mac80211: minstrel_ht: add basic support for VHT rates <= 3SS@80MHz

When the new CONFIG_MAC80211_RC_MINSTREL_VHT is not set (default 'N'),
there is no behavioral change including in sampling and MCS_GROUP_RATES
remains 8.
Otherwise MCS_GROUP_RATES is 10, and a module parameter *vht_only*
(default 'true'), restricts the rates selection to VHT when VHT is
supported.

Regarding the debugfs stats buffer:
It is explicitly increased from 8k to 32k to fit every rates incl. when
both HT and VHT rates are enabled, as for the format, before:
type           rate     tpt eprob *prob ret  *ok(*cum)        ok(      cum)
HT20/LGI ABCDP MCS0     0.0   0.0   0.0   1    0(   0)         0(        0)
after:
 type           rate      tpt eprob *prob ret  *ok(*cum)        ok(      cum)
 HT20/LGI ABCDP MCS0      0.0   0.0   0.0   1    0(   0)         0(        0)
VHT40/LGI       MCS5/2    0.0   0.0   0.0   0    0(   0)         0(        0)

Signed-off-by: Karl Beldan <karl.beldan@rivierawaves.com>
Cc: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/Kconfig b/net/mac80211/Kconfig
index aeb6a48..67cf812 100644 (file)
--- a/net/mac80211/Kconfig
+++ b/net/mac80211/Kconfig
@@ -33,6 +33,13 @@ config MAC80211_RC_MINSTREL_HT
        ---help---
          This option enables the 'minstrel_ht' TX rate control algorithm
 
+config MAC80211_RC_MINSTREL_VHT
+       bool "Minstrel 802.11ac support" if EXPERT
+       depends on MAC80211_RC_MINSTREL_HT
+       default n
+       ---help---
+         This option enables VHT in the 'minstrel_ht' TX rate control algorithm
+
 choice
        prompt "Default rate control algorithm"
        depends on MAC80211_HAS_RC

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index e760d3d..4666681 100644 (file)
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -10,6 +10,7 @@
 #include <linux/skbuff.h>
 #include <linux/debugfs.h>
 #include <linux/random.h>
+#include <linux/moduleparam.h>
 #include <linux/ieee80211.h>
 #include <net/mac80211.h>
 #include "rate.h"
@@ -36,6 +37,7 @@
 
 #define BW_20                  0
 #define BW_40                  1
+#define BW_80                  2
 
 /*
  * Define group sort order: HT40 -> SGI -> #streams
@@ -66,6 +68,47 @@
        }                                                               \
 }
 
+#define VHT_GROUP_IDX(_streams, _sgi, _bw)                             \
+       (MINSTREL_VHT_GROUP_0 +                                         \
+        MINSTREL_MAX_STREAMS * 2 * (_bw) +                             \
+        MINSTREL_MAX_STREAMS * (_sgi) +                                \
+        (_streams) - 1)
+
+#define BW2VBPS(_bw, r3, r2, r1)                                       \
+       (_bw == BW_80 ? r3 : _bw == BW_40 ? r2 : r1)
+
+#define VHT_GROUP(_streams, _sgi, _bw)                                 \
+       [VHT_GROUP_IDX(_streams, _sgi, _bw)] = {                        \
+       .streams = _streams,                                            \
+       .flags =                                                        \
+               IEEE80211_TX_RC_VHT_MCS |                               \
+               (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) |                 \
+               (_bw == BW_80 ? IEEE80211_TX_RC_80_MHZ_WIDTH :          \
+                _bw == BW_40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0),      \
+       .duration = {                                                   \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw,  117,  54,  26)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw,  234, 108,  52)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw,  351, 162,  78)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw,  468, 216, 104)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw,  702, 324, 156)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw,  936, 432, 208)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw, 1053, 486, 234)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw, 1170, 540, 260)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw, 1404, 648, 312)),             \
+               MCS_DURATION(_streams, _sgi,                            \
+                            BW2VBPS(_bw, 1560, 720, 346))              \
+       }                                                               \
+}
+
 #define CCK_DURATION(_bitrate, _short, _len)           \
        (1000 * (10 /* SIFS */ +                        \
         (_short ? 72 + 24 : 144 + 48) +                \
@@ -91,6 +134,13 @@
                }                                       \
        }
 
