ath10k: apply chainmask settings to vdev on creation

It appears it takes more than just setting the
hardware's chainmask to make things work well.  Without
this patch, a vdev would only use 1x1 rates when chainmask
was set to 0x3.

Setting the 'nss' (number of spatial streams) on the vdev
helps the firmware's rate-control algorithm work properly.
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/mac.c

@@ -2414,12 +2414,28 @@ static int ath10k_get_antenna(struct ieee80211_hw *hw, u32 *tx_ant, u32 *rx_ant)
 	return 0;
 }
 
+static void ath10k_check_chain_mask(struct ath10k *ar, u32 cm, const char *dbg)
+{
+	/* It is not clear that allowing gaps in chainmask
+	 * is helpful.  Probably it will not do what user
+	 * is hoping for, so warn in that case.
+	 */
+	if (cm == 15 || cm == 7 || cm == 3 || cm == 1 || cm == 0)
+		return;
+
+	ath10k_warn(ar, "mac %s antenna chainmask may be invalid: 0x%x.  Suggested values: 15, 7, 3, 1 or 0.\n",
+		    dbg, cm);
+}
+
 static int __ath10k_set_antenna(struct ath10k *ar, u32 tx_ant, u32 rx_ant)
 {
 	int ret;
 
 	lockdep_assert_held(&ar->conf_mutex);
 
+	ath10k_check_chain_mask(ar, tx_ant, "tx");
+	ath10k_check_chain_mask(ar, rx_ant, "rx");
+
 	ar->cfg_tx_chainmask = tx_ant;
 	ar->cfg_rx_chainmask = rx_ant;
 
@@ -2782,6 +2798,17 @@ static int ath10k_config(struct ieee80211_hw *hw, u32 changed)
 	return ret;
 }
 
+static u32 get_nss_from_chainmask(u16 chain_mask)
+{
+	if ((chain_mask & 0x15) == 0x15)
+		return 4;
+	else if ((chain_mask & 0x7) == 0x7)
+		return 3;
+	else if ((chain_mask & 0x3) == 0x3)
+		return 2;
+	return 1;
+}
+
 /*
  * TODO:
  * Figure out how to handle WMI_VDEV_SUBTYPE_P2P_DEVICE,
@@ -2914,6 +2941,20 @@ static int ath10k_add_interface(struct ieee80211_hw *hw,
 		goto err_vdev_delete;
 	}
 
+	if (ar->cfg_tx_chainmask) {
+		u16 nss = get_nss_from_chainmask(ar->cfg_tx_chainmask);
+
+		vdev_param = ar->wmi.vdev_param->nss;
+		ret = ath10k_wmi_vdev_set_param(ar, arvif->vdev_id, vdev_param,
+						nss);
+		if (ret) {
+			ath10k_warn(ar, "failed to set vdev %i chainmask 0x%x, nss %i: %d\n",
+				    arvif->vdev_id, ar->cfg_tx_chainmask, nss,
+				    ret);
+			goto err_vdev_delete;
+		}
+	}
+
 	if (arvif->vdev_type == WMI_VDEV_TYPE_AP) {
 		ret = ath10k_peer_create(ar, arvif->vdev_id, vif->addr);
 		if (ret) {