Re: [RFC v2 4/6] mac80211: add utility function for tx_rate - rate_info conversion

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2023-01-19 at 12:31 +0100, Jonas Jelonek wrote:
> > On 12. Jan 2023, at 11:26, Johannes Berg <johannes@sipsolutions.net>
> > wrote:
> > 
> > > +void ieee80211_rate_get_rate_info(const struct ieee80211_tx_rate
> > > *rate,
> > > +						struct wiphy
> > > *wiphy, u8 band,
> > > + 						struct rate_info
> > > *rate_info)
> > > +{
> > > + 	memset(rate_info, 0, sizeof(struct rate_info));
> > > +
> > > + 	if (rate->flags & IEEE80211_TX_RC_MCS) { /* 802.11n */
> > > + 		rate_info->flags |= RATE_INFO_FLAGS_MCS;
> > > + 		rate_info->mcs = rate->idx;
> > > + 	} else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) { /*
> > > 802.11ac */
> > > + 		rate_info->flags |= RATE_INFO_FLAGS_VHT_MCS;
> > > + 		rate_info->mcs =
> > > ieee80211_rate_get_vht_mcs(rate);
> > > + 		rate_info->nss =
> > > ieee80211_rate_get_vht_nss(rate);
> > > + 	} else { /* 802.11a/b/g */
> > 
> > what about HE/EHT?
> 
> ieee80211_tx_rate uses an s8 for rate/MCS index, so only up to VHT
> rates fit in there.
> For rates above VHT, rate_info is needed, thus are are no HE/EHT rates
> occuring in
> ieee80211_tx_rate. Same applies to your comment on the hwsim
> conversion.

I guess I should've read the commit message more closely ;-)

But please add kernel-doc to the function; both in general it'd be good
to have, and in particular explaining that this is more for older
drivers I guess?

johannes