iwlwifi: adding MIMO3 support in rate scaling

Separated the MIMO tpt matrix into MIMO2 and MIMO3, adding MIMO3 support
in rate scaling algorithm. If the device support 3x3, then utilize all
three antenna (A/B/C) for tx to improve throughput.

Adding rs_switch_to_mimo3() function to allow switch to mimo3 modulation
mode from other modes(legacy/siso/mimo2). Adding rs_move_mimo3_to_other()
function to allow switch from mimo3 modulation mode to either siso or mimo2;
also support toggle between SGI and NGI.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-rs.c

@@ -191,7 +191,7 @@ static void rs_dbgfs_set_mcs(struct iwl_lq_sta *lq_sta,
  * 1, 2, 5.5, 11, 6, 9, 12, 18, 24, 36, 48, 54, 60 MBits
  * "G" is the only table that supports CCK (the first 4 rates).
  */
-/*FIXME:RS:need to separate tables for MIMO2/MIMO3*/
+
 static s32 expected_tpt_A[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 40, 57, 72, 98, 121, 154, 177, 186, 186
 };
@@ -208,11 +208,11 @@ static s32 expected_tpt_siso20MHzSGI[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 46, 46, 82, 110, 132, 168, 192, 202, 211
 };
 
-static s32 expected_tpt_mimo20MHz[IWL_RATE_COUNT] = {
+static s32 expected_tpt_mimo2_20MHz[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 74, 74, 123, 155, 179, 214, 236, 244, 251
 };
 
-static s32 expected_tpt_mimo20MHzSGI[IWL_RATE_COUNT] = {
+static s32 expected_tpt_mimo2_20MHzSGI[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 81, 81, 131, 164, 188, 222, 243, 251, 257
 };
 
@@ -224,14 +224,31 @@ static s32 expected_tpt_siso40MHzSGI[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 83, 83, 135, 169, 193, 229, 250, 257, 264
 };
 
-static s32 expected_tpt_mimo40MHz[IWL_RATE_COUNT] = {
+static s32 expected_tpt_mimo2_40MHz[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 123, 123, 182, 214, 235, 264, 279, 285, 289
 };
 
-static s32 expected_tpt_mimo40MHzSGI[IWL_RATE_COUNT] = {
+static s32 expected_tpt_mimo2_40MHzSGI[IWL_RATE_COUNT] = {
 	0, 0, 0, 0, 131, 131, 191, 222, 242, 270, 284, 289, 293
 };
 
+/* Expected throughput metric MIMO3 */
+static s32 expected_tpt_mimo3_20MHz[IWL_RATE_COUNT] = {
+	0, 0, 0, 0, 99, 99, 153, 186, 208, 239, 256, 263, 268
+};
+
+static s32 expected_tpt_mimo3_20MHzSGI[IWL_RATE_COUNT] = {
+	0, 0, 0, 0, 106, 106, 162, 194, 215, 246, 262, 268, 273
+};
+
+static s32 expected_tpt_mimo3_40MHz[IWL_RATE_COUNT] = {
+	0, 0, 0, 0, 152, 152, 211, 239, 255, 279, 290, 294, 297
+};
+
+static s32 expected_tpt_mimo3_40MHzSGI[IWL_RATE_COUNT] = {
+	0, 0, 0, 0, 160, 160, 219, 245, 261, 284, 294, 297, 300
+};
+
 static inline u8 rs_extract_rate(u32 rate_n_flags)
 {
 	return (u8)(rate_n_flags & 0xFF);
@@ -1011,17 +1028,26 @@ static void rs_set_expected_tpt_table(struct iwl_lq_sta *lq_sta,
 			tbl->expected_tpt = expected_tpt_siso20MHzSGI;
 		else
 			tbl->expected_tpt = expected_tpt_siso20MHz;
-
-	} else if (is_mimo(tbl->lq_type)) { /* FIXME:need to separate mimo2/3 */
+	} else if (is_mimo2(tbl->lq_type)) {
+		if (tbl->is_fat && !lq_sta->is_dup)
+			if (tbl->is_SGI)
+				tbl->expected_tpt = expected_tpt_mimo2_40MHzSGI;
+			else
+				tbl->expected_tpt = expected_tpt_mimo2_40MHz;
+		else if (tbl->is_SGI)
+			tbl->expected_tpt = expected_tpt_mimo2_20MHzSGI;
+		else
+			tbl->expected_tpt = expected_tpt_mimo2_20MHz;
+	} else if (is_mimo3(tbl->lq_type)) {
 		if (tbl->is_fat && !lq_sta->is_dup)
 			if (tbl->is_SGI)
-				tbl->expected_tpt = expected_tpt_mimo40MHzSGI;
+				tbl->expected_tpt = expected_tpt_mimo3_40MHzSGI;
 			else
-				tbl->expected_tpt = expected_tpt_mimo40MHz;
+				tbl->expected_tpt = expected_tpt_mimo3_40MHz;
 		else if (tbl->is_SGI)
-			tbl->expected_tpt = expected_tpt_mimo20MHzSGI;
+			tbl->expected_tpt = expected_tpt_mimo3_20MHzSGI;
 		else
-			tbl->expected_tpt = expected_tpt_mimo20MHz;
+			tbl->expected_tpt = expected_tpt_mimo3_20MHz;
 	} else
 		tbl->expected_tpt = expected_tpt_G;
 }
@@ -1130,7 +1156,7 @@ static s32 rs_get_best_rate(struct iwl_priv *priv,
 }
 
