Re: [PATCH V2 2/2] firmware: arm_scmi: Skip adding bad duplicates

[Konrad Dybcio <konradybcio@kernel.org>]

On 4.09.2024 3:56 PM, Konrad Dybcio wrote:
> On 4.09.2024 5:13 AM, Sibi Sankar wrote:
>> Ensure that the bad duplicates reported by the platform firmware doesn't
>> get added to the opp-tables.
>>
>> Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
>> ---
>>  drivers/firmware/arm_scmi/perf.c | 13 +++++++++++--
>>  1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
>> index 2d77b5f40ca7..114c3dd70ede 100644
>> --- a/drivers/firmware/arm_scmi/perf.c
>> +++ b/drivers/firmware/arm_scmi/perf.c
>> @@ -386,9 +386,11 @@ process_response_opp(struct device *dev, struct perf_dom_info *dom,
>>  		le16_to_cpu(r->opp[loop_idx].transition_latency_us);
>>  
>>  	ret = xa_insert(&dom->opps_by_lvl, opp->perf, opp, GFP_KERNEL);
>> -	if (ret)
>> +	if (ret) {
>>  		dev_warn(dev, "Failed to add opps_by_lvl at %d for %s - ret:%d\n",
>>  			 opp->perf, dom->info.name, ret);
>> +		opp->perf = 0;
>> +	}
>>  }
>>  
>>  static inline void
>> @@ -404,9 +406,12 @@ process_response_opp_v4(struct device *dev, struct perf_dom_info *dom,
>>  		le16_to_cpu(r->opp[loop_idx].transition_latency_us);
>>  
>>  	ret = xa_insert(&dom->opps_by_lvl, opp->perf, opp, GFP_KERNEL);
>> -	if (ret)
>> +	if (ret) {
>>  		dev_warn(dev, "Failed to add opps_by_lvl at %d for %s - ret:%d\n",
>>  			 opp->perf, dom->info.name, ret);
>> +		opp->perf = 0;
>> +		return;
>> +	}
>>  
>>  	/* Note that PERF v4 reports always five 32-bit words */
>>  	opp->indicative_freq = le32_to_cpu(r->opp[loop_idx].indicative_freq);
>> @@ -871,6 +876,10 @@ static int scmi_dvfs_device_opps_add(const struct scmi_protocol_handle *ph,
>>  		else
>>  			freq = dom->opp[idx].indicative_freq * dom->mult_factor;
>>  
>> +		/* Skip all invalid frequencies reported by the firmware */
>> +		if (!freq)
>> +			continue;
> 
> Maybe something like this instead? (not tested)
> 
> diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
> index 2d77b5f40ca7..530692119c79 100644
> --- a/drivers/firmware/arm_scmi/perf.c
> +++ b/drivers/firmware/arm_scmi/perf.c
> @@ -431,8 +431,14 @@ iter_perf_levels_process_response(const struct scmi_protocol_handle *ph,
>  {
>         struct scmi_opp *opp;
>         struct scmi_perf_ipriv *p = priv;
> +       unsigned int idx = st->desc_index + st->loop_idx;
> +
> +       opp = &p->perf_dom->opp[idx];
> +
> +       /* Avoid duplicate entries coming from buggy firmware */
> +       if (idx > 0 && opp->perf && p->perf_dom->opp[idx - 1].perf)
> +               return 0;
>  
> -       opp = &p->perf_dom->opp[st->desc_index + st->loop_idx];
>         if (PROTOCOL_REV_MAJOR(p->version) <= 0x3)
>                 process_response_opp(ph->dev, p->perf_dom, opp, st->loop_idx,
>                                      response);

No that won't work, perf_dom->opp has all the entries and that's used
in e.g. scmi_dvfs_device_opps_add :/

Konrad