[PATCH v2 3/3] mt76: mt7915: directly read per-rate tx power from registers

[Shayne Chen <shayne.chen@xxxxxxxxxxxx>]

In the previous version, the values of per-rate tx power are calculated
from SW side, but it may be inaccurate if additional limits are applied.
This patch adds support for getting per-rate tx power directly from
registers.

Tested-by: Evelyn Tsai <evelyn.tsai@xxxxxxxxxxxx>
Signed-off-by: Shayne Chen <shayne.chen@xxxxxxxxxxxx>
---
v2:
 - fix reg_base and idx calculation
---
 .../wireless/mediatek/mt76/mt7915/debugfs.c   | 63 ++++++++++++-------
 .../net/wireless/mediatek/mt76/mt7915/regs.h  |  5 ++
 2 files changed, 45 insertions(+), 23 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
index 6d4fd14..92affd4 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
@@ -300,8 +300,8 @@ mt7915_queues_read(struct seq_file *s, void *data)
 }
 
 static void
-mt7915_puts_rate_txpower(struct seq_file *s, s8 *delta,
-			 s8 txpower_cur, int band)
+mt7915_puts_rate_txpower(struct seq_file *s, struct mt7915_dev *dev,
+			 int band, bool ext_phy)
 {
 	static const char * const sku_group_name[] = {
 		"CCK", "OFDM", "HT20", "HT40",
@@ -309,24 +309,46 @@ mt7915_puts_rate_txpower(struct seq_file *s, s8 *delta,
 		"RU26", "RU52", "RU106", "RU242/SU20",
 		"RU484/SU40", "RU996/SU80", "RU2x996/SU160"
 	};
-	s8 txpower[MT7915_SKU_RATE_NUM];
+	u32 reg_base = MT_TMAC_FP0R0(ext_phy);
 	int i, idx = 0;
 
-	for (i = 0; i < MT7915_SKU_RATE_NUM; i++)
-		txpower[i] = DIV_ROUND_UP(txpower_cur + delta[i], 2);
+	for (i = 0; i < ARRAY_SIZE(mt7915_sku_group_len); i++) {
+		u8 cnt, mcs_num = mt7915_sku_group_len[i];
+		s8 txpower[12];
+		int j;
+
+		if (i == SKU_HT_BW20 || i == SKU_HT_BW40) {
+			mcs_num = 8;
+		} else if (i >= SKU_VHT_BW20 && i <= SKU_VHT_BW160) {
+			mcs_num = 10;
+		} else if (i == SKU_HE_RU26) {
+			reg_base = MT_TMAC_FP0R18(ext_phy);
+			idx = 0;
+		}
 
-	for (i = 0; i < MAX_SKU_RATE_GROUP_NUM; i++) {
-		const struct sku_group *sku = &mt7915_sku_groups[i];
-		u32 offset = sku->offset[band];
+		for (j = 0, cnt = 0; j < DIV_ROUND_UP(mcs_num, 4); j++) {
+			u32 val;
 
-		if (!offset) {
-			idx += sku->len;
-			continue;
+			if (i == SKU_VHT_BW160 && idx == 60) {
+				reg_base = MT_TMAC_FP0R15(ext_phy);
+				idx = 0;
+			}
+
+			val = mt76_rr(dev, reg_base + (idx / 4) * 4);
+
+			if (idx && idx % 4)
+				val >>= (idx % 4) * 8;
+
+			while (val > 0 && cnt < mcs_num) {
+				s8 pwr = FIELD_GET(MT_TMAC_FP_MASK, val);
+
+				txpower[cnt++] = pwr;
+				val >>= 8;
+				idx++;
+			}
 		}
 
-		mt76_seq_puts_array(s, sku_group_name[i],
-				    txpower + idx, sku->len);
-		idx += sku->len;
+		mt76_seq_puts_array(s, sku_group_name[i], txpower, mcs_num);
 	}
 }
 
@@ -336,21 +358,16 @@ mt7915_read_rate_txpower(struct seq_file *s, void *data)
 	struct mt7915_dev *dev = dev_get_drvdata(s->private);
 	struct mt76_phy *mphy = &dev->mphy;
 	enum nl80211_band band = mphy->chandef.chan->band;
-	s8 *delta = dev->rate_power[band];
-	s8 txpower_base = mphy->txpower_cur - delta[161];
 
-	seq_puts(s, "Band 0:\n");
-	mt7915_puts_rate_txpower(s, delta, txpower_base, band);
+	seq_puts(s, "Band 0: (unit: 0.5 dBm)\n");
+	mt7915_puts_rate_txpower(s, dev, band, false);
 
 	if (dev->mt76.phy2) {
 		mphy = dev->mt76.phy2;
 		band = mphy->chandef.chan->band;
-		delta = dev->rate_power[band];
-		txpower_base = mphy->txpower_cur -
-			       delta[161];
 
-		seq_puts(s, "Band 1:\n");
-		mt7915_puts_rate_txpower(s, delta, txpower_base, band);
+		seq_puts(s, "Band 1: (unit: 0.5 dBm)\n");
+		mt7915_puts_rate_txpower(s, dev, band, true);
 	}
 
 	return 0;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/regs.h b/drivers/net/wireless/mediatek/mt76/mt7915/regs.h
index c121715..d80ae1e 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/regs.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/regs.h
@@ -67,6 +67,11 @@
 #define MT_TMAC_CTCR0_INS_DDLMT_EN		BIT(17)
 #define MT_TMAC_CTCR0_INS_DDLMT_VHT_SMPDU_EN	BIT(18)
 
+#define MT_TMAC_FP0R0(_band)		MT_WF_TMAC(_band, 0x020)
+#define MT_TMAC_FP0R15(_band)		MT_WF_TMAC(_band, 0x080)
+#define MT_TMAC_FP0R18(_band)		MT_WF_TMAC(_band, 0x270)
+#define MT_TMAC_FP_MASK			GENMASK(7, 0)
+
 /* DMA Band 0 */
 #define MT_WF_DMA_BASE			0x21e00
 #define MT_WF_DMA(ofs)			(MT_WF_DMA_BASE + (ofs))
-- 
2.17.1