rtw89: Limit the CFO boundaries of x'tal value

Set the boundaries of x'tal value to avoid extremely adjusted results,
causing severely unexpected CFO.
Signed-off-by: Yi-Tang Chiu <chiuyitang@realtek.com>
Signed-off-by: Yuan-Han Zhang <yuanhan1020@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220218034537.9338-1-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/core.h

@@ -2613,6 +2613,10 @@ struct rtw89_cfo_tracking_info {
 	s32 residual_cfo_acc;
 	u8 phy_cfotrk_state;
 	u8 phy_cfotrk_cnt;
+	bool divergence_lock_en;
+	u8 x_cap_lb;
+	u8 x_cap_ub;
+	u8 lock_cnt;
 };
 
 /* 2GL, 2GH, 5GL1, 5GH1, 5GM1, 5GM2, 5GH1, 5GH2 */

drivers/net/wireless/realtek/rtw89/phy.c

@@ -1743,8 +1743,12 @@ static void rtw89_phy_cfo_init(struct rtw89_dev *rtwdev)
 	cfo->crystal_cap_default = efuse->xtal_cap & B_AX_XTAL_SC_MASK;
 	cfo->crystal_cap = cfo->crystal_cap_default;
 	cfo->def_x_cap = cfo->crystal_cap;
+	cfo->x_cap_ub = min_t(int, cfo->def_x_cap + CFO_BOUND, 0x7f);
+	cfo->x_cap_lb = max_t(int, cfo->def_x_cap - CFO_BOUND, 0x1);
 	cfo->is_adjust = false;
+	cfo->divergence_lock_en = false;
 	cfo->x_cap_ofst = 0;
+	cfo->lock_cnt = 0;
 	cfo->rtw89_multi_cfo_mode = RTW89_TP_BASED_AVG_MODE;
 	cfo->apply_compensation = false;
 	cfo->residual_cfo_acc = 0;
@@ -1962,6 +1966,23 @@ static void rtw89_phy_cfo_dm(struct rtw89_dev *rtwdev)
 		rtw89_debug(rtwdev, RTW89_DBG_CFO, "curr_cfo=0\n");
 		return;
 	}
+	if (cfo->divergence_lock_en) {
+		cfo->lock_cnt++;
+		if (cfo->lock_cnt > CFO_PERIOD_CNT) {
+			cfo->divergence_lock_en = false;
+			cfo->lock_cnt = 0;
+		} else {
+			rtw89_phy_cfo_reset(rtwdev);
+		}
+		return;
+	}
+	if (cfo->crystal_cap >= cfo->x_cap_ub ||
+	    cfo->crystal_cap <= cfo->x_cap_lb) {
+		cfo->divergence_lock_en = true;
+		rtw89_phy_cfo_reset(rtwdev);
+		return;
+	}
+
 	rtw89_phy_cfo_crystal_cap_adjust(rtwdev, new_cfo);
 	cfo->cfo_avg_pre = new_cfo;
 	x_cap_update =  cfo->crystal_cap != pre_x_cap;

drivers/net/wireless/realtek/rtw89/phy.h

@@ -55,6 +55,7 @@
 #define CFO_TRK_STOP_TH (2 << 2)
 #define CFO_SW_COMP_FINE_TUNE (2 << 2)
 #define CFO_PERIOD_CNT 15
+#define CFO_BOUND 32
 #define CFO_TP_UPPER 100
 #define CFO_TP_LOWER 50
 #define CFO_COMP_PERIOD 250