 /*
- * Set up search table for MIMO
+ * Set up search table for MIMO2
  */
 static int rs_switch_to_mimo2(struct iwl_priv *priv,
 			     struct iwl_lq_sta *lq_sta,
@@ -1183,7 +1209,73 @@ static int rs_switch_to_mimo2(struct iwl_priv *priv,
 	rate = rs_get_best_rate(priv, lq_sta, tbl, rate_mask, index);
 
 	IWL_DEBUG_RATE(priv, "LQ: MIMO2 best rate %d mask %X\n", rate, rate_mask);
+	if ((rate == IWL_RATE_INVALID) || !((1 << rate) & rate_mask)) {
+		IWL_DEBUG_RATE(priv, "Can't switch with index %d rate mask %x\n",
+						rate, rate_mask);
+		return -1;
+	}
+	tbl->current_rate = rate_n_flags_from_tbl(priv, tbl, rate, is_green);
+
+	IWL_DEBUG_RATE(priv, "LQ: Switch to new mcs %X index is green %X\n",
+		     tbl->current_rate, is_green);
+	return 0;
+}
+
+/*
+ * Set up search table for MIMO3
+ */
+static int rs_switch_to_mimo3(struct iwl_priv *priv,
+			     struct iwl_lq_sta *lq_sta,
+			     struct ieee80211_conf *conf,
+			     struct ieee80211_sta *sta,
+			     struct iwl_scale_tbl_info *tbl, int index)
+{
+	u16 rate_mask;
+	s32 rate;
+	s8 is_green = lq_sta->is_green;
+
+	if (!conf_is_ht(conf) || !sta->ht_cap.ht_supported)
+		return -1;
+
+	if (((sta->ht_cap.cap & IEEE80211_HT_CAP_SM_PS) >> 2)
+						== WLAN_HT_CAP_SM_PS_STATIC)
+		return -1;
+
+	/* Need both Tx chains/antennas to support MIMO */
+	if (priv->hw_params.tx_chains_num < 3)
+		return -1;
+
+	IWL_DEBUG_RATE(priv, "LQ: try to switch to MIMO3\n");
+
+	tbl->lq_type = LQ_MIMO3;
+	tbl->is_dup = lq_sta->is_dup;
+	tbl->action = 0;
+	rate_mask = lq_sta->active_mimo3_rate;
+
+	if (priv->current_ht_config.supported_chan_width
+					== IWL_CHANNEL_WIDTH_40MHZ)
+		tbl->is_fat = 1;
+	else
+		tbl->is_fat = 0;
 
