qca-wifi-oss: Fix preCAC channel list building

As part of preCAC forest building in pine, 160MHz root nodes
were introduced to support 160 ADFS.

To support different BW root nodes in the preCAC forest,
an API (dfs_fill_max_bw_info_for_chan) was introduced to find
every cluster of channels. i.e, every unique 160, 80,
40, 20MHz channels available in the regdomain.

This API loops through different BWs for a given primary channel
and updates the maximum BW for the primary channel and it's
corresponding center frequency. The API then skips all
the primary channels within this range (primary frequency + BW)
and goes to the next primary channel that is not in the range
and start finding the maximum BW of this channel.

After all these operations, a set of center frequencies and it's
maximum BW will be found. This data will be used to build the
preCAC forest.

While looping through different channels with the same primary,
the BW value was updated only if it's greater than the existing
maximum, but the center was always updated.

Consider a case where, for primary channel 36, the current
center is 5250MHz and it's BW is 160MHz. Now, if a new channel
structure with 36 as primary and mode as 80+80MHz, the center
is updated as 5210MHz but BW is not updated, since the new BW
(80MHz) is less than the existing BW (160MHz).
Now the center is 5210MHz but the BW is 160MHz which results in
a faulty preCAC forest.

Update the center frequency only if the maximum BW value
is changed. Also, update the index of the frequency and BW
list (dfs_max_bw_info) to start from 0 instead of starting from 1. Hence,
num_precac_roots will reduce by 1 as the index is starting from 0.

Change-Id: I50503d0cd7ebe18890216952e2193e611f7f209a
CRs-Fixed: 2674087

umac/dfs/core/src/misc/dfs_zero_cac.c

@@ -2668,6 +2668,19 @@ struct dfs_channel_bw {
 	uint16_t dfs_max_bw;
 };
 
+/* dfs_calculate_bw_for_same_pri_ch() - When the primary channel is a new
+ * channel initialize the center channel frequency and bandwidth and when the
+ * primary is same as previous channel update the center frequency and the
+ * bandwith.
+ * @dfs:               WLAN DFS structure
+ * @dfs_max_bw_info:   Structure to store precac tree root channel's
+ * information.
+ * @index:             The index that is manipulated.
+ * @ichan:             The DFS channel structure that holds the primary channel
+ *                     number, center frquency and channel bandwidth.
+ * @delimiter:         Band gap in MHz from the current primary channel to next
+ *                     primary channel.
+ */
 static void
 dfs_calculate_bw_for_same_pri_ch(struct wlan_dfs *dfs,
 				 struct dfs_channel_bw *dfs_max_bw_info,
@@ -2676,9 +2689,10 @@ dfs_calculate_bw_for_same_pri_ch(struct wlan_dfs *dfs,
 				 int *delimiter)
 {
 	uint8_t temp_bw = 0;
+	uint16_t tmp_center_freq;
 
 	dfs_max_bw_info[index].dfs_pri_ch_freq = ichan->dfs_ch_freq;
-	dfs_max_bw_info[index].dfs_center_ch_freq = ichan->dfs_ch_mhz_freq_seg1;
+	tmp_center_freq = ichan->dfs_ch_mhz_freq_seg1;
 
 	if (WLAN_IS_CHAN_MODE_20(ichan)) {
 		temp_bw = DFS_CHWIDTH_20_VAL;
@@ -2694,18 +2708,18 @@ dfs_calculate_bw_for_same_pri_ch(struct wlan_dfs *dfs,
 	    (ichan->dfs_ch_vhtop_ch_freq_seg2 ==
 	     RESTRICTED_80P80_RIGHT_80_CENTER_CHAN)) {
 		temp_bw = DFS_CHWIDTH_165_VAL;
-		dfs_max_bw_info[index].dfs_center_ch_freq =
-			RESTRICTED_80P80_CHAN_CENTER_FREQ;
+		tmp_center_freq = RESTRICTED_80P80_CHAN_CENTER_FREQ;
 		}
 	} else if (WLAN_IS_CHAN_MODE_160(ichan)) {
 		temp_bw = DFS_CHWIDTH_160_VAL;
-		dfs_max_bw_info[index].dfs_center_ch_freq =
-			ichan->dfs_ch_mhz_freq_seg2;
+		tmp_center_freq = ichan->dfs_ch_mhz_freq_seg2;
 	}
-	if (temp_bw > dfs_max_bw_info[index].dfs_max_bw)
+	if (temp_bw > dfs_max_bw_info[index].dfs_max_bw) {
 		dfs_max_bw_info[index].dfs_max_bw = temp_bw;
-	*delimiter = dfs_max_bw_info[index].dfs_pri_ch_freq +
-	dfs_max_bw_info[index].dfs_max_bw;
+		*delimiter = dfs_max_bw_info[index].dfs_pri_ch_freq +
+			     dfs_max_bw_info[index].dfs_max_bw;
+		dfs_max_bw_info[index].dfs_center_ch_freq = tmp_center_freq;
+	}
 }
 
