2 files changed, 42 insertions, 0 deletions

diff --git a/net/ieee802154/nl802154.c b/net/ieee802154/nl802154.c
index d1cf3021ff36..af383553bdd2 100644
--- a/net/ieee802154/nl802154.c
+++ b/net/ieee802154/nl802154.c
@@ -642,6 +642,31 @@ nl802154_set_backoff_exponent(struct sk_buff *skb, struct genl_info *info)
         return rdev_set_backoff_exponent(rdev, wpan_dev, min_be, max_be);
 }
 
+static int
+nl802154_set_max_csma_backoffs(struct sk_buff *skb, struct genl_info *info)
+{
+        struct cfg802154_registered_device *rdev = info->user_ptr[0];
+        struct net_device *dev = info->user_ptr[1];
+        struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
+        u8 max_csma_backoffs;
+
+        /* conflict here while other running iface settings */
+        if (netif_running(dev))
+                return -EBUSY;
+
+        if (!info->attrs[NL802154_ATTR_MAX_CSMA_BACKOFFS])
+                return -EINVAL;
+
+        max_csma_backoffs = nla_get_u8(
+                        info->attrs[NL802154_ATTR_MAX_CSMA_BACKOFFS]);
+
+        /* check 802.15.4 constraints */
+        if (max_csma_backoffs > 5)
+                return -EINVAL;
+
+        return rdev_set_max_csma_backoffs(rdev, wpan_dev, max_csma_backoffs);
+}
+
 #define NL802154_FLAG_NEED_WPAN_PHY     0x01
 #define NL802154_FLAG_NEED_NETDEV       0x02
 #define NL802154_FLAG_NEED_RTNL         0x04
@@ -784,6 +809,14 @@ static const struct genl_ops nl802154_ops[] = {
                 .internal_flags = NL802154_FLAG_NEED_NETDEV |
                                   NL802154_FLAG_NEED_RTNL,
         },
+        {
+                .cmd = NL802154_CMD_SET_MAX_CSMA_BACKOFFS,
+                .doit = nl802154_set_max_csma_backoffs,
+                .policy = nl802154_policy,
+                .flags = GENL_ADMIN_PERM,
+                .internal_flags = NL802154_FLAG_NEED_NETDEV |
+                                  NL802154_FLAG_NEED_RTNL,
+        },
 };
 
 /* initialisation/exit functions */
diff --git a/net/ieee802154/rdev-ops.h b/net/ieee802154/rdev-ops.h
index dbccfa9383fd..263095c8686c 100644
--- a/net/ieee802154/rdev-ops.h
+++ b/net/ieee802154/rdev-ops.h
@@ -50,4 +50,13 @@ rdev_set_backoff_exponent(struct cfg802154_registered_device *rdev,
                                                min_be, max_be);
 }
 
+static inline int
+rdev_set_max_csma_backoffs(struct cfg802154_registered_device *rdev,
+                           struct wpan_dev *wpan_dev,
+                           const u8 max_csma_backoffs)
+{
+        return rdev->ops->set_max_csma_backoffs(&rdev->wpan_phy, wpan_dev,
+                                                max_csma_backoffs);
+}
+
 #endif /* __CFG802154_RDEV_OPS */