From 0e01d6aa229b84b92c9462f7101314db62857b86 Mon Sep 17 00:00:00 2001
From: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
Date: Mon, 20 Mar 2023 16:08:30 +0800
Subject: [PATCH 20/54] mtk: hostapd: Fix ZWDFS issue in BW 160

When background radar is enabled and bandwidth is set to 160, AP will
fail to startup due to the lack of non-DFS channel.
Under this circumstance, AP should perform CAC itself, and the background
chain could also perform CAC simultaneously.

Signed-off-by: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
---
 src/ap/dfs.c | 98 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 79 insertions(+), 19 deletions(-)

diff --git a/src/ap/dfs.c b/src/ap/dfs.c
index 9d002cfad..3b1df6dc6 100644
--- a/src/ap/dfs.c
+++ b/src/ap/dfs.c
@@ -69,15 +69,22 @@ static int dfs_get_used_n_chans(struct hostapd_iface *iface, int *seg1)
 static int dfs_channel_available(struct hostapd_channel_data *chan,
 				 enum dfs_channel_type type)
 {
+	int dfs_status = chan->flag & HOSTAPD_CHAN_DFS_MASK;
+
+	if (chan->flag & HOSTAPD_CHAN_DISABLED)
+		return -1;
+
 	if (type == DFS_NO_CAC_YET) {
 		/* Select only radar channel where CAC has not been
 		 * performed yet
 		 */
-		if ((chan->flag & HOSTAPD_CHAN_RADAR) &&
-		    (chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
-		     HOSTAPD_CHAN_DFS_USABLE)
+		if (!(chan->flag & HOSTAPD_CHAN_RADAR))
+			return 0;
+
+		if (dfs_status == HOSTAPD_CHAN_DFS_USABLE)
 			return 1;
-		return 0;
+
+		return -1;
 	}
 
 	/*
@@ -86,16 +93,14 @@ static int dfs_channel_available(struct hostapd_channel_data *chan,
 	 * channel for CSA, unless they are available for immediate use.
 	 */
 	if (type == DFS_AVAILABLE && (chan->flag & HOSTAPD_CHAN_RADAR) &&
-	    ((chan->flag & HOSTAPD_CHAN_DFS_MASK) !=
-	     HOSTAPD_CHAN_DFS_AVAILABLE))
-		return 0;
+	    (dfs_status != HOSTAPD_CHAN_DFS_AVAILABLE))
+		return -1;
 
-	if (chan->flag & HOSTAPD_CHAN_DISABLED)
-		return 0;
 	if ((chan->flag & HOSTAPD_CHAN_RADAR) &&
-	    ((chan->flag & HOSTAPD_CHAN_DFS_MASK) ==
-	     HOSTAPD_CHAN_DFS_UNAVAILABLE))
-		return 0;
+	    ((dfs_status == HOSTAPD_CHAN_DFS_UNAVAILABLE) ||
+	    (dfs_status == HOSTAPD_CHAN_DFS_UNKNOWN)))
+		return -1;
+
 	return 1;
 }
 
@@ -167,7 +172,7 @@ static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
 				    enum dfs_channel_type type)
 {
 	struct hostapd_channel_data *first_chan, *chan;
-	int i;
+	int i, available = 0, ret = 0;
 	u32 bw = num_chan_to_bw(num_chans);
 
 	if (first_chan_idx + num_chans > mode->num_channels) {
@@ -203,14 +208,17 @@ static int dfs_chan_range_available(struct hostapd_hw_modes *mode,
 			return 0;
 		}
 
-		if (!dfs_channel_available(chan, type)) {
+		ret = dfs_channel_available(chan, type);
+		if (ret < 0) {
 			wpa_printf(MSG_DEBUG, "DFS: channel not available %d",
 				   first_chan->freq + i * 20);
 			return 0;
 		}
+
+		available |= ret;
 	}
 
-	return 1;
+	return available;
 }
 
 
@@ -836,8 +844,12 @@ static unsigned int dfs_get_cac_time(struct hostapd_iface *iface,
  */
 int hostapd_handle_dfs(struct hostapd_iface *iface)
 {
+	struct hostapd_channel_data *channel;
 	int res, n_chans, n_chans1, start_chan_idx, start_chan_idx1;
-	int skip_radar = 0;
+	int sec = 0, skip_radar = 0;
+	u8 cf1 = 0, cf2 = 0;
+	bool use_radar_background = dfs_use_radar_background(iface);
+	enum dfs_channel_type channel_type = DFS_NO_CAC_YET;
 