 /* dfs_fill_max_bw_for_chan() - Finds unique precac tree node in the channel
@@ -2721,11 +2735,19 @@ static void dfs_fill_max_bw_for_chan(struct wlan_dfs *dfs,
 				     struct dfs_channel_bw *dfs_max_bw_info,
 				     int *num_precac_roots)
 {
-	int nchans = 0, i, j = 0, prev_ch_freq = 0, delimiter = 0;
+	int i;
+	int n_total_chans = 0;
+	int  n_chanseg_found = 0;
+	int prev_ch_freq = 0;
+	int delimiter = 0;
 
-	dfs_mlme_get_dfs_ch_nchans(dfs->dfs_pdev_obj, &nchans);
-	for (i = 0; i < nchans; i++) {
+	dfs_mlme_get_dfs_ch_nchans(dfs->dfs_pdev_obj, &n_total_chans);
+	for (i = 0; i < n_total_chans; i++) {
 		struct dfs_channel *ichan = NULL, lc;
+		/* The array index of the bandwidth list that needs to be
+		 * updated.
+		 */
+		int index_to_update;
 
 		ichan = &lc;
 		dfs_mlme_get_dfs_channels_for_freq
@@ -2742,19 +2764,42 @@ static void dfs_fill_max_bw_for_chan(struct wlan_dfs *dfs,
 		if (!WLAN_IS_PRIMARY_OR_SECONDARY_CHAN_DFS(ichan))
 			continue;
 		if (ichan->dfs_ch_freq == prev_ch_freq) {
+			/* When the primary channels are common for consecutive
+			 * channels, for example 36HT20, 36HT40, 36HT80,...,
+			 * only the center frequecy and the bandwidth have to be
+			 * updated.
+			 */
+			index_to_update = n_chanseg_found - 1;
 			dfs_calculate_bw_for_same_pri_ch(dfs,
 							 dfs_max_bw_info,
-							 j,
+							 index_to_update,
 							 ichan,
 							 &delimiter);
 		} else if (ichan->dfs_ch_freq < delimiter) {
 			continue;
 		} else {
 			prev_ch_freq = ichan->dfs_ch_freq;
-			j++;
+			/* When the primary channels are unique and consecutive
+			 * like 149HT20, 153HT20, 157HT20,..., the new element
+			 * has to be initialized here.
+			 */
+			index_to_update = n_chanseg_found;
+			dfs_calculate_bw_for_same_pri_ch(dfs,
+							 dfs_max_bw_info,
+							 n_chanseg_found,
+							 ichan,
+							 &delimiter);
+			n_chanseg_found++;
 		}
 	}
-	*num_precac_roots = j + 1;
+	*num_precac_roots = n_chanseg_found;
+	for (i = 0; i < *num_precac_roots; i++)
+		dfs_debug(dfs, WLAN_DEBUG_DFS,
+			  "index = %d pri: %d centr: %d bw: %d",
+			  i,
+			  dfs_max_bw_info[i].dfs_pri_ch_freq,
+			  dfs_max_bw_info[i].dfs_center_ch_freq,
+			  dfs_max_bw_info[i].dfs_max_bw);
 }
 
 static QDF_STATUS
@@ -2777,15 +2822,13 @@ dfs_precac_create_precac_entry(struct wlan_dfs *dfs,
 					    precac_entry->center_ch_freq,
 					    &precac_entry->tree_root,
 					    precac_entry->bw);
-	if (status) {
+	if (status)
 		dfs_debug(dfs, WLAN_DEBUG_DFS,
 			  "PreCAC entry for channel %d not created",
 			  precac_entry->center_ch_ieee);
-	} else {
-	    TAILQ_INSERT_TAIL(
-		    &dfs->dfs_precac_list,
-		    precac_entry, pe_list);
-	}
+	else
+	    TAILQ_INSERT_TAIL(&dfs->dfs_precac_list, precac_entry, pe_list);
+
 	return status;
 }