From eca521242b94855825f085d1bca67a5958420baa Mon Sep 17 00:00:00 2001
From: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
Date: Thu, 22 Sep 2022 14:27:41 +0800
Subject: [PATCH] cfg80211: implement DFS status show, cac and nop skip command
 via debugfs

Signed-off-by: StanleyYP Wang <StanleyYP.Wang@mediatek.com>
---
 net/wireless/debugfs.c | 228 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 221 insertions(+), 7 deletions(-)

diff --git a/net/wireless/debugfs.c b/net/wireless/debugfs.c
index aab4346..19c3091 100644
--- a/net/wireless/debugfs.c
+++ b/net/wireless/debugfs.c
@@ -95,16 +95,230 @@ static const struct file_operations ht40allow_map_ops = {
 	.llseek = default_llseek,
 };
 
-#define DEBUGFS_ADD(name)						\
-	debugfs_create_file(#name, 0444, phyd, &rdev->wiphy, &name## _ops)
+static int dfs_print_chan(struct ieee80211_channel *chan, int remain_time,
+			  char *buf, int buf_size, int offset)
+{
+	if (WARN_ON(offset > buf_size))
+		return 0;
+
+	if (chan->dfs_state == NL80211_DFS_UNAVAILABLE) {
+		offset += scnprintf(buf + offset, buf_size - offset,
+				    "	Channel = %d, DFS_state = Unavailable",
+				    chan->hw_value);
+		if (remain_time > 0)
+			offset += scnprintf(buf + offset, buf_size - offset,
+					    ", Non-occupancy Remain Time = %d [sec]\n",
+					    remain_time);
+		else
+			offset += scnprintf(buf + offset, buf_size - offset,
+					    ", Changing state...\n");
+	} else if (chan->dfs_state == NL80211_DFS_USABLE) {
+		offset += scnprintf(buf + offset, buf_size - offset,
+				    "	Channel = %d, DFS_state = Usable",
+				    chan->hw_value);
+		if (remain_time > 0)
+			offset += scnprintf(buf + offset, buf_size - offset,
+					    ", CAC Remain Time = %d [sec]\n",
+					    remain_time);
+		else
+			offset += scnprintf(buf + offset, buf_size - offset,
+					    "\n");
+	} else if (chan->dfs_state == NL80211_DFS_AVAILABLE) {
+		offset += scnprintf(buf + offset, buf_size - offset,
+				    "	Channel = %d, DFS_state = Available\n",
+				    chan->hw_value);
+	} else {
+		offset += scnprintf(buf + offset, buf_size - offset,
+				    "	Channel = %d, DFS_state = Unknown\n",
+				    chan->hw_value);
+	}
+
+	return offset;
+}
+
+static int dfs_status_read_wdev(struct wiphy *wiphy, struct wireless_dev *wdev, char *buf,
+				unsigned int buf_size, unsigned int offset)
+{
+	struct cfg80211_chan_def *chandef;
+	enum nl80211_band band;
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_channel *chan;
+	unsigned long jiffies_passed;
+	int i, remain_time = 0;
+
+	offset += scnprintf(buf + offset, buf_size - offset, "DFS Channel:\n");
+
+	for (band = 0; band < NUM_NL80211_BANDS; band++) {
+		sband = wiphy->bands[band];
+		if (!sband)
+			continue;
+		for (i = 0; i < sband->n_channels; i++) {
+			chan = &sband->channels[i];
+
+			if (!(chan->flags & IEEE80211_CHAN_RADAR))
+				continue;
+
+			if (chan->dfs_state == NL80211_DFS_UNAVAILABLE) {
+				jiffies_passed = jiffies - chan->dfs_state_entered;
+				remain_time = (IEEE80211_DFS_MIN_NOP_TIME_MS -
+					       jiffies_to_msecs(jiffies_passed));
+				if (remain_time > IEEE80211_DFS_MIN_NOP_TIME_MS)
+					remain_time = 0;
+			} else if (chan->dfs_state == NL80211_DFS_USABLE) {
+				chandef = &wdev->chandef;
+				if (wdev->cac_started && cfg80211_is_sub_chan(chandef, chan)) {
+					jiffies_passed = jiffies - wdev->cac_start_time;
+					remain_time = (wdev->cac_time_ms -
+							jiffies_to_msecs(jiffies_passed));
+				}
+				if (remain_time > wdev->cac_time_ms)
+					remain_time = 0;
+			}
+			offset = dfs_print_chan(chan, remain_time / 1000, buf, buf_size, offset);
+			remain_time = 0;
+		}
+	}
+
+	return offset;
+}
+
+static ssize_t dfs_status_read(struct file *file, char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	struct wiphy *wiphy = file->private_data;