 	if (is_6ghz_freq(iface->freq))
 		return 1;
@@ -900,7 +912,7 @@ int hostapd_handle_dfs(struct hostapd_iface *iface)
 	/* Finally start CAC */
 	hostapd_set_state(iface, HAPD_IFACE_DFS);
 	wpa_printf(MSG_DEBUG, "DFS start CAC on %d MHz%s", iface->freq,
-		   dfs_use_radar_background(iface) ? " (background)" : "");
+		   use_radar_background ? " (background)" : "");
 	wpa_msg(iface->bss[0]->msg_ctx, MSG_INFO, DFS_EVENT_CAC_START
 		"freq=%d chan=%d sec_chan=%d, width=%d, seg0=%d, seg1=%d, cac_time=%ds",
 		iface->freq,
@@ -910,6 +922,16 @@ int hostapd_handle_dfs(struct hostapd_iface *iface)
 		hostapd_get_oper_centr_freq_seg1_idx(iface->conf),
 		iface->dfs_cac_ms / 1000);
 
+	if (use_radar_background) {
+		channel = dfs_get_valid_channel(iface, &sec, &cf1, &cf2, DFS_AVAILABLE);
+		/*
+		 * AP cannot get any random available channel.
+		 * Let AP and dedicated radar chain both perform CAC.
+		 */
+		if (!channel)
+			use_radar_background = false;
+	}
+
 	res = hostapd_start_dfs_cac(
 		iface, iface->conf->hw_mode, iface->freq, iface->conf->channel,
 		iface->conf->ieee80211n, iface->conf->ieee80211ac,
@@ -918,14 +940,14 @@ int hostapd_handle_dfs(struct hostapd_iface *iface)
 		hostapd_get_oper_chwidth(iface->conf),
 		hostapd_get_oper_centr_freq_seg0_idx(iface->conf),
 		hostapd_get_oper_centr_freq_seg1_idx(iface->conf),
-		dfs_use_radar_background(iface));
+		use_radar_background);
 
 	if (res) {
 		wpa_printf(MSG_ERROR, "DFS start_dfs_cac() failed, %d", res);
 		return -1;
 	}
 
-	if (dfs_use_radar_background(iface)) {
+	if (use_radar_background) {
 		/* Cache background radar parameters. */
 		iface->radar_background.channel = iface->conf->channel;
 		iface->radar_background.secondary_channel =
@@ -946,6 +968,35 @@ int hostapd_handle_dfs(struct hostapd_iface *iface)
 
 		iface->radar_background.temp_ch = 1;
 		return 1;
+	} else if (dfs_use_radar_background(iface)) {
+		if (iface->dfs_domain == HOSTAPD_DFS_REGION_ETSI)
+			channel_type = DFS_ANY_CHANNEL;
+
+		channel = dfs_get_valid_channel(iface, &sec, &cf1, &cf2, channel_type);
+
+		if (!channel ||
+		    (channel->chan == iface->conf->channel &&
+		    cf1 == hostapd_get_oper_centr_freq_seg0_idx(iface->conf) &&
+		    cf2 == hostapd_get_oper_centr_freq_seg1_idx(iface->conf))) {
+			wpa_printf(MSG_ERROR, "Background radar could not get valid channel\n");
+			iface->radar_background.channel = -1;
+			return 0;
+		}
+
+		hostapd_start_dfs_cac(iface, iface->conf->hw_mode,
+				      channel->freq, channel->chan,
+				      iface->conf->ieee80211n,
+				      iface->conf->ieee80211ac,
+				      iface->conf->ieee80211ax,
+				      iface->conf->ieee80211be,
+				      sec, hostapd_get_oper_chwidth(iface->conf),
+				      cf1, cf2, true);
+
+		iface->radar_background.channel = channel->chan;
+		iface->radar_background.freq = channel->freq;
+		iface->radar_background.secondary_channel = sec;
+		iface->radar_background.centr_freq_seg0_idx = cf1;
+		iface->radar_background.centr_freq_seg1_idx = cf2;
 	}
 
 	return 0;
@@ -1195,6 +1246,15 @@ int hostapd_dfs_complete_cac(struct hostapd_iface *iface, int success, int freq,
 				hostapd_setup_interface_complete(iface, 0);
 				iface->cac_started = 0;
 			}
+
+			/*
+			 * When background radar is enabled but the CAC completion
+			 * is not received from the background chain.
+			 * Then, reset radar background chain.
+			 */
+			if (dfs_use_radar_background(iface) &&
+			    iface->radar_background.channel == -1)
+				hostpad_dfs_update_background_chain(iface);
 		}
 	} else if (hostapd_dfs_is_background_event(iface, freq)) {
 		iface->radar_background.cac_started = 0;
-- 
2.18.0