ieee802154: add support for listen-before-talk in wpan_phy

Listen-before-talk is an alternative to CSMA in uncoordinated networks
and prescribed by european regulations if one wants to have a device
with radio duty cycles above 10% (or less in some bands). Add a phy
property to enable/disable LBT in the phy, including support in the
at86rf230 driver for RF212 chips.

Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 47 insertions, 12 deletions

diff --git a/net/ieee802154/nl-phy.c b/net/ieee802154/nl-phy.c
index d3ee62f..f029310 100644
--- a/net/ieee802154/nl-phy.c
+++ b/net/ieee802154/nl-phy.c
@@ -56,7 +56,8 @@ static int ieee802154_nl_fill_phy(struct sk_buff *msg, u32 portid,
 	if (nla_put_string(msg, IEEE802154_ATTR_PHY_NAME, wpan_phy_name(phy)) ||
 	    nla_put_u8(msg, IEEE802154_ATTR_PAGE, phy->current_page) ||
 	    nla_put_u8(msg, IEEE802154_ATTR_CHANNEL, phy->current_channel) ||
-	    nla_put_s8(msg, IEEE802154_ATTR_TXPOWER, phy->transmit_power))
+	    nla_put_s8(msg, IEEE802154_ATTR_TXPOWER, phy->transmit_power) ||
+	    nla_put_u8(msg, IEEE802154_ATTR_LBT_ENABLED, phy->lbt))
 		goto nla_put_failure;
 	for (i = 0; i < 32; i++) {
 		if (phy->channels_supported[i])
@@ -356,40 +357,71 @@ out_dev:
 	return rc;
 }
 
+static int phy_set_txpower(struct wpan_phy *phy, struct genl_info *info)
+{
+	int txpower = nla_get_s8(info->attrs[IEEE802154_ATTR_TXPOWER]);
+	int rc;
+
+	rc = phy->set_txpower(phy, txpower);
+	if (rc < 0)
+		return rc;
+
+	phy->transmit_power = txpower;
+
+	return 0;
+}
+
+static int phy_set_lbt(struct wpan_phy *phy, struct genl_info *info)
+{
+	u8 on = !!nla_get_u8(info->attrs[IEEE802154_ATTR_LBT_ENABLED]);
+	int rc;
+
+	rc = phy->set_lbt(phy, on);
+	if (rc < 0)
+		return rc;
+
+	phy->lbt = on;
+
+	return 0;
+}
+
 int ieee802154_set_phyparams(struct sk_buff *skb, struct genl_info *info)
 {
 	struct wpan_phy *phy;
 	const char *name;
-	int txpower;
-	int rc = -EINVAL;
+	int rc = -ENOTSUPP;
 
 	pr_debug("%s\n", __func__);
 
-	if (!info->attrs[IEEE802154_ATTR_PHY_NAME])
+	if (!info->attrs[IEEE802154_ATTR_PHY_NAME] &&
+	    !info->attrs[IEEE802154_ATTR_LBT_ENABLED])
 		return -EINVAL;
 
 	name = nla_data(info->attrs[IEEE802154_ATTR_PHY_NAME]);
 	if (name[nla_len(info->attrs[IEEE802154_ATTR_PHY_NAME]) - 1] != '\0')
 		return -EINVAL; /* phy name should be null-terminated */
 
-	txpower = nla_get_s8(info->attrs[IEEE802154_ATTR_TXPOWER]);
-
 	phy = wpan_phy_find(name);
 	if (!phy)
 		return -ENODEV;
 
-	if (!phy->set_txpower)
+	if ((!phy->set_txpower && info->attrs[IEEE802154_ATTR_TXPOWER]) ||
+	    (!phy->set_lbt && info->attrs[IEEE802154_ATTR_LBT_ENABLED]))
 		goto out;
 
 	mutex_lock(&phy->pib_lock);
 
-	rc = phy->set_txpower(phy, txpower);
-	if (rc < 0) {
-		mutex_unlock(&phy->pib_lock);
-		goto out;
+	if (info->attrs[IEEE802154_ATTR_TXPOWER]) {
+		rc = phy_set_txpower(phy, info);
+		if (rc < 0)
+			goto error;
 	}
 
-	phy->transmit_power = txpower;
+	if (info->attrs[IEEE802154_ATTR_LBT_ENABLED]) {
+		rc = phy_set_lbt(phy, info);
+		if (rc < 0)
+			goto error;
+	}
 
 	mutex_unlock(&phy->pib_lock);
 
@@ -397,6 +429,8 @@ int ieee802154_set_phyparams(struct sk_buff *skb, struct genl_info *info)
 
 	return 0;
 
+error:
+	mutex_unlock(&phy->pib_lock);
 out:
 	wpan_phy_put(phy);
 	return rc;
diff --git a/net/ieee802154/nl_policy.c b/net/ieee802154/nl_policy.c
index 90b1d0d..a09f642 100644
--- a/net/ieee802154/nl_policy.c
+++ b/net/ieee802154/nl_policy.c
@@ -54,5 +54,6 @@ const struct nla_policy ieee802154_policy[IEEE802154_ATTR_MAX + 1] = {
 	[IEEE802154_ATTR_CHANNEL_PAGE_LIST] = { .len = 32 * 4, },
 
 	[IEEE802154_ATTR_TXPOWER] = { .type = NLA_S8, },
+	[IEEE802154_ATTR_LBT_ENABLED] = { .type = NLA_U8, },
 };