wifi: mac80211_hwsim: add incumbent signal interference detection support

Add a debugfs 'simulate_incumbent_signal_interference' with custom
file_operations and a .write that accepts "<freq_mhz> <bitmap>". The
handler selects the 6 GHz chanctx whose primary 20 MHz center matches
<freq_mhz> and reports the event via cfg80211_incumbent_signal_notify().
The bitmap marks affected 20 MHz segments within the current chandef
(lowest bit = lowest segment)

Signed-off-by: Aditya Kumar Singh <aditya.kumar.singh@oss.qualcomm.com>
Signed-off-by: Amith A <amith.a@oss.qualcomm.com>
Link: https://patch.msgid.link/20260306060927.504567-2-amith.a@oss.qualcomm.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/net/wireless/virtual/mac80211_hwsim.c b/drivers/net/wireless/virtual/mac80211_hwsim.c
index 32897d88bda3..82adcc848189 100644
--- a/drivers/net/wireless/virtual/mac80211_hwsim.c
+++ b/drivers/net/wireless/virtual/mac80211_hwsim.c
@@ -36,6 +36,8 @@
 #include <linux/virtio.h>
 #include <linux/virtio_ids.h>
 #include <linux/virtio_config.h>
+#include <linux/uaccess.h>
+#include <linux/string.h>
 #include "mac80211_hwsim.h"
 
 #define WARN_QUEUE 100
@@ -1203,6 +1205,65 @@ static const struct file_operations hwsim_background_cac_ops = {
 	.llseek = default_llseek,
 };
 
+struct hwsim_chanctx_iter_arg {
+	struct ieee80211_chanctx_conf *conf;
+	u32 freq_mhz;
+};
+
+static void hwsim_6ghz_chanctx_iter(struct ieee80211_hw *hw,
+				    struct ieee80211_chanctx_conf *conf,
+				    void *data)
+{
+	struct hwsim_chanctx_iter_arg *arg = data;
+
+	if (conf->def.chan &&
+	    conf->def.chan->band == NL80211_BAND_6GHZ &&
+	    conf->def.chan->center_freq == arg->freq_mhz)
+		arg->conf = conf;
+}
+
+static ssize_t hwsim_simulate_incumbent_signal_write(struct file *file,
+						     const char __user *ubuf,
+						     size_t len, loff_t *ppos)
+{
+	struct mac80211_hwsim_data *data = file->private_data;
+	struct hwsim_chanctx_iter_arg arg = {};
+	u32 bitmap;
+	char buf[64];
+
+	if (!len || len > sizeof(buf) - 1)
+		return -EINVAL;
+
+	if (copy_from_user(buf, ubuf, len))
+		return -EFAULT;
+	buf[len] = '\0';
+
+	if (sscanf(buf, "%u %i", &arg.freq_mhz, &bitmap) != 2)
+		return -EINVAL;
+
+	if (!arg.freq_mhz)
+		return -EINVAL;
+
+	ieee80211_iter_chan_contexts_atomic(data->hw,
+					    hwsim_6ghz_chanctx_iter,
+					    &arg);
+
+	if (!arg.conf)
+		return -EINVAL;
+
+	cfg80211_incumbent_signal_notify(data->hw->wiphy,
+					 &arg.conf->def,
+					 bitmap,
+					 GFP_KERNEL);
+
+	return len;
+}
+
+static const struct file_operations hwsim_simulate_incumbent_signal_fops = {
+	.open	= simple_open,
+	.write	= hwsim_simulate_incumbent_signal_write,
+};
+
 static int hwsim_fops_group_read(void *dat, u64 *val)
 {
 	struct mac80211_hwsim_data *data = dat;
@@ -5950,6 +6011,9 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
 		debugfs_create_file("dfs_background_cac", 0200,
 				    data->debugfs,
 				    data, &hwsim_background_cac_ops);
+	debugfs_create_file("simulate_incumbent_signal_interference", 0200,
+			    data->debugfs,
+			    data, &hwsim_simulate_incumbent_signal_fops);
 
 	if (param->pmsr_capa) {
 		data->pmsr_capa = *param->pmsr_capa;