+	struct wireless_dev *wdev;
+	char *buf;
+	unsigned int offset = 0, buf_size = PAGE_SIZE, r;
+	const char * const iftype_str[] = {
+		[NL80211_IFTYPE_UNSPECIFIED] = "unspecified",
+		[NL80211_IFTYPE_ADHOC] = "adhoc",
+		[NL80211_IFTYPE_STATION] = "station",
+		[NL80211_IFTYPE_AP] = "ap",
+		[NL80211_IFTYPE_AP_VLAN] = "ap vlan",
+		[NL80211_IFTYPE_WDS] = "wds",
+		[NL80211_IFTYPE_MONITOR] = "monitor",
+		[NL80211_IFTYPE_MESH_POINT] = "mesh point",
+		[NL80211_IFTYPE_P2P_CLIENT] = "p2p client",
+		[NL80211_IFTYPE_P2P_GO] = "p2p go",
+		[NL80211_IFTYPE_P2P_DEVICE] = "p2p device",
+		[NL80211_IFTYPE_OCB] = "ocb",
+		[NL80211_IFTYPE_NAN] = "nan",
+	};
+
+	buf = kzalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	list_for_each_entry(wdev, &wiphy->wdev_list, list) {
+		offset += scnprintf(buf + offset, buf_size - offset,
+				    "wdev 0x%x\n"
+				    "interface type %s\n",
+				    wdev->identifier, iftype_str[wdev->iftype]);
+		offset = dfs_status_read_wdev(wiphy, wdev, buf, buf_size, offset);
+	}
+
+	r = simple_read_from_buffer(user_buf, count, ppos, buf, offset);
+
+	kfree(buf);
+
+	return r;
+}
+
+static const struct file_operations dfs_status_ops = {
+	.read = dfs_status_read,
+	.open = simple_open,
+	.llseek = default_llseek,
+};
+
+static int
+dfs_nop_skip(void *data, u64 val)
+{
+	struct wiphy *wiphy = data;
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+	bool en = !!val;
+	enum nl80211_band band;
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_channel *chan;
+	u32 nop_time = IEEE80211_DFS_MIN_NOP_TIME_MS;
+	int i;
+
+	if (!en)
+		return 0;
+
+	for (band = 0; band < NUM_NL80211_BANDS; band++) {
+		sband = wiphy->bands[band];
+		if (!sband)
+			continue;
+		for (i = 0; i < sband->n_channels; i++) {
+			chan = &sband->channels[i];
+
+			if (!(chan->flags & IEEE80211_CHAN_RADAR))
+				continue;
+
+			if (chan->dfs_state == NL80211_DFS_UNAVAILABLE) {
+				// Let current jiffies > dfs_state_entered_jiffies + NOP time
+				chan->dfs_state_entered = jiffies -
+						       msecs_to_jiffies(nop_time + 1);
+			}
+		}
+	}
+
+	cfg80211_sched_dfs_chan_update(rdev);
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(dfs_skip_nop_ops, NULL,
+			 dfs_nop_skip, "0x%08llx\n");
+
+static int
+dfs_cac_skip(void *data, u64 val)
+{
+	struct wiphy *wiphy = data;
+	struct wireless_dev *wdev;
+	struct cfg80211_chan_def *chandef;
+	bool en = !!val;
+	struct ieee80211_channel *chan;
+
+	if (!en)
+		return 0;
+
+	list_for_each_entry(wdev, &wiphy->wdev_list, list) {
+		chandef = &wdev->chandef;
+		if (chandef->chan) {
+			chan = chandef->chan;
+			if (!(chan->flags & IEEE80211_CHAN_RADAR))
+				continue;
+
+			if (chan->dfs_state == NL80211_DFS_USABLE && wdev->cac_started) {
+				// Let current jiffies > dfs_state_entered_jiffies + CAC time
+				wdev->cac_start_time = jiffies -
+						       msecs_to_jiffies(wdev->cac_time_ms + 1);
+				cfg80211_cac_event(wdev->netdev, chandef,
+						   NL80211_RADAR_CAC_FINISHED, GFP_KERNEL);
+			}
+		}
+	}
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(dfs_skip_cac_ops, NULL,
+			 dfs_cac_skip, "0x%08llx\n");
+
+#define DEBUGFS_ADD(name, chmod)						\
+	debugfs_create_file(#name, chmod, phyd, &rdev->wiphy, &name## _ops)
 
 void cfg80211_debugfs_rdev_add(struct cfg80211_registered_device *rdev)
 {
 	struct dentry *phyd = rdev->wiphy.debugfsdir;
 
-	DEBUGFS_ADD(rts_threshold);
-	DEBUGFS_ADD(fragmentation_threshold);
-	DEBUGFS_ADD(short_retry_limit);
-	DEBUGFS_ADD(long_retry_limit);
-	DEBUGFS_ADD(ht40allow_map);
+	DEBUGFS_ADD(rts_threshold, 0444);
+	DEBUGFS_ADD(fragmentation_threshold, 0444);
+	DEBUGFS_ADD(short_retry_limit, 0444);
+	DEBUGFS_ADD(long_retry_limit, 0444);
+	DEBUGFS_ADD(ht40allow_map, 0444);
+	DEBUGFS_ADD(dfs_status, 0444);
+	DEBUGFS_ADD(dfs_skip_nop, 0600);
+	DEBUGFS_ADD(dfs_skip_cac, 0600);
 }
-- 
2.18.0