mt76: mt7915: add debugfs knob for RF registers read/write

Add RF registers read/write support for debugging RF issues, which
should be processed by mcu commands.
The index of rf registers use the generic regidx, and are combined
with two parts: WF selection [31:28] and offset [27:0].

Reviewed-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Peter Chiu <chui-hao.chiu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -867,6 +867,36 @@ mt7915_twt_stats(struct seq_file *s, void *data)
 	return 0;
 }
 
+/* The index of RF registers use the generic regidx, combined with two parts:
+ * WF selection [31:28] and offset [27:0].
+ */
+static int
+mt7915_rf_regval_get(void *data, u64 *val)
+{
+	struct mt7915_dev *dev = data;
+	u32 regval;
+	int ret;
+
+	ret = mt7915_mcu_rf_regval(dev, dev->mt76.debugfs_reg, &regval, false);
+	if (ret)
+		return ret;
+
+	*val = le32_to_cpu(regval);
+
+	return 0;
+}
+
+static int
+mt7915_rf_regval_set(void *data, u64 val)
+{
+	struct mt7915_dev *dev = data;
+
+	return mt7915_mcu_rf_regval(dev, dev->mt76.debugfs_reg, (u32 *)&val, true);
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(fops_rf_regval, mt7915_rf_regval_get,
+			 mt7915_rf_regval_set, "0x%08llx\n");
+
 int mt7915_init_debugfs(struct mt7915_phy *phy)
 {
 	struct mt7915_dev *dev = phy->dev;
@@ -898,6 +928,8 @@ int mt7915_init_debugfs(struct mt7915_phy *phy)
 	debugfs_create_devm_seqfile(dev->mt76.dev, "twt_stats", dir,
 				    mt7915_twt_stats);
 	debugfs_create_file("ser_trigger", 0200, dir, dev, &fops_ser_trigger);
+	debugfs_create_file("rf_regval", 0600, dir, dev, &fops_rf_regval);
+
 	if (!dev->dbdc_support || phy->band_idx) {
 		debugfs_create_u32("dfs_hw_pattern", 0400, dir,
 				   &dev->hw_pattern);

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

@@ -3661,3 +3661,32 @@ int mt7915_mcu_twt_agrt_update(struct mt7915_dev *dev,
 	return mt76_mcu_send_msg(&dev->mt76, MCU_EXT_CMD(TWT_AGRT_UPDATE),
 				 &req, sizeof(req), true);
 }
+
+int mt7915_mcu_rf_regval(struct mt7915_dev *dev, u32 regidx, u32 *val, bool set)
+{
+	struct {
+		__le32 idx;
+		__le32 ofs;
+		__le32 data;
+	} __packed req = {
+		.idx = cpu_to_le32(u32_get_bits(regidx, GENMASK(31, 28))),
+		.ofs = cpu_to_le32(u32_get_bits(regidx, GENMASK(27, 0))),
+		.data = set ? cpu_to_le32(*val) : 0,
+	};
+	struct sk_buff *skb;
+	int ret;
+
+	if (set)
+		return mt76_mcu_send_msg(&dev->mt76, MCU_EXT_CMD(RF_REG_ACCESS),
+					 &req, sizeof(req), false);
+
+	ret = mt76_mcu_send_and_get_msg(&dev->mt76, MCU_EXT_QUERY(RF_REG_ACCESS),
+					&req, sizeof(req), true, &skb);
+	if (ret)
+		return ret;
+
+	*val = le32_to_cpu(*(__le32 *)(skb->data + 8));
+	dev_kfree_skb(skb);
+
+	return 0;
+}

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

@@ -506,6 +506,7 @@ int mt7915_mcu_get_rx_rate(struct mt7915_phy *phy, struct ieee80211_vif *vif,
 			   struct ieee80211_sta *sta, struct rate_info *rate);
 int mt7915_mcu_rdd_background_enable(struct mt7915_phy *phy,
 				     struct cfg80211_chan_def *chandef);
+int mt7915_mcu_rf_regval(struct mt7915_dev *dev, u32 regidx, u32 *val, bool set);
 int mt7915_mcu_wa_cmd(struct mt7915_dev *dev, int cmd, u32 a1, u32 a2, u32 a3);
 int mt7915_mcu_fw_log_2_host(struct mt7915_dev *dev, u8 type, u8 ctrl);
 int mt7915_mcu_fw_dbg_ctrl(struct mt7915_dev *dev, u32 module, u8 level);