Re: [PATCH 2/3] firmware: arm_scmi: Add support for marking certain frequencies as boost

Sudeep Holla
2024-01-31T16:08:54Z

On Wed, Jan 31, 2024 at 03:29:43PM +0100, Pierre Gondois wrote:
> Hello Sibi,
>
> On 1/17/24 12:04, Sibi Sankar wrote:
> > All opps above the sustained level/frequency are treated as boost, so mark
> > them accordingly.
> >
> > Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
> > Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
> > ---
> > drivers/firmware/arm_scmi/perf.c | 11 ++++++++++-
> > 1 file changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
> > index e286f04ee6e3..d3fb8c804b3d 100644
> > --- a/drivers/firmware/arm_scmi/perf.c
> > +++ b/drivers/firmware/arm_scmi/perf.c
> > @@ -811,7 +811,7 @@ static int scmi_dvfs_device_opps_add(const struct scmi_protocol_handle *ph,
> > struct device *dev, u32 domain)
> > {
> > int idx, ret;
> > - unsigned long freq;
> > + unsigned long freq, sustained_freq;
> > struct dev_pm_opp_data data = {};
> > struct perf_dom_info *dom;
> > @@ -819,12 +819,21 @@ static int scmi_dvfs_device_opps_add(const struct scmi_protocol_handle *ph,
> > if (IS_ERR(dom))
> > return PTR_ERR(dom);
> > + if (!dom->level_indexing_mode)
> > + sustained_freq = dom->sustained_perf_level * dom->mult_factor;
> > + else
> > + sustained_freq = dom->sustained_freq_khz * dom->mult_factor;
> > +
> > for (idx = 0; idx < dom->opp_count; idx++) {
> > if (!dom->level_indexing_mode)
> > freq = dom->opp[idx].perf * dom->mult_factor;
> > else
> > freq = dom->opp[idx].indicative_freq * dom->mult_factor;
> > + /* All opps above the sustained level/frequency are treated as boost */
> > + if (sustained_freq && freq > sustained_freq)
>
> It seems the sustained_freq is not optional since SCMI v1.0,
> is it necessary to check that (sustained_freq != 0) ?
>

Technically correct, we don't have to. But since day 1, we checked and
handled 0 for perf_level specifically to avoid division by zero. I am
just worried if there are any platforms in the wild with these values as
0. We can start without the check and add it if someone complains perhaps ?

--
Regards,
Sudeep