+#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
+static bool minstrel_vht_only = true;
+module_param(minstrel_vht_only, bool, 0644);
+MODULE_PARM_DESC(minstrel_vht_only,
+                "Use only VHT rates when VHT is supported by sta.");
+#endif
+
 /*
  * To enable sufficiently targeted rate sampling, MCS rates are divided into
  * groups, based on the number of streams and flags (HT40, SGI) that they
@@ -124,9 +174,46 @@ const struct mcs_group minstrel_mcs_groups[] = {
        MCS_GROUP(3, 1, BW_40),
 #endif
 
-       CCK_GROUP
-};
+       CCK_GROUP,
+
+#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
+       VHT_GROUP(1, 0, BW_20),
+       VHT_GROUP(2, 0, BW_20),
+#if MINSTREL_MAX_STREAMS >= 3
+       VHT_GROUP(3, 0, BW_20),
+#endif
+
+       VHT_GROUP(1, 1, BW_20),
+       VHT_GROUP(2, 1, BW_20),
+#if MINSTREL_MAX_STREAMS >= 3
+       VHT_GROUP(3, 1, BW_20),
+#endif
 
+       VHT_GROUP(1, 0, BW_40),
+       VHT_GROUP(2, 0, BW_40),
+#if MINSTREL_MAX_STREAMS >= 3
+       VHT_GROUP(3, 0, BW_40),
+#endif
+
+       VHT_GROUP(1, 1, BW_40),
+       VHT_GROUP(2, 1, BW_40),
+#if MINSTREL_MAX_STREAMS >= 3
+       VHT_GROUP(3, 1, BW_40),
+#endif
+
+       VHT_GROUP(1, 0, BW_80),
+       VHT_GROUP(2, 0, BW_80),
+#if MINSTREL_MAX_STREAMS >= 3
+       VHT_GROUP(3, 0, BW_80),
+#endif
+
+       VHT_GROUP(1, 1, BW_80),
+       VHT_GROUP(2, 1, BW_80),
+#if MINSTREL_MAX_STREAMS >= 3
+       VHT_GROUP(3, 1, BW_80),
+#endif
+#endif
+};
 
 static u8 sample_table[SAMPLE_COLUMNS][MCS_GROUP_RATES] __read_mostly;
 
@@ -134,6 +221,45 @@ static void
 minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi);
 
 /*
+ * Some VHT MCSes are invalid (when Ndbps / Nes is not an integer)
+ * e.g for MCS9@20MHzx1Nss: Ndbps=8x52*(5/6) Nes=1
+ *
+ * Returns the valid mcs map for struct minstrel_mcs_group_data.supported
+ */
+static u16
+minstrel_get_valid_vht_rates(int bw, int nss, __le16 mcs_map)
+{
+       u16 mask = 0;
+
+       if (bw == BW_20) {
+               if (nss != 3 && nss != 6)
+                       mask = BIT(9);
+       } else if (bw == BW_80) {
+               if (nss == 3 || nss == 7)
+                       mask = BIT(6);
+               else if (nss == 6)
+                       mask = BIT(9);
+       } else {
+               WARN_ON(bw != BW_40);
+       }
+
+       switch ((le16_to_cpu(mcs_map) >> (2 * (nss - 1))) & 3) {
+       case IEEE80211_VHT_MCS_SUPPORT_0_7:
+               mask |= 0x300;
+               break;
+       case IEEE80211_VHT_MCS_SUPPORT_0_8:
+               mask |= 0x200;
+               break;
+       case IEEE80211_VHT_MCS_SUPPORT_0_9:
+               break;
+       default:
+               mask = 0x3ff;
+       }
+
+       return 0x3ff & ~mask;
+}
+
+/*
  * Look up an MCS group index based on mac80211 rate information
  */
 static int
@@ -144,6 +270,15 @@ minstrel_ht_get_group_idx(struct ieee80211_tx_rate *rate)
                         !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH));
 }
 
