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Message-ID: <f364ace23f73e90f9cf62b5c8238e78599b6b7ab.camel@sipsolutions.net>
Subject: Re: [RFC v2 4/6] mac80211: add utility function for tx_rate -
 rate_info conversion
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Jonas Jelonek <jelonek.jonas@gmail.com>
Cc:     linux-wireless@vger.kernel.org, Felix Fietkau <nbd@nbd.name>
Date:   Thu, 19 Jan 2023 12:35:18 +0100
In-Reply-To: <9AE44A41-6357-4F3A-BF75-8E3B0A381E9B@gmail.com>
References: <20220920104032.496697-1-jelonek.jonas@gmail.com>
         <20220920104032.496697-5-jelonek.jonas@gmail.com>
         <64731257b957f50b0f66e4d2fcd8c24dea8d70ff.camel@sipsolutions.net>
         <9AE44A41-6357-4F3A-BF75-8E3B0A381E9B@gmail.com>
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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:
> >=20
> > > +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 |=3D RATE_INFO_FLAGS_MCS;
> > > + 		rate_info->mcs =3D rate->idx;
> > > + 	} else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) { /*
> > > 802.11ac */
> > > + 		rate_info->flags |=3D RATE_INFO_FLAGS_VHT_MCS;
> > > + 		rate_info->mcs =3D
> > > ieee80211_rate_get_vht_mcs(rate);
> > > + 		rate_info->nss =3D
> > > ieee80211_rate_get_vht_nss(rate);
> > > + 	} else { /* 802.11a/b/g */
> >=20
> > what about HE/EHT?
>=20
> 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