On Tue Nov 19, 2024 at 5:27 AM CET, Aditya Kumar Singh wrote:
> From: Sathishkumar Muruganandam <quic_murugana@xxxxxxxxxxx>
>
> Currently, ieee80211_ie_build_he_oper() lacks support for 320 MHz handling
> (already noted as a TODO). This is because 320 MHz is not included in
> IEEE 802.11-ax. However, IEEE 802.11-be introduces 320 MHz support and if
> the chandef indicates a 320 MHz bandwidth and is used directly as it is, it
> will result in an incorrect HE Operation Information Element.
>
> In order to support EHT 320 MHz, HE Operation Element should indicate
> bandwidth as 160 MHz only. In EHT Operation IE, the correct bandwidth will
> be present. Devices capable of EHT can parse EHT Information Element and
> connect in 320 MHz and other HE capable devices can parse HE and can
> connect in 160 MHz.
>
> Add support to downgrade the bandwidth in ieee80211_ie_build_he_oper()
> during 320 MHz operation and advertise it.
>
> Signed-off-by: Sathishkumar Muruganandam <quic_murugana@xxxxxxxxxxx>
> Signed-off-by: Aditya Kumar Singh <quic_adisi@xxxxxxxxxxx>
> ---
> net/mac80211/util.c | 29 ++++++++++++++++++-----------
> 1 file changed, 18 insertions(+), 11 deletions(-)
>
> diff --git a/net/mac80211/util.c b/net/mac80211/util.c
> index a4e1301cc999d24d6ab1bd899742a2ff04229040..c88ce537aaa7ea5d59dc42e5f30805c6eb4a5c6d 100644
> --- a/net/mac80211/util.c
> +++ b/net/mac80211/util.c
> @@ -2762,6 +2762,7 @@ u8 *ieee80211_ie_build_he_oper(u8 *pos, const struct cfg80211_chan_def *chandef)
> {
> struct ieee80211_he_operation *he_oper;
> struct ieee80211_he_6ghz_oper *he_6ghz_op;
> + struct cfg80211_chan_def he_chandef;
> u32 he_oper_params;
> u8 ie_len = 1 + sizeof(struct ieee80211_he_operation);
>
> @@ -2793,27 +2794,33 @@ u8 *ieee80211_ie_build_he_oper(u8 *pos, const struct cfg80211_chan_def *chandef)
> if (chandef->chan->band != NL80211_BAND_6GHZ)
> goto out;
>
> + cfg80211_chandef_create(&he_chandef, chandef->chan, NL80211_CHAN_NO_HT);
> + he_chandef.center_freq1 = chandef->center_freq1;
> + he_chandef.center_freq2 = chandef->center_freq2;
> + he_chandef.width = chandef->width;
> +
> /* TODO add VHT operational */
> he_6ghz_op = (struct ieee80211_he_6ghz_oper *)pos;
> he_6ghz_op->minrate = 6; /* 6 Mbps */
> he_6ghz_op->primary =
> - ieee80211_frequency_to_channel(chandef->chan->center_freq);
> + ieee80211_frequency_to_channel(he_chandef.chan->center_freq);
> he_6ghz_op->ccfs0 =
> - ieee80211_frequency_to_channel(chandef->center_freq1);
> - if (chandef->center_freq2)
> + ieee80211_frequency_to_channel(he_chandef.center_freq1);
> + if (he_chandef.center_freq2)
> he_6ghz_op->ccfs1 =
> - ieee80211_frequency_to_channel(chandef->center_freq2);
> + ieee80211_frequency_to_channel(he_chandef.center_freq2);
> else
> he_6ghz_op->ccfs1 = 0;
>
> - switch (chandef->width) {
> + switch (he_chandef.width) {
> case NL80211_CHAN_WIDTH_320:
> - /*
> - * TODO: mesh operation is not defined over 6GHz 320 MHz
> - * channels.
> + /* Downgrade EHT 320 MHz BW to 160 MHz for HE and set new
> + * center_freq1
> */
> - WARN_ON(1);
> - break;
> + ieee80211_chandef_downgrade(&he_chandef, NULL);
> + he_6ghz_op->ccfs0 =
> + ieee80211_frequency_to_channel(he_chandef.center_freq1);
I don't understand the full implication of those two calls but I made 320MHz
work by doing the same as for 160 but with +/- = 16 instead of 8.
> + fallthrough;
> case NL80211_CHAN_WIDTH_160:
> /* Convert 160 MHz channel width to new style as interop
> * workaround.
> @@ -2821,7 +2828,7 @@ u8 *ieee80211_ie_build_he_oper(u8 *pos, const struct cfg80211_chan_def *chandef)
> he_6ghz_op->control =
> IEEE80211_HE_6GHZ_OPER_CTRL_CHANWIDTH_160MHZ;
> he_6ghz_op->ccfs1 = he_6ghz_op->ccfs0;
> - if (chandef->chan->center_freq < chandef->center_freq1)
> + if (he_chandef.chan->center_freq < he_chandef.center_freq1)
> he_6ghz_op->ccfs0 -= 8;
> else
> he_6ghz_op->ccfs0 += 8;
Something along this lines seemed to be enough:
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index a4e1301cc999..f24479f74813 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2808,18 +2808,15 @@ u8 *ieee80211_ie_build_he_oper(u8 *pos, const struct cfg80211_chan_def *chandef)
switch (chandef->width) {
case NL80211_CHAN_WIDTH_320:
- /*
- * TODO: mesh operation is not defined over 6GHz 320 MHz
- * channels.
- */
- WARN_ON(1);
- break;
+ if (chandef->chan->center_freq < chandef->center_freq1)
+ he_6ghz_op->ccfs0 -= 16;
+ else
+ he_6ghz_op->ccfs0 += 16;
+ fallthrough;
case NL80211_CHAN_WIDTH_160:
/* Convert 160 MHz channel width to new style as interop
* workaround.
*/
- he_6ghz_op->control =
- IEEE80211_HE_6GHZ_OPER_CTRL_CHANWIDTH_160MHZ;
he_6ghz_op->ccfs1 = he_6ghz_op->ccfs0;
if (chandef->chan->center_freq < chandef->center_freq1)
he_6ghz_op->ccfs0 -= 8;
--
2.47.0