+static int
+minstrel_vht_get_group_idx(struct ieee80211_tx_rate *rate)
+{
+       return VHT_GROUP_IDX(ieee80211_rate_get_vht_nss(rate),
+                            !!(rate->flags & IEEE80211_TX_RC_SHORT_GI),
+                            !!(rate->flags & IEEE80211_TX_RC_40_MHZ_WIDTH) +
+                            2*!!(rate->flags & IEEE80211_TX_RC_80_MHZ_WIDTH));
+}
+
 static struct minstrel_rate_stats *
 minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
                      struct ieee80211_tx_rate *rate)
@@ -153,6 +288,9 @@ minstrel_ht_get_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
        if (rate->flags & IEEE80211_TX_RC_MCS) {
                group = minstrel_ht_get_group_idx(rate);
                idx = rate->idx % 8;
+       } else if (rate->flags & IEEE80211_TX_RC_VHT_MCS) {
+               group = minstrel_vht_get_group_idx(rate);
+               idx = ieee80211_rate_get_vht_mcs(rate);
        } else {
                group = MINSTREL_CCK_GROUP;
 
@@ -489,7 +627,8 @@ minstrel_ht_txstat_valid(struct minstrel_priv *mp, struct ieee80211_tx_rate *rat
        if (!rate->count)
                return false;
 
-       if (rate->flags & IEEE80211_TX_RC_MCS)
+       if (rate->flags & IEEE80211_TX_RC_MCS ||
+           rate->flags & IEEE80211_TX_RC_VHT_MCS)
                return true;
 
        return rate->idx == mp->cck_rates[0] ||
@@ -736,6 +875,9 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
 
        if (index / MCS_GROUP_RATES == MINSTREL_CCK_GROUP)
                idx = mp->cck_rates[index % ARRAY_SIZE(mp->cck_rates)];
+       else if (flags & IEEE80211_TX_RC_VHT_MCS)
+               idx = ((group->streams - 1) << 4) |
+                     ((index % MCS_GROUP_RATES) & 0xF);
        else
                idx = index % MCS_GROUP_RATES + (group->streams - 1) * 8;
 
@@ -917,6 +1059,9 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta,
        if (sample_idx / MCS_GROUP_RATES == MINSTREL_CCK_GROUP) {
                int idx = sample_idx % ARRAY_SIZE(mp->cck_rates);
                rate->idx = mp->cck_rates[idx];
+       } else if (sample_group->flags & IEEE80211_TX_RC_VHT_MCS) {
+               ieee80211_rate_set_vht(rate, sample_idx % MCS_GROUP_RATES,
+                                      sample_group->streams);
        } else {
                rate->idx = sample_idx % MCS_GROUP_RATES +
                            (sample_group->streams - 1) * 8;
@@ -962,6 +1107,8 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
        struct minstrel_ht_sta *mi = &msp->ht;
        struct ieee80211_mcs_info *mcs = &sta->ht_cap.mcs;
        u16 sta_cap = sta->ht_cap.cap;
+       struct ieee80211_sta_vht_cap *vht_cap = &sta->vht_cap;
+       int use_vht;
        int n_supported = 0;
        int ack_dur;
        int stbc;
@@ -973,6 +1120,13 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
 
        BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups) != MINSTREL_GROUPS_NB);
 
+#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
+       if (vht_cap->vht_supported)
+               use_vht = vht_cap->vht_mcs.tx_mcs_map != cpu_to_le16(~0);
+       else
+#endif
+       use_vht = 0;
+
        msp->is_ht = true;
        memset(mi, 0, sizeof(*mi));
 
@@ -996,15 +1150,19 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
        }
        mi->sample_tries = 4;
 
-       stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
-               IEEE80211_HT_CAP_RX_STBC_SHIFT;
-       mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
+       /* TODO tx_flags for vht - ATM the RC API is not fine-grained enough */
+       if (!use_vht) {
+               stbc = (sta_cap & IEEE80211_HT_CAP_RX_STBC) >>
+                       IEEE80211_HT_CAP_RX_STBC_SHIFT;
+               mi->tx_flags |= stbc << IEEE80211_TX_CTL_STBC_SHIFT;
 
-       if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
-               mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
+               if (sta_cap & IEEE80211_HT_CAP_LDPC_CODING)
+                       mi->tx_flags |= IEEE80211_TX_CTL_LDPC;
+       }
 
        for (i = 0; i < ARRAY_SIZE(mi->groups); i++) {
                u32 gflags = minstrel_mcs_groups[i].flags;
+               int bw, nss;
 
                mi->groups[i].supported = 0;
                if (i == MINSTREL_CCK_GROUP) {
@@ -1026,13 +1184,47 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband,
                    sta->bandwidth < IEEE80211_STA_RX_BW_40)
                        continue;
 
