NFC: Add a target lost netlink event

Some chips are capable of detecting when a tag is out of the field, so
they could send a netlink event about it to userspace.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 6404052d6c07..ebdb605f8dbd 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -183,6 +183,36 @@ free_msg:
         return -EMSGSIZE;
 }
 
+int nfc_genl_target_lost(struct nfc_dev *dev, u32 target_idx)
+{
+        struct sk_buff *msg;
+        void *hdr;
+
+        msg = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
+        if (!msg)
+                return -ENOMEM;
+
+        hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
+                          NFC_EVENT_TARGET_LOST);
+        if (!hdr)
+                goto free_msg;
+
+        NLA_PUT_STRING(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev));
+        NLA_PUT_U32(msg, NFC_ATTR_TARGET_INDEX, target_idx);
+
+        genlmsg_end(msg, hdr);
+
+        genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);
+
+        return 0;
+
+nla_put_failure:
+        genlmsg_cancel(msg, hdr);
+free_msg:
+        nlmsg_free(msg);
+        return -EMSGSIZE;
+}
+
 int nfc_genl_device_added(struct nfc_dev *dev)
 {
         struct sk_buff *msg;
diff --git a/net/nfc/nfc.h b/net/nfc/nfc.h
index ec8794c1099c..2c868d2b3c57 100644
--- a/net/nfc/nfc.h
+++ b/net/nfc/nfc.h
@@ -119,6 +119,7 @@ void nfc_genl_data_init(struct nfc_genl_data *genl_data);
 void nfc_genl_data_exit(struct nfc_genl_data *genl_data);
 
 int nfc_genl_targets_found(struct nfc_dev *dev);
+int nfc_genl_target_lost(struct nfc_dev *dev, u32 target_idx);
 
 int nfc_genl_device_added(struct nfc_dev *dev);
 int nfc_genl_device_removed(struct nfc_dev *dev);