Re: [RFC v3 8/8] wifi: mac80211: add wiphy radio assignment and validation

[Felix Fietkau <nbd@nbd.name>]

On 07.06.24 11:44, Johannes Berg wrote:
> On Thu, 2024-06-06 at 20:07 +0200, Felix Fietkau wrote:
>> 
>> +static bool
>> +ieee80211_radio_freq_match(const struct wiphy_radio *radio,
>> +			   const struct ieee80211_chan_req *chanreq)
>> +{
>> +	const struct wiphy_radio_freq_range *r;
>> +	u32 freq;
>> +	int i;
>> +
>> +	freq = ieee80211_channel_to_khz(chanreq->oper.chan);
>> +	for (i = 0; i < radio->n_freq_range; i++) {
>> +		r = &radio->freq_range[i];
>> +		if (freq >= r->start_freq && freq <= r->end_freq)
>> +			return true;
> 
> IMHO should be inclusive only on one side of the range. Can always make
> it work since channels are at least a few MHz apart, but the purist in
> me says it's easier to grok if the end is not inclusive :)

Sure, no problem.

> Maybe this should be a cfg80211 helper like
> 
> struct wiphy_radio *wiphy_get_radio(struct wiphy *wiphy, ... *chandef);

I didn't add such a helper, in case we get hardware where multiple 
radios support the same band. That's why ieee80211_find_available_radio 
loops over all radios until it finds one that matches both the freq 
range and the ifcomb constraints.

> which could also check that the _whole_ chandef fits (though that should
> probably also be handled elsewhere, like chandef_valid), and you can use
> it to get the radio pointer and then check for == below.
> 
> The point would be to have a single place with this kind of range logic.
> This is only going to get done by mac80211 now, but it'd really be
> awkward if some other driver had some other logic later.

I will move a variation of the freq range match helper to cfg80211.

>>  	if (!curr_ctx || (curr_ctx->replace_state ==
>>  			  IEEE80211_CHANCTX_WILL_BE_REPLACED) ||
>> @@ -1096,6 +1117,12 @@ ieee80211_replace_chanctx(struct ieee80211_local *local,
>>  			if (!list_empty(&ctx->reserved_links))
>>  				continue;
>>  
>> +			if (ctx->conf.radio_idx >= 0) {
>> +					radio = &wiphy->radio[ctx->conf.radio_idx];
>> +					if (!ieee80211_radio_freq_match(radio, chanreq))
>> +							continue;
>> +			}
> 
> something happened to indentation here :)

Will fix :)

>> +static bool
>> +ieee80211_find_available_radio(struct ieee80211_local *local,
>> +			       const struct ieee80211_chan_req *chanreq,
>> +			       int *radio_idx)
>> +{
>> +	struct wiphy *wiphy = local->hw.wiphy;
>> +	const struct wiphy_radio *radio;
>> +	int i;
>> +
>> +	*radio_idx = -1;
>> +	if (!wiphy->n_radio)
>> +		return true;
>> +
>> +	for (i = 0; i < wiphy->n_radio; i++) {
>> +		radio = &wiphy->radio[i];
>> +		if (!ieee80211_radio_freq_match(radio, chanreq))
>> +			continue;
>> +
>> +		if (!ieee80211_can_create_new_chanctx(local, i))
>> +			continue;
>> +
>> +		*radio_idx = i;
>> +		return true;
>> +	}
>> +
>> +	return false;
>> +}
> 
> which would also get used here to find the radio first, though would
> have to differentiate n_radio still, of course.

See above

- Felix