+	/* FIXME: - don't toggle SGI here
+	if (tbl->is_fat) {
+		if (priv->current_ht_config.sgf & HT_SHORT_GI_40MHZ_ONLY)
+			tbl->is_SGI = 1;
+		else
+			tbl->is_SGI = 0;
+	} else if (priv->current_ht_config.sgf & HT_SHORT_GI_20MHZ_ONLY)
+		tbl->is_SGI = 1;
+	else
+		tbl->is_SGI = 0;
+	*/
+
+	rs_set_expected_tpt_table(lq_sta, tbl);
+
+	rate = rs_get_best_rate(priv, lq_sta, tbl, rate_mask, index);
+
+	IWL_DEBUG_RATE(priv, "LQ: MIMO3 best rate %d mask %X\n",
+		rate, rate_mask);
 	if ((rate == IWL_RATE_INVALID) || !((1 << rate) & rate_mask)) {
 		IWL_DEBUG_RATE(priv, "Can't switch with index %d rate mask %x\n",
 						rate, rate_mask);
@@ -1342,9 +1434,29 @@ static int rs_move_legacy_other(struct iwl_priv *priv,
 				goto out;
 			}
 			break;
+
+		case IWL_LEGACY_SWITCH_MIMO3_ABC:
+			IWL_DEBUG_RATE(priv, "LQ: Legacy switch to MIMO3\n");
+
+			/* Set up search table to try MIMO3 */
+			memcpy(search_tbl, tbl, sz);
+			search_tbl->is_SGI = 0;
+
+			search_tbl->ant_type = ANT_ABC;
+
+			if (!rs_is_valid_ant(valid_tx_ant, search_tbl->ant_type))
+				break;
+
+			ret = rs_switch_to_mimo3(priv, lq_sta, conf, sta,
+						 search_tbl, index);
+			if (!ret) {
+				lq_sta->action_counter = 0;
+				goto out;
+			}
+			break;
 		}
 		tbl->action++;
-		if (tbl->action > IWL_LEGACY_SWITCH_MIMO2_BC)
+		if (tbl->action > IWL_LEGACY_SWITCH_MIMO3_ABC)
 			tbl->action = IWL_LEGACY_SWITCH_ANTENNA1;
 
 		if (tbl->action == start_action)
@@ -1357,7 +1469,7 @@ static int rs_move_legacy_other(struct iwl_priv *priv,
 out:
 	lq_sta->search_better_tbl = 1;
 	tbl->action++;
-	if (tbl->action > IWL_LEGACY_SWITCH_MIMO2_BC)
+	if (tbl->action > IWL_LEGACY_SWITCH_MIMO3_ABC)
 		tbl->action = IWL_LEGACY_SWITCH_ANTENNA1;
 	return 0;
 
@@ -1457,9 +1569,23 @@ static int rs_move_siso_to_other(struct iwl_priv *priv,
 				rate_n_flags_from_tbl(priv, search_tbl,
 						      index, is_green);
 			goto out;
+		case IWL_SISO_SWITCH_MIMO3_ABC:
+			IWL_DEBUG_RATE(priv, "LQ: SISO switch to MIMO3\n");
+			memcpy(search_tbl, tbl, sz);
+			search_tbl->is_SGI = 0;
+			search_tbl->ant_type = ANT_ABC;
+
+			if (!rs_is_valid_ant(valid_tx_ant, search_tbl->ant_type))
+				break;
+
+			ret = rs_switch_to_mimo3(priv, lq_sta, conf, sta,
+						 search_tbl, index);
+			if (!ret)
+				goto out;
+			break;
 		}
 		tbl->action++;
-		if (tbl->action > IWL_SISO_SWITCH_GI)
+		if (tbl->action > IWL_LEGACY_SWITCH_MIMO3_ABC)
 			tbl->action = IWL_SISO_SWITCH_ANTENNA1;
 
 		if (tbl->action == start_action)
@@ -1471,15 +1597,15 @@ static int rs_move_siso_to_other(struct iwl_priv *priv,
  out:
 	lq_sta->search_better_tbl = 1;
 	tbl->action++;
-	if (tbl->action > IWL_SISO_SWITCH_GI)
+	if (tbl->action > IWL_SISO_SWITCH_MIMO3_ABC)
 		tbl->action = IWL_SISO_SWITCH_ANTENNA1;
 	return 0;
 }
 
