mt76: mt7915: add .offset_tsf callback

It's much more accurate than .get_tsf + .set_tsf, and switch to use
mt76_rmw to operate tsf registers.
Tested-by: Xing Song <xing.song@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7915/main.c

@@ -816,7 +816,8 @@ mt7915_get_tsf(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 
 	n = mvif->omac_idx > HW_BSSID_MAX ? HW_BSSID_0 : mvif->omac_idx;
 	/* TSF software read */
-	mt76_set(dev, MT_LPON_TCR(band, n), MT_LPON_TCR_SW_MODE);
+	mt76_rmw(dev, MT_LPON_TCR(band, n), MT_LPON_TCR_SW_MODE,
+		 MT_LPON_TCR_SW_READ);
 	tsf.t32[0] = mt76_rr(dev, MT_LPON_UTTR0(band));
 	tsf.t32[1] = mt76_rr(dev, MT_LPON_UTTR1(band));
 
@@ -845,7 +846,34 @@ mt7915_set_tsf(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	mt76_wr(dev, MT_LPON_UTTR0(band), tsf.t32[0]);
 	mt76_wr(dev, MT_LPON_UTTR1(band), tsf.t32[1]);
 	/* TSF software overwrite */
-	mt76_set(dev, MT_LPON_TCR(band, n), MT_LPON_TCR_SW_WRITE);
+	mt76_rmw(dev, MT_LPON_TCR(band, n), MT_LPON_TCR_SW_MODE,
+		 MT_LPON_TCR_SW_WRITE);
+
+	mutex_unlock(&dev->mt76.mutex);
+}
+
+static void
+mt7915_offset_tsf(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
+		  s64 timestamp)
+{
+	struct mt7915_vif *mvif = (struct mt7915_vif *)vif->drv_priv;
+	struct mt7915_dev *dev = mt7915_hw_dev(hw);
+	struct mt7915_phy *phy = mt7915_hw_phy(hw);
+	bool band = phy != &dev->phy;
+	union {
+		u64 t64;
+		u32 t32[2];
+	} tsf = { .t64 = timestamp, };
+	u16 n;
+
+	mutex_lock(&dev->mt76.mutex);
+
+	n = mvif->omac_idx > HW_BSSID_MAX ? HW_BSSID_0 : mvif->omac_idx;
+	mt76_wr(dev, MT_LPON_UTTR0(band), tsf.t32[0]);
+	mt76_wr(dev, MT_LPON_UTTR1(band), tsf.t32[1]);
+	/* TSF software adjust*/
+	mt76_rmw(dev, MT_LPON_TCR(band, n), MT_LPON_TCR_SW_MODE,
+		 MT_LPON_TCR_SW_ADJUST);
 
 	mutex_unlock(&dev->mt76.mutex);
 }
@@ -1036,6 +1064,7 @@ const struct ieee80211_ops mt7915_ops = {
 	.get_stats = mt7915_get_stats,
 	.get_tsf = mt7915_get_tsf,
 	.set_tsf = mt7915_set_tsf,
+	.offset_tsf = mt7915_offset_tsf,
 	.get_survey = mt76_get_survey,
 	.get_antenna = mt76_get_antenna,
 	.set_antenna = mt7915_set_antenna,

drivers/net/wireless/mediatek/mt76/mt7915/regs.h

@@ -124,6 +124,8 @@
 #define MT_LPON_TCR(_band, n)		MT_WF_LPON(_band, 0x0a8 + (n) * 4)
 #define MT_LPON_TCR_SW_MODE		GENMASK(1, 0)
 #define MT_LPON_TCR_SW_WRITE		BIT(0)
+#define MT_LPON_TCR_SW_ADJUST		BIT(1)
+#define MT_LPON_TCR_SW_READ		GENMASK(1, 0)
 
 /* MIB: band 0(0x24800), band 1(0xa4800) */
 #define MT_WF_MIB_BASE(_band)		((_band) ? 0xa4800 : 0x24800)