mt76: mt7921: add .set_sar_specs support

add .set_sar_specs to allow configuring SAR power limitations on the
frequency ranges from the userland.
Co-developed-by: NSean Wang <sean.wang@mediatek.com>
Signed-off-by: NSean Wang <sean.wang@mediatek.com>
Signed-off-by: NYN Chen <YN.Chen@mediatek.com>
Signed-off-by: NFelix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mac80211.c

@@ -99,6 +99,21 @@ struct ieee80211_rate mt76_rates[] = {
 };
 EXPORT_SYMBOL_GPL(mt76_rates);
 
+static const struct cfg80211_sar_freq_ranges mt76_sar_freq_ranges[] = {
+	{ .start_freq = 2402, .end_freq = 2494, },
+	{ .start_freq = 5150, .end_freq = 5350, },
+	{ .start_freq = 5350, .end_freq = 5470, },
+	{ .start_freq = 5470, .end_freq = 5725, },
+	{ .start_freq = 5725, .end_freq = 5950, },
+};
+
+const struct cfg80211_sar_capa mt76_sar_capa = {
+	.type = NL80211_SAR_TYPE_POWER,
+	.num_freq_ranges = ARRAY_SIZE(mt76_sar_freq_ranges),
+	.freq_ranges = &mt76_sar_freq_ranges[0],
+};
+EXPORT_SYMBOL_GPL(mt76_sar_capa);
+
 static int mt76_led_init(struct mt76_dev *dev)
 {
 	struct device_node *np = dev->dev->of_node;

drivers/net/wireless/mediatek/mt76/mt76.h

@@ -545,6 +545,11 @@ struct mt76_rx_status {
 	s8 chain_signal[IEEE80211_MAX_CHAINS];
 };
 
+struct mt76_freq_range_power {
+	const struct cfg80211_sar_freq_ranges *range;
+	s8 power;
+};
+
 struct mt76_testmode_ops {
 	int (*set_state)(struct mt76_phy *phy, enum mt76_testmode_state state);
 	int (*set_params)(struct mt76_phy *phy, struct nlattr **tb,
@@ -636,6 +641,8 @@ struct mt76_phy {
 		struct sk_buff **tail;
 		u16 seqno;
 	} rx_amsdu[__MT_RXQ_MAX];
+
+	struct mt76_freq_range_power *frp;
 };
 
 struct mt76_dev {
@@ -769,6 +776,7 @@ enum mt76_phy_type {
 }
 
 extern struct ieee80211_rate mt76_rates[12];
+extern const struct cfg80211_sar_capa mt76_sar_capa;
 
 #define __mt76_rr(dev, ...)	(dev)->bus->rr((dev), __VA_ARGS__)
 #define __mt76_wr(dev, ...)	(dev)->bus->wr((dev), __VA_ARGS__)

drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c

@@ -1749,6 +1749,30 @@ mt76_connac_mcu_build_sku(struct mt76_dev *dev, s8 *sku,
 	}
 }
 
+static s8 mt76_connac_get_sar_power(struct mt76_phy *phy,
+				    struct ieee80211_channel *chan,
+				    s8 target_power)
+{
+	const struct cfg80211_sar_capa *capa = phy->hw->wiphy->sar_capa;
+	struct mt76_freq_range_power *frp = phy->frp;
+	int freq, i;
+
+	if (!capa || !frp)
+		return target_power;
+
+	freq = ieee80211_channel_to_frequency(chan->hw_value, chan->band);
+	for (i = 0 ; i < capa->num_freq_ranges; i++) {
+		if (frp[i].range &&
+		    freq >= frp[i].range->start_freq &&
+		    freq < frp[i].range->end_freq) {
+			target_power = min_t(s8, frp[i].power, target_power);
+			break;
+		}
+	}
+
+	return target_power;
+}
+
 static int
 mt76_connac_mcu_rate_txpower_band(struct mt76_phy *phy,
 				  enum nl80211_band band)
@@ -1816,10 +1840,14 @@ mt76_connac_mcu_rate_txpower_band(struct mt76_phy *phy,
 				.hw_value = ch_list[idx],
 				.band = band,
 			};
+			s8 sar_power;
 
-			mt76_get_rate_power_limits(phy, &chan, &limits,
+			sar_power = mt76_connac_get_sar_power(phy, &chan,
 							      tx_power);
 