 /*
- * Try to switch to new modulation mode from MIMO
+ * Try to switch to new modulation mode from MIMO2
  */
-static int rs_move_mimo_to_other(struct iwl_priv *priv,
+static int rs_move_mimo2_to_other(struct iwl_priv *priv,
 				 struct iwl_lq_sta *lq_sta,
 				 struct ieee80211_conf *conf,
 				 struct ieee80211_sta *sta, int index)
@@ -1501,7 +1627,7 @@ static int rs_move_mimo_to_other(struct iwl_priv *priv,
 		switch (tbl->action) {
 		case IWL_MIMO2_SWITCH_ANTENNA1:
 		case IWL_MIMO2_SWITCH_ANTENNA2:
-			IWL_DEBUG_RATE(priv, "LQ: MIMO toggle Antennas\n");
+			IWL_DEBUG_RATE(priv, "LQ: MIMO2 toggle Antennas\n");
 
 			if (tx_chains_num <= 2)
 				break;
@@ -1549,9 +1675,9 @@ static int rs_move_mimo_to_other(struct iwl_priv *priv,
 						HT_SHORT_GI_40MHZ))
 				break;
 
-			IWL_DEBUG_RATE(priv, "LQ: MIMO toggle SGI/NGI\n");
+			IWL_DEBUG_RATE(priv, "LQ: MIMO2 toggle SGI/NGI\n");
 
-			/* Set up new search table for MIMO */
+			/* Set up new search table for MIMO2 */
 			memcpy(search_tbl, tbl, sz);
 			search_tbl->is_SGI = !tbl->is_SGI;
 			rs_set_expected_tpt_table(lq_sta, search_tbl);
@@ -1571,9 +1697,24 @@ static int rs_move_mimo_to_other(struct iwl_priv *priv,
 						      index, is_green);
 			goto out;
 
+		case IWL_MIMO2_SWITCH_MIMO3_ABC:
+			IWL_DEBUG_RATE(priv, "LQ: MIMO2 switch to MIMO3\n");
+			memcpy(search_tbl, tbl, sz);
+			search_tbl->is_SGI = 0;
+			search_tbl->ant_type = ANT_ABC;
+
+			if (!rs_is_valid_ant(valid_tx_ant, search_tbl->ant_type))
+				break;
+
+			ret = rs_switch_to_mimo3(priv, lq_sta, conf, sta,
+						 search_tbl, index);
+			if (!ret)
+				goto out;
+
+			break;
 		}
 		tbl->action++;
-		if (tbl->action > IWL_MIMO2_SWITCH_GI)
+		if (tbl->action > IWL_MIMO2_SWITCH_MIMO3_ABC)
 			tbl->action = IWL_MIMO2_SWITCH_ANTENNA1;
 
 		if (tbl->action == start_action)
@@ -1584,12 +1725,149 @@ static int rs_move_mimo_to_other(struct iwl_priv *priv,
  out:
 	lq_sta->search_better_tbl = 1;
 	tbl->action++;
-	if (tbl->action > IWL_MIMO2_SWITCH_GI)
+	if (tbl->action > IWL_MIMO2_SWITCH_MIMO3_ABC)
 		tbl->action = IWL_MIMO2_SWITCH_ANTENNA1;
 	return 0;
 
 }
 
+/*
+ * Try to switch to new modulation mode from MIMO3
+ */
+static int rs_move_mimo3_to_other(struct iwl_priv *priv,
+				 struct iwl_lq_sta *lq_sta,
+				 struct ieee80211_conf *conf,
+				 struct ieee80211_sta *sta, int index)
+{
+	s8 is_green = lq_sta->is_green;
+	struct iwl_scale_tbl_info *tbl = &(lq_sta->lq_info[lq_sta->active_tbl]);
+	struct iwl_scale_tbl_info *search_tbl =
+				&(lq_sta->lq_info[(1 - lq_sta->active_tbl)]);
+	struct iwl_rate_scale_data *window = &(tbl->win[index]);
+	u32 sz = (sizeof(struct iwl_scale_tbl_info) -
+		  (sizeof(struct iwl_rate_scale_data) * IWL_RATE_COUNT));
+	u8 start_action = tbl->action;
+	u8 valid_tx_ant = priv->hw_params.valid_tx_ant;
+	u8 tx_chains_num = priv->hw_params.tx_chains_num;
+	int ret;
+
+	for (;;) {
+		lq_sta->action_counter++;
+		switch (tbl->action) {
+		case IWL_MIMO3_SWITCH_ANTENNA1:
+		case IWL_MIMO3_SWITCH_ANTENNA2:
+			IWL_DEBUG_RATE(priv, "LQ: MIMO3 toggle Antennas\n");
+
+			if (tx_chains_num <= 3)
+				break;
+
+			if (window->success_ratio >= IWL_RS_GOOD_RATIO)
+				break;
+
+			memcpy(search_tbl, tbl, sz);
+			if (rs_toggle_antenna(valid_tx_ant,
+				       &search_tbl->current_rate, search_tbl))
+				goto out;
+			break;
+		case IWL_MIMO3_SWITCH_SISO_A:
+		case IWL_MIMO3_SWITCH_SISO_B:
+		case IWL_MIMO3_SWITCH_SISO_C:
+			IWL_DEBUG_RATE(priv, "LQ: MIMO3 switch to SISO\n");
+
+			/* Set up new search table for SISO */
+			memcpy(search_tbl, tbl, sz);
+
+			if (tbl->action == IWL_MIMO3_SWITCH_SISO_A)
+				search_tbl->ant_type = ANT_A;
+			else if (tbl->action == IWL_MIMO3_SWITCH_SISO_B)
+				search_tbl->ant_type = ANT_B;
+			else
+				search_tbl->ant_type = ANT_C;
+
+			if (!rs_is_valid_ant(valid_tx_ant, search_tbl->ant_type))
+				break;
+
+			ret = rs_switch_to_siso(priv, lq_sta, conf, sta,
+						 search_tbl, index);
+			if (!ret)
+				goto out;
+
+			break;
+
+		case IWL_MIMO3_SWITCH_MIMO2_AB:
+		case IWL_MIMO3_SWITCH_MIMO2_AC:
+		case IWL_MIMO3_SWITCH_MIMO2_BC:
+			IWL_DEBUG_RATE(priv, "LQ: MIMO3 switch to MIMO2\n");
+
+			memcpy(search_tbl, tbl, sz);
+			search_tbl->is_SGI = 0;
+			if (tbl->action == IWL_MIMO3_SWITCH_MIMO2_AB)
+				search_tbl->ant_type = ANT_AB;
+			else if (tbl->action == IWL_MIMO3_SWITCH_MIMO2_AC)
+				search_tbl->ant_type = ANT_AC;
+			else
+				search_tbl->ant_type = ANT_BC;
+
+			if (!rs_is_valid_ant(valid_tx_ant, search_tbl->ant_type))
+				break;
+
+			ret = rs_switch_to_mimo2(priv, lq_sta, conf, sta,
+						 search_tbl, index);
+			if (!ret)
+				goto out;
+
+			break;
+
+		case IWL_MIMO3_SWITCH_GI:
+			if (!tbl->is_fat &&
+				!(priv->current_ht_config.sgf &
+						HT_SHORT_GI_20MHZ))
+				break;
+			if (tbl->is_fat &&
+				!(priv->current_ht_config.sgf &
+						HT_SHORT_GI_40MHZ))
+				break;
+
+			IWL_DEBUG_RATE(priv, "LQ: MIMO3 toggle SGI/NGI\n");
+
+			/* Set up new search table for MIMO */
+			memcpy(search_tbl, tbl, sz);
+			search_tbl->is_SGI = !tbl->is_SGI;
+			rs_set_expected_tpt_table(lq_sta, search_tbl);
+			/*
+			 * If active table already uses the fastest possible
+			 * modulation (dual stream with short guard interval),
+			 * and it's working well, there's no need to look
+			 * for a better type of modulation!
+			 */
+			if (tbl->is_SGI) {
+				s32 tpt = lq_sta->last_tpt / 100;
+				if (tpt >= search_tbl->expected_tpt[index])
+					break;
+			}
+			search_tbl->current_rate =
+				rate_n_flags_from_tbl(priv, search_tbl,
+						      index, is_green);
+			goto out;
+		}
+		tbl->action++;
+		if (tbl->action > IWL_MIMO3_SWITCH_GI)
+			tbl->action = IWL_MIMO3_SWITCH_ANTENNA1;
+
+		if (tbl->action == start_action)
+			break;
+	}
+	search_tbl->lq_type = LQ_NONE;
+	return 0;
+ out:
+	lq_sta->search_better_tbl = 1;
+	tbl->action++;
+	if (tbl->action > IWL_MIMO3_SWITCH_GI)
+		tbl->action = IWL_MIMO3_SWITCH_ANTENNA1;
+	return 0;
+
+}
+
 /*
  * Check whether we should continue using same modulation mode, or
  * begin search for a new mode, based on:
@@ -1997,8 +2275,10 @@ lq_update:
 			rs_move_legacy_other(priv, lq_sta, conf, sta, index);
 		else if (is_siso(tbl->lq_type))
 			rs_move_siso_to_other(priv, lq_sta, conf, sta, index);
+		else if (is_mimo2(tbl->lq_type))
+			rs_move_mimo2_to_other(priv, lq_sta, conf, sta, index);
 		else
-			rs_move_mimo_to_other(priv, lq_sta, conf, sta, index);
+			rs_move_mimo3_to_other(priv, lq_sta, conf, sta, index);
 
 		/* If new "search" mode was selected, set up in uCode table */
 		if (lq_sta->search_better_tbl) {
@@ -2362,6 +2642,9 @@ static void rs_fill_link_cmd(const struct iwl_priv *priv,
 	} else if (num_of_ant(tbl_type.ant_type) == 2) {
 		lq_cmd->general_params.dual_stream_ant_msk =
 						tbl_type.ant_type;
+	} else if (num_of_ant(tbl_type.ant_type) == 3) {
+		lq_cmd->general_params.dual_stream_ant_msk =
+						tbl_type.ant_type;
 	} /* otherwise we don't modify the existing value */
 
 	index++;

drivers/net/wireless/iwlwifi/iwl-agn-rs.h

@@ -241,6 +241,7 @@ enum {
 #define IWL_LEGACY_SWITCH_MIMO2_AB      3
 #define IWL_LEGACY_SWITCH_MIMO2_AC      4
 #define IWL_LEGACY_SWITCH_MIMO2_BC      5
+#define IWL_LEGACY_SWITCH_MIMO3_ABC     6
 
 /* possible actions when in siso mode */
 #define IWL_SISO_SWITCH_ANTENNA1        0
@@ -249,6 +250,8 @@ enum {
 #define IWL_SISO_SWITCH_MIMO2_AC        3
 #define IWL_SISO_SWITCH_MIMO2_BC        4
 #define IWL_SISO_SWITCH_GI              5
+#define IWL_SISO_SWITCH_MIMO3_ABC       6
+
 
 /* possible actions when in mimo mode */
 #define IWL_MIMO2_SWITCH_ANTENNA1       0
@@ -257,6 +260,21 @@ enum {
 #define IWL_MIMO2_SWITCH_SISO_B         3
 #define IWL_MIMO2_SWITCH_SISO_C         4
 #define IWL_MIMO2_SWITCH_GI             5
+#define IWL_MIMO2_SWITCH_MIMO3_ABC      6
+
+
+/* possible actions when in mimo3 mode */
+#define IWL_MIMO3_SWITCH_ANTENNA1       0
+#define IWL_MIMO3_SWITCH_ANTENNA2       1
+#define IWL_MIMO3_SWITCH_SISO_A         2
+#define IWL_MIMO3_SWITCH_SISO_B         3
+#define IWL_MIMO3_SWITCH_SISO_C         4
+#define IWL_MIMO3_SWITCH_MIMO2_AB       5
+#define IWL_MIMO3_SWITCH_MIMO2_AC       6
+#define IWL_MIMO3_SWITCH_MIMO2_BC       7
+#define IWL_MIMO3_SWITCH_GI             8
+
+
 
 /*FIXME:RS:add possible actions for MIMO3*/