+               nss = minstrel_mcs_groups[i].streams;
+
                /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
-               if (sta->smps_mode == IEEE80211_SMPS_STATIC &&
-                   minstrel_mcs_groups[i].streams > 1)
+               if (sta->smps_mode == IEEE80211_SMPS_STATIC && nss > 1)
+                       continue;
+
+               /* HT rate */
+               if (gflags & IEEE80211_TX_RC_MCS) {
+#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
+                       if (minstrel_vht_only)
+                               continue;
+#endif
+                       mi->groups[i].supported = mcs->rx_mask[nss - 1];
+                       if (mi->groups[i].supported)
+                               n_supported++;
+                       continue;
+               }
+
+               /* VHT rate */
+               if (!vht_cap->vht_supported ||
+                   WARN_ON(!(gflags & IEEE80211_TX_RC_VHT_MCS)) ||
+                   WARN_ON(gflags & IEEE80211_TX_RC_160_MHZ_WIDTH))
                        continue;
 
-               mi->groups[i].supported =
-                       mcs->rx_mask[minstrel_mcs_groups[i].streams - 1];
+               if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH) {
+                       if (sta->bandwidth < IEEE80211_STA_RX_BW_80 ||
+                           ((gflags & IEEE80211_TX_RC_SHORT_GI) &&
+                            !(vht_cap->cap & IEEE80211_VHT_CAP_SHORT_GI_80))) {
+                               continue;
+                       }
+               }
+
+               if (gflags & IEEE80211_TX_RC_40_MHZ_WIDTH)
+                       bw = BW_40;
+               else if (gflags & IEEE80211_TX_RC_80_MHZ_WIDTH)
+                       bw = BW_80;
+               else
+                       bw = BW_20;
+
+               mi->groups[i].supported = minstrel_get_valid_vht_rates(bw, nss,
+                               vht_cap->vht_mcs.tx_mcs_map);
 
                if (mi->groups[i].supported)
                        n_supported++;

diff --git a/net/mac80211/rc80211_minstrel_ht.h b/net/mac80211/rc80211_minstrel_ht.h
index e747ac6..f2217d6 100644 (file)
--- a/net/mac80211/rc80211_minstrel_ht.h
+++ b/net/mac80211/rc80211_minstrel_ht.h
@@ -15,17 +15,30 @@
  */
 #define MINSTREL_MAX_STREAMS           3
 #define MINSTREL_HT_STREAM_GROUPS      4 /* BW(=2) * SGI(=2) */
+#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
+#define MINSTREL_VHT_STREAM_GROUPS     6 /* BW(=3) * SGI(=2) */
+#else
+#define MINSTREL_VHT_STREAM_GROUPS     0
+#endif
 
 #define MINSTREL_HT_GROUPS_NB  (MINSTREL_MAX_STREAMS *         \
                                 MINSTREL_HT_STREAM_GROUPS)
+#define MINSTREL_VHT_GROUPS_NB (MINSTREL_MAX_STREAMS *         \
+                                MINSTREL_VHT_STREAM_GROUPS)
 #define MINSTREL_CCK_GROUPS_NB 1
 #define MINSTREL_GROUPS_NB     (MINSTREL_HT_GROUPS_NB +        \
+                                MINSTREL_VHT_GROUPS_NB +       \
                                 MINSTREL_CCK_GROUPS_NB)
 
 #define MINSTREL_HT_GROUP_0    0
 #define MINSTREL_CCK_GROUP     (MINSTREL_HT_GROUP_0 + MINSTREL_HT_GROUPS_NB)
+#define MINSTREL_VHT_GROUP_0   (MINSTREL_CCK_GROUP + 1)
 
-#define MCS_GROUP_RATES        8
+#ifdef CONFIG_MAC80211_RC_MINSTREL_VHT
+#define MCS_GROUP_RATES                10
+#else
+#define MCS_GROUP_RATES                8
+#endif
 
 struct mcs_group {
        u32 flags;
@@ -40,7 +53,7 @@ struct minstrel_mcs_group_data {
        u8 column;
 