+			mt76_get_rate_power_limits(phy, &chan, &limits,
+						   sar_power);
+
 			tx_power_tlv.last_msg = ch_list[idx] == last_ch;
 			sku_tlbv.channel = ch_list[idx];
 

drivers/net/wireless/mediatek/mt76/mt7921/init.c

@@ -41,7 +41,7 @@ mt7921_regd_notifier(struct wiphy *wiphy,
 	mt7921_mutex_release(dev);
 }
 
-static void
+static int
 mt7921_init_wiphy(struct ieee80211_hw *hw)
 {
 	struct mt7921_phy *phy = mt7921_hw_phy(hw);
@@ -75,6 +75,14 @@ mt7921_init_wiphy(struct ieee80211_hw *hw)
 	wiphy->max_sched_scan_reqs = 1;
 	wiphy->flags |= WIPHY_FLAG_HAS_CHANNEL_SWITCH;
 	wiphy->reg_notifier = mt7921_regd_notifier;
+	wiphy->sar_capa = &mt76_sar_capa;
+
+	phy->mt76->frp = devm_kcalloc(dev->mt76.dev,
+				      wiphy->sar_capa->num_freq_ranges,
+				      sizeof(struct mt76_freq_range_power),
+				      GFP_KERNEL);
+	if (!phy->mt76->frp)
+		return -ENOMEM;
 
 	wiphy->features |= NL80211_FEATURE_SCHED_SCAN_RANDOM_MAC_ADDR |
 			   NL80211_FEATURE_SCAN_RANDOM_MAC_ADDR;
@@ -92,6 +100,8 @@ mt7921_init_wiphy(struct ieee80211_hw *hw)
 		ieee80211_hw_set(hw, CONNECTION_MONITOR);
 
 	hw->max_tx_fragments = 4;
+
+	return 0;
 }
 
 static void
@@ -211,7 +221,10 @@ int mt7921_register_device(struct mt7921_dev *dev)
 	if (ret)
 		return ret;
 
-	mt7921_init_wiphy(hw);
+	ret = mt7921_init_wiphy(hw);
+	if (ret)
+		return ret;
+
 	dev->mphy.sband_2g.sband.ht_cap.cap |=
 			IEEE80211_HT_CAP_LDPC_CODING |
 			IEEE80211_HT_CAP_MAX_AMSDU;

drivers/net/wireless/mediatek/mt76/mt7921/main.c

@@ -1172,6 +1172,43 @@ static void mt7921_sta_set_decap_offload(struct ieee80211_hw *hw,
 					     MCU_UNI_CMD_STA_REC_UPDATE);
 }
 
+static int mt7921_set_sar_specs(struct ieee80211_hw *hw,
+				const struct cfg80211_sar_specs *sar)
+{
+	const struct cfg80211_sar_capa *capa = hw->wiphy->sar_capa;
+	struct mt7921_dev *dev = mt7921_hw_dev(hw);
+	struct mt76_freq_range_power *data, *frp;
+	struct mt76_phy *mphy = hw->priv;
+	int err;
+	u32 i;
+
+	if (sar->type != NL80211_SAR_TYPE_POWER || !sar->num_sub_specs)
+		return -EINVAL;
+
+	mt7921_mutex_acquire(dev);
+
+	data = mphy->frp;
+
+	for (i = 0; i < sar->num_sub_specs; i++) {
+		u32 index = sar->sub_specs[i].freq_range_index;
+		/* SAR specifies power limitaton in 0.25dbm */
+		s32 power = sar->sub_specs[i].power >> 1;
+
+		if (power > 127 || power < -127)
+			power = 127;
+
+		frp = &data[index];
+		frp->range = &capa->freq_ranges[index];
+		frp->power = power;
+	}
+
+	err = mt76_connac_mcu_set_rate_txpower(mphy);
+
+	mt7921_mutex_release(dev);
+
+	return err;
+}
+
 const struct ieee80211_ops mt7921_ops = {
 	.tx = mt7921_tx,
 	.start = mt7921_start,
@@ -1210,4 +1247,5 @@ const struct ieee80211_ops mt7921_ops = {
 	.set_rekey_data = mt7921_set_rekey_data,
 #endif /* CONFIG_PM */
 	.flush = mt7921_flush,
+	.set_sar_specs = mt7921_set_sar_specs,
 };