iwlwifi: mvm: support setting minimum quota from debugfs

For debug purposes, allow setting minimum quota (for a single
virtual interface) from debugfs. This is an absolute minimum,
so it can only be set up to 95%.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
index c286a5f..1400445 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
@@ -1372,6 +1372,59 @@
 	return simple_read_from_buffer(user_buf, count, ppos, buf, sizeof(buf));
 }
 
+static void iwl_dbgfs_quota_check(void *data, u8 *mac,
+				  struct ieee80211_vif *vif)
+{
+	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+	int *ret = data;
+
+	if (mvmvif->dbgfs_quota_min)
+		*ret = -EINVAL;
+}
+
+static ssize_t iwl_dbgfs_quota_min_write(struct ieee80211_vif *vif, char *buf,
+					 size_t count, loff_t *ppos)
+{
+	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+	struct iwl_mvm *mvm = mvmvif->mvm;
+	u16 value;
+	int ret;
+
+	ret = kstrtou16(buf, 0, &value);
+	if (ret)
+		return ret;
+
+	if (value > 95)
+		return -EINVAL;
+
+	mutex_lock(&mvm->mutex);
+
+	mvmvif->dbgfs_quota_min = 0;
+	ieee80211_iterate_interfaces(mvm->hw, IEEE80211_IFACE_ITER_NORMAL,
+				     iwl_dbgfs_quota_check, &ret);
+	if (ret == 0) {
+		mvmvif->dbgfs_quota_min = value;
+		iwl_mvm_update_quotas(mvm, false, NULL);
+	}
+	mutex_unlock(&mvm->mutex);
+
+	return ret ?: count;
+}
+
+static ssize_t iwl_dbgfs_quota_min_read(struct file *file,
+					char __user *user_buf,
+					size_t count, loff_t *ppos)
+{
+	struct ieee80211_vif *vif = file->private_data;
+	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+	char buf[10];
+	int len;
+
+	len = snprintf(buf, sizeof(buf), "%d\n", mvmvif->dbgfs_quota_min);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
 #define MVM_DEBUGFS_WRITE_FILE_OPS(name, bufsz) \
 	_MVM_DEBUGFS_WRITE_FILE_OPS(name, bufsz, struct ieee80211_vif)
 #define MVM_DEBUGFS_READ_WRITE_FILE_OPS(name, bufsz) \
@@ -1395,6 +1448,7 @@
 MVM_DEBUGFS_READ_WRITE_FILE_OPS(tof_range_abort, 32);
 MVM_DEBUGFS_READ_FILE_OPS(tof_range_response);
 MVM_DEBUGFS_READ_WRITE_FILE_OPS(tof_responder_params, 32);
+MVM_DEBUGFS_READ_WRITE_FILE_OPS(quota_min, 32);
 
 void iwl_mvm_vif_dbgfs_register(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
 {
@@ -1432,6 +1486,8 @@
 				 S_IRUSR | S_IWUSR);
 	MVM_DEBUGFS_ADD_FILE_VIF(rx_phyinfo, mvmvif->dbgfs_dir,
 				 S_IRUSR | S_IWUSR);
+	MVM_DEBUGFS_ADD_FILE_VIF(quota_min, mvmvif->dbgfs_dir,
+				 S_IRUSR | S_IWUSR);
 
 	if (vif->type == NL80211_IFTYPE_STATION && !vif->p2p &&
 	    mvmvif == mvm->bf_allowed_vif)