        /* bitfield of supported MCS rates of this group */
-       u8 supported;
+       u16 supported;
 
        /* sorted rate set within a MCS group*/
        u16 max_group_tp_rate[MAX_THR_RATES];

diff --git a/net/mac80211/rc80211_minstrel_ht_debugfs.c b/net/mac80211/rc80211_minstrel_ht_debugfs.c
index d2f53b8..52bb6ef 100644 (file)
--- a/net/mac80211/rc80211_minstrel_ht_debugfs.c
+++ b/net/mac80211/rc80211_minstrel_ht_debugfs.c
@@ -29,6 +29,8 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
        mg = &minstrel_mcs_groups[i];
        if (mg->flags & IEEE80211_TX_RC_40_MHZ_WIDTH)
                htmode = '4';
+       else if (mg->flags & IEEE80211_TX_RC_80_MHZ_WIDTH)
+               htmode = '8';
        if (mg->flags & IEEE80211_TX_RC_SHORT_GI)
                gimode = 'S';
 
@@ -41,9 +43,11 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
                        continue;
 
                if (i == MINSTREL_CCK_GROUP)
-                       p += sprintf(p, "CCK/%cP   ", j < 4 ? 'L' : 'S');
+                       p += sprintf(p, " CCK/%cP   ", j < 4 ? 'L' : 'S');
+               else if (i >= MINSTREL_VHT_GROUP_0)
+                       p += sprintf(p, "VHT%c0/%cGI ", htmode, gimode);
                else
-                       p += sprintf(p, "HT%c0/%cGI ", htmode, gimode);
+                       p += sprintf(p, " HT%c0/%cGI ", htmode, gimode);
 
                *(p++) = (idx == mi->max_tp_rate[0]) ? 'A' : ' ';
                *(p++) = (idx == mi->max_tp_rate[1]) ? 'B' : ' ';
@@ -53,9 +57,11 @@ minstrel_ht_stats_dump(struct minstrel_ht_sta *mi, int i, char *p)
 
                if (i == MINSTREL_CCK_GROUP) {
                        int r = bitrates[j % 4];
-                       p += sprintf(p, " %2u.%1uM", r / 10, r % 10);
+                       p += sprintf(p, " %2u.%1uM ", r / 10, r % 10);
+               } else if (i >= MINSTREL_VHT_GROUP_0) {
+                       p += sprintf(p, " MCS%-1u/%1u", j, mg->streams);
                } else {
-                       p += sprintf(p, " MCS%-2u", (mg->streams - 1) * 8 + j);
+                       p += sprintf(p, " MCS%-2u ", (mg->streams - 1) * 8 + j);
                }
 
                tp = mr->cur_tp / 10;
@@ -94,19 +100,20 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file)
                return ret;
        }
 
-       ms = kmalloc(8192, GFP_KERNEL);
+       ms = kmalloc(32768, GFP_KERNEL);
        if (!ms)
                return -ENOMEM;
 
        file->private_data = ms;
        p = ms->buf;
-       p += sprintf(p, "type           rate     tpt eprob *prob "
+       p += sprintf(p, " type           rate      tpt eprob *prob "
                        "ret  *ok(*cum)        ok(      cum)\n");
 
-
        p = minstrel_ht_stats_dump(mi, MINSTREL_CCK_GROUP, p);
        for (i = 0; i < MINSTREL_CCK_GROUP; i++)
                p = minstrel_ht_stats_dump(mi, i, p);
+       for (i++; i < ARRAY_SIZE(mi->groups); i++)
+               p = minstrel_ht_stats_dump(mi, i, p);
 
        p += sprintf(p, "\nTotal packet count::    ideal %d      "
                        "lookaround %d\n",
@@ -117,7 +124,7 @@ minstrel_ht_stats_open(struct inode *inode, struct file *file)
                MINSTREL_TRUNC(mi->avg_ampdu_len * 10) % 10);
        ms->len = p - ms->buf;
 
-       WARN_ON(ms->len + sizeof(*ms) > 8192);
+       WARN_ON(ms->len + sizeof(*ms) > 32768);
 
        return nonseekable_open(inode, file);
 }