2020-03-11 23:16:01

by Doug Anderson

[permalink] [raw]
Subject: [RFT PATCH v2 07/10] drivers: qcom: rpmh-rsc: Warning if tcs_write() used for non-active

tcs_write() is documented to only be useful for writing
RPMH_ACTIVE_ONLY_STATE. Let's be loud if someone messes up.

Signed-off-by: Douglas Anderson <[email protected]>
---

Changes in v2: None

drivers/soc/qcom/rpmh-rsc.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 93f5d1fb71ca..ba489d18c20e 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -573,6 +573,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
unsigned long flags;
int ret;

+ /*
+ * It only makes sense to grab a whole TCS for ourselves if we're
+ * triggering right away, which we only do for ACTIVE_ONLY.
+ */
+ WARN_ON(msg->state != RPMH_ACTIVE_ONLY_STATE);
+
/* TODO: get_tcs_for_msg() can return -EAGAIN and nobody handles */
tcs = get_tcs_for_msg(drv, msg);
if (IS_ERR(tcs))
--
2.25.1.481.gfbce0eb801-goog


2020-04-01 12:41:16

by Maulik Shah

[permalink] [raw]
Subject: Re: [RFT PATCH v2 07/10] drivers: qcom: rpmh-rsc: Warning if tcs_write() used for non-active

Hi,

On 3/12/2020 4:43 AM, Douglas Anderson wrote:
> tcs_write() is documented to only be useful for writing
> RPMH_ACTIVE_ONLY_STATE. Let's be loud if someone messes up.
>
> Signed-off-by: Douglas Anderson <[email protected]>
> ---
>
> Changes in v2: None
>
> drivers/soc/qcom/rpmh-rsc.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> index 93f5d1fb71ca..ba489d18c20e 100644
> --- a/drivers/soc/qcom/rpmh-rsc.c
> +++ b/drivers/soc/qcom/rpmh-rsc.c
> @@ -573,6 +573,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
> unsigned long flags;
> int ret;
>
> + /*
> + * It only makes sense to grab a whole TCS for ourselves if we're
> + * triggering right away, which we only do for ACTIVE_ONLY.
> + */
> + WARN_ON(msg->state != RPMH_ACTIVE_ONLY_STATE);
> +

Unnecessary check, we will never hit this warning. Lets not add such check.

Saying that you can modify this change to drop below check  from
rpmh_rsc_write_ctrl_data() as that never hit.

        /* Data sent to this API will not be sent immediately */
        if (msg->state == RPMH_ACTIVE_ONLY_STATE)
                return -EINVAL;

we always call rpmh_rsc_write_ctrl_data() for RPMH_SLEEP_STATE and
RPMH_WAKE_ONLY_STATE.

Thanks,
Maulik
> /* TODO: get_tcs_for_msg() can return -EAGAIN and nobody handles */
> tcs = get_tcs_for_msg(drv, msg);
> if (IS_ERR(tcs))

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

2020-04-02 20:21:06

by Doug Anderson

[permalink] [raw]
Subject: Re: [RFT PATCH v2 07/10] drivers: qcom: rpmh-rsc: Warning if tcs_write() used for non-active

Hi,

On Wed, Apr 1, 2020 at 5:40 AM Maulik Shah <[email protected]> wrote:
>
> Hi,
>
> On 3/12/2020 4:43 AM, Douglas Anderson wrote:
> > tcs_write() is documented to only be useful for writing
> > RPMH_ACTIVE_ONLY_STATE. Let's be loud if someone messes up.
> >
> > Signed-off-by: Douglas Anderson <[email protected]>
> > ---
> >
> > Changes in v2: None
> >
> > drivers/soc/qcom/rpmh-rsc.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
> > index 93f5d1fb71ca..ba489d18c20e 100644
> > --- a/drivers/soc/qcom/rpmh-rsc.c
> > +++ b/drivers/soc/qcom/rpmh-rsc.c
> > @@ -573,6 +573,12 @@ static int tcs_write(struct rsc_drv *drv, const struct tcs_request *msg)
> > unsigned long flags;
> > int ret;
> >
> > + /*
> > + * It only makes sense to grab a whole TCS for ourselves if we're
> > + * triggering right away, which we only do for ACTIVE_ONLY.
> > + */
> > + WARN_ON(msg->state != RPMH_ACTIVE_ONLY_STATE);
> > +
>
> Unnecessary check, we will never hit this warning. Lets not add such check.

That's fine. I can drop it, especially now that comments explain that
this is only for ACTIVE_ONLY. Personally I like having extra
assertion failures like this that indicate a serious internal logic
error in the code, but I won't push strongly for it.


> Saying that you can modify this change to drop below check from
> rpmh_rsc_write_ctrl_data() as that never hit.
>
> /* Data sent to this API will not be sent immediately */
> if (msg->state == RPMH_ACTIVE_ONLY_STATE)
> return -EINVAL;
>
> we always call rpmh_rsc_write_ctrl_data() for RPMH_SLEEP_STATE and
> RPMH_WAKE_ONLY_STATE.

Sure. My preference would have been to change it to a WARN_ON() too
(because it signifies an internal error within the RPMH driver, not an
external error that a client of RPMH could trigger), but I can just
drop it entirely.


-Doug