From b08463cf3f68a3a5ba7fef6dacb77dff239ffd48 Mon Sep 17 00:00:00 2001
From: Yuvarani V <quic_yuvarani@quicinc.com>
Date: Wed, 27 Sep 2023 12:52:03 +0530
Subject: hostapd: mtk: Update Wide Bandwidth Channel Switch element

This patch is from hostapd upstream
(https://w1.fi/cgit/hostap/commit/src/ap/ieee802_11.c?id=ef8d48c4cfe673420dcec2879cbc8c84b16e041d)

Original commit message:
Update Wide Bandwidth Channel Switch element as per IEEE
P802.11-REVme/D4.0, 9.4.2.159 (Wide Bandwidth Channel Switch element)
and Table 9-314 (VHT Operation Information subfields).

Update New Channel Width, New Channel Center Frequency Segment 0, and
New Channel Center Frequency Segment 1 fields as per IEEE
P802.11-REVme/D4.0 for 160 MHz and 80+80 MHz bandwidth. This replaces
the use of now deprecated Channel Width 2 and 3 values with a more
backwards compatible design.

Signed-off-by: Yuvarani V <quic_yuvarani@quicinc.com>
---
 src/ap/ieee802_11.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/ap/ieee802_11.c b/src/ap/ieee802_11.c
index dd477fd..8a5fd20 100644
--- a/src/ap/ieee802_11.c
+++ b/src/ap/ieee802_11.c
@@ -7176,7 +7176,7 @@ u8 * hostapd_eid_txpower_envelope(struct hostapd_data *hapd, u8 *eid)
 
 u8 * hostapd_eid_wb_chsw_wrapper(struct hostapd_data *hapd, u8 *eid)
 {
-	u8 bw, chan1, chan2 = 0;
+	u8 bw, chan1 = 0, chan2 = 0;
 	int freq1;
 
 	if (!hapd->cs_freq_params.channel ||
@@ -7185,20 +7185,17 @@ u8 * hostapd_eid_wb_chsw_wrapper(struct hostapd_data *hapd, u8 *eid)
 	     !hapd->cs_freq_params.eht_enabled))
 		return eid;
 
-	/* bandwidth: 0: 40, 1: 80, 2: 160, 3: 80+80 */
+	/* bandwidth: 0: 40, 1: 80, 160, 80+80, 4: 320 as per
+	 * IEEE P802.11-REVme/D4.0, 9.4.2.159 and Table 9-314. */
 	switch (hapd->cs_freq_params.bandwidth) {
 	case 40:
 		bw = 0;
 		break;
 	case 80:
-		/* check if it's 80+80 */
-		if (!hapd->cs_freq_params.center_freq2)
-			bw = 1;
-		else
-			bw = 3;
+		bw = 1;
 		break;
 	case 160:
-		bw = 2;
+		bw = 1;
 		break;
 	default:
 		/* not valid VHT bandwidth or not in CSA */
@@ -7222,6 +7219,21 @@ u8 * hostapd_eid_wb_chsw_wrapper(struct hostapd_data *hapd, u8 *eid)
 	*eid++ = WLAN_EID_VHT_WIDE_BW_CHSWITCH;
 	*eid++ = 3; /* Length of Wide Bandwidth Channel Switch element */
 	*eid++ = bw; /* New Channel Width */
+	if (hapd->cs_freq_params.bandwidth == 160) {
+		/* Update the CCFS0 and CCFS1 values in the element based on
+		 * IEEE P802.11-REVme/D4.0, Table 9-314 */
+
+		/* CCFS1 - The channel center frequency index of the 160 MHz
+		 * channel. */
+		chan2 = chan1;
+
+		/* CCFS0 - The channel center frequency index of the 80 MHz
+		 * channel segment that contains the primary channel. */
+		if (hapd->cs_freq_params.channel < chan1)
+			chan1 -= 8;
+		else
+			chan1 += 8;
+	}
 	*eid++ = chan1; /* New Channel Center Frequency Segment 0 */
 	*eid++ = chan2; /* New Channel Center Frequency Segment 1 */
 
-- 
2.25.1