On 14-2-2017 14:22, Johannes Berg wrote:
> From: Johannes Berg <johannes.berg@xxxxxxxxx>
>
> IEEE 802.11-2016 extended the VHT capability fields to allow
> indicating the number of spatial streams depending on the
> actually used bandwidth, add support for decoding this.
>
> Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
> ---
> include/linux/ieee80211.h | 105 +++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 103 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
> index 4a7200c6c9ea..c51d309a45e7 100644
> --- a/include/linux/ieee80211.h
> +++ b/include/linux/ieee80211.h
> @@ -1457,13 +1457,16 @@ struct ieee80211_ht_operation {
> * STA can receive. Rate expressed in units of 1 Mbps.
> * If this field is 0 this value should not be used to
> * consider the highest RX data rate supported.
> - * The top 3 bits of this field are reserved.
> + * The top 3 bits of this field indicate the Maximum NSTS,total
> + * (a beamformee capability.)
> * @tx_mcs_map: TX MCS map 2 bits for each stream, total 8 streams
> * @tx_highest: Indicates highest long GI VHT PPDU data rate
> * STA can transmit. Rate expressed in units of 1 Mbps.
> * If this field is 0 this value should not be used to
> * consider the highest TX data rate supported.
> - * The top 3 bits of this field are reserved.
> + * The top 2 bits of this field are reserved, the
> + * 3rd bit from the top indiciates VHT Extended NSS BW
> + * Capability.
> */
> struct ieee80211_vht_mcs_info {
> __le16 rx_mcs_map;
> @@ -1472,6 +1475,13 @@ struct ieee80211_vht_mcs_info {
> __le16 tx_highest;
> } __packed;
>
> +/* for rx_highest */
> +#define IEEE80211_VHT_MAX_NSTS_TOTAL_SHIFT 13
> +#define IEEE80211_VHT_MAX_NSTS_TOTAL_MASK (7 << IEEE80211_VHT_MAX_NSTS_TOTAL_SHIFT)
> +
> +/* for tx_highest */
> +#define IEEE80211_VHT_EXT_NSS_BW_CAPABLE (1 << 13)
> +
> /**
> * enum ieee80211_vht_mcs_support - VHT MCS support definitions
> * @IEEE80211_VHT_MCS_SUPPORT_0_7: MCSes 0-7 are supported for the
> @@ -1547,6 +1557,7 @@ struct ieee80211_vht_operation {
> #define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ 0x00000004
> #define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ 0x00000008
> #define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK 0x0000000C
> +#define IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_SHIFT 2
> #define IEEE80211_VHT_CAP_RXLDPC 0x00000010
> #define IEEE80211_VHT_CAP_SHORT_GI_80 0x00000020
> #define IEEE80211_VHT_CAP_SHORT_GI_160 0x00000040
> @@ -1575,6 +1586,96 @@ struct ieee80211_vht_operation {
> #define IEEE80211_VHT_CAP_VHT_LINK_ADAPTATION_VHT_MRQ_MFB 0x0c000000
> #define IEEE80211_VHT_CAP_RX_ANTENNA_PATTERN 0x10000000
> #define IEEE80211_VHT_CAP_TX_ANTENNA_PATTERN 0x20000000
> +#define IEEE80211_VHT_CAP_EXT_NSS_BW_SHIFT 30
> +#define IEEE80211_VHT_CAP_EXT_NSS_BW_MASK 0xc0000000
> +
> +static int __maybe_unused
> +ieee80211_get_vht_max_nss(struct ieee80211_vht_cap *cap,
> + enum ieee80211_vht_chanwidth bw,
> + int mcs)
> +{
> + u16 map = le16_to_cpu(cap->supp_mcs.rx_mcs_map);
> + int max_vht_nss;
> + int ext_nss_bw;
> + int supp_width;
> + int i, mcs_encoding;
> +
> + if (map == 0xffff)
> + return 0;
> +
> + if (WARN_ON(mcs > 9))
> + return 0;
> + if (mcs <= 7)
> + mcs_encoding = 0;
> + else if (mcs == 8)
> + mcs_encoding = 1;
> + else
> + mcs_encoding = 2;
> +
> + /* find max_vht_nss for the given MCS */
> + for (i = 7; i >= 0; i--) {
> + int supp = (map >> (2*i)) & 3;
> +
> + if (supp == 3)
> + continue;
> +
> + if (supp >= mcs_encoding) {
> + max_vht_nss = i;
> + break;
> + }
> + }
> +
> + if (!(cap->supp_mcs.tx_mcs_map & cpu_to_le16(IEEE80211_VHT_EXT_NSS_BW_CAPABLE)))
> + return max_vht_nss;
> +
> + ext_nss_bw = (le32_to_cpu(cap->vht_cap_info) &
> + IEEE80211_VHT_CAP_EXT_NSS_BW_MASK)
> + >> IEEE80211_VHT_CAP_EXT_NSS_BW_SHIFT;
> + supp_width = (le32_to_cpu(cap->vht_cap_info) &
> + IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK)
> + >> IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_SHIFT;
> +
> + /*
> + * Cover all the special cases according to IEEE 802.11-2016 Table 9-250.
> + * All other cases are either factor of 1 or not valid/supported.
> + */
> + switch (bw) {
> + case IEEE80211_VHT_CHANWIDTH_USE_HT:
> + case IEEE80211_VHT_CHANWIDTH_80MHZ:
> + if ((supp_width == 1 || supp_width == 2) &&
> + ext_nss_bw == 3)
> + return 2 * max_vht_nss;
> + break;
> + case IEEE80211_VHT_CHANWIDTH_160MHZ:
> + if (supp_width == 0 &&
> + (ext_nss_bw == 1 || ext_nss_bw == 2))
> + return DIV_ROUND_UP(max_vht_nss, 2);
> + if (supp_width == 0 &&
> + ext_nss_bw == 3)
> + return DIV_ROUND_UP(3 * max_vht_nss, 4);
> + if (supp_width == 1 &&
> + ext_nss_bw == 3)
> + return 2 * max_vht_nss;
> + break;
> + case IEEE80211_VHT_CHANWIDTH_80P80MHZ:
> + if (supp_width == 0 &&
> + ext_nss_bw == 2)
> + return DIV_ROUND_UP(max_vht_nss, 2);
> + if (supp_width == 0 &&
> + ext_nss_bw == 3)
> + return DIV_ROUND_UP(3 * max_vht_nss, 4);
> + if (supp_width == 1 &&
> + ext_nss_bw == 1)
> + return DIV_ROUND_UP(max_vht_nss, 2);
> + if (supp_width == 1 &&
> + ext_nss_bw == 2)
> + return DIV_ROUND_UP(3 * max_vht_nss, 4);
> + break;
> + }
Looks good to me.
> + /* not covered or invalid combination received */
Do you want to inform about the invalid/reserved combination.
Regards,
Arend
> + return max_vht_nss;
> +}
>
> /* Authentication algorithms */
> #define WLAN_AUTH_OPEN 0
>
