1 files changed, 106 insertions, 0 deletions
diff --git a/drivers/net/wireless/realtek/rtw89/util.c b/drivers/net/wireless/realtek/rtw89/util.c
new file mode 100644
index 000000000000..e71956ce9853
--- /dev/null
+++ b/drivers/net/wireless/realtek/rtw89/util.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/* Copyright(c) 2024  Realtek Corporation
+ */
+
+#include "util.h"
+
+#define FRAC_ROWS 3
+#define FRAC_ROW_MAX (FRAC_ROWS - 1)
+#define NORM_ROW_MIN FRAC_ROWS
+
+static const u32 db_invert_table[12][8] = {
+	/* rows 0~2 in unit of U(32,3) */
+	{10, 13, 16, 20, 25, 32, 40, 50},
+	{64, 80, 101, 128, 160, 201, 256, 318},
+	{401, 505, 635, 800, 1007, 1268, 1596, 2010},
+	/* rows 3~11 in unit of U(32,0) */
+	{316, 398, 501, 631, 794, 1000, 1259, 1585},
+	{1995, 2512, 3162, 3981, 5012, 6310, 7943, 10000},
+	{12589, 15849, 19953, 25119, 31623, 39811, 50119, 63098},
+	{79433, 100000, 125893, 158489, 199526, 251189, 316228, 398107},
+	{501187, 630957, 794328, 1000000, 1258925, 1584893, 1995262, 2511886},
+	{3162278, 3981072, 5011872, 6309573, 7943282, 1000000, 12589254,
+	 15848932},
+	{19952623, 25118864, 31622777, 39810717, 50118723, 63095734, 79432823,
+	 100000000},
+	{125892541, 158489319, 199526232, 251188643, 316227766, 398107171,
+	 501187234, 630957345},
+	{794328235, 1000000000, 1258925412, 1584893192, 1995262315, 2511886432U,
+	 3162277660U, 3981071706U},
+};
+
+u32 rtw89_linear_2_db(u64 val)
+{
+	u8 i, j;
+	u32 dB;
+
+	for (i = 0; i < 12; i++) {
+		for (j = 0; j < 8; j++) {
+			if (i <= FRAC_ROW_MAX &&
+			    (val << RTW89_LINEAR_FRAC_BITS) <= db_invert_table[i][j])
+				goto cnt;
+			else if (i > FRAC_ROW_MAX && val <= db_invert_table[i][j])
+				goto cnt;
+		}
+	}
+
+	return 96; /* maximum 96 dB */
+
+cnt:
+	/* special cases */
+	if (j == 0 && i == 0)
+		goto end;
+
+	if (i == NORM_ROW_MIN && j == 0) {
+		if (db_invert_table[NORM_ROW_MIN][0] - val >
+		    val - (db_invert_table[FRAC_ROW_MAX][7] >> RTW89_LINEAR_FRAC_BITS)) {
+			i = FRAC_ROW_MAX;
+			j = 7;
+		}
+		goto end;
+	}
+
+	if (i <= FRAC_ROW_MAX)
+		val <<= RTW89_LINEAR_FRAC_BITS;
+
+	/* compare difference to get precise dB */
+	if (j == 0) {
+		if (db_invert_table[i][j] - val >
+		    val - db_invert_table[i - 1][7]) {
+			i--;
+			j = 7;
+		}
+	} else {
+		if (db_invert_table[i][j] - val >
+		    val - db_invert_table[i][j - 1]) {
+			j--;
+		}
+	}
+end:
+	dB = (i << 3) + j + 1;
+
+	return dB;
+}
+EXPORT_SYMBOL(rtw89_linear_2_db);
+
+u64 rtw89_db_2_linear(u32 db)
+{
+	u64 linear;
+	u8 i, j;
+
+	if (db > 96)
+		db = 96;
+	else if (db < 1)
+		return 1;
+
+	i = (db - 1) >> 3;
+	j = (db - 1) & 0x7;
+
+	linear = db_invert_table[i][j];
+
+	if (i >= NORM_ROW_MIN)
+		linear = linear << RTW89_LINEAR_FRAC_BITS;
+
+	return linear;
+}
+EXPORT_SYMBOL(rtw89_db_2_linear);