at 15:09 -0600, Doug Anderson wrote:
>Hi,
>
>On Mon, Jun 11, 2018 at 10:25 AM, Raju P L S S S N
><rplsssn@codeaurora.org> wrote:
>> @@ -148,7 +148,8 @@ int rpmh_rsc_invalidate(struct rsc_drv *drv)
>>  static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
>>                                          const struct tcs_request *msg)
>>  {
>> -       int type;
>> +       int type, ret;
>> +       struct tcs_group *tcs;
>>
>>         switch (msg->state) {
>>         case RPMH_ACTIVE_ONLY_STATE:
>> @@ -164,7 +165,25 @@ 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)) {
>> +                       ret = rpmh_rsc_invalidate(drv);
>> +                       if (ret)
>> +                               return ERR_PTR(ret);
>
>In v9 you looped as long as the "ret" was -EAGAIN.  Now you're not.
>Are all the callers setup to handle -EAGAIN or should you keep the
>loop in for -EAGAIN?  I don't think callers handle this well.
>
>...or is there some reason that EAGAIN can't happen in this call to
>rpmh_rsc_invalidate()?
>
>
Returning an error back to the caller is the right approach here. If the
invalidate fails, its mostly because, the TCS is busy or in use by an
external entity. Only the caller would be able to resolve the condition
and take corrective action.

-- Lina

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diff mbox

Patch

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index a68dcd1..c4f12fa 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -148,7 +148,8 @@  int rpmh_rsc_invalidate(struct rsc_drv *drv)
 static struct tcs_group *get_tcs_for_msg(struct rsc_drv *drv,
 					 const struct tcs_request *msg)
 {
-	int type;
+	int type, ret;
+	struct tcs_group *tcs;
 
 	switch (msg->state) {
 	case RPMH_ACTIVE_ONLY_STATE:
@@ -164,7 +165,25 @@  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)) {
+			ret = rpmh_rsc_invalidate(drv);
+			if (ret)
+				return ERR_PTR(ret);
+		}
+	}
+
+	return tcs;
 }
 
 static const struct tcs_request *get_req_from_tcs(struct rsc_